From: Brian Gerst <brgerst@gmail.com>
To: linux-kernel@vger.kernel.org, x86@kernel.org
Cc: Andy Lutomirski <luto@kernel.org>, Borislav Petkov <bp@alien8.de>,
Thomas Gleixner <tglx@linutronix.de>,
"H . Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@kernel.org>,
Brian Gerst <brgerst@gmail.com>
Subject: [PATCH 2/3] x86/relocs: Make absolute percpu relocations conditional
Date: Sat, 13 Nov 2021 07:40:34 -0500 [thread overview]
Message-ID: <20211113124035.9180-3-brgerst@gmail.com> (raw)
In-Reply-To: <20211113124035.9180-1-brgerst@gmail.com>
Signed-off-by: Brian Gerst <brgerst@gmail.com>
---
arch/x86/Kconfig | 4 ++++
arch/x86/boot/compressed/Makefile | 3 ++-
arch/x86/tools/relocs.c | 4 ++--
arch/x86/tools/relocs.h | 4 ++--
arch/x86/tools/relocs_common.c | 11 ++++++++---
init/Kconfig | 1 -
6 files changed, 18 insertions(+), 9 deletions(-)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 8268910e09cd..832a6626df72 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -402,6 +402,10 @@ config STACKPROTECTOR_FIXED
depends on X86_64 && STACKPROTECTOR
default y if !$(cc-option,-mstack-protector-guard-reg=gs)
+config X86_ABSOLUTE_PERCPU
+ def_bool X86_64 && SMP
+ select KALLSYMS_ABSOLUTE_PERCPU
+
menu "Processor type and features"
config SMP
diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index 431bf7f846c3..ff493f262f2a 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -112,8 +112,9 @@ $(obj)/vmlinux.bin: vmlinux FORCE
targets += $(patsubst $(obj)/%,%,$(vmlinux-objs-y)) vmlinux.bin.all vmlinux.relocs
CMD_RELOCS = arch/x86/tools/relocs
+relocs-flags-$(CONFIG_X86_ABSOLUTE_PERCPU) += --absolute-percpu
quiet_cmd_relocs = RELOCS $@
- cmd_relocs = $(CMD_RELOCS) $< > $@;$(CMD_RELOCS) --abs-relocs $<
+ cmd_relocs = $(CMD_RELOCS) $(relocs-flags-y) $< > $@;$(CMD_RELOCS) --abs-relocs $<
$(obj)/vmlinux.relocs: vmlinux FORCE
$(call if_changed,relocs)
diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c
index 3f5d39768287..bad375444cee 100644
--- a/arch/x86/tools/relocs.c
+++ b/arch/x86/tools/relocs.c
@@ -1166,7 +1166,7 @@ static void print_reloc_info(void)
void process(FILE *fp, int use_real_mode, int as_text,
int show_absolute_syms, int show_absolute_relocs,
- int show_reloc_info)
+ int show_reloc_info, int absolute_percpu)
{
regex_init(use_real_mode);
read_ehdr(fp);
@@ -1174,7 +1174,7 @@ void process(FILE *fp, int use_real_mode, int as_text,
read_strtabs(fp);
read_symtabs(fp);
read_relocs(fp);
- if (ELF_BITS == 64)
+ if (ELF_BITS == 64 && absolute_percpu)
percpu_init();
if (show_absolute_syms) {
print_absolute_symbols();
diff --git a/arch/x86/tools/relocs.h b/arch/x86/tools/relocs.h
index 4c49c82446eb..dcf323f6102f 100644
--- a/arch/x86/tools/relocs.h
+++ b/arch/x86/tools/relocs.h
@@ -32,8 +32,8 @@ enum symtype {
void process_32(FILE *fp, int use_real_mode, int as_text,
int show_absolute_syms, int show_absolute_relocs,
- int show_reloc_info);
+ int show_reloc_info, int absolute_percpu);
void process_64(FILE *fp, int use_real_mode, int as_text,
int show_absolute_syms, int show_absolute_relocs,
- int show_reloc_info);
+ int show_reloc_info, int absolute_percpu);
#endif /* RELOCS_H */
diff --git a/arch/x86/tools/relocs_common.c b/arch/x86/tools/relocs_common.c
index 6634352a20bc..aa5fdea1e87a 100644
--- a/arch/x86/tools/relocs_common.c
+++ b/arch/x86/tools/relocs_common.c
@@ -19,7 +19,7 @@ static void usage(void)
int main(int argc, char **argv)
{
int show_absolute_syms, show_absolute_relocs, show_reloc_info;
- int as_text, use_real_mode;
+ int as_text, use_real_mode, absolute_percpu;
const char *fname;
FILE *fp;
int i;
@@ -30,6 +30,7 @@ int main(int argc, char **argv)
show_reloc_info = 0;
as_text = 0;
use_real_mode = 0;
+ absolute_percpu = 0;
fname = NULL;
for (i = 1; i < argc; i++) {
char *arg = argv[i];
@@ -54,6 +55,10 @@ int main(int argc, char **argv)
use_real_mode = 1;
continue;
}
+ if (strcmp(arg, "--absolute-percpu") == 0) {
+ absolute_percpu = 1;
+ continue;
+ }
}
else if (!fname) {
fname = arg;
@@ -75,11 +80,11 @@ int main(int argc, char **argv)
if (e_ident[EI_CLASS] == ELFCLASS64)
process_64(fp, use_real_mode, as_text,
show_absolute_syms, show_absolute_relocs,
- show_reloc_info);
+ show_reloc_info, absolute_percpu);
else
process_32(fp, use_real_mode, as_text,
show_absolute_syms, show_absolute_relocs,
- show_reloc_info);
+ show_reloc_info, absolute_percpu);
fclose(fp);
return 0;
}
diff --git a/init/Kconfig b/init/Kconfig
index 11f8a845f259..f8da0e5b7663 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1716,7 +1716,6 @@ config KALLSYMS_ALL
config KALLSYMS_ABSOLUTE_PERCPU
bool
depends on KALLSYMS
- default X86_64 && SMP
config KALLSYMS_BASE_RELATIVE
bool
--
2.31.1
next prev parent reply other threads:[~2021-11-13 12:42 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-13 12:40 [PATCH 0/3] x86-64: Stack protector and percpu improvements Brian Gerst
2021-11-13 12:40 ` [PATCH 1/3] x86-64: Use per-cpu stack canary if supported by compiler Brian Gerst
2021-11-13 12:40 ` Brian Gerst [this message]
2021-11-13 12:40 ` [PATCH 3/3] x86_64: Use relative per-cpu offsets Brian Gerst
2021-11-14 1:18 ` Andy Lutomirski
2021-11-14 4:24 ` H. Peter Anvin
2021-11-14 4:54 ` Brian Gerst
2021-11-14 11:03 ` Peter Zijlstra
2021-11-14 18:29 ` Brian Gerst
2021-11-15 18:12 ` Andy Lutomirski
2021-11-15 20:44 ` Peter Zijlstra
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