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-rw-r--r--arch/arm64/net/bpf_jit_comp.c1162
1 files changed, 1162 insertions, 0 deletions
diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
new file mode 100644
index 000000000..18627cbd6
--- /dev/null
+++ b/arch/arm64/net/bpf_jit_comp.c
@@ -0,0 +1,1162 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * BPF JIT compiler for ARM64
+ *
+ * Copyright (C) 2014-2016 Zi Shen Lim <zlim.lnx@gmail.com>
+ */
+
+#define pr_fmt(fmt) "bpf_jit: " fmt
+
+#include <linux/bitfield.h>
+#include <linux/bpf.h>
+#include <linux/filter.h>
+#include <linux/printk.h>
+#include <linux/slab.h>
+
+#include <asm/byteorder.h>
+#include <asm/cacheflush.h>
+#include <asm/debug-monitors.h>
+#include <asm/set_memory.h>
+
+#include "bpf_jit.h"
+
+#define TMP_REG_1 (MAX_BPF_JIT_REG + 0)
+#define TMP_REG_2 (MAX_BPF_JIT_REG + 1)
+#define TCALL_CNT (MAX_BPF_JIT_REG + 2)
+#define TMP_REG_3 (MAX_BPF_JIT_REG + 3)
+
+/* Map BPF registers to A64 registers */
+static const int bpf2a64[] = {
+ /* return value from in-kernel function, and exit value from eBPF */
+ [BPF_REG_0] = A64_R(7),
+ /* arguments from eBPF program to in-kernel function */
+ [BPF_REG_1] = A64_R(0),
+ [BPF_REG_2] = A64_R(1),
+ [BPF_REG_3] = A64_R(2),
+ [BPF_REG_4] = A64_R(3),
+ [BPF_REG_5] = A64_R(4),
+ /* callee saved registers that in-kernel function will preserve */
+ [BPF_REG_6] = A64_R(19),
+ [BPF_REG_7] = A64_R(20),
+ [BPF_REG_8] = A64_R(21),
+ [BPF_REG_9] = A64_R(22),
+ /* read-only frame pointer to access stack */
+ [BPF_REG_FP] = A64_R(25),
+ /* temporary registers for internal BPF JIT */
+ [TMP_REG_1] = A64_R(10),
+ [TMP_REG_2] = A64_R(11),
+ [TMP_REG_3] = A64_R(12),
+ /* tail_call_cnt */
+ [TCALL_CNT] = A64_R(26),
+ /* temporary register for blinding constants */
+ [BPF_REG_AX] = A64_R(9),
+};
+
+struct jit_ctx {
+ const struct bpf_prog *prog;
+ int idx;
+ int epilogue_offset;
+ int *offset;
+ int exentry_idx;
+ __le32 *image;
+ u32 stack_size;
+};
+
+static inline void emit(const u32 insn, struct jit_ctx *ctx)
+{
+ if (ctx->image != NULL)
+ ctx->image[ctx->idx] = cpu_to_le32(insn);
+
+ ctx->idx++;
+}
+
+static inline void emit_a64_mov_i(const int is64, const int reg,
+ const s32 val, struct jit_ctx *ctx)
+{
+ u16 hi = val >> 16;
+ u16 lo = val & 0xffff;
+
+ if (hi & 0x8000) {
+ if (hi == 0xffff) {
+ emit(A64_MOVN(is64, reg, (u16)~lo, 0), ctx);
+ } else {
+ emit(A64_MOVN(is64, reg, (u16)~hi, 16), ctx);
+ if (lo != 0xffff)
+ emit(A64_MOVK(is64, reg, lo, 0), ctx);
+ }
+ } else {
+ emit(A64_MOVZ(is64, reg, lo, 0), ctx);
+ if (hi)
+ emit(A64_MOVK(is64, reg, hi, 16), ctx);
+ }
+}
+
+static int i64_i16_blocks(const u64 val, bool inverse)
+{
+ return (((val >> 0) & 0xffff) != (inverse ? 0xffff : 0x0000)) +
+ (((val >> 16) & 0xffff) != (inverse ? 0xffff : 0x0000)) +
+ (((val >> 32) & 0xffff) != (inverse ? 0xffff : 0x0000)) +
+ (((val >> 48) & 0xffff) != (inverse ? 0xffff : 0x0000));
+}
+
+static inline void emit_a64_mov_i64(const int reg, const u64 val,
+ struct jit_ctx *ctx)
+{
+ u64 nrm_tmp = val, rev_tmp = ~val;
+ bool inverse;
+ int shift;
+
+ if (!(nrm_tmp >> 32))
+ return emit_a64_mov_i(0, reg, (u32)val, ctx);
+
+ inverse = i64_i16_blocks(nrm_tmp, true) < i64_i16_blocks(nrm_tmp, false);
+ shift = max(round_down((inverse ? (fls64(rev_tmp) - 1) :
+ (fls64(nrm_tmp) - 1)), 16), 0);
+ if (inverse)
+ emit(A64_MOVN(1, reg, (rev_tmp >> shift) & 0xffff, shift), ctx);
+ else
+ emit(A64_MOVZ(1, reg, (nrm_tmp >> shift) & 0xffff, shift), ctx);
+ shift -= 16;
+ while (shift >= 0) {
+ if (((nrm_tmp >> shift) & 0xffff) != (inverse ? 0xffff : 0x0000))
+ emit(A64_MOVK(1, reg, (nrm_tmp >> shift) & 0xffff, shift), ctx);
+ shift -= 16;
+ }
+}
+
+/*
+ * Kernel addresses in the vmalloc space use at most 48 bits, and the
+ * remaining bits are guaranteed to be 0x1. So we can compose the address
+ * with a fixed length movn/movk/movk sequence.
+ */
+static inline void emit_addr_mov_i64(const int reg, const u64 val,
+ struct jit_ctx *ctx)
+{
+ u64 tmp = val;
+ int shift = 0;
+
+ emit(A64_MOVN(1, reg, ~tmp & 0xffff, shift), ctx);
+ while (shift < 32) {
+ tmp >>= 16;
+ shift += 16;
+ emit(A64_MOVK(1, reg, tmp & 0xffff, shift), ctx);
+ }
+}
+
+static inline int bpf2a64_offset(int bpf_insn, int off,
+ const struct jit_ctx *ctx)
+{
+ /* BPF JMP offset is relative to the next instruction */
+ bpf_insn++;
+ /*
+ * Whereas arm64 branch instructions encode the offset
+ * from the branch itself, so we must subtract 1 from the
+ * instruction offset.
+ */
+ return ctx->offset[bpf_insn + off] - (ctx->offset[bpf_insn] - 1);
+}
+
+static void jit_fill_hole(void *area, unsigned int size)
+{
+ __le32 *ptr;
+ /* We are guaranteed to have aligned memory. */
+ for (ptr = area; size >= sizeof(u32); size -= sizeof(u32))
+ *ptr++ = cpu_to_le32(AARCH64_BREAK_FAULT);
+}
+
+static inline int epilogue_offset(const struct jit_ctx *ctx)
+{
+ int to = ctx->epilogue_offset;
+ int from = ctx->idx;
+
+ return to - from;
+}
+
+static bool is_addsub_imm(u32 imm)
+{
+ /* Either imm12 or shifted imm12. */
+ return !(imm & ~0xfff) || !(imm & ~0xfff000);
+}
+
+/* Stack must be multiples of 16B */
+#define STACK_ALIGN(sz) (((sz) + 15) & ~15)
+
+/* Tail call offset to jump into */
+#if IS_ENABLED(CONFIG_ARM64_BTI_KERNEL)
+#define PROLOGUE_OFFSET 8
+#else
+#define PROLOGUE_OFFSET 7
+#endif
+
+static int build_prologue(struct jit_ctx *ctx, bool ebpf_from_cbpf)
+{
+ const struct bpf_prog *prog = ctx->prog;
+ const u8 r6 = bpf2a64[BPF_REG_6];
+ const u8 r7 = bpf2a64[BPF_REG_7];
+ const u8 r8 = bpf2a64[BPF_REG_8];
+ const u8 r9 = bpf2a64[BPF_REG_9];
+ const u8 fp = bpf2a64[BPF_REG_FP];
+ const u8 tcc = bpf2a64[TCALL_CNT];
+ const int idx0 = ctx->idx;
+ int cur_offset;
+
+ /*
+ * BPF prog stack layout
+ *
+ * high
+ * original A64_SP => 0:+-----+ BPF prologue
+ * |FP/LR|
+ * current A64_FP => -16:+-----+
+ * | ... | callee saved registers
+ * BPF fp register => -64:+-----+ <= (BPF_FP)
+ * | |
+ * | ... | BPF prog stack
+ * | |
+ * +-----+ <= (BPF_FP - prog->aux->stack_depth)
+ * |RSVD | padding
+ * current A64_SP => +-----+ <= (BPF_FP - ctx->stack_size)
+ * | |
+ * | ... | Function call stack
+ * | |
+ * +-----+
+ * low
+ *
+ */
+
+ /* BTI landing pad */
+ if (IS_ENABLED(CONFIG_ARM64_BTI_KERNEL))
+ emit(A64_BTI_C, ctx);
+
+ /* Save FP and LR registers to stay align with ARM64 AAPCS */
+ emit(A64_PUSH(A64_FP, A64_LR, A64_SP), ctx);
+ emit(A64_MOV(1, A64_FP, A64_SP), ctx);
+
+ /* Save callee-saved registers */
+ emit(A64_PUSH(r6, r7, A64_SP), ctx);
+ emit(A64_PUSH(r8, r9, A64_SP), ctx);
+ emit(A64_PUSH(fp, tcc, A64_SP), ctx);
+
+ /* Set up BPF prog stack base register */
+ emit(A64_MOV(1, fp, A64_SP), ctx);
+
+ if (!ebpf_from_cbpf) {
+ /* Initialize tail_call_cnt */
+ emit(A64_MOVZ(1, tcc, 0, 0), ctx);
+
+ cur_offset = ctx->idx - idx0;
+ if (cur_offset != PROLOGUE_OFFSET) {
+ pr_err_once("PROLOGUE_OFFSET = %d, expected %d!\n",
+ cur_offset, PROLOGUE_OFFSET);
+ return -1;
+ }
+
+ /* BTI landing pad for the tail call, done with a BR */
+ if (IS_ENABLED(CONFIG_ARM64_BTI_KERNEL))
+ emit(A64_BTI_J, ctx);
+ }
+
+ ctx->stack_size = STACK_ALIGN(prog->aux->stack_depth);
+
+ /* Set up function call stack */
+ emit(A64_SUB_I(1, A64_SP, A64_SP, ctx->stack_size), ctx);
+ return 0;
+}
+
+static int out_offset = -1; /* initialized on the first pass of build_body() */
+static int emit_bpf_tail_call(struct jit_ctx *ctx)
+{
+ /* bpf_tail_call(void *prog_ctx, struct bpf_array *array, u64 index) */
+ const u8 r2 = bpf2a64[BPF_REG_2];
+ const u8 r3 = bpf2a64[BPF_REG_3];
+
+ const u8 tmp = bpf2a64[TMP_REG_1];
+ const u8 prg = bpf2a64[TMP_REG_2];
+ const u8 tcc = bpf2a64[TCALL_CNT];
+ const int idx0 = ctx->idx;
+#define cur_offset (ctx->idx - idx0)
+#define jmp_offset (out_offset - (cur_offset))
+ size_t off;
+
+ /* if (index >= array->map.max_entries)
+ * goto out;
+ */
+ off = offsetof(struct bpf_array, map.max_entries);
+ emit_a64_mov_i64(tmp, off, ctx);
+ emit(A64_LDR32(tmp, r2, tmp), ctx);
+ emit(A64_MOV(0, r3, r3), ctx);
+ emit(A64_CMP(0, r3, tmp), ctx);
+ emit(A64_B_(A64_COND_CS, jmp_offset), ctx);
+
+ /* if (tail_call_cnt > MAX_TAIL_CALL_CNT)
+ * goto out;
+ * tail_call_cnt++;
+ */
+ emit_a64_mov_i64(tmp, MAX_TAIL_CALL_CNT, ctx);
+ emit(A64_CMP(1, tcc, tmp), ctx);
+ emit(A64_B_(A64_COND_HI, jmp_offset), ctx);
+ emit(A64_ADD_I(1, tcc, tcc, 1), ctx);
+
+ /* prog = array->ptrs[index];
+ * if (prog == NULL)
+ * goto out;
+ */
+ off = offsetof(struct bpf_array, ptrs);
+ emit_a64_mov_i64(tmp, off, ctx);
+ emit(A64_ADD(1, tmp, r2, tmp), ctx);
+ emit(A64_LSL(1, prg, r3, 3), ctx);
+ emit(A64_LDR64(prg, tmp, prg), ctx);
+ emit(A64_CBZ(1, prg, jmp_offset), ctx);
+
+ /* goto *(prog->bpf_func + prologue_offset); */
+ off = offsetof(struct bpf_prog, bpf_func);
+ emit_a64_mov_i64(tmp, off, ctx);
+ emit(A64_LDR64(tmp, prg, tmp), ctx);
+ emit(A64_ADD_I(1, tmp, tmp, sizeof(u32) * PROLOGUE_OFFSET), ctx);
+ emit(A64_ADD_I(1, A64_SP, A64_SP, ctx->stack_size), ctx);
+ emit(A64_BR(tmp), ctx);
+
+ /* out: */
+ if (out_offset == -1)
+ out_offset = cur_offset;
+ if (cur_offset != out_offset) {
+ pr_err_once("tail_call out_offset = %d, expected %d!\n",
+ cur_offset, out_offset);
+ return -1;
+ }
+ return 0;
+#undef cur_offset
+#undef jmp_offset
+}
+
+static void build_epilogue(struct jit_ctx *ctx)
+{
+ const u8 r0 = bpf2a64[BPF_REG_0];
+ const u8 r6 = bpf2a64[BPF_REG_6];
+ const u8 r7 = bpf2a64[BPF_REG_7];
+ const u8 r8 = bpf2a64[BPF_REG_8];
+ const u8 r9 = bpf2a64[BPF_REG_9];
+ const u8 fp = bpf2a64[BPF_REG_FP];
+
+ /* We're done with BPF stack */
+ emit(A64_ADD_I(1, A64_SP, A64_SP, ctx->stack_size), ctx);
+
+ /* Restore fs (x25) and x26 */
+ emit(A64_POP(fp, A64_R(26), A64_SP), ctx);
+
+ /* Restore callee-saved register */
+ emit(A64_POP(r8, r9, A64_SP), ctx);
+ emit(A64_POP(r6, r7, A64_SP), ctx);
+
+ /* Restore FP/LR registers */
+ emit(A64_POP(A64_FP, A64_LR, A64_SP), ctx);
+
+ /* Set return value */
+ emit(A64_MOV(1, A64_R(0), r0), ctx);
+
+ emit(A64_RET(A64_LR), ctx);
+}
+
+#define BPF_FIXUP_OFFSET_MASK GENMASK(26, 0)
+#define BPF_FIXUP_REG_MASK GENMASK(31, 27)
+
+int arm64_bpf_fixup_exception(const struct exception_table_entry *ex,
+ struct pt_regs *regs)
+{
+ off_t offset = FIELD_GET(BPF_FIXUP_OFFSET_MASK, ex->fixup);
+ int dst_reg = FIELD_GET(BPF_FIXUP_REG_MASK, ex->fixup);
+
+ regs->regs[dst_reg] = 0;
+ regs->pc = (unsigned long)&ex->fixup - offset;
+ return 1;
+}
+
+/* For accesses to BTF pointers, add an entry to the exception table */
+static int add_exception_handler(const struct bpf_insn *insn,
+ struct jit_ctx *ctx,
+ int dst_reg)
+{
+ off_t offset;
+ unsigned long pc;
+ struct exception_table_entry *ex;
+
+ if (!ctx->image)
+ /* First pass */
+ return 0;
+
+ if (BPF_MODE(insn->code) != BPF_PROBE_MEM)
+ return 0;
+
+ if (!ctx->prog->aux->extable ||
+ WARN_ON_ONCE(ctx->exentry_idx >= ctx->prog->aux->num_exentries))
+ return -EINVAL;
+
+ ex = &ctx->prog->aux->extable[ctx->exentry_idx];
+ pc = (unsigned long)&ctx->image[ctx->idx - 1];
+
+ offset = pc - (long)&ex->insn;
+ if (WARN_ON_ONCE(offset >= 0 || offset < INT_MIN))
+ return -ERANGE;
+ ex->insn = offset;
+
+ /*
+ * Since the extable follows the program, the fixup offset is always
+ * negative and limited to BPF_JIT_REGION_SIZE. Store a positive value
+ * to keep things simple, and put the destination register in the upper
+ * bits. We don't need to worry about buildtime or runtime sort
+ * modifying the upper bits because the table is already sorted, and
+ * isn't part of the main exception table.
+ */
+ offset = (long)&ex->fixup - (pc + AARCH64_INSN_SIZE);
+ if (!FIELD_FIT(BPF_FIXUP_OFFSET_MASK, offset))
+ return -ERANGE;
+
+ ex->fixup = FIELD_PREP(BPF_FIXUP_OFFSET_MASK, offset) |
+ FIELD_PREP(BPF_FIXUP_REG_MASK, dst_reg);
+
+ ctx->exentry_idx++;
+ return 0;
+}
+
+/* JITs an eBPF instruction.
+ * Returns:
+ * 0 - successfully JITed an 8-byte eBPF instruction.
+ * >0 - successfully JITed a 16-byte eBPF instruction.
+ * <0 - failed to JIT.
+ */
+static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx,
+ bool extra_pass)
+{
+ const u8 code = insn->code;
+ const u8 dst = bpf2a64[insn->dst_reg];
+ const u8 src = bpf2a64[insn->src_reg];
+ const u8 tmp = bpf2a64[TMP_REG_1];
+ const u8 tmp2 = bpf2a64[TMP_REG_2];
+ const u8 tmp3 = bpf2a64[TMP_REG_3];
+ const s16 off = insn->off;
+ const s32 imm = insn->imm;
+ const int i = insn - ctx->prog->insnsi;
+ const bool is64 = BPF_CLASS(code) == BPF_ALU64 ||
+ BPF_CLASS(code) == BPF_JMP;
+ const bool isdw = BPF_SIZE(code) == BPF_DW;
+ u8 jmp_cond, reg;
+ s32 jmp_offset;
+ u32 a64_insn;
+ int ret;
+
+#define check_imm(bits, imm) do { \
+ if ((((imm) > 0) && ((imm) >> (bits))) || \
+ (((imm) < 0) && (~(imm) >> (bits)))) { \
+ pr_info("[%2d] imm=%d(0x%x) out of range\n", \
+ i, imm, imm); \
+ return -EINVAL; \
+ } \
+} while (0)
+#define check_imm19(imm) check_imm(19, imm)
+#define check_imm26(imm) check_imm(26, imm)
+
+ switch (code) {
+ /* dst = src */
+ case BPF_ALU | BPF_MOV | BPF_X:
+ case BPF_ALU64 | BPF_MOV | BPF_X:
+ emit(A64_MOV(is64, dst, src), ctx);
+ break;
+ /* dst = dst OP src */
+ case BPF_ALU | BPF_ADD | BPF_X:
+ case BPF_ALU64 | BPF_ADD | BPF_X:
+ emit(A64_ADD(is64, dst, dst, src), ctx);
+ break;
+ case BPF_ALU | BPF_SUB | BPF_X:
+ case BPF_ALU64 | BPF_SUB | BPF_X:
+ emit(A64_SUB(is64, dst, dst, src), ctx);
+ break;
+ case BPF_ALU | BPF_AND | BPF_X:
+ case BPF_ALU64 | BPF_AND | BPF_X:
+ emit(A64_AND(is64, dst, dst, src), ctx);
+ break;
+ case BPF_ALU | BPF_OR | BPF_X:
+ case BPF_ALU64 | BPF_OR | BPF_X:
+ emit(A64_ORR(is64, dst, dst, src), ctx);
+ break;
+ case BPF_ALU | BPF_XOR | BPF_X:
+ case BPF_ALU64 | BPF_XOR | BPF_X:
+ emit(A64_EOR(is64, dst, dst, src), ctx);
+ break;
+ case BPF_ALU | BPF_MUL | BPF_X:
+ case BPF_ALU64 | BPF_MUL | BPF_X:
+ emit(A64_MUL(is64, dst, dst, src), ctx);
+ break;
+ case BPF_ALU | BPF_DIV | BPF_X:
+ case BPF_ALU64 | BPF_DIV | BPF_X:
+ case BPF_ALU | BPF_MOD | BPF_X:
+ case BPF_ALU64 | BPF_MOD | BPF_X:
+ switch (BPF_OP(code)) {
+ case BPF_DIV:
+ emit(A64_UDIV(is64, dst, dst, src), ctx);
+ break;
+ case BPF_MOD:
+ emit(A64_UDIV(is64, tmp, dst, src), ctx);
+ emit(A64_MSUB(is64, dst, dst, tmp, src), ctx);
+ break;
+ }
+ break;
+ case BPF_ALU | BPF_LSH | BPF_X:
+ case BPF_ALU64 | BPF_LSH | BPF_X:
+ emit(A64_LSLV(is64, dst, dst, src), ctx);
+ break;
+ case BPF_ALU | BPF_RSH | BPF_X:
+ case BPF_ALU64 | BPF_RSH | BPF_X:
+ emit(A64_LSRV(is64, dst, dst, src), ctx);
+ break;
+ case BPF_ALU | BPF_ARSH | BPF_X:
+ case BPF_ALU64 | BPF_ARSH | BPF_X:
+ emit(A64_ASRV(is64, dst, dst, src), ctx);
+ break;
+ /* dst = -dst */
+ case BPF_ALU | BPF_NEG:
+ case BPF_ALU64 | BPF_NEG:
+ emit(A64_NEG(is64, dst, dst), ctx);
+ break;
+ /* dst = BSWAP##imm(dst) */
+ case BPF_ALU | BPF_END | BPF_FROM_LE:
+ case BPF_ALU | BPF_END | BPF_FROM_BE:
+#ifdef CONFIG_CPU_BIG_ENDIAN
+ if (BPF_SRC(code) == BPF_FROM_BE)
+ goto emit_bswap_uxt;
+#else /* !CONFIG_CPU_BIG_ENDIAN */
+ if (BPF_SRC(code) == BPF_FROM_LE)
+ goto emit_bswap_uxt;
+#endif
+ switch (imm) {
+ case 16:
+ emit(A64_REV16(is64, dst, dst), ctx);
+ /* zero-extend 16 bits into 64 bits */
+ emit(A64_UXTH(is64, dst, dst), ctx);
+ break;
+ case 32:
+ emit(A64_REV32(is64, dst, dst), ctx);
+ /* upper 32 bits already cleared */
+ break;
+ case 64:
+ emit(A64_REV64(dst, dst), ctx);
+ break;
+ }
+ break;
+emit_bswap_uxt:
+ switch (imm) {
+ case 16:
+ /* zero-extend 16 bits into 64 bits */
+ emit(A64_UXTH(is64, dst, dst), ctx);
+ break;
+ case 32:
+ /* zero-extend 32 bits into 64 bits */
+ emit(A64_UXTW(is64, dst, dst), ctx);
+ break;
+ case 64:
+ /* nop */
+ break;
+ }
+ break;
+ /* dst = imm */
+ case BPF_ALU | BPF_MOV | BPF_K:
+ case BPF_ALU64 | BPF_MOV | BPF_K:
+ emit_a64_mov_i(is64, dst, imm, ctx);
+ break;
+ /* dst = dst OP imm */
+ case BPF_ALU | BPF_ADD | BPF_K:
+ case BPF_ALU64 | BPF_ADD | BPF_K:
+ if (is_addsub_imm(imm)) {
+ emit(A64_ADD_I(is64, dst, dst, imm), ctx);
+ } else if (is_addsub_imm(-imm)) {
+ emit(A64_SUB_I(is64, dst, dst, -imm), ctx);
+ } else {
+ emit_a64_mov_i(is64, tmp, imm, ctx);
+ emit(A64_ADD(is64, dst, dst, tmp), ctx);
+ }
+ break;
+ case BPF_ALU | BPF_SUB | BPF_K:
+ case BPF_ALU64 | BPF_SUB | BPF_K:
+ if (is_addsub_imm(imm)) {
+ emit(A64_SUB_I(is64, dst, dst, imm), ctx);
+ } else if (is_addsub_imm(-imm)) {
+ emit(A64_ADD_I(is64, dst, dst, -imm), ctx);
+ } else {
+ emit_a64_mov_i(is64, tmp, imm, ctx);
+ emit(A64_SUB(is64, dst, dst, tmp), ctx);
+ }
+ break;
+ case BPF_ALU | BPF_AND | BPF_K:
+ case BPF_ALU64 | BPF_AND | BPF_K:
+ a64_insn = A64_AND_I(is64, dst, dst, imm);
+ if (a64_insn != AARCH64_BREAK_FAULT) {
+ emit(a64_insn, ctx);
+ } else {
+ emit_a64_mov_i(is64, tmp, imm, ctx);
+ emit(A64_AND(is64, dst, dst, tmp), ctx);
+ }
+ break;
+ case BPF_ALU | BPF_OR | BPF_K:
+ case BPF_ALU64 | BPF_OR | BPF_K:
+ a64_insn = A64_ORR_I(is64, dst, dst, imm);
+ if (a64_insn != AARCH64_BREAK_FAULT) {
+ emit(a64_insn, ctx);
+ } else {
+ emit_a64_mov_i(is64, tmp, imm, ctx);
+ emit(A64_ORR(is64, dst, dst, tmp), ctx);
+ }
+ break;
+ case BPF_ALU | BPF_XOR | BPF_K:
+ case BPF_ALU64 | BPF_XOR | BPF_K:
+ a64_insn = A64_EOR_I(is64, dst, dst, imm);
+ if (a64_insn != AARCH64_BREAK_FAULT) {
+ emit(a64_insn, ctx);
+ } else {
+ emit_a64_mov_i(is64, tmp, imm, ctx);
+ emit(A64_EOR(is64, dst, dst, tmp), ctx);
+ }
+ break;
+ case BPF_ALU | BPF_MUL | BPF_K:
+ case BPF_ALU64 | BPF_MUL | BPF_K:
+ emit_a64_mov_i(is64, tmp, imm, ctx);
+ emit(A64_MUL(is64, dst, dst, tmp), ctx);
+ break;
+ case BPF_ALU | BPF_DIV | BPF_K:
+ case BPF_ALU64 | BPF_DIV | BPF_K:
+ emit_a64_mov_i(is64, tmp, imm, ctx);
+ emit(A64_UDIV(is64, dst, dst, tmp), ctx);
+ break;
+ case BPF_ALU | BPF_MOD | BPF_K:
+ case BPF_ALU64 | BPF_MOD | BPF_K:
+ emit_a64_mov_i(is64, tmp2, imm, ctx);
+ emit(A64_UDIV(is64, tmp, dst, tmp2), ctx);
+ emit(A64_MSUB(is64, dst, dst, tmp, tmp2), ctx);
+ break;
+ case BPF_ALU | BPF_LSH | BPF_K:
+ case BPF_ALU64 | BPF_LSH | BPF_K:
+ emit(A64_LSL(is64, dst, dst, imm), ctx);
+ break;
+ case BPF_ALU | BPF_RSH | BPF_K:
+ case BPF_ALU64 | BPF_RSH | BPF_K:
+ emit(A64_LSR(is64, dst, dst, imm), ctx);
+ break;
+ case BPF_ALU | BPF_ARSH | BPF_K:
+ case BPF_ALU64 | BPF_ARSH | BPF_K:
+ emit(A64_ASR(is64, dst, dst, imm), ctx);
+ break;
+
+ /* JUMP off */
+ case BPF_JMP | BPF_JA:
+ jmp_offset = bpf2a64_offset(i, off, ctx);
+ check_imm26(jmp_offset);
+ emit(A64_B(jmp_offset), ctx);
+ break;
+ /* IF (dst COND src) JUMP off */
+ case BPF_JMP | BPF_JEQ | BPF_X:
+ case BPF_JMP | BPF_JGT | BPF_X:
+ case BPF_JMP | BPF_JLT | BPF_X:
+ case BPF_JMP | BPF_JGE | BPF_X:
+ case BPF_JMP | BPF_JLE | BPF_X:
+ case BPF_JMP | BPF_JNE | BPF_X:
+ case BPF_JMP | BPF_JSGT | BPF_X:
+ case BPF_JMP | BPF_JSLT | BPF_X:
+ case BPF_JMP | BPF_JSGE | BPF_X:
+ case BPF_JMP | BPF_JSLE | BPF_X:
+ case BPF_JMP32 | BPF_JEQ | BPF_X:
+ case BPF_JMP32 | BPF_JGT | BPF_X:
+ case BPF_JMP32 | BPF_JLT | BPF_X:
+ case BPF_JMP32 | BPF_JGE | BPF_X:
+ case BPF_JMP32 | BPF_JLE | BPF_X:
+ case BPF_JMP32 | BPF_JNE | BPF_X:
+ case BPF_JMP32 | BPF_JSGT | BPF_X:
+ case BPF_JMP32 | BPF_JSLT | BPF_X:
+ case BPF_JMP32 | BPF_JSGE | BPF_X:
+ case BPF_JMP32 | BPF_JSLE | BPF_X:
+ emit(A64_CMP(is64, dst, src), ctx);
+emit_cond_jmp:
+ jmp_offset = bpf2a64_offset(i, off, ctx);
+ check_imm19(jmp_offset);
+ switch (BPF_OP(code)) {
+ case BPF_JEQ:
+ jmp_cond = A64_COND_EQ;
