diff options
Diffstat (limited to 'arch/arc/net')
| -rw-r--r-- | arch/arc/net/Makefile | 6 | ||||
| -rw-r--r-- | arch/arc/net/bpf_jit.h | 164 | ||||
| -rw-r--r-- | arch/arc/net/bpf_jit_arcv2.c | 3007 | ||||
| -rw-r--r-- | arch/arc/net/bpf_jit_core.c | 1425 |
4 files changed, 4602 insertions, 0 deletions
diff --git a/arch/arc/net/Makefile b/arch/arc/net/Makefile new file mode 100644 index 0000000000..ea5790952e --- /dev/null +++ b/arch/arc/net/Makefile @@ -0,0 +1,6 @@ +# SPDX-License-Identifier: GPL-2.0-only + +ifeq ($(CONFIG_ISA_ARCV2),y) + obj-$(CONFIG_BPF_JIT) += bpf_jit_core.o + obj-$(CONFIG_BPF_JIT) += bpf_jit_arcv2.o +endif diff --git a/arch/arc/net/bpf_jit.h b/arch/arc/net/bpf_jit.h new file mode 100644 index 0000000000..495f3023e4 --- /dev/null +++ b/arch/arc/net/bpf_jit.h @@ -0,0 +1,164 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * The interface that a back-end should provide to bpf_jit_core.c. + * + * Copyright (c) 2024 Synopsys Inc. + * Author: Shahab Vahedi <shahab@synopsys.com> + */ + +#ifndef _ARC_BPF_JIT_H +#define _ARC_BPF_JIT_H + +#include <linux/bpf.h> +#include <linux/filter.h> + +/* Print debug info and assert. */ +//#define ARC_BPF_JIT_DEBUG + +/* Determine the address type of the target. */ +#ifdef CONFIG_ISA_ARCV2 +#define ARC_ADDR u32 +#endif + +/* + * For the translation of some BPF instructions, a temporary register + * might be needed for some interim data. + */ +#define JIT_REG_TMP MAX_BPF_JIT_REG + +/* + * Buffer access: If buffer "b" is not NULL, advance by "n" bytes. + * + * This macro must be used in any place that potentially requires a + * "buf + len". This way, we make sure that the "buf" argument for + * the underlying "arc_*(buf, ...)" ends up as NULL instead of something + * like "0+4" or "0+8", etc. Those "arc_*()" functions check their "buf" + * value to decide if instructions should be emitted or not. + */ +#define BUF(b, n) (((b) != NULL) ? ((b) + (n)) : (b)) + +/************** Functions that the back-end must provide **************/ +/* Extension for 32-bit operations. */ +u8 zext(u8 *buf, u8 rd); +/***** Moves *****/ +u8 mov_r32(u8 *buf, u8 rd, u8 rs, u8 sign_ext); +u8 mov_r32_i32(u8 *buf, u8 reg, s32 imm); +u8 mov_r64(u8 *buf, u8 rd, u8 rs, u8 sign_ext); +u8 mov_r64_i32(u8 *buf, u8 reg, s32 imm); +u8 mov_r64_i64(u8 *buf, u8 reg, u32 lo, u32 hi); +/***** Loads and stores *****/ +u8 load_r(u8 *buf, u8 rd, u8 rs, s16 off, u8 size, bool sign_ext); +u8 store_r(u8 *buf, u8 rd, u8 rs, s16 off, u8 size); +u8 store_i(u8 *buf, s32 imm, u8 rd, s16 off, u8 size); +/***** Addition *****/ +u8 add_r32(u8 *buf, u8 rd, u8 rs); +u8 add_r32_i32(u8 *buf, u8 rd, s32 imm); +u8 add_r64(u8 *buf, u8 rd, u8 rs); +u8 add_r64_i32(u8 *buf, u8 rd, s32 imm); +/***** Subtraction *****/ +u8 sub_r32(u8 *buf, u8 rd, u8 rs); +u8 sub_r32_i32(u8 *buf, u8 rd, s32 imm); +u8 sub_r64(u8 *buf, u8 rd, u8 rs); +u8 sub_r64_i32(u8 *buf, u8 rd, s32 imm); +/***** Multiplication *****/ +u8 mul_r32(u8 *buf, u8 rd, u8 rs); +u8 mul_r32_i32(u8 *buf, u8 rd, s32 imm); +u8 mul_r64(u8 *buf, u8 rd, u8 rs); +u8 mul_r64_i32(u8 *buf, u8 rd, s32 imm); +/***** Division *****/ +u8 div_r32(u8 *buf, u8 rd, u8 rs, bool sign_ext); +u8 div_r32_i32(u8 *buf, u8 rd, s32 imm, bool sign_ext); +/***** Remainder *****/ +u8 mod_r32(u8 *buf, u8 rd, u8 rs, bool sign_ext); +u8 mod_r32_i32(u8 *buf, u8 rd, s32 imm, bool sign_ext); +/***** Bitwise AND *****/ +u8 and_r32(u8 *buf, u8 rd, u8 rs); +u8 and_r32_i32(u8 *buf, u8 rd, s32 imm); +u8 and_r64(u8 *buf, u8 rd, u8 rs); +u8 and_r64_i32(u8 *buf, u8 rd, s32 imm); +/***** Bitwise OR *****/ +u8 or_r32(u8 *buf, u8 rd, u8 rs); +u8 or_r32_i32(u8 *buf, u8 rd, s32 imm); +u8 or_r64(u8 *buf, u8 rd, u8 rs); +u8 or_r64_i32(u8 *buf, u8 rd, s32 imm); +/***** Bitwise XOR *****/ +u8 xor_r32(u8 *buf, u8 rd, u8 rs); +u8 xor_r32_i32(u8 *buf, u8 rd, s32 imm); +u8 xor_r64(u8 *buf, u8 rd, u8 rs); +u8 xor_r64_i32(u8 *buf, u8 rd, s32 imm); +/***** Bitwise Negate *****/ +u8 neg_r32(u8 *buf, u8 r); +u8 neg_r64(u8 *buf, u8 r); +/***** Bitwise left shift *****/ +u8 lsh_r32(u8 *buf, u8 rd, u8 rs); +u8 lsh_r32_i32(u8 *buf, u8 rd, u8 imm); +u8 lsh_r64(u8 *buf, u8 rd, u8 rs); +u8 lsh_r64_i32(u8 *buf, u8 rd, s32 imm); +/***** Bitwise right shift (logical) *****/ +u8 rsh_r32(u8 *buf, u8 rd, u8 rs); +u8 rsh_r32_i32(u8 *buf, u8 rd, u8 imm); +u8 rsh_r64(u8 *buf, u8 rd, u8 rs); +u8 rsh_r64_i32(u8 *buf, u8 rd, s32 imm); +/***** Bitwise right shift (arithmetic) *****/ +u8 arsh_r32(u8 *buf, u8 rd, u8 rs); +u8 arsh_r32_i32(u8 *buf, u8 rd, u8 imm); +u8 arsh_r64(u8 *buf, u8 rd, u8 rs); +u8 arsh_r64_i32(u8 *buf, u8 rd, s32 imm); +/***** Frame related *****/ +u32 mask_for_used_regs(u8 bpf_reg, bool is_call); +u8 arc_prologue(u8 *buf, u32 usage, u16 frame_size); +u8 arc_epilogue(u8 *buf, u32 usage, u16 frame_size); +/***** Jumps *****/ +/* + * Different sorts of conditions (ARC enum as opposed to BPF_*). + * + * Do not change the order of enums here. ARC_CC_SLE+1 is used + * to determine the number of JCCs. + */ +enum ARC_CC { + ARC_CC_UGT = 0, /* unsigned > */ + ARC_CC_UGE, /* unsigned >= */ + ARC_CC_ULT, /* unsigned < */ + ARC_CC_ULE, /* unsigned <= */ + ARC_CC_SGT, /* signed > */ + ARC_CC_SGE, /* signed >= */ + ARC_CC_SLT, /* signed < */ + ARC_CC_SLE, /* signed <= */ + ARC_CC_AL, /* always */ + ARC_CC_EQ, /* == */ + ARC_CC_NE, /* != */ + ARC_CC_SET, /* test */ + ARC_CC_LAST +}; + +/* + * A few notes: + * + * - check_jmp_*() are prerequisites before calling the gen_jmp_*(). + * They return "true" if the jump is possible and "false" otherwise. + * + * - The notion of "*_off" is to emphasize that these parameters are + * merely offsets in the JIT stream and not absolute addresses. One + * can look at them as addresses if the JIT code would start from + * address 0x0000_0000. Nonetheless, since the buffer address for the + * JIT is on a word-aligned address, this works and actually makes + * things simpler (offsets are in the range of u32 which is more than + * enough). + */ +bool check_jmp_32(u32 curr_off, u32 targ_off, u8 cond); +bool check_jmp_64(u32 curr_off, u32 targ_off, u8 cond); +u8 gen_jmp_32(u8 *buf, u8 rd, u8 rs, u8 cond, u32 c_off, u32 t_off); +u8 gen_jmp_64(u8 *buf, u8 rd, u8 rs, u8 cond, u32 c_off, u32 t_off); +/***** Miscellaneous *****/ +u8 gen_func_call(u8 *buf, ARC_ADDR func_addr, bool external_func); +u8 arc_to_bpf_return(u8 *buf); +/* + * - Perform byte swaps on "rd" based on the "size". + * - If "force" is set, do it unconditionally. Otherwise, consider the + * desired "endian"ness and the host endianness. + * - For data "size"s up to 32 bits, perform a zero-extension if asked + * by the "do_zext" boolean. + */ +u8 gen_swap(u8 *buf, u8 rd, u8 size, u8 endian, bool force, bool do_zext); + +#endif /* _ARC_BPF_JIT_H */ diff --git a/arch/arc/net/bpf_jit_arcv2.c b/arch/arc/net/bpf_jit_arcv2.c new file mode 100644 index 0000000000..4458e409ca --- /dev/null +++ b/arch/arc/net/bpf_jit_arcv2.c @@ -0,0 +1,3007 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * The ARCv2 backend of Just-In-Time compiler for eBPF bytecode. + * + * Copyright (c) 2024 Synopsys Inc. + * Author: Shahab Vahedi <shahab@synopsys.com> + */ +#include <linux/bug.h> +#include "bpf_jit.h" + +/* ARC core registers. */ +enum { + ARC_R_0, ARC_R_1, ARC_R_2, ARC_R_3, ARC_R_4, ARC_R_5, + ARC_R_6, ARC_R_7, ARC_R_8, ARC_R_9, ARC_R_10, ARC_R_11, + ARC_R_12, ARC_R_13, ARC_R_14, ARC_R_15, ARC_R_16, ARC_R_17, + ARC_R_18, ARC_R_19, ARC_R_20, ARC_R_21, ARC_R_22, ARC_R_23, + ARC_R_24, ARC_R_25, ARC_R_26, ARC_R_FP, ARC_R_SP, ARC_R_ILINK, + ARC_R_30, ARC_R_BLINK, + /* + * Having ARC_R_IMM encoded as source register means there is an + * immediate that must be interpreted from the next 4 bytes. If + * encoded as the destination register though, it implies that the + * output of the operation is not assigned to any register. The + * latter is helpful if we only care about updating the CPU status + * flags. + */ + ARC_R_IMM = 62 +}; + +/* + * Remarks about the rationale behind the chosen mapping: + * + * - BPF_REG_{1,2,3,4} are the argument registers and must be mapped to + * argument registers in ARCv2 ABI: r0-r7. The r7 registers is the last + * argument register in the ABI. Therefore BPF_REG_5, as the fifth + * argument, must be pushed onto the stack. This is a must for calling + * in-kernel functions. + * + * - In ARCv2 ABI, the return value is in r0 for 32-bit results and (r1,r0) + * for 64-bit results. However, because they're already used for BPF_REG_1, + * the next available scratch registers, r8 and r9, are the best candidates + * for BPF_REG_0. After a "call" to a(n) (in-kernel) function, the result + * is "mov"ed to these registers. At a BPF_EXIT, their value is "mov"ed to + * (r1,r0). + * It is worth mentioning that scratch registers are the best choice for + * BPF_REG_0, because it is very popular in BPF instruction encoding. + * + * - JIT_REG_TMP is an artifact needed to translate some BPF instructions. + * Its life span is one single BPF instruction. Since during the + * analyze_reg_usage(), it is not known if temporary registers are used, + * it is mapped to ARC's scratch registers: r10 and r11. Therefore, they + * don't matter in analysing phase and don't need saving. This temporary + * register is added as yet another index in the bpf2arc array, so it will + * unfold like the rest of registers during the code generation process. + * + * - Mapping of callee-saved BPF registers, BPF_REG_{6,7,8,9}, starts from + * (r15,r14) register pair. The (r13,r12) is not a good choice, because + * in ARCv2 ABI, r12 is not a callee-saved register and this can cause + * problem when calling an in-kernel function. Theoretically, the mapping + * could start from (r14,r13), but it is not a conventional ARCv2 register + * pair. To have a future proof design, I opted for this arrangement. + * If/when we decide to add ARCv2 instructions that do use register pairs, + * the mapping, hopefully, doesn't need to be revisited. + */ +static const u8 bpf2arc[][2] = { + /* Return value from in-kernel function, and exit value from eBPF */ + [BPF_REG_0] = {ARC_R_8, ARC_R_9}, + /* Arguments from eBPF program to in-kernel function */ + [BPF_REG_1] = {ARC_R_0, ARC_R_1}, + [BPF_REG_2] = {ARC_R_2, ARC_R_3}, + [BPF_REG_3] = {ARC_R_4, ARC_R_5}, + [BPF_REG_4] = {ARC_R_6, ARC_R_7}, + /* Remaining arguments, to be passed on the stack per 32-bit ABI */ + [BPF_REG_5] = {ARC_R_22, ARC_R_23}, + /* Callee-saved registers that in-kernel function will preserve */ + [BPF_REG_6] = {ARC_R_14, ARC_R_15}, + [BPF_REG_7] = {ARC_R_16, ARC_R_17}, + [BPF_REG_8] = {ARC_R_18, ARC_R_19}, + [BPF_REG_9] = {ARC_R_20, ARC_R_21}, + /* Read-only frame pointer to access the eBPF stack. 32-bit only. */ + [BPF_REG_FP] = {ARC_R_FP, }, + /* Register for blinding constants */ + [BPF_REG_AX] = {ARC_R_24, ARC_R_25}, + /* Temporary registers for internal use */ + [JIT_REG_TMP] = {ARC_R_10, ARC_R_11} +}; + +#define ARC_CALLEE_SAVED_REG_FIRST ARC_R_13 +#define ARC_CALLEE_SAVED_REG_LAST ARC_R_25 + +#define REG_LO(r) (bpf2arc[(r)][0]) +#define REG_HI(r) (bpf2arc[(r)][1]) + +/* + * To comply with ARCv2 ABI, BPF's arg5 must be put on stack. After which, + * the stack needs to be restored by ARG5_SIZE. + */ +#define ARG5_SIZE 8 + +/* Instruction lengths in bytes. */ +enum { + INSN_len_normal = 4, /* Normal instructions length. */ + INSN_len_imm = 4 /* Length of an extra 32-bit immediate. */ +}; + +/* ZZ defines the size of operation in encodings that it is used. */ +enum { + ZZ_1_byte = 1, + ZZ_2_byte = 2, + ZZ_4_byte = 0, + ZZ_8_byte = 3 +}; + +/* + * AA is mostly about address write back mode. It determines if the + * address in question should be updated before usage or after: + * addr += offset; data = *addr; + * data = *addr; addr += offset; + * + * In "scaling" mode, the effective address will become the sum + * of "address" + "index"*"size". The "size" is specified by the + * "ZZ" field. There is no write back when AA is set for scaling: + * data = *(addr + offset<<zz) + */ +enum { + AA_none = 0, + AA_pre = 1, /* in assembly known as "a/aw". */ + AA_post = 2, /* in assembly known as "ab". */ + AA_scale = 3 /* in assembly known as "as". */ +}; + +/* X flag determines the mode of extension. */ +enum { + X_zero = 0, + X_sign = 1 +}; + +/* Condition codes. */ +enum { + CC_always = 0, /* condition is true all the time */ + CC_equal = 1, /* if status32.z flag is set */ + CC_unequal = 2, /* if status32.z flag is clear */ + CC_positive = 3, /* if status32.n flag is clear */ + CC_negative = 4, /* if status32.n flag is set */ + CC_less_u = 5, /* less than (unsigned) */ + CC_less_eq_u = 14, /* less than or equal (unsigned) */ + CC_great_eq_u = 6, /* greater than or equal (unsigned) */ + CC_great_u = 13, /* greater than (unsigned) */ + CC_less_s = 11, /* less than (signed) */ + CC_less_eq_s = 12, /* less than or equal (signed) */ + CC_great_eq_s = 10, /* greater than or equal (signed) */ + CC_great_s = 9 /* greater than (signed) */ +}; + +#define IN_U6_RANGE(x) ((x) <= (0x40 - 1) && (x) >= 0) +#define IN_S9_RANGE(x) ((x) <= (0x100 - 1) && (x) >= -0x100) +#define IN_S12_RANGE(x) ((x) <= (0x800 - 1) && (x) >= -0x800) +#define IN_S21_RANGE(x) ((x) <= (0x100000 - 1) && (x) >= -0x100000) +#define IN_S25_RANGE(x) ((x) <= (0x1000000 - 1) && (x) >= -0x1000000) + +/* Operands in most of the encodings. */ +#define OP_A(x) ((x) & 0x03f) +#define OP_B(x) ((((x) & 0x07) << 24) | (((x) & 0x38) << 9)) +#define OP_C(x) (((x) & 0x03f) << 6) +#define OP_IMM (OP_C(ARC_R_IMM)) +#define COND(x) (OP_A((x) & 31)) +#define FLAG(x) (((x) & 1) << 15) + +/* + * The 4-byte encoding of "mov b,c": + * + * 0010_0bbb 0000_1010 0BBB_cccc cc00_0000 + * + * b: BBBbbb destination register + * c: cccccc source register + */ +#define OPC_MOV 0x200a0000 + +/* + * The 4-byte encoding of "mov b,s12" (used for moving small immediates): + * + * 0010_0bbb 1000_1010 0BBB_ssss ssSS_SSSS + * + * b: BBBbbb destination register + * s: SSSSSSssssss source immediate (signed) + */ +#define OPC_MOVI 0x208a0000 +#define MOVI_S12(x) ((((x) & 0xfc0) >> 6) | (((x) & 0x3f) << 6)) + +/* + * The 4-byte encoding of "mov[.qq] b,u6", used for conditional + * moving of even smaller immediates: + * + * 0010_0bbb 1100_1010 0BBB_cccc cciq_qqqq + * + * qq: qqqqq condition code + * i: If set, c is considered a 6-bit immediate, else a reg. + * + * b: BBBbbb destination register + * c: cccccc source + */ +#define OPC_MOV_CC 0x20ca0000 +#define MOV_CC_I BIT(5) +#define OPC_MOVU_CC (OPC_MOV_CC | MOV_CC_I) + +/* + * The 4-byte encoding of "sexb b,c" (8-bit sign extension): + * + * 0010_0bbb 0010_1111 0BBB_cccc cc00_0101 + * + * b: BBBbbb destination register + * c: cccccc source register + */ +#define OPC_SEXB 0x202f0005 + +/* + * The 4-byte encoding of "sexh b,c" (16-bit sign extension): + * + * 0010_0bbb 0010_1111 0BBB_cccc cc00_0110 + * + * b: BBBbbb destination register + * c: cccccc source register + */ +#define OPC_SEXH 0x202f0006 + +/* + * The 4-byte encoding of "ld[zz][.x][.aa] c,[b,s9]": + * + * 0001_0bbb ssss_ssss SBBB_0aaz zxcc_cccc + * + * zz: size mode + * aa: address write back mode + * x: extension mode + * + * s9: S_ssss_ssss 9-bit signed number + * b: BBBbbb source reg for address + * c: cccccc destination register + */ +#define OPC_LOAD 0x10000000 +#define LOAD_X(x) ((x) << 6) +#define LOAD_ZZ(x) ((x) << 7) +#define LOAD_AA(x) ((x) << 9) +#define LOAD_S9(x) ((((x) & 0x0ff) << 16) | (((x) & 0x100) << 7)) +#define LOAD_C(x) ((x) & 0x03f) +/* Unsigned and signed loads. */ +#define OPC_LDU (OPC_LOAD | LOAD_X(X_zero)) +#define OPC_LDS (OPC_LOAD | LOAD_X(X_sign)) +/* 32-bit load. */ +#define OPC_LD32 (OPC_LDU | LOAD_ZZ(ZZ_4_byte)) +/* "pop reg" is merely a "ld.ab reg,[sp,4]". */ +#define OPC_POP \ + (OPC_LD32 | LOAD_AA(AA_post) | LOAD_S9(4) | OP_B(ARC_R_SP)) + +/* + * The 4-byte encoding of "st[zz][.aa] c,[b,s9]": + * + * 0001_1bbb ssss_ssss SBBB_cccc cc0a_azz0 + * + * zz: zz size mode + * aa: aa address write back mode + * + * s9: S_ssss_ssss 9-bit signed number + * b: BBBbbb source reg for address + * c: cccccc source reg to be stored + */ +#define OPC_STORE 0x18000000 +#define STORE_ZZ(x) ((x) << 1) +#define STORE_AA(x) ((x) << 3) +#define STORE_S9(x) ((((x) & 0x0ff) << 16) | (((x) & 0x100) << 7)) +/* 32-bit store. */ +#define OPC_ST32 (OPC_STORE | STORE_ZZ(ZZ_4_byte)) +/* "push reg" is merely a "st.aw reg,[sp,-4]". */ +#define OPC_PUSH \ + (OPC_ST32 | STORE_AA(AA_pre) | STORE_S9(-4) | OP_B(ARC_R_SP)) + +/* + * The 4-byte encoding of "add a,b,c": + * + * 0010_0bbb 0i00_0000 fBBB_cccc ccaa_aaaa + * + * f: indicates if flags (carry, etc.) should be updated + * i: If set, c is considered a 6-bit immediate, else a reg. + * + * a: aaaaaa result + * b: BBBbbb the 1st input operand + * c: cccccc the 2nd input operand + */ +#define OPC_ADD 0x20000000 +/* Addition with updating the pertinent flags in "status32" register. */ +#define OPC_ADDF (OPC_ADD | FLAG(1)) +#define ADDI BIT(22) +#define ADDI_U6(x) OP_C(x) +#define OPC_ADDI (OPC_ADD | ADDI) +#define OPC_ADDIF (OPC_ADDI | FLAG(1)) +#define OPC_ADD_I (OPC_ADD | OP_IMM) + +/* + * The 4-byte encoding of "adc a,b,c" (addition with carry): + * + * 0010_0bbb 0i00_0001 0BBB_cccc ccaa_aaaa + * + * i: if set, c is considered a 6-bit immediate, else a reg. + * + * a: aaaaaa result + * b: BBBbbb the 1st input operand + * c: cccccc the 2nd input operand + */ +#define OPC_ADC 0x20010000 +#define ADCI BIT(22) +#define ADCI_U6(x) OP_C(x) +#define OPC_ADCI (OPC_ADC | ADCI) + +/* + * The 4-byte encoding of "sub a,b,c": + * + * 0010_0bbb 0i00_0010 fBBB_cccc ccaa_aaaa + * + * f: indicates if flags (carry, etc.) should be updated + * i: if set, c is considered a 6-bit immediate, else a reg. + * + * a: aaaaaa result + * b: BBBbbb the 1st input operand + * c: cccccc the 2nd input operand + */ +#define OPC_SUB 0x20020000 +/* Subtraction with updating the pertinent flags in "status32" register. */ +#define OPC_SUBF (OPC_SUB | FLAG(1)) +#define SUBI BIT(22) +#define SUBI_U6(x) OP_C(x) +#define OPC_SUBI (OPC_SUB | SUBI) +#define OPC_SUB_I (OPC_SUB | OP_IMM) + +/* + * The 4-byte encoding of "sbc a,b,c" (subtraction with carry): + * + * 0010_0bbb 0000_0011 fBBB_cccc ccaa_aaaa + * + * f: indicates if flags (carry, etc.) should be updated + * + * a: aaaaaa result + * b: BBBbbb the 1st input operand + * c: cccccc the 2nd input operand + */ +#define OPC_SBC 0x20030000 + +/* + * The 4-byte encoding of "cmp[.qq] b,c": + * + * 0010_0bbb 1100_1100 1BBB_cccc cc0q_qqqq + * + * qq: qqqqq condition code + * + * b: BBBbbb the 1st operand + * c: cccccc the 2nd operand + */ +#define OPC_CMP 0x20cc8000 + +/* + * The 4-byte encoding of "neg a,b": + * + * 0010_0bbb 0100_1110 0BBB_0000 00aa_aaaa + * + * a: aaaaaa result + * b: BBBbbb input + */ +#define OPC_NEG 0x204e0000 + +/* + * The 4-byte encoding of "mpy a,b,c". + * mpy is the signed 32-bit multiplication with the lower 32-bit + * of the product as the result. + * + * 0010_0bbb 0001_1010 0BBB_cccc ccaa_aaaa + * + * a: aaaaaa result + * b: BBBbbb the 1st input operand + * c: cccccc the 2nd input operand + */ +#define OPC_MPY 0x201a0000 +#define OPC_MPYI (OPC_MPY | OP_IMM) + +/* + * The 4-byte encoding of "mpydu a,b,c". + * mpydu is the unsigned 32-bit multiplication with the lower 32-bit of + * the product in register "a" and the higher 32-bit in register "a+1". + * + * 0010_1bbb 0001_1001 0BBB_cccc ccaa_aaaa + * + * a: aaaaaa 64-bit result in registers (R_a+1,R_a) + * b: BBBbbb the 1st input operand + * c: cccccc the 2nd input operand + */ +#define OPC_MPYDU 0x28190000 +#define OPC_MPYDUI (OPC_MPYDU | OP_IMM) + +/* + * The 4-byte encoding of "divu a,b,c" (unsigned division): + * + * 0010_1bbb 0000_0101 0BBB_cccc ccaa_aaaa + * + * a: aaaaaa result (quotient) + * b: BBBbbb the 1st input operand + * c: cccccc the 2nd input operand (divisor) + */ +#define OPC_DIVU 0x28050000 +#define OPC_DIVUI (OPC_DIVU | OP_IMM) + +/* + * The 4-byte encoding of "div a,b,c" (signed division): + * + * 0010_1bbb 0000_0100 0BBB_cccc ccaa_aaaa + * + * a: aaaaaa result (quotient) + * b: BBBbbb the 1st input operand + * c: cccccc the 2nd input operand (divisor) + */ +#define OPC_DIVS 0x28040000 +#define OPC_DIVSI (OPC_DIVS | OP_IMM) + +/* + * The 4-byte encoding of "remu a,b,c" (unsigned remainder): + * + * 0010_1bbb 0000_1001 0BBB_cccc ccaa_aaaa + * + * a: aaaaaa result (remainder) + * b: BBBbbb the 1st input operand + * c: cccccc the 2nd input operand (divisor) + */ +#define OPC_REMU 0x28090000 +#define OPC_REMUI (OPC_REMU | OP_IMM) + +/* + * The 4-byte encoding of "rem a,b,c" (signed remainder): + * + * 0010_1bbb 0000_1000 0BBB_cccc ccaa_aaaa + * + * a: aaaaaa result (remainder) + * b: BBBbbb the 1st input operand + * c: cccccc the 2nd input operand (divisor) + */ +#define OPC_REMS 0x28080000 +#define OPC_REMSI (OPC_REMS | OP_IMM) + +/* + * The 4-byte encoding of "and a,b,c": + * + * 0010_0bbb 0000_0100 fBBB_cccc ccaa_aaaa + * + * f: indicates if zero and negative flags should be updated + * + * a: aaaaaa result + * b: BBBbbb the 1st input operand + * c: cccccc the 2nd input operand + */ +#define OPC_AND 0x20040000 +#define OPC_ANDI (OPC_AND | OP_IMM) + +/* + * The 4-byte encoding of "tst[.qq] b,c". + * Checks if the two input operands have any bit set at the same + * position. + * + * 0010_0bbb 1100_1011 1BBB_cccc cc0q_qqqq + * + * qq: qqqqq condition code + * + * b: BBBbbb the 1st input operand + * c: cccccc the 2nd input operand + */ +#define OPC_TST 0x20cb8000 + +/* + * The 4-byte encoding of "or a,b,c": + * + * 0010_0bbb 0000_0101 0BBB_cccc ccaa_aaaa + * + * a: aaaaaa result + * b: BBBbbb the 1st input operand + * c: cccccc the 2nd input operand + */ +#define OPC_OR 0x20050000 +#define OPC_ORI (OPC_OR | OP_IMM) + +/* + * The 4-byte encoding of "xor a,b,c": + * + * 0010_0bbb 0000_0111 0BBB_cccc ccaa_aaaa + * + * a: aaaaaa result + * b: BBBbbb the 1st input operand + * c: cccccc the 2nd input operand + */ +#define OPC_XOR 0x20070000 +#define OPC_XORI (OPC_XOR | OP_IMM) + +/* + * The 4-byte encoding of "not b,c": + * + * 0010_0bbb 0010_1111 0BBB_cccc cc00_1010 + * + * b: BBBbbb result + * c: cccccc input + */ +#define OPC_NOT 0x202f000a + +/* + * The 4-byte encoding of "btst b,u6": + * + * 0010_0bbb 0101_0001 1BBB_uuuu uu00_0000 + * + * b: BBBbbb input number to check + * u6: uuuuuu 6-bit unsigned number specifying bit position to check + */ +#define OPC_BTSTU6 0x20518000 +#define BTST_U6(x) (OP_C((x) & 63)) + +/* + * The 4-byte encoding of "asl[.qq] b,b,c" (arithmetic shift left): + * + * 0010_1bbb 0i00_0000 0BBB_cccc ccaa_aaaa + * + * i: if set, c is considered a 5-bit immediate, else a reg. + * + * b: BBBbbb result and the first operand (number to be shifted) + * c: cccccc amount to be shifted + */ +#define OPC_ASL 0x28000000 +#define ASL_I BIT(22) +#define ASLI_U6(x) OP_C((x) & 31) +#define OPC_ASLI (OPC_ASL | ASL_I) + +/* + * The 4-byte encoding of "asr a,b,c" (arithmetic shift right): + * + * 0010_1bbb 0i00_0010 0BBB_cccc ccaa_aaaa + * + * i: if set, c is considered a 6-bit immediate, else a reg. + * + * a: aaaaaa result + * b: BBBbbb first input: number to be shifted + * c: cccccc second input: amount to be shifted + */ +#define OPC_ASR 0x28020000 +#define ASR_I ASL_I +#define ASRI_U6(x) ASLI_U6(x) +#define OPC_ASRI (OPC_ASR | ASR_I) + +/* + * The 4-byte encoding of "lsr a,b,c" (logical shift right): + * + * 0010_1bbb 0i00_0001 0BBB_cccc ccaa_aaaa + * + * i: if set, c is considered a 6-bit immediate, else a reg. + * + * a: aaaaaa result + * b: BBBbbb first input: number to be shifted + * c: cccccc second input: amount to be shifted + */ +#define OPC_LSR 0x28010000 +#define LSR_I ASL_I +#define LSRI_U6(x) ASLI_U6(x) +#define OPC_LSRI (OPC_LSR | LSR_I) + +/* + * The 4-byte encoding of "swape b,c": + * + * 0010_1bbb 0010_1111 0bbb_cccc cc00_1001 + * + * b: BBBbbb destination register + * c: cccccc source register + */ +#define OPC_SWAPE 0x282f0009 + +/* + * Encoding for jump to an address in register: + * j reg_c + * + * 0010_0000 1110_0000 0000_cccc cc00_0000 + * + * c: cccccc register holding the destination address + */ +#define OPC_JMP 0x20e00000 +/* Jump to "branch-and-link" register, which effectively is a "return". */ +#define OPC_J_BLINK (OPC_JMP | OP_C(ARC_R_BLINK)) + +/* + * Encoding for jump-and-link to an address in register: + * jl reg_c + * + * 0010_0000 0010_0010 0000_cccc cc00_0000 + * + * c: cccccc register holding the destination address + */ +#define OPC_JL 0x20220000 + +/* + * Encoding for (conditional) branch to an offset from the current location + * that is word aligned: (PC & 0xffff_fffc) + s21 + * B[qq] s21 + * + * 0000_0sss ssss_sss0 SSSS_SSSS SS0q_qqqq + * + * qq: qqqqq condition code + * s21: SSSS SSSS_SSss ssss_ssss The displacement (21-bit signed) + * + * The displacement is supposed to be 16-bit (2-byte) aligned. Therefore, + * it should be a multiple of 2. Hence, there is an implied '0' bit at its + * LSB: S_SSSS SSSS_Ssss ssss_sss0 + */ +#define OPC_BCC 0x00000000 +#define BCC_S21(d) ((((d) & 0x7fe) << 16) | (((d) & 0x1ff800) >> 5)) + +/* + * Encoding for unconditional branch to an offset from the current location + * that is word aligned: (PC & 0xffff_fffc) + s25 + * B s25 + * + * 0000_0sss ssss_sss1 SSSS_SSSS SS00_TTTT + * + * s25: TTTT SSSS SSSS_SSss ssss_ssss The displacement (25-bit signed) + * + * The displacement is supposed to be 16-bit (2-byte) aligned. Therefore, + * it should be a multiple of 2. Hence, there is an implied '0' bit at its + * LSB: T TTTS_SSSS SSSS_Ssss ssss_sss0 + */ +#define OPC_B 0x00010000 +#define B_S25(d) ((((d) & 0x1e00000) >> 21) | BCC_S21(d)) + +static inline void emit_2_bytes(u8 *buf, u16 bytes) +{ + *((u16 *)buf) = bytes; +} + +static inline void emit_4_bytes(u8 *buf, u32 bytes) +{ + emit_2_bytes(buf, bytes >> 16); + emit_2_bytes(buf + 2, bytes & 0xffff); +} + +static inline u8 bpf_to_arc_size(u8 size) +{ + switch (size) { + case BPF_B: + return ZZ_1_byte; + case BPF_H: + return ZZ_2_byte; + case BPF_W: + return ZZ_4_byte; + case BPF_DW: + return ZZ_8_byte; + default: + return ZZ_4_byte; + } +} + +/************** Encoders (Deal with ARC regs) ************/ + +/* Move an immediate to register with a 4-byte instruction. */ +static u8 arc_movi_r(u8 *buf, u8 reg, s16 imm) +{ + const u32 insn = OPC_MOVI | OP_B(reg) | MOVI_S12(imm); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +/* rd <- rs */ +static u8 arc_mov_r(u8 *buf, u8 rd, u8 rs) +{ + const u32 insn = OPC_MOV | OP_B(rd) | OP_C(rs); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +/* The emitted code may have different sizes based on "imm". */ +static u8 arc_mov_i(u8 *buf, u8 rd, s32 imm) +{ + const u32 insn = OPC_MOV | OP_B(rd) | OP_IMM; + + if (IN_S12_RANGE(imm)) + return arc_movi_r(buf, rd, imm); + + if (buf) { + emit_4_bytes(buf, insn); + emit_4_bytes(buf + INSN_len_normal, imm); + } + return INSN_len_normal + INSN_len_imm; +} + +/* The emitted code will always have the same size (8). */ +static u8 arc_mov_i_fixed(u8 *buf, u8 rd, s32 imm) +{ + const u32 insn = OPC_MOV | OP_B(rd) | OP_IMM; + + if (buf) { + emit_4_bytes(buf, insn); + emit_4_bytes(buf + INSN_len_normal, imm); + } + return INSN_len_normal + INSN_len_imm; +} + +/* Conditional move. */ +static u8 arc_mov_cc_r(u8 *buf, u8 cc, u8 rd, u8 rs) +{ + const u32 insn = OPC_MOV_CC | OP_B(rd) | OP_C(rs) | COND(cc); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +/* Conditional move of a small immediate to rd. */ +static u8 arc_movu_cc_r(u8 *buf, u8 cc, u8 rd, u8 imm) +{ + const u32 insn = OPC_MOVU_CC | OP_B(rd) | OP_C(imm) | COND(cc); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +/* Sign extension from a byte. */ +static u8 arc_sexb_r(u8 *buf, u8 rd, u8 rs) +{ + const u32 insn = OPC_SEXB | OP_B(rd) | OP_C(rs); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +/* Sign extension from two bytes. */ +static u8 arc_sexh_r(u8 *buf, u8 rd, u8 rs) +{ + const u32 insn = OPC_SEXH | OP_B(rd) | OP_C(rs); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +/* st reg, [reg_mem, off] */ +static u8 arc_st_r(u8 *buf, u8 reg, u8 reg_mem, s16 off, u8 zz) +{ + const u32 insn = OPC_STORE | STORE_ZZ(zz) | OP_C(reg) | + OP_B(reg_mem) | STORE_S9(off); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +/* st.aw reg, [sp, -4] */ +static u8 arc_push_r(u8 *buf, u8 reg) +{ + const u32 insn = OPC_PUSH | OP_C(reg); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +/* ld reg, [reg_mem, off] (unsigned) */ +static u8 arc_ld_r(u8 *buf, u8 reg, u8 reg_mem, s16 off, u8 zz) +{ + const u32 insn = OPC_LDU | LOAD_ZZ(zz) | LOAD_C(reg) | + OP_B(reg_mem) | LOAD_S9(off); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +/* ld.x reg, [reg_mem, off] (sign extend) */ +static u8 arc_ldx_r(u8 *buf, u8 reg, u8 reg_mem, s16 off, u8 zz) +{ + const u32 insn = OPC_LDS | LOAD_ZZ(zz) | LOAD_C(reg) | + OP_B(reg_mem) | LOAD_S9(off); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +/* ld.ab reg,[sp,4] */ +static u8 arc_pop_r(u8 *buf, u8 reg) +{ + const u32 insn = OPC_POP | LOAD_C(reg); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +/* add Ra,Ra,Rc */ +static u8 arc_add_r(u8 *buf, u8 ra, u8 rc) +{ + const u32 insn = OPC_ADD | OP_A(ra) | OP_B(ra) | OP_C(rc); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +/* add.f Ra,Ra,Rc */ +static u8 arc_addf_r(u8 *buf, u8 ra, u8 rc) +{ + const u32 insn = OPC_ADDF | OP_A(ra) | OP_B(ra) | OP_C(rc); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +/* add.f Ra,Ra,u6 */ +static u8 arc_addif_r(u8 *buf, u8 ra, u8 u6) +{ + const u32 insn = OPC_ADDIF | OP_A(ra) | OP_B(ra) | ADDI_U6(u6); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +/* add Ra,Ra,u6 */ +static u8 arc_addi_r(u8 *buf, u8 ra, u8 u6) +{ + const u32 insn = OPC_ADDI | OP_A(ra) | OP_B(ra) | ADDI_U6(u6); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +/* add Ra,Rb,imm */ +static u8 arc_add_i(u8 *buf, u8 ra, u8 rb, s32 imm) +{ + const u32 insn = OPC_ADD_I | OP_A(ra) | OP_B(rb); + + if (buf) { + emit_4_bytes(buf, insn); + emit_4_bytes(buf + INSN_len_normal, imm); + } + return INSN_len_normal + INSN_len_imm; +} + +/* adc Ra,Ra,Rc */ +static u8 arc_adc_r(u8 *buf, u8 ra, u8 rc) +{ + const u32 insn = OPC_ADC | OP_A(ra) | OP_B(ra) | OP_C(rc); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +/* adc Ra,Ra,u6 */ +static u8 arc_adci_r(u8 *buf, u8 ra, u8 u6) +{ + const u32 insn = OPC_ADCI | OP_A(ra) | OP_B(ra) | ADCI_U6(u6); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +/* sub Ra,Ra,Rc */ +static u8 arc_sub_r(u8 *buf, u8 ra, u8 rc) +{ + const u32 insn = OPC_SUB | OP_A(ra) | OP_B(ra) | OP_C(rc); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +/* sub.f Ra,Ra,Rc */ +static u8 arc_subf_r(u8 *buf, u8 ra, u8 rc) +{ + const u32 insn = OPC_SUBF | OP_A(ra) | OP_B(ra) | OP_C(rc); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +/* sub Ra,Ra,u6 */ +static u8 arc_subi_r(u8 *buf, u8 ra, u8 u6) +{ + const u32 insn = OPC_SUBI | OP_A(ra) | OP_B(ra) | SUBI_U6(u6); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +/* sub Ra,Ra,imm */ +static u8 arc_sub_i(u8 *buf, u8 ra, s32 imm) +{ + const u32 insn = OPC_SUB_I | OP_A(ra) | OP_B(ra); + + if (buf) { + emit_4_bytes(buf, insn); + emit_4_bytes(buf + INSN_len_normal, imm); + } + return INSN_len_normal + INSN_len_imm; +} + +/* sbc Ra,Ra,Rc */ +static u8 arc_sbc_r(u8 *buf, u8 ra, u8 rc) +{ + const u32 insn = OPC_SBC | OP_A(ra) | OP_B(ra) | OP_C(rc); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +/* cmp Rb,Rc */ +static u8 arc_cmp_r(u8 *buf, u8 rb, u8 rc) +{ + const u32 insn = OPC_CMP | OP_B(rb) | OP_C(rc); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +/* + * cmp.z Rb,Rc + * + * This "cmp.z" variant of compare instruction is used on lower + * 32-bits of register pairs after "cmp"ing their upper parts. If the + * upper parts are equal (z), then this one will proceed to check the + * rest. + */ +static u8 arc_cmpz_r(u8 *buf, u8 rb, u8 rc) +{ + const u32 insn = OPC_CMP | OP_B(rb) | OP_C(rc) | CC_equal; + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +/* neg Ra,Rb */ +static u8 arc_neg_r(u8 *buf, u8 ra, u8 rb) +{ + const u32 insn = OPC_NEG | OP_A(ra) | OP_B(rb); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +/* mpy Ra,Rb,Rc */ +static u8 arc_mpy_r(u8 *buf, u8 ra, u8 rb, u8 rc) +{ + const u32 insn = OPC_MPY | OP_A(ra) | OP_B(rb) | OP_C(rc); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +/* mpy Ra,Rb,imm */ +static u8 arc_mpy_i(u8 *buf, u8 ra, u8 rb, s32 imm) +{ + const u32 insn = OPC_MPYI | OP_A(ra) | OP_B(rb); + + if (buf) { + emit_4_bytes(buf, insn); + emit_4_bytes(buf + INSN_len_normal, imm); + } + return INSN_len_normal + INSN_len_imm; +} + +/* mpydu Ra,Ra,Rc */ +static u8 arc_mpydu_r(u8 *buf, u8 ra, u8 rc) +{ + const u32 insn = OPC_MPYDU | OP_A(ra) | OP_B(ra) | OP_C(rc); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +/* mpydu Ra,Ra,imm */ +static u8 arc_mpydu_i(u8 *buf, u8 ra, s32 imm) +{ + const u32 insn = OPC_MPYDUI | OP_A(ra) | OP_B(ra); + + if (buf) { + emit_4_bytes(buf, insn); + emit_4_bytes(buf + INSN_len_normal, imm); + } + return INSN_len_normal + INSN_len_imm; +} + +/* divu Rd,Rd,Rs */ +static u8 arc_divu_r(u8 *buf, u8 rd, u8 rs) +{ + const u32 insn = OPC_DIVU | OP_A(rd) | OP_B(rd) | OP_C(rs); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +/* divu Rd,Rd,imm */ +static u8 arc_divu_i(u8 *buf, u8 rd, s32 imm) +{ + const u32 insn = OPC_DIVUI | OP_A(rd) | OP_B(rd); + + if (buf) { + emit_4_bytes(buf, insn); + emit_4_bytes(buf + INSN_len_normal, imm); + } + return INSN_len_normal + INSN_len_imm; +} + +/* div Rd,Rd,Rs */ +static u8 arc_divs_r(u8 *buf, u8 rd, u8 rs) +{ + const u32 insn = OPC_DIVS | OP_A(rd) | OP_B(rd) | OP_C(rs); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +/* div Rd,Rd,imm */ +static u8 arc_divs_i(u8 *buf, u8 rd, s32 imm) +{ + const u32 insn = OPC_DIVSI | OP_A(rd) | OP_B(rd); + + if (buf) { + emit_4_bytes(buf, insn); + emit_4_bytes(buf + INSN_len_normal, imm); + } + return INSN_len_normal + INSN_len_imm; +} + +/* remu Rd,Rd,Rs */ +static u8 arc_remu_r(u8 *buf, u8 rd, u8 rs) +{ + const u32 insn = OPC_REMU | OP_A(rd) | OP_B(rd) | OP_C(rs); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +/* remu Rd,Rd,imm */ +static u8 arc_remu_i(u8 *buf, u8 rd, s32 imm) +{ + const u32 insn = OPC_REMUI | OP_A(rd) | OP_B(rd); + + if (buf) { + emit_4_bytes(buf, insn); + emit_4_bytes(buf + INSN_len_normal, imm); + } + return INSN_len_normal + INSN_len_imm; +} + +/* rem Rd,Rd,Rs */ +static u8 arc_rems_r(u8 *buf, u8 rd, u8 rs) +{ + const u32 insn = OPC_REMS | OP_A(rd) | OP_B(rd) | OP_C(rs); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +/* rem Rd,Rd,imm */ +static u8 arc_rems_i(u8 *buf, u8 rd, s32 imm) +{ + const u32 insn = OPC_REMSI | OP_A(rd) | OP_B(rd); + + if (buf) { + emit_4_bytes(buf, insn); + emit_4_bytes(buf + INSN_len_normal, imm); + } + return INSN_len_normal + INSN_len_imm; +} + +/* and Rd,Rd,Rs */ +static u8 arc_and_r(u8 *buf, u8 rd, u8 rs) +{ + const u32 insn = OPC_AND | OP_A(rd) | OP_B(rd) | OP_C(rs); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +/* and Rd,Rd,limm */ +static u8 arc_and_i(u8 *buf, u8 rd, s32 imm) +{ + const u32 insn = OPC_ANDI | OP_A(rd) | OP_B(rd); + + if (buf) { + emit_4_bytes(buf, insn); + emit_4_bytes(buf + INSN_len_normal, imm); + } + return INSN_len_normal + INSN_len_imm; +} + +/* tst Rd,Rs */ +static u8 arc_tst_r(u8 *buf, u8 rd, u8 rs) +{ + const u32 insn = OPC_TST | OP_B(rd) | OP_C(rs); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +/* + * This particular version, "tst.z ...", is meant to be used after a + * "tst" on the low 32-bit of register pairs. If that "tst" is not + * zero, then we don't need to test the upper 32-bits lest it sets + * the zero flag. + */ +static u8 arc_tstz_r(u8 *buf, u8 rd, u8 rs) +{ + const u32 insn = OPC_TST | OP_B(rd) | OP_C(rs) | CC_equal; + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +static u8 arc_or_r(u8 *buf, u8 rd, u8 rs1, u8 rs2) +{ + const u32 insn = OPC_OR | OP_A(rd) | OP_B(rs1) | OP_C(rs2); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +static u8 arc_or_i(u8 *buf, u8 rd, s32 imm) +{ + const u32 insn = OPC_ORI | OP_A(rd) | OP_B(rd); + + if (buf) { + emit_4_bytes(buf, insn); + emit_4_bytes(buf + INSN_len_normal, imm); + } + return INSN_len_normal + INSN_len_imm; +} + +static u8 arc_xor_r(u8 *buf, u8 rd, u8 rs) +{ + const u32 insn = OPC_XOR | OP_A(rd) | OP_B(rd) | OP_C(rs); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +static u8 arc_xor_i(u8 *buf, u8 rd, s32 imm) +{ + const u32 insn = OPC_XORI | OP_A(rd) | OP_B(rd); + + if (buf) { + emit_4_bytes(buf, insn); + emit_4_bytes(buf + INSN_len_normal, imm); + } + return INSN_len_normal + INSN_len_imm; +} + +static u8 arc_not_r(u8 *buf, u8 rd, u8 rs) +{ + const u32 insn = OPC_NOT | OP_B(rd) | OP_C(rs); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +static u8 arc_btst_i(u8 *buf, u8 rs, u8 imm) +{ + const u32 insn = OPC_BTSTU6 | OP_B(rs) | BTST_U6(imm); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +static u8 arc_asl_r(u8 *buf, u8 rd, u8 rs1, u8 rs2) +{ + const u32 insn = OPC_ASL | OP_A(rd) | OP_B(rs1) | OP_C(rs2); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +static u8 arc_asli_r(u8 *buf, u8 rd, u8 rs, u8 imm) +{ + const u32 insn = OPC_ASLI | OP_A(rd) | OP_B(rs) | ASLI_U6(imm); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +static u8 arc_asr_r(u8 *buf, u8 rd, u8 rs1, u8 rs2) +{ + const u32 insn = OPC_ASR | OP_A(rd) | OP_B(rs1) | OP_C(rs2); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +static u8 arc_asri_r(u8 *buf, u8 rd, u8 rs, u8 imm) +{ + const u32 insn = OPC_ASRI | OP_A(rd) | OP_B(rs) | ASRI_U6(imm); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +static u8 arc_lsr_r(u8 *buf, u8 rd, u8 rs1, u8 rs2) +{ + const u32 insn = OPC_LSR | OP_A(rd) | OP_B(rs1) | OP_C(rs2); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +static u8 arc_lsri_r(u8 *buf, u8 rd, u8 rs, u8 imm) +{ + const u32 insn = OPC_LSRI | OP_A(rd) | OP_B(rs) | LSRI_U6(imm); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +static u8 arc_swape_r(u8 *buf, u8 r) +{ + const u32 insn = OPC_SWAPE | OP_B(r) | OP_C(r); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +static u8 arc_jmp_return(u8 *buf) +{ + if (buf) + emit_4_bytes(buf, OPC_J_BLINK); + return INSN_len_normal; +} + +static u8 arc_jl(u8 *buf, u8 reg) +{ + const u32 insn = OPC_JL | OP_C(reg); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +/* + * Conditional jump to an address that is max 21 bits away (signed). + * + * b<cc> s21 + */ +static u8 arc_bcc(u8 *buf, u8 cc, int offset) +{ + const u32 insn = OPC_BCC | BCC_S21(offset) | COND(cc); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +/* + * Unconditional jump to an address that is max 25 bits away (signed). + * + * b s25 + */ +static u8 arc_b(u8 *buf, s32 offset) +{ + const u32 insn = OPC_B | B_S25(offset); + + if (buf) + emit_4_bytes(buf, insn); + return INSN_len_normal; +} + +/************* Packers (Deal with BPF_REGs) **************/ + +u8 zext(u8 *buf, u8 rd) +{ + if (rd != BPF_REG_FP) + return arc_movi_r(buf, REG_HI(rd), 0); + else + return 0; +} + +u8 mov_r32(u8 *buf, u8 rd, u8 rs, u8 sign_ext) +{ + u8 len = 0; + + if (sign_ext) { + if (sign_ext == 8) + len = arc_sexb_r(buf, REG_LO(rd), REG_LO(rs)); + else if (sign_ext == 16) + len = arc_sexh_r(buf, REG_LO(rd), REG_LO(rs)); + else if (sign_ext == 32 && rd != rs) + len = arc_mov_r(buf, REG_LO(rd), REG_LO(rs)); + + return len; + } + + /* Unsigned move. */ + + if (rd != rs) + len = arc_mov_r(buf, REG_LO(rd), REG_LO(rs)); + + return len; +} + +u8 mov_r32_i32(u8 *buf, u8 reg, s32 imm) +{ + return arc_mov_i(buf, REG_LO(reg), imm); +} + +u8 mov_r64(u8 *buf, u8 rd, u8 rs, u8 sign_ext) +{ + u8 len = 0; + + if (sign_ext) { + /* First handle the low 32-bit part. */ + len = mov_r32(buf, rd, rs, sign_ext); + + /* Now propagate the sign bit of LO to HI. */ + if (sign_ext == 8 || sign_ext == 16 || sign_ext == 32) { + len += arc_asri_r(BUF(buf, len), + REG_HI(rd), REG_LO(rd), 31); + } + + return len; + } + + /* Unsigned move. */ + + if (rd == rs) + return 0; + + len = arc_mov_r(buf, REG_LO(rd), REG_LO(rs)); + + if (rs != BPF_REG_FP) + len += arc_mov_r(BUF(buf, len), REG_HI(rd), REG_HI(rs)); + /* BPF_REG_FP is mapped to 32-bit "fp" register. */ + else + len += arc_movi_r(BUF(buf, len), REG_HI(rd), 0); + + return len; +} + +/* Sign extend the 32-bit immediate into 64-bit register pair. */ +u8 mov_r64_i32(u8 *buf, u8 reg, s32 imm) +{ + u8 len = 0; + + len = arc_mov_i(buf, REG_LO(reg), imm); + + /* BPF_REG_FP is mapped to 32-bit "fp" register. */ + if (reg != BPF_REG_FP) { + if (imm >= 0) + len += arc_movi_r(BUF(buf, len), REG_HI(reg), 0); + else + len += arc_movi_r(BUF(buf, len), REG_HI(reg), -1); + } + + return len; +} + +/* + * This is merely used for translation of "LD R, IMM64" instructions + * of the BPF. These sort of instructions are sometimes used for + * relocations. If during the normal pass, the relocation value is + * not known, the BPF instruction may look something like: + * + * LD R <- 0x0000_0001_0000_0001 + * + * Which will nicely translate to two 4-byte ARC instructions: + * + * mov R_lo, 1 # imm is small enough to be s12 + * mov R_hi, 1 # same + * + * However, during the extra pass, the IMM64 will have changed + * to the resolved address and looks something like: + * + * LD R <- 0x0000_0000_1234_5678 + * + * Now, the translated code will require 12 bytes: + * + * mov R_lo, 0x12345678 # this is an 8-byte instruction + * mov R_hi, 0 # still 4 bytes + * + * Which in practice will result in overwriting the following + * instruction. To avoid such cases, we will always emit codes + * with fixed sizes. + */ +u8 mov_r64_i64(u8 *buf, u8 reg, u32 lo, u32 hi) +{ + u8 len; + + len = arc_mov_i_fixed(buf, REG_LO(reg), lo); + len += arc_mov_i_fixed(BUF(buf, len), REG_HI(reg), hi); + + return len; +} + +/* + * If the "off"set is too big (doesn't encode as S9) for: + * + * {ld,st} r, [rm, off] + * + * Then emit: + * + * add r10, REG_LO(rm), off + * + * and make sure that r10 becomes the effective address: + * + * {ld,st} r, [r10, 0] + */ +static u8 adjust_mem_access(u8 *buf, s16 *off, u8 size, + u8 rm, u8 *arc_reg_mem) +{ + u8 len = 0; + *arc_reg_mem = REG_LO(rm); + + if (!IN_S9_RANGE(*off) || + (size == BPF_DW && !IN_S9_RANGE(*off + 4))) { + len += arc_add_i(BUF(buf, len), + REG_LO(JIT_REG_TMP), REG_LO(rm), (u32)(*off)); + *arc_reg_mem = REG_LO(JIT_REG_TMP); + *off = 0; + } + + return len; +} + +/* store rs, [rd, off] */ +u8 store_r(u8 *buf, u8 rs, u8 rd, s16 off, u8 size) +{ + u8 len, arc_reg_mem; + + len = adjust_mem_access(buf, &off, size, rd, &arc_reg_mem); + + if (size == BPF_DW) { + len += arc_st_r(BUF(buf, len), REG_LO(rs), arc_reg_mem, + off, ZZ_4_byte); + len += arc_st_r(BUF(buf, len), REG_HI(rs), arc_reg_mem, + off + 4, ZZ_4_byte); + } else { + u8 zz = bpf_to_arc_size(size); + + len += arc_st_r(BUF(buf, len), REG_LO(rs), arc_reg_mem, + off, zz); + } + + return len; +} + +/* + * For {8,16,32}-bit stores: + * mov r21, imm + * st r21, [...] + * For 64-bit stores: + * mov r21, imm + * st r21, [...] + * mov r21, {0,-1} + * st r21, [...+4] + */ +u8 store_i(u8 *buf, s32 imm, u8 rd, s16 off, u8 size) +{ + u8 len, arc_reg_mem; + /* REG_LO(JIT_REG_TMP) might be used by "adjust_mem_access()". */ + const u8 arc_rs = REG_HI(JIT_REG_TMP); + + len = adjust_mem_access(buf, &off, size, rd, &arc_reg_mem); + + if (size == BPF_DW) { + len += arc_mov_i(BUF(buf, len), arc_rs, imm); + len += arc_st_r(BUF(buf, len), arc_rs, arc_reg_mem, + off, ZZ_4_byte); + imm = (imm >= 0 ? 