From c05780ef3c190c2dafbf0be8e65d4f01103ad577 Mon Sep 17 00:00:00 2001 From: Palmer Dabbelt Date: Fri, 7 Jul 2023 09:00:51 -0700 Subject: [PATCH] module: Ignore RISC-V mapping symbols too RISC-V has an extended form of mapping symbols that we use to encode the ISA when it changes in the middle of an ELF. This trips up modpost as a build failure, I haven't yet verified it yet but I believe the kallsyms difference should result in stacks looking sane again. Reported-by: Randy Dunlap Closes: https://lore.kernel.org/all/9d9e2902-5489-4bf0-d9cb-556c8e5d71c2@infradead.org/ Signed-off-by: Palmer Dabbelt Reviewed-by: Randy Dunlap Tested-by: Randy Dunlap # build-tested Signed-off-by: Luis Chamberlain --- include/linux/module_symbol.h | 12 +++++++++++- kernel/module/kallsyms.c | 2 +- scripts/mod/modpost.c | 2 +- 3 files changed, 13 insertions(+), 3 deletions(-) diff --git a/include/linux/module_symbol.h b/include/linux/module_symbol.h index 7ace7ba30203..5b799942b243 100644 --- a/include/linux/module_symbol.h +++ b/include/linux/module_symbol.h @@ -3,12 +3,22 @@ #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) +static inline int is_mapping_symbol(const char *str, int is_riscv) { 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] == '.'); diff --git a/kernel/module/kallsyms.c b/kernel/module/kallsyms.c index ef73ae7c8909..78a1ffc399d9 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_mapping_symbol(kallsyms_symbol_name(kallsyms, i), IS_ENABLED(CONFIG_RISCV))) continue; if (thisval <= addr && thisval > bestval) { diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index b29b29707f10..7c71429d6502 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); + return !is_mapping_symbol(name, elf->hdr->e_machine == EM_RISCV); } /* Look up the nearest symbol based on the section and the address */