96d4f267e4
Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument
of the user address range verification function since we got rid of the
old racy i386-only code to walk page tables by hand.
It existed because the original 80386 would not honor the write protect
bit when in kernel mode, so you had to do COW by hand before doing any
user access. But we haven't supported that in a long time, and these
days the 'type' argument is a purely historical artifact.
A discussion about extending 'user_access_begin()' to do the range
checking resulted this patch, because there is no way we're going to
move the old VERIFY_xyz interface to that model. And it's best done at
the end of the merge window when I've done most of my merges, so let's
just get this done once and for all.
This patch was mostly done with a sed-script, with manual fix-ups for
the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form.
There were a couple of notable cases:
- csky still had the old "verify_area()" name as an alias.
- the iter_iov code had magical hardcoded knowledge of the actual
values of VERIFY_{READ,WRITE} (not that they mattered, since nothing
really used it)
- microblaze used the type argument for a debug printout
but other than those oddities this should be a total no-op patch.
I tried to fix up all architectures, did fairly extensive grepping for
access_ok() uses, and the changes are trivial, but I may have missed
something. Any missed conversion should be trivially fixable, though.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
327 lines
5.3 KiB
C
327 lines
5.3 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((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((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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