mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-23 01:10:04 +00:00
ARC: Re-enable MMU upon Machine Check exception
I recently came upon a scenario where I would get a double fault machine check exception tiriggered by a kernel module. However the ensuing crash stacktrace (ksym lookup) was not working correctly. Turns out that machine check auto-disables MMU while modules are allocated in kernel vaddr spapce. This patch re-enables the MMU before start printing the stacktrace making stacktracing of modules work upon a fatal exception. Cc: stable@kernel.org Signed-off-by: Jose Abreu <joabreu@synopsys.com> Reviewed-by: Alexey Brodkin <abrodkin@synopsys.com> Signed-off-by: Vineet Gupta <vgupta@synopsys.com> [vgupta: moved code into low level handler to avoid in 2 places]
This commit is contained in:
parent
aa7e3a5e8b
commit
1ee55a8f7f
2 changed files with 6 additions and 3 deletions
|
@ -92,6 +92,12 @@ ENTRY(EV_MachineCheck)
|
||||||
lr r0, [efa]
|
lr r0, [efa]
|
||||||
mov r1, sp
|
mov r1, sp
|
||||||
|
|
||||||
|
; hardware auto-disables MMU, re-enable it to allow kernel vaddr
|
||||||
|
; access for say stack unwinding of modules for crash dumps
|
||||||
|
lr r3, [ARC_REG_PID]
|
||||||
|
or r3, r3, MMU_ENABLE
|
||||||
|
sr r3, [ARC_REG_PID]
|
||||||
|
|
||||||
lsr r3, r2, 8
|
lsr r3, r2, 8
|
||||||
bmsk r3, r3, 7
|
bmsk r3, r3, 7
|
||||||
brne r3, ECR_C_MCHK_DUP_TLB, 1f
|
brne r3, ECR_C_MCHK_DUP_TLB, 1f
|
||||||
|
|
|
@ -908,9 +908,6 @@ void do_tlb_overlap_fault(unsigned long cause, unsigned long address,
|
||||||
|
|
||||||
local_irq_save(flags);
|
local_irq_save(flags);
|
||||||
|
|
||||||
/* re-enable the MMU */
|
|
||||||
write_aux_reg(ARC_REG_PID, MMU_ENABLE | read_aux_reg(ARC_REG_PID));
|
|
||||||
|
|
||||||
/* loop thru all sets of TLB */
|
/* loop thru all sets of TLB */
|
||||||
for (set = 0; set < mmu->sets; set++) {
|
for (set = 0; set < mmu->sets; set++) {
|
||||||
|
|
||||||
|
|
Loading…
Reference in a new issue