Messages in this thread Patch in this message | | | From | Ard Biesheuvel <> | Subject | [PATCH 5/9] efi/arm: Deal with ADR going out of range in efi_enter_kernel() | Date | Thu, 9 Apr 2020 15:04:30 +0200 |
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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> --- arch/arm/boot/compressed/head.S | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S index 04f77214f050..61e6ee3ba75f 100644 --- a/arch/arm/boot/compressed/head.S +++ b/arch/arm/boot/compressed/head.S @@ -1454,7 +1454,8 @@ 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 -- 2.17.1
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