+ break;
+ case BPF_JGT:
+ jmp_cond = A64_COND_HI;
+ break;
+ case BPF_JLT:
+ jmp_cond = A64_COND_CC;
+ break;
+ case BPF_JGE:
+ jmp_cond = A64_COND_CS;
+ break;
+ case BPF_JLE:
+ jmp_cond = A64_COND_LS;
+ break;
+ case BPF_JSET:
+ case BPF_JNE:
+ jmp_cond = A64_COND_NE;
+ break;
+ case BPF_JSGT:
+ jmp_cond = A64_COND_GT;
+ break;
+ case BPF_JSLT:
+ jmp_cond = A64_COND_LT;
+ break;
+ case BPF_JSGE:
+ jmp_cond = A64_COND_GE;
+ break;
+ case BPF_JSLE:
+ jmp_cond = A64_COND_LE;
+ break;
+ default:
+ return -EFAULT;
+ }
+ emit(A64_B_(jmp_cond, jmp_offset), ctx);
+ break;
+ case BPF_JMP | BPF_JSET | BPF_X:
+ case BPF_JMP32 | BPF_JSET | BPF_X:
+ emit(A64_TST(is64, dst, src), ctx);
+ goto emit_cond_jmp;
+ /* IF (dst COND imm) JUMP off */
+ case BPF_JMP | BPF_JEQ | BPF_K:
+ case BPF_JMP | BPF_JGT | BPF_K:
+ case BPF_JMP | BPF_JLT | BPF_K:
+ case BPF_JMP | BPF_JGE | BPF_K:
+ case BPF_JMP | BPF_JLE | BPF_K:
+ case BPF_JMP | BPF_JNE | BPF_K:
+ case BPF_JMP | BPF_JSGT | BPF_K:
+ case BPF_JMP | BPF_JSLT | BPF_K:
+ case BPF_JMP | BPF_JSGE | BPF_K:
+ case BPF_JMP | BPF_JSLE | BPF_K:
+ case BPF_JMP32 | BPF_JEQ | BPF_K:
+ case BPF_JMP32 | BPF_JGT | BPF_K:
+ case BPF_JMP32 | BPF_JLT | BPF_K:
+ case BPF_JMP32 | BPF_JGE | BPF_K:
+ case BPF_JMP32 | BPF_JLE | BPF_K:
+ case BPF_JMP32 | BPF_JNE | BPF_K:
+ case BPF_JMP32 | BPF_JSGT | BPF_K:
+ case BPF_JMP32 | BPF_JSLT | BPF_K:
+ case BPF_JMP32 | BPF_JSGE | BPF_K:
+ case BPF_JMP32 | BPF_JSLE | BPF_K:
+ if (is_addsub_imm(imm)) {
+ emit(A64_CMP_I(is64, dst, imm), ctx);
+ } else if (is_addsub_imm(-imm)) {
+ emit(A64_CMN_I(is64, dst, -imm), ctx);
+ } else {
+ emit_a64_mov_i(is64, tmp, imm, ctx);
+ emit(A64_CMP(is64, dst, tmp), ctx);
+ }
+ goto emit_cond_jmp;
+ case BPF_JMP | BPF_JSET | BPF_K:
+ case BPF_JMP32 | BPF_JSET | BPF_K:
+ a64_insn = A64_TST_I(is64, dst, imm);
+ if (a64_insn != AARCH64_BREAK_FAULT) {
+ emit(a64_insn, ctx);
+ } else {
+ emit_a64_mov_i(is64, tmp, imm, ctx);
+ emit(A64_TST(is64, dst, tmp), ctx);
+ }
+ goto emit_cond_jmp;
+ /* function call */
+ case BPF_JMP | BPF_CALL:
+ {
+ const u8 r0 = bpf2a64[BPF_REG_0];
+ bool func_addr_fixed;
+ u64 func_addr;
+
+ ret = bpf_jit_get_func_addr(ctx->prog, insn, extra_pass,
+ &func_addr, &func_addr_fixed);
+ if (ret < 0)
+ return ret;
+ emit_addr_mov_i64(tmp, func_addr, ctx);
+ emit(A64_BLR(tmp), ctx);
+ emit(A64_MOV(1, r0, A64_R(0)), ctx);
+ break;
+ }
+ /* tail call */
+ case BPF_JMP | BPF_TAIL_CALL:
+ if (emit_bpf_tail_call(ctx))
+ return -EFAULT;
+ break;
+ /* function return */
+ case BPF_JMP | BPF_EXIT:
+ /* Optimization: when last instruction is EXIT,
+ simply fallthrough to epilogue. */
+ if (i == ctx->prog->len - 1)
+ break;
+ jmp_offset = epilogue_offset(ctx);
+ check_imm26(jmp_offset);
+ emit(A64_B(jmp_offset), ctx);
+ break;
+
+ /* dst = imm64 */
+ case BPF_LD | BPF_IMM | BPF_DW:
+ {
+ const struct bpf_insn insn1 = insn[1];
+ u64 imm64;
+
+ imm64 = (u64)insn1.imm << 32 | (u32)imm;
+ emit_a64_mov_i64(dst, imm64, ctx);
+
+ return 1;
+ }
+
+ /* LDX: 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:
+ case BPF_LDX | BPF_PROBE_MEM | BPF_DW:
+ case BPF_LDX | BPF_PROBE_MEM | BPF_W:
+ case BPF_LDX | BPF_PROBE_MEM | BPF_H:
+ case BPF_LDX | BPF_PROBE_MEM | BPF_B:
+ emit_a64_mov_i(1, tmp, off, ctx);
+ switch (BPF_SIZE(code)) {
+ case BPF_W:
+ emit(A64_LDR32(dst, src, tmp), ctx);
+ break;
+ case BPF_H:
+ emit(A64_LDRH(dst, src, tmp), ctx);
+ break;
+ case BPF_B:
+ emit(A64_LDRB(dst, src, tmp), ctx);
+ break;
+ case BPF_DW:
+ emit(A64_LDR64(dst, src, tmp), ctx);
+ break;
+ }
+
+ ret = add_exception_handler(insn, ctx, dst);
+ if (ret)
+ return ret;
+ break;
+
+ /* speculation barrier */
+ case BPF_ST | BPF_NOSPEC:
+ /*
+ * Nothing required here.
+ *
+ * In case of arm64, we rely on the firmware mitigation of
+ * Speculative Store Bypass as controlled via the ssbd kernel
+ * parameter. Whenever the mitigation is enabled, it works
+ * for all of the kernel code with no need to provide any
+ * additional instructions.
+ */
+ break;
+
+ /* ST: *(size *)(dst + off) = imm */
+ 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:
+ /* Load imm to a register then store it */
+ emit_a64_mov_i(1, tmp2, off, ctx);
+ emit_a64_mov_i(1, tmp, imm, ctx);
+ switch (BPF_SIZE(code)) {
+ case BPF_W:
+ emit(A64_STR32(tmp, dst, tmp2), ctx);
+ break;
+ case BPF_H:
+ emit(A64_STRH(tmp, dst, tmp2), ctx);
+ break;
+ case BPF_B:
+ emit(A64_STRB(tmp, dst, tmp2), ctx);
+ break;
+ case BPF_DW:
+ emit(A64_STR64(tmp, dst, tmp2), ctx);
+ break;
+ }
+ break;
+
+ /* STX: *(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:
+ emit_a64_mov_i(1, tmp, off, ctx);
+ switch (BPF_SIZE(code)) {
+ case BPF_W:
+ emit(A64_STR32(src, dst, tmp), ctx);
+ break;
+ case BPF_H:
+ emit(A64_STRH(src, dst, tmp), ctx);
+ break;
+ case BPF_B:
+ emit(A64_STRB(src, dst, tmp), ctx);
+ break;
+ case BPF_DW:
+ emit(A64_STR64(src, dst, tmp), ctx);
+ break;
+ }
+ break;
+
+ /* STX XADD: lock *(u32 *)(dst + off) += src */
+ case BPF_STX | BPF_XADD | BPF_W:
+ /* STX XADD: lock *(u64 *)(dst + off) += src */
+ case BPF_STX | BPF_XADD | BPF_DW:
+ if (!off) {
+ reg = dst;
+ } else {
+ emit_a64_mov_i(1, tmp, off, ctx);
+ emit(A64_ADD(1, tmp, tmp, dst), ctx);
+ reg = tmp;
+ }
+ if (cpus_have_cap(ARM64_HAS_LSE_ATOMICS)) {
+ emit(A64_STADD(isdw, reg, src), ctx);
+ } else {
+ emit(A64_LDXR(isdw, tmp2, reg), ctx);
+ emit(A64_ADD(isdw, tmp2, tmp2, src), ctx);
+ emit(A64_STXR(isdw, tmp2, reg, tmp3), ctx);
+ jmp_offset = -3;
+ check_imm19(jmp_offset);
+ emit(A64_CBNZ(0, tmp3, jmp_offset), ctx);
+ }
+ break;
+
+ default:
+ pr_err_once("unknown opcode %02x\n", code);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int build_body(struct jit_ctx *ctx, bool extra_pass)
+{
+ const struct bpf_prog *prog = ctx->prog;
+ int i;
+
+ /*
+ * - offset[0] offset of the end of prologue,
+ * start of the 1st instruction.
+ * - offset[1] - offset of the end of 1st instruction,
+ * start of the 2nd instruction
+ * [....]
+ * - offset[3] - offset of the end of 3rd instruction,
+ * start of 4th instruction
+ */
+ for (i = 0; i < prog->len; i++) {
+ const struct bpf_insn *insn = &prog->insnsi[i];
+ int ret;
+
+ if (ctx->image == NULL)
+ ctx->offset[i] = ctx->idx;
+ ret = build_insn(insn, ctx, extra_pass);
+ if (ret > 0) {
+ i++;
+ if (ctx->image == NULL)
+ ctx->offset[i] = ctx->idx;
+ continue;
+ }
+ if (ret)
+ return ret;
+ }
+ /*
+ * offset is allocated with prog->len + 1 so fill in
+ * the last element with the offset after the last
+ * instruction (end of program)
+ */
+ if (ctx->image == NULL)
+ ctx->offset[i] = ctx->idx;
+
+ return 0;
+}
+
+static int validate_code(struct jit_ctx *ctx)
+{
+ int i;
+
+ for (i = 0; i < ctx->idx; i++) {
+ u32 a64_insn = le32_to_cpu(ctx->image[i]);
+
+ if (a64_insn == AARCH64_BREAK_FAULT)
+ return -1;
+ }
+
+ if (WARN_ON_ONCE(ctx->exentry_idx != ctx->prog->aux->num_exentries))
+ return -1;
+
+ return 0;
+}
+
+static inline void bpf_flush_icache(void *start, void *end)
+{
+ flush_icache_range((unsigned long)start, (unsigned long)end);
+}
+
+struct arm64_jit_data {
+ struct bpf_binary_header *header;
+ u8 *image;
+ struct jit_ctx ctx;
+};
+
+struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
+{
+ int image_size, prog_size, extable_size;
+ struct bpf_prog *tmp, *orig_prog = prog;
+ struct bpf_binary_header *header;
+ struct arm64_jit_data *jit_data;
+ bool was_classic = bpf_prog_was_classic(prog);
+ bool tmp_blinded = false;
+ bool extra_pass = false;
+ struct jit_ctx ctx;
+ u8 *image_ptr;
+
+ if (!prog->jit_requested)
+ return orig_prog;
+
+ tmp = bpf_jit_blind_constants(prog);
+ /* If blinding was requested and we failed during blinding,
+ * we must fall back to the interpreter.
+ */
+ if (IS_ERR(tmp))
+ return orig_prog;
+ if (tmp != prog) {
+ tmp_blinded = true;
+ prog = tmp;
+ }
+
+ jit_data = prog->aux->jit_data;
+ if (!jit_data) {
+ jit_data = kzalloc(sizeof(*jit_data), GFP_KERNEL);
+ if (!jit_data) {
+ prog = orig_prog;
+ goto out;
+ }
+ prog->aux->jit_data = jit_data;
+ }
+ if (jit_data->ctx.offset) {
+ ctx = jit_data->ctx;
+ image_ptr = jit_data->image;
+ header = jit_data->header;
+ extra_pass = true;
+ prog_size = sizeof(u32) * ctx.idx;
+ goto skip_init_ctx;
+ }
+ memset(&ctx, 0, sizeof(ctx));
+ ctx.prog = prog;
+
+ ctx.offset = kcalloc(prog->len + 1, sizeof(int), GFP_KERNEL);
+ if (ctx.offset == NULL) {
+ prog = orig_prog;
+ goto out_off;
+ }
+
+ /*
+ * 1. Initial fake pass to compute ctx->idx and ctx->offset.
+ *
+ * BPF line info needs ctx->offset[i] to be the offset of
+ * instruction[i] in jited image, so build prologue first.
+ */
+ if (build_prologue(&ctx, was_classic)) {
+ prog = orig_prog;
+ goto out_off;
+ }
+
+ if (build_body(&ctx, extra_pass)) {
+ prog = orig_prog;
+ goto out_off;
+ }
+
+ ctx.epilogue_offset = ctx.idx;
+ build_epilogue(&ctx);
+
+ extable_size = prog->aux->num_exentries *
+ sizeof(struct exception_table_entry);
+
+ /* Now we know the actual image size. */
+ prog_size = sizeof(u32) * ctx.idx;
+ image_size = prog_size + extable_size;
+ header = bpf_jit_binary_alloc(image_size, &image_ptr,
+ sizeof(u32), jit_fill_hole);
+ if (header == NULL) {
+ prog = orig_prog;
+ goto out_off;
+ }
+
+ /* 2. Now, the actual pass. */
+
+ ctx.image = (__le32 *)image_ptr;
+ if (extable_size)
+ prog->aux->extable = (void *)image_ptr + prog_size;
+skip_init_ctx:
+ ctx.idx = 0;
+ ctx.exentry_idx = 0;
+
+ build_prologue(&ctx, was_classic);
+
+ if (build_body(&ctx, extra_pass)) {
+ bpf_jit_binary_free(header);
+ prog = orig_prog;
+ goto out_off;
+ }
+
+ build_epilogue(&ctx);
+
+ /* 3. Extra pass to validate JITed code. */
+ if (validate_code(&ctx)) {
+ bpf_jit_binary_free(header);
+ prog = orig_prog;
+ goto out_off;
+ }
+
+ /* And we're done. */
+ if (bpf_jit_enable > 1)
+ bpf_jit_dump(prog->len, prog_size, 2, ctx.image);
+
+ bpf_flush_icache(header, ctx.image + ctx.idx);
+
+ if (!prog->is_func || extra_pass) {
+ if (extra_pass && ctx.idx != jit_data->ctx.idx) {
+ pr_err_once("multi-func JIT bug %d != %d\n",
+ ctx.idx, jit_data->ctx.idx);
+ bpf_jit_binary_free(header);
+ prog->bpf_func = NULL;
+ prog->jited = 0;
+ prog->jited_len = 0;
+ goto out_off;
+ }
+ bpf_jit_binary_lock_ro(header);
+ } else {
+ jit_data->ctx = ctx;
+ jit_data->image = image_ptr;
+ jit_data->header = header;
+ }
+ prog->bpf_func = (void *)ctx.image;
+ prog->jited = 1;
+ prog->jited_len = prog_size;
+
+ if (!prog->is_func || extra_pass) {
+ int i;
+
+ /* offset[prog->len] is the size of program */
+ for (i = 0; i <= prog->len; i++)
+ ctx.offset[i] *= AARCH64_INSN_SIZE;
+ bpf_prog_fill_jited_linfo(prog, ctx.offset + 1);
+out_off:
+ kfree(ctx.offset);
+ kfree(jit_data);
+ prog->aux->jit_data = NULL;
+ }
+out:
+ if (tmp_blinded)
+ bpf_jit_prog_release_other(prog, prog == orig_prog ?
+ tmp : orig_prog);
+ return prog;
+}
+
+u64 bpf_jit_alloc_exec_limit(void)
+{
+ return BPF_JIT_REGION_SIZE;
+}
+
+void *bpf_jit_alloc_exec(unsigned long size)
+{
+ return __vmalloc_node_range(size, PAGE_SIZE, BPF_JIT_REGION_START,
+ BPF_JIT_REGION_END, GFP_KERNEL,
+ PAGE_KERNEL, 0, NUMA_NO_NODE,
+ __builtin_return_address(0));
+}
+
+void bpf_jit_free_exec(void *addr)
+{
+ return vfree(addr);
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-27 08:09:14 +0000