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| author | Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> | 2017-06-13 21:42:00 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2017-06-16 12:49:43 +0300 |
| commit | d89ba5353f301971dd7d2f9fdf25c4432728f38e (patch) | |
| tree | f6d6a0b27dc9f81daa893d0c5722830d053a5393 /arch/powerpc | |
| parent | c05b8c4474c03026aaa7f8872e78369f69f1bb08 (diff) | |
| download | linux-d89ba5353f301971dd7d2f9fdf25c4432728f38e.tar.xz | |
powerpc/64s: Handle data breakpoints in Radix mode
On Power9, 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(), which is not called when in Radix mode.
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
Move the check to handle_page_fault() so as to catch data breakpoints
in both Hash and Radix MMU modes.
We have to change the check in do_hash_page() against 0xa410 to use
0xa450, so as to include the value of (DSISR_DABRMATCH << 16).
There are two sites that call handle_page_fault() when in Radix, both
already pass DSISR in r4.
Fixes: caca285e5ab4 ("powerpc/mm/radix: Use STD_MMU_64 to properly isolate hash related code")
Cc: stable@vger.kernel.org # v4.7+
Reported-by: Shriya R. Kulkarni <shriykul@in.ibm.com>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
[mpe: Fix the fall-through case on hash, we need to reload DSISR]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc')
| -rw-r--r-- | arch/powerpc/kernel/exceptions-64s.S | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index ae418b85c17c..b886795060fd 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) */ @@ -1438,11 +1436,16 @@ do_hash_page: /* Error */ blt- 13f + + /* Reload DSISR into r4 for the DABR check below */ + ld r4,_DSISR(r1) #endif /* CONFIG_PPC_STD_MMU_64 */ /* Here we have a page fault that hash_page can't handle. */ handle_page_fault: -11: ld r4,_DAR(r1) +11: 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 |