From a94691680bace7e1404e4f235badb74e30467e86 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Thu, 9 Apr 2020 15:04:30 +0200 Subject: 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 Tested-by: Arnd Bergmann Signed-off-by: Ard Biesheuvel Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20200409130434.6736-6-ardb@kernel.org --- arch/arm/boot/compressed/head.S | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'arch/arm') 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 -- cgit v1.2.3