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MIPS: Print correct PC in trace dump after NMI exception 

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 */