From 18aa0da33e18cb2037932f7ad5c7d51f22e012f5 Mon Sep 17 00:00:00 2001 From: Paul Mackerras Date: Fri, 11 Apr 2014 16:43:35 +1000 Subject: [PATCH] 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 Acked-by: Benjamin Herrenschmidt Signed-off-by: Linus Torvalds --- arch/powerpc/kernel/setup_64.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c index 3d7a50a08f5e..fbe24377eda3 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); }