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authorArd Biesheuvel <ard.biesheuvel@linaro.org>2016-04-18 17:09:42 +0200
committerWill Deacon <will.deacon@arm.com>2016-04-26 12:19:55 +0100
commite5ebeec879b726c755af0c1c15f3699b53268cd5 (patch)
treee33413661d6ed1909e2331a3930a20d2d66528dd
parentarm64: kernel: don't export local symbols from head.S (diff)
downloadlinux-dev-e5ebeec879b726c755af0c1c15f3699b53268cd5.tar.xz
linux-dev-e5ebeec879b726c755af0c1c15f3699b53268cd5.zip
arm64: kernel: use literal for relocated address of __secondary_switched
We can simply use a relocated 64-bit literal to store the address of __secondary_switched(), and the relocation code will ensure that it holds the correct value at secondary entry time, as long as we make sure that the literal is not dereferenced until after we have enabled the MMU. So jump via a small __secondary_switch() function covered by the ID map that performs the literal load and branch-to-register. Acked-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
-rw-r--r--arch/arm64/kernel/head.S14
1 files changed, 7 insertions, 7 deletions
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index ac27d8d937b2..f13276d4ca91 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -468,9 +468,7 @@ __mmap_switched:
str x15, [x11, x23]
b 0b
-2: adr_l x8, kimage_vaddr // make relocated kimage_vaddr
- dc cvac, x8 // value visible to secondaries
- dsb sy // with MMU off
+2:
#endif
adr_l sp, initial_sp, x4
@@ -699,12 +697,9 @@ secondary_startup:
adrp x26, swapper_pg_dir
bl __cpu_setup // initialise processor
- ldr x8, kimage_vaddr
- ldr w9, 0f
- sub x27, x8, w9, sxtw // address to jump to after enabling the MMU
+ adr_l x27, __secondary_switch // address to jump to after enabling the MMU
b __enable_mmu
ENDPROC(secondary_startup)
-0: .long (_text - TEXT_OFFSET) - __secondary_switched
__secondary_switched:
adr_l x5, vectors
@@ -806,3 +801,8 @@ __no_granule_support:
wfi
b 1b
ENDPROC(__no_granule_support)
+
+__secondary_switch:
+ ldr x8, =__secondary_switched
+ br x8
+ENDPROC(__secondary_switch)