* [PATCH v3 00/15] powerpc/64: machine check and system reset fixes
@ 2020-04-07 5:16 Nicholas Piggin
2020-04-07 5:16 ` [PATCH v3 01/15] powerpc/64s/exception: Fix machine check no-loss idle wakeup Nicholas Piggin
` (14 more replies)
0 siblings, 15 replies; 27+ messages in thread
From: Nicholas Piggin @ 2020-04-07 5:16 UTC (permalink / raw)
To: linuxppc-dev; +Cc: Mahesh Salgaonkar, Ganesh Goudar, Nicholas Piggin
There's a bunch of problems we hit bringing up fwnmi sreset and testing
with mce injection on QEMU. Mostly pseries issues.
This series of fixes applies on top of next-test, the machine
check reconcile patch won't apply cleanly to previous kernels but
it might want to be backported. We can do that after upstreaming.
This doesn't solve all known problems yet, but fwnmi machine check
and system reset injection in QEMU is significantly better. There
will be more to come but these should be ready for review now.
Thanks,
Nick
v3:
- Addressed comments and fixed compile bugs.
- Didn't convert to pr_err because it's an existing printk that was
moved. A cleanup to convert printks could go afterward.
v2:
- Added a couple more fixes
- Review comments and tags
- Re-tested with some fixes to my qemu machine check injection patches
Nicholas Piggin (15):
powerpc/64s/exception: Fix machine check no-loss idle wakeup
powerpc/64s/exceptions: Fix in_mce accounting in unrecoverable path
powerpc/64s/exceptions: Change irq reconcile for NMIs from reusing
_DAR to RESULT
powerpc/64s/exceptions: machine check reconcile irq state
powerpc/pseries/ras: avoid calling rtas_token in NMI paths
powerpc/pseries/ras: FWNMI_VALID off by one
powerpc/pseries/ras: fwnmi avoid modifying r3 in error case
powerpc/pseries/ras: fwnmi sreset should not interlock
powerpc/pseries: limit machine check stack to 4GB
powerpc/pseries: machine check use rtas_call_unlocked with args on
stack
powerpc/64s: machine check interrupt update NMI accounting
powerpc: ftrace_enabled helper
powerpc/64s: machine check do not trace real-mode handler
powerpc/64s: system reset do not trace
powerpc: make unrecoverable NMIs die instead of panic
arch/powerpc/include/asm/firmware.h | 1 +
arch/powerpc/include/asm/ftrace.h | 14 ++++++
arch/powerpc/kernel/exceptions-64s.S | 47 +++++++++++++++-----
arch/powerpc/kernel/mce.c | 16 ++++++-
arch/powerpc/kernel/process.c | 2 +-
arch/powerpc/kernel/setup_64.c | 15 +++++--
arch/powerpc/kernel/traps.c | 24 ++++-------
arch/powerpc/platforms/pseries/ras.c | 60 +++++++++++++++++++-------
arch/powerpc/platforms/pseries/setup.c | 14 ++++--
9 files changed, 142 insertions(+), 51 deletions(-)
--
2.23.0
^ permalink raw reply [flat|nested] 27+ messages in thread
* [PATCH v3 01/15] powerpc/64s/exception: Fix machine check no-loss idle wakeup
2020-04-07 5:16 [PATCH v3 00/15] powerpc/64: machine check and system reset fixes Nicholas Piggin
@ 2020-04-07 5:16 ` Nicholas Piggin
2020-04-07 5:16 ` [PATCH v3 02/15] powerpc/64s/exceptions: Fix in_mce accounting in unrecoverable path Nicholas Piggin
` (13 subsequent siblings)
14 siblings, 0 replies; 27+ messages in thread
From: Nicholas Piggin @ 2020-04-07 5:16 UTC (permalink / raw)
To: linuxppc-dev; +Cc: Mahesh Salgaonkar, Ganesh Goudar, Nicholas Piggin
The architecture allows for machine check exceptions to cause idle
wakeups which resume at the 0x200 address which has to return via
the idle wakeup code, but the early machine check handler is run
first.
The case of a no state-loss sleep is broken because the early
handler uses non-volatile register r1 , which is needed for the wakeup
protocol, but it is not restored.
Fix this by loading r1 from the MCE exception frame before returning
to the idle wakeup code. Also update the comment which has become
stale since the idle rewrite in C.
Fixes: 10d91611f426d ("powerpc/64s: Reimplement book3s idle code in C")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
arch/powerpc/kernel/exceptions-64s.S | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index 728ccb0f560c..bbf3109c5cba 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -1224,17 +1224,19 @@ EXC_COMMON_BEGIN(machine_check_idle_common)
bl machine_check_queue_event
/*
- * We have not used any non-volatile GPRs here, and as a rule
- * most exception code including machine check does not.
- * Therefore PACA_NAPSTATELOST does not need to be set. Idle
- * wakeup will restore volatile registers.
+ * GPR-loss wakeups are relatively straightforward, because the
+ * idle sleep code has saved all non-volatile registers on its
+ * own stack, and r1 in PACAR1.
*
- * Load the original SRR1 into r3 for pnv_powersave_wakeup_mce.
+ * For no-loss wakeups the r1 and lr registers used by the
+ * early machine check handler have to be restored first. r2 is
+ * the kernel TOC, so no need to restore it.
*
* Then decrement MCE nesting after finishing with the stack.
*/
ld r3,_MSR(r1)
ld r4,_LINK(r1)
+ ld r1,GPR1(r1)
lhz r11,PACA_IN_MCE(r13)
subi r11,r11,1
@@ -1243,7 +1245,7 @@ EXC_COMMON_BEGIN(machine_check_idle_common)
mtlr r4
rlwinm r10,r3,47-31,30,31
cmpwi cr1,r10,2
- bltlr cr1 /* no state loss, return to idle caller */
+ bltlr cr1 /* no state loss, return to idle caller with r3=SRR1 */
b idle_return_gpr_loss
#endif
--
2.23.0
^ permalink raw reply related [flat|nested] 27+ messages in thread
* [PATCH v3 02/15] powerpc/64s/exceptions: Fix in_mce accounting in unrecoverable path
2020-04-07 5:16 [PATCH v3 00/15] powerpc/64: machine check and system reset fixes Nicholas Piggin
2020-04-07 5:16 ` [PATCH v3 01/15] powerpc/64s/exception: Fix machine check no-loss idle wakeup Nicholas Piggin
@ 2020-04-07 5:16 ` Nicholas Piggin
2020-04-07 5:16 ` [PATCH v3 03/15] powerpc/64s/exceptions: Change irq reconcile for NMIs from reusing _DAR to RESULT Nicholas Piggin
` (12 subsequent siblings)
14 siblings, 0 replies; 27+ messages in thread
From: Nicholas Piggin @ 2020-04-07 5:16 UTC (permalink / raw)
To: linuxppc-dev
Cc: Mahesh Salgaonkar, Ganesh Goudar, Mahesh Salgaonkar, Nicholas Piggin
Acked-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
arch/powerpc/kernel/exceptions-64s.S | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index bbf3109c5cba..3322000316ab 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -1267,6 +1267,10 @@ END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)
andc r10,r10,r3
mtmsrd r10
+ lhz r12,PACA_IN_MCE(r13)
+ subi r12,r12,1
+ sth r12,PACA_IN_MCE(r13)
+
/* Invoke machine_check_exception to print MCE event and panic. */
addi r3,r1,STACK_FRAME_OVERHEAD
bl machine_check_exception
--
2.23.0
^ permalink raw reply related [flat|nested] 27+ messages in thread
* [PATCH v3 03/15] powerpc/64s/exceptions: Change irq reconcile for NMIs from reusing _DAR to RESULT
2020-04-07 5:16 [PATCH v3 00/15] powerpc/64: machine check and system reset fixes Nicholas Piggin
2020-04-07 5:16 ` [PATCH v3 01/15] powerpc/64s/exception: Fix machine check no-loss idle wakeup Nicholas Piggin
2020-04-07 5:16 ` [PATCH v3 02/15] powerpc/64s/exceptions: Fix in_mce accounting in unrecoverable path Nicholas Piggin
@ 2020-04-07 5:16 ` Nicholas Piggin
2020-04-07 5:16 ` [PATCH v3 04/15] powerpc/64s/exceptions: machine check reconcile irq state Nicholas Piggin
` (11 subsequent siblings)
14 siblings, 0 replies; 27+ messages in thread
From: Nicholas Piggin @ 2020-04-07 5:16 UTC (permalink / raw)
To: linuxppc-dev; +Cc: Mahesh Salgaonkar, Ganesh Goudar, Nicholas Piggin
A spare interrupt stack slot is needed to save irq state when
reconciling NMIs (sreset and decrementer soft-nmi). _DAR is used
for this, but we want to reconcile machine checks as well, which
do use _DAR. Switch to using RESULT instead, as it's used by
system calls.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
arch/powerpc/kernel/exceptions-64s.S | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index 3322000316ab..a42b73efb1a9 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -939,13 +939,13 @@ EXC_COMMON_BEGIN(system_reset_common)
* the right thing. We do not want to reconcile because that goes
* through irq tracing which we don't want in NMI.
*
- * Save PACAIRQHAPPENED to _DAR (otherwise unused), and set HARD_DIS
+ * Save PACAIRQHAPPENED to RESULT (otherwise unused), and set HARD_DIS
* as we are running with MSR[EE]=0.
*/
li r10,IRQS_ALL_DISABLED
stb r10,PACAIRQSOFTMASK(r13)
lbz r10,PACAIRQHAPPENED(r13)
- std r10,_DAR(r1)
+ std r10,RESULT(r1)
ori r10,r10,PACA_IRQ_HARD_DIS
stb r10,PACAIRQHAPPENED(r13)
@@ -966,7 +966,7 @@ EXC_COMMON_BEGIN(system_reset_common)
/*
* Restore soft mask settings.
*/
- ld r10,_DAR(r1)
+ ld r10,RESULT(r1)
stb r10,PACAIRQHAPPENED(r13)
ld r10,SOFTE(r1)
stb r10,PACAIRQSOFTMASK(r13)
@@ -2743,7 +2743,7 @@ EXC_COMMON_BEGIN(soft_nmi_common)
li r10,IRQS_ALL_DISABLED
stb r10,PACAIRQSOFTMASK(r13)
lbz r10,PACAIRQHAPPENED(r13)
- std r10,_DAR(r1)
+ std r10,RESULT(r1)
ori r10,r10,PACA_IRQ_HARD_DIS
stb r10,PACAIRQHAPPENED(r13)
@@ -2757,7 +2757,7 @@ EXC_COMMON_BEGIN(soft_nmi_common)
/*
* Restore soft mask settings.
*/
- ld r10,_DAR(r1)
+ ld r10,RESULT(r1)
stb r10,PACAIRQHAPPENED(r13)
ld r10,SOFTE(r1)
stb r10,PACAIRQSOFTMASK(r13)
--
2.23.0
^ permalink raw reply related [flat|nested] 27+ messages in thread
* [PATCH v3 04/15] powerpc/64s/exceptions: machine check reconcile irq state
2020-04-07 5:16 [PATCH v3 00/15] powerpc/64: machine check and system reset fixes Nicholas Piggin
` (2 preceding siblings ...)
2020-04-07 5:16 ` [PATCH v3 03/15] powerpc/64s/exceptions: Change irq reconcile for NMIs from reusing _DAR to RESULT Nicholas Piggin
@ 2020-04-07 5:16 ` Nicholas Piggin
2020-04-07 5:16 ` [PATCH v3 05/15] powerpc/pseries/ras: avoid calling rtas_token in NMI paths Nicholas Piggin
` (10 subsequent siblings)
14 siblings, 0 replies; 27+ messages in thread
From: Nicholas Piggin @ 2020-04-07 5:16 UTC (permalink / raw)
To: linuxppc-dev; +Cc: Mahesh Salgaonkar, Ganesh Goudar, Nicholas Piggin
pseries fwnmi machine check code pops the soft-irq checks in rtas_call
(after the previous patch to remove rtas_token from this call path).
Rather than play whack a mole with these and forever having fragile
code, it seems better to have the early machine check handler perform
the same kind of reconcile as the other NMI interrupts.
WARNING: CPU: 0 PID: 493 at arch/powerpc/kernel/irq.c:343
CPU: 0 PID: 493 Comm: a Tainted: G W
NIP: c00000000001ed2c LR: c000000000042c40 CTR: 0000000000000000
REGS: c0000001fffd38b0 TRAP: 0700 Tainted: G W
MSR: 8000000000021003 <SF,ME,RI,LE> CR: 28000488 XER: 00000000
CFAR: c00000000001ec90 IRQMASK: 0
GPR00: c000000000043820 c0000001fffd3b40 c0000000012ba300 0000000000000000
GPR04: 0000000048000488 0000000000000000 0000000000000000 00000000deadbeef
GPR08: 0000000000000080 0000000000000000 0000000000000000 0000000000001001
GPR12: 0000000000000000 c0000000014a0000 0000000000000000 0000000000000000
GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
GPR20: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
GPR24: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
GPR28: 0000000000000000 0000000000000001 c000000001360810 0000000000000000
NIP [c00000000001ed2c] arch_local_irq_restore.part.0+0xac/0x100
LR [c000000000042c40] unlock_rtas+0x30/0x90
Call Trace:
[c0000001fffd3b40] [c000000001360810] 0xc000000001360810 (unreliable)
[c0000001fffd3b60] [c000000000043820] rtas_call+0x1c0/0x280
[c0000001fffd3bb0] [c0000000000dc328] fwnmi_release_errinfo+0x38/0x70
[c0000001fffd3c10] [c0000000000dcd8c] pseries_machine_check_realmode+0x1dc/0x540
[c0000001fffd3cd0] [c00000000003fe04] machine_check_early+0x54/0x70
[c0000001fffd3d00] [c000000000008384] machine_check_early_common+0x134/0x1f0
--- interrupt: 200 at 0x13f1307c8
LR = 0x7fff888b8528
Instruction dump:
60000000 7d2000a6 71298000 41820068 39200002 7d210164 4bffff9c 60000000
60000000 7d2000a6 71298000 4c820020 <0fe00000> 4e800020 60000000 60000000
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
arch/powerpc/kernel/exceptions-64s.S | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index a42b73efb1a9..072772803b7c 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -1116,11 +1116,30 @@ END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)
li r10,MSR_RI
mtmsrd r10,1
+ /*
+ * Set IRQS_ALL_DISABLED and save PACAIRQHAPPENED (see
+ * system_reset_common)
+ */
+ li r10,IRQS_ALL_DISABLED
+ stb r10,PACAIRQSOFTMASK(r13)
+ lbz r10,PACAIRQHAPPENED(r13)
+ std r10,RESULT(r1)
+ ori r10,r10,PACA_IRQ_HARD_DIS
+ stb r10,PACAIRQHAPPENED(r13)
+
addi r3,r1,STACK_FRAME_OVERHEAD
bl machine_check_early
std r3,RESULT(r1) /* Save result */
ld r12,_MSR(r1)
+ /*
+ * Restore soft mask settings.
+ */
+ ld r10,RESULT(r1)
+ stb r10,PACAIRQHAPPENED(r13)
+ ld r10,SOFTE(r1)
+ stb r10,PACAIRQSOFTMASK(r13)
+
#ifdef CONFIG_PPC_P7_NAP
/*
* Check if thread was in power saving mode. We come here when any
--
2.23.0
^ permalink raw reply related [flat|nested] 27+ messages in thread
* [PATCH v3 05/15] powerpc/pseries/ras: avoid calling rtas_token in NMI paths
2020-04-07 5:16 [PATCH v3 00/15] powerpc/64: machine check and system reset fixes Nicholas Piggin
` (3 preceding siblings ...)
2020-04-07 5:16 ` [PATCH v3 04/15] powerpc/64s/exceptions: machine check reconcile irq state Nicholas Piggin
@ 2020-04-07 5:16 ` Nicholas Piggin
2020-04-07 5:42 ` Christophe Leroy
2020-04-07 5:16 ` [PATCH v3 06/15] powerpc/pseries/ras: FWNMI_VALID off by one Nicholas Piggin
` (9 subsequent siblings)
14 siblings, 1 reply; 27+ messages in thread
From: Nicholas Piggin @ 2020-04-07 5:16 UTC (permalink / raw)
To: linuxppc-dev
Cc: Mahesh Salgaonkar, Ganesh Goudar, Mahesh Salgaonkar, Nicholas Piggin
In the interest of reducing code and possible failures in the
machine check and system reset paths, grab the "ibm,nmi-interlock"
token at init time.
Reviewed-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
arch/powerpc/include/asm/firmware.h | 1 +
arch/powerpc/platforms/pseries/ras.c | 2 +-
arch/powerpc/platforms/pseries/setup.c | 14 ++++++++++----
3 files changed, 12 insertions(+), 5 deletions(-)
diff --git a/arch/powerpc/include/asm/firmware.h b/arch/powerpc/include/asm/firmware.h
index ca33f4ef6cb4..6003c2e533a0 100644
--- a/arch/powerpc/include/asm/firmware.h
+++ b/arch/powerpc/include/asm/firmware.h
@@ -128,6 +128,7 @@ extern void machine_check_fwnmi(void);
/* This is true if we are using the firmware NMI handler (typically LPAR) */
extern int fwnmi_active;
+extern int ibm_nmi_interlock_token;
extern unsigned int __start___fw_ftr_fixup, __stop___fw_ftr_fixup;
diff --git a/arch/powerpc/platforms/pseries/ras.c b/arch/powerpc/platforms/pseries/ras.c
index aa6208c8d4f0..972b95ebc867 100644
--- a/arch/powerpc/platforms/pseries/ras.c
+++ b/arch/powerpc/platforms/pseries/ras.c
@@ -458,7 +458,7 @@ static struct rtas_error_log *fwnmi_get_errinfo(struct pt_regs *regs)
*/
static void fwnmi_release_errinfo(void)
{
- int ret = rtas_call(rtas_token("ibm,nmi-interlock"), 0, 1, NULL);
+ int ret = rtas_call(ibm_nmi_interlock_token, 0, 1, NULL);
if (ret != 0)
printk(KERN_ERR "FWNMI: nmi-interlock failed: %d\n", ret);
}
diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index 0c8421dd01ab..dd234095ae4f 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -83,6 +83,7 @@ unsigned long CMO_PageSize = (ASM_CONST(1) << IOMMU_PAGE_SHIFT_4K);
EXPORT_SYMBOL(CMO_PageSize);
int fwnmi_active; /* TRUE if an FWNMI handler is present */
+int ibm_nmi_interlock_token;
static void pSeries_show_cpuinfo(struct seq_file *m)
{
@@ -113,9 +114,14 @@ static void __init fwnmi_init(void)
struct slb_entry *slb_ptr;
size_t size;
#endif
+ int ibm_nmi_register_token;
- int ibm_nmi_register = rtas_token("ibm,nmi-register");
- if (ibm_nmi_register == RTAS_UNKNOWN_SERVICE)
+ ibm_nmi_register_token = rtas_token("ibm,nmi-register");
+ if (ibm_nmi_register_token == RTAS_UNKNOWN_SERVICE)
+ return;
+
+ ibm_nmi_interlock_token = rtas_token("ibm,nmi-interlock");
+ if (WARN_ON(ibm_nmi_interlock_token == RTAS_UNKNOWN_SERVICE))
return;
/* If the kernel's not linked at zero we point the firmware at low
@@ -123,8 +129,8 @@ static void __init fwnmi_init(void)
system_reset_addr = __pa(system_reset_fwnmi) - PHYSICAL_START;
machine_check_addr = __pa(machine_check_fwnmi) - PHYSICAL_START;
- if (0 == rtas_call(ibm_nmi_register, 2, 1, NULL, system_reset_addr,
- machine_check_addr))
+ if (0 == rtas_call(ibm_nmi_register_token, 2, 1, NULL,
+ system_reset_addr, machine_check_addr))
fwnmi_active = 1;
/*
--
2.23.0
^ permalink raw reply related [flat|nested] 27+ messages in thread
* [PATCH v3 06/15] powerpc/pseries/ras: FWNMI_VALID off by one
2020-04-07 5:16 [PATCH v3 00/15] powerpc/64: machine check and system reset fixes Nicholas Piggin
` (4 preceding siblings ...)
2020-04-07 5:16 ` [PATCH v3 05/15] powerpc/pseries/ras: avoid calling rtas_token in NMI paths Nicholas Piggin
@ 2020-04-07 5:16 ` Nicholas Piggin
2020-04-07 5:16 ` [PATCH v3 07/15] powerpc/pseries/ras: fwnmi avoid modifying r3 in error case Nicholas Piggin
` (8 subsequent siblings)
14 siblings, 0 replies; 27+ messages in thread
From: Nicholas Piggin @ 2020-04-07 5:16 UTC (permalink / raw)
To: linuxppc-dev
Cc: Mahesh Salgaonkar, Ganesh Goudar, Mahesh Salgaonkar, Nicholas Piggin
This was discovered developing qemu fwnmi sreset support. This
off-by-one bug means the last 16 bytes of the rtas area can not
be used for a 16 byte save area.
It's not a serious bug, and QEMU implementation has to retain a
workaround for old kernels, but it's good to tighten it.
Acked-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
arch/powerpc/platforms/pseries/ras.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/platforms/pseries/ras.c b/arch/powerpc/platforms/pseries/ras.c
index 972b95ebc867..ed43c2e4d4ee 100644
--- a/arch/powerpc/platforms/pseries/ras.c
+++ b/arch/powerpc/platforms/pseries/ras.c
@@ -395,10 +395,11 @@ static irqreturn_t ras_error_interrupt(int irq, void *dev_id)
/*
* Some versions of FWNMI place the buffer inside the 4kB page starting at
* 0x7000. Other versions place it inside the rtas buffer. We check both.
+ * Minimum size of the buffer is 16 bytes.
