diff options
authorPaul Mackerras <paulus@samba.org>2014-04-11 16:43:35 +1000
committerLinus Torvalds <torvalds@linux-foundation.org>2014-04-12 17:58:48 -0700
commit18aa0da33e18cb2037932f7ad5c7d51f22e012f5 (patch)
parentd7e8af1afeffb03ab250b91cd70ba8c701f0f2b7 (diff)
powerpc: Don't try to set LPCR unless we're in hypervisor mode
Commit 8f619b5429d9 ("powerpc/ppc64: Do not turn AIL (reloc-on interrupts) too early") added code to set the AIL bit in the LPCR without checking whether the kernel is running in hypervisor mode. The result is that when the kernel is running as a guest (i.e., under PowerKVM or PowerVM), the processor takes a privileged instruction interrupt at that point, causing a panic. The visible result is that the kernel hangs after printing "returning from prom_init". This fixes it by checking for hypervisor mode being available before setting LPCR. If we are not in hypervisor mode, we enable relocation-on interrupts later in pSeries_setup_arch using the H_SET_MODE hcall. Signed-off-by: Paul Mackerras <paulus@samba.org> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index 3d7a50a08f5..fbe24377eda 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -201,7 +201,8 @@ static void cpu_ready_for_interrupts(void)
get_paca()->kernel_msr = MSR_KERNEL;
/* Enable AIL if supported */
- if (cpu_has_feature(CPU_FTR_ARCH_207S)) {
+ if (cpu_has_feature(CPU_FTR_HVMODE) &&
+ cpu_has_feature(CPU_FTR_ARCH_207S)) {
unsigned long lpcr = mfspr(SPRN_LPCR);
mtspr(SPRN_LPCR, lpcr | LPCR_AIL_3);