0 : -1); + len += arc_mov_i(BUF(buf, len), arc_rs, imm); + len += arc_st_r(BUF(buf, len), arc_rs, arc_reg_mem, + off + 4, ZZ_4_byte); + } else { + u8 zz = bpf_to_arc_size(size); + + len += arc_mov_i(BUF(buf, len), arc_rs, imm); + len += arc_st_r(BUF(buf, len), arc_rs, arc_reg_mem, off, zz); + } + + return len; +} + +/* + * For the calling convention of a little endian machine, the LO part + * must be on top of the stack. + */ +static u8 push_r64(u8 *buf, u8 reg) +{ + u8 len = 0; + +#ifdef __LITTLE_ENDIAN + /* BPF_REG_FP is mapped to 32-bit "fp" register. */ + if (reg != BPF_REG_FP) + len += arc_push_r(BUF(buf, len), REG_HI(reg)); + len += arc_push_r(BUF(buf, len), REG_LO(reg)); +#else + len += arc_push_r(BUF(buf, len), REG_LO(reg)); + if (reg != BPF_REG_FP) + len += arc_push_r(BUF(buf, len), REG_HI(reg)); +#endif + + return len; +} + +/* load rd, [rs, off] */ +u8 load_r(u8 *buf, u8 rd, u8 rs, s16 off, u8 size, bool sign_ext) +{ + u8 len, arc_reg_mem; + + len = adjust_mem_access(buf, &off, size, rs, &arc_reg_mem); + + if (size == BPF_B || size == BPF_H || size == BPF_W) { + const u8 zz = bpf_to_arc_size(size); + + /* Use LD.X only if the data size is less than 32-bit. */ + if (sign_ext && (zz == ZZ_1_byte || zz == ZZ_2_byte)) { + len += arc_ldx_r(BUF(buf, len), REG_LO(rd), + arc_reg_mem, off, zz); + } else { + len += arc_ld_r(BUF(buf, len), REG_LO(rd), + arc_reg_mem, off, zz); + } + + if (sign_ext) { + /* Propagate the sign bit to the higher reg. */ + len += arc_asri_r(BUF(buf, len), + REG_HI(rd), REG_LO(rd), 31); + } else { + len += arc_movi_r(BUF(buf, len), REG_HI(rd), 0); + } + } else if (size == BPF_DW) { + /* + * We are about to issue 2 consecutive loads: + * + * ld rx, [rb, off+0] + * ld ry, [rb, off+4] + * + * If "rx" and "rb" are the same registers, then the order + * should change to guarantee that "rb" remains intact + * during these 2 operations: + * + * ld ry, [rb, off+4] + * ld rx, [rb, off+0] + */ + if (REG_LO(rd) != arc_reg_mem) { + len += arc_ld_r(BUF(buf, len), REG_LO(rd), arc_reg_mem, + off, ZZ_4_byte); + len += arc_ld_r(BUF(buf, len), REG_HI(rd), arc_reg_mem, + off + 4, ZZ_4_byte); + } else { + len += arc_ld_r(BUF(buf, len), REG_HI(rd), arc_reg_mem, + off + 4, ZZ_4_byte); + len += arc_ld_r(BUF(buf, len), REG_LO(rd), arc_reg_mem, + off, ZZ_4_byte); + } + } + + return len; +} + +u8 add_r32(u8 *buf, u8 rd, u8 rs) +{ + return arc_add_r(buf, REG_LO(rd), REG_LO(rs)); +} + +u8 add_r32_i32(u8 *buf, u8 rd, s32 imm) +{ + if (IN_U6_RANGE(imm)) + return arc_addi_r(buf, REG_LO(rd), imm); + else + return arc_add_i(buf, REG_LO(rd), REG_LO(rd), imm); +} + +u8 add_r64(u8 *buf, u8 rd, u8 rs) +{ + u8 len; + + len = arc_addf_r(buf, REG_LO(rd), REG_LO(rs)); + len += arc_adc_r(BUF(buf, len), REG_HI(rd), REG_HI(rs)); + return len; +} + +u8 add_r64_i32(u8 *buf, u8 rd, s32 imm) +{ + u8 len; + + if (IN_U6_RANGE(imm)) { + len = arc_addif_r(buf, REG_LO(rd), imm); + len += arc_adci_r(BUF(buf, len), REG_HI(rd), 0); + } else { + len = mov_r64_i32(buf, JIT_REG_TMP, imm); + len += add_r64(BUF(buf, len), rd, JIT_REG_TMP); + } + return len; +} + +u8 sub_r32(u8 *buf, u8 rd, u8 rs) +{ + return arc_sub_r(buf, REG_LO(rd), REG_LO(rs)); +} + +u8 sub_r32_i32(u8 *buf, u8 rd, s32 imm) +{ + if (IN_U6_RANGE(imm)) + return arc_subi_r(buf, REG_LO(rd), imm); + else + return arc_sub_i(buf, REG_LO(rd), imm); +} + +u8 sub_r64(u8 *buf, u8 rd, u8 rs) +{ + u8 len; + + len = arc_subf_r(buf, REG_LO(rd), REG_LO(rs)); + len += arc_sbc_r(BUF(buf, len), REG_HI(rd), REG_HI(rs)); + return len; +} + +u8 sub_r64_i32(u8 *buf, u8 rd, s32 imm) +{ + u8 len; + + len = mov_r64_i32(buf, JIT_REG_TMP, imm); + len += sub_r64(BUF(buf, len), rd, JIT_REG_TMP); + return len; +} + +static u8 cmp_r32(u8 *buf, u8 rd, u8 rs) +{ + return arc_cmp_r(buf, REG_LO(rd), REG_LO(rs)); +} + +u8 neg_r32(u8 *buf, u8 r) +{ + return arc_neg_r(buf, REG_LO(r), REG_LO(r)); +} + +/* In a two's complement system, -r is (~r + 1). */ +u8 neg_r64(u8 *buf, u8 r) +{ + u8 len; + + len = arc_not_r(buf, REG_LO(r), REG_LO(r)); + len += arc_not_r(BUF(buf, len), REG_HI(r), REG_HI(r)); + len += add_r64_i32(BUF(buf, len), r, 1); + return len; +} + +u8 mul_r32(u8 *buf, u8 rd, u8 rs) +{ + return arc_mpy_r(buf, REG_LO(rd), REG_LO(rd), REG_LO(rs)); +} + +u8 mul_r32_i32(u8 *buf, u8 rd, s32 imm) +{ + return arc_mpy_i(buf, REG_LO(rd), REG_LO(rd), imm); +} + +/* + * MUL B, C + * -------- + * mpy t0, B_hi, C_lo + * mpy t1, B_lo, C_hi + * mpydu B_lo, B_lo, C_lo + * add B_hi, B_hi, t0 + * add B_hi, B_hi, t1 + */ +u8 mul_r64(u8 *buf, u8 rd, u8 rs) +{ + const u8 t0 = REG_LO(JIT_REG_TMP); + const u8 t1 = REG_HI(JIT_REG_TMP); + const u8 C_lo = REG_LO(rs); + const u8 C_hi = REG_HI(rs); + const u8 B_lo = REG_LO(rd); + const u8 B_hi = REG_HI(rd); + u8 len; + + len = arc_mpy_r(buf, t0, B_hi, C_lo); + len += arc_mpy_r(BUF(buf, len), t1, B_lo, C_hi); + len += arc_mpydu_r(BUF(buf, len), B_lo, C_lo); + len += arc_add_r(BUF(buf, len), B_hi, t0); + len += arc_add_r(BUF(buf, len), B_hi, t1); + + return len; +} + +/* + * MUL B, imm + * ---------- + * + * To get a 64-bit result from a signed 64x32 multiplication: + * + * B_hi B_lo * + * sign imm + * ----------------------------- + * HI(B_lo*imm) LO(B_lo*imm) + + * B_hi*imm + + * B_lo*sign + * ----------------------------- + * res_hi res_lo + * + * mpy t1, B_lo, sign(imm) + * mpy t0, B_hi, imm + * mpydu B_lo, B_lo, imm + * add B_hi, B_hi, t0 + * add B_hi, B_hi, t1 + * + * Note: We can't use signed double multiplication, "mpyd", instead of an + * unsigned version, "mpydu", and then get rid of the sign adjustments + * calculated in "t1". The signed multiplication, "mpyd", will consider + * both operands, "B_lo" and "imm", as signed inputs. However, for this + * 64x32 multiplication, "B_lo" must be treated as an unsigned number. + */ +u8 mul_r64_i32(u8 *buf, u8 rd, s32 imm) +{ + const u8 t0 = REG_LO(JIT_REG_TMP); + const u8 t1 = REG_HI(JIT_REG_TMP); + const u8 B_lo = REG_LO(rd); + const u8 B_hi = REG_HI(rd); + u8 len = 0; + + if (imm == 1) + return 0; + + /* Is the sign-extension of the immediate "-1"? */ + if (imm < 0) + len += arc_neg_r(BUF(buf, len), t1, B_lo); + + len += arc_mpy_i(BUF(buf, len), t0, B_hi, imm); + len += arc_mpydu_i(BUF(buf, len), B_lo, imm); + len += arc_add_r(BUF(buf, len), B_hi, t0); + + /* Add the "sign*B_lo" part, if necessary. */ + if (imm < 0) + len += arc_add_r(BUF(buf, len), B_hi, t1); + + return len; +} + +u8 div_r32(u8 *buf, u8 rd, u8 rs, bool sign_ext) +{ + if (sign_ext) + return arc_divs_r(buf, REG_LO(rd), REG_LO(rs)); + else + return arc_divu_r(buf, REG_LO(rd), REG_LO(rs)); +} + +u8 div_r32_i32(u8 *buf, u8 rd, s32 imm, bool sign_ext) +{ + if (imm == 0) + return 0; + + if (sign_ext) + return arc_divs_i(buf, REG_LO(rd), imm); + else + return arc_divu_i(buf, REG_LO(rd), imm); +} + +u8 mod_r32(u8 *buf, u8 rd, u8 rs, bool sign_ext) +{ + if (sign_ext) + return arc_rems_r(buf, REG_LO(rd), REG_LO(rs)); + else + return arc_remu_r(buf, REG_LO(rd), REG_LO(rs)); +} + +u8 mod_r32_i32(u8 *buf, u8 rd, s32 imm, bool sign_ext) +{ + if (imm == 0) + return 0; + + if (sign_ext) + return arc_rems_i(buf, REG_LO(rd), imm); + else + return arc_remu_i(buf, REG_LO(rd), imm); +} + +u8 and_r32(u8 *buf, u8 rd, u8 rs) +{ + return arc_and_r(buf, REG_LO(rd), REG_LO(rs)); +} + +u8 and_r32_i32(u8 *buf, u8 rd, s32 imm) +{ + return arc_and_i(buf, REG_LO(rd), imm); +} + +u8 and_r64(u8 *buf, u8 rd, u8 rs) +{ + u8 len; + + len = arc_and_r(buf, REG_LO(rd), REG_LO(rs)); + len += arc_and_r(BUF(buf, len), REG_HI(rd), REG_HI(rs)); + return len; +} + +u8 and_r64_i32(u8 *buf, u8 rd, s32 imm) +{ + u8 len; + + len = mov_r64_i32(buf, JIT_REG_TMP, imm); + len += and_r64(BUF(buf, len), rd, JIT_REG_TMP); + return len; +} + +static u8 tst_r32(u8 *buf, u8 rd, u8 rs) +{ + return arc_tst_r(buf, REG_LO(rd), REG_LO(rs)); +} + +u8 or_r32(u8 *buf, u8 rd, u8 rs) +{ + return arc_or_r(buf, REG_LO(rd), REG_LO(rd), REG_LO(rs)); +} + +u8 or_r32_i32(u8 *buf, u8 rd, s32 imm) +{ + return arc_or_i(buf, REG_LO(rd), imm); +} + +u8 or_r64(u8 *buf, u8 rd, u8 rs) +{ + u8 len; + + len = arc_or_r(buf, REG_LO(rd), REG_LO(rd), REG_LO(rs)); + len += arc_or_r(BUF(buf, len), REG_HI(rd), REG_HI(rd), REG_HI(rs)); + return len; +} + +u8 or_r64_i32(u8 *buf, u8 rd, s32 imm) +{ + u8 len; + + len = mov_r64_i32(buf, JIT_REG_TMP, imm); + len += or_r64(BUF(buf, len), rd, JIT_REG_TMP); + return len; +} + +u8 xor_r32(u8 *buf, u8 rd, u8 rs) +{ + return arc_xor_r(buf, REG_LO(rd), REG_LO(rs)); +} + +u8 xor_r32_i32(u8 *buf, u8 rd, s32 imm) +{ + return arc_xor_i(buf, REG_LO(rd), imm); +} + +u8 xor_r64(u8 *buf, u8 rd, u8 rs) +{ + u8 len; + + len = arc_xor_r(buf, REG_LO(rd), REG_LO(rs)); + len += arc_xor_r(BUF(buf, len), REG_HI(rd), REG_HI(rs)); + return len; +} + +u8 xor_r64_i32(u8 *buf, u8 rd, s32 imm) +{ + u8 len; + + len = mov_r64_i32(buf, JIT_REG_TMP, imm); + len += xor_r64(BUF(buf, len), rd, JIT_REG_TMP); + return len; +} + +/* "asl a,b,c" --> "a = (b << (c & 31))". */ +u8 lsh_r32(u8 *buf, u8 rd, u8 rs) +{ + return arc_asl_r(buf, REG_LO(rd), REG_LO(rd), REG_LO(rs)); +} + +u8 lsh_r32_i32(u8 *buf, u8 rd, u8 imm) +{ + return arc_asli_r(buf, REG_LO(rd), REG_LO(rd), imm); +} + +/* + * algorithm + * --------- + * if (n <= 32) + * to_hi = lo >> (32-n) # (32-n) is the negate of "n" in a 5-bit width. + * lo <<= n + * hi <<= n + * hi |= to_hi + * else + * hi = lo << (n-32) + * lo = 0 + * + * assembly translation for "LSH B, C" + * (heavily influenced by ARC gcc) + * ----------------------------------- + * not t0, C_lo # The first 3 lines are almost the same as: + * lsr t1, B_lo, 1 # neg t0, C_lo + * lsr t1, t1, t0 # lsr t1, B_lo, t0 --> t1 is "to_hi" + * mov t0, C_lo* # with one important difference. In "neg" + * asl B_lo, B_lo, t0 # version, when C_lo=0, t1 becomes B_lo while + * asl B_hi, B_hi, t0 # it should be 0. The "not" approach instead, + * or B_hi, B_hi, t1 # "shift"s t1 once and 31 times, practically + * btst t0, 5 # setting it to 0 when C_lo=0. + * mov.ne B_hi, B_lo** + * mov.ne B_lo, 0 + * + * *The "mov t0, C_lo" is necessary to cover the cases that C is the same + * register as B. + * + * **ARC performs a shift in this manner: B <<= (C & 31) + * For 32<=n<64, "n-32" and "n&31" are the same. Therefore, "B << n" and + * "B << (n-32)" yield the same results. e.g. the results of "B << 35" and + * "B << 3" are the same. + * + * The behaviour is undefined for n >= 64. + */ +u8 lsh_r64(u8 *buf, u8 rd, u8 rs) +{ + const u8 t0 = REG_LO(JIT_REG_TMP); + const u8 t1 = REG_HI(JIT_REG_TMP); + const u8 C_lo = REG_LO(rs); + const u8 B_lo = REG_LO(rd); + const u8 B_hi = REG_HI(rd); + u8 len; + + len = arc_not_r(buf, t0, C_lo); + len += arc_lsri_r(BUF(buf, len), t1, B_lo, 1); + len += arc_lsr_r(BUF(buf, len), t1, t1, t0); + len += arc_mov_r(BUF(buf, len), t0, C_lo); + len += arc_asl_r(BUF(buf, len), B_lo, B_lo, t0); + len += arc_asl_r(BUF(buf, len), B_hi, B_hi, t0); + len += arc_or_r(BUF(buf, len), B_hi, B_hi, t1); + len += arc_btst_i(BUF(buf, len), t0, 5); + len += arc_mov_cc_r(BUF(buf, len), CC_unequal, B_hi, B_lo); + len += arc_movu_cc_r(BUF(buf, len), CC_unequal, B_lo, 0); + + return len; +} + +/* + * if (n < 32) + * to_hi = B_lo >> 32-n # extract upper n bits + * lo <<= n + * hi <<=n + * hi |= to_hi + * else if (n < 64) + * hi = lo << n-32 + * lo = 0 + */ +u8 lsh_r64_i32(u8 *buf, u8 rd, s32 imm) +{ + const u8 t0 = REG_LO(JIT_REG_TMP); + const u8 B_lo = REG_LO(rd); + const u8 B_hi = REG_HI(rd); + const u8 n = (u8)imm; + u8 len = 0; + + if (n == 0) { + return 0; + } else if (n <= 31) { + len = arc_lsri_r(buf, t0, B_lo, 32 - n); + len += arc_asli_r(BUF(buf, len), B_lo, B_lo, n); + len += arc_asli_r(BUF(buf, len), B_hi, B_hi, n); + len += arc_or_r(BUF(buf, len), B_hi, B_hi, t0); + } else if (n <= 63) { + len = arc_asli_r(buf, B_hi, B_lo, n - 32); + len += arc_movi_r(BUF(buf, len), B_lo, 0); + } + /* n >= 64 is undefined behaviour. */ + + return len; +} + +/* "lsr a,b,c" --> "a = (b >> (c & 31))". */ +u8 rsh_r32(u8 *buf, u8 rd, u8 rs) +{ + return arc_lsr_r(buf, REG_LO(rd), REG_LO(rd), REG_LO(rs)); +} + +u8 rsh_r32_i32(u8 *buf, u8 rd, u8 imm) +{ + return arc_lsri_r(buf, REG_LO(rd), REG_LO(rd), imm); +} + +/* + * For better commentary, see lsh_r64(). + * + * algorithm + * --------- + * if (n <= 32) + * to_lo = hi << (32-n) + * hi >>= n + * lo >>= n + * lo |= to_lo + * else + * lo = hi >> (n-32) + * hi = 0 + * + * RSH B,C + * ---------- + * not t0, C_lo + * asl t1, B_hi, 1 + * asl t1, t1, t0 + * mov t0, C_lo + * lsr B_hi, B_hi, t0 + * lsr B_lo, B_lo, t0 + * or B_lo, B_lo, t1 + * btst t0, 5 + * mov.ne B_lo, B_hi + * mov.ne B_hi, 0 + */ +u8 rsh_r64(u8 *buf, u8 rd, u8 rs) +{ + const u8 t0 = REG_LO(JIT_REG_TMP); + const u8 t1 = REG_HI(JIT_REG_TMP); + const u8 C_lo = REG_LO(rs); + const u8 B_lo = REG_LO(rd); + const u8 B_hi = REG_HI(rd); + u8 len; + + len = arc_not_r(buf, t0, C_lo); + len += arc_asli_r(BUF(buf, len), t1, B_hi, 1); + len += arc_asl_r(BUF(buf, len), t1, t1, t0); + len += arc_mov_r(BUF(buf, len), t0, C_lo); + len += arc_lsr_r(BUF(buf, len), B_hi, B_hi, t0); + len += arc_lsr_r(BUF(buf, len), B_lo, B_lo, t0); + len += arc_or_r(BUF(buf, len), B_lo, B_lo, t1); + len += arc_btst_i(BUF(buf, len), t0, 5); + len += arc_mov_cc_r(BUF(buf, len), CC_unequal, B_lo, B_hi); + len += arc_movu_cc_r(BUF(buf, len), CC_unequal, B_hi, 0); + + return len; +} + +/* + * if (n < 32) + * to_lo = B_lo << 32-n # extract lower n bits, right-padded with 32-n 0s + * lo >>=n + * hi >>=n + * hi |= to_lo + * else if (n < 64) + * lo = hi >> n-32 + * hi = 0 + */ +u8 rsh_r64_i32(u8 *buf, u8 rd, s32 imm) +{ + const u8 t0 = REG_LO(JIT_REG_TMP); + const u8 B_lo = REG_LO(rd); + const u8 B_hi = REG_HI(rd); + const u8 n = (u8)imm; + u8 len = 0; + + if (n == 0) { + return 0; + } else if (n <= 31) { + len = arc_asli_r(buf, t0, B_hi, 32 - n); + len += arc_lsri_r(BUF(buf, len), B_lo, B_lo, n); + len += arc_lsri_r(BUF(buf, len), B_hi, B_hi, n); + len += arc_or_r(BUF(buf, len), B_lo, B_lo, t0); + } else if (n <= 63) { + len = arc_lsri_r(buf, B_lo, B_hi, n - 32); + len += arc_movi_r(BUF(buf, len), B_hi, 0); + } + /* n >= 64 is undefined behaviour. */ + + return len; +} + +/* "asr a,b,c" --> "a = (b s>> (c & 31))". */ +u8 arsh_r32(u8 *buf, u8 rd, u8 rs) +{ + return arc_asr_r(buf, REG_LO(rd), REG_LO(rd), REG_LO(rs)); +} + +u8 arsh_r32_i32(u8 *buf, u8 rd, u8 imm) +{ + return arc_asri_r(buf, REG_LO(rd), REG_LO(rd), imm); +} + +/* + * For comparison, see rsh_r64(). + * + * algorithm + * --------- + * if (n <= 32) + * to_lo = hi << (32-n) + * hi s>>= n + * lo >>= n + * lo |= to_lo + * else + * hi_sign = hi s>>31 + * lo = hi s>> (n-32) + * hi = hi_sign + * + * ARSH B,C + * ---------- + * not t0, C_lo + * asl t1, B_hi, 1 + * asl t1, t1, t0 + * mov t0, C_lo + * asr B_hi, B_hi, t0 + * lsr B_lo, B_lo, t0 + * or B_lo, B_lo, t1 + * btst t0, 5 + * asr t0, B_hi, 31 # now, t0 = 0 or -1 based on B_hi's sign + * mov.ne B_lo, B_hi + * mov.ne B_hi, t0 + */ +u8 arsh_r64(u8 *buf, u8 rd, u8 rs) +{ + const u8 t0 = REG_LO(JIT_REG_TMP); + const u8 t1 = REG_HI(JIT_REG_TMP); + const u8 C_lo = REG_LO(rs); + const u8 B_lo = REG_LO(rd); + const u8 B_hi = REG_HI(rd); + u8 len; + + len = arc_not_r(buf, t0, C_lo); + len += arc_asli_r(BUF(buf, len), t1, B_hi, 1); + len += arc_asl_r(BUF(buf, len), t1, t1, t0); + len += arc_mov_r(BUF(buf, len), t0, C_lo); + len += arc_asr_r(BUF(buf, len), B_hi, B_hi, t0); + len += arc_lsr_r(BUF(buf, len), B_lo, B_lo, t0); + len += arc_or_r(BUF(buf, len), B_lo, B_lo, t1); + len += arc_btst_i(BUF(buf, len), t0, 5); + len += arc_asri_r(BUF(buf, len), t0, B_hi, 31); + len += arc_mov_cc_r(BUF(buf, len), CC_unequal, B_lo, B_hi); + len += arc_mov_cc_r(BUF(buf, len), CC_unequal, B_hi, t0); + + return len; +} + +/* + * if (n < 32) + * to_lo = lo << 32-n # extract lower n bits, right-padded with 32-n 0s + * lo >>=n + * hi s>>=n + * hi |= to_lo + * else if (n < 64) + * lo = hi s>> n-32 + * hi = (lo[msb] ? -1 : 0) + */ +u8 arsh_r64_i32(u8 *buf, u8 rd, s32 imm) +{ + const u8 t0 = REG_LO(JIT_REG_TMP); + const u8 B_lo = REG_LO(rd); + const u8 B_hi = REG_HI(rd); + const u8 n = (u8)imm; + u8 len = 0; + + if (n == 0) { + return 0; + } else if (n <= 31) { + len = arc_asli_r(buf, t0, B_hi, 32 - n); + len += arc_lsri_r(BUF(buf, len), B_lo, B_lo, n); + len += arc_asri_r(BUF(buf, len), B_hi, B_hi, n); + len += arc_or_r(BUF(buf, len), B_lo, B_lo, t0); + } else if (n <= 63) { + len = arc_asri_r(buf, B_lo, B_hi, n - 32); + len += arc_movi_r(BUF(buf, len), B_hi, -1); + len += arc_btst_i(BUF(buf, len), B_lo, 31); + len += arc_movu_cc_r(BUF(buf, len), CC_equal, B_hi, 0); + } + /* n >= 64 is undefined behaviour. */ + + return len; +} + +u8 gen_swap(u8 *buf, u8 rd, u8 size, u8 endian, bool force, bool do_zext) +{ + u8 len = 0; +#ifdef __BIG_ENDIAN + const u8 host_endian = BPF_FROM_BE; +#else + const u8 host_endian = BPF_FROM_LE; +#endif + if (host_endian != endian || force) { + switch (size) { + case 16: + /* + * r = B4B3_B2B1 << 16 --> r = B2B1_0000 + * then, swape(r) would become the desired 0000_B1B2 + */ + len = arc_asli_r(buf, REG_LO(rd), REG_LO(rd), 16); + fallthrough; + case 32: + len += arc_swape_r(BUF(buf, len), REG_LO(rd)); + if (do_zext) + len += zext(BUF(buf, len), rd); + break; + case 64: + /* + * swap "hi" and "lo": + * hi ^= lo; + * lo ^= hi; + * hi ^= lo; + * and then swap the bytes in "hi" and "lo". + */ + len = arc_xor_r(buf, REG_HI(rd), REG_LO(rd)); + len += arc_xor_r(BUF(buf, len), REG_LO(rd), REG_HI(rd)); + len += arc_xor_r(BUF(buf, len), REG_HI(rd), REG_LO(rd)); + len += arc_swape_r(BUF(buf, len), REG_LO(rd)); + len += arc_swape_r(BUF(buf, len), REG_HI(rd)); + break; + default: + /* The caller must have handled this. */ + break; + } + } else { + /* + * If the same endianness, there's not much to do other + * than zeroing out the upper bytes based on the "size". + */ + switch (size) { + case 16: + len = arc_and_i(buf, REG_LO(rd), 0xffff); + fallthrough; + case 32: + if (do_zext) + len += zext(BUF(buf, len), rd); + break; + case 64: + break; + default: + /* The caller must have handled this. */ + break; + } + } + + return len; +} + +/* + * To create a frame, all that is needed is: + * + * push fp + * mov fp, sp + * sub sp, <frame_size> + * + * "push fp" is taken care of separately while saving the clobbered registers. + * All that remains is copying SP value to FP and shrinking SP's address space + * for any possible function call to come. + */ +static inline u8 frame_create(u8 *buf, u16 size) +{ + u8 len; + + len = arc_mov_r(buf, ARC_R_FP, ARC_R_SP); + if (IN_U6_RANGE(size)) + len += arc_subi_r(BUF(buf, len), ARC_R_SP, size); + else + len += arc_sub_i(BUF(buf, len), ARC_R_SP, size); + return len; +} + +/* + * mov sp, fp + * + * The value of SP upon entering was copied to FP. + */ +static inline u8 frame_restore(u8 *buf) +{ + return arc_mov_r(buf, ARC_R_SP, ARC_R_FP); +} + +/* + * Going from a JITed code to the native caller: + * + * mov ARC_ABI_RET_lo, BPF_REG_0_lo # r0 <- r8 + * mov ARC_ABI_RET_hi, BPF_REG_0_hi # r1 <- r9 + */ +static u8 bpf_to_arc_return(u8 *buf) +{ + u8 len; + + len = arc_mov_r(buf, ARC_R_0, REG_LO(BPF_REG_0)); + len += arc_mov_r(BUF(buf, len), ARC_R_1, REG_HI(BPF_REG_0)); + return len; +} + +/* + * Coming back from an external (in-kernel) function to the JITed code: + * + * mov ARC_ABI_RET_lo, BPF_REG_0_lo # r8 <- r0 + * mov ARC_ABI_RET_hi, BPF_REG_0_hi # r9 <- r1 + */ +u8 arc_to_bpf_return(u8 *buf) +{ + u8 len; + + len = arc_mov_r(buf, REG_LO(BPF_REG_0), ARC_R_0); + len += arc_mov_r(BUF(buf, len), REG_HI(BPF_REG_0), ARC_R_1); + return len; +} + +/* + * This translation leads to: + * + * mov r10, addr # always an 8-byte instruction + * jl [r10] + * + * The length of the "mov" must be fixed (8), otherwise it may diverge + * during the normal and extra passes: + * + * normal pass extra pass + * + * 180: mov r10,0 | 180: mov r10,0x700578d8 + * 184: jl [r10] | 188: jl [r10] + * 188: add.f r16,r16,0x1 | 18c: adc r17,r17,0 + * 18c: adc r17,r17,0 | + * + * In the above example, the change from "r10 <- 0" to "r10 <- 0x700578d8" + * has led to an increase in the length of the "mov" instruction. + * Inadvertently, that caused the loss of the "add.f" instruction. + */ +static u8 jump_and_link(u8 *buf, u32 addr) +{ + u8 len; + + len = arc_mov_i_fixed(buf, REG_LO(JIT_REG_TMP), addr); + len += arc_jl(BUF(buf, len), REG_LO(JIT_REG_TMP)); + return len; +} + +/* + * This function determines which ARC registers must be saved and restored. + * It does so by looking into: + * + * "bpf_reg": The clobbered (destination) BPF register + * "is_call": Indicator if the current instruction is a call + * + * When a register of interest is clobbered, its corresponding bit position + * in return value, "usage", is set to true. + */ +u32 mask_for_used_regs(u8 bpf_reg, bool is_call) +{ + u32 usage = 0; + + /* BPF registers that must be saved. */ + if (bpf_reg >= BPF_REG_6 && bpf_reg <= BPF_REG_9) { + usage |= BIT(REG_LO(bpf_reg)); + usage |= BIT(REG_HI(bpf_reg)); + /* + * Using the frame pointer register implies that it should + * be saved and reinitialised with the current frame data. + */ + } else if (bpf_reg == BPF_REG_FP) { + usage |= BIT(REG_LO(BPF_REG_FP)); + /* Could there be some ARC registers that must to be saved? */ + } else { + if (REG_LO(bpf_reg) >= ARC_CALLEE_SAVED_REG_FIRST && + REG_LO(bpf_reg) <= ARC_CALLEE_SAVED_REG_LAST) + usage |= BIT(REG_LO(bpf_reg)); + + if (REG_HI(bpf_reg) >= ARC_CALLEE_SAVED_REG_FIRST && + REG_HI(bpf_reg) <= ARC_CALLEE_SAVED_REG_LAST) + usage |= BIT(REG_HI(bpf_reg)); + } + + /* A "call" indicates that ARC's "blink" reg must be saved. */ + usage |= is_call ? BIT(ARC_R_BLINK) : 0; + + return usage; +} + +/* + * push blink # if blink is marked as clobbered + * push r[0-n] # if r[i] is marked as clobbered + * push fp # if fp is marked as clobbered + * mov fp, sp # if frame_size > 0 (clobbers fp) + * sub sp, <frame_size> # same as above + */ +u8 arc_prologue(u8 *buf, u32 usage, u16 frame_size) +{ + u8 len = 0; + u32 gp_regs = 0; + + /* Deal with blink first. */ + if (usage & BIT(ARC_R_BLINK)) + len += arc_push_r(BUF(buf, len), ARC_R_BLINK); + + gp_regs = usage & ~(BIT(ARC_R_BLINK) | BIT(ARC_R_FP)); + while (gp_regs) { + u8 reg = __builtin_ffs(gp_regs) - 1; + + len += arc_push_r(BUF(buf, len), reg); + gp_regs &= ~BIT(reg); + } + + /* Deal with fp last. */ + if ((usage & BIT(ARC_R_FP)) || frame_size > 0) + len += arc_push_r(BUF(buf, len), ARC_R_FP); + + if (frame_size > 0) + len += frame_create(BUF(buf, len), frame_size); + +#ifdef ARC_BPF_JIT_DEBUG + if ((usage & BIT(ARC_R_FP)) && frame_size == 0) { + pr_err("FP is being saved while there is no frame."); + BUG(); + } +#endif + + return len; +} + +/* + * mov sp, fp # if frame_size > 0 + * pop fp # if fp is marked as clobbered + * pop r[n-0] # if r[i] is marked as clobbered + * pop blink # if blink is marked as clobbered + * mov r0, r8 # always: ABI_return <- BPF_return + * mov r1, r9 # continuation of above + * j [blink] # always + * + * "fp being marked as clobbered" and "frame_size > 0" are the two sides of + * the same coin. + */ +u8 arc_epilogue(u8 *buf, u32 usage, u16 frame_size) +{ + u32 len = 0; + u32 gp_regs = 0; + +#ifdef ARC_BPF_JIT_DEBUG + if ((usage & BIT(ARC_R_FP)) && frame_size == 0) { + pr_err("FP is being saved while there is no frame."); + BUG(); + } +#endif + + if (frame_size > 0) + len += frame_restore(BUF(buf, len)); + + /* Deal with fp first. */ + if ((usage & BIT(ARC_R_FP)) || frame_size > 0) + len += arc_pop_r(BUF(buf, len), ARC_R_FP); + + gp_regs = usage & ~(BIT(ARC_R_BLINK) | BIT(ARC_R_FP)); + while (gp_regs) { + /* "usage" is 32-bit, each bit indicating an ARC register. */ + u8 reg = 31 - __builtin_clz(gp_regs); + + len += arc_pop_r(BUF(buf, len), reg); + gp_regs &= ~BIT(reg); + } + + /* Deal with blink last. */ + if (usage & BIT(ARC_R_BLINK)) + len += arc_pop_r(BUF(buf, len), ARC_R_BLINK); + + /* Wrap up the return value and jump back to the caller. */ + len += bpf_to_arc_return(BUF(buf, len)); + len += arc_jmp_return(BUF(buf, len)); + + return len; +} + +/* + * For details on the algorithm, see the comments of "gen_jcc_64()". + * + * This data structure is holding information for jump translations. + * + * jit_off: How many bytes into the current JIT address, "b"ranch insn. occurs + * cond: The condition that the ARC branch instruction must use + * + * e.g.: + * + * BPF_JGE R1, R0, @target + * ------------------------ + * | + * v + * 0x1000: cmp r3, r1 # 0x1000 is the JIT address for "BPF_JGE ..." insn + * 0x1004: bhi @target # first jump (branch higher) + * 0x1008: blo @end # second jump acting as a skip (end is 0x1014) + * 0x100C: cmp r2, r0 # the lower 32 bits are evaluated + * 0x1010: bhs @target # third jump (branch higher or same) + * 0x1014: ... + * + * The jit_off(set) of the "bhi" is 4 bytes. + * The cond(ition) for the "bhi" is "CC_great_u". + * + * The jit_off(set) is necessary for calculating the exact displacement + * to the "target" address: + * + * jit_address + jit_off(set) - @target + * 0x1000 + 4 - @target + */ +#define JCC64_NR_OF_JMPS 3 /* Number of jumps in jcc64 template. */ +#define JCC64_INSNS_TO_END 3 /* Number of insn. inclusive the 2nd jmp to end. */ +#define JCC64_SKIP_JMP 1 /* Index of the "skip" jump to "end". */ +static const struct { + /* + * "jit_off" is common between all "jmp[]" and is coupled with + * "cond" of each "jmp[]" instance. e.g.: + * + * arcv2_64_jccs.jit_off[1] + * arcv2_64_jccs.jmp[ARC_CC_UGT].cond[1] + * + * Are indicating that the second jump in JITed code of "UGT" + * is at offset "jit_off[1]" while its condition is "cond[1]". + */ + u8 jit_off[JCC64_NR_OF_JMPS]; + + struct { + u8 cond[JCC64_NR_OF_JMPS]; + } jmp[ARC_CC_SLE + 1]; +} arcv2_64_jccs = { + .jit_off = { + INSN_len_normal * 1, + INSN_len_normal * 2, + INSN_len_normal * 4 + }, + /* + * cmp rd_hi, rs_hi + * bhi @target # 1: u> + * blo @end # 2: u< + * cmp rd_lo, rs_lo + * bhi @target # 3: u> + * end: + */ + .jmp[ARC_CC_UGT] = { + .cond = {CC_great_u, CC_less_u, CC_great_u} + }, + /* + * cmp rd_hi, rs_hi + * bhi @target # 1: u> + * blo @end # 2: u< + * cmp rd_lo, rs_lo + * bhs @target # 3: u>= + * end: + */ + .jmp[ARC_CC_UGE] = { + .cond = {CC_great_u, CC_less_u, CC_great_eq_u} + }, + /* + * cmp rd_hi, rs_hi + * blo @target # 1: u< + * bhi @end # 2: u> + * cmp rd_lo, rs_lo + * blo @target # 3: u< + * end: + */ + .jmp[ARC_CC_ULT] = { + .cond = {CC_less_u, CC_great_u, CC_less_u} + }, + /* + * cmp rd_hi, rs_hi + * blo @target # 1: u< + * bhi @end # 2: u> + * cmp rd_lo, rs_lo + * bls @target # 3: u<= + * end: + */ + .jmp[ARC_CC_ULE] = { + .cond = {CC_less_u, CC_great_u, CC_less_eq_u} + }, + /* + * cmp rd_hi, rs_hi + * bgt @target # 1: s> + * blt @end # 2: s< + * cmp rd_lo, rs_lo + * bhi @target # 3: u> + * end: + */ + .jmp[ARC_CC_SGT] = { + .cond = {CC_great_s, CC_less_s, CC_great_u} + }, + /* + * cmp rd_hi, rs_hi + * bgt @target # 1: s> + * blt @end # 2: s< + * cmp rd_lo, rs_lo + * bhs @target # 3: u>= + * end: + */ + .jmp[ARC_CC_SGE] = { + .cond = {CC_great_s, CC_less_s, CC_great_eq_u} + }, + /* + * cmp rd_hi, rs_hi + * blt @target # 1: s< + * bgt @end # 2: s> + * cmp rd_lo, rs_lo + * blo @target # 3: u< + * end: + */ + .jmp[ARC_CC_SLT] = { + .cond = {CC_less_s, CC_great_s, CC_less_u} + }, + /* + * cmp rd_hi, rs_hi + * blt @target # 1: s< + * bgt @end # 2: s> + * cmp rd_lo, rs_lo + * bls @target # 3: u<= + * end: + */ + .jmp[ARC_CC_SLE] = { + .cond = {CC_less_s, CC_great_s, CC_less_eq_u} + } +}; + +/* + * The displacement (offset) for ARC's "b"ranch instruction is the distance + * from the aligned version of _current_ instruction (PCL) to the target + * instruction: + * + * DISP = TARGET - PCL # PCL is the word aligned PC + */ +static inline s32 get_displacement(u32 curr_off, u32 targ_off) +{ + return (s32)(targ_off - (curr_off & ~3L)); +} + +/* + * "disp"lacement should be: + * + * 1. 16-bit aligned. + * 2. fit in S25, because no "condition code" is supposed to be encoded. + */ +static inline bool is_valid_far_disp(s32 disp) +{ + return (!(disp & 1) && IN_S25_RANGE(disp)); +} + +/* + * "disp"lacement should be: + * + * 1. 16-bit aligned. + * 2. fit in S21, because "condition code" is supposed to be encoded too. + */ +static inline bool is_valid_near_disp(s32 disp) +{ + return (!(disp & 1) && IN_S21_RANGE(disp)); +} + +/* + * cmp rd_hi, rs_hi + * cmp.z rd_lo, rs_lo + * b{eq,ne} @target + * | | + * | `--> "eq" param is false (JNE) + * `-----> "eq" param is true (JEQ) + */ +static int gen_j_eq_64(u8 *buf, u8 rd, u8 rs, bool eq, + u32 curr_off, u32 targ_off) +{ + s32 disp; + u8 len = 0; + + len += arc_cmp_r(BUF(buf, len), REG_HI(rd), REG_HI(rs)); + len += arc_cmpz_r(BUF(buf, len), REG_LO(rd), REG_LO(rs)); + disp = get_displacement(curr_off + len, targ_off); + len += arc_bcc(BUF(buf, len), eq ? CC_equal : CC_unequal, disp); + + return len; +} + +/* + * tst rd_hi, rs_hi + * tst.z rd_lo, rs_lo + * bne @target + */ +static u8 gen_jset_64(u8 *buf, u8 rd, u8 rs, u32 curr_off, u32 targ_off) +{ + u8 len = 0; + s32 disp; + + len += arc_tst_r(BUF(buf, len), REG_HI(rd), REG_HI(rs)); + len += arc_tstz_r(BUF(buf, len), REG_LO(rd), REG_LO(rs)); + disp = get_displacement(curr_off + len, targ_off); + len += arc_bcc(BUF(buf, len), CC_unequal, disp); + + return len; +} + +/* + * Verify if all the jumps for a JITed jcc64 operation are valid, + * by consulting the data stored at "arcv2_64_jccs". + */ +static bool check_jcc_64(u32 curr_off, u32 targ_off, u8 cond) +{ + size_t i; + + if (cond >= ARC_CC_LAST) + return false; + + for (i = 0; i < JCC64_NR_OF_JMPS; i++) { + u32 from, to; + + from = curr_off + arcv2_64_jccs.jit_off[i]; + /* for the 2nd jump, we jump to the end of block. */ + if (i != JCC64_SKIP_JMP) + to = targ_off; + else + to = from + (JCC64_INSNS_TO_END * INSN_len_normal); + /* There is a "cc" in the instruction, so a "near" jump. */ + if (!is_valid_near_disp(get_displacement(from, to))) + return false; + } + + return true; +} + +/* Can the jump from "curr_off" to "targ_off" actually happen? */ +bool check_jmp_64(u32 curr_off, u32 targ_off, u8 cond) +{ + s32 disp; + + switch (cond) { + case ARC_CC_UGT: + case ARC_CC_UGE: + case ARC_CC_ULT: + case ARC_CC_ULE: + case ARC_CC_SGT: + case ARC_CC_SGE: + case ARC_CC_SLT: + case ARC_CC_SLE: + return check_jcc_64(curr_off, targ_off, cond); + case ARC_CC_EQ: + case ARC_CC_NE: + case ARC_CC_SET: + /* + * The "jump" for the JITed BPF_J{SET,EQ,NE} is actually the + * 3rd instruction. See comments of "gen_j{set,_eq}_64()". + */ + curr_off += 2 * INSN_len_normal; + disp = get_displacement(curr_off, targ_off); + /* There is a "cc" field in the issued instruction. */ + return is_valid_near_disp(disp); + case ARC_CC_AL: + disp = get_displacement(curr_off, targ_off); + return is_valid_far_disp(disp); + default: + return false; + } +} + +/* + * The template for the 64-bit jumps with the following BPF conditions + * + * u< u<= u> u>= s< s<= s> s>= + * + * Looks like below: + * + * cmp rd_hi, rs_hi + * b<c1> @target + * b<c2> @end + * cmp rd_lo, rs_lo # if execution reaches here, r{d,s}_hi are equal + * b<c3> @target + * end: + * + * "c1" is the condition that JIT is handling minus the equality part. + * For instance if we have to translate an "unsigned greater or equal", + * then "c1" will be "unsigned greater". We won't know about equality + * until all 64-bits of data (higeher and lower registers) are processed. + * + * "c2" is the counter logic of "c1". For instance, if "c1" is originated + * from "s>", then "c2" would be "s<". Notice that equality doesn't play + * a role here either, because the lower 32 bits are not processed yet. + * + * "c3" is the unsigned version of "c1", no matter if the BPF condition + * was signed or unsigned. An unsigned version is necessary, because the + * MSB of the lower 32 bits does not reflect a sign in the whole 64-bit + * scheme. Otherwise, 64-bit comparisons like + * (0x0000_0000,0x8000_0000) s>= (0x0000_0000,0x0000_0000) + * would yield an incorrect result. Finally, if there is an equality + * check in the BPF condition, it will be reflected in "c3". + * + * You can find all the instances of this template where the + * "arcv2_64_jccs" is getting initialised. + */ +static u8 gen_jcc_64(u8 *buf, u8 rd, u8 rs, u8 cond, + u32 curr_off, u32 targ_off) +{ + s32 disp; + u32 end_off; + const u8 *cc = arcv2_64_jccs.jmp[cond].cond; + u8 len = 0; + + /* cmp rd_hi, rs_hi */ + len += arc_cmp_r(buf, REG_HI(rd), REG_HI(rs)); + + /* b<c1> @target */ + disp = get_displacement(curr_off + len, targ_off); + len += arc_bcc(BUF(buf, len), cc[0], disp); + + /* b<c2> @end */ + end_off = curr_off + len + (JCC64_INSNS_TO_END * INSN_len_normal); + disp = get_displacement(curr_off + len, end_off); + len += arc_bcc(BUF(buf, len), cc[1], disp); + + /* cmp rd_lo, rs_lo */ + len += arc_cmp_r(BUF(buf, len), REG_LO(rd), REG_LO(rs)); + + /* b<c3> @target */ + disp = get_displacement(curr_off + len, targ_off); + len += arc_bcc(BUF(buf, len), cc[2], disp); + + return len; +} + +/* + * This function only applies the necessary logic to make the proper + * translations. All the sanity checks must have already been done + * by calling the check_jmp_64(). + */ +u8 gen_jmp_64(u8 *buf, u8 rd, u8 rs, u8 cond, u32 curr_off, u32 targ_off) +{ + u8 len = 0; + bool eq = false; + s32 disp; + + switch (cond) { + case ARC_CC_AL: + disp = get_displacement(curr_off, targ_off); + len = arc_b(buf, disp); + break; + case ARC_CC_UGT: + case ARC_CC_UGE: + case ARC_CC_ULT: + case ARC_CC_ULE: + case ARC_CC_SGT: + case ARC_CC_SGE: + case ARC_CC_SLT: + case ARC_CC_SLE: + len = gen_jcc_64(buf, rd, rs, cond, curr_off, targ_off); + break; + case ARC_CC_EQ: + eq = true; + fallthrough; + case ARC_CC_NE: + len = gen_j_eq_64(buf, rd, rs, eq, curr_off, targ_off); + break; + case ARC_CC_SET: + len = gen_jset_64(buf, rd, rs, curr_off, targ_off); + break; + default: +#ifdef ARC_BPF_JIT_DEBUG + pr_err("64-bit jump condition is not known."); + BUG(); +#endif + } + return len; +} + +/* + * The condition codes to use when generating JIT instructions + * for 32-bit jumps. + * + * The "ARC_CC_AL" index is not really used by the code, but it + * is here for the sake of completeness. + * + * The "ARC_CC_SET" becomes "CC_unequal" because of the "tst" + * instruction that precedes the conditional branch. + */ +static const u8 arcv2_32_jmps[ARC_CC_LAST] = { + [ARC_CC_UGT] = CC_great_u, + [ARC_CC_UGE] = CC_great_eq_u, + [ARC_CC_ULT] = CC_less_u, + [ARC_CC_ULE] = CC_less_eq_u, + [ARC_CC_SGT] = CC_great_s, + [ARC_CC_SGE] = CC_great_eq_s, + [ARC_CC_SLT] = CC_less_s, + [ARC_CC_SLE] = CC_less_eq_s, + [ARC_CC_AL] = CC_always, + [ARC_CC_EQ] = CC_equal, + [ARC_CC_NE] = CC_unequal, + [ARC_CC_SET] = CC_unequal +}; + +/* Can the jump from "curr_off" to "targ_off" actually happen? */ +bool check_jmp_32(u32 curr_off, u32 targ_off, u8 cond) +{ + u8 addendum; + s32 disp; + + if (cond >= ARC_CC_LAST) + return false; + + /* + * The unconditional jump happens immediately, while the rest + * are either preceded by a "cmp" or "tst" instruction. + */ + addendum = (cond == ARC_CC_AL) ? 0 : INSN_len_normal; + disp = get_displacement(curr_off + addendum, targ_off); + + if (ARC_CC_AL) + return is_valid_far_disp(disp); + else + return is_valid_near_disp(disp); +} + +/* + * The JITed code for 32-bit (conditional) branches: + * + * ARC_CC_AL @target + * b @jit_targ_addr + * + * ARC_CC_SET rd, rs, @target + * tst rd, rs + * bnz @jit_targ_addr + * + * ARC_CC_xx rd, rs, @target + * cmp rd, rs + * b<cc> @jit_targ_addr # cc = arcv2_32_jmps[xx] + */ +u8 gen_jmp_32(u8 *buf, u8 rd, u8 rs, u8 cond, u32 curr_off, u32 targ_off) +{ + s32 disp; + u8 len = 0; + + /* + * Although this must have already been checked by "check_jmp_32()", + * we're not going to risk accessing "arcv2_32_jmps" array without + * the boundary check. + */ + if (cond >= ARC_CC_LAST) { +#ifdef ARC_BPF_JIT_DEBUG + pr_err("32-bit jump condition is not known."); + BUG(); +#endif + return 0; + } + + /* If there is a "condition", issue the "cmp" or "tst" first. */ + if (cond != ARC_CC_AL) { + if (cond == ARC_CC_SET) + len = tst_r32(buf, rd, rs); + else + len = cmp_r32(buf, rd, rs); + /* + * The issued instruction affects the "disp"lacement as + * it alters the "curr_off" by its "len"gth. The "curr_off" + * should always point to the jump instruction. + */ + disp = get_displacement(curr_off + len, targ_off); + len += arc_bcc(BUF(buf, len), arcv2_32_jmps[cond], disp); + } else { + /* The straight forward unconditional jump. */ + disp = get_displacement(curr_off, targ_off); + len = arc_b(buf, disp); + } + + return len; +} + +/* + * Generate code for functions calls. There can be two types of calls: + * + * - Calling another BPF function + * - Calling an in-kernel function which is compiled by ARC gcc + * + * In the later case, we must comply to ARCv2 ABI and handle arguments + * and return values accordingly. + */ +u8 gen_func_call(u8 *buf, ARC_ADDR func_addr, bool external_func) +{ + u8 len = 0; + + /* + * In case of an in-kernel function call, always push the 5th + * argument onto the stack, because that's where the ABI dictates + * it should be found. If the callee doesn't really use it, no harm + * is done. The stack is readjusted either way after the call. + */ + if (external_func) + len += push_r64(BUF(buf, len), BPF_REG_5); + + len += jump_and_link(BUF(buf, len), func_addr); + + if (external_func) + len += arc_add_i(BUF(buf, len), ARC_R_SP, ARC_R_SP, ARG5_SIZE); + + return len; +} diff --git a/arch/arc/net/bpf_jit_core.c b/arch/arc/net/bpf_jit_core.c new file mode 100644 index 0000000000..e3628922c2 --- /dev/null +++ b/arch/arc/net/bpf_jit_core.c @@ -0,0 +1,1425 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * The back-end-agnostic part of Just-In-Time compiler for eBPF bytecode. + * + * Copyright (c) 2024 Synopsys Inc. + * Author: Shahab Vahedi <shahab@synopsys.com> + */ +#include <linux/bug.h> +#include "bpf_jit.h" + +/* + * Check for the return value. A pattern used often in this file. + * There must be a "ret" variable of type "int" in the scope. + */ +#define CHECK_RET(cmd) \ + do { \ + ret = (cmd); \ + if (ret < 0) \ + return ret; \ + } while (0) + +#ifdef ARC_BPF_JIT_DEBUG +/* Dumps bytes in /var/log/messages at KERN_INFO level (4). */ +static void dump_bytes(const u8 *buf, u32 len, const char *header) +{ + u8 line[64]; + size_t i, j; + + pr_info("-----------------[ %s ]-----------------\n", header); + + for (i = 0, j = 0; i < len; i++) { + /* Last input byte? */ + if (i == len - 1) { + j += scnprintf(line + j, 64 - j, "0x%02x", buf[i]); + pr_info("%s\n", line); + break; + } + /* End of line? */ + else if (i % 8 == 7) { + j += scnprintf(line + j, 64 - j, "0x%02x", buf[i]); + pr_info("%s\n", line); + j = 0; + } else { + j += scnprintf(line + j, 64 - j, "0x%02x, ", buf[i]); + } + } +} +#endif /* ARC_BPF_JIT_DEBUG */ + +/********************* JIT context ***********************/ + +/* + * buf: Translated instructions end up here. + * len: The length of whole block in bytes. + * index: The offset at which the _next_ instruction may be put. + */ +struct jit_buffer { + u8 *buf; + u32 len; + u32 index; +}; + +/* + * This is a subset of "struct jit_context" that its information is deemed + * necessary for the next extra pass to come. + * + * bpf_header: Needed to finally lock the region. + * bpf2insn: Used to find the translation for instructions of interest. + * + * Things like "jit.buf" and "jit.len" can be retrieved respectively from + * "prog->bpf_func" and "prog->jited_len". + */ +struct arc_jit_data { + struct bpf_binary_header *bpf_header; + u32 *bpf2insn; +}; + +/* + * The JIT pertinent context that is used by different functions. + * + * prog: The current eBPF program being handled. + * orig_prog: The original eBPF program before any possible change. + * jit: The JIT buffer and its length. + * bpf_header: The JITed program header. "jit.buf" points inside it. + * emit: If set, opcodes are written to memory; else, a dry-run. + * do_zext: If true, 32-bit sub-regs must be zero extended. + * bpf2insn: Maps BPF insn indices to their counterparts in jit.buf. + * bpf2insn_valid: Indicates if "bpf2ins" is populated with the mappings. + * jit_data: A piece of memory to transfer data to the next pass. + * arc_regs_clobbered: Each bit status determines if that arc reg is clobbered. + * save_blink: Whether ARC's "blink" register needs to be saved. + * frame_size: Derived from "prog->aux->stack_depth". + * epilogue_offset: Used by early "return"s in the code to jump here. + * need_extra_pass: A forecast if an "extra_pass" will occur. + * is_extra_pass: Indicates if the current pass is an extra pass. + * user_bpf_prog: True, if VM opcodes come from a real program. + * blinded: True if "constant blinding" step returned a new "prog". + * success: Indicates if the whole JIT went OK. + */ +struct jit_context { + struct bpf_prog *prog; + struct bpf_prog *orig_prog; + struct jit_buffer jit; + struct bpf_binary_header *bpf_header; + bool emit; + bool do_zext; + u32 *bpf2insn; + bool bpf2insn_valid; + struct arc_jit_data *jit_data; + u32 arc_regs_clobbered; + bool save_blink; + u16 frame_size; + u32 epilogue_offset; + bool need_extra_pass; + bool is_extra_pass; + bool user_bpf_prog; + bool blinded; + bool success; +}; + +/* + * If we're in ARC_BPF_JIT_DEBUG mode and the debug level is right, dump the + * input BPF stream. "bpf_jit_dump()" is not fully suited for this purpose. + */ +static void vm_dump(const struct bpf_prog *prog) +{ +#ifdef ARC_BPF_JIT_DEBUG + if (bpf_jit_enable > 1) + dump_bytes((u8 *)prog->insns, 8 * prog->len, " VM "); +#endif +} + +/* + * If the right level of debug is set, dump the bytes. There are 2 variants + * of this function: + * + * 1. Use the standard bpf_jit_dump() which is meant only for JITed code. + * 2. Use the dump_bytes() to match its "vm_dump()" instance. + */ +static void jit_dump(const struct jit_context *ctx) +{ +#ifdef ARC_BPF_JIT_DEBUG + u8 header[8]; +#endif + const int pass = ctx->is_extra_pass ? 2 : 1; + + if (bpf_jit_enable <= 1 || !ctx->prog->jited) + return; + +#ifdef ARC_BPF_JIT_DEBUG + scnprintf(header, sizeof(header), "JIT:%d", pass); + dump_bytes(ctx->jit.buf, ctx->jit.len, header); + pr_info("\n"); +#else + bpf_jit_dump(ctx->prog->len, ctx->jit.len, pass, ctx->jit.buf); +#endif +} + +/* Initialise the context so there's no garbage. */ +static int jit_ctx_init(struct jit_context *ctx, struct bpf_prog *prog) +{ + memset(ctx, 0, sizeof(*ctx)); + + ctx->orig_prog = prog; + + /* If constant blinding was requested but failed, scram. */ + ctx->prog = bpf_jit_blind_constants(prog); + if (IS_ERR(ctx->prog)) + return PTR_ERR(ctx->prog); + ctx->blinded = (ctx->prog != ctx->orig_prog); + + /* If the verifier doesn't zero-extend, then we have to do it. */ + ctx->do_zext = !ctx->prog->aux->verifier_zext; + + ctx->is_extra_pass = ctx->prog->jited; + ctx->user_bpf_prog = ctx->prog->is_func; + + return 0; +} + +/* + * Only after the first iteration of normal pass (the dry-run), + * there are valid offsets in ctx->bpf2insn array. + */ +static inline bool offsets_available(const struct jit_context *ctx) +{ + return ctx->bpf2insn_valid; +} + +/* + * "*mem" should be freed when there is no "extra pass" to come, + * or the compilation terminated abruptly. A few of such memory + * allocations are: ctx->jit_data and ctx->bpf2insn. + */ +static inline void maybe_free(struct jit_context *ctx, void **mem) +{ + if (*mem) { + if (!ctx->success || !ctx->need_extra_pass) { + kfree(*mem); + *mem = NULL; + } + } +} + +/* + * Free memories based on the status of the context. + * + * A note about "bpf_header": On successful runs, "bpf_header" is + * not freed, because "jit.buf", a sub-array of it, is returned as + * the "bpf_func". However, "bpf_header" is lost and nothing points + * to it. This should not cause a leakage, because apparently + * "bpf_header" can be revived by "bpf_jit_binary_hdr()". This is + * how "bpf_jit_free()" in "kernel/bpf/core.c" releases the memory. + */ +static void jit_ctx_cleanup(struct jit_context *ctx) +{ + if (ctx->blinded) { + /* if all went well, release the orig_prog. */ + if (ctx->success) + bpf_jit_prog_release_other(ctx->prog, ctx->orig_prog); + else + bpf_jit_prog_release_other(ctx->orig_prog, ctx->prog); + } + + maybe_free(ctx, (void **)&ctx->bpf2insn); + maybe_free(ctx, (void **)&ctx->jit_data); + + if (!ctx->bpf2insn) + ctx->bpf2insn_valid = false; + + /* Freeing "bpf_header" is enough. "jit.buf" is a sub-array of it. */ + if (!ctx->success && ctx->bpf_header) { + bpf_jit_binary_free(ctx->bpf_header); + ctx->bpf_header = NULL; + ctx->jit.buf = NULL; + ctx->jit.index = 0; + ctx->jit.len = 0; + } + + ctx->emit = false; + ctx->do_zext = false; +} + +/* + * Analyse the register usage and record the frame size. + * The register usage is determined by consulting the back-end. + */ +static void analyze_reg_usage(struct jit_context *ctx) +{ + size_t i; + u32 usage = 0; + const struct bpf_insn *insn = ctx->prog->insnsi; + + for (i = 0; i < ctx->prog->len; i++) { + u8 bpf_reg; + bool call; + + bpf_reg = insn[i].dst_reg; + call = (insn[i].code == (BPF_JMP | BPF_CALL)) ? true : false; + usage |= mask_for_used_regs(bpf_reg, call); + } + + ctx->arc_regs_clobbered = usage; + ctx->frame_size = ctx->prog->aux->stack_depth; +} + +/* Verify that no instruction will be emitted when there is no buffer. */ +static inline int jit_buffer_check(const struct jit_context *ctx) +{ + if (ctx->emit) { + if (!ctx->jit.buf) { + pr_err("bpf-jit: inconsistence state; no " + "buffer to emit instructions.\n"); + return -EINVAL; + } else if (ctx->jit.index > ctx->jit.len) { + pr_err("bpf-jit: estimated JIT length is less " + "than the emitted instructions.\n"); + return -EFAULT; + } + } + return 0; +} + +/* On a dry-run (emit=false), "jit.len" is growing gradually. */ +static inline void jit_buffer_update(struct jit_context *ctx, u32 n) +{ + if (!ctx->emit) + ctx->jit.len += n; + else + ctx->jit.index += n; +} + +/* Based on "emit", determine the address where instructions are emitted. */ +static inline u8 *effective_jit_buf(const struct jit_context *ctx) +{ + return ctx->emit ? (ctx->jit.buf + ctx->jit.index) : NULL; +} + +/* Prologue based on context variables set by "analyze_reg_usage()". */ +static int handle_prologue(struct jit_context *ctx) +{ + int ret; + u8 *buf = effective_jit_buf(ctx); + u32 len = 0; + + CHECK_RET(jit_buffer_check(ctx)); + + len = arc_prologue(buf, ctx->arc_regs_clobbered, ctx->frame_size); + jit_buffer_update(ctx, len); + + return 0; +} + +/* The counter part for "handle_prologue()". */ +static int handle_epilogue(struct jit_context *ctx) +{ + int ret; + u8 *buf = effective_jit_buf(ctx); + u32 len = 0; + + CHECK_RET(jit_buffer_check(ctx)); + + len = arc_epilogue(buf, ctx->arc_regs_clobbered, ctx->frame_size); + jit_buffer_update(ctx, len); + + return 0; +} + +/* Tell which number of the BPF instruction we are dealing with. */ +static inline s32 get_index_for_insn(const struct jit_context *ctx, + const struct bpf_insn *insn) +{ + return (insn - ctx->prog->insnsi); +} + +/* + * In most of the cases, the "offset" is read from "insn->off". However, + * if it is an unconditional BPF_JMP32, then it comes from "insn->imm". + * + * (Courtesy of "cpu=v4" support) + */ +static inline s32 get_offset(const struct bpf_insn *insn) +{ + if ((BPF_CLASS(insn->code) == BPF_JMP32) && + (BPF_OP(insn->code) == BPF_JA)) + return insn->imm; + else + return insn->off; +} + +/* + * Determine to which number of the BPF instruction we're jumping to. + * + * The "offset" is interpreted as the "number" of BPF instructions + * from the _next_ BPF instruction. e.g.: + * + * 4 means 4 instructions after the next insn + * 0 means 0 instructions after the next insn -> fallthrough. + * -1 means 1 instruction before the next insn -> jmp to current insn. + * + * Another way to look at this, "offset" is the number of instructions + * that exist between the current instruction and the target instruction. + * + * It is worth noting that a "mov r,i64", which is 16-byte long, is + * treated as two instructions long, therefore "offset" needn't be + * treated specially for those. Everything is uniform. + */ +static inline s32 get_target_index_for_insn(const struct jit_context *ctx, + const struct bpf_insn *insn) +{ + return (get_index_for_insn(ctx, insn) + 1) + get_offset(insn); +} + +/* Is there an immediate operand encoded in the "insn"? */ +static inline bool has_imm(const struct bpf_insn *insn) +{ + return BPF_SRC(insn->code) == BPF_K; +} + +/* Is the last BPF instruction? */ +static inline bool is_last_insn(const struct bpf_prog *prog, u32 idx) +{ + return idx == (prog->len - 1); +} + +/* + * Invocation of this function, conditionally signals the need for + * an extra pass. The conditions that must be met are: + * + * 1. The current pass itself shouldn't be an extra pass. + * 2. The stream of bytes being JITed must come from a user program. + */ +static inline void set_need_for_extra_pass(struct jit_context *ctx) +{ + if (!ctx->is_extra_pass) + ctx->need_extra_pass = ctx->user_bpf_prog; +} + +/* + * Check if the "size" is valid and then transfer the control to + * the back-end for the swap. + */ +static int handle_swap(u8 *buf, u8 rd, u8 size, u8 endian, + bool force, bool do_zext, u8 *len) +{ + /* Sanity check on the size. */ + switch (size) { + case 16: + case 32: + case 64: + break; + default: + pr_err("bpf-jit: invalid size for swap.\n"); + return -EINVAL; + } + + *len = gen_swap(buf, rd, size, endian, force, do_zext); + + return 0; +} + +/* Checks if the (instruction) index is in valid range. */ +static inline bool check_insn_idx_valid(const struct jit_context *ctx, + const s32 idx) +{ + return (idx >= 0 && idx < ctx->prog->len); +} + +/* + * Decouple the back-end from BPF by converting BPF conditions + * to internal enum. ARC_CC_* start from 0 and are used as index + * to an array. BPF_J* usage must end after this conversion. + */ +static int bpf_cond_to_arc(const u8 op, u8 *arc_cc) +{ + switch (op) { + case BPF_JA: + *arc_cc = ARC_CC_AL; + break; + case BPF_JEQ: + *arc_cc = ARC_CC_EQ; + break; + case BPF_JGT: + *arc_cc = ARC_CC_UGT; + break; + case BPF_JGE: + *arc_cc = ARC_CC_UGE; + break; + case BPF_JSET: + *arc_cc = ARC_CC_SET; + break; + case BPF_JNE: + *arc_cc = ARC_CC_NE; + break; + case BPF_JSGT: + *arc_cc = ARC_CC_SGT; + break; + case BPF_JSGE: + *arc_cc = ARC_CC_SGE; + break; + case BPF_JLT: + *arc_cc = ARC_CC_ULT; + break; + case BPF_JLE: + *arc_cc = ARC_CC_ULE; + break; + case BPF_JSLT: + *arc_cc = ARC_CC_SLT; + break; + case BPF_JSLE: + *arc_cc = ARC_CC_SLE; + break; + default: + pr_err("bpf-jit: can't handle condition 0x%02X\n", op); + return -EINVAL; + } + return 0; +} + +/* + * Check a few things for a supposedly "jump" instruction: + * + * 0. "insn" is a "jump" instruction, but not the "call/exit" variant. + * 1. The current "insn" index is in valid range. + * 2. The index of target instruction is in valid range. + */ +static int check_bpf_jump(const struct jit_context *ctx, + const struct bpf_insn *insn) +{ + const u8 class = BPF_CLASS(insn->code); + const u8 op = BPF_OP(insn->code); + + /* Must be a jmp(32) instruction that is not a "call/exit". */ + if ((class != BPF_JMP && class != BPF_JMP32) || + (op == BPF_CALL || op == BPF_EXIT)) { + pr_err("bpf-jit: not a jump instruction.\n"); + return -EINVAL; + } + + if (!check_insn_idx_valid(ctx, get_index_for_insn(ctx, insn))) { + pr_err("bpf-jit: the bpf jump insn is not in prog.\n"); + return -EINVAL; + } + + if (!check_insn_idx_valid(ctx, get_target_index_for_insn(ctx, insn))) { + pr_err("bpf-jit: bpf jump label is out of range.\n"); + return -EINVAL; + } + + return 0; +} + +/* + * Based on input "insn", consult "ctx->bpf2insn" to get the + * related index (offset) of the translation in JIT stream. + */ +static u32 get_curr_jit_off(const struct jit_context *ctx, + const struct bpf_insn *insn) +{ + const s32 idx = get_index_for_insn(ctx, insn); +#ifdef ARC_BPF_JIT_DEBUG + BUG_ON(!offsets_available(ctx) || !check_insn_idx_valid(ctx, idx)); +#endif + return ctx->bpf2insn[idx]; +} + +/* + * The input "insn" must be a jump instruction. + * + * Based on input "insn", consult "ctx->bpf2insn" to get the + * related JIT index (offset) of "target instruction" that + * "insn" would jump to. + */ +static u32 get_targ_jit_off(const struct jit_context *ctx, + const struct bpf_insn *insn) +{ + const s32 tidx = get_target_index_for_insn(ctx, insn); +#ifdef ARC_BPF_JIT_DEBUG + BUG_ON(!offsets_available(ctx) || !check_insn_idx_valid(ctx, tidx)); +#endif + return ctx->bpf2insn[tidx]; +} + +/* + * This function will return 0 for a feasible jump. + * + * Consult the back-end to check if it finds it feasible to emit + * the necessary instructions based on "cond" and the displacement + * between the "from_off" and the "to_off". + */ +static int feasible_jit_jump(u32 from_off, u32 to_off, u8 cond, bool j32) +{ + int ret = 0; + + if (j32) { + if (!check_jmp_32(from_off, to_off, cond)) + ret = -EFAULT; + } else { + if (!check_jmp_64(from_off, to_off, cond)) + ret = -EFAULT; + } + + if (ret != 0) + pr_err("bpf-jit: the JIT displacement is not OK.\n"); + + return ret; +} + +/* + * This jump handler performs the following steps: + * + * 1. Compute ARC's internal condition code from BPF's + * 2. Determine the bitness of the operation (32 vs. 64) + * 3. Sanity check on BPF stream + * 4. Sanity check on what is supposed to be JIT's displacement + * 5. And finally, emit the necessary instructions + * + * The last two steps are performed through the back-end. + * The value of steps 1 and 2 are necessary inputs for the back-end. + */ +static int handle_jumps(const struct jit_context *ctx, + const struct bpf_insn *insn, + u8 *len) +{ + u8 cond; + int ret = 0; + u8 *buf = effective_jit_buf(ctx); + const bool j32 = (BPF_CLASS(insn->code) == BPF_JMP32) ? true : false; + const u8 rd = insn->dst_reg; + u8 rs = insn->src_reg; + u32 curr_off = 0, targ_off = 0; + + *len = 0; + + /* Map the BPF condition to internal enum. */ + CHECK_RET(bpf_cond_to_arc(BPF_OP(insn->code), &cond)); + + /* Sanity check on the BPF byte stream. */ + CHECK_RET(check_bpf_jump(ctx, insn)); + + /* + * Move the immediate into a temporary register _now_ for 2 reasons: + * + * 1. "gen_jmp_{32,64}()" deal with operands in registers. + * + * 2. The "len" parameter will grow so that the current jit offset + * (curr_off) will have increased to a point where the necessary + * instructions can be inserted by "gen_jmp_{32,64}()". + */ + if (has_imm(insn) && cond != ARC_CC_AL) { + if (j32) { + *len += mov_r32_i32(BUF(buf, *len), JIT_REG_TMP, + insn->imm); + } else { + *len += mov_r64_i32(BUF(buf, *len), JIT_REG_TMP, + insn->imm); + } + rs = JIT_REG_TMP; + } + + /* If the offsets are known, check if the branch can occur. */ + if (offsets_available(ctx)) { + curr_off = get_curr_jit_off(ctx, insn) + *len; + targ_off = get_targ_jit_off(ctx, insn); + + /* Sanity check on the back-end side. */ + CHECK_RET(feasible_jit_jump(curr_off, targ_off, cond, j32)); + } + + if (j32) { + *len += gen_jmp_32(BUF(buf, *len), rd, rs, cond, + curr_off, targ_off); + } else { + *len += gen_jmp_64(BUF(buf, *len), rd, rs, cond, + curr_off, targ_off); + } + + return ret; +} + +/* Jump to translated epilogue address. */ +static int handle_jmp_epilogue(struct jit_context *ctx, + const struct bpf_insn *insn, u8 *len) +{ + u8 *buf = effective_jit_buf(ctx); + u32 curr_off = 0, epi_off = 0; + + /* Check the offset only if the data is available. */ + if (offsets_available(ctx)) { + curr_off = get_curr_jit_off(ctx, insn); + epi_off = ctx->epilogue_offset; + + if (!check_jmp_64(curr_off, epi_off, ARC_CC_AL)) { + pr_err("bpf-jit: epilogue offset is not valid.\n"); + return -EINVAL; + } + } + + /* Jump to "epilogue offset" (rd and rs don't matter). */ + *len = gen_jmp_64(buf, 0, 0, ARC_CC_AL, curr_off, epi_off); + + return 0; +} + +/* Try to get the resolved address and generate the instructions. */ +static int handle_call(struct jit_context *ctx, + const struct bpf_insn *insn, + u8 *len) +{ + int ret; + bool in_kernel_func, fixed = false; + u64 addr = 0; + u8 *buf = effective_jit_buf(ctx); + + ret = bpf_jit_get_func_addr(ctx->prog, insn, ctx->is_extra_pass, + &addr, &fixed); + if (ret < 0) { + pr_err("bpf-jit: can't get the address for call.\n"); + return ret; + } + in_kernel_func = (fixed ? true : false); + + /* No valuable address retrieved (yet). */ + if (!fixed && !addr) + set_need_for_extra_pass(ctx); + + *len = gen_func_call(buf, (ARC_ADDR)addr, in_kernel_func); + + if (insn->src_reg != BPF_PSEUDO_CALL) { + /* Assigning ABI's return reg to JIT's return reg. */ + *len += arc_to_bpf_return(BUF(buf, *len)); + } + + return 0; +} + +/* + * Try to generate instructions for loading a 64-bit immediate. + * These sort of instructions are usually associated with the 64-bit + * relocations: R_BPF_64_64. Therefore, signal the need for an extra + * pass if the circumstances are right. + */ +static int handle_ld_imm64(struct jit_context *ctx, + const struct bpf_insn *insn, + u8 *len) +{ + const s32 idx = get_index_for_insn(ctx, insn); + u8 *buf = effective_jit_buf(ctx); + + /* We're about to consume 2 VM instructions. */ + if (is_last_insn(ctx->prog, idx)) { + pr_err("bpf-jit: need more data for 64-bit immediate.\n"); + return -EINVAL; + } + + *len = mov_r64_i64(buf, insn->dst_reg, insn->imm, (insn + 1)->imm); + + if (bpf_pseudo_func(insn)) + set_need_for_extra_pass(ctx); + + return 0; +} + +/* + * Handles one eBPF instruction at a time. To make this function faster, + * it does not call "jit_buffer_check()". Else, it would call it for every + * instruction. As a result, it should not be invoked directly. Only + * "handle_body()", that has already executed the "check", may call this + * function. + * + * If the "ret" value is negative, something has went wrong. Else, + * it mostly holds the value 0 and rarely 1. Number 1 signals + * the loop in "handle_body()" to skip the next instruction, because + * it has been consumed as part of a 64-bit immediate value. + */ +static int handle_insn(struct jit_context *ctx, u32 idx) +{ + const struct bpf_insn *insn = &ctx->prog->insnsi[idx]; + const u8 code = insn->code; + const u8 dst = insn->dst_reg; + const u8 src = insn->src_reg; + const s16 off = insn->off; + const s32 imm = insn->imm; + u8 *buf = effective_jit_buf(ctx); + u8 len = 0; + int ret = 0; + + switch (code) { + /* dst += src (32-bit) */ + case BPF_ALU | BPF_ADD | BPF_X: + len = add_r32(buf, dst, src); + break; + /* dst += imm (32-bit) */ + case BPF_ALU | BPF_ADD | BPF_K: + len = add_r32_i32(buf, dst, imm); + break; + /* dst -= src (32-bit) */ + case BPF_ALU | BPF_SUB | BPF_X: + len = sub_r32(buf, dst, src); + break; + /* dst -= imm (32-bit) */ + case BPF_ALU | BPF_SUB | BPF_K: + len = sub_r32_i32(buf, dst, imm); + break; + /* dst = -dst (32-bit) */ + case BPF_ALU | BPF_NEG: + len = neg_r32(buf, dst); + break; + /* dst *= src (32-bit) */ + case BPF_ALU | BPF_MUL | BPF_X: + len = mul_r32(buf, dst, src); + break; + /* dst *= imm (32-bit) */ + case BPF_ALU | BPF_MUL | BPF_K: + len = mul_r32_i32(buf, dst, imm); + break; + /* dst /= src (32-bit) */ + case BPF_ALU | BPF_DIV | BPF_X: + len = div_r32(buf, dst, src, off == 1); + break; + /* dst /= imm (32-bit) */ + case BPF_ALU | BPF_DIV | BPF_K: + len = div_r32_i32(buf, dst, imm, off == 1); + break; + /* dst %= src (32-bit) */ + case BPF_ALU | BPF_MOD | BPF_X: + len = mod_r32(buf, dst, src, off == 1); + break; + /* dst %= imm (32-bit) */ + case BPF_ALU | BPF_MOD | BPF_K: + len = mod_r32_i32(buf, dst, imm, off == 1); + break; + /* dst &= src (32-bit) */ + case BPF_ALU | BPF_AND | BPF_X: + len = and_r32(buf, dst, src); + break; + /* dst &= imm (32-bit) */ + case BPF_ALU | BPF_AND | BPF_K: + len = and_r32_i32(buf, dst, imm); + break; + /* dst |= src (32-bit) */ + case BPF_ALU | BPF_OR | BPF_X: + len = or_r32(buf, dst, src); + break; + /* dst |= imm (32-bit) */ + case BPF_ALU | BPF_OR | BPF_K: + len = or_r32_i32(buf, dst, imm); + break; + /* dst ^= src (32-bit) */ + case BPF_ALU | BPF_XOR | BPF_X: + len = xor_r32(buf, dst, src); + break; + /* dst ^= imm (32-bit) */ + case BPF_ALU | BPF_XOR | BPF_K: + len = xor_r32_i32(buf, dst, imm); + break; + /* dst <<= src (32-bit) */ + case BPF_ALU | BPF_LSH | BPF_X: + len = lsh_r32(buf, dst, src); + break; + /* dst <<= imm (32-bit) */ + case BPF_ALU | BPF_LSH | BPF_K: + len = lsh_r32_i32(buf, dst, imm); + break; + /* dst >>= src (32-bit) [unsigned] */ + case BPF_ALU | BPF_RSH | BPF_X: + len = rsh_r32(buf, dst, src); + break; + /* dst >>= imm (32-bit) [unsigned] */ + case BPF_ALU | BPF_RSH | BPF_K: + len = rsh_r32_i32(buf, dst, imm); + break; + /* dst >>= src (32-bit) [signed] */ + case BPF_ALU | BPF_ARSH | BPF_X: + len = arsh_r32(buf, dst, src); + break; + /* dst >>= imm (32-bit) [signed] */ + case BPF_ALU | BPF_ARSH | BPF_K: + len = arsh_r32_i32(buf, dst, imm); + break; + /* dst = src (32-bit) */ + case BPF_ALU | BPF_MOV | BPF_X: + len = mov_r32(buf, dst, src, (u8)off); + break; + /* dst = imm32 (32-bit) */ + case BPF_ALU | BPF_MOV | BPF_K: + len = mov_r32_i32(buf, dst, imm); + break; + /* dst = swap(dst) */ + case BPF_ALU | BPF_END | BPF_FROM_LE: + case BPF_ALU | BPF_END | BPF_FROM_BE: + case BPF_ALU64 | BPF_END | BPF_FROM_LE: { + CHECK_RET(handle_swap(buf, dst, imm, BPF_SRC(code), + BPF_CLASS(code) == BPF_ALU64, + ctx->do_zext, &len)); + break; + } + /* dst += src (64-bit) */ + case BPF_ALU64 | BPF_ADD | BPF_X: + len = add_r64(buf, dst, src); + break; + /* dst += imm32 (64-bit) */ + case BPF_ALU64 | BPF_ADD | BPF_K: + len = add_r64_i32(buf, dst, imm); + break; + /* dst -= src (64-bit) */ + case BPF_ALU64 | BPF_SUB | BPF_X: + len = sub_r64(buf, dst, src); + break; + /* dst -= imm32 (64-bit) */ + case BPF_ALU64 | BPF_SUB | BPF_K: + len = sub_r64_i32(buf, dst, imm); + break; + /* dst = -dst (64-bit) */ + case BPF_ALU64 | BPF_NEG: + len = neg_r64(buf, dst); + break; + /* dst *= src (64-bit) */ + case BPF_ALU64 | BPF_MUL | BPF_X: + len = mul_r64(buf, dst, src); + break; + /* dst *= imm32 (64-bit) */ + case BPF_ALU64 | BPF_MUL | BPF_K: + len = mul_r64_i32(buf, dst, imm); + break; + /* dst &= src (64-bit) */ + case BPF_ALU64 | BPF_AND | BPF_X: + len = and_r64(buf, dst, src); + break; + /* dst &= imm32 (64-bit) */ + case BPF_ALU64 | BPF_AND | BPF_K: + len = and_r64_i32(buf, dst, imm); + break; + /* dst |= src (64-bit) */ + case BPF_ALU64 | BPF_OR | BPF_X: + len = or_r64(buf, dst, src); + break; + /* dst |= imm32 (64-bit) */ + case BPF_ALU64 | BPF_OR | BPF_K: + len = or_r64_i32(buf, dst, imm); + break; + /* dst ^= src (64-bit) */ + case BPF_ALU64 | BPF_XOR | BPF_X: + len = xor_r64(buf, dst, src); + break; + /* dst ^= imm32 (64-bit) */ + case BPF_ALU64 | BPF_XOR | BPF_K: + len = xor_r64_i32(buf, dst, imm); + break; + /* dst <<= src (64-bit) */ + case BPF_ALU64 | BPF_LSH | BPF_X: + len = lsh_r64(buf, dst, src); + break; + /* dst <<= imm32 (64-bit) */ + case BPF_ALU64 | BPF_LSH | BPF_K: + len = lsh_r64_i32(buf, dst, imm); + break; + /* dst >>= src (64-bit) [unsigned] */ + case BPF_ALU64 | BPF_RSH | BPF_X: + len = rsh_r64(buf, dst, src); + break; + /* dst >>= imm32 (64-bit) [unsigned] */ + case BPF_ALU64 | BPF_RSH | BPF_K: + len = rsh_r64_i32(buf, dst, imm); + break; + /* dst >>= src (64-bit) [signed] */ + case BPF_ALU64 | BPF_ARSH | BPF_X: + len = arsh_r64(buf, dst, src); + break; + /* dst >>= imm32 (64-bit) [signed] */ + case BPF_ALU64 | BPF_ARSH | BPF_K: + len = arsh_r64_i32(buf, dst, imm); + break; + /* dst = src (64-bit) */ + case BPF_ALU64 | BPF_MOV | BPF_X: + len = mov_r64(buf, dst, src, (u8)off); + break; + /* dst = imm32 (sign extend to 64-bit) */ + case BPF_ALU64 | BPF_MOV | BPF_K: + len = mov_r64_i32(buf, dst, imm); + break; + /* dst = imm64 */ + case BPF_LD | BPF_DW | BPF_IMM: + CHECK_RET(handle_ld_imm64(ctx, insn, &len)); + /* Tell the loop to skip the next instruction. */ + ret = 1; + break; + /* dst = *(size *)(src + off) */ + case BPF_LDX | BPF_MEM | BPF_W: + case BPF_LDX | BPF_MEM | BPF_H: + case BPF_LDX | BPF_MEM | BPF_B: + case BPF_LDX | BPF_MEM | BPF_DW: + len = load_r(buf, dst, src, off, BPF_SIZE(code), false); + break; + case BPF_LDX | BPF_MEMSX | BPF_W: + case BPF_LDX | BPF_MEMSX | BPF_H: + case BPF_LDX | BPF_MEMSX | BPF_B: + len = load_r(buf, dst, src, off, BPF_SIZE(code), true); + break; + /* *(size *)(dst + off) = src */ + case BPF_STX | BPF_MEM | BPF_W: + case BPF_STX | BPF_MEM | BPF_H: + case BPF_STX | BPF_MEM | BPF_B: + case BPF_STX | BPF_MEM | BPF_DW: + len = store_r(buf, src, dst, off, BPF_SIZE(code)); + break; + case BPF_ST | BPF_MEM | BPF_W: + case BPF_ST | BPF_MEM | BPF_H: + case BPF_ST | BPF_MEM | BPF_B: + case BPF_ST | BPF_MEM | BPF_DW: + len = store_i(buf, imm, dst, off, BPF_SIZE(code)); + break; + case BPF_JMP | BPF_JA: + case BPF_JMP | BPF_JEQ | BPF_X: + case BPF_JMP | BPF_JEQ | BPF_K: + case BPF_JMP | BPF_JNE | BPF_X: + case BPF_JMP | BPF_JNE | BPF_K: + case BPF_JMP | BPF_JSET | BPF_X: + case BPF_JMP | BPF_JSET | BPF_K: + case BPF_JMP | BPF_JGT | BPF_X: + case BPF_JMP | BPF_JGT | BPF_K: + case BPF_JMP | BPF_JGE | BPF_X: + case BPF_JMP | BPF_JGE | BPF_K: + case BPF_JMP | BPF_JSGT | BPF_X: + case BPF_JMP | BPF_JSGT | BPF_K: + case BPF_JMP | BPF_JSGE | BPF_X: + case BPF_JMP | BPF_JSGE | BPF_K: + case BPF_JMP | BPF_JLT | BPF_X: + case BPF_JMP | BPF_JLT | BPF_K: + case BPF_JMP | BPF_JLE | BPF_X: + case BPF_JMP | BPF_JLE | BPF_K: + case BPF_JMP | BPF_JSLT | BPF_X: + case BPF_JMP | BPF_JSLT | BPF_K: + case BPF_JMP | BPF_JSLE | BPF_X: + case BPF_JMP | BPF_JSLE | BPF_K: + case BPF_JMP32 | BPF_JA: + case BPF_JMP32 | BPF_JEQ | BPF_X: + case BPF_JMP32 | BPF_JEQ | BPF_K: + case BPF_JMP32 | BPF_JNE | BPF_X: + case BPF_JMP32 | BPF_JNE | BPF_K: + case BPF_JMP32 | BPF_JSET | BPF_X: + case BPF_JMP32 | BPF_JSET | BPF_K: + case BPF_JMP32 | BPF_JGT | BPF_X: + case BPF_JMP32 | BPF_JGT | BPF_K: + case BPF_JMP32 | BPF_JGE | BPF_X: + case BPF_JMP32 | BPF_JGE | BPF_K: + case BPF_JMP32 | BPF_JSGT | BPF_X: + case BPF_JMP32 | BPF_JSGT | BPF_K: + case BPF_JMP32 | BPF_JSGE | BPF_X: + case BPF_JMP32 | BPF_JSGE | BPF_K: + case BPF_JMP32 | BPF_JLT | BPF_X: + case BPF_JMP32 | BPF_JLT | BPF_K: + case BPF_JMP32 | BPF_JLE | BPF_X: + case BPF_JMP32 | BPF_JLE | BPF_K: + case BPF_JMP32 | BPF_JSLT | BPF_X: + case BPF_JMP32 | BPF_JSLT | BPF_K: + case BPF_JMP32 | BPF_JSLE | BPF_X: + case BPF_JMP32 | BPF_JSLE | BPF_K: + CHECK_RET(handle_jumps(ctx, insn, &len)); + break; + case BPF_JMP | BPF_CALL: + CHECK_RET(handle_call(ctx, insn, &len)); + break; + + case BPF_JMP | BPF_EXIT: + /* If this is the last instruction, epilogue will follow. */ + if (is_last_insn(ctx->prog, idx)) + break; + CHECK_RET(handle_jmp_epilogue(ctx, insn, &len)); + break; + default: + pr_err("bpf-jit: can't handle instruction code 0x%02X\n", code); + return -EOPNOTSUPP; + } + + if (BPF_CLASS(code) == BPF_ALU) { + /* + * Skip the "swap" instructions. Even 64-bit swaps are of type + * BPF_ALU (and not BPF_ALU64). Therefore, for the swaps, one + * has to look at the "size" of the operations rather than the + * ALU type. "gen_swap()" specifically takes care of that. + */ + if (BPF_OP(code) != BPF_END && ctx->do_zext) + len += zext(BUF(buf, len), dst); + } + + jit_buffer_update(ctx, len); + + return ret; +} + +static int handle_body(struct jit_context *ctx) +{ + int ret; + bool populate_bpf2insn = false; + const struct bpf_prog *prog = ctx->prog; + + CHECK_RET(jit_buffer_check(ctx)); + + /* + * Record the mapping for the instructions during the dry-run. + * Doing it this way allows us to have the mapping ready for + * the jump instructions during the real compilation phase. + */ + if (!ctx->emit) + populate_bpf2insn = true; + + for (u32 i = 0; i < prog->len; i++) { + /* During the dry-run, jit.len grows gradually per BPF insn. */ + if (populate_bpf2insn) + ctx->bpf2insn[i] = ctx->jit.len; + + CHECK_RET(handle_insn(ctx, i)); + if (ret > 0) { + /* "ret" is 1 if two (64-bit) chunks were consumed. */ + ctx->bpf2insn[i + 1] = ctx->bpf2insn[i]; + i++; + } + } + + /* If bpf2insn had to be populated, then it is done at this point. */ + if (populate_bpf2insn) + ctx->bpf2insn_valid = true; + + return 0; +} + +/* + * Initialize the memory with "unimp_s" which is the mnemonic for + * "unimplemented" instruction and always raises an exception. + * + * The instruction is 2 bytes. If "size" is odd, there is not much + * that can be done about the last byte in "area". Because, the + * CPU always fetches instructions in two bytes. Therefore, the + * byte beyond the last one is going to accompany it during a + * possible fetch. In the most likely case of a little endian + * system, that beyond-byte will become the major opcode and + * we have no control over its initialisation. + */ +static void fill_ill_insn(void *area, unsigned int size) +{ + const u16 unimp_s = 0x79e0; + + if (size & 1) { + *((u8 *)area + (size - 1)) = 0xff; + size -= 1; + } + + memset16(area, unimp_s, size >> 1); +} + +/* Piece of memory that can be allocated at the beginning of jit_prepare(). */ +static int jit_prepare_early_mem_alloc(struct jit_context *ctx) +{ + ctx->bpf2insn = kcalloc(ctx->prog->len, sizeof(ctx->jit.len), + GFP_KERNEL); + + if (!ctx->bpf2insn) { + pr_err("bpf-jit: could not allocate memory for " + "mapping of the instructions.\n"); + return -ENOMEM; + } + + return 0; +} + +/* + * Memory allocations that rely on parameters known at the end of + * jit_prepare(). + */ +static int jit_prepare_final_mem_alloc(struct jit_context *ctx) +{ + const size_t alignment = sizeof(u32); + + ctx->bpf_header = bpf_jit_binary_alloc(ctx->jit.len, &ctx->jit.buf, + alignment, fill_ill_insn); + if (!ctx->bpf_header) { + pr_err("bpf-jit: could not allocate memory for translation.\n"); + return -ENOMEM; + } + + if (ctx->need_extra_pass) { + ctx->jit_data = kzalloc(sizeof(*ctx->jit_data), GFP_KERNEL); + if (!ctx->jit_data) + return -ENOMEM; + } + + return 0; +} + +/* + * The first phase of the translation without actually emitting any + * instruction. It helps in getting a forecast on some aspects, such + * as the length of the whole program or where the epilogue starts. + * + * Whenever the necessary parameters are known, memories are allocated. + */ +static int jit_prepare(struct jit_context *ctx) +{ + int ret; + + /* Dry run. */ + ctx->emit = false; + + CHECK_RET(jit_prepare_early_mem_alloc(ctx)); + + /* Get the length of prologue section after some register analysis. */ + analyze_reg_usage(ctx); + CHECK_RET(handle_prologue(ctx)); + + CHECK_RET(handle_body(ctx)); + + /* Record at which offset epilogue begins. */ + ctx->epilogue_offset = ctx->jit.len; + + /* Process the epilogue section now. */ + CHECK_RET(handle_epilogue(ctx)); + + CHECK_RET(jit_prepare_final_mem_alloc(ctx)); + + return 0; +} + +/* + * jit_compile() is the real compilation phase. jit_prepare() is + * invoked before jit_compile() as a dry-run to make sure everything + * will go OK and allocate the necessary memory. + * + * In the end, jit_compile() checks if it has produced the same number + * of instructions as jit_prepare() would. + */ +static int jit_compile(struct jit_context *ctx) +{ + int ret; + + /* Let there be code. */ + ctx->emit = true; + + CHECK_RET(handle_prologue(ctx)); + + CHECK_RET(handle_body(ctx)); + + CHECK_RET(handle_epilogue(ctx)); + + if (ctx->jit.index != ctx->jit.len) { + pr_err("bpf-jit: divergence between the phases; " + "%u vs. %u (bytes).\n", + ctx->jit.len, ctx->jit.index); + return -EFAULT; + } + + return 0; +} + +/* + * Calling this function implies a successful JIT. A successful + * translation is signaled by setting the right parameters: + * + * prog->jited=1, prog->jited_len=..., prog->bpf_func=... + */ +static int jit_finalize(struct jit_context *ctx) +{ + struct bpf_prog *prog = ctx->prog; + + /* We're going to need this information for the "do_extra_pass()". */ + if (ctx->need_extra_pass) { + ctx->jit_data->bpf_header = ctx->bpf_header; + ctx->jit_data->bpf2insn = ctx->bpf2insn; + prog->aux->jit_data = (void *)ctx->jit_data; + } else { + /* + * If things seem finalised, then mark the JITed memory + * as R-X and flush it. + */ + if (bpf_jit_binary_lock_ro(ctx->bpf_header)) { + pr_err("bpf-jit: Could not lock the JIT memory.\n"); + return -EFAULT; + } + flush_icache_range((unsigned long)ctx->bpf_header, + (unsigned long) + BUF(ctx->jit.buf, ctx->jit.len)); + prog->aux->jit_data = NULL; + bpf_prog_fill_jited_linfo(prog, ctx->bpf2insn); + } + + ctx->success = true; + prog->bpf_func = (void *)ctx->jit.buf; + prog->jited_len = ctx->jit.len; + prog->jited = 1; + + jit_ctx_cleanup(ctx); + jit_dump(ctx); + + return 0; +} + +/* + * A lenient verification for the existence of JIT context in "prog". + * Apparently the JIT internals, namely jit_subprogs() in bpf/verifier.c, + * may request for a second compilation although nothing needs to be done. + */ +static inline int check_jit_context(const struct bpf_prog *prog) +{ + if (!prog->aux->jit_data) { + pr_notice("bpf-jit: no jit data for the extra pass.\n"); + return 1; + } else { + return 0; + } +} + +/* Reuse the previous pass's data. */ +static int jit_resume_context(struct jit_context *ctx) +{ + struct arc_jit_data *jdata = + (struct arc_jit_data *)ctx->prog->aux->jit_data; + + if (!jdata) { + pr_err("bpf-jit: no jit data for the extra pass.\n"); + return -EINVAL; + } + + ctx->jit.buf = (u8 *)ctx->prog->bpf_func; + ctx->jit.len = ctx->prog->jited_len; + ctx->bpf_header = jdata->bpf_header; + ctx->bpf2insn = (u32 *)jdata->bpf2insn; + ctx->bpf2insn_valid = ctx->bpf2insn ? true : false; + ctx->jit_data = jdata; + + return 0; +} + +/* + * Patch in the new addresses. The instructions of interest are: + * + * - call + * - ld r64, imm64 + * + * For "call"s, it resolves the addresses one more time through the + * handle_call(). + * + * For 64-bit immediate loads, it just retranslates them, because the BPF + * core in kernel might have changed the value since the normal pass. + */ +static int jit_patch_relocations(struct jit_context *ctx) +{ + const u8 bpf_opc_call = BPF_JMP | BPF_CALL; + const u8 bpf_opc_ldi64 = BPF_LD | BPF_DW | BPF_IMM; + const struct bpf_prog *prog = ctx->prog; + int ret; + + ctx->emit = true; + for (u32 i = 0; i < prog->len; i++) { + const struct bpf_insn *insn = &prog->insnsi[i]; + u8 dummy; + /* + * Adjust "ctx.jit.index", so "gen_*()" functions below + * can use it for their output addresses. + */ + ctx->jit.index = ctx->bpf2insn[i]; + + if (insn->code == bpf_opc_call) { + CHECK_RET(handle_call(ctx, insn, &dummy)); + } else if (insn->code == bpf_opc_ldi64) { + CHECK_RET(handle_ld_imm64(ctx, insn, &dummy)); + /* Skip the next instruction. */ + ++i; + } + } + return 0; +} + +/* + * A normal pass that involves a "dry-run" phase, jit_prepare(), + * to get the necessary data for the real compilation phase, + * jit_compile(). + */ +static struct bpf_prog *do_normal_pass(struct bpf_prog *prog) +{ + struct jit_context ctx; + + /* Bail out if JIT is disabled. */ + if (!prog->jit_requested) + return prog; + + if (jit_ctx_init(&ctx, prog)) { + jit_ctx_cleanup(&ctx); + return prog; + } + + /* Get the lengths and allocate buffer. */ + if (jit_prepare(&ctx)) { + jit_ctx_cleanup(&ctx); + return prog; + } + + if (jit_compile(&ctx)) { + jit_ctx_cleanup(&ctx); + return prog; + } + + if (jit_finalize(&ctx)) { + jit_ctx_cleanup(&ctx); + return prog; + } + + return ctx.prog; +} + +/* + * If there are multi-function BPF programs that call each other, + * their translated addresses are not known all at once. Therefore, + * an extra pass is needed to consult the bpf_jit_get_func_addr() + * again to get the newly translated addresses in order to resolve + * the "call"s. + */ +static struct bpf_prog *do_extra_pass(struct bpf_prog *prog) +{ + struct jit_context ctx; + + /* Skip if there's no context to resume from. */ + if (check_jit_context(prog)) + return prog; + + if (jit_ctx_init(&ctx, prog)) { + jit_ctx_cleanup(&ctx); + return prog; + } + + if (jit_resume_context(&ctx)) { + jit_ctx_cleanup(&ctx); + return prog; + } + + if (jit_patch_relocations(&ctx)) { + jit_ctx_cleanup(&ctx); + return prog; + } + + if (jit_finalize(&ctx)) { + jit_ctx_cleanup(&ctx); + return prog; + } + + return ctx.prog; +} + +/* + * This function may be invoked twice for the same stream of BPF + * instructions. The "extra pass" happens, when there are + * (re)locations involved that their addresses are not known + * during the first run. + */ +struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) +{ + vm_dump(prog); + + /* Was this program already translated? */ + if (!prog->jited) + return do_normal_pass(prog); + else + return do_extra_pass(prog); + + return prog; +} |