2019-05-27 06:55:01 +00:00
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/* SPDX-License-Identifier: GPL-2.0-or-later */
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2005-10-28 12:53:37 +00:00
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/*
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* Copyright (C) 1996 Paul Mackerras.
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*
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* NOTE: assert(sizeof(buf) > 23 * sizeof(long))
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*/
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#include <asm/processor.h>
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#include <asm/ppc_asm.h>
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#include <asm/asm-offsets.h>
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2010-11-18 15:06:17 +00:00
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#include <asm/ptrace.h>
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2018-07-05 16:24:57 +00:00
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#include <asm/asm-compat.h>
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2005-10-28 12:53:37 +00:00
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/*
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* Grab the register values as they are now.
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2011-03-31 01:57:33 +00:00
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* This won't do a particularly good job because we really
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2005-10-28 12:53:37 +00:00
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* want our caller's caller's registers, and our caller has
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* already executed its prologue.
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* ToDo: We could reach back into the caller's save area to do
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* a better job of representing the caller's state (note that
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* that will be different for 32-bit and 64-bit, because of the
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* different ABIs, though).
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*/
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2008-12-17 10:08:55 +00:00
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_GLOBAL(ppc_save_regs)
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2022-11-27 12:49:31 +00:00
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/* This allows stack frame accessor macros and offsets to be used */
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2022-11-27 12:49:32 +00:00
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subi r3,r3,STACK_INT_FRAME_REGS
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2022-11-27 12:49:31 +00:00
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PPC_STL r0,GPR0(r3)
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2018-04-17 17:08:18 +00:00
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#ifdef CONFIG_PPC32
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2022-11-27 12:49:31 +00:00
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stmw r2,GPR2(r3)
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2018-04-17 17:08:18 +00:00
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#else
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2022-11-27 12:49:31 +00:00
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SAVE_GPRS(2, 31, r3)
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powerpc: Improve ppc_save_regs()
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>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200403131006.123243-1-npiggin@gmail.com
2020-04-03 13:10:05 +00:00
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lbz r0,PACAIRQSOFTMASK(r13)
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2022-11-27 12:49:31 +00:00
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PPC_STL r0,SOFTE(r3)
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2018-04-17 17:08:18 +00:00
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#endif
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powerpc: update ppc_save_regs to save current r1 in pt_regs
ppc_save_regs() skips one stack frame while saving the CPU register states.
Instead of saving current R1, it pulls the previous stack frame pointer.
When vmcores caused by direct panic call (such as `echo c >
/proc/sysrq-trigger`), are debugged with gdb, gdb fails to show the
backtrace correctly. On further analysis, it was found that it was because
of mismatch between r1 and NIP.
GDB uses NIP to get current function symbol and uses corresponding debug
info of that function to unwind previous frames, but due to the
mismatching r1 and NIP, the unwinding does not work, and it fails to
unwind to the 2nd frame and hence does not show the backtrace.
GDB backtrace with vmcore of kernel without this patch:
---------
(gdb) bt
#0 0xc0000000002a53e8 in crash_setup_regs (oldregs=<optimized out>,
newregs=0xc000000004f8f8d8) at ./arch/powerpc/include/asm/kexec.h:69
#1 __crash_kexec (regs=<optimized out>) at kernel/kexec_core.c:974
#2 0x0000000000000063 in ?? ()
#3 0xc000000003579320 in ?? ()
---------
Further analysis revealed that the mismatch occurred because
"ppc_save_regs" was saving the previous stack's SP instead of the current
r1. This patch fixes this by storing current r1 in the saved pt_regs.
GDB backtrace with vmcore of patched kernel:
--------
(gdb) bt
#0 0xc0000000002a53e8 in crash_setup_regs (oldregs=0x0, newregs=0xc00000000670b8d8)
at ./arch/powerpc/include/asm/kexec.h:69
#1 __crash_kexec (regs=regs@entry=0x0) at kernel/kexec_core.c:974
#2 0xc000000000168918 in panic (fmt=fmt@entry=0xc000000001654a60 "sysrq triggered crash\n")
at kernel/panic.c:358
#3 0xc000000000b735f8 in sysrq_handle_crash (key=<optimized out>) at drivers/tty/sysrq.c:155
#4 0xc000000000b742cc in __handle_sysrq (key=key@entry=99, check_mask=check_mask@entry=false)
at drivers/tty/sysrq.c:602
#5 0xc000000000b7506c in write_sysrq_trigger (file=<optimized out>, buf=<optimized out>,
count=2, ppos=<optimized out>) at drivers/tty/sysrq.c:1163
#6 0xc00000000069a7bc in pde_write (ppos=<optimized out>, count=<optimized out>,
buf=<optimized out>, file=<optimized out>, pde=0xc00000000362cb40) at fs/proc/inode.c:340
#7 proc_reg_write (file=<optimized out>, buf=<optimized out>, count=<optimized out>,
ppos=<optimized out>) at fs/proc/inode.c:352
#8 0xc0000000005b3bbc in vfs_write (file=file@entry=0xc000000006aa6b00,
buf=buf@entry=0x61f498b4f60 <error: Cannot access memory at address 0x61f498b4f60>,
count=count@entry=2, pos=pos@entry=0xc00000000670bda0) at fs/read_write.c:582
#9 0xc0000000005b4264 in ksys_write (fd=<optimized out>,
buf=0x61f498b4f60 <error: Cannot access memory at address 0x61f498b4f60>, count=2)
at fs/read_write.c:637
#10 0xc00000000002ea2c in system_call_exception (regs=0xc00000000670be80, r0=<optimized out>)
at arch/powerpc/kernel/syscall.c:171
#11 0xc00000000000c270 in system_call_vectored_common ()
at arch/powerpc/kernel/interrupt_64.S:192
--------
Nick adds:
So this now saves regs as though it was an interrupt taken in the
caller, at the instruction after the call to ppc_save_regs, whereas
previously the NIP was there, but R1 came from the caller's caller and
that mismatch is what causes gdb's dwarf unwinder to go haywire.
Signed-off-by: Aditya Gupta <adityag@linux.ibm.com>
Fixes: d16a58f8854b1 ("powerpc: Improve ppc_save_regs()")
Reivewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230615091047.90433-1-adityag@linux.ibm.com
2023-06-15 09:10:47 +00:00
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/* store current SP */
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PPC_STL r1,GPR1(r3)
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2005-10-28 12:53:37 +00:00
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/* get caller's LR */
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powerpc: update ppc_save_regs to save current r1 in pt_regs
ppc_save_regs() skips one stack frame while saving the CPU register states.
Instead of saving current R1, it pulls the previous stack frame pointer.
When vmcores caused by direct panic call (such as `echo c >
/proc/sysrq-trigger`), are debugged with gdb, gdb fails to show the
backtrace correctly. On further analysis, it was found that it was because
of mismatch between r1 and NIP.
GDB uses NIP to get current function symbol and uses corresponding debug
info of that function to unwind previous frames, but due to the
mismatching r1 and NIP, the unwinding does not work, and it fails to
unwind to the 2nd frame and hence does not show the backtrace.
GDB backtrace with vmcore of kernel without this patch:
---------
(gdb) bt
#0 0xc0000000002a53e8 in crash_setup_regs (oldregs=<optimized out>,
newregs=0xc000000004f8f8d8) at ./arch/powerpc/include/asm/kexec.h:69
#1 __crash_kexec (regs=<optimized out>) at kernel/kexec_core.c:974
#2 0x0000000000000063 in ?? ()
#3 0xc000000003579320 in ?? ()
---------
Further analysis revealed that the mismatch occurred because
"ppc_save_regs" was saving the previous stack's SP instead of the current
r1. This patch fixes this by storing current r1 in the saved pt_regs.
