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Message-Id: <20170814125411.22604-21-ard.biesheuvel@linaro.org>
Date: Mon, 14 Aug 2017 13:54:01 +0100
From: Ard Biesheuvel <ard.biesheuvel@...aro.org>
To: kernel-hardening@...ts.openwall.com
Cc: linux-arm-kernel@...ts.infradead.org,
Ard Biesheuvel <ard.biesheuvel@...aro.org>,
Arnd Bergmann <arnd@...db.de>,
Nicolas Pitre <nico@...aro.org>,
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: [PATCH 20/30] ARM: kernel: use PC relative symbol references in suspend/resume code
Replace some unnecessary absolute references with relative ones. Also,
to prepare for runtime relocation, which occurs with the caches on,
defer taking the absolute address of cpu_resume_after_mmu() until after
the MMU is enabled.
Cc: Russell King <linux@...linux.org.uk>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@...aro.org>
---
arch/arm/kernel/sleep.S | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)
diff --git a/arch/arm/kernel/sleep.S b/arch/arm/kernel/sleep.S
index 3026b119d3ff..9efd1c7d3552 100644
--- a/arch/arm/kernel/sleep.S
+++ b/arch/arm/kernel/sleep.S
@@ -60,18 +60,17 @@
ENTRY(__cpu_suspend)
stmfd sp!, {r4 - r11, lr}
#ifdef MULTI_CPU
- ldr r10, =processor
- ldr r4, [r10, #CPU_SLEEP_SIZE] @ size of CPU sleep state
+ ldr_l r4, processor + CPU_SLEEP_SIZE @ size of CPU sleep state
#else
- ldr r4, =cpu_suspend_size
+ adr_l r4, cpu_suspend_size
#endif
mov r5, sp @ current virtual SP
add r4, r4, #12 @ Space for pgd, virt sp, phys resume fn
sub sp, sp, r4 @ allocate CPU state on stack
- ldr r3, =sleep_save_sp
+ adr_l 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(adr_l r0, mpidr_hash)
ALT_UP_B(1f)
/* 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
@@ -100,13 +99,13 @@ ENDPROC(cpu_suspend_abort)
.align 5
.pushsection .idmap.text,"ax"
ENTRY(cpu_resume_mmu)
- ldr r3, =cpu_resume_after_mmu
instr_sync
mcr p15, 0, r0, c1, c0, 0 @ turn on MMU, I-cache, etc
mrc p15, 0, r0, c0, c0, 0 @ read id reg
instr_sync
mov r0, r0
mov r0, r0
+ ldr r3, =cpu_resume_after_mmu
ret r3 @ jump to virtual address
ENDPROC(cpu_resume_mmu)
.popsection
--
2.11.0
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