Commit c05780ef authored by Palmer Dabbelt's avatar Palmer Dabbelt Committed by Luis Chamberlain
Browse files

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: default avatarRandy Dunlap <rdunlap@infradead.org>
Closes: https://lore.kernel.org/all/9d9e2902-5489-4bf0-d9cb-556c8e5d71c2@infradead.org/


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
Reviewed-by: default avatarRandy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org> # build-tested
Signed-off-by: default avatarLuis Chamberlain <mcgrof@kernel.org>
parent 06c2afb8

include/linux/module_symbol.h

+11 −1
Original line number Diff line number Diff line
@@ -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] == '.');

kernel/module/kallsyms.c

+1 −1
Original line number Diff line number Diff line
@@ -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) {

scripts/mod/modpost.c

+1 −1
Original line number Diff line number Diff line
@@ -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 */