From: Nicholas Piggin <npiggin@gmail.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: Nicholas Piggin <npiggin@gmail.com>
Subject: [PATCH] powerpc: improve ppc_save_regs
Date: Fri, 3 Apr 2020 23:10:05 +1000 [thread overview]
Message-ID: <20200403131006.123243-1-npiggin@gmail.com> (raw)
Make ppc_save_regs a bit more useful:
- Set NIP to our caller rather rather than the caller's caller (which is
what we save to LR in the stack frame).
- Set SOFTE to the current irq soft-mask state rather than
uninitialised.
- Zero CFAR rather than leave it uninitialised.
In qemu, injecting a nmi to an idle CPU gives a nicer stack trace (note
NIP, IRQMASK, CFAR).
Oops: System Reset, sig: 6 [#1]
LE PAGE_SIZE=64K MMU=Hash PREEMPT SMP NR_CPUS=2048 NUMA PowerNV
Modules linked in:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.6.0-rc2-00429-ga76e38fd80bf #1277
NIP: c0000000000b6e5c LR: c0000000000b6e5c CTR: c000000000b06270
REGS: c00000000173fb08 TRAP: 0100 Not tainted
MSR: 9000000000001033 <SF,HV,ME,IR,DR,RI,LE> CR: 28000224 XER: 00000000
CFAR: c0000000016a2128 IRQMASK: c00000000173fc80
GPR00: c0000000000b6e5c c00000000173fc80 c000000001743400 c00000000173fb08
GPR04: 0000000000000000 0000000000000000 0000000000000008 0000000000000001
GPR08: 00000001fea80000 0000000000000000 0000000000000000 ffffffffffffffff
GPR12: c000000000b06270 c000000001930000 00000000300026c0 0000000000000000
GPR16: 0000000000000000 0000000000000000 0000000000000003 c0000000016a2128
GPR20: c0000001ffc97148 0000000000000001 c000000000f289a8 0000000000080000
GPR24: c0000000016e1480 000000011dc870ba 0000000000000000 0000000000000003
GPR28: c0000000016a2128 c0000001ffc97148 c0000000016a2260 0000000000000003
NIP [c0000000000b6e5c] power9_idle_type+0x5c/0x70
LR [c0000000000b6e5c] power9_idle_type+0x5c/0x70
Call Trace:
[c00000000173fc80] [c0000000000b6e5c] power9_idle_type+0x5c/0x70 (unreliable)
[c00000000173fcb0] [c000000000b062b0] stop_loop+0x40/0x60
[c00000000173fce0] [c000000000b022d8] cpuidle_enter_state+0xa8/0x660
[c00000000173fd60] [c000000000b0292c] cpuidle_enter+0x4c/0x70
[c00000000173fda0] [c00000000017624c] call_cpuidle+0x4c/0x90
[c00000000173fdc0] [c000000000176768] do_idle+0x338/0x460
[c00000000173fe60] [c000000000176b3c] cpu_startup_entry+0x3c/0x40
[c00000000173fe90] [c0000000000126b4] rest_init+0x124/0x140
[c00000000173fed0] [c0000000010948d4] start_kernel+0x938/0x988
[c00000000173ff90] [c00000000000cdcc] start_here_common+0x1c/0x20
Oops: System Reset, sig: 6 [#1]
LE PAGE_SIZE=64K MMU=Hash PREEMPT SMP NR_CPUS=2048 NUMA PowerNV
Modules linked in:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.6.0-rc2-00430-gddce91b8712f #1278
NIP: c00000000001d150 LR: c0000000000b6e5c CTR: c000000000b06270
REGS: c00000000173fb08 TRAP: 0100 Not tainted
