| Message ID | 20170612124805.GA11581@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 12 June 2017 at 14:48, Will Deacon <will.deacon@arm.com> wrote: > 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. I agree that this makes more sense in this particular case. Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Interestingly, ARM64_MODULE_PLTS does not depend on CONFIG_MODULES, but I can't remember whether that was deliberate or an oversight. > See below. > > --->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(); >
On Mon, Jun 12, 2017 at 2:48 PM, Will Deacon <will.deacon@arm.com> wrote: > 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: >> > 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. