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MIPS: Print correct PC in trace dump after NMI exception

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An NMI exception delivered from YAMON delivers the PC in ErrorPC
instead of EPC. It's also necessary to clear the Status.BEV
bit for the page fault exception handler to work properly.

[ralf@linux-mips: Let the assembler do the loading of the mask value rather
than the convoluted explicit %hi/%lo manual relocation sequence from the
original patch.]

Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6035/
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Markos Chandras <markos.chandras@imgtec.com>
Patchwork: https://patchwork.linux-mips.org/patch/6084/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Leonid Yegoshin 2013-10-08 12:39:31 +01:00 committed by Ralf Baechle
parent d9f897c912
commit 83e4da1ed4
2 changed files with 22 additions and 5 deletions
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14
arch/mips/kernel/genex.S
View File

@ -374,12 +374,20 @@ NESTED(except_vec_nmi, 0, sp)
NESTED(nmi_handler, PT_SIZE, sp)
.set push
.set noat
/*
* Clear ERL - restore segment mapping
* Clear BEV - required for page fault exception handler to work
*/
mfc0 k0, CP0_STATUS
ori k0, k0, ST0_EXL
li k1, ~(ST0_BEV | ST0_ERL)
and k0, k0, k1
mtc0 k0, CP0_STATUS
_ehb
SAVE_ALL
move a0, sp
jal nmi_exception_handler
RESTORE_ALL
.set mips3
eret
/* nmi_exception_handler never returns */
.set pop
END(nmi_handler)

13
arch/mips/kernel/traps.c
View File

@ -330,6 +330,7 @@ void show_regs(struct pt_regs *regs)
void show_registers(struct pt_regs *regs)
{
const int field = 2 * sizeof(unsigned long);
mm_segment_t old_fs = get_fs();
__show_regs(regs);
print_modules();
@ -344,9 +345,13 @@ void show_registers(struct pt_regs *regs)
printk("*HwTLS: %0*lx\n", field, tls);
}
if (!user_mode(regs))
/* Necessary for getting the correct stack content */
set_fs(KERNEL_DS);
show_stacktrace(current, regs);
show_code((unsigned int __user *) regs->cp0_epc);
printk("\n");
set_fs(old_fs);
}
static int regs_to_trapnr(struct pt_regs *regs)
@ -1488,10 +1493,14 @@ int register_nmi_notifier(struct notifier_block *nb)
void __noreturn nmi_exception_handler(struct pt_regs *regs)
{
char str[100];
raw_notifier_call_chain(&nmi_chain, 0, regs);
bust_spinlocks(1);
printk("NMI taken!!!!\n");
die("NMI", regs);
snprintf(str, 100, "CPU%d NMI taken, CP0_EPC=%lx\n",
smp_processor_id(), regs->cp0_epc);
regs->cp0_epc = read_c0_errorepc();
die(str, regs);
}
#define VECTORSPACING 0x100 /* for EI/VI mode */