Messages in this thread Patch in this message | | | Date | Mon, 12 Jun 2017 13:48:06 +0100 | From | Will Deacon <> | Subject | Re: [PATCH] arm64: ftrace: fix building without CONFIG_MODULES |
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On Fri, Jun 09, 2017 at 08:57:31PM +0200, Arnd Bergmann wrote: > On Fri, Jun 9, 2017 at 1:38 PM, Will Deacon <will.deacon@arm.com> wrote: > > On Fri, Jun 09, 2017 at 12:27:06PM +0200, Arnd Bergmann wrote: > >> When CONFIG_MODULES is disabled, we cannot dereference a module pointer: > >> > >> arch/arm64/kernel/ftrace.c: In function 'ftrace_make_call': > >> arch/arm64/kernel/ftrace.c:107:36: error: dereferencing pointer to incomplete type 'struct module' > >> trampoline = (unsigned long *)mod->arch.ftrace_trampoline; > >> > >> Also, the within_module() function is not defined: > >> > >> arch/arm64/kernel/ftrace.c: In function 'ftrace_make_nop': > >> arch/arm64/kernel/ftrace.c:171:8: error: implicit declaration of function 'within_module'; did you mean 'init_module'? [-Werror=implicit-function-declaration] > >> > >> This addresses both by adding the appropriate stubs. > >> > >> Fixes: e71a4e1bebaf ("arm64: ftrace: add support for far branches to dynamic ftrace") > >> Signed-off-by: Arnd Bergmann <arnd@arndb.de> > >> --- > >> arch/arm64/include/asm/module.h | 6 ++++++ > >> arch/arm64/kernel/ftrace.c | 2 +- > >> include/linux/module.h | 5 +++++ > >> 3 files changed, 12 insertions(+), 1 deletion(-) > > > > I can't seem to reproduce this simply by disabling MODULES in defconfig. > > Could you share your .config, please? > > This is the randconfig I used: https://pastebin.com/SfKBY7f8
Thanks, I was forgetting to enable ftrace. I think a simpler patch (and one that I can just apply via arm64) is switching the IS_ENABLEDs out for #ifdefs. See below.
Will
--->8
diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c index 8a42be0693c9..401aa27808a4 100644 --- a/arch/arm64/kernel/ftrace.c +++ b/arch/arm64/kernel/ftrace.c @@ -71,11 +71,12 @@ int ftrace_update_ftrace_func(ftrace_func_t func) int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) { unsigned long pc = rec->ip; - long offset = (long)pc - (long)addr; u32 old, new; - if (IS_ENABLED(CONFIG_ARM64_MODULE_PLTS) && - (offset < -SZ_128M || offset >= SZ_128M)) { +#ifdef CONFIG_ARM64_MODULE_PLTS + long offset = (long)pc - (long)addr; + + if (offset < -SZ_128M || offset >= SZ_128M) { unsigned long *trampoline; struct module *mod; @@ -121,6 +122,7 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) } addr = (unsigned long)&trampoline[1]; } +#endif /* CONFIG_ARM64_MODULE_PLTS */ old = aarch64_insn_gen_nop(); new = aarch64_insn_gen_branch_imm(pc, addr, AARCH64_INSN_BRANCH_LINK); @@ -135,12 +137,13 @@ int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr) { unsigned long pc = rec->ip; - long offset = (long)pc - (long)addr; bool validate = true; u32 old = 0, new; - if (IS_ENABLED(CONFIG_ARM64_MODULE_PLTS) && - (offset < -SZ_128M || offset >= SZ_128M)) { +#ifdef CONFIG_ARM64_MODULE_PLTS + long offset = (long)pc - (long)addr; + + if (offset < -SZ_128M || offset >= SZ_128M) { u32 replaced; /* @@ -177,6 +180,7 @@ int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, old = aarch64_insn_gen_branch_imm(pc, addr, AARCH64_INSN_BRANCH_LINK); } +#endif /* CONFIG_ARM64_MODULE_PLTS */ new = aarch64_insn_gen_nop();
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