[PATCH v6 20/39] powerpc: introduce die_mce
From: Nicholas Piggin <npiggin@gmail.com>
Date: 2021-01-15 17:41:50
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
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 <npiggin@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