*/
#define VALID_FWNMI_BUFFER(A) \
- ((((A) >= 0x7000) && ((A) < 0x7ff0)) || \
- (((A) >= rtas.base) && ((A) < (rtas.base + rtas.size - 16))))
+ ((((A) >= 0x7000) && ((A) <= 0x8000 - 16)) || \
+ (((A) >= rtas.base) && ((A) <= (rtas.base + rtas.size - 16))))
static inline struct rtas_error_log *fwnmi_get_errlog(void)
{
--
2.23.0
^ permalink raw reply related [flat|nested] 27+ messages in thread
* [PATCH v3 07/15] powerpc/pseries/ras: fwnmi avoid modifying r3 in error case
2020-04-07 5:16 [PATCH v3 00/15] powerpc/64: machine check and system reset fixes Nicholas Piggin
` (5 preceding siblings ...)
2020-04-07 5:16 ` [PATCH v3 06/15] powerpc/pseries/ras: FWNMI_VALID off by one Nicholas Piggin
@ 2020-04-07 5:16 ` Nicholas Piggin
2020-04-07 5:16 ` [PATCH v3 08/15] powerpc/pseries/ras: fwnmi sreset should not interlock Nicholas Piggin
` (7 subsequent siblings)
14 siblings, 0 replies; 27+ messages in thread
From: Nicholas Piggin @ 2020-04-07 5:16 UTC (permalink / raw)
To: linuxppc-dev; +Cc: Mahesh Salgaonkar, Ganesh Goudar, Nicholas Piggin
If there is some error with the fwnmi save area, r3 has already been
modified which doesn't help with debugging.
Only update r3 when to restore the saved value.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
arch/powerpc/platforms/pseries/ras.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/platforms/pseries/ras.c b/arch/powerpc/platforms/pseries/ras.c
index ed43c2e4d4ee..2c60e2be1bc5 100644
--- a/arch/powerpc/platforms/pseries/ras.c
+++ b/arch/powerpc/platforms/pseries/ras.c
@@ -423,18 +423,19 @@ static inline struct rtas_error_log *fwnmi_get_errlog(void)
*/
static struct rtas_error_log *fwnmi_get_errinfo(struct pt_regs *regs)
{
+ unsigned long savep_ra;
unsigned long *savep;
struct rtas_error_log *h;
/* Mask top two bits */
- regs->gpr[3] &= ~(0x3UL << 62);
+ savep_ra = regs->gpr[3] & ~(0x3UL << 62);
- if (!VALID_FWNMI_BUFFER(regs->gpr[3])) {
+ if (!VALID_FWNMI_BUFFER(savep_ra)) {
printk(KERN_ERR "FWNMI: corrupt r3 0x%016lx\n", regs->gpr[3]);
return NULL;
}
- savep = __va(regs->gpr[3]);
+ savep = __va(savep_ra);
regs->gpr[3] = be64_to_cpu(savep[0]); /* restore original r3 */
h = (struct rtas_error_log *)&savep[1];
--
2.23.0
^ permalink raw reply related [flat|nested] 27+ messages in thread
* [PATCH v3 08/15] powerpc/pseries/ras: fwnmi sreset should not interlock
2020-04-07 5:16 [PATCH v3 00/15] powerpc/64: machine check and system reset fixes Nicholas Piggin
` (6 preceding siblings ...)
2020-04-07 5:16 ` [PATCH v3 07/15] powerpc/pseries/ras: fwnmi avoid modifying r3 in error case Nicholas Piggin
@ 2020-04-07 5:16 ` Nicholas Piggin
2020-04-07 5:41 ` Christophe Leroy
2020-04-07 5:16 ` [PATCH v3 09/15] powerpc/pseries: limit machine check stack to 4GB Nicholas Piggin
` (6 subsequent siblings)
14 siblings, 1 reply; 27+ messages in thread
From: Nicholas Piggin @ 2020-04-07 5:16 UTC (permalink / raw)
To: linuxppc-dev; +Cc: Mahesh Salgaonkar, Ganesh Goudar, Nicholas Piggin
PAPR does not specify that fwnmi sreset should be interlocked, and
PowerVM (and therefore now QEMU) do not require it.
These "ibm,nmi-interlock" calls are ignored by firmware, but there
is a possibility that the sreset could have interrupted a machine
check and release the machine check's interlock too early, corrupting
it if another machine check came in.
This is an extremely rare case, but it should be fixed for clarity
and reducing the code executed in the sreset path. Firmware also
does not provide error information for the sreset case to look at, so
remove that comment.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
arch/powerpc/platforms/pseries/ras.c | 46 +++++++++++++++++++---------
1 file changed, 32 insertions(+), 14 deletions(-)
diff --git a/arch/powerpc/platforms/pseries/ras.c b/arch/powerpc/platforms/pseries/ras.c
index 2c60e2be1bc5..d65bc38bcb8f 100644
--- a/arch/powerpc/platforms/pseries/ras.c
+++ b/arch/powerpc/platforms/pseries/ras.c
@@ -406,6 +406,20 @@ static inline struct rtas_error_log *fwnmi_get_errlog(void)
return (struct rtas_error_log *)local_paca->mce_data_buf;
}
+static unsigned long *fwnmi_get_savep(struct pt_regs *regs)
+{
+ unsigned long savep_ra;
+
+ /* Mask top two bits */
+ savep_ra = regs->gpr[3] & ~(0x3UL << 62);
+ if (!VALID_FWNMI_BUFFER(savep_ra)) {
+ printk(KERN_ERR "FWNMI: corrupt r3 0x%016lx\n", regs->gpr[3]);
+ return NULL;
+ }
+
+ return __va(savep_ra);
+}
+
/*
* Get the error information for errors coming through the
* FWNMI vectors. The pt_regs' r3 will be updated to reflect
@@ -423,20 +437,14 @@ static inline struct rtas_error_log *fwnmi_get_errlog(void)
*/
static struct rtas_error_log *fwnmi_get_errinfo(struct pt_regs *regs)
{
- unsigned long savep_ra;
unsigned long *savep;
struct rtas_error_log *h;
- /* Mask top two bits */
- savep_ra = regs->gpr[3] & ~(0x3UL << 62);
-
- if (!VALID_FWNMI_BUFFER(savep_ra)) {
- printk(KERN_ERR "FWNMI: corrupt r3 0x%016lx\n", regs->gpr[3]);
+ savep = fwnmi_get_savep(regs);
+ if (!savep)
return NULL;
- }
- savep = __va(savep_ra);
- regs->gpr[3] = be64_to_cpu(savep[0]); /* restore original r3 */
+ regs->gpr[3] = be64_to_cpu(savep[0]); /* restore original r3 */
h = (struct rtas_error_log *)&savep[1];
/* Use the per cpu buffer from paca to store rtas error log */
@@ -483,11 +491,21 @@ int pSeries_system_reset_exception(struct pt_regs *regs)
#endif
if (fwnmi_active) {
- struct rtas_error_log *errhdr = fwnmi_get_errinfo(regs);
- if (errhdr) {
- /* XXX Should look at FWNMI information */
- }
- fwnmi_release_errinfo();
+ unsigned long *savep;
+
+ /*
+ * Firmware (PowerVM and KVM) saves r3 to a save area like
+ * machine check, which is not exactly what PAPR (2.9)
+ * suggests but there is no way to detect otherwise, so this
+ * is the interface now.
+ *
+ * System resets do not save any error log or require an
+ * "ibm,nmi-interlock" rtas call to release.
+ */
+
+ savep = fwnmi_get_savep(regs);
+ if (savep)
+ regs->gpr[3] = be64_to_cpu(savep[0]); /* restore original r3 */
}
if (smp_handle_nmi_ipi(regs))
--
2.23.0
^ permalink raw reply related [flat|nested] 27+ messages in thread
* [PATCH v3 09/15] powerpc/pseries: limit machine check stack to 4GB
2020-04-07 5:16 [PATCH v3 00/15] powerpc/64: machine check and system reset fixes Nicholas Piggin
` (7 preceding siblings ...)
2020-04-07 5:16 ` [PATCH v3 08/15] powerpc/pseries/ras: fwnmi sreset should not interlock Nicholas Piggin
@ 2020-04-07 5:16 ` Nicholas Piggin
2020-04-07 5:38 ` Christophe Leroy
2020-04-07 5:16 ` [PATCH v3 10/15] powerpc/pseries: machine check use rtas_call_unlocked with args on stack Nicholas Piggin
` (5 subsequent siblings)
14 siblings, 1 reply; 27+ messages in thread
From: Nicholas Piggin @ 2020-04-07 5:16 UTC (permalink / raw)
To: linuxppc-dev
Cc: Mahesh Salgaonkar, Ganesh Goudar, Mahesh Salgaonkar, Nicholas Piggin
This allows rtas_args to be put on the machine check stack, which
avoids a lot of complications with re-entrancy deadlocks.
Reviewed-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
arch/powerpc/kernel/setup_64.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index 438a9befce41..defe05b6b7a9 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -709,7 +709,7 @@ void __init exc_lvl_early_init(void)
*/
void __init emergency_stack_init(void)
{
- u64 limit;
+ u64 limit, mce_limit;
unsigned int i;
/*
@@ -726,7 +726,16 @@ void __init emergency_stack_init(void)
* initialized in kernel/irq.c. These are initialized here in order
* to have emergency stacks available as early as possible.
*/
- limit = min(ppc64_bolted_size(), ppc64_rma_size);
+ limit = mce_limit = min(ppc64_bolted_size(), ppc64_rma_size);
+
+ /*
+ * Machine check on pseries calls rtas, but can't use the static
+ * rtas_args due to a machine check hitting while the lock is held.
+ * rtas args have to be under 4GB, so the machine check stack is
+ * limited to 4GB so args can be put on stack.
+ */
+ if (firmware_has_feature(FW_FEATURE_LPAR) && mce_limit > SZ_4G)
+ mce_limit = SZ_4G;
for_each_possible_cpu(i) {
paca_ptrs[i]->emergency_sp = alloc_stack(limit, i) + THREAD_SIZE;
@@ -736,7 +745,7 @@ void __init emergency_stack_init(void)
paca_ptrs[i]->nmi_emergency_sp = alloc_stack(limit, i) + THREAD_SIZE;
/* emergency stack for machine check exception handling. */
- paca_ptrs[i]->mc_emergency_sp = alloc_stack(limit, i) + THREAD_SIZE;
+ paca_ptrs[i]->mc_emergency_sp = alloc_stack(mce_limit, i) + THREAD_SIZE;
#endif
}
}
--
2.23.0
^ permalink raw reply related [flat|nested] 27+ messages in thread
* [PATCH v3 10/15] powerpc/pseries: machine check use rtas_call_unlocked with args on stack
2020-04-07 5:16 [PATCH v3 00/15] powerpc/64: machine check and system reset fixes Nicholas Piggin
` (8 preceding siblings ...)
2020-04-07 5:16 ` [PATCH v3 09/15] powerpc/pseries: limit machine check stack to 4GB Nicholas Piggin
@ 2020-04-07 5:16 ` Nicholas Piggin
2020-04-07 5:16 ` [PATCH v3 11/15] powerpc/64s: machine check interrupt update NMI accounting Nicholas Piggin
` (4 subsequent siblings)
14 siblings, 0 replies; 27+ messages in thread
From: Nicholas Piggin @ 2020-04-07 5:16 UTC (permalink / raw)
To: linuxppc-dev; +Cc: Mahesh Salgaonkar, Ganesh Goudar, Nicholas Piggin
With the previous patch, machine checks can use rtas_call_unlocked
which avoids the rtas spinlock which would deadlock if a machine
check hits while making an rtas call.
This also avoids the complex rtas error logging which has more rtas calls
and includes kmalloc (which can return memory beyond RMA, which would
also crash).
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
arch/powerpc/platforms/pseries/ras.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/platforms/pseries/ras.c b/arch/powerpc/platforms/pseries/ras.c
index d65bc38bcb8f..4fd138ae26fd 100644
--- a/arch/powerpc/platforms/pseries/ras.c
+++ b/arch/powerpc/platforms/pseries/ras.c
@@ -468,7 +468,15 @@ static struct rtas_error_log *fwnmi_get_errinfo(struct pt_regs *regs)
*/
static void fwnmi_release_errinfo(void)
{
- int ret = rtas_call(ibm_nmi_interlock_token, 0, 1, NULL);
+ struct rtas_args rtas_args;
+ int ret;
+
+ /*
+ * On pseries, the machine check stack is limited to under 4GB, so
+ * args can be on-stack.
+ */
+ rtas_call_unlocked(&rtas_args, ibm_nmi_interlock_token, 0, 1, NULL);
+ ret = be32_to_cpu(rtas_args.rets[0]);
if (ret != 0)
printk(KERN_ERR "FWNMI: nmi-interlock failed: %d\n", ret);
}
--
2.23.0
^ permalink raw reply related [flat|nested] 27+ messages in thread
* [PATCH v3 11/15] powerpc/64s: machine check interrupt update NMI accounting
2020-04-07 5:16 [PATCH v3 00/15] powerpc/64: machine check and system reset fixes Nicholas Piggin
` (9 preceding siblings ...)
2020-04-07 5:16 ` [PATCH v3 10/15] powerpc/pseries: machine check use rtas_call_unlocked with args on stack Nicholas Piggin
@ 2020-04-07 5:16 ` Nicholas Piggin
2020-04-07 5:37 ` Christophe Leroy
2020-04-12 8:46 ` kbuild test robot
2020-04-07 5:16 ` [PATCH v3 12/15] powerpc: ftrace_enabled helper Nicholas Piggin
` (3 subsequent siblings)
14 siblings, 2 replies; 27+ messages in thread
From: Nicholas Piggin @ 2020-04-07 5:16 UTC (permalink / raw)
To: linuxppc-dev; +Cc: Mahesh Salgaonkar, Ganesh Goudar, Nicholas Piggin
machine_check_early is taken as an NMI, so nmi_enter is used there.
machine_check_exception is no longer taken as an NMI (it's invoked
via irq_work in the case a machine check hits in kernel mode), so
remove the nmi_enter from that case.
In NMI context, hash faults don't try to refill the hash table, which
can lead to crashes accessing non-pinned kernel pages. System reset
still has this potential problem.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
arch/powerpc/kernel/mce.c | 7 +++++++
arch/powerpc/kernel/process.c | 2 +-
arch/powerpc/kernel/traps.c | 13 +------------
3 files changed, 9 insertions(+), 13 deletions(-)
diff --git a/arch/powerpc/kernel/mce.c b/arch/powerpc/kernel/mce.c
index 8077b5fb18a7..be7e3f92a7b5 100644
--- a/arch/powerpc/kernel/mce.c
+++ b/arch/powerpc/kernel/mce.c
@@ -574,6 +574,9 @@ EXPORT_SYMBOL_GPL(machine_check_print_event_info);
long machine_check_early(struct pt_regs *regs)
{
long handled = 0;
+ bool nested = in_nmi();
+ if (!nested)
+ nmi_enter();
hv_nmi_check_nonrecoverable(regs);
@@ -582,6 +585,10 @@ long machine_check_early(struct pt_regs *regs)
*/
if (ppc_md.machine_check_early)
handled = ppc_md.machine_check_early(regs);
+
+ if (!nested)
+ nmi_exit();
+
return handled;
}
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 9c21288f8645..44410dd3029f 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1421,7 +1421,7 @@ void show_regs(struct pt_regs * regs)
pr_cont("DAR: "REG" DSISR: %08lx ", regs->dar, regs->dsisr);
#endif
#ifdef CONFIG_PPC64
- pr_cont("IRQMASK: %lx ", regs->softe);
+ pr_cont("IRQMASK: %lx IN_NMI:%d IN_MCE:%d", regs->softe, (int)get_paca()->in_nmi, (int)get_paca()->in_mce);
#endif
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
if (MSR_TM_ACTIVE(regs->msr))
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 3fca22276bb1..9f221772eb73 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -823,9 +823,6 @@ int machine_check_generic(struct pt_regs *regs)
void machine_check_exception(struct pt_regs *regs)
{
int recover = 0;
- bool nested = in_nmi();
- if (!nested)
- nmi_enter();
__this_cpu_inc(irq_stat.mce_exceptions);
@@ -851,20 +848,12 @@ void machine_check_exception(struct pt_regs *regs)
if (check_io_access(regs))
goto bail;
- if (!nested)
- nmi_exit();
-
die("Machine check", regs, SIGBUS);
+bail:
/* Must die if the interrupt is not recoverable */
if (!(regs->msr & MSR_RI))
nmi_panic(regs, "Unrecoverable Machine check");
-
- return;
-
-bail:
- if (!nested)
- nmi_exit();
}
void SMIException(struct pt_regs *regs)
--
2.23.0
^ permalink raw reply related [flat|nested] 27+ messages in thread
* [PATCH v3 12/15] powerpc: ftrace_enabled helper
2020-04-07 5:16 [PATCH v3 00/15] powerpc/64: machine check and system reset fixes Nicholas Piggin
` (10 preceding siblings ...)
2020-04-07 5:16 ` [PATCH v3 11/15] powerpc/64s: machine check interrupt update NMI accounting Nicholas Piggin
@ 2020-04-07 5:16 ` Nicholas Piggin
2020-04-07 5:45 ` Christophe Leroy
2020-04-07 5:16 ` [PATCH v3 13/15] powerpc/64s: machine check do not trace real-mode handler Nicholas Piggin
` (2 subsequent siblings)
14 siblings, 1 reply; 27+ messages in thread
From: Nicholas Piggin @ 2020-04-07 5:16 UTC (permalink / raw)
To: linuxppc-dev
Cc: Mahesh Salgaonkar, Naveen N . Rao, Ganesh Goudar, Nicholas Piggin
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
arch/powerpc/include/asm/ftrace.h | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/arch/powerpc/include/asm/ftrace.h b/arch/powerpc/include/asm/ftrace.h
index f54a08a2cd70..bc76970b6ee5 100644
--- a/arch/powerpc/include/asm/ftrace.h
+++ b/arch/powerpc/include/asm/ftrace.h
@@ -108,9 +108,23 @@ static inline void this_cpu_enable_ftrace(void)
{
get_paca()->ftrace_enabled = 1;
}
+
+/* Disable ftrace on this CPU if possible (may not be implemented) */
+static inline void this_cpu_set_ftrace_enabled(u8 ftrace_enabled)
+{
+ get_paca()->ftrace_enabled = ftrace_enabled;
+}
+
+static inline u8 this_cpu_get_ftrace_enabled(void)
+{
+ return get_paca()->ftrace_enabled;
+}
+
#else /* CONFIG_PPC64 */
static inline void this_cpu_disable_ftrace(void) { }
static inline void this_cpu_enable_ftrace(void) { }
+static inline void this_cpu_set_ftrace_enabled(u8 ftrace_enabled) { }
+static inline u8 this_cpu_get_ftrace_enabled(void) { return 1; }
#endif /* CONFIG_PPC64 */
#endif /* !__ASSEMBLY__ */
--
2.23.0
^ permalink raw reply related [flat|nested] 27+ messages in thread
* [PATCH v3 13/15] powerpc/64s: machine check do not trace real-mode handler
2020-04-07 5:16 [PATCH v3 00/15] powerpc/64: machine check and system reset fixes Nicholas Piggin
` (11 preceding siblings ...)
2020-04-07 5:16 ` [PATCH v3 12/15] powerpc: ftrace_enabled helper Nicholas Piggin
@ 2020-04-07 5:16 ` Nicholas Piggin
2020-04-07 5:45 ` Christophe Leroy
2020-04-07 5:16 ` [PATCH v3 14/15] powerpc/64s: system reset do not trace Nicholas Piggin
2020-04-07 5:16 ` [PATCH v3 15/15] powerpc: make unrecoverable NMIs die instead of panic Nicholas Piggin
14 siblings, 1 reply; 27+ messages in thread
From: Nicholas Piggin @ 2020-04-07 5:16 UTC (permalink / raw)
To: linuxppc-dev
Cc: Mahesh Salgaonkar, Naveen N . Rao, Ganesh Goudar, Nicholas Piggin
Rather than notrace annotations throughout a significant part of the
machine check code across kernel/ pseries/ and powernv/ which can
easily be broken and is infrequently tested, use paca->ftrace_enabled
to blanket-disable tracing of the real-mode non-maskable handler.
Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
arch/powerpc/kernel/mce.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/kernel/mce.c b/arch/powerpc/kernel/mce.c
index be7e3f92a7b5..fd90c0eda229 100644
--- a/arch/powerpc/kernel/mce.c
+++ b/arch/powerpc/kernel/mce.c
@@ -16,6 +16,7 @@
#include <linux/export.h>
#include <linux/irq_work.h>
#include <linux/extable.h>
+#include <linux/ftrace.h>
#include <asm/machdep.h>
#include <asm/mce.h>
@@ -571,10 +572,14 @@ EXPORT_SYMBOL_GPL(machine_check_print_event_info);
*
* regs->nip and regs->msr contains srr0 and ssr1.
*/
-long machine_check_early(struct pt_regs *regs)
+long notrace machine_check_early(struct pt_regs *regs)
{
long handled = 0;
bool nested = in_nmi();
+ u8 ftrace_enabled = this_cpu_get_ftrace_enabled();
+
+ this_cpu_set_ftrace_enabled(0);
+
if (!nested)
nmi_enter();
@@ -589,6 +594,8 @@ long machine_check_early(struct pt_regs *regs)
if (!nested)
nmi_exit();
+ this_cpu_set_ftrace_enabled(ftrace_enabled);
+
return handled;
}
--
2.23.0
^ permalink raw reply related [flat|nested] 27+ messages in thread
* [PATCH v3 14/15] powerpc/64s: system reset do not trace
2020-04-07 5:16 [PATCH v3 00/15] powerpc/64: machine check and system reset fixes Nicholas Piggin
` (12 preceding siblings ...)
