Excerpts from Christian Zigotzky's message of May 14, 2021 6:20 am:
> On 13 May 2021 at 07:00pm, Christophe Leroy wrote:
>>
>> Ah yes, I remember this problem.
>>
>> Can you select CONFIG_VIRT_CPU_ACCOUNTING_GEN in your configuration ?
>>
>> Otherwise, I can try to fix the branch.
>>
>> Christophe
> I selected this. After that it compiles.
>
> 1. git bisect good - Xorg restarts again and again
> Output: [f9aa0ac1e9e82b60401ad567bdabc30598325bc1] Revert
> "powerpc/64e/interrupt: use new interrupt return"
> 2. git bisect good - Xorg restarts again and again
> Output: [cd6d259a14704741bf0cd1dcadb84c0de22d7f77] Revert
> "powerpc/64e/interrupt: always save nvgprs on interrupt"
> 3. git bisect bad - Xorg works
> Output: [9bfa20ef2ae54d3b9088dfbcde4ef97062cf5ef2] Revert
> "powerpc/interrupt: update common interrupt code for"
> 4. git bisect good - Xorg restarts again and again
> Output:
>
> cd6d259a14704741bf0cd1dcadb84c0de22d7f77 is the first bad commit
> commit cd6d259a14704741bf0cd1dcadb84c0de22d7f77
> Author: Christophe Leroy <christophe.le...@csgroup.eu>
> Date: Thu May 13 09:52:06 2021 +0000
>
> Revert "powerpc/64e/interrupt: always save nvgprs on interrupt"
>
> This reverts commit 4228b2c3d20e9f80b847f809c38e6cf82864fa50.
>
> :040000 040000 156542c857ad72776b69bb67b2f244afeeb7abd3
> 92ea86ed097fce16238b0c2f2b343473894e4e8e M arch
Thank you both very much for chasing this down.
I think I see the problem, it's clobbering r14 and r15 for some
interrupts. Something like this is required, I'll give it more
review and testing though.
Thanks,
Nick
---
diff --git a/arch/powerpc/kernel/exceptions-64e.S
b/arch/powerpc/kernel/exceptions-64e.S
index 7c3654b0d0f4..b91ef04f1ce2 100644
--- a/arch/powerpc/kernel/exceptions-64e.S
+++ b/arch/powerpc/kernel/exceptions-64e.S
@@ -535,6 +535,10 @@ __end_interrupts:
PROLOG_ADDITION_2REGS)
mfspr r14,SPRN_DEAR
mfspr r15,SPRN_ESR
+ std r14,_DAR(r1)
+ std r15,_DSISR(r1)
+ ld r14,PACA_EXGEN+EX_R14(r13)
+ ld r15,PACA_EXGEN+EX_R15(r13)
EXCEPTION_COMMON(0x300)
b storage_fault_common
@@ -544,6 +548,10 @@ __end_interrupts:
PROLOG_ADDITION_2REGS)
li r15,0
mr r14,r10
+ std r14,_DAR(r1)
+ std r15,_DSISR(r1)
+ ld r14,PACA_EXGEN+EX_R14(r13)
+ ld r15,PACA_EXGEN+EX_R15(r13)
EXCEPTION_COMMON(0x400)
b storage_fault_common
@@ -557,6 +565,10 @@ __end_interrupts:
PROLOG_ADDITION_2REGS)
mfspr r14,SPRN_DEAR
mfspr r15,SPRN_ESR
+ std r14,_DAR(r1)
+ std r15,_DSISR(r1)
+ ld r14,PACA_EXGEN+EX_R14(r13)
+ ld r15,PACA_EXGEN+EX_R15(r13)
EXCEPTION_COMMON(0x600)
b alignment_more /* no room, go out of line */
@@ -565,10 +577,10 @@ __end_interrupts:
NORMAL_EXCEPTION_PROLOG(0x700, BOOKE_INTERRUPT_PROGRAM,
PROLOG_ADDITION_1REG)
mfspr r14,SPRN_ESR
- EXCEPTION_COMMON(0x700)
std r14,_DSISR(r1)
- addi r3,r1,STACK_FRAME_OVERHEAD
ld r14,PACA_EXGEN+EX_R14(r13)
+ EXCEPTION_COMMON(0x700)
+ addi r3,r1,STACK_FRAME_OVERHEAD
bl program_check_exception
REST_NVGPRS(r1)
b interrupt_return
@@ -725,11 +737,11 @@ END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
* normal exception
*/
mfspr r14,SPRN_DBSR
- EXCEPTION_COMMON_CRIT(0xd00)
std r14,_DSISR(r1)
- addi r3,r1,STACK_FRAME_OVERHEAD
ld r14,PACA_EXCRIT+EX_R14(r13)
ld r15,PACA_EXCRIT+EX_R15(r13)
+ EXCEPTION_COMMON_CRIT(0xd00)
+ addi r3,r1,STACK_FRAME_OVERHEAD
bl DebugException
REST_NVGPRS(r1)
b interrupt_return
@@ -796,11 +808,11 @@ kernel_dbg_exc:
* normal exception
*/
mfspr r14,SPRN_DBSR
- EXCEPTION_COMMON_DBG(0xd08)
std r14,_DSISR(r1)
- addi r3,r1,STACK_FRAME_OVERHEAD
ld r14,PACA_EXDBG+EX_R14(r13)
ld r15,PACA_EXDBG+EX_R15(r13)
+ EXCEPTION_COMMON_DBG(0xd08)
+ addi r3,r1,STACK_FRAME_OVERHEAD
bl DebugException
REST_NVGPRS(r1)
b interrupt_return
@@ -931,11 +943,7 @@ masked_interrupt_book3e_0x2c0:
* original values stashed away in the PACA
*/
storage_fault_common:
- std r14,_DAR(r1)
- std r15,_DSISR(r1)
addi r3,r1,STACK_FRAME_OVERHEAD
- ld r14,PACA_EXGEN+EX_R14(r13)
- ld r15,PACA_EXGEN+EX_R15(r13)
bl do_page_fault
b interrupt_return
@@ -944,11 +952,7 @@ storage_fault_common:
* continues here.
*/
alignment_more:
- std r14,_DAR(r1)
- std r15,_DSISR(r1)
addi r3,r1,STACK_FRAME_OVERHEAD
- ld r14,PACA_EXGEN+EX_R14(r13)
- ld r15,PACA_EXGEN+EX_R15(r13)
bl alignment_exception
REST_NVGPRS(r1)
b interrupt_return
