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authorRafael Ávila de Espíndola <rafael@espindo.la>2018-12-19 11:01:43 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-04-05 22:31:40 +0200
commit1d0961c1e0e61ebeeeaaad6eb1777c425d56a5c4 (patch)
parentd2a1b60a109be0a938d7ddcc4d10da0f9e94e8e3 (diff)
x86/build: Mark per-CPU symbols as absolute explicitly for LLD
[ Upstream commit d071ae09a4a1414c1433d5ae9908959a7325b0ad ] Accessing per-CPU variables is done by finding the offset of the variable in the per-CPU block and adding it to the address of the respective CPU's block. Section 3.10.8 of ld.bfd's documentation states: For expressions involving numbers, relative addresses and absolute addresses, ld follows these rules to evaluate terms: Other binary operations, that is, between two relative addresses not in the same section, or between a relative address and an absolute address, first convert any non-absolute term to an absolute address before applying the operator." Note that LLVM's linker does not adhere to the GNU ld's implementation and as such requires implicitly-absolute terms to be explicitly marked as absolute in the linker script. If not, it fails currently with: ld.lld: error: ./arch/x86/kernel/vmlinux.lds:153: at least one side of the expression must be absolute ld.lld: error: ./arch/x86/kernel/vmlinux.lds:154: at least one side of the expression must be absolute Makefile:1040: recipe for target 'vmlinux' failed This is not a functional change for ld.bfd which converts the term to an absolute symbol anyways as specified above. Based on a previous submission by Tri Vo <trong@android.com>. Reported-by: Dmitry Golovin <dima@golovin.in> Signed-off-by: Rafael Ávila de Espíndola <rafael@espindo.la> [ Update commit message per Boris' and Michael's suggestions. ] Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> [ Massage commit message more, fix typos. ] Signed-off-by: Borislav Petkov <bp@suse.de> Tested-by: Dmitry Golovin <dima@golovin.in> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Brijesh Singh <brijesh.singh@amd.com> Cc: Cao Jin <caoj.fnst@cn.fujitsu.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Joerg Roedel <jroedel@suse.de> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tri Vo <trong@android.com> Cc: dima@golovin.in Cc: morbo@google.com Cc: x86-ml <x86@kernel.org> Link: https://lkml.kernel.org/r/20181219190145.252035-1-ndesaulniers@google.com Signed-off-by: Sasha Levin <sashal@kernel.org>
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index b854ebf5851b..2384a2ae5ec3 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -390,7 +390,7 @@ SECTIONS
* Per-cpu symbols which need to be offset from __per_cpu_load
* for the boot processor.
-#define INIT_PER_CPU(x) init_per_cpu__##x = x + __per_cpu_load
+#define INIT_PER_CPU(x) init_per_cpu__##x = ABSOLUTE(x) + __per_cpu_load