2020-04-07 5:16 ` [PATCH v3 13/15] powerpc/64s: machine check do not trace real-mode handler Nicholas Piggin
@ 2020-04-07 5:16 ` Nicholas Piggin
2020-04-07 5:45 ` Christophe Leroy
2020-04-07 5:16 ` [PATCH v3 15/15] powerpc: make unrecoverable NMIs die instead of panic Nicholas Piggin
14 siblings, 1 reply; 27+ messages in thread
From: Nicholas Piggin @ 2020-04-07 5:16 UTC (permalink / raw)
To: linuxppc-dev
Cc: Mahesh Salgaonkar, Naveen N . Rao, Ganesh Goudar, Nicholas Piggin
Similarly to the previous patch, do not trace system reset. This code
is used when there is a crash or hang, and tracing disturbs the system
more and has been known to crash in the crash handling path.
Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
arch/powerpc/kernel/traps.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 9f221772eb73..1beae89bb871 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -443,6 +443,9 @@ void system_reset_exception(struct pt_regs *regs)
unsigned long hsrr0, hsrr1;
bool nested = in_nmi();
bool saved_hsrrs = false;
+ u8 ftrace_enabled = this_cpu_get_ftrace_enabled();
+
+ this_cpu_set_ftrace_enabled(0);
/*
* Avoid crashes in case of nested NMI exceptions. Recoverability
@@ -524,6 +527,8 @@ void system_reset_exception(struct pt_regs *regs)
if (!nested)
nmi_exit();
+ this_cpu_set_ftrace_enabled(ftrace_enabled);
+
/* What should we do here? We could issue a shutdown or hard reset. */
}
--
2.23.0
^ permalink raw reply related [flat|nested] 27+ messages in thread
* [PATCH v3 15/15] powerpc: make unrecoverable NMIs die instead of panic
2020-04-07 5:16 [PATCH v3 00/15] powerpc/64: machine check and system reset fixes Nicholas Piggin
` (13 preceding siblings ...)
2020-04-07 5:16 ` [PATCH v3 14/15] powerpc/64s: system reset do not trace Nicholas Piggin
@ 2020-04-07 5:16 ` Nicholas Piggin
2020-04-07 5:46 ` Christophe Leroy
14 siblings, 1 reply; 27+ messages in thread
From: Nicholas Piggin @ 2020-04-07 5:16 UTC (permalink / raw)
To: linuxppc-dev; +Cc: Mahesh Salgaonkar, Ganesh Goudar, Nicholas Piggin
System Reset and Machine Check interrupts that are not recoverable due
to being nested or interrupting when RI=0 currently panic. This is
not necessary, and can often just kill the current context and recover.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
arch/powerpc/kernel/traps.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 1beae89bb871..afed3de33a9a 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -513,11 +513,11 @@ void system_reset_exception(struct pt_regs *regs)
#ifdef CONFIG_PPC_BOOK3S_64
BUG_ON(get_paca()->in_nmi == 0);
if (get_paca()->in_nmi > 1)
- nmi_panic(regs, "Unrecoverable nested System Reset");
+ die("Unrecoverable nested System Reset", regs, SIGABRT);
#endif
/* Must die if the interrupt is not recoverable */
if (!(regs->msr & MSR_RI))
- nmi_panic(regs, "Unrecoverable System Reset");
+ die("Unrecoverable System Reset", regs, SIGABRT);
if (saved_hsrrs) {
mtspr(SPRN_HSRR0, hsrr0);
@@ -858,7 +858,7 @@ void machine_check_exception(struct pt_regs *regs)
bail:
/* Must die if the interrupt is not recoverable */
if (!(regs->msr & MSR_RI))
- nmi_panic(regs, "Unrecoverable Machine check");
+ die("Unrecoverable Machine check", regs, SIGBUS);
}
void SMIException(struct pt_regs *regs)
--
2.23.0
^ permalink raw reply related [flat|nested] 27+ messages in thread
* Re: [PATCH v3 11/15] powerpc/64s: machine check interrupt update NMI accounting
2020-04-07 5:16 ` [PATCH v3 11/15] powerpc/64s: machine check interrupt update NMI accounting Nicholas Piggin
@ 2020-04-07 5:37 ` Christophe Leroy
2020-05-06 3:50 ` Nicholas Piggin
2020-04-12 8:46 ` kbuild test robot
1 sibling, 1 reply; 27+ messages in thread
From: Christophe Leroy @ 2020-04-07 5:37 UTC (permalink / raw)
To: Nicholas Piggin, linuxppc-dev; +Cc: Mahesh Salgaonkar, Ganesh Goudar
Le 07/04/2020 à 07:16, Nicholas Piggin a écrit :
> machine_check_early is taken as an NMI, so nmi_enter is used there.
> machine_check_exception is no longer taken as an NMI (it's invoked
> via irq_work in the case a machine check hits in kernel mode), so
> remove the nmi_enter from that case.
Euh ... Is that also the case for PPC32 ?
AFAIK machine_check_exception() is called as an NMI on PPC32.
Christophe
>
> In NMI context, hash faults don't try to refill the hash table, which
> can lead to crashes accessing non-pinned kernel pages. System reset
> still has this potential problem.
>
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> ---
> arch/powerpc/kernel/mce.c | 7 +++++++
> arch/powerpc/kernel/process.c | 2 +-
> arch/powerpc/kernel/traps.c | 13 +------------
> 3 files changed, 9 insertions(+), 13 deletions(-)
>
> diff --git a/arch/powerpc/kernel/mce.c b/arch/powerpc/kernel/mce.c
> index 8077b5fb18a7..be7e3f92a7b5 100644
> --- a/arch/powerpc/kernel/mce.c
> +++ b/arch/powerpc/kernel/mce.c
> @@ -574,6 +574,9 @@ EXPORT_SYMBOL_GPL(machine_check_print_event_info);
> long machine_check_early(struct pt_regs *regs)
> {
> long handled = 0;
> + bool nested = in_nmi();
> + if (!nested)
> + nmi_enter();
>
> hv_nmi_check_nonrecoverable(regs);
>
> @@ -582,6 +585,10 @@ long machine_check_early(struct pt_regs *regs)
> */
> if (ppc_md.machine_check_early)
> handled = ppc_md.machine_check_early(regs);
> +
> + if (!nested)
> + nmi_exit();
> +
> return handled;
> }
>
> diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
> index 9c21288f8645..44410dd3029f 100644
> --- a/arch/powerpc/kernel/process.c
> +++ b/arch/powerpc/kernel/process.c
> @@ -1421,7 +1421,7 @@ void show_regs(struct pt_regs * regs)
> pr_cont("DAR: "REG" DSISR: %08lx ", regs->dar, regs->dsisr);
> #endif
> #ifdef CONFIG_PPC64
> - pr_cont("IRQMASK: %lx ", regs->softe);
> + pr_cont("IRQMASK: %lx IN_NMI:%d IN_MCE:%d", regs->softe, (int)get_paca()->in_nmi, (int)get_paca()->in_mce);
> #endif
> #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
> if (MSR_TM_ACTIVE(regs->msr))
> diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
> index 3fca22276bb1..9f221772eb73 100644
> --- a/arch/powerpc/kernel/traps.c
> +++ b/arch/powerpc/kernel/traps.c
> @@ -823,9 +823,6 @@ int machine_check_generic(struct pt_regs *regs)
> void machine_check_exception(struct pt_regs *regs)
> {
> int recover = 0;
> - bool nested = in_nmi();
> - if (!nested)
> - nmi_enter();
>
> __this_cpu_inc(irq_stat.mce_exceptions);
>
> @@ -851,20 +848,12 @@ void machine_check_exception(struct pt_regs *regs)
> if (check_io_access(regs))
> goto bail;
>
> - if (!nested)
> - nmi_exit();
> -
> die("Machine check", regs, SIGBUS);
>
> +bail:
> /* Must die if the interrupt is not recoverable */
> if (!(regs->msr & MSR_RI))
> nmi_panic(regs, "Unrecoverable Machine check");
> -
> - return;
> -
> -bail:
> - if (!nested)
> - nmi_exit();
> }
>
> void SMIException(struct pt_regs *regs)
>
^ permalink raw reply [flat|nested] 27+ messages in thread
* Re: [PATCH v3 09/15] powerpc/pseries: limit machine check stack to 4GB
2020-04-07 5:16 ` [PATCH v3 09/15] powerpc/pseries: limit machine check stack to 4GB Nicholas Piggin
@ 2020-04-07 5:38 ` Christophe Leroy
0 siblings, 0 replies; 27+ messages in thread
From: Christophe Leroy @ 2020-04-07 5:38 UTC (permalink / raw)
To: Nicholas Piggin, linuxppc-dev
Cc: Mahesh Salgaonkar, Ganesh Goudar, Mahesh Salgaonkar
Le 07/04/2020 à 07:16, Nicholas Piggin a écrit :
> This allows rtas_args to be put on the machine check stack, which
> avoids a lot of complications with re-entrancy deadlocks.
>
> Reviewed-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
> ---
> arch/powerpc/kernel/setup_64.c | 15 ++++++++++++---
> 1 file changed, 12 insertions(+), 3 deletions(-)
>
> diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
> index 438a9befce41..defe05b6b7a9 100644
> --- a/arch/powerpc/kernel/setup_64.c
> +++ b/arch/powerpc/kernel/setup_64.c
> @@ -709,7 +709,7 @@ void __init exc_lvl_early_init(void)
> */
> void __init emergency_stack_init(void)
> {
> - u64 limit;
> + u64 limit, mce_limit;
> unsigned int i;
>
> /*
> @@ -726,7 +726,16 @@ void __init emergency_stack_init(void)
> * initialized in kernel/irq.c. These are initialized here in order
> * to have emergency stacks available as early as possible.
> */
> - limit = min(ppc64_bolted_size(), ppc64_rma_size);
> + limit = mce_limit = min(ppc64_bolted_size(), ppc64_rma_size);
> +
> + /*
> + * Machine check on pseries calls rtas, but can't use the static
> + * rtas_args due to a machine check hitting while the lock is held.
> + * rtas args have to be under 4GB, so the machine check stack is
> + * limited to 4GB so args can be put on stack.
> + */
> + if (firmware_has_feature(FW_FEATURE_LPAR) && mce_limit > SZ_4G)
> + mce_limit = SZ_4G;
>
> for_each_possible_cpu(i) {
> paca_ptrs[i]->emergency_sp = alloc_stack(limit, i) + THREAD_SIZE;
> @@ -736,7 +745,7 @@ void __init emergency_stack_init(void)
> paca_ptrs[i]->nmi_emergency_sp = alloc_stack(limit, i) + THREAD_SIZE;
>
> /* emergency stack for machine check exception handling. */
> - paca_ptrs[i]->mc_emergency_sp = alloc_stack(limit, i) + THREAD_SIZE;
> + paca_ptrs[i]->mc_emergency_sp = alloc_stack(mce_limit, i) + THREAD_SIZE;
> #endif
> }
> }
>
^ permalink raw reply [flat|nested] 27+ messages in thread
* Re: [PATCH v3 08/15] powerpc/pseries/ras: fwnmi sreset should not interlock
2020-04-07 5:16 ` [PATCH v3 08/15] powerpc/pseries/ras: fwnmi sreset should not interlock Nicholas Piggin
@ 2020-04-07 5:41 ` Christophe Leroy
0 siblings, 0 replies; 27+ messages in thread
From: Christophe Leroy @ 2020-04-07 5:41 UTC (permalink / raw)
To: Nicholas Piggin, linuxppc-dev; +Cc: Mahesh Salgaonkar, Ganesh Goudar
Le 07/04/2020 à 07:16, Nicholas Piggin a écrit :
> PAPR does not specify that fwnmi sreset should be interlocked, and
> PowerVM (and therefore now QEMU) do not require it.
