Re: [PATCH v3 11/15] powerpc/64s: machine check interrupt update NMI accounting
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
Re: [PATCH v3 11/15] powerpc/64s: machine check interrupt update NMI accounting
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
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 *)
Re: [PATCH v3 11/15] powerpc/64s: machine check interrupt update NMI accounting
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
---
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)
[PATCH v3 11/15] powerpc/64s: machine check interrupt update NMI accounting
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
---
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
