From: Ard Biesheuvel <ardb@kernel.org>
To: linux-efi@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>
Cc: Ard Biesheuvel <ardb@kernel.org>,
linux-kernel@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
Arvind Sankar <nivedita@alum.mit.edu>,
Borislav Petkov <bp@suse.de>,
Colin Ian King <colin.king@canonical.com>,
Gary Lin <glin@suse.com>, Jiri Slaby <jslaby@suse.cz>,
Sergey Shatunov <me@prok.pw>, Takashi Iwai <tiwai@suse.de>
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 [thread overview]
Message-ID: <20200409130434.6736-6-ardb@kernel.org> (raw)
In-Reply-To: <20200409130434.6736-1-ardb@kernel.org>
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
next prev parent reply other threads:[~2020-04-09 13:05 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-09 13:04 [GIT PULL 0/9] EFI fixes for v5.7-rc Ard Biesheuvel
2020-04-09 13:04 ` [PATCH 1/9] efi/cper: Use scnprintf() for avoiding potential buffer overflow Ard Biesheuvel
2020-04-09 13:04 ` [PATCH 2/9] efi/libstub/x86: remove redundant assignment to pointer hdr Ard Biesheuvel
2020-04-09 13:04 ` [PATCH 3/9] efi/x86: Move efi stub globals from .bss to .data Ard Biesheuvel
2020-04-09 20:05 ` Brian Gerst
2020-04-09 20:53 ` Brian Gerst
2020-04-09 21:08 ` Arvind Sankar
2020-04-10 8:20 ` Ard Biesheuvel
2020-04-10 15:16 ` Arvind Sankar
2020-04-10 16:03 ` Ard Biesheuvel
2020-04-10 18:01 ` Arvind Sankar
2020-04-10 18:03 ` Ard Biesheuvel
2020-04-10 19:03 ` Arvind Sankar
2020-04-11 1:03 ` Arvind Sankar
2020-04-09 13:04 ` [PATCH 4/9] efi/x86: Always relocate the kernel for EFI handover entry Ard Biesheuvel
2020-04-09 13:04 ` Ard Biesheuvel [this message]
2020-04-09 13:04 ` [PATCH 6/9] Documentation: efi/x86: clarify EFI handover protocol and its requirements Ard Biesheuvel
2020-04-09 13:04 ` [PATCH 7/9] efi/libstub/file: merge filename buffers to reduce stack usage Ard Biesheuvel
2020-04-09 13:04 ` [PATCH 8/9] efi/x86: Fix the deletion of variables in mixed mode Ard Biesheuvel
2020-04-09 13:04 ` [PATCH 9/9] efi/x86: Don't remap text<->rodata gap read-only for " Ard Biesheuvel
2020-04-09 19:01 ` [GIT PULL 0/9] EFI fixes for v5.7-rc Theodore Y. Ts'o
2020-04-09 19:04 ` Ard Biesheuvel
2020-04-09 20:16 ` Theodore Y. Ts'o
2020-04-09 21:29 ` Ard Biesheuvel
2020-04-09 23:57 ` Theodore Y. Ts'o
2020-04-10 7:08 ` Ard Biesheuvel
2020-04-10 13:54 ` Dave Young
2020-04-11 19:43 ` Theodore Y. Ts'o
2020-04-12 3:51 ` Dave Young
2020-04-13 14:07 ` David Howells
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