From 36350e00696df148507246c817cf6f86329479fd Mon Sep 17 00:00:00 2001 From: Mark Nelson Date: Sun, 7 Feb 2010 16:45:12 +0000 Subject: [PATCH] powerpc/pseries: Fix kexec regression caused by CPPR tracking The code to track the CPPR values added by commit 49bd3647134ea47420067aea8d1401e722bf2aac ("powerpc/pseries: Track previous CPPR values to correctly EOI interrupts") broke kexec on pseries because the kexec code in xics.c calls xics_set_cpu_priority() before the IPI has been EOI'ed. This wasn't a problem previously but it now triggers a BUG_ON in xics_set_cpu_priority() because os_cppr->index isn't 0. Fix this problem by setting the index on the CPPR stack to 0 before calling xics_set_cpu_priority() in xics_teardown_cpu(). Also make it clear that we only want to set the priority when there's just one CPPR value in the stack, and enforce it by updating the value of os_cppr->stack[0] rather than os_cppr->stack[os_cppr->index]. While we're at it change the BUG_ON to a WARN_ON. Reported-by: Anton Blanchard Signed-off-by: Mark Nelson Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/platforms/pseries/xics.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/platforms/pseries/xics.c b/arch/powerpc/platforms/pseries/xics.c index 1ee66db003be..f5f79196721c 100644 --- a/arch/powerpc/platforms/pseries/xics.c +++ b/arch/powerpc/platforms/pseries/xics.c @@ -784,9 +784,13 @@ static void xics_set_cpu_priority(unsigned char cppr) { struct xics_cppr *os_cppr = &__get_cpu_var(xics_cppr); - BUG_ON(os_cppr->index != 0); + /* + * we only really want to set the priority when there's + * just one cppr value on the stack + */ + WARN_ON(os_cppr->index != 0); - os_cppr->stack[os_cppr->index] = cppr; + os_cppr->stack[0] = cppr; if (firmware_has_feature(FW_FEATURE_LPAR)) lpar_cppr_info(cppr); @@ -821,8 +825,14 @@ void xics_setup_cpu(void) void xics_teardown_cpu(void) { + struct xics_cppr *os_cppr = &__get_cpu_var(xics_cppr); int cpu = smp_processor_id(); + /* + * we have to reset the cppr index to 0 because we're + * not going to return from the IPI + */ + os_cppr->index = 0; xics_set_cpu_priority(0); /* Clear any pending IPI request */ -- 2.30.2