>
> These "ibm,nmi-interlock" calls are ignored by firmware, but there
> is a possibility that the sreset could have interrupted a machine
> check and release the machine check's interlock too early, corrupting
> it if another machine check came in.
>
> This is an extremely rare case, but it should be fixed for clarity
> and reducing the code executed in the sreset path. Firmware also
> does not provide error information for the sreset case to look at, so
> remove that comment.
>
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> ---
> arch/powerpc/platforms/pseries/ras.c | 46 +++++++++++++++++++---------
> 1 file changed, 32 insertions(+), 14 deletions(-)
>
> diff --git a/arch/powerpc/platforms/pseries/ras.c b/arch/powerpc/platforms/pseries/ras.c
> index 2c60e2be1bc5..d65bc38bcb8f 100644
> --- a/arch/powerpc/platforms/pseries/ras.c
> +++ b/arch/powerpc/platforms/pseries/ras.c
> @@ -406,6 +406,20 @@ static inline struct rtas_error_log *fwnmi_get_errlog(void)
> return (struct rtas_error_log *)local_paca->mce_data_buf;
> }
>
> +static unsigned long *fwnmi_get_savep(struct pt_regs *regs)
> +{
> + unsigned long savep_ra;
> +
> + /* Mask top two bits */
> + savep_ra = regs->gpr[3] & ~(0x3UL << 62);
> + if (!VALID_FWNMI_BUFFER(savep_ra)) {
> + printk(KERN_ERR "FWNMI: corrupt r3 0x%016lx\n", regs->gpr[3]);
pr_err() ?
> + return NULL;
> + }
> +
> + return __va(savep_ra);
> +}
> +
> /*
> * Get the error information for errors coming through the
> * FWNMI vectors. The pt_regs' r3 will be updated to reflect
> @@ -423,20 +437,14 @@ static inline struct rtas_error_log *fwnmi_get_errlog(void)
> */
> static struct rtas_error_log *fwnmi_get_errinfo(struct pt_regs *regs)
> {
> - unsigned long savep_ra;
> unsigned long *savep;
> struct rtas_error_log *h;
>
> - /* Mask top two bits */
> - savep_ra = regs->gpr[3] & ~(0x3UL << 62);
> -
> - if (!VALID_FWNMI_BUFFER(savep_ra)) {
> - printk(KERN_ERR "FWNMI: corrupt r3 0x%016lx\n", regs->gpr[3]);
> + savep = fwnmi_get_savep(regs);
> + if (!savep)
> return NULL;
> - }
>
> - savep = __va(savep_ra);
> - regs->gpr[3] = be64_to_cpu(savep[0]); /* restore original r3 */
> + regs->gpr[3] = be64_to_cpu(savep[0]); /* restore original r3 */
Not sure the above line change is needed.
>
> h = (struct rtas_error_log *)&savep[1];
> /* Use the per cpu buffer from paca to store rtas error log */
> @@ -483,11 +491,21 @@ int pSeries_system_reset_exception(struct pt_regs *regs)
> #endif
>
> if (fwnmi_active) {
> - struct rtas_error_log *errhdr = fwnmi_get_errinfo(regs);
> - if (errhdr) {
> - /* XXX Should look at FWNMI information */
> - }
> - fwnmi_release_errinfo();
> + unsigned long *savep;
> +
> + /*
> + * Firmware (PowerVM and KVM) saves r3 to a save area like
> + * machine check, which is not exactly what PAPR (2.9)
> + * suggests but there is no way to detect otherwise, so this
> + * is the interface now.
> + *
> + * System resets do not save any error log or require an
> + * "ibm,nmi-interlock" rtas call to release.
> + */
> +
> + savep = fwnmi_get_savep(regs);
> + if (savep)
> + regs->gpr[3] = be64_to_cpu(savep[0]); /* restore original r3 */
> }
>
> if (smp_handle_nmi_ipi(regs))
>
Christophe
^ permalink raw reply [flat|nested] 27+ messages in thread
* Re: [PATCH v3 05/15] powerpc/pseries/ras: avoid calling rtas_token in NMI paths
2020-04-07 5:16 ` [PATCH v3 05/15] powerpc/pseries/ras: avoid calling rtas_token in NMI paths Nicholas Piggin
@ 2020-04-07 5:42 ` Christophe Leroy
0 siblings, 0 replies; 27+ messages in thread
From: Christophe Leroy @ 2020-04-07 5:42 UTC (permalink / raw)
To: Nicholas Piggin, linuxppc-dev
Cc: Mahesh Salgaonkar, Ganesh Goudar, Mahesh Salgaonkar
Le 07/04/2020 à 07:16, Nicholas Piggin a écrit :
> In the interest of reducing code and possible failures in the
> machine check and system reset paths, grab the "ibm,nmi-interlock"
> token at init time.
>
> Reviewed-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
> ---
> arch/powerpc/include/asm/firmware.h | 1 +
> arch/powerpc/platforms/pseries/ras.c | 2 +-
> arch/powerpc/platforms/pseries/setup.c | 14 ++++++++++----
> 3 files changed, 12 insertions(+), 5 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/firmware.h b/arch/powerpc/include/asm/firmware.h
> index ca33f4ef6cb4..6003c2e533a0 100644
> --- a/arch/powerpc/include/asm/firmware.h
> +++ b/arch/powerpc/include/asm/firmware.h
> @@ -128,6 +128,7 @@ extern void machine_check_fwnmi(void);
>
> /* This is true if we are using the firmware NMI handler (typically LPAR) */
> extern int fwnmi_active;
> +extern int ibm_nmi_interlock_token;
>
> extern unsigned int __start___fw_ftr_fixup, __stop___fw_ftr_fixup;
>
> diff --git a/arch/powerpc/platforms/pseries/ras.c b/arch/powerpc/platforms/pseries/ras.c
> index aa6208c8d4f0..972b95ebc867 100644
> --- a/arch/powerpc/platforms/pseries/ras.c
> +++ b/arch/powerpc/platforms/pseries/ras.c
> @@ -458,7 +458,7 @@ static struct rtas_error_log *fwnmi_get_errinfo(struct pt_regs *regs)
> */
> static void fwnmi_release_errinfo(void)
> {
> - int ret = rtas_call(rtas_token("ibm,nmi-interlock"), 0, 1, NULL);
> + int ret = rtas_call(ibm_nmi_interlock_token, 0, 1, NULL);
> if (ret != 0)
> printk(KERN_ERR "FWNMI: nmi-interlock failed: %d\n", ret);
> }
> diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
> index 0c8421dd01ab..dd234095ae4f 100644
> --- a/arch/powerpc/platforms/pseries/setup.c
> +++ b/arch/powerpc/platforms/pseries/setup.c
> @@ -83,6 +83,7 @@ unsigned long CMO_PageSize = (ASM_CONST(1) << IOMMU_PAGE_SHIFT_4K);
> EXPORT_SYMBOL(CMO_PageSize);
>
> int fwnmi_active; /* TRUE if an FWNMI handler is present */
> +int ibm_nmi_interlock_token;
>
> static void pSeries_show_cpuinfo(struct seq_file *m)
> {
> @@ -113,9 +114,14 @@ static void __init fwnmi_init(void)
> struct slb_entry *slb_ptr;
> size_t size;
> #endif
> + int ibm_nmi_register_token;
>
> - int ibm_nmi_register = rtas_token("ibm,nmi-register");
> - if (ibm_nmi_register == RTAS_UNKNOWN_SERVICE)
> + ibm_nmi_register_token = rtas_token("ibm,nmi-register");
> + if (ibm_nmi_register_token == RTAS_UNKNOWN_SERVICE)
> + return;
> +
> + ibm_nmi_interlock_token = rtas_token("ibm,nmi-interlock");
> + if (WARN_ON(ibm_nmi_interlock_token == RTAS_UNKNOWN_SERVICE))
> return;
>
> /* If the kernel's not linked at zero we point the firmware at low
> @@ -123,8 +129,8 @@ static void __init fwnmi_init(void)
> system_reset_addr = __pa(system_reset_fwnmi) - PHYSICAL_START;
> machine_check_addr = __pa(machine_check_fwnmi) - PHYSICAL_START;
>
> - if (0 == rtas_call(ibm_nmi_register, 2, 1, NULL, system_reset_addr,
> - machine_check_addr))
> + if (0 == rtas_call(ibm_nmi_register_token, 2, 1, NULL,
> + system_reset_addr, machine_check_addr))
> fwnmi_active = 1;
>
> /*
>
^ permalink raw reply [flat|nested] 27+ messages in thread
* Re: [PATCH v3 12/15] powerpc: ftrace_enabled helper
2020-04-07 5:16 ` [PATCH v3 12/15] powerpc: ftrace_enabled helper Nicholas Piggin
@ 2020-04-07 5:45 ` Christophe Leroy
0 siblings, 0 replies; 27+ messages in thread
From: Christophe Leroy @ 2020-04-07 5:45 UTC (permalink / raw)
To: Nicholas Piggin, linuxppc-dev
Cc: Mahesh Salgaonkar, Naveen N . Rao, Ganesh Goudar
Le 07/04/2020 à 07:16, Nicholas Piggin a écrit :
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
> ---
> arch/powerpc/include/asm/ftrace.h | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>
> diff --git a/arch/powerpc/include/asm/ftrace.h b/arch/powerpc/include/asm/ftrace.h
> index f54a08a2cd70..bc76970b6ee5 100644
> --- a/arch/powerpc/include/asm/ftrace.h
> +++ b/arch/powerpc/include/asm/ftrace.h
> @@ -108,9 +108,23 @@ static inline void this_cpu_enable_ftrace(void)
> {
> get_paca()->ftrace_enabled = 1;
> }
> +
> +/* Disable ftrace on this CPU if possible (may not be implemented) */
> +static inline void this_cpu_set_ftrace_enabled(u8 ftrace_enabled)
> +{
> + get_paca()->ftrace_enabled = ftrace_enabled;
> +}
> +
> +static inline u8 this_cpu_get_ftrace_enabled(void)
> +{
> + return get_paca()->ftrace_enabled;
> +}
> +
> #else /* CONFIG_PPC64 */
> static inline void this_cpu_disable_ftrace(void) { }
> static inline void this_cpu_enable_ftrace(void) { }
> +static inline void this_cpu_set_ftrace_enabled(u8 ftrace_enabled) { }
> +static inline u8 this_cpu_get_ftrace_enabled(void) { return 1; }
> #endif /* CONFIG_PPC64 */
> #endif /* !__ASSEMBLY__ */
>
>
^ permalink raw reply [flat|nested] 27+ messages in thread
* Re: [PATCH v3 13/15] powerpc/64s: machine check do not trace real-mode handler
2020-04-07 5:16 ` [PATCH v3 13/15] powerpc/64s: machine check do not trace real-mode handler Nicholas Piggin
@ 2020-04-07 5:45 ` Christophe Leroy
0 siblings, 0 replies; 27+ messages in thread
From: Christophe Leroy @ 2020-04-07 5:45 UTC (permalink / raw)
To: Nicholas Piggin, linuxppc-dev
Cc: Mahesh Salgaonkar, Naveen N . Rao, Ganesh Goudar
Le 07/04/2020 à 07:16, Nicholas Piggin a écrit :
> Rather than notrace annotations throughout a significant part of the
> machine check code across kernel/ pseries/ and powernv/ which can
> easily be broken and is infrequently tested, use paca->ftrace_enabled
> to blanket-disable tracing of the real-mode non-maskable handler.
