diff options
Diffstat (limited to 'arch/csky/abiv1/alignment.c')
| -rw-r--r-- | arch/csky/abiv1/alignment.c | 354 |
1 files changed, 354 insertions, 0 deletions
diff --git a/arch/csky/abiv1/alignment.c b/arch/csky/abiv1/alignment.c new file mode 100644 index 000000000..2df115d0e --- /dev/null +++ b/arch/csky/abiv1/alignment.c @@ -0,0 +1,354 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd. + +#include <linux/kernel.h> +#include <linux/uaccess.h> +#include <linux/ptrace.h> + +static int align_kern_enable = 1; +static int align_usr_enable = 1; +static int align_kern_count = 0; +static int align_usr_count = 0; + +static inline uint32_t get_ptreg(struct pt_regs *regs, uint32_t rx) +{ + return rx == 15 ? regs->lr : *((uint32_t *)&(regs->a0) - 2 + rx); +} + +static inline void put_ptreg(struct pt_regs *regs, uint32_t rx, uint32_t val) +{ + if (rx == 15) + regs->lr = val; + else + *((uint32_t *)&(regs->a0) - 2 + rx) = val; +} + +/* + * Get byte-value from addr and set it to *valp. + * + * Success: return 0 + * Failure: return 1 + */ +static int ldb_asm(uint32_t addr, uint32_t *valp) +{ + uint32_t val; + int err; + + asm volatile ( + "movi %0, 0\n" + "1:\n" + "ldb %1, (%2)\n" + "br 3f\n" + "2:\n" + "movi %0, 1\n" + "br 3f\n" + ".section __ex_table,\"a\"\n" + ".align 2\n" + ".long 1b, 2b\n" + ".previous\n" + "3:\n" + : "=&r"(err), "=r"(val) + : "r" (addr) + ); + + *valp = val; + + return err; +} + +/* + * Put byte-value to addr. + * + * Success: return 0 + * Failure: return 1 + */ +static int stb_asm(uint32_t addr, uint32_t val) +{ + int err; + + asm volatile ( + "movi %0, 0\n" + "1:\n" + "stb %1, (%2)\n" + "br 3f\n" + "2:\n" + "movi %0, 1\n" + "br 3f\n" + ".section __ex_table,\"a\"\n" + ".align 2\n" + ".long 1b, 2b\n" + ".previous\n" + "3:\n" + : "=&r"(err) + : "r"(val), "r" (addr) + ); + + return err; +} + +/* + * Get half-word from [rx + imm] + * + * Success: return 0 + * Failure: return 1 + */ +static int ldh_c(struct pt_regs *regs, uint32_t rz, uint32_t addr) +{ + uint32_t byte0, byte1; + + if (ldb_asm(addr, &byte0)) + return 1; + addr += 1; + if (ldb_asm(addr, &byte1)) + return 1; + + byte0 |= byte1 << 8; + put_ptreg(regs, rz, byte0); + + return 0; +} + +/* + * Store half-word to [rx + imm] + * + * Success: return 0 + * Failure: return 1 + */ +static int sth_c(struct pt_regs *regs, uint32_t rz, uint32_t addr) +{ + uint32_t byte0, byte1; + + byte0 = byte1 = get_ptreg(regs, rz); + + byte0 &= 0xff; + + if (stb_asm(addr, byte0)) + return 1; + + addr += 1; + byte1 = (byte1 >> 8) & 0xff; + if (stb_asm(addr, byte1)) + return 1; + + return 0; +} + +/* + * Get word from [rx + imm] + * + * Success: return 0 + * Failure: return 1 + */ +static int ldw_c(struct pt_regs *regs, uint32_t rz, uint32_t addr) +{ + uint32_t byte0, byte1, byte2, byte3; + + if (ldb_asm(addr, &byte0)) + return 1; + + addr += 1; + if (ldb_asm(addr, &byte1)) + return 1; + + addr += 1; + if (ldb_asm(addr, &byte2)) + return 1; + + addr += 1; + if (ldb_asm(addr, &byte3)) + return 1; + + byte0 |= byte1 << 8; + byte0 |= byte2 << 16; + byte0 |= byte3 << 24; + + put_ptreg(regs, rz, byte0); + + return 0; +} + +/* + * Store word to [rx + imm] + * + * Success: return 0 + * Failure: return 1 + */ +static int stw_c(struct pt_regs *regs, uint32_t rz, uint32_t addr) +{ + uint32_t byte0, byte1, byte2, byte3; + + byte0 = byte1 = byte2 = byte3 = get_ptreg(regs, rz); + + byte0 &= 0xff; + + if (stb_asm(addr, byte0)) + return 1; + + addr += 1; + byte1 = (byte1 >> 8) & 0xff; + if (stb_asm(addr, byte1)) + return 1; + + addr += 1; + byte2 = (byte2 >> 16) & 0xff; + if (stb_asm(addr, byte2)) + return 1; + + addr += 1; + byte3 = (byte3 >> 24) & 0xff; + if (stb_asm(addr, byte3)) + return 1; + + return 0; +} + +extern int fixup_exception(struct pt_regs *regs); + +#define OP_LDH 0xc000 +#define OP_STH 0xd000 +#define OP_LDW 0x8000 +#define OP_STW 0x9000 + +void csky_alignment(struct pt_regs *regs) +{ + int ret; + uint16_t tmp; + uint32_t opcode = 0; + uint32_t rx = 0; + uint32_t rz = 0; + uint32_t imm = 0; + uint32_t addr = 0; + + if (!user_mode(regs)) + goto kernel_area; + + if (!align_usr_enable) { + pr_err("%s user disabled.\n", __func__); + goto bad_area; + } + + align_usr_count++; + + ret = get_user(tmp, (uint16_t *)instruction_pointer(regs)); + if (ret) { + pr_err("%s get_user failed.\n", __func__); + goto bad_area; + } + + goto good_area; + +kernel_area: + if (!align_kern_enable) { + pr_err("%s kernel disabled.\n", __func__); + goto bad_area; + } + + align_kern_count++; + + tmp = *(uint16_t *)instruction_pointer(regs); + +good_area: + opcode = (uint32_t)tmp; + + rx = opcode & 0xf; + imm = (opcode >> 4) & 0xf; + rz = (opcode >> 8) & 0xf; + opcode &= 0xf000; + + if (rx == 0 || rx == 1 || rz == 0 || rz == 1) + goto bad_area; + + switch (opcode) { + case OP_LDH: + addr = get_ptreg(regs, rx) + (imm << 1); + ret = ldh_c(regs, rz, addr); + break; + case OP_LDW: + addr = get_ptreg(regs, rx) + (imm << 2); + ret = ldw_c(regs, rz, addr); + break; + case OP_STH: + addr = get_ptreg(regs, rx) + (imm << 1); + ret = sth_c(regs, rz, addr); + break; + case OP_STW: + addr = get_ptreg(regs, rx) + (imm << 2); + ret = stw_c(regs, rz, addr); + break; + } + + if (ret) + goto bad_area; + + regs->pc += 2; + + return; + +bad_area: + if (!user_mode(regs)) { + if (fixup_exception(regs)) + return; + + bust_spinlocks(1); + pr_alert("%s opcode: %x, rz: %d, rx: %d, imm: %d, addr: %x.\n", + __func__, opcode, rz, rx, imm, addr); + show_regs(regs); + bust_spinlocks(0); + make_task_dead(SIGKILL); + } + + force_sig_fault(SIGBUS, BUS_ADRALN, (void __user *)addr); +} + +static struct ctl_table alignment_tbl[5] = { + { + .procname = "kernel_enable", + .data = &align_kern_enable, + .maxlen = sizeof(align_kern_enable), + .mode = 0666, + .proc_handler = &proc_dointvec + }, + { + .procname = "user_enable", + .data = &align_usr_enable, + .maxlen = sizeof(align_usr_enable), + .mode = 0666, + .proc_handler = &proc_dointvec + }, + { + .procname = "kernel_count", + .data = &align_kern_count, + .maxlen = sizeof(align_kern_count), + .mode = 0666, + .proc_handler = &proc_dointvec + }, + { + .procname = "user_count", + .data = &align_usr_count, + .maxlen = sizeof(align_usr_count), + .mode = 0666, + .proc_handler = &proc_dointvec + }, + {} +}; + +static struct ctl_table sysctl_table[2] = { + { + .procname = "csky_alignment", + .mode = 0555, + .child = alignment_tbl}, + {} +}; + +static struct ctl_path sysctl_path[2] = { + {.procname = "csky"}, + {} +}; + +static int __init csky_alignment_init(void) +{ + register_sysctl_paths(sysctl_path, sysctl_table); + return 0; +} + +arch_initcall(csky_alignment_init); |