| Message ID | 20230707054007.32591-1-palmer@rivosinc.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | module: Ignore RISC-V mapping symbols too | expand |
| Context | Check | Description |
|---|---|---|
| conchuod/tree_selection | fail | Failed to apply to next/pending-fixes, riscv/for-next or riscv/master |
On 2023-07-06 22:40:01-0700, Palmer Dabbelt wrote: > 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. > [..] > diff --git a/kernel/module/kallsyms.c b/kernel/module/kallsyms.c > index ef73ae7c8909..1e988e542c5d 100644 > --- a/kernel/module/kallsyms.c > +++ b/kernel/module/kallsyms.c > @@ -12,6 +12,12 @@ > #include <linux/bsearch.h> > #include "internal.h" > > +#ifdef CONFIG_RISCV > +#define IS_RISCV 1 > +#else > +#define IS_RISCV 0 > +#endif > + > /* Lookup exported symbol in given range of kernel_symbols */ > static const struct kernel_symbol *lookup_exported_symbol(const char *name, > const struct kernel_symbol *start, > @@ -289,7 +295,7 @@ 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_RISCV)) IS_BUILTIN(CONFIG_RISCV) or IS_ENABLED(CONFIG_RISCV) ? > continue; > > if (thisval <= addr && thisval > bestval) { > [..]
On 7/6/23 22:40, Palmer Dabbelt wrote: > 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> > Link: 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 Thanks. > --- > I'm not sure about a fixes here, the breakage comes from a binutils change > that's pretty much independent from the kernel. > > Plumbing in through the RISC-V-specific switch is also a bit ugly, but I'm not > sure just dropping everyone's "$"-prefixed symbols is a good idea -- the rest > of this is sort of half-way arch-specific, though, so maybe that's the way to > go? I figure it's easier to delete stuff than add it, though. > --- > include/linux/module_symbol.h | 12 +++++++++++- > kernel/module/kallsyms.c | 8 +++++++- > scripts/mod/modpost.c | 2 +- > 3 files changed, 19 insertions(+), 3 deletions(-) > > diff --git a/include/linux/module_symbol.h b/include/linux/module_symbol.h > index 7ace7ba30203..5b799942b243 100644 > --- a/include/linux/module_symbol.h > +++ b/include/linux/module_symbol.h > @@ -3,12 +3,22 @@ > #define _LINUX_MODULE_SYMBOL_H > > /* This ignores the intensely annoying "mapping symbols" found in ELF files. */ > -static inline int is_mapping_symbol(const char *str) > +static inline int is_mapping_symbol(const char *str, int is_riscv) > { > if (str[0] == '.' && str[1] == 'L') > return true; > if (str[0] == 'L' && str[1] == '0') > return true; > + /* > + * RISC-V defines various special symbols that start with "$". 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..1e988e542c5d 100644 > --- a/kernel/module/kallsyms.c > +++ b/kernel/module/kallsyms.c > @@ -12,6 +12,12 @@ > #include <linux/bsearch.h> > #include "internal.h" > > +#ifdef CONFIG_RISCV > +#define IS_RISCV 1 > +#else > +#define IS_RISCV 0 > +#endif > + > /* Lookup exported symbol in given range of kernel_symbols */ > static const struct kernel_symbol *lookup_exported_symbol(const char *name, > const struct kernel_symbol *start, > @@ -289,7 +295,7 @@ 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_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 */
On Thu, 06 Jul 2023 23:06:19 PDT (-0700), thomas@t-8ch.de wrote: > On 2023-07-06 22:40:01-0700, Palmer Dabbelt wrote: >> 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. > >> [..] > >> diff --git a/kernel/module/kallsyms.c b/kernel/module/kallsyms.c >> index ef73ae7c8909..1e988e542c5d 100644 >> --- a/kernel/module/kallsyms.c >> +++ b/kernel/module/kallsyms.c >> @@ -12,6 +12,12 @@ >> #include <linux/bsearch.h> >> #include "internal.h" >> >> +#ifdef CONFIG_RISCV >> +#define IS_RISCV 1 >> +#else >> +#define IS_RISCV 0 >> +#endif >> + >> /* Lookup exported symbol in given range of kernel_symbols */ >> static const struct kernel_symbol *lookup_exported_symbol(const char *name, >> const struct kernel_symbol *start, >> @@ -289,7 +295,7 @@ 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_RISCV)) > > IS_BUILTIN(CONFIG_RISCV) or IS_ENABLED(CONFIG_RISCV) ? Thanks, this is fixed in the v2. > >> continue; >> >> if (thisval <= addr && thisval > bestval) { > >> [..]
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..1e988e542c5d 100644 --- a/kernel/module/kallsyms.c +++ b/kernel/module/kallsyms.c @@ -12,6 +12,12 @@ #include <linux/bsearch.h> #include "internal.h" +#ifdef CONFIG_RISCV +#define IS_RISCV 1 +#else +#define IS_RISCV 0 +#endif + /* Lookup exported symbol in given range of kernel_symbols */ static const struct kernel_symbol *lookup_exported_symbol(const char *name, const struct kernel_symbol *start, @@ -289,7 +295,7 @@ 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_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 */
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> Link: https://lore.kernel.org/all/9d9e2902-5489-4bf0-d9cb-556c8e5d71c2@infradead.org/ Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com> --- I'm not sure about a fixes here, the breakage comes from a binutils change that's pretty much independent from the kernel. Plumbing in through the RISC-V-specific switch is also a bit ugly, but I'm not sure just dropping everyone's "$"-prefixed symbols is a good idea -- the rest of this is sort of half-way arch-specific, though, so maybe that's the way to go? I figure it's easier to delete stuff than add it, though. --- include/linux/module_symbol.h | 12 +++++++++++- kernel/module/kallsyms.c | 8 +++++++- scripts/mod/modpost.c | 2 +- 3 files changed, 19 insertions(+), 3 deletions(-)