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Message-ID: <nycvar.YSQ.7.76.1709041219510.8603@knanqh.ubzr> Date: Mon, 4 Sep 2017 12:20:47 -0400 (EDT) From: Nicolas Pitre <nicolas.pitre@...aro.org> To: Ard Biesheuvel <ard.biesheuvel@...aro.org> cc: linux-arm-kernel@...ts.infradead.org, kernel-hardening@...ts.openwall.com, Arnd Bergmann <arnd@...db.de>, Russell King <linux@...linux.org.uk>, Kees Cook <keescook@...omium.org>, Thomas Garnier <thgarnie@...gle.com>, Marc Zyngier <marc.zyngier@....com>, Mark Rutland <mark.rutland@....com>, Tony Lindgren <tony@...mide.com>, Matt Fleming <matt@...eblueprint.co.uk>, Dave Martin <dave.martin@....com> Subject: Re: [PATCH v2 09/29] ARM: sleep.S: use PC-relative insn sequence for sleep_save_sp/mpidr_hash On Sun, 3 Sep 2017, Ard Biesheuvel wrote: > Replace the open coded PC relative offset calculations with adr_l and > ldr_l invocations. Note that ALT_SMP() expects a single instruction > so move the macro invocation after it. > > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@...aro.org> Acked-by: Nicolas Pitre <nico@...aro.org> > --- > arch/arm/kernel/sleep.S | 19 +++++-------------- > 1 file changed, 5 insertions(+), 14 deletions(-) > > diff --git a/arch/arm/kernel/sleep.S b/arch/arm/kernel/sleep.S > index 0f6c1000582c..f4920b5d0fc4 100644 > --- a/arch/arm/kernel/sleep.S > +++ b/arch/arm/kernel/sleep.S > @@ -71,8 +71,9 @@ ENTRY(__cpu_suspend) > ldr r3, =sleep_save_sp > stmfd sp!, {r0, r1} @ save suspend func arg and pointer > ldr r3, [r3, #SLEEP_SAVE_SP_VIRT] > - ALT_SMP(ldr r0, =mpidr_hash) > + ALT_SMP(W(nop)) @ don't use adr_l inside ALT_SMP() > ALT_UP_B(1f) > + adr_l r0, mpidr_hash > /* This ldmia relies on the memory layout of the mpidr_hash struct */ > ldmia r0, {r1, r6-r8} @ r1 = mpidr mask (r6,r7,r8) = l[0,1,2] shifts > compute_mpidr_hash r0, r6, r7, r8, r2, r1 > @@ -137,9 +138,8 @@ ARM_BE8(setend be) @ ensure we are in BE mode > mov r1, #0 > ALT_SMP(mrc p15, 0, r0, c0, c0, 5) > ALT_UP_B(1f) > - adr r2, mpidr_hash_ptr > - ldr r3, [r2] > - add r2, r2, r3 @ r2 = struct mpidr_hash phys address > + adr_l r2, mpidr_hash @ r2 = struct mpidr_hash phys address > + > /* > * This ldmia relies on the memory layout of the mpidr_hash > * struct mpidr_hash. > @@ -147,10 +147,7 @@ ARM_BE8(setend be) @ ensure we are in BE mode > ldmia r2, { r3-r6 } @ r3 = mpidr mask (r4,r5,r6) = l[0,1,2] shifts > compute_mpidr_hash r1, r4, r5, r6, r0, r3 > 1: > - adr r0, _sleep_save_sp > - ldr r2, [r0] > - add r0, r0, r2 > - ldr r0, [r0, #SLEEP_SAVE_SP_PHYS] > + ldr_l r0, sleep_save_sp + SLEEP_SAVE_SP_PHYS > ldr r0, [r0, r1, lsl #2] > > @ load phys pgd, stack, resume fn > @@ -164,12 +161,6 @@ ENDPROC(cpu_resume) > ENDPROC(cpu_resume_arm) > #endif > > - .align 2 > -_sleep_save_sp: > - .long sleep_save_sp - . > -mpidr_hash_ptr: > - .long mpidr_hash - . @ mpidr_hash struct offset > - > .data > .type sleep_save_sp, #object > ENTRY(sleep_save_sp) > -- > 2.11.0 > >
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