327 lines
5.4 KiB
C
327 lines
5.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
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#include <linux/kernel.h>
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#include <linux/uaccess.h>
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#include <linux/ptrace.h>
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static int align_enable = 1;
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static int align_count;
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static inline uint32_t get_ptreg(struct pt_regs *regs, uint32_t rx)
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{
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return rx == 15 ? regs->lr : *((uint32_t *)&(regs->a0) - 2 + rx);
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}
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static inline void put_ptreg(struct pt_regs *regs, uint32_t rx, uint32_t val)
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{
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if (rx == 15)
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regs->lr = val;
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else
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*((uint32_t *)&(regs->a0) - 2 + rx) = val;
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}
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/*
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* Get byte-value from addr and set it to *valp.
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*
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* Success: return 0
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* Failure: return 1
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*/
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static int ldb_asm(uint32_t addr, uint32_t *valp)
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{
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uint32_t val;
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int err;
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if (!access_ok(VERIFY_READ, (void *)addr, 1))
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return 1;
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asm volatile (
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"movi %0, 0\n"
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"1:\n"
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"ldb %1, (%2)\n"
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"br 3f\n"
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"2:\n"
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"movi %0, 1\n"
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"br 3f\n"
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".section __ex_table,\"a\"\n"
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".align 2\n"
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".long 1b, 2b\n"
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".previous\n"
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"3:\n"
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: "=&r"(err), "=r"(val)
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: "r" (addr)
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);
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*valp = val;
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return err;
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}
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/*
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* Put byte-value to addr.
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*
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* Success: return 0
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* Failure: return 1
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*/
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static int stb_asm(uint32_t addr, uint32_t val)
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{
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int err;
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if (!access_ok(VERIFY_WRITE, (void *)addr, 1))
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return 1;
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asm volatile (
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"movi %0, 0\n"
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"1:\n"
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"stb %1, (%2)\n"
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"br 3f\n"
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"2:\n"
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"movi %0, 1\n"
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"br 3f\n"
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".section __ex_table,\"a\"\n"
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".align 2\n"
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".long 1b, 2b\n"
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".previous\n"
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"3:\n"
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: "=&r"(err)
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: "r"(val), "r" (addr)
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);
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return err;
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}
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/*
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* Get half-word from [rx + imm]
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*
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* Success: return 0
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* Failure: return 1
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*/
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static int ldh_c(struct pt_regs *regs, uint32_t rz, uint32_t addr)
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{
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uint32_t byte0, byte1;
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if (ldb_asm(addr, &byte0))
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return 1;
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addr += 1;
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if (ldb_asm(addr, &byte1))
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return 1;
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byte0 |= byte1 << 8;
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put_ptreg(regs, rz, byte0);
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return 0;
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}
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/*
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* Store half-word to [rx + imm]
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*
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* Success: return 0
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* Failure: return 1
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*/
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static int sth_c(struct pt_regs *regs, uint32_t rz, uint32_t addr)
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{
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uint32_t byte0, byte1;
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byte0 = byte1 = get_ptreg(regs, rz);
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byte0 &= 0xff;
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if (stb_asm(addr, byte0))
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return 1;
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addr += 1;
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byte1 = (byte1 >> 8) & 0xff;
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if (stb_asm(addr, byte1))
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return 1;
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return 0;
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}
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/*
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* Get word from [rx + imm]
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*
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* Success: return 0
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* Failure: return 1
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*/
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static int ldw_c(struct pt_regs *regs, uint32_t rz, uint32_t addr)
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{
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uint32_t byte0, byte1, byte2, byte3;
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if (ldb_asm(addr, &byte0))
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return 1;
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addr += 1;
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if (ldb_asm(addr, &byte1))
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return 1;
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addr += 1;
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if (ldb_asm(addr, &byte2))
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return 1;
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addr += 1;
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if (ldb_asm(addr, &byte3))
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return 1;
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byte0 |= byte1 << 8;
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byte0 |= byte2 << 16;
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byte0 |= byte3 << 24;
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put_ptreg(regs, rz, byte0);
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return 0;
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}
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/*
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* Store word to [rx + imm]
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*
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* Success: return 0
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* Failure: return 1
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*/
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static int stw_c(struct pt_regs *regs, uint32_t rz, uint32_t addr)
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{
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uint32_t byte0, byte1, byte2, byte3;
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byte0 = byte1 = byte2 = byte3 = get_ptreg(regs, rz);
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byte0 &= 0xff;
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if (stb_asm(addr, byte0))
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return 1;
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addr += 1;
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byte1 = (byte1 >> 8) & 0xff;
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if (stb_asm(addr, byte1))
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return 1;
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addr += 1;
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byte2 = (byte2 >> 16) & 0xff;
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if (stb_asm(addr, byte2))
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return 1;
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addr += 1;
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byte3 = (byte3 >> 24) & 0xff;
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if (stb_asm(addr, byte3))
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return 1;
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align_count++;
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return 0;
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}
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extern int fixup_exception(struct pt_regs *regs);
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#define OP_LDH 0xc000
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#define OP_STH 0xd000
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#define OP_LDW 0x8000
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#define OP_STW 0x9000
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void csky_alignment(struct pt_regs *regs)
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{
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int ret;
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uint16_t tmp;
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uint32_t opcode = 0;
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uint32_t rx = 0;
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uint32_t rz = 0;
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uint32_t imm = 0;
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uint32_t addr = 0;
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if (!user_mode(regs))
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goto bad_area;
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ret = get_user(tmp, (uint16_t *)instruction_pointer(regs));
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if (ret) {
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pr_err("%s get_user failed.\n", __func__);
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goto bad_area;
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}
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opcode = (uint32_t)tmp;
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rx = opcode & 0xf;
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imm = (opcode >> 4) & 0xf;
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rz = (opcode >> 8) & 0xf;
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opcode &= 0xf000;
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if (rx == 0 || rx == 1 || rz == 0 || rz == 1)
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goto bad_area;
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switch (opcode) {
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case OP_LDH:
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addr = get_ptreg(regs, rx) + (imm << 1);
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ret = ldh_c(regs, rz, addr);
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break;
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case OP_LDW:
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addr = get_ptreg(regs, rx) + (imm << 2);
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ret = ldw_c(regs, rz, addr);
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break;
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case OP_STH:
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addr = get_ptreg(regs, rx) + (imm << 1);
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ret = sth_c(regs, rz, addr);
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break;
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case OP_STW:
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addr = get_ptreg(regs, rx) + (imm << 2);
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ret = stw_c(regs, rz, addr);
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break;
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}
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if (ret)
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goto bad_area;
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regs->pc += 2;
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return;
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bad_area:
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if (!user_mode(regs)) {
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if (fixup_exception(regs))
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return;
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bust_spinlocks(1);
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pr_alert("%s opcode: %x, rz: %d, rx: %d, imm: %d, addr: %x.\n",
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__func__, opcode, rz, rx, imm, addr);
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show_regs(regs);
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bust_spinlocks(0);
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do_exit(SIGKILL);
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}
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force_sig_fault(SIGBUS, BUS_ADRALN, (void __user *)addr, current);
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}
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static struct ctl_table alignment_tbl[4] = {
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{
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.procname = "enable",
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.data = &align_enable,
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.maxlen = sizeof(align_enable),
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.mode = 0666,
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.proc_handler = &proc_dointvec
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},
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{
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.procname = "count",
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.data = &align_count,
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.maxlen = sizeof(align_count),
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.mode = 0666,
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.proc_handler = &proc_dointvec
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},
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{}
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};
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static struct ctl_table sysctl_table[2] = {
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{
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.procname = "csky_alignment",
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.mode = 0555,
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.child = alignment_tbl},
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{}
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};
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static struct ctl_path sysctl_path[2] = {
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{.procname = "csky"},
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{}
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};
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static int __init csky_alignment_init(void)
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{
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register_sysctl_paths(sysctl_path, sysctl_table);
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return 0;
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}
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arch_initcall(csky_alignment_init);
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