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authorArd Biesheuvel <ardb@kernel.org>2020-04-09 15:04:30 +0200
committerIngo Molnar <mingo@kernel.org>2020-04-14 08:32:14 +0200
commita94691680bace7e1404e4f235badb74e30467e86 (patch)
tree349cc33f1ac553ff4ecbd49fce8f719c6ee91c2a /arch/arm
parent21cb9b414301c76f77f70d990a784ad6360e5a20 (diff)
efi/arm: Deal with ADR going out of range in efi_enter_kernel()
Commit 0698fac4ac2a ("efi/arm: Clean EFI stub exit code from cache instead of avoiding it") introduced a PC-relative reference to 'call_cache_fn' into efi_enter_kernel(), which lives way at the end of head.S. In some cases, the ARM version of the ADR instruction does not have sufficient range, resulting in a build error: arch/arm/boot/compressed/head.S:1453: Error: invalid constant (fffffffffffffbe4) after fixup ARM defines an alternative with a wider range, called ADRL, but this does not exist for Thumb-2. At the same time, the ADR instruction in Thumb-2 has a wider range, and so it does not suffer from the same issue. So let's switch to ADRL for ARM builds, and keep the ADR for Thumb-2 builds. Reported-by: Arnd Bergmann <arnd@arndb.de> Tested-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20200409130434.6736-6-ardb@kernel.org
Diffstat (limited to 'arch/arm')
-rw-r--r--arch/arm/boot/compressed/head.S3
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S
index cabdd8f4a248..e8e1c866e413 100644
--- a/arch/arm/boot/compressed/head.S
+++ b/arch/arm/boot/compressed/head.S
@@ -1450,7 +1450,8 @@ ENTRY(efi_enter_kernel)
@ running beyond the PoU, and so calling cache_off below from
@ inside the PE/COFF loader allocated region is unsafe unless
@ we explicitly clean it to the PoC.
- adr r0, call_cache_fn @ region of code we will
+ ARM( adrl r0, call_cache_fn )
+ THUMB( adr r0, call_cache_fn ) @ region of code we will
adr r1, 0f @ run with MMU off
bl cache_clean_flush
bl cache_off