As explained by commit daf00ae71dad ("powerpc/traps: restore
recoverability of machine_check interrupts"), die() can't be called from
within nmi_enter to nicely kill a process context that was interrupted.
nmi_exit must be called first.
This adds a function die_mce which takes care of this for machine check
handlers.
Signed-off-by: Nicholas Piggin <npig...@gmail.com>
---
arch/powerpc/include/asm/bug.h | 1 +
arch/powerpc/kernel/traps.c | 21 +++++++++++++++------
arch/powerpc/platforms/powernv/opal.c | 2 +-
arch/powerpc/platforms/pseries/ras.c | 2 +-
4 files changed, 18 insertions(+), 8 deletions(-)
diff --git a/arch/powerpc/include/asm/bug.h b/arch/powerpc/include/asm/bug.h
index 8f09ddae9305..c10ae0a9bbaf 100644
--- a/arch/powerpc/include/asm/bug.h
+++ b/arch/powerpc/include/asm/bug.h
@@ -118,6 +118,7 @@ void do_bad_page_fault_segv(struct pt_regs *regs);
extern void _exception(int, struct pt_regs *, int, unsigned long);
extern void _exception_pkey(struct pt_regs *, unsigned long, int);
extern void die(const char *, struct pt_regs *, long);
+void die_mce(const char *str, struct pt_regs *regs, long err);
extern bool die_will_crash(void);
extern void panic_flush_kmsg_start(void);
extern void panic_flush_kmsg_end(void);
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 6691774fe1fb..f9ef183a5454 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -789,6 +789,19 @@ int machine_check_generic(struct pt_regs *regs)
}
#endif /* everything else */
+void die_mce(const char *str, struct pt_regs *regs, long err)
+{
+ /*
+ * The machine check wants to kill the interrupted context, but
+ * do_exit() checks for in_interrupt() and panics in that case, so
+ * exit the irq/nmi before calling die.
+ */
+ if (!IS_ENABLED(CONFIG_PPC_BOOK3S_64))
+ nmi_exit();
+ die(str, regs, err);
+}
+NOKPROBE_SYMBOL(die_mce);
+
void machine_check_exception(struct pt_regs *regs)
{
int recover = 0;
@@ -831,15 +844,11 @@ void machine_check_exception(struct pt_regs *regs)
if (check_io_access(regs))
goto bail;
- if (nmi) nmi_exit();
-
- die("Machine check", regs, SIGBUS);
+ die_mce("Machine check", regs, SIGBUS);
/* Must die if the interrupt is not recoverable */
if (!(regs->msr & MSR_RI))
- die("Unrecoverable Machine check", regs, SIGBUS);
-
- return;
+ die_mce("Unrecoverable Machine check", regs, SIGBUS);
bail:
if (nmi) nmi_exit();
diff --git a/arch/powerpc/platforms/powernv/opal.c
b/arch/powerpc/platforms/powernv/opal.c
index c61c3b62c8c6..303d7c775740 100644
--- a/arch/powerpc/platforms/powernv/opal.c
+++ b/arch/powerpc/platforms/powernv/opal.c
@@ -624,7 +624,7 @@ static int opal_recover_mce(struct pt_regs *regs,
*/
recovered = 0;
} else {
- die("Machine check", regs, SIGBUS);
+ die_mce("Machine check", regs, SIGBUS);
recovered = 1;
}
}
diff --git a/arch/powerpc/platforms/pseries/ras.c
b/arch/powerpc/platforms/pseries/ras.c
index 149cec2212e6..2d9f985fd13a 100644
--- a/arch/powerpc/platforms/pseries/ras.c
+++ b/arch/powerpc/platforms/pseries/ras.c
@@ -813,7 +813,7 @@ static int recover_mce(struct pt_regs *regs, struct
machine_check_event *evt)
*/
recovered = 0;
} else {
- die("Machine check", regs, SIGBUS);
+ die_mce("Machine check", regs, SIGBUS);
recovered = 1;
}
}
--
2.23.0
