On P9, trying to use data breakpoints throws the splat shown below (*).
This is because the check for a data breakpoint in DSISR is in
do_hash_page(). Move this check to handle_page_fault() so as to catch
data breakpoints in both hash and radix MMU modes.
While at it, also remove the label '11' that was made redundant by
commit a546498f3bf9aa ("powerpc: Call do_page_fault() with interrupts
off")
(*)
Unable to handle kernel paging request for data at address
0xc000000000e19218
Faulting instruction address: 0xc0000000001155e8
cpu 0x0: Vector: 300 (Data Access) at [c0000000ef1e7b20]
pc: c0000000001155e8: find_pid_ns+0x48/0xe0
lr: c000000000116ac4: find_task_by_vpid+0x44/0x90
sp: c0000000ef1e7da0
msr: 9000000000009033
dar: c000000000e19218
dsisr: 400000
current = 0xc0000000f1f59700
paca = 0xc00000000fd40000 softe: 0 irq_happened: 0x01
pid = 1192, comm = sh
Linux version 4.12.0-rc3-nnr (root@ea605ec2993c) (gcc version 5.4.0
20160609 (Ubuntu/IBM 5.4.0-6ubuntu1~16.04.1) ) #74 SMP Tue Jun 13 16:52:49 UTC
2017
enter ? for help
[c0000000ef1e7dc0] c000000000116ac4 find_task_by_vpid+0x44/0x90
[c0000000ef1e7de0] c000000000108800 SyS_setpgid+0x80/0x220
[c0000000ef1e7e30] c00000000000ba6c system_call+0x38/0xfc
--- Exception: c01 (System Call) at 00007fff94480890
SP (7fffd91e7260) is in userspace
Fixes: caca285e5ab4a ("powerpc/mm/radix: Use STD_MMU_64 to properly
isolate hash related code")
Reported-by: Shriya R. Kulkarni <shriy...@in.ibm.com>
Signed-off-by: Naveen N. Rao <naveen.n....@linux.vnet.ibm.com>
---
arch/powerpc/kernel/exceptions-64s.S | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/kernel/exceptions-64s.S
b/arch/powerpc/kernel/exceptions-64s.S
index ae418b85c17c..17ee701b8336 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -1411,10 +1411,8 @@ USE_TEXT_SECTION()
.balign IFETCH_ALIGN_BYTES
do_hash_page:
#ifdef CONFIG_PPC_STD_MMU_64
- andis. r0,r4,0xa410 /* weird error? */
+ andis. r0,r4,0xa450 /* weird error? */
bne- handle_page_fault /* if not, try to insert a HPTE */
- andis. r0,r4,DSISR_DABRMATCH@h
- bne- handle_dabr_fault
CURRENT_THREAD_INFO(r11, r1)
lwz r0,TI_PREEMPT(r11) /* If we're in an "NMI" */
andis. r0,r0,NMI_MASK@h /* (i.e. an irq when soft-disabled) */
@@ -1442,7 +1440,9 @@ do_hash_page:
/* Here we have a page fault that hash_page can't handle. */
handle_page_fault:
-11: ld r4,_DAR(r1)
+ andis. r0,r4,DSISR_DABRMATCH@h
+ bne- handle_dabr_fault
+ ld r4,_DAR(r1)
ld r5,_DSISR(r1)
addi r3,r1,STACK_FRAME_OVERHEAD
bl do_page_fault
--
2.12.2
