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authorNicholas Piggin <npiggin@gmail.com>2017-12-24 02:49:23 +1000
committerMichael Ellerman <mpe@ellerman.id.au>2018-01-22 11:44:24 +1100
commit35adacd6fc48d658419522f192a3c8b2785612da (patch)
tree630cbacd918fbae3b2b920fe44383ef5593e3e57
parenta08082f8e4e1c292df174a9ed303cfbff2fbe2cb (diff)
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powerpc/pseries, ps3: panic flush kernel messages before halting system
Platforms with a panic handler that halts the system can have problems getting kernel messages out, because the panic notifiers are called before kernel/panic.c does its flushing of printk buffers an console etc. This was attempted to be solved with commit a3b2cb30f252 ("powerpc: Do not call ppc_md.panic in fadump panic notifier"), but that wasn't the right approach and caused other problems, and was reverted by commit ab9dbf771ff9. Instead, the powernv shutdown paths have already had a similar problem, fixed by taking the message flushing sequence from kernel/panic.c. That's a little bit ugly, but while we have the code duplicated, it will work for this case as well. So have ppc panic handlers do the same flushing before they terminate. Without this patch, a qemu pseries_le_defconfig guest stops silently when issued the nmi command when xmon is off and no crash dumpers enabled. Afterwards, an oops is printed by each CPU as expected. Fixes: ab9dbf771ff9 ("Revert "powerpc: Do not call ppc_md.panic in fadump panic notifier"") Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
-rw-r--r--arch/powerpc/include/asm/bug.h3
-rw-r--r--arch/powerpc/kernel/traps.c24
-rw-r--r--arch/powerpc/platforms/powernv/opal.c18
-rw-r--r--arch/powerpc/platforms/ps3/setup.c1
-rw-r--r--arch/powerpc/platforms/pseries/setup.c8
5 files changed, 38 insertions, 16 deletions
diff --git a/arch/powerpc/include/asm/bug.h b/arch/powerpc/include/asm/bug.h
index 97c38472b924..fd06dbe7d7d3 100644
--- a/arch/powerpc/include/asm/bug.h
+++ b/arch/powerpc/include/asm/bug.h
@@ -136,7 +136,8 @@ extern void _exception(int, struct pt_regs *, int, unsigned long);
extern void _exception_pkey(int, struct pt_regs *, int, unsigned long, int);
extern void die(const char *, struct pt_regs *, long);
extern bool die_will_crash(void);
-
+extern void panic_flush_kmsg_start(void);
+extern void panic_flush_kmsg_end(void);
#endif /* !__ASSEMBLY__ */
#endif /* __KERNEL__ */
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index cb07d6519783..4260c73461a3 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -39,6 +39,8 @@
#include <linux/ratelimit.h>
#include <linux/context_tracking.h>
#include <linux/smp.h>
+#include <linux/console.h>
+#include <linux/kmsg_dump.h>
#include <asm/emulated_ops.h>
#include <asm/pgtable.h>
@@ -143,6 +145,28 @@ static int die_owner = -1;
static unsigned int die_nest_count;
static int die_counter;
+extern void panic_flush_kmsg_start(void)
+{
+ /*
+ * These are mostly taken from kernel/panic.c, but tries to do
+ * relatively minimal work. Don't use delay functions (TB may
+ * be broken), don't crash dump (need to set a firmware log),
+ * don't run notifiers. We do want to get some information to
+ * Linux console.
+ */
+ console_verbose();
+ bust_spinlocks(1);
+}
+
+extern void panic_flush_kmsg_end(void)
+{
+ printk_safe_flush_on_panic();
+ kmsg_dump(KMSG_DUMP_PANIC);
+ bust_spinlocks(0);
+ debug_locks_off();
+ console_flush_on_panic();
+}
+
static unsigned long oops_begin(struct pt_regs *regs)
{
int cpu;
diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c
index 69b5263fc9e3..c15182765ff5 100644
--- a/arch/powerpc/platforms/powernv/opal.c
+++ b/arch/powerpc/platforms/powernv/opal.c
@@ -461,24 +461,14 @@ static int opal_recover_mce(struct pt_regs *regs,
void pnv_platform_error_reboot(struct pt_regs *regs, const char *msg)
{
- /*
- * This is mostly taken from kernel/panic.c, but tries to do
- * relatively minimal work. Don't use delay functions (TB may
- * be broken), don't crash dump (need to set a firmware log),
- * don't run notifiers. We do want to get some information to
- * Linux console.
- */
- console_verbose();
- bust_spinlocks(1);
+ panic_flush_kmsg_start();
+
pr_emerg("Hardware platform error: %s\n", msg);
if (regs)
show_regs(regs);
smp_send_stop();
- printk_safe_flush_on_panic();
- kmsg_dump(KMSG_DUMP_PANIC);
- bust_spinlocks(0);
- debug_locks_off();
- console_flush_on_panic();
+
+ panic_flush_kmsg_end();
/*
* Don't bother to shut things down because this will
diff --git a/arch/powerpc/platforms/ps3/setup.c b/arch/powerpc/platforms/ps3/setup.c
index 6244bc849469..77a37520068d 100644
--- a/arch/powerpc/platforms/ps3/setup.c
+++ b/arch/powerpc/platforms/ps3/setup.c
@@ -113,6 +113,7 @@ static void ps3_panic(char *str)
printk(" System does not reboot automatically.\n");
printk(" Please press POWER button.\n");
printk("\n");
+ panic_flush_kmsg_end();
while(1)
lv1_pause(1);
diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index db76963e693d..42e9cf0b3180 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -533,6 +533,12 @@ static void __init pSeries_setup_arch(void)
ppc_md.pcibios_root_bridge_prepare = pseries_root_bridge_prepare;
}
+static void pseries_panic(char *str)
+{
+ panic_flush_kmsg_end();
+ rtas_os_term(str);
+}
+
static int __init pSeries_init_panel(void)
{
/* Manually leave the kernel version on the panel. */
@@ -761,7 +767,7 @@ define_machine(pseries) {
.pcibios_fixup = pSeries_final_fixup,
.restart = rtas_restart,
.halt = rtas_halt,
- .panic = rtas_os_term,
+ .panic = pseries_panic,
.get_boot_time = rtas_get_boot_time,
.get_rtc_time = rtas_get_rtc_time,
.set_rtc_time = rtas_set_rtc_time,