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// SPDX-License-Identifier: GPL-2.0
/*
* Handle unaligned accesses by emulation.
*
* Copyright (C) 2020-2022 Loongson Technology Corporation Limited
*
* Derived from MIPS:
* Copyright (C) 1996, 1998, 1999, 2002 by Ralf Baechle
* Copyright (C) 1999 Silicon Graphics, Inc.
* Copyright (C) 2014 Imagination Technologies Ltd.
*/
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/signal.h>
#include <linux/debugfs.h>
#include <linux/perf_event.h>
#include <asm/asm.h>
#include <asm/branch.h>
#include <asm/fpu.h>
#include <asm/inst.h>
#include "access-helper.h"
#ifdef CONFIG_DEBUG_FS
static u32 unaligned_instructions_user;
static u32 unaligned_instructions_kernel;
#endif
static inline unsigned long read_fpr(unsigned int idx)
{
#define READ_FPR(idx, __value) \
__asm__ __volatile__("movfr2gr.d %0, $f"#idx"\n\t" : "=r"(__value));
unsigned long __value;
switch (idx) {
case 0:
READ_FPR(0, __value);
break;
case 1:
READ_FPR(1, __value);
break;
case 2:
READ_FPR(2, __value);
break;
case 3:
READ_FPR(3, __value);
break;
case 4:
READ_FPR(4, __value);
break;
case 5:
READ_FPR(5, __value);
break;
case 6:
READ_FPR(6, __value);
break;
case 7:
READ_FPR(7, __value);
break;
case 8:
READ_FPR(8, __value);
break;
case 9:
READ_FPR(9, __value);
break;
case 10:
READ_FPR(10, __value);
break;
case 11:
READ_FPR(11, __value);
break;
case 12:
READ_FPR(12, __value);
break;
case 13:
READ_FPR(13, __value);
break;
case 14:
READ_FPR(14, __value);
break;
case 15:
READ_FPR(15, __value);
break;
case 16:
READ_FPR(16, __value);
break;
case 17:
READ_FPR(17, __value);
break;
case 18:
READ_FPR(18, __value);
break;
case 19:
READ_FPR(19, __value);
break;
case 20:
READ_FPR(20, __value);
break;
case 21:
READ_FPR(21, __value);
break;
case 22:
READ_FPR(22, __value);
break;
case 23:
READ_FPR(23, __value);
break;
case 24:
READ_FPR(24, __value);
break;
case 25:
READ_FPR(25, __value);
break;
case 26:
READ_FPR(26, __value);
break;
case 27:
READ_FPR(27, __value);
break;
case 28:
READ_FPR(28, __value);
break;
case 29:
READ_FPR(29, __value);
break;
case 30:
READ_FPR(30, __value);
break;
case 31:
READ_FPR(31, __value);
break;
default:
panic("unexpected idx '%d'", idx);
}
#undef READ_FPR
return __value;
}
static inline void write_fpr(unsigned int idx, unsigned long value)
{
#define WRITE_FPR(idx, value) \
__asm__ __volatile__("movgr2fr.d $f"#idx", %0\n\t" :: "r"(value));
switch (idx) {
case 0:
WRITE_FPR(0, value);
break;
case 1:
WRITE_FPR(1, value);
break;
case 2:
WRITE_FPR(2, value);
break;
case 3:
WRITE_FPR(3, value);
break;
case 4:
WRITE_FPR(4, value);
break;
case 5:
WRITE_FPR(5, value);
break;
case 6:
WRITE_FPR(6, value);
break;
case 7:
WRITE_FPR(7, value);
break;
case 8:
WRITE_FPR(8, value);
break;
case 9:
WRITE_FPR(9, value);
break;
case 10:
WRITE_FPR(10, value);
break;
case 11:
WRITE_FPR(11, value);
break;
case 12:
WRITE_FPR(12, value);
break;
case 13:
WRITE_FPR(13, value);
break;
case 14:
WRITE_FPR(14, value);
break;
case 15:
WRITE_FPR(15, value);
break;
case 16:
WRITE_FPR(16, value);
break;
case 17:
WRITE_FPR(17, value);
break;
case 18:
WRITE_FPR(18, value);
break;
case 19:
WRITE_FPR(19, value);
break;
case 20:
WRITE_FPR(20, value);
break;
case 21:
WRITE_FPR(21, value);
break;
case 22:
WRITE_FPR(22, value);
break;
case 23:
WRITE_FPR(23, value);
break;
case 24:
WRITE_FPR(24, value);
break;
case 25:
WRITE_FPR(25, value);
break;
case 26:
WRITE_FPR(26, value);
break;
case 27:
WRITE_FPR(27, value);
break;
case 28:
WRITE_FPR(28, value);
break;
case 29:
WRITE_FPR(29, value);
break;
case 30:
WRITE_FPR(30, value);
break;
case 31:
WRITE_FPR(31, value);
break;
default:
panic("unexpected idx '%d'", idx);
}
#undef WRITE_FPR
}
