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 <npig...@gmail.com> --- arch/powerpc/kernel/exceptions-64s.S | 34 +++++++++++++++++++++++++--- 1 file changed, 31 insertions(+), 3 deletions(-) diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index 1bccc869ebd3..07e00f690730 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -492,10 +492,33 @@ DEFINE_FIXED_SYMBOL(\name\()_common_virt) .endif /* IVIRT */ .endm +#define LOAD_IMM(reg, expr) \ + lis reg,(expr)@highest; \ + ori reg,reg,(expr)@higher; \ + rldicr reg,reg,32,31; \ + oris reg,reg,(expr)@__AS_ATHIGH; \ + ori reg,reg,(expr)@l + .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) + cmpd 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 @@ -526,7 +549,7 @@ DEFINE_FIXED_SYMBOL(\name\()_common_virt) .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 */ @@ -2771,7 +2794,8 @@ 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 @@ -2930,6 +2954,10 @@ 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 -- 2.23.0