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linux/arch/mips/loongson64/cop2-ex.c
Huacai Chen 01ce6d4d2c MIPS: Loongson-3: Fix fp register access if MSA enabled 
If MSA is enabled, FPU_REG_WIDTH is 128 rather than 64, then get_fpr64()
/set_fpr64() in the original unaligned instruction emulation code access
the wrong fp registers. This is because the current code doesn't specify
the correct index field, so fix it.

Fixes: f83e4f9896 ("MIPS: Loongson-3: Add some unaligned instructions emulation")
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Signed-off-by: Pei Huang <huangpei@loongson.cn>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
2020-09-22 13:07:22 +02:00

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/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 2014 Lemote Corporation.
* written by Huacai Chen <chenhc@lemote.com>
*
* based on arch/mips/cavium-octeon/cpu.c
* Copyright (C) 2009 Wind River Systems,
* written by Ralf Baechle <ralf@linux-mips.org>
*/
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/notifier.h>
#include <linux/ptrace.h>
#include <linux/uaccess.h>
#include <linux/sched/signal.h>
#include <asm/fpu.h>
#include <asm/cop2.h>
#include <asm/inst.h>
#include <asm/branch.h>
#include <asm/current.h>
#include <asm/mipsregs.h>
#include <asm/unaligned-emul.h>
static int loongson_cu2_call(struct notifier_block *nfb, unsigned long action,
void *data)
{
unsigned int res, fpu_owned;
unsigned long ra, value, value_next;
union mips_instruction insn;
int fr = !test_thread_flag(TIF_32BIT_FPREGS);
struct pt_regs *regs = (struct pt_regs *)data;
void __user *addr = (void __user *)regs->cp0_badvaddr;
unsigned int __user *pc = (unsigned int __user *)exception_epc(regs);
ra = regs->regs[31];
__get_user(insn.word, pc);
switch (action) {
case CU2_EXCEPTION:
preempt_disable();
fpu_owned = __is_fpu_owner();
if (!fr)
set_c0_status(ST0_CU1 | ST0_CU2);
else
set_c0_status(ST0_CU1 | ST0_CU2 | ST0_FR);
enable_fpu_hazard();
KSTK_STATUS(current) |= (ST0_CU1 | ST0_CU2);
if (fr)
KSTK_STATUS(current) |= ST0_FR;
else
KSTK_STATUS(current) &= ~ST0_FR;
/* If FPU is owned, we needn't init or restore fp */
if (!fpu_owned) {
set_thread_flag(TIF_USEDFPU);
init_fp_ctx(current);
_restore_fp(current);
}
preempt_enable();
return NOTIFY_STOP; /* Don't call default notifier */
case CU2_LWC2_OP:
if (insn.loongson3_lswc2_format.ls == 0)
goto sigbus;
if (insn.loongson3_lswc2_format.fr == 0) { /* gslq */
if (!access_ok(addr, 16))
goto sigbus;
LoadDW(addr, value, res);
if (res)
goto fault;
LoadDW(addr + 8, value_next, res);
if (res)
goto fault;
regs->regs[insn.loongson3_lswc2_format.rt] = value;
regs->regs[insn.loongson3_lswc2_format.rq] = value_next;
compute_return_epc(regs);
} else { /* gslqc1 */
if (!access_ok(addr, 16))
goto sigbus;
lose_fpu(1);
LoadDW(addr, value, res);
if (res)
goto fault;
LoadDW(addr + 8, value_next, res);
if (res)
goto fault;
set_fpr64(&current->thread.fpu.fpr[insn.loongson3_lswc2_format.rt], 0, value);
set_fpr64(&current->thread.fpu.fpr[insn.loongson3_lswc2_format.rq], 0, value_next);
compute_return_epc(regs);
own_fpu(1);
}
return NOTIFY_STOP; /* Don't call default notifier */
case CU2_SWC2_OP:
if (insn.loongson3_lswc2_format.ls == 0)
goto sigbus;
if (insn.loongson3_lswc2_format.fr == 0) { /* gssq */
if (!access_ok(addr, 16))
goto sigbus;
/* write upper 8 bytes first */
value_next = regs->regs[insn.loongson3_lswc2_format.rq];
StoreDW(addr + 8, value_next, res);
if (res)
goto fault;
value = regs->regs[insn.loongson3_lswc2_format.rt];
StoreDW(addr, value, res);
if (res)
goto fault;
compute_return_epc(regs);
} else { /* gssqc1 */
if (!access_ok(addr, 16))
goto sigbus;
lose_fpu(1);
value_next = get_fpr64(&current->thread.fpu.fpr[insn.loongson3_lswc2_format.rq], 0);
StoreDW(addr + 8, value_next, res);
if (res)
goto fault;
value = get_fpr64(&current->thread.fpu.fpr[insn.loongson3_lswc2_format.rt], 0);
StoreDW(addr, value, res);
if (res)
goto fault;
compute_return_epc(regs);
own_fpu(1);
}
return NOTIFY_STOP; /* Don't call default notifier */
case CU2_LDC2_OP:
switch (insn.loongson3_lsdc2_format.opcode1) {
/*
* Loongson-3 overridden ldc2 instructions.
* opcode1 instruction
* 0x1 gslhx: load 2 bytes to GPR
* 0x2 gslwx: load 4 bytes to GPR
* 0x3 gsldx: load 8 bytes to GPR
* 0x6 gslwxc1: load 4 bytes to FPR
* 0x7 gsldxc1: load 8 bytes to FPR
*/
case 0x1:
if (!access_ok(addr, 2))
goto sigbus;
LoadHW(addr, value, res);
if (res)
goto fault;
compute_return_epc(regs);
regs->regs[insn.loongson3_lsdc2_format.rt] = value;
break;
case 0x2:
if (!access_ok(addr, 4))
goto sigbus;
LoadW(addr, value, res);
if (res)
goto fault;
compute_return_epc(regs);
regs->regs[insn.loongson3_lsdc2_format.rt] = value;
break;
case 0x3:
if (!access_ok(addr, 8))
goto sigbus;
LoadDW(addr, value, res);
if (res)
goto fault;
compute_return_epc(regs);
regs->regs[insn.loongson3_lsdc2_format.rt] = value;
break;
case 0x6:
die_if_kernel("Unaligned FP access in kernel code", regs);
BUG_ON(!used_math());
if (!access_ok(addr, 4))
goto sigbus;
lose_fpu(1);
LoadW(addr, value, res);
if (res)
goto fault;
set_fpr64(&current->thread.fpu.fpr[insn.loongson3_lsdc2_format.rt], 0, value);
compute_return_epc(regs);
own_fpu(1);
break;
case 0x7:
die_if_kernel("Unaligned FP access in kernel code", regs);
BUG_ON(!used_math());
if (!access_ok(addr, 8))
goto sigbus;
lose_fpu(1);
LoadDW(addr, value, res);
if (res)
goto fault;
set_fpr64(&current->thread.fpu.fpr[insn.loongson3_lsdc2_format.rt], 0, value);
compute_return_epc(regs);
own_fpu(1);
break;
}
return NOTIFY_STOP; /* Don't call default notifier */
case CU2_SDC2_OP:
switch (insn.loongson3_lsdc2_format.opcode1) {
/*
* Loongson-3 overridden sdc2 instructions.
* opcode1 instruction
* 0x1 gsshx: store 2 bytes from GPR
* 0x2 gsswx: store 4 bytes from GPR
* 0x3 gssdx: store 8 bytes from GPR
* 0x6 gsswxc1: store 4 bytes from FPR
* 0x7 gssdxc1: store 8 bytes from FPR
*/
case 0x1:
if (!access_ok(addr, 2))
goto sigbus;
compute_return_epc(regs);
value = regs->regs[insn.loongson3_lsdc2_format.rt];
StoreHW(addr, value, res);
if (res)
goto fault;
break;
case 0x2:
if (!access_ok(addr, 4))
goto sigbus;
compute_return_epc(regs);
value = regs->regs[insn.loongson3_lsdc2_format.rt];
StoreW(addr, value, res);
if (res)
goto fault;
break;
case 0x3:
if (!access_ok(addr, 8))
goto sigbus;
compute_return_epc(regs);
value = regs->regs[insn.loongson3_lsdc2_format.rt];
StoreDW(addr, value, res);
if (res)
goto fault;
break;
case 0x6:
die_if_kernel("Unaligned FP access in kernel code", regs);
BUG_ON(!used_math());
if (!access_ok(addr, 4))
goto sigbus;
lose_fpu(1);
value = get_fpr64(&current->thread.fpu.fpr[insn.loongson3_lsdc2_format.rt], 0);
StoreW(addr, value, res);
if (res)
goto fault;
compute_return_epc(regs);
own_fpu(1);
break;
case 0x7:
die_if_kernel("Unaligned FP access in kernel code", regs);
BUG_ON(!used_math());
if (!access_ok(addr, 8))
goto sigbus;
lose_fpu(1);
value = get_fpr64(&current->thread.fpu.fpr[insn.loongson3_lsdc2_format.rt], 0);
StoreDW(addr, value, res);
if (res)
goto fault;
compute_return_epc(regs);
own_fpu(1);
break;
}
return NOTIFY_STOP; /* Don't call default notifier */
}
return NOTIFY_OK; /* Let default notifier send signals */
fault:
/* roll back jump/branch */
regs->regs[31] = ra;
regs->cp0_epc = (unsigned long)pc;
/* Did we have an exception handler installed? */
if (fixup_exception(regs))
return NOTIFY_STOP; /* Don't call default notifier */
die_if_kernel("Unhandled kernel unaligned access", regs);
force_sig(SIGSEGV);
return NOTIFY_STOP; /* Don't call default notifier */
sigbus:
die_if_kernel("Unhandled kernel unaligned access", regs);
force_sig(SIGBUS);
return NOTIFY_STOP; /* Don't call default notifier */
}
static int __init loongson_cu2_setup(void)
{
return cu2_notifier(loongson_cu2_call, 0);
}
early_initcall(loongson_cu2_setup);
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