MSR: 9000000000001033 <SF,HV,ME,IR,DR,RI,LE> CR: 28000224 XER: 00000000
CFAR: 0000000000000000 IRQMASK: 1
GPR00: c0000000000b6e5c c00000000173fc80 c000000001743400 c00000000173fb08
GPR04: 0000000000000000 0000000000000000 0000000000000008 0000000000000001
GPR08: 00000001fea80000 0000000000000000 0000000000000000 ffffffffffffffff
GPR12: c000000000b06270 c000000001930000 00000000300026c0 0000000000000000
GPR16: 0000000000000000 0000000000000000 0000000000000003 c0000000016a2128
GPR20: c0000001ffc97148 0000000000000001 c000000000f289a8 0000000000080000
GPR24: c0000000016e1480 00000000b68db8ce 0000000000000000 0000000000000003
GPR28: c0000000016a2128 c0000001ffc97148 c0000000016a2260 0000000000000003
NIP [c00000000001d150] replay_system_reset+0x30/0xa0
LR [c0000000000b6e5c] power9_idle_type+0x5c/0x70
Call Trace:
[c00000000173fc80] [c0000000000b6e5c] power9_idle_type+0x5c/0x70 (unreliable)
[c00000000173fcb0] [c000000000b062b0] stop_loop+0x40/0x60
[c00000000173fce0] [c000000000b022d8] cpuidle_enter_state+0xa8/0x660
[c00000000173fd60] [c000000000b0292c] cpuidle_enter+0x4c/0x70
[c00000000173fda0] [c00000000017624c] call_cpuidle+0x4c/0x90
[c00000000173fdc0] [c000000000176768] do_idle+0x338/0x460
[c00000000173fe60] [c000000000176b38] cpu_startup_entry+0x38/0x40
[c00000000173fe90] [c0000000000126b4] rest_init+0x124/0x140
[c00000000173fed0] [c0000000010948d4] start_kernel+0x938/0x988
[c00000000173ff90] [c00000000000cdcc] start_here_common+0x1c/0x20
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
This becomes more important after implementing irq replay in C.
arch/powerpc/kernel/ppc_save_regs.S | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/kernel/ppc_save_regs.S b/arch/powerpc/kernel/ppc_save_regs.S
index f3bd0bbf2ae8..2d4d21bb46a9 100644
--- a/arch/powerpc/kernel/ppc_save_regs.S
+++ b/arch/powerpc/kernel/ppc_save_regs.S
@@ -55,14 +55,17 @@ _GLOBAL(ppc_save_regs)
PPC_STL r29,29*SZL(r3)
PPC_STL r30,30*SZL(r3)
PPC_STL r31,31*SZL(r3)
+ lbz r0,PACAIRQSOFTMASK(r13)
+ PPC_STL r0,SOFTE-STACK_FRAME_OVERHEAD(r3)
#endif
/* go up one stack frame for SP */
PPC_LL r4,0(r1)
PPC_STL r4,1*SZL(r3)
/* get caller's LR */
PPC_LL r0,LRSAVE(r4)
- PPC_STL r0,_NIP-STACK_FRAME_OVERHEAD(r3)
PPC_STL r0,_LINK-STACK_FRAME_OVERHEAD(r3)
+ mflr r0
+ PPC_STL r0,_NIP-STACK_FRAME_OVERHEAD(r3)
mfmsr r0
PPC_STL r0,_MSR-STACK_FRAME_OVERHEAD(r3)
mfctr r0
@@ -73,4 +76,5 @@ _GLOBAL(ppc_save_regs)
PPC_STL r0,_CCR-STACK_FRAME_OVERHEAD(r3)
li r0,0
PPC_STL r0,_TRAP-STACK_FRAME_OVERHEAD(r3)
+ PPC_STL r0,ORIG_GPR3-STACK_FRAME_OVERHEAD(r3)
blr
--
2.23.0
next reply other threads:[~2020-04-03 13:14 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-03 13:10 Nicholas Piggin [this message]
2020-04-06 13:06 ` [PATCH] powerpc: improve ppc_save_regs Michael Ellerman
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