Le 25/07/2022 à 08:31, Rohan McLure a écrit : > 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.
Some cleaning could also be done in entry_32.S > > 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)