>
> Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
> ---
> arch/powerpc/kernel/mce.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/arch/powerpc/kernel/mce.c b/arch/powerpc/kernel/mce.c
> index be7e3f92a7b5..fd90c0eda229 100644
> --- a/arch/powerpc/kernel/mce.c
> +++ b/arch/powerpc/kernel/mce.c
> @@ -16,6 +16,7 @@
> #include <linux/export.h>
> #include <linux/irq_work.h>
> #include <linux/extable.h>
> +#include <linux/ftrace.h>
>
> #include <asm/machdep.h>
> #include <asm/mce.h>
> @@ -571,10 +572,14 @@ EXPORT_SYMBOL_GPL(machine_check_print_event_info);
> *
> * regs->nip and regs->msr contains srr0 and ssr1.
> */
> -long machine_check_early(struct pt_regs *regs)
> +long notrace machine_check_early(struct pt_regs *regs)
> {
> long handled = 0;
> bool nested = in_nmi();
> + u8 ftrace_enabled = this_cpu_get_ftrace_enabled();
> +
> + this_cpu_set_ftrace_enabled(0);
> +
> if (!nested)
> nmi_enter();
>
> @@ -589,6 +594,8 @@ long machine_check_early(struct pt_regs *regs)
> if (!nested)
> nmi_exit();
>
> + this_cpu_set_ftrace_enabled(ftrace_enabled);
> +
> return handled;
> }
>
>
^ permalink raw reply [flat|nested] 27+ messages in thread
* Re: [PATCH v3 14/15] powerpc/64s: system reset do not trace
2020-04-07 5:16 ` [PATCH v3 14/15] powerpc/64s: system reset do not trace Nicholas Piggin
@ 2020-04-07 5:45 ` Christophe Leroy
0 siblings, 0 replies; 27+ messages in thread
From: Christophe Leroy @ 2020-04-07 5:45 UTC (permalink / raw)
To: Nicholas Piggin, linuxppc-dev
Cc: Mahesh Salgaonkar, Naveen N . Rao, Ganesh Goudar
Le 07/04/2020 à 07:16, Nicholas Piggin a écrit :
> Similarly to the previous patch, do not trace system reset. This code
> is used when there is a crash or hang, and tracing disturbs the system
> more and has been known to crash in the crash handling path.
>
> Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
> ---
> arch/powerpc/kernel/traps.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
> index 9f221772eb73..1beae89bb871 100644
> --- a/arch/powerpc/kernel/traps.c
> +++ b/arch/powerpc/kernel/traps.c
> @@ -443,6 +443,9 @@ void system_reset_exception(struct pt_regs *regs)
> unsigned long hsrr0, hsrr1;
> bool nested = in_nmi();
> bool saved_hsrrs = false;
> + u8 ftrace_enabled = this_cpu_get_ftrace_enabled();
> +
> + this_cpu_set_ftrace_enabled(0);
>
> /*
> * Avoid crashes in case of nested NMI exceptions. Recoverability
> @@ -524,6 +527,8 @@ void system_reset_exception(struct pt_regs *regs)
> if (!nested)
> nmi_exit();
>
> + this_cpu_set_ftrace_enabled(ftrace_enabled);
> +
> /* What should we do here? We could issue a shutdown or hard reset. */
> }
>
>
^ permalink raw reply [flat|nested] 27+ messages in thread
* Re: [PATCH v3 15/15] powerpc: make unrecoverable NMIs die instead of panic
2020-04-07 5:16 ` [PATCH v3 15/15] powerpc: make unrecoverable NMIs die instead of panic Nicholas Piggin
@ 2020-04-07 5:46 ` Christophe Leroy
0 siblings, 0 replies; 27+ messages in thread
From: Christophe Leroy @ 2020-04-07 5:46 UTC (permalink / raw)
To: Nicholas Piggin, linuxppc-dev; +Cc: Mahesh Salgaonkar, Ganesh Goudar
Le 07/04/2020 à 07:16, Nicholas Piggin a écrit :
> System Reset and Machine Check interrupts that are not recoverable due
> to being nested or interrupting when RI=0 currently panic. This is
> not necessary, and can often just kill the current context and recover.
>
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
> ---
> arch/powerpc/kernel/traps.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
> index 1beae89bb871..afed3de33a9a 100644
> --- a/arch/powerpc/kernel/traps.c
> +++ b/arch/powerpc/kernel/traps.c
> @@ -513,11 +513,11 @@ void system_reset_exception(struct pt_regs *regs)
> #ifdef CONFIG_PPC_BOOK3S_64
> BUG_ON(get_paca()->in_nmi == 0);
> if (get_paca()->in_nmi > 1)
> - nmi_panic(regs, "Unrecoverable nested System Reset");
> + die("Unrecoverable nested System Reset", regs, SIGABRT);
> #endif
> /* Must die if the interrupt is not recoverable */
> if (!(regs->msr & MSR_RI))
> - nmi_panic(regs, "Unrecoverable System Reset");
> + die("Unrecoverable System Reset", regs, SIGABRT);
>
> if (saved_hsrrs) {
> mtspr(SPRN_HSRR0, hsrr0);
> @@ -858,7 +858,7 @@ void machine_check_exception(struct pt_regs *regs)
> bail:
> /* Must die if the interrupt is not recoverable */
> if (!(regs->msr & MSR_RI))
> - nmi_panic(regs, "Unrecoverable Machine check");
> + die("Unrecoverable Machine check", regs, SIGBUS);
> }
>
> void SMIException(struct pt_regs *regs)
>
^ permalink raw reply [flat|nested] 27+ messages in thread
* Re: [PATCH v3 11/15] powerpc/64s: machine check interrupt update NMI accounting
2020-04-07 5:16 ` [PATCH v3 11/15] powerpc/64s: machine check interrupt update NMI accounting Nicholas Piggin
@ 2020-04-12 8:46 ` kbuild test robot
2020-04-12 8:46 ` kbuild test robot
1 sibling, 0 replies; 27+ messages in thread
From: kbuild test robot @ 2020-04-12 8:46 UTC (permalink / raw)
To: Nicholas Piggin; +Cc: linuxppc-dev, kbuild-all
[-- Attachment #1: Type: text/plain, Size: 4835 bytes --]
Hi Nicholas,
I love your patch! Yet something to improve:
[auto build test ERROR on powerpc/next]
[also build test ERROR on next-20200412]
[cannot apply to tip/perf/core v5.6]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]
url: https://github.com/0day-ci/linux/commits/Nicholas-Piggin/powerpc-64-machine-check-and-system-reset-fixes/20200407-134803
base: https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
config: powerpc-randconfig-a001-20200412 (attached as .config)
compiler: powerpc64-linux-gcc (GCC) 9.3.0
reproduce:
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
GCC_VERSION=9.3.0 make.cross ARCH=powerpc
If you fix the issue, kindly add following tag as appropriate
Reported-by: kbuild test robot <lkp@intel.com>
All errors (new ones prefixed by >>):
In file included from include/linux/kernel.h:15,
from include/asm-generic/bug.h:19,
from arch/powerpc/include/asm/bug.h:109,
from include/linux/bug.h:5,
from arch/powerpc/include/asm/mmu.h:130,
from arch/powerpc/include/asm/paca.h:18,
from arch/powerpc/include/asm/current.h:13,
from include/linux/sched.h:12,
from arch/powerpc/kernel/process.c:14:
arch/powerpc/kernel/process.c: In function 'show_regs':
>> arch/powerpc/kernel/process.c:1424:74: error: 'struct paca_struct' has no member named 'in_nmi'
1424 | pr_cont("IRQMASK: %lx IN_NMI:%d IN_MCE:%d", regs->softe, (int)get_paca()->in_nmi, (int)get_paca()->in_mce);
| ^~
include/linux/printk.h:317:26: note: in definition of macro 'pr_cont'
317 | printk(KERN_CONT fmt, ##__VA_ARGS__)
| ^~~~~~~~~~~
>> arch/powerpc/kernel/process.c:1424:99: error: 'struct paca_struct' has no member named 'in_mce'
1424 | pr_cont("IRQMASK: %lx IN_NMI:%d IN_MCE:%d", regs->softe, (int)get_paca()->in_nmi, (int)get_paca()->in_mce);
| ^~
include/linux/printk.h:317:26: note: in definition of macro 'pr_cont'
317 | printk(KERN_CONT fmt, ##__VA_ARGS__)
| ^~~~~~~~~~~
vim +1424 arch/powerpc/kernel/process.c
1400
1401 void show_regs(struct pt_regs * regs)
1402 {
1403 int i, trap;
1404
1405 show_regs_print_info(KERN_DEFAULT);
1406
1407 printk("NIP: "REG" LR: "REG" CTR: "REG"\n",
1408 regs->nip, regs->link, regs->ctr);
1409 printk("REGS: %px TRAP: %04lx %s (%s)\n",
1410 regs, regs->trap, print_tainted(), init_utsname()->release);
1411 printk("MSR: "REG" ", regs->msr);
1412 print_msr_bits(regs->msr);
1413 pr_cont(" CR: %08lx XER: %08lx\n", regs->ccr, regs->xer);
1414 trap = TRAP(regs);
1415 if ((TRAP(regs) != 0xc00) && cpu_has_feature(CPU_FTR_CFAR))
1416 pr_cont("CFAR: "REG" ", regs->orig_gpr3);
1417 if (trap == 0x200 || trap == 0x300 || trap == 0x600)
1418 #if defined(CONFIG_4xx) || defined(CONFIG_BOOKE)
1419 pr_cont("DEAR: "REG" ESR: "REG" ", regs->dar, regs->dsisr);
1420 #else
1421 pr_cont("DAR: "REG" DSISR: %08lx ", regs->dar, regs->dsisr);
1422 #endif
1423 #ifdef CONFIG_PPC64
> 1424 pr_cont("IRQMASK: %lx IN_NMI:%d IN_MCE:%d", regs->softe, (int)get_paca()->in_nmi, (int)get_paca()->in_mce);
1425 #endif
1426 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
1427 if (MSR_TM_ACTIVE(regs->msr))
1428 pr_cont("\nPACATMSCRATCH: %016llx ", get_paca()->tm_scratch);
1429 #endif
1430
1431 for (i = 0; i < 32; i++) {
1432 if ((i % REGS_PER_LINE) == 0)
1433 pr_cont("\nGPR%02d: ", i);
