Use the convenience macros for saving/clearing/restoring gprs in keeping
with syscall calling conventions. The plural variants of these macros
can store a range of registers for concision.
This works well when the save-to-stack logic is simple (a gpr is saved
to its corresponding offset in the struct pt_regs on the stack).
Wherever a different gpr is storing the initial value of another gpr at
the interrupt location, care must be taken to issue the correct save
instruction and so the macros are not applied in neighbouring stores.
Signed-off-by: Rohan McLure <rmcl...@linux.ibm.com>
---
V1 -> V2: Update summary
---
arch/powerpc/kernel/interrupt_64.S | 29 ++++++----------------------
1 file changed, 6 insertions(+), 23 deletions(-)
diff --git a/arch/powerpc/kernel/interrupt_64.S
b/arch/powerpc/kernel/interrupt_64.S
index 34167cfa5d60..efaf162fa772 100644
--- a/arch/powerpc/kernel/interrupt_64.S
+++ b/arch/powerpc/kernel/interrupt_64.S
@@ -71,12 +71,7 @@ _ASM_NOKPROBE_SYMBOL(system_call_vectored_\name)
mfcr r12
li r11,0
/* Save syscall parameters in r3-r8 */
- std r3,GPR3(r1)
- std r4,GPR4(r1)
- std r5,GPR5(r1)
- std r6,GPR6(r1)
- std r7,GPR7(r1)
- std r8,GPR8(r1)
+ SAVE_GPRS(3, 8, r1)
/* Zero r9-r12, this should only be required when restoring all GPRs */
std r11,GPR9(r1)
std r11,GPR10(r1)
@@ -156,17 +151,10 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
/* Could zero these as per ABI, but we may consider a stricter ABI
* which preserves these if libc implementations can benefit, so
* restore them for now until further measurement is done. */
- ld r0,GPR0(r1)
- ld r4,GPR4(r1)
- ld r5,GPR5(r1)
- ld r6,GPR6(r1)
- ld r7,GPR7(r1)
- ld r8,GPR8(r1)
+ REST_GPR(0, r1)
+ REST_GPRS(4, 8, r1)
/* Zero volatile regs that may contain sensitive kernel data */
- li r9,0
- li r10,0
- li r11,0
- li r12,0
+ NULLIFY_GPRS(9, 12)
mtspr SPRN_XER,r0
/*
@@ -188,7 +176,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
ld r4,_LINK(r1)
ld r5,_XER(r1)
- ld r0,GPR0(r1)
+ REST_GPR(0, r1)
mtcr r2
mtctr r3
mtlr r4
@@ -256,12 +244,7 @@ END_BTB_FLUSH_SECTION
mfcr r12
li r11,0
/* Save syscall parameters in r3-r8 */
- std r3,GPR3(r1)
- std r4,GPR4(r1)
- std r5,GPR5(r1)
- std r6,GPR6(r1)
- std r7,GPR7(r1)
- std r8,GPR8(r1)
+ SAVE_GPRS(3, 8, r1)
/* Zero r9-r12, this should only be required when restoring all GPRs */
std r11,GPR9(r1)
std r11,GPR10(r1)
--
2.34.1