void emulate_load_store_insn(struct pt_regs *regs, void __user *addr, unsigned int *pc)
{
bool fp = false;
bool sign, write;
bool user = user_mode(regs);
unsigned int res, size = 0;
unsigned long value = 0;
union loongarch_instruction insn;
perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, regs, 0);
__get_inst(&insn.word, pc, user);
switch (insn.reg2i12_format.opcode) {
case ldh_op:
size = 2;
sign = true;
write = false;
break;
case ldhu_op:
size = 2;
sign = false;
write = false;
break;
case sth_op:
size = 2;
sign = true;
write = true;
break;
case ldw_op:
size = 4;
sign = true;
write = false;
break;
case ldwu_op:
size = 4;
sign = false;
write = false;
break;
case stw_op:
size = 4;
sign = true;
write = true;
break;
case ldd_op:
size = 8;
sign = true;
write = false;
break;
case std_op:
size = 8;
sign = true;
write = true;
break;
case flds_op:
size = 4;
fp = true;
sign = true;
write = false;
break;
case fsts_op:
size = 4;
fp = true;
sign = true;
write = true;
break;
case fldd_op:
size = 8;
fp = true;
sign = true;
write = false;
break;
case fstd_op:
size = 8;
fp = true;
sign = true;
write = true;
break;
}
switch (insn.reg2i14_format.opcode) {
case ldptrw_op:
size = 4;
sign = true;
write = false;
break;
case stptrw_op:
size = 4;
sign = true;
write = true;
break;
case ldptrd_op:
size = 8;
sign = true;
write = false;
break;
case stptrd_op:
size = 8;
sign = true;
write = true;
break;
}
switch (insn.reg3_format.opcode) {
case ldxh_op:
size = 2;
sign = true;
write = false;
break;
case ldxhu_op:
size = 2;
sign = false;
write = false;
break;
case stxh_op:
size = 2;
sign = true;
write = true;
break;
case ldxw_op:
size = 4;
sign = true;
write = false;
break;
case ldxwu_op:
size = 4;
sign = false;
write = false;
break;
case stxw_op:
size = 4;
sign = true;
write = true;
break;
case ldxd_op:
size = 8;
sign = true;
write = false;
break;
case stxd_op:
size = 8;
sign = true;
write = true;
break;
case fldxs_op:
size = 4;
fp = true;
sign = true;
write = false;
break;
case fstxs_op:
size = 4;
fp = true;
sign = true;
write = true;
break;
case fldxd_op:
size = 8;
fp = true;
sign = true;
write = false;
break;
case fstxd_op:
size = 8;
fp = true;
sign = true;
write = true;
break;
}
if (!size)
goto sigbus;
if (user && !access_ok(addr, size))
goto sigbus;
if (!write) {
res = unaligned_read(addr, &value, size, sign);
if (res)
goto fault;
/* Rd is the same field in any formats */
if (!fp)
regs->regs[insn.reg3_format.rd] = value;
else {
if (is_fpu_owner())
write_fpr(insn.reg3_format.rd, value);
else
set_fpr64(¤t->thread.fpu.fpr[insn.reg3_format.rd], 0, value);
}
} else {
/* Rd is the same field in any formats */
if (!fp)
value = regs->regs[insn.reg3_format.rd];
else {
if (is_fpu_owner())
value = read_fpr(insn.reg3_format.rd);
else
value = get_fpr64(¤t->thread.fpu.fpr[insn.reg3_format.rd], 0);
}
res = unaligned_write(addr, value, size);
if (res)
goto fault;
}
#ifdef CONFIG_DEBUG_FS
if (user)
unaligned_instructions_user++;
else
unaligned_instructions_kernel++;
#endif
compute_return_era(regs);
return;
fault:
/* Did we have an exception handler installed? */
if (fixup_exception(regs))
return;
die_if_kernel("Unhandled kernel unaligned access", regs);
force_sig(SIGSEGV);
return;
sigbus:
die_if_kernel("Unhandled kernel unaligned access", regs);
force_sig(SIGBUS);
return;
}
#ifdef CONFIG_DEBUG_FS
static int __init debugfs_unaligned(void)
{
struct dentry *d;
d = debugfs_create_dir("loongarch", NULL);
if (IS_ERR_OR_NULL(d))
return -ENOMEM;
debugfs_create_u32("unaligned_instructions_user",
S_IRUGO, d, &unaligned_instructions_user);
debugfs_create_u32("unaligned_instructions_kernel",
S_IRUGO, d, &unaligned_instructions_kernel);
return 0;
}
arch_initcall(debugfs_unaligned);
#endif
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