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authorHari Bathini <hbathini@linux.vnet.ibm.com>2014-12-18 23:36:55 +0530
committerMichael Ellerman <mpe@ellerman.id.au>2014-12-29 15:44:53 +1100
commitc1caae3de46a072d0855729aed6e793e536a4a55 (patch)
tree7a21e64d9432ba26cd313cc1038c4cc1be049af8
parentpowerpc: Wire up sys_execveat() syscall (diff)
downloadlinux-dev-c1caae3de46a072d0855729aed6e793e536a4a55.tar.xz
linux-dev-c1caae3de46a072d0855729aed6e793e536a4a55.zip
powerpc/kdump: Ignore failure in enabling big endian exception during crash
In LE kernel, we currently have a hack for kexec that resets the exception endian before starting a new kernel as the kernel that is loaded could be a big endian or a little endian kernel. In kdump case, resetting exception endian fails when one or more cpus is disabled. But we can ignore the failure and still go ahead, as in most cases crashkernel will be of same endianess as primary kernel and reseting endianess is not even needed in those cases. This patch adds a new inline function to say if this is kdump path. This function is used at places where such a check is needed. Signed-off-by: Hari Bathini <hbathini@linux.vnet.ibm.com> [mpe: Rename to kdump_in_progress(), use bool, and edit comment] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
-rw-r--r--arch/powerpc/include/asm/kexec.h10
-rw-r--r--arch/powerpc/kernel/machine_kexec_64.c2
-rw-r--r--arch/powerpc/platforms/pseries/lpar.c8
3 files changed, 18 insertions, 2 deletions
diff --git a/arch/powerpc/include/asm/kexec.h b/arch/powerpc/include/asm/kexec.h
index 19c36cba37c4..a46f5f45570c 100644
--- a/arch/powerpc/include/asm/kexec.h
+++ b/arch/powerpc/include/asm/kexec.h
@@ -86,6 +86,11 @@ extern int overlaps_crashkernel(unsigned long start, unsigned long size);
extern void reserve_crashkernel(void);
extern void machine_kexec_mask_interrupts(void);
+static inline bool kdump_in_progress(void)
+{
+ return crashing_cpu >= 0;
+}
+
#else /* !CONFIG_KEXEC */
static inline void crash_kexec_secondary(struct pt_regs *regs) { }
@@ -106,6 +111,11 @@ static inline int crash_shutdown_unregister(crash_shutdown_t handler)
return 0;
}
+static inline bool kdump_in_progress(void)
+{
+ return false;
+}
+
#endif /* CONFIG_KEXEC */
#endif /* ! __ASSEMBLY__ */
#endif /* __KERNEL__ */
diff --git a/arch/powerpc/kernel/machine_kexec_64.c b/arch/powerpc/kernel/machine_kexec_64.c
index 879b3aacac32..f96d1ec24189 100644
--- a/arch/powerpc/kernel/machine_kexec_64.c
+++ b/arch/powerpc/kernel/machine_kexec_64.c
@@ -330,7 +330,7 @@ void default_machine_kexec(struct kimage *image)
* using debugger IPI.
*/
- if (crashing_cpu == -1)
+ if (!kdump_in_progress())
kexec_prepare_cpus();
pr_debug("kexec: Starting switchover sequence.\n");
diff --git a/arch/powerpc/platforms/pseries/lpar.c b/arch/powerpc/platforms/pseries/lpar.c
index 469751d92004..b5682fd6c984 100644
--- a/arch/powerpc/platforms/pseries/lpar.c
+++ b/arch/powerpc/platforms/pseries/lpar.c
@@ -43,6 +43,7 @@
#include <asm/trace.h>
#include <asm/firmware.h>
#include <asm/plpar_wrappers.h>
+#include <asm/kexec.h>
#include <asm/fadump.h>
#include "pseries.h"
@@ -267,8 +268,13 @@ static void pSeries_lpar_hptab_clear(void)
* out to the user, but at least this will stop us from
* continuing on further and creating an even more
* difficult to debug situation.
+ *
+ * There is a known problem when kdump'ing, if cpus are offline
+ * the above call will fail. Rather than panicking again, keep
+ * going and hope the kdump kernel is also little endian, which
+ * it usually is.
*/
- if (rc)
+ if (rc && !kdump_in_progress())
panic("Could not enable big endian exceptions");
}
#endif