| Message ID | 1472828533-28197-3-git-send-email-catalin.marinas@arm.com |
|---|---|
| State | New |
| Headers | show |
Hi Catalin, On Fri, Sep 02, 2016 at 04:02:08PM +0100, Catalin Marinas wrote: > This patch takes the errata workaround code out of cpu_do_switch_mm into > a dedicated post_ttbr0_update_workaround macro which will be reused in a > subsequent patch. > +/* > + * Errata workaround post TTBR0_EL1 update. > + */ > + .macro post_ttbr0_update_workaround, ret = 0 > +alternative_if_not ARM64_WORKAROUND_CAVIUM_27456 > + .if \ret > + ret > + .endif > + nop > + nop > + nop > +alternative_else > + ic iallu > + dsb nsh > + isb > + .if \ret > + ret > + .endif > +alternative_endif > + .endm IMO, the ret parameter makes the callers harder to read. Can we leave the ret up to the caller and suffer the marginal penalty of a few nops in a slow(ish) path? We can get rid of them in the !CONFIG_CAVIUM_ERRATUM_27456 case with a simple ifdef: .macro post_ttbr0_update_workaround #ifdef CONFIG_CAVIUM_ERRATUM_27456 alternative_if_not ARM64_WORKAROUND_CAVIUM_27456 nop nop nop alternative_else ic iallu dsb nsh isb alternative_endif #endif .endm > + > #endif /* __ASM_ASSEMBLER_H */ > diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S > index 5bb61de23201..9359659f2559 100644 > --- a/arch/arm64/mm/proc.S > +++ b/arch/arm64/mm/proc.S > @@ -125,17 +125,7 @@ ENTRY(cpu_do_switch_mm) > bfi x0, x1, #48, #16 // set the ASID > msr ttbr0_el1, x0 // set TTBR0 > isb > -alternative_if_not ARM64_WORKAROUND_CAVIUM_27456 > - ret > - nop > - nop > - nop > -alternative_else > - ic iallu > - dsb nsh > - isb > - ret > -alternative_endif > + post_ttbr0_update_workaround ret = 1 + ret Thanks, Mark, _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h index d5025c69ca81..b16bbf1fb786 100644 --- a/arch/arm64/include/asm/assembler.h +++ b/arch/arm64/include/asm/assembler.h @@ -350,4 +350,25 @@ alternative_endif movk \reg, :abs_g0_nc:\val .endm +/* + * Errata workaround post TTBR0_EL1 update. + */ + .macro post_ttbr0_update_workaround, ret = 0 +alternative_if_not ARM64_WORKAROUND_CAVIUM_27456 + .if \ret + ret + .endif + nop + nop + nop +alternative_else + ic iallu + dsb nsh + isb + .if \ret + ret + .endif +alternative_endif + .endm + #endif /* __ASM_ASSEMBLER_H */ diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S index 5bb61de23201..9359659f2559 100644 --- a/arch/arm64/mm/proc.S +++ b/arch/arm64/mm/proc.S @@ -125,17 +125,7 @@ ENTRY(cpu_do_switch_mm) bfi x0, x1, #48, #16 // set the ASID msr ttbr0_el1, x0 // set TTBR0 isb -alternative_if_not ARM64_WORKAROUND_CAVIUM_27456 - ret - nop - nop - nop -alternative_else - ic iallu - dsb nsh - isb - ret -alternative_endif + post_ttbr0_update_workaround ret = 1 ENDPROC(cpu_do_switch_mm) .pushsection ".idmap.text", "ax"
This patch takes the errata workaround code out of cpu_do_switch_mm into a dedicated post_ttbr0_update_workaround macro which will be reused in a subsequent patch. Cc: Will Deacon <will.deacon@arm.com> Cc: James Morse <james.morse@arm.com> Cc: Kees Cook <keescook@chromium.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> --- arch/arm64/include/asm/assembler.h | 21 +++++++++++++++++++++ arch/arm64/mm/proc.S | 12 +----------- 2 files changed, 22 insertions(+), 11 deletions(-) _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel