On Tue, 19 Aug 2025 09:24:24 +0800
Pingfan Liu <pi...@redhat.com> wrote:
> The routine to search a symbol in ELF can be shared, so split it out.
>
> Signed-off-by: Pingfan Liu <pi...@redhat.com>
> Cc: Baoquan He <b...@redhat.com>
> Cc: Dave Young <dyo...@redhat.com>
> Cc: Andrew Morton <a...@linux-foundation.org>
> Cc: Philipp Rudo <pr...@redhat.com>
> To: kexec@lists.infradead.org
> ---
> include/linux/kexec.h | 8 ++++
> kernel/kexec_file.c | 86 +++++++++++++++++++++++--------------------
> 2 files changed, 54 insertions(+), 40 deletions(-)
>
> diff --git a/include/linux/kexec.h b/include/linux/kexec.h
> index 8f7322c932fb5..2998d8da09d86 100644
> --- a/include/linux/kexec.h
> +++ b/include/linux/kexec.h
> @@ -23,6 +23,10 @@
> #include <uapi/linux/kexec.h>
> #include <linux/verification.h>
>
> +#if defined(CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY) ||
> defined(CONFIG_KEXEC_PE_IMAGE)
> +#include <linux/module.h>
> +#endif
> +
What is linux/module.h used for? Plus module.h already gets included a
little below, when CONFIG_KEXEC_CORE is set, which should always be the
case for those two configs.
Thanks
Philipp
> extern note_buf_t __percpu *crash_notes;
>
> #ifdef CONFIG_CRASH_DUMP
> @@ -550,6 +554,10 @@ void set_kexec_sig_enforced(void);
> static inline void set_kexec_sig_enforced(void) {}
> #endif
>
> +#if defined(CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY) ||
> defined(CONFIG_KEXEC_PE_IMAGE)
> +const Elf_Sym *elf_find_symbol(const Elf_Ehdr *ehdr, const char *name);
> +#endif
> +
> #endif /* !defined(__ASSEBMLY__) */
>
> #endif /* LINUX_KEXEC_H */
> diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
> index 4780d8aae24e7..137049e7e2410 100644
> --- a/kernel/kexec_file.c
> +++ b/kernel/kexec_file.c
> @@ -880,6 +880,51 @@ static int kexec_calculate_store_digests(struct kimage
> *image)
> return ret;
> }
>
> +#if defined(CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY) ||
> defined(CONFIG_KEXEC_PE_IMAGE)
> +const Elf_Sym *elf_find_symbol(const Elf_Ehdr *ehdr, const char *name)
> +{
> + const Elf_Shdr *sechdrs;
> + const Elf_Sym *syms;
> + const char *strtab;
> + int i, k;
> +
> + sechdrs = (void *)ehdr + ehdr->e_shoff;
> +
> + for (i = 0; i < ehdr->e_shnum; i++) {
> + if (sechdrs[i].sh_type != SHT_SYMTAB)
> + continue;
> +
> + if (sechdrs[i].sh_link >= ehdr->e_shnum)
> + /* Invalid strtab section number */
> + continue;
> + strtab = (void *)ehdr + sechdrs[sechdrs[i].sh_link].sh_offset;
> + syms = (void *)ehdr + sechdrs[i].sh_offset;
> +
> + /* Go through symbols for a match */
> + for (k = 0; k < sechdrs[i].sh_size/sizeof(Elf_Sym); k++) {
> + if (ELF_ST_BIND(syms[k].st_info) != STB_GLOBAL)
> + continue;
> +
> + if (strcmp(strtab + syms[k].st_name, name) != 0)
> + continue;
> +
> + if (syms[k].st_shndx == SHN_UNDEF ||
> + syms[k].st_shndx >= ehdr->e_shnum) {
> + pr_debug("Symbol: %s has bad section index
> %d.\n",
> + name, syms[k].st_shndx);
> + return NULL;
> + }
> +
> + /* Found the symbol we are looking for */
> + return &syms[k];
> + }
> + }
> +
> + return NULL;
> +}
> +
> +#endif
> +
> #ifdef CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY
> /*
> * kexec_purgatory_setup_kbuf - prepare buffer to load purgatory.
> @@ -1137,49 +1182,10 @@ int kexec_load_purgatory(struct kimage *image, struct
> kexec_buf *kbuf)
> static const Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi,
> const char *name)
> {
> - const Elf_Shdr *sechdrs;
> - const Elf_Ehdr *ehdr;
> - const Elf_Sym *syms;
> - const char *strtab;
> - int i, k;
> -
> if (!pi->ehdr)
> return NULL;
>
> - ehdr = pi->ehdr;
> - sechdrs = (void *)ehdr + ehdr->e_shoff;
> -
> - for (i = 0; i < ehdr->e_shnum; i++) {
> - if (sechdrs[i].sh_type != SHT_SYMTAB)
> - continue;
> -
> - if (sechdrs[i].sh_link >= ehdr->e_shnum)
> - /* Invalid strtab section number */
> - continue;
> - strtab = (void *)ehdr + sechdrs[sechdrs[i].sh_link].sh_offset;
> - syms = (void *)ehdr + sechdrs[i].sh_offset;
> -
> - /* Go through symbols for a match */
> - for (k = 0; k < sechdrs[i].sh_size/sizeof(Elf_Sym); k++) {
> - if (ELF_ST_BIND(syms[k].st_info) != STB_GLOBAL)
> - continue;
> -
> - if (strcmp(strtab + syms[k].st_name, name) != 0)
> - continue;
> -
> - if (syms[k].st_shndx == SHN_UNDEF ||
> - syms[k].st_shndx >= ehdr->e_shnum) {
> - pr_debug("Symbol: %s has bad section index
> %d.\n",
> - name, syms[k].st_shndx);
> - return NULL;
> - }
> -
> - /* Found the symbol we are looking for */
> - return &syms[k];
> - }
> - }
> -
> - return NULL;
> + return elf_find_symbol(pi->ehdr, name);
> }
>
> void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name)
