On Sat, Jul 22, 2023 at 12:20 AM Palmer Dabbelt <palmer@xxxxxxxxxxxx> wrote:
>
> Trying to restrict the '$'-prefix change to RISC-V caused some fallout,
> so let's just treat all those symbols as special.
>
> Fixes: c05780ef3c1 ("module: Ignore RISC-V mapping symbols too")
> Link: https://lore.kernel.org/all/20230712015747.77263-1-wangkefeng.wang@xxxxxxxxxx/
> Signed-off-by: Palmer Dabbelt <palmer@xxxxxxxxxxxx>
Reviewed-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
> ---
> It wasn't clear if we should just revert the original patch and spin a
> new one, but looks like this is in at least some trees so I sent a
> follow-on patch -- at least this way I can make coffee before forgetting
> to send it ;)
> ---
> include/linux/module_symbol.h | 16 ++--------------
> kernel/module/kallsyms.c | 2 +-
> scripts/mod/modpost.c | 2 +-
> 3 files changed, 4 insertions(+), 16 deletions(-)
>
> diff --git a/include/linux/module_symbol.h b/include/linux/module_symbol.h
> index 5b799942b243..1269543d0634 100644
> --- a/include/linux/module_symbol.h
> +++ b/include/linux/module_symbol.h
> @@ -3,25 +3,13 @@
> #define _LINUX_MODULE_SYMBOL_H
>
> /* This ignores the intensely annoying "mapping symbols" found in ELF files. */
> -static inline int is_mapping_symbol(const char *str, int is_riscv)
> +static inline int is_mapping_symbol(const char *str)
> {
> if (str[0] == '.' && str[1] == 'L')
> return true;
> if (str[0] == 'L' && str[1] == '0')
> return true;
> - /*
> - * RISC-V defines various special symbols that start with "$". The
> - * mapping symbols, which exist to differentiate between incompatible
> - * instruction encodings when disassembling, show up all over the place
> - * and are generally not meant to be treated like other symbols. So
> - * just ignore any of the special symbols.
> - */
> - if (is_riscv)
> - return str[0] == '$';
> -
> - return str[0] == '$' &&
> - (str[1] == 'a' || str[1] == 'd' || str[1] == 't' || str[1] == 'x')
> - && (str[2] == '\0' || str[2] == '.');
> + return str[0] == '$';
> }
>
> #endif /* _LINUX_MODULE_SYMBOL_H */
> diff --git a/kernel/module/kallsyms.c b/kernel/module/kallsyms.c
> index 78a1ffc399d9..ef73ae7c8909 100644
> --- a/kernel/module/kallsyms.c
> +++ b/kernel/module/kallsyms.c
> @@ -289,7 +289,7 @@ static const char *find_kallsyms_symbol(struct module *mod,
> * and inserted at a whim.
> */
> if (*kallsyms_symbol_name(kallsyms, i) == '\0' ||
> - is_mapping_symbol(kallsyms_symbol_name(kallsyms, i), IS_ENABLED(CONFIG_RISCV)))
> + is_mapping_symbol(kallsyms_symbol_name(kallsyms, i)))
> continue;
>
> if (thisval <= addr && thisval > bestval) {
> diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
> index 7c71429d6502..b29b29707f10 100644
> --- a/scripts/mod/modpost.c
> +++ b/scripts/mod/modpost.c
> @@ -1052,7 +1052,7 @@ static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
>
> if (!name || !strlen(name))
> return 0;
> - return !is_mapping_symbol(name, elf->hdr->e_machine == EM_RISCV);
> + return !is_mapping_symbol(name);
> }
>
> /* Look up the nearest symbol based on the section and the address */
> --
> 2.41.0
>
--
Best Regards
Masahiro Yamada
