From baa49d81a94bb4170e7f2f4d97016772117d0f60 Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Sun, 27 Nov 2022 22:49:30 +1000 Subject: [PATCH] powerpc/pseries: hvcall stack frame overhead This call may use the min size stack frame. The scratch space used is in the caller's parameter area frame, not this function's frame. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20221127124942.1665522-6-npiggin@gmail.com --- arch/powerpc/platforms/pseries/hvCall.S | 38 +++++++++++++------------ 1 file changed, 20 insertions(+), 18 deletions(-) diff --git a/arch/powerpc/platforms/pseries/hvCall.S b/arch/powerpc/platforms/pseries/hvCall.S index 762eb15d3bd426..783c16ad648b86 100644 --- a/arch/powerpc/platforms/pseries/hvCall.S +++ b/arch/powerpc/platforms/pseries/hvCall.S @@ -27,7 +27,9 @@ hcall_tracepoint_refcount: /* * precall must preserve all registers. use unused STK_PARAM() - * areas to save snapshots and opcode. + * areas to save snapshots and opcode. STK_PARAM() in the caller's + * frame will be available even on ELFv2 because these are all + * variadic functions. */ #define HCALL_INST_PRECALL(FIRST_REG) \ mflr r0; \ @@ -41,29 +43,29 @@ hcall_tracepoint_refcount: std r10,STK_PARAM(R10)(r1); \ std r0,16(r1); \ addi r4,r1,STK_PARAM(FIRST_REG); \ - stdu r1,-STACK_FRAME_OVERHEAD(r1); \ + stdu r1,-STACK_FRAME_MIN_SIZE(r1); \ bl __trace_hcall_entry; \ - ld r3,STACK_FRAME_OVERHEAD+STK_PARAM(R3)(r1); \ - ld r4,STACK_FRAME_OVERHEAD+STK_PARAM(R4)(r1); \ - ld r5,STACK_FRAME_OVERHEAD+STK_PARAM(R5)(r1); \ - ld r6,STACK_FRAME_OVERHEAD+STK_PARAM(R6)(r1); \ - ld r7,STACK_FRAME_OVERHEAD+STK_PARAM(R7)(r1); \ - ld r8,STACK_FRAME_OVERHEAD+STK_PARAM(R8)(r1); \ - ld r9,STACK_FRAME_OVERHEAD+STK_PARAM(R9)(r1); \ - ld r10,STACK_FRAME_OVERHEAD+STK_PARAM(R10)(r1) + ld r3,STACK_FRAME_MIN_SIZE+STK_PARAM(R3)(r1); \ + ld r4,STACK_FRAME_MIN_SIZE+STK_PARAM(R4)(r1); \ + ld r5,STACK_FRAME_MIN_SIZE+STK_PARAM(R5)(r1); \ + ld r6,STACK_FRAME_MIN_SIZE+STK_PARAM(R6)(r1); \ + ld r7,STACK_FRAME_MIN_SIZE+STK_PARAM(R7)(r1); \ + ld r8,STACK_FRAME_MIN_SIZE+STK_PARAM(R8)(r1); \ + ld r9,STACK_FRAME_MIN_SIZE+STK_PARAM(R9)(r1); \ + ld r10,STACK_FRAME_MIN_SIZE+STK_PARAM(R10)(r1) /* * postcall is performed immediately before function return which * allows liberal use of volatile registers. */ #define __HCALL_INST_POSTCALL \ - ld r0,STACK_FRAME_OVERHEAD+STK_PARAM(R3)(r1); \ - std r3,STACK_FRAME_OVERHEAD+STK_PARAM(R3)(r1); \ + ld r0,STACK_FRAME_MIN_SIZE+STK_PARAM(R3)(r1); \ + std r3,STACK_FRAME_MIN_SIZE+STK_PARAM(R3)(r1); \ mr r4,r3; \ mr r3,r0; \ bl __trace_hcall_exit; \ - ld r0,STACK_FRAME_OVERHEAD+16(r1); \ - addi r1,r1,STACK_FRAME_OVERHEAD; \ + ld r0,STACK_FRAME_MIN_SIZE+16(r1); \ + addi r1,r1,STACK_FRAME_MIN_SIZE; \ ld r3,STK_PARAM(R3)(r1); \ mtlr r0 @@ -303,14 +305,14 @@ plpar_hcall9_trace: mr r7,r8 mr r8,r9 mr r9,r10 - ld r10,STACK_FRAME_OVERHEAD+STK_PARAM(R11)(r1) - ld r11,STACK_FRAME_OVERHEAD+STK_PARAM(R12)(r1) - ld r12,STACK_FRAME_OVERHEAD+STK_PARAM(R13)(r1) + ld r10,STACK_FRAME_MIN_SIZE+STK_PARAM(R11)(r1) + ld r11,STACK_FRAME_MIN_SIZE+STK_PARAM(R12)(r1) + ld r12,STACK_FRAME_MIN_SIZE+STK_PARAM(R13)(r1) HVSC mr r0,r12 - ld r12,STACK_FRAME_OVERHEAD+STK_PARAM(R4)(r1) + ld r12,STACK_FRAME_MIN_SIZE+STK_PARAM(R4)(r1) std r4,0(r12) std r5,8(r12) std r6,16(r12)