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authorLeonid Yegoshin <Leonid.Yegoshin@imgtec.com>2013-10-08 12:39:31 +0100
committerRalf Baechle <ralf@linux-mips.org>2013-10-29 21:25:35 +0100
commit83e4da1ed45441c3aadc39ac47d33895ab23c841 (patch)
tree50bef4e0e7482196fb59a6b87845a4c00dd183ae /arch/mips/kernel
parentd9f897c912b4108076afb00036a139e3b8144a64 (diff)
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>
Diffstat (limited to 'arch/mips/kernel')
-rw-r--r--arch/mips/kernel/genex.S14
-rw-r--r--arch/mips/kernel/traps.c13
2 files changed, 22 insertions, 5 deletions
diff --git a/arch/mips/kernel/genex.S b/arch/mips/kernel/genex.S
index 31fa856829cb..47d7583cd67f 100644
--- a/arch/mips/kernel/genex.S
+++ b/arch/mips/kernel/genex.S
@@ -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)
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index f2ae9cb57ff0..a17b6efb8bfe 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -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 */

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