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| author |   Nicholas Piggin <npiggin@gmail.com> | 2020-06-11 18:12:02 +1000 |
|---|---|---|
| committer |   Michael Ellerman <mpe@ellerman.id.au> | 2020-07-22 23:00:23 +1000 |
| commit | b2dc2977cba48990df45e0a96150663d4f342700 (patch) | |
| tree | a09c1b479ed48c24cca0c217c080ec5494c2887c /arch/powerpc | |
| parent | Linux 5.8-rc2 (diff) | |
| download | linux-dev-b2dc2977cba48990df45e0a96150663d4f342700.tar.xz linux-dev-b2dc2977cba48990df45e0a96150663d4f342700.zip | |
powerpc/64s/exception: treat NIA below __end_interrupts as soft-masked
The scv instruction causes an interrupt which can enter the kernel with
MSR[EE]=1, thus allowing interrupts to hit at any time. These must not
be taken as normal interrupts, because they come from MSR[PR]=0 context,
and yet the kernel stack is not yet set up and r13 is not set to the
PACA).
Treat this as a soft-masked interrupt regardless of the soft masked
state. This does not affect behaviour yet, because currently all
interrupts are taken with MSR[EE]=0.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200611081203.995112-2-npiggin@gmail.com
Diffstat (limited to 'arch/powerpc')
| -rw-r--r-- | arch/powerpc/kernel/exceptions-64s.S | 27 |
1 files changed, 24 insertions, 3 deletions
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index fa080694e581..f15307c50bc1 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -508,8 +508,24 @@ DEFINE_FIXED_SYMBOL(\name\()_common_real) .macro __GEN_COMMON_BODY name .if IMASK + .if ! ISTACK + .error "No support for masked interrupt to use custom stack" + .endif + + /* If coming from user, skip soft-mask tests. */ + andi. r10,r12,MSR_PR + bne 2f + + /* Kernel code running below __end_interrupts is implicitly + * soft-masked */ + LOAD_HANDLER(r10, __end_interrupts) + cmpld r11,r10 + li r10,IMASK + blt- 1f + + /* Test the soft mask state against our interrupt's bit */ lbz r10,PACAIRQSOFTMASK(r13) - andi. r10,r10,IMASK +1: andi. r10,r10,IMASK /* Associate vector numbers with bits in paca->irq_happened */ .if IVEC == 0x500 || IVEC == 0xea0 li r10,PACA_IRQ_EE @@ -540,7 +556,7 @@ DEFINE_FIXED_SYMBOL(\name\()_common_real) .if ISTACK andi. r10,r12,MSR_PR /* See if coming from user */ - mr r10,r1 /* Save r1 */ +2: mr r10,r1 /* Save r1 */ subi r1,r1,INT_FRAME_SIZE /* alloc frame on kernel stack */ beq- 100f ld r1,PACAKSAVE(r13) /* kernel stack to use */ @@ -2838,7 +2854,8 @@ masked_interrupt: ld r10,PACA_EXGEN+EX_R10(r13) ld r11,PACA_EXGEN+EX_R11(r13) ld r12,PACA_EXGEN+EX_R12(r13) - /* returns to kernel where r13 must be set up, so don't restore it */ + ld r13,PACA_EXGEN+EX_R13(r13) + /* May return to masked low address where r13 is not set up */ .if \hsrr HRFI_TO_KERNEL .else @@ -2997,6 +3014,10 @@ EXC_COMMON_BEGIN(ppc64_runlatch_on_trampoline) USE_FIXED_SECTION(virt_trampolines) /* + * All code below __end_interrupts is treated as soft-masked. If + * any code runs here with MSR[EE]=1, it must then cope with pending + * soft interrupt being raised (i.e., by ensuring it is replayed). + * * The __end_interrupts marker must be past the out-of-line (OOL) * handlers, so that they are copied to real address 0x100 when running * a relocatable kernel. This ensures they can be reached from the short |