GDB backtrace with vmcore of patched kernel:
--------
(gdb) bt
#0 0xc0000000002a53e8 in crash_setup_regs (oldregs=0x0, newregs=0xc00000000670b8d8)
at ./arch/powerpc/include/asm/kexec.h:69
#1 __crash_kexec (regs=regs@entry=0x0) at kernel/kexec_core.c:974
#2 0xc000000000168918 in panic (fmt=fmt@entry=0xc000000001654a60 "sysrq triggered crash\n")
at kernel/panic.c:358
#3 0xc000000000b735f8 in sysrq_handle_crash (key=<optimized out>) at drivers/tty/sysrq.c:155
#4 0xc000000000b742cc in __handle_sysrq (key=key@entry=99, check_mask=check_mask@entry=false)
at drivers/tty/sysrq.c:602
#5 0xc000000000b7506c in write_sysrq_trigger (file=<optimized out>, buf=<optimized out>,
count=2, ppos=<optimized out>) at drivers/tty/sysrq.c:1163
#6 0xc00000000069a7bc in pde_write (ppos=<optimized out>, count=<optimized out>,
buf=<optimized out>, file=<optimized out>, pde=0xc00000000362cb40) at fs/proc/inode.c:340
#7 proc_reg_write (file=<optimized out>, buf=<optimized out>, count=<optimized out>,
ppos=<optimized out>) at fs/proc/inode.c:352
#8 0xc0000000005b3bbc in vfs_write (file=file@entry=0xc000000006aa6b00,
buf=buf@entry=0x61f498b4f60 <error: Cannot access memory at address 0x61f498b4f60>,
count=count@entry=2, pos=pos@entry=0xc00000000670bda0) at fs/read_write.c:582
#9 0xc0000000005b4264 in ksys_write (fd=<optimized out>,
buf=0x61f498b4f60 <error: Cannot access memory at address 0x61f498b4f60>, count=2)
at fs/read_write.c:637
#10 0xc00000000002ea2c in system_call_exception (regs=0xc00000000670be80, r0=<optimized out>)
at arch/powerpc/kernel/syscall.c:171
#11 0xc00000000000c270 in system_call_vectored_common ()
at arch/powerpc/kernel/interrupt_64.S:192
--------
Nick adds:
So this now saves regs as though it was an interrupt taken in the
caller, at the instruction after the call to ppc_save_regs, whereas
previously the NIP was there, but R1 came from the caller's caller and
that mismatch is what causes gdb's dwarf unwinder to go haywire.
Signed-off-by: Aditya Gupta <adityag@linux.ibm.com>
Fixes: d16a58f8854b1 ("powerpc: Improve ppc_save_regs()")
Reivewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230615091047.90433-1-adityag@linux.ibm.com
2023-06-15 09:10:47 +00:00
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PPC_LL r4,0(r1)
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[PATCH] powerpc: Consolidate asm compatibility macros
This patch consolidates macros used to generate assembly for
compatibility across different CPUs or configs. A new header,
asm-powerpc/asm-compat.h contains the main compatibility macros. It
uses some preprocessor magic to make the macros suitable both for use
in .S files, and in inline asm in .c files. Headers (bitops.h,
uaccess.h, atomic.h, bug.h) which had their own such compatibility
macros are changed to use asm-compat.h.
ppc_asm.h is now for use in .S files *only*, and a #error enforces
that. As such, we're a lot more careless about namespace pollution
here than in asm-compat.h.
While we're at it, this patch adds a call to the PPC405_ERR77 macro in
futex.h which should have had it already, but didn't.
Built and booted on pSeries, Maple and iSeries (ARCH=powerpc). Built
for 32-bit powermac (ARCH=powerpc) and Walnut (ARCH=ppc).
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-11-10 01:56:55 +00:00
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PPC_LL r0,LRSAVE(r4)
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2022-11-27 12:49:31 +00:00
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PPC_STL r0,_LINK(r3)
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powerpc: Improve ppc_save_regs()
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>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200403131006.123243-1-npiggin@gmail.com
2020-04-03 13:10:05 +00:00
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mflr r0
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2022-11-27 12:49:31 +00:00
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PPC_STL r0,_NIP(r3)
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2005-10-28 12:53:37 +00:00
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mfmsr r0
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2022-11-27 12:49:31 +00:00
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PPC_STL r0,_MSR(r3)
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2005-10-28 12:53:37 +00:00
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mfctr r0
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2022-11-27 12:49:31 +00:00
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PPC_STL r0,_CTR(r3)
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2005-10-28 12:53:37 +00:00
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mfxer r0
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2022-11-27 12:49:31 +00:00
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PPC_STL r0,_XER(r3)
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2005-10-28 12:53:37 +00:00
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mfcr r0
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2022-11-27 12:49:31 +00:00
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PPC_STL r0,_CCR(r3)
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2005-10-28 12:53:37 +00:00
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li r0,0
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2022-11-27 12:49:31 +00:00
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PPC_STL r0,_TRAP(r3)
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PPC_STL r0,ORIG_GPR3(r3)
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2005-10-28 12:53:37 +00:00
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