From: Fangrui Song <maskray@google.com>
To: x86@kernel.org, Arvind Sankar <nivedita@alum.mit.edu>,
linux-efi@vger.kernel.org
Cc: clang-built-linux@googlegroups.com,
Nick Desaulniers <ndesaulniers@google.com>,
Ard Biesheuvel <ardb@kernel.org>,
Fangrui Song <maskray@google.com>,
kbuild test robot <lkp@intel.com>
Subject: [PATCH] x86/boot: Discard .discard.unreachable for arch/x86/boot/compressed/vmlinux
Date: Wed, 20 May 2020 11:20:10 -0700 [thread overview]
Message-ID: <20200520182010.242489-1-maskray@google.com> (raw)
In the latest efi tree, ce5e3f909fc0ed67e58367b9c56a54c20a51080b
"efi/printf: Add 64-bit and 8-bit integer support",
arch/x86/boot/compressed/vmlinux may have an undesired
.discard.unreachable section from drivers/firmware/efi/libstub/vsprintf.stub.o
.discard.unreachable contains an R_X86_64_PC32 relocation, which will be
warned by LLD: a non-SHF_ALLOC section (.discard.unreachable) is not
part of the memory image, thus conceptually the distance between a
non-SHF_ALLOC and a SHF_ALLOC is not a constant which can be resolved at
link time.
% ld.lld -m elf_x86_64 -T arch/x86/boot/compressed/vmlinux.lds ... -o arch/x86/boot/compressed/vmlinux
ld.lld: warning: vsprintf.c:(.discard.unreachable+0x0): has non-ABS relocation R_X86_64_PC32 against symbol ''
Reuse the DISCARDS macro which includes .discard.* to drop .discard.unreachable
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Fangrui Song <maskray@google.com>
---
arch/x86/boot/compressed/vmlinux.lds.S | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/x86/boot/compressed/vmlinux.lds.S b/arch/x86/boot/compressed/vmlinux.lds.S
index 0dc5c2b9614b..8f1025d1f681 100644
--- a/arch/x86/boot/compressed/vmlinux.lds.S
+++ b/arch/x86/boot/compressed/vmlinux.lds.S
@@ -74,4 +74,6 @@ SECTIONS
#endif
. = ALIGN(PAGE_SIZE); /* keep ZO size page aligned */
_end = .;
+
+ DISCARDS
}
--
2.26.2.761.g0e0b3e54be-goog
next reply other threads:[~2020-05-20 18:21 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-20 18:20 Fangrui Song [this message]
2020-05-20 19:19 ` [PATCH] x86/boot: Discard .discard.unreachable for arch/x86/boot/compressed/vmlinux Arvind Sankar
2020-05-22 2:42 ` Kees Cook
2020-05-22 6:51 ` Sedat Dilek
2020-05-22 15:54 ` Ard Biesheuvel
2020-05-22 15:57 ` Sedat Dilek
2020-05-22 15:59 ` Ard Biesheuvel
2020-05-22 12:40 ` [tip: x86/build] " tip-bot2 for Fangrui Song
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