6.10-stable review patch. If anyone has any objections, please let me know.
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From: Masahiro Yamada masahiroy@kernel.org
[ Upstream commit c442db3f49f27e5a60a641b2ac9a3c6320796ed6 ]
This reimplements commit 951bcae6c5a0 ("kallsyms: Avoid weak references for kallsyms symbols") because I am not a big fan of PROVIDE().
As an alternative solution, this commit prepends one more kallsyms step.
KSYMS .tmp_vmlinux.kallsyms0.S # added AS .tmp_vmlinux.kallsyms0.o # added LD .tmp_vmlinux.btf BTF .btf.vmlinux.bin.o LD .tmp_vmlinux.kallsyms1 NM .tmp_vmlinux.kallsyms1.syms KSYMS .tmp_vmlinux.kallsyms1.S AS .tmp_vmlinux.kallsyms1.o LD .tmp_vmlinux.kallsyms2 NM .tmp_vmlinux.kallsyms2.syms KSYMS .tmp_vmlinux.kallsyms2.S AS .tmp_vmlinux.kallsyms2.o LD vmlinux
Step 0 takes /dev/null as input, and generates .tmp_vmlinux.kallsyms0.o, which has a valid kallsyms format with the empty symbol list, and can be linked to vmlinux. Since it is really small, the added compile-time cost is negligible.
Signed-off-by: Masahiro Yamada masahiroy@kernel.org Acked-by: Ard Biesheuvel ardb@kernel.org Reviewed-by: Nicolas Schier nicolas@fjasle.eu Stable-dep-of: 020925ce9299 ("kallsyms: Do not cleanup .llvm.<hash> suffix before sorting symbols") Signed-off-by: Sasha Levin sashal@kernel.org --- include/asm-generic/vmlinux.lds.h | 19 ------------------- kernel/kallsyms_internal.h | 5 ----- scripts/kallsyms.c | 6 ------ scripts/link-vmlinux.sh | 9 +++++++-- 4 files changed, 7 insertions(+), 32 deletions(-)
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index 70bf1004076b2..f00a8e18f389f 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -451,30 +451,11 @@ #endif #endif
-/* - * Some symbol definitions will not exist yet during the first pass of the - * link, but are guaranteed to exist in the final link. Provide preliminary - * definitions that will be superseded in the final link to avoid having to - * rely on weak external linkage, which requires a GOT when used in position - * independent code. - */ -#define PRELIMINARY_SYMBOL_DEFINITIONS \ - PROVIDE(kallsyms_addresses = .); \ - PROVIDE(kallsyms_offsets = .); \ - PROVIDE(kallsyms_names = .); \ - PROVIDE(kallsyms_num_syms = .); \ - PROVIDE(kallsyms_relative_base = .); \ - PROVIDE(kallsyms_token_table = .); \ - PROVIDE(kallsyms_token_index = .); \ - PROVIDE(kallsyms_markers = .); \ - PROVIDE(kallsyms_seqs_of_names = .); - /* * Read only Data */ #define RO_DATA(align) \ . = ALIGN((align)); \ - PRELIMINARY_SYMBOL_DEFINITIONS \ .rodata : AT(ADDR(.rodata) - LOAD_OFFSET) { \ __start_rodata = .; \ *(.rodata) *(.rodata.*) \ diff --git a/kernel/kallsyms_internal.h b/kernel/kallsyms_internal.h index 85480274fc8fb..925f2ab22639a 100644 --- a/kernel/kallsyms_internal.h +++ b/kernel/kallsyms_internal.h @@ -4,11 +4,6 @@
#include <linux/types.h>
-/* - * These will be re-linked against their real values during the second link - * stage. Preliminary values must be provided in the linker script using the - * PROVIDE() directive so that the first link stage can complete successfully. - */ extern const unsigned long kallsyms_addresses[]; extern const int kallsyms_offsets[]; extern const u8 kallsyms_names[]; diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c index 47978efe4797c..fa53b5eef5530 100644 --- a/scripts/kallsyms.c +++ b/scripts/kallsyms.c @@ -259,12 +259,6 @@ static void shrink_table(void) } } table_cnt = pos; - - /* When valid symbol is not registered, exit to error */ - if (!table_cnt) { - fprintf(stderr, "No valid symbol.\n"); - exit(1); - } }
static void read_map(const char *in) diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index 3d9d7257143a0..83d605ba7241a 100755 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -227,6 +227,10 @@ btf_vmlinux_bin_o= kallsymso= strip_debug=
+if is_enabled CONFIG_KALLSYMS; then + kallsyms /dev/null .tmp_vmlinux.kallsyms0 +fi + if is_enabled CONFIG_DEBUG_INFO_BTF; then if ! gen_btf .tmp_vmlinux.btf .btf.vmlinux.bin.o ; then echo >&2 "Failed to generate BTF for vmlinux" @@ -239,9 +243,10 @@ if is_enabled CONFIG_KALLSYMS; then
# kallsyms support # Generate section listing all symbols and add it into vmlinux - # It's a three step process: + # It's a four step process: + # 0) Generate a dummy __kallsyms with empty symbol list. # 1) Link .tmp_vmlinux.kallsyms1 so it has all symbols and sections, - # but __kallsyms is empty. + # with a dummy __kallsyms. # Running kallsyms on that gives us .tmp_kallsyms1.o with # the right size # 2) Link .tmp_vmlinux.kallsyms2 so it now has a __kallsyms section of