From d55071905ee1719094c66dd3c40e2a9ef5c65eaf Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Sun, 13 Aug 2017 11:33:41 +1000 Subject: [PATCH] powerpc/64s/radix: Remove bolted-SLB address limit for per-cpu stacks Radix MMU does not take SLB or TLB interrupts when accessing kernel linear address. Remove this restriction for radix mode. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman --- arch/powerpc/kernel/setup_64.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c index af23d4b576ec..7393bac3c7f4 100644 --- a/arch/powerpc/kernel/setup_64.c +++ b/arch/powerpc/kernel/setup_64.c @@ -564,6 +564,9 @@ static __init u64 safe_stack_limit(void) /* Other BookE, we assume the first GB is bolted */ return 1ul << 30; #else + if (early_radix_enabled()) + return ULONG_MAX; + /* BookS, the first segment is bolted */ if (mmu_has_feature(MMU_FTR_1T_SEGMENT)) return 1UL << SID_SHIFT_1T; @@ -578,7 +581,8 @@ void __init irqstack_early_init(void) /* * Interrupt stacks must be in the first segment since we - * cannot afford to take SLB misses on them. + * cannot afford to take SLB misses on them. They are not + * accessed in realmode. */ for_each_possible_cpu(i) { softirq_ctx[i] = (struct thread_info *) @@ -649,8 +653,9 @@ void __init emergency_stack_init(void) * aligned. * * Since we use these as temporary stacks during secondary CPU - * bringup, we need to get at them in real mode. This means they - * must also be within the RMO region. + * bringup, machine check, system reset, and HMI, we need to get + * at them in real mode. This means they must also be within the RMO + * region. * * The IRQ stacks allocated elsewhere in this file are zeroed and * initialized in kernel/irq.c. These are initialized here in order