On Mon, Sep 01, 2025 at 04:31:07PM +0200, Philipp Rudo wrote:
> On Tue, 19 Aug 2025 09:24:24 +0800
> Pingfan Liu <[email protected]> wrote:
>
> > The routine to search a symbol in ELF can be shared, so split it out.
> >
> > Signed-off-by: Pingfan Liu <[email protected]>
> > Cc: Baoquan He <[email protected]>
> > Cc: Dave Young <[email protected]>
> > Cc: Andrew Morton <[email protected]>
> > Cc: Philipp Rudo <[email protected]>
> > To: [email protected]
> > ---
> > 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.
>
Yes, it should be dropped. Once I placed the declaration of
elf_find_symbol() here, and later moved it behind.
Thanks,
Pingfan
> 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)
>
