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authorArd Biesheuvel <ard.biesheuvel@linaro.org>2016-08-17 18:54:41 +0300
committerCatalin Marinas <catalin.marinas@arm.com>2016-08-17 19:37:37 +0300
commitbc9f3d7788a88d080a30599bde68f383daf8f8a5 (patch)
tree31bb9bddbf43207842221dff70d83a21389e4e1f /arch/arm64/kernel/sleep.S
parentbfe6c8a89e03f52bccf922f74ced8fe959e7fd36 (diff)
downloadlinux-bc9f3d7788a88d080a30599bde68f383daf8f8a5.tar.xz
arm64: kernel: avoid literal load of virtual address with MMU off
Literal loads of virtual addresses are subject to runtime relocation when CONFIG_RELOCATABLE=y, and given that the relocation routines run with the MMU and caches enabled, literal loads of relocated values performed with the MMU off are not guaranteed to return the latest value unless the memory covering the literal is cleaned to the PoC explicitly. So defer the literal load until after the MMU has been enabled, just like we do for primary_switch() and secondary_switch() in head.S. Fixes: 1e48ef7fcc37 ("arm64: add support for building vmlinux as a relocatable PIE binary") Cc: <stable@vger.kernel.org> # 4.6+ Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/kernel/sleep.S')
-rw-r--r--arch/arm64/kernel/sleep.S10
1 files changed, 9 insertions, 1 deletions
diff --git a/arch/arm64/kernel/sleep.S b/arch/arm64/kernel/sleep.S
index 9a3aec97ac09..ccf79d849e0a 100644
--- a/arch/arm64/kernel/sleep.S
+++ b/arch/arm64/kernel/sleep.S
@@ -101,12 +101,20 @@ ENTRY(cpu_resume)
bl el2_setup // if in EL2 drop to EL1 cleanly
/* enable the MMU early - so we can access sleep_save_stash by va */
adr_l lr, __enable_mmu /* __cpu_setup will return here */
- ldr x27, =_cpu_resume /* __enable_mmu will branch here */
+ adr_l x27, _resume_switched /* __enable_mmu will branch here */
adrp x25, idmap_pg_dir
adrp x26, swapper_pg_dir
b __cpu_setup
ENDPROC(cpu_resume)
+ .pushsection ".idmap.text", "ax"
+_resume_switched:
+ ldr x8, =_cpu_resume
+ br x8
+ENDPROC(_resume_switched)
+ .ltorg
+ .popsection
+
ENTRY(_cpu_resume)
mrs x1, mpidr_el1
adrp x8, mpidr_hash