[PATCH 3/4 Vivid SRU v2] powerpc/powernv: Invoke opal_cec_reboot2() on unrecoverable machine check errors.
tim.gardner at canonical.com
tim.gardner at canonical.com
Tue Oct 6 18:59:32 UTC 2015
From: Mahesh Salgaonkar <mahesh at linux.vnet.ibm.com>
BugLink: http://bugs.launchpad.net/bugs/1482343
On non-recoverable MCE errors in kernel space, Linux kernel panics
and system reboots. On BMC based system opal-prd runs as a daemon
in the host. Hence, kernel crash may prevent opal-prd to detect and
analyze this MCE error. This may land us in a situation where the faulty
memory never gets de-configured and Linux would keep hitting same MCE error
again and again. If this happens in early stage of kernel initialization,
then Linux will keep crashing and rebooting in a loop.
This patch fixes this issue by invoking new opal_cec_reboot2() call with
reboot type OPAL_REBOOT_PLATFORM_ERROR to inform BMC/OCC about this
error, so that BMC can collect relevant data for error analysis and
decide what component to de-configure before rebooting.
This patch is dependent on OPAL patchset posted on skiboot mailing list
at https://lists.ozlabs.org/pipermail/skiboot/2015-July/001771.html that
introduces opal_cec_reboot2() opal call.
Signed-off-by: Mahesh Salgaonkar <mahesh at linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe at ellerman.id.au>
(back ported from commit e784b6499d9cba83b7f3f032b7ee01f7ca96ad91)
Signed-off-by: Tim Gardner <tim.gardner at canonical.com>
Conflicts:
arch/powerpc/include/asm/opal-api.h
---
arch/powerpc/include/asm/opal-api.h | 9 ++++++-
arch/powerpc/include/asm/opal.h | 1 +
arch/powerpc/platforms/powernv/opal-wrappers.S | 1 +
arch/powerpc/platforms/powernv/opal.c | 35 ++++++++++++++++++++++++++
4 files changed, 45 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/include/asm/opal-api.h b/arch/powerpc/include/asm/opal-api.h
index 56844ed..16bc0df 100644
--- a/arch/powerpc/include/asm/opal-api.h
+++ b/arch/powerpc/include/asm/opal-api.h
@@ -154,7 +154,8 @@
#define OPAL_FLASH_WRITE 111
#define OPAL_FLASH_ERASE 112
#define OPAL_PRD_MSG 113
-#define OPAL_LAST 113
+#define OPAL_CEC_REBOOT2 116
+#define OPAL_LAST 116
/* Device tree flags */
@@ -857,6 +858,12 @@ struct opal_i2c_request {
__be64 buffer_ra; /* Buffer real address */
};
+/* Argument to OPAL_CEC_REBOOT2() */
+enum {
+ OPAL_REBOOT_NORMAL = 0,
+ OPAL_REBOOT_PLATFORM_ERROR = 1,
+};
+
#endif /* __ASSEMBLY__ */
#endif /* __OPAL_API_H */
diff --git a/arch/powerpc/include/asm/opal.h b/arch/powerpc/include/asm/opal.h
index 4375cb4..ac93024 100644
--- a/arch/powerpc/include/asm/opal.h
+++ b/arch/powerpc/include/asm/opal.h
@@ -44,6 +44,7 @@ int64_t opal_tpo_write(uint64_t token, uint32_t year_mon_day,
uint32_t hour_min);
int64_t opal_cec_power_down(uint64_t request);
int64_t opal_cec_reboot(void);
+int64_t opal_cec_reboot2(uint32_t reboot_type, char *diag);
int64_t opal_read_nvram(uint64_t buffer, uint64_t size, uint64_t offset);
int64_t opal_write_nvram(uint64_t buffer, uint64_t size, uint64_t offset);
int64_t opal_handle_interrupt(uint64_t isn, __be64 *outstanding_event_mask);
diff --git a/arch/powerpc/platforms/powernv/opal-wrappers.S b/arch/powerpc/platforms/powernv/opal-wrappers.S
index 5e0e732..9e4e539 100644
--- a/arch/powerpc/platforms/powernv/opal-wrappers.S
+++ b/arch/powerpc/platforms/powernv/opal-wrappers.S
@@ -202,6 +202,7 @@ OPAL_CALL(opal_rtc_read, OPAL_RTC_READ);
OPAL_CALL(opal_rtc_write, OPAL_RTC_WRITE);
OPAL_CALL(opal_cec_power_down, OPAL_CEC_POWER_DOWN);
OPAL_CALL(opal_cec_reboot, OPAL_CEC_REBOOT);
+OPAL_CALL(opal_cec_reboot2, OPAL_CEC_REBOOT2);
OPAL_CALL(opal_read_nvram, OPAL_READ_NVRAM);
OPAL_CALL(opal_write_nvram, OPAL_WRITE_NVRAM);
OPAL_CALL(opal_handle_interrupt, OPAL_HANDLE_INTERRUPT);
diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c
index 3f34413..5498629 100644
--- a/arch/powerpc/platforms/powernv/opal.c
+++ b/arch/powerpc/platforms/powernv/opal.c
@@ -523,6 +523,7 @@ static int opal_recover_mce(struct pt_regs *regs,
int opal_machine_check(struct pt_regs *regs)
{
struct machine_check_event evt;
+ int ret;
if (!get_mce_event(&evt, MCE_EVENT_RELEASE))
return 0;
@@ -537,6 +538,40 @@ int opal_machine_check(struct pt_regs *regs)
if (opal_recover_mce(regs, &evt))
return 1;
+
+ /*
+ * Unrecovered machine check, we are heading to panic path.
+ *
+ * We may have hit this MCE in very early stage of kernel
+ * initialization even before opal-prd has started running. If
+ * this is the case then this MCE error may go un-noticed or
+ * un-analyzed if we go down panic path. We need to inform
+ * BMC/OCC about this error so that they can collect relevant
+ * data for error analysis before rebooting.
+ * Use opal_cec_reboot2(OPAL_REBOOT_PLATFORM_ERROR) to do so.
+ * This function may not return on BMC based system.
+ */
+ ret = opal_cec_reboot2(OPAL_REBOOT_PLATFORM_ERROR,
+ "Unrecoverable Machine Check exception");
+ if (ret == OPAL_UNSUPPORTED) {
+ pr_emerg("Reboot type %d not supported\n",
+ OPAL_REBOOT_PLATFORM_ERROR);
+ }
+
+ /*
+ * We reached here. There can be three possibilities:
+ * 1. We are running on a firmware level that do not support
+ * opal_cec_reboot2()
+ * 2. We are running on a firmware level that do not support
+ * OPAL_REBOOT_PLATFORM_ERROR reboot type.
+ * 3. We are running on FSP based system that does not need opal
+ * to trigger checkstop explicitly for error analysis. The FSP
+ * PRD component would have already got notified about this
+ * error through other channels.
+ *
+ * In any case, let us just fall through. We anyway heading
+ * down to panic path.
+ */
return 0;
}
--
1.9.1
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