1434 pr_cont(REG " ", regs->gpr[i]);
1435 if (i == LAST_VOLATILE && !FULL_REGS(regs))
1436 break;
1437 }
1438 pr_cont("\n");
1439 #ifdef CONFIG_KALLSYMS
1440 /*
1441 * Lookup NIP late so we have the best change of getting the
1442 * above info out without failing
1443 */
1444 printk("NIP ["REG"] %pS\n", regs->nip, (void *)regs->nip);
1445 printk("LR ["REG"] %pS\n", regs->link, (void *)regs->link);
1446 #endif
1447 show_stack(current, (unsigned long *) regs->gpr[1]);
1448 if (!user_mode(regs))
1449 show_instructions(regs);
1450 }
1451
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 30335 bytes --]
^ permalink raw reply [flat|nested] 27+ messages in thread
* Re: [PATCH v3 11/15] powerpc/64s: machine check interrupt update NMI accounting
@ 2020-04-12 8:46 ` kbuild test robot
0 siblings, 0 replies; 27+ messages in thread
From: kbuild test robot @ 2020-04-12 8:46 UTC (permalink / raw)
To: kbuild-all
[-- Attachment #1: Type: text/plain, Size: 4944 bytes --]
Hi Nicholas,
I love your patch! Yet something to improve:
[auto build test ERROR on powerpc/next]
[also build test ERROR on next-20200412]
[cannot apply to tip/perf/core v5.6]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]
url: https://github.com/0day-ci/linux/commits/Nicholas-Piggin/powerpc-64-machine-check-and-system-reset-fixes/20200407-134803
base: https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
config: powerpc-randconfig-a001-20200412 (attached as .config)
compiler: powerpc64-linux-gcc (GCC) 9.3.0
reproduce:
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
GCC_VERSION=9.3.0 make.cross ARCH=powerpc
If you fix the issue, kindly add following tag as appropriate
Reported-by: kbuild test robot <lkp@intel.com>
All errors (new ones prefixed by >>):
In file included from include/linux/kernel.h:15,
from include/asm-generic/bug.h:19,
from arch/powerpc/include/asm/bug.h:109,
from include/linux/bug.h:5,
from arch/powerpc/include/asm/mmu.h:130,
from arch/powerpc/include/asm/paca.h:18,
from arch/powerpc/include/asm/current.h:13,
from include/linux/sched.h:12,
from arch/powerpc/kernel/process.c:14:
arch/powerpc/kernel/process.c: In function 'show_regs':
>> arch/powerpc/kernel/process.c:1424:74: error: 'struct paca_struct' has no member named 'in_nmi'
1424 | pr_cont("IRQMASK: %lx IN_NMI:%d IN_MCE:%d", regs->softe, (int)get_paca()->in_nmi, (int)get_paca()->in_mce);
| ^~
include/linux/printk.h:317:26: note: in definition of macro 'pr_cont'
317 | printk(KERN_CONT fmt, ##__VA_ARGS__)
| ^~~~~~~~~~~
>> arch/powerpc/kernel/process.c:1424:99: error: 'struct paca_struct' has no member named 'in_mce'
1424 | pr_cont("IRQMASK: %lx IN_NMI:%d IN_MCE:%d", regs->softe, (int)get_paca()->in_nmi, (int)get_paca()->in_mce);
| ^~
include/linux/printk.h:317:26: note: in definition of macro 'pr_cont'
317 | printk(KERN_CONT fmt, ##__VA_ARGS__)
| ^~~~~~~~~~~
vim +1424 arch/powerpc/kernel/process.c
1400
1401 void show_regs(struct pt_regs * regs)
1402 {
1403 int i, trap;
1404
1405 show_regs_print_info(KERN_DEFAULT);
1406
1407 printk("NIP: "REG" LR: "REG" CTR: "REG"\n",
1408 regs->nip, regs->link, regs->ctr);
1409 printk("REGS: %px TRAP: %04lx %s (%s)\n",
1410 regs, regs->trap, print_tainted(), init_utsname()->release);
1411 printk("MSR: "REG" ", regs->msr);
1412 print_msr_bits(regs->msr);
1413 pr_cont(" CR: %08lx XER: %08lx\n", regs->ccr, regs->xer);
1414 trap = TRAP(regs);
1415 if ((TRAP(regs) != 0xc00) && cpu_has_feature(CPU_FTR_CFAR))
1416 pr_cont("CFAR: "REG" ", regs->orig_gpr3);
1417 if (trap == 0x200 || trap == 0x300 || trap == 0x600)
1418 #if defined(CONFIG_4xx) || defined(CONFIG_BOOKE)
1419 pr_cont("DEAR: "REG" ESR: "REG" ", regs->dar, regs->dsisr);
1420 #else
1421 pr_cont("DAR: "REG" DSISR: %08lx ", regs->dar, regs->dsisr);
1422 #endif
1423 #ifdef CONFIG_PPC64
> 1424 pr_cont("IRQMASK: %lx IN_NMI:%d IN_MCE:%d", regs->softe, (int)get_paca()->in_nmi, (int)get_paca()->in_mce);
1425 #endif
1426 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
1427 if (MSR_TM_ACTIVE(regs->msr))
1428 pr_cont("\nPACATMSCRATCH: %016llx ", get_paca()->tm_scratch);
1429 #endif
1430
1431 for (i = 0; i < 32; i++) {
1432 if ((i % REGS_PER_LINE) == 0)
1433 pr_cont("\nGPR%02d: ", i);
1434 pr_cont(REG " ", regs->gpr[i]);
1435 if (i == LAST_VOLATILE && !FULL_REGS(regs))
1436 break;
1437 }
1438 pr_cont("\n");
1439 #ifdef CONFIG_KALLSYMS
1440 /*
1441 * Lookup NIP late so we have the best change of getting the
1442 * above info out without failing
1443 */
1444 printk("NIP ["REG"] %pS\n", regs->nip, (void *)regs->nip);
1445 printk("LR ["REG"] %pS\n", regs->link, (void *)regs->link);
1446 #endif
1447 show_stack(current, (unsigned long *) regs->gpr[1]);
1448 if (!user_mode(regs))
1449 show_instructions(regs);
1450 }
1451
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org
[-- Attachment #2: config.gz --]
[-- Type: application/gzip, Size: 30335 bytes --]
^ permalink raw reply [flat|nested] 27+ messages in thread
* Re: [PATCH v3 11/15] powerpc/64s: machine check interrupt update NMI accounting
2020-04-07 5:37 ` Christophe Leroy
@ 2020-05-06 3:50 ` Nicholas Piggin
0 siblings, 0 replies; 27+ messages in thread
From: Nicholas Piggin @ 2020-05-06 3:50 UTC (permalink / raw)
To: Christophe Leroy, linuxppc-dev; +Cc: Mahesh Salgaonkar, Ganesh Goudar
Excerpts from Christophe Leroy's message of April 7, 2020 3:37 pm:
>
>
> Le 07/04/2020 à 07:16, Nicholas Piggin a écrit :
>> machine_check_early is taken as an NMI, so nmi_enter is used there.
>> machine_check_exception is no longer taken as an NMI (it's invoked
>> via irq_work in the case a machine check hits in kernel mode), so
>> remove the nmi_enter from that case.
>
> Euh ... Is that also the case for PPC32 ?
>
> AFAIK machine_check_exception() is called as an NMI on PPC32.
Sorry I missed your comment. You're right, I'll make this change
depend on 64S. Thanks for reviewing them.
Thanks,
Nick
^ permalink raw reply [flat|nested] 27+ messages in thread
end of thread, other threads:[~2020-05-06 4:40 UTC | newest]
Thread overview: 27+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-04-07 5:16 [PATCH v3 00/15] powerpc/64: machine check and system reset fixes Nicholas Piggin
2020-04-07 5:16 ` [PATCH v3 01/15] powerpc/64s/exception: Fix machine check no-loss idle wakeup Nicholas Piggin
2020-04-07 5:16 ` [PATCH v3 02/15] powerpc/64s/exceptions: Fix in_mce accounting in unrecoverable path Nicholas Piggin
2020-04-07 5:16 ` [PATCH v3 03/15] powerpc/64s/exceptions: Change irq reconcile for NMIs from reusing _DAR to RESULT Nicholas Piggin
2020-04-07 5:16 ` [PATCH v3 04/15] powerpc/64s/exceptions: machine check reconcile irq state Nicholas Piggin
2020-04-07 5:16 ` [PATCH v3 05/15] powerpc/pseries/ras: avoid calling rtas_token in NMI paths Nicholas Piggin
2020-04-07 5:42 ` Christophe Leroy
2020-04-07 5:16 ` [PATCH v3 06/15] powerpc/pseries/ras: FWNMI_VALID off by one Nicholas Piggin
2020-04-07 5:16 ` [PATCH v3 07/15] powerpc/pseries/ras: fwnmi avoid modifying r3 in error case Nicholas Piggin
2020-04-07 5:16 ` [PATCH v3 08/15] powerpc/pseries/ras: fwnmi sreset should not interlock Nicholas Piggin
2020-04-07 5:41 ` Christophe Leroy
2020-04-07 5:16 ` [PATCH v3 09/15] powerpc/pseries: limit machine check stack to 4GB Nicholas Piggin
2020-04-07 5:38 ` Christophe Leroy
2020-04-07 5:16 ` [PATCH v3 10/15] powerpc/pseries: machine check use rtas_call_unlocked with args on stack Nicholas Piggin
2020-04-07 5:16 ` [PATCH v3 11/15] powerpc/64s: machine check interrupt update NMI accounting Nicholas Piggin
2020-04-07 5:37 ` Christophe Leroy
2020-05-06 3:50 ` Nicholas Piggin
2020-04-12 8:46 ` kbuild test robot
2020-04-12 8:46 ` kbuild test robot
2020-04-07 5:16 ` [PATCH v3 12/15] powerpc: ftrace_enabled helper Nicholas Piggin
2020-04-07 5:45 ` Christophe Leroy
2020-04-07 5:16 ` [PATCH v3 13/15] powerpc/64s: machine check do not trace real-mode handler Nicholas Piggin
2020-04-07 5:45 ` Christophe Leroy
2020-04-07 5:16 ` [PATCH v3 14/15] powerpc/64s: system reset do not trace Nicholas Piggin
2020-04-07 5:45 ` Christophe Leroy
2020-04-07 5:16 ` [PATCH v3 15/15] powerpc: make unrecoverable NMIs die instead of panic Nicholas Piggin
2020-04-07 5:46 ` Christophe Leroy
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