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| author | Paul Mackerras <paulus@samba.org> | 2011-05-01 19:46:44 +0000 |
|---|---|---|
| committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2011-05-04 15:19:27 +1000 |
| commit | 1977b502120d44b9b4897703adfb2e2fab346880 (patch) | |
| tree | dfe0e5cc29b409e7638b5e33528b7c4bc003f5e7 /arch/powerpc/kernel/exceptions-64s.S | |
| parent | 851d2e2fe8dbcbe3afcad6fc4569c881d8ad4ce9 (diff) | |
| download | lwn-1977b502120d44b9b4897703adfb2e2fab346880.tar.gz lwn-1977b502120d44b9b4897703adfb2e2fab346880.zip | |
powerpc: Save register r9-r13 values accurately on interrupt with bad stack
When we take an interrupt or exception from kernel mode and the stack
pointer is obviously not a kernel address (i.e. the top bit is 0), we
switch to an emergency stack, save register values and panic. However,
on 64-bit server machines, we don't actually save the values of r9 - r13
at the time of the interrupt, but rather values corrupted by the
exception entry code for r12-r13, and nothing at all for r9-r11.
This fixes it by passing a pointer to the register save area in the paca
through to the bad_stack code in r3. The register values are saved in
one of the paca register save areas (depending on which exception this
is). Using the pointer in r3, the bad_stack code now retrieves the
saved values of r9 - r13 and stores them in the exception frame on the
emergency stack. This also stores the normal exception frame marker
("regshere") in the exception frame.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/kernel/exceptions-64s.S')
| -rw-r--r-- | arch/powerpc/kernel/exceptions-64s.S | 20 |
1 files changed, 17 insertions, 3 deletions
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index 226cc8c62224..27ca8b7c6002 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -461,9 +461,20 @@ bad_stack: std r12,_XER(r1) SAVE_GPR(0,r1) SAVE_GPR(2,r1) - SAVE_4GPRS(3,r1) - SAVE_2GPRS(7,r1) - SAVE_10GPRS(12,r1) + ld r10,EX_R3(r3) + std r10,GPR3(r1) + SAVE_GPR(4,r1) + SAVE_4GPRS(5,r1) + ld r9,EX_R9(r3) + ld r10,EX_R10(r3) + SAVE_2GPRS(9,r1) + ld r9,EX_R11(r3) + ld r10,EX_R12(r3) + ld r11,EX_R13(r3) + std r9,GPR11(r1) + std r10,GPR12(r1) + std r11,GPR13(r1) + SAVE_8GPRS(14,r1) SAVE_10GPRS(22,r1) lhz r12,PACA_TRAP_SAVE(r13) std r12,_TRAP(r1) @@ -472,6 +483,9 @@ bad_stack: li r12,0 std r12,0(r11) ld r2,PACATOC(r13) + ld r11,exception_marker@toc(r2) + std r12,RESULT(r1) + std r11,STACK_FRAME_OVERHEAD-16(r1) 1: addi r3,r1,STACK_FRAME_OVERHEAD bl .kernel_bad_stack b 1b |