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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 <rdunlap@infradead.org>
Closes: https://lore.kernel.org/all/9d9e2902-5489-4bf0-d9cb-556c8e5d71c2@infradead.org/
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org> # build-tested
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
This commit is contained in:
Palmer Dabbelt 2023-07-07 09:00:51 -07:00 committed by Luis Chamberlain
parent 06c2afb862
commit c05780ef3c
3 changed files with 13 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
include/linux/module_symbol.h
View File

@ -3,12 +3,22 @@
#define _LINUX_MODULE_SYMBOL_H #define _LINUX_MODULE_SYMBOL_H
/* This ignores the intensely annoying "mapping symbols" found in ELF files. */ /* 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') if (str[0] == '.' && str[1] == 'L')
return true; return true;
if (str[0] == 'L' && str[1] == '0') if (str[0] == 'L' && str[1] == '0')
return true; 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] == '$' && return str[0] == '$' &&
(str[1] == 'a' || str[1] == 'd' || str[1] == 't' || str[1] == 'x') (str[1] == 'a' || str[1] == 'd' || str[1] == 't' || str[1] == 'x')
&& (str[2] == '\0' || str[2] == '.'); && (str[2] == '\0' || str[2] == '.');

2
kernel/module/kallsyms.c
View File

@ -289,7 +289,7 @@ static const char *find_kallsyms_symbol(struct module *mod,
* and inserted at a whim. * and inserted at a whim.
*/ */
if (*kallsyms_symbol_name(kallsyms, i) == '\0' || 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; continue;
if (thisval <= addr && thisval > bestval) { if (thisval <= addr && thisval > bestval) {

2
scripts/mod/modpost.c
View File

@ -1052,7 +1052,7 @@ static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
if (!name || !strlen(name)) if (!name || !strlen(name))
return 0; 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 */ /* Look up the nearest symbol based on the section and the address */