From 1e688dd2a3d6759d416616ff07afc4bb836c4213 Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Tue, 13 Apr 2021 16:38:10 +0000 Subject: powerpc/bug: Provide better flexibility to WARN_ON/__WARN_FLAGS() with asm goto Using asm goto in __WARN_FLAGS() and WARN_ON() allows more flexibility to GCC. For that add an entry to the exception table so that program_check_exception() knowns where to resume execution after a WARNING. Here are two exemples. The first one is done on PPC32 (which benefits from the previous patch), the second is on PPC64. unsigned long test(struct pt_regs *regs) { int ret; WARN_ON(regs->msr & MSR_PR); return regs->gpr[3]; } unsigned long test9w(unsigned long a, unsigned long b) { if (WARN_ON(!b)) return 0; return a / b; } Before the patch: 000003a8 : 3a8: 81 23 00 84 lwz r9,132(r3) 3ac: 71 29 40 00 andi. r9,r9,16384 3b0: 40 82 00 0c bne 3bc 3b4: 80 63 00 0c lwz r3,12(r3) 3b8: 4e 80 00 20 blr 3bc: 0f e0 00 00 twui r0,0 3c0: 80 63 00 0c lwz r3,12(r3) 3c4: 4e 80 00 20 blr 0000000000000bf0 <.test9w>: bf0: 7c 89 00 74 cntlzd r9,r4 bf4: 79 29 d1 82 rldicl r9,r9,58,6 bf8: 0b 09 00 00 tdnei r9,0 bfc: 2c 24 00 00 cmpdi r4,0 c00: 41 82 00 0c beq c0c <.test9w+0x1c> c04: 7c 63 23 92 divdu r3,r3,r4 c08: 4e 80 00 20 blr c0c: 38 60 00 00 li r3,0 c10: 4e 80 00 20 blr After the patch: 000003a8 : 3a8: 81 23 00 84 lwz r9,132(r3) 3ac: 71 29 40 00 andi. r9,r9,16384 3b0: 40 82 00 0c bne 3bc 3b4: 80 63 00 0c lwz r3,12(r3) 3b8: 4e 80 00 20 blr 3bc: 0f e0 00 00 twui r0,0 0000000000000c50 <.test9w>: c50: 7c 89 00 74 cntlzd r9,r4 c54: 79 29 d1 82 rldicl r9,r9,58,6 c58: 0b 09 00 00 tdnei r9,0 c5c: 7c 63 23 92 divdu r3,r3,r4 c60: 4e 80 00 20 blr c70: 38 60 00 00 li r3,0 c74: 4e 80 00 20 blr In the first exemple, we see GCC doesn't need to duplicate what happens after the trap. In the second exemple, we see that GCC doesn't need to emit a test and a branch in the likely path in addition to the trap. We've got some WARN_ON() in .softirqentry.text section so it needs to be added in the OTHER_TEXT_SECTIONS in modpost.c Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/389962b1b702e3c78d169e59bcfac56282889173.1618331882.git.christophe.leroy@csgroup.eu --- scripts/mod/modpost.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'scripts/mod/modpost.c') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 270a7df898e2..1209e1786af7 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -931,7 +931,7 @@ static void check_section(const char *modname, struct elf_info *elf, ".kprobes.text", ".cpuidle.text", ".noinstr.text" #define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \ ".fixup", ".entry.text", ".exception.text", ".text.*", \ - ".coldtext" + ".coldtext", ".softirqentry.text" #define INIT_SECTIONS ".init.*" #define MEM_INIT_SECTIONS ".meminit.*" -- cgit v1.2.3-70-g09d2 From e54dd93a08228b9942d708b133ad3715d92712b0 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Sat, 28 Aug 2021 18:50:59 +0900 Subject: modpost: get the *.mod file path more simply get_src_version() strips 'o' or 'lto.o' from the end of the object file path (so, postfixlen is 1 or 5), then adds 'mod'. If you look at the code closely, mod->name already holds the base path with the extension stripped. Most of the code changes made by commit 7ac204b545f2 ("modpost: lto: strip .lto from module names") was actually unneeded. sumversion.c does not need strends(), so it can get back local in modpost.c again. Signed-off-by: Masahiro Yamada --- scripts/mod/modpost.c | 11 ++++++++++- scripts/mod/modpost.h | 9 --------- scripts/mod/sumversion.c | 7 +------ 3 files changed, 11 insertions(+), 16 deletions(-) (limited to 'scripts/mod/modpost.c') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 270a7df898e2..a26139aa57fd 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -17,6 +17,7 @@ #include #include #include +#include #include #include "modpost.h" #include "../../include/linux/license.h" @@ -89,6 +90,14 @@ modpost_log(enum loglevel loglevel, const char *fmt, ...) error_occurred = true; } +static inline bool strends(const char *str, const char *postfix) +{ + if (strlen(str) < strlen(postfix)) + return false; + + return strcmp(str + strlen(str) - strlen(postfix), postfix) == 0; +} + void *do_nofail(void *ptr, const char *expr) { if (!ptr) @@ -2060,7 +2069,7 @@ static void read_symbols(const char *modname) if (!mod->is_vmlinux) { version = get_modinfo(&info, "version"); if (version || all_versions) - get_src_version(modname, mod->srcversion, + get_src_version(mod->name, mod->srcversion, sizeof(mod->srcversion) - 1); } diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h index c1a895c0d682..0c47ff95c0e2 100644 --- a/scripts/mod/modpost.h +++ b/scripts/mod/modpost.h @@ -2,7 +2,6 @@ #include #include #include -#include #include #include #include @@ -178,14 +177,6 @@ static inline unsigned int get_secindex(const struct elf_info *info, return info->symtab_shndx_start[sym - info->symtab_start]; } -static inline bool strends(const char *str, const char *postfix) -{ - if (strlen(str) < strlen(postfix)) - return false; - - return strcmp(str + strlen(str) - strlen(postfix), postfix) == 0; -} - /* file2alias.c */ extern unsigned int cross_build; void handle_moddevtable(struct module *mod, struct elf_info *info, diff --git a/scripts/mod/sumversion.c b/scripts/mod/sumversion.c index 760e6baa7eda..905c0ec291e1 100644 --- a/scripts/mod/sumversion.c +++ b/scripts/mod/sumversion.c @@ -391,14 +391,9 @@ void get_src_version(const char *modname, char sum[], unsigned sumlen) struct md4_ctx md; char *fname; char filelist[PATH_MAX + 1]; - int postfix_len = 1; - - if (strends(modname, ".lto.o")) - postfix_len = 5; /* objects for a module are listed in the first line of *.mod file. */ - snprintf(filelist, sizeof(filelist), "%.*smod", - (int)strlen(modname) - postfix_len, modname); + snprintf(filelist, sizeof(filelist), "%s.mod", modname); buf = read_text_file(filelist); -- cgit v1.2.3-70-g09d2