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powerpc/64s/radix: Remove bolted-SLB address limit for per-cpu stacks

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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 <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Nicholas Piggin 2017-08-13 11:33:41 +10:00 committed by Michael Ellerman
parent 76b42e28be
commit d55071905e
1 changed files with 8 additions and 3 deletions
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11
arch/powerpc/kernel/setup_64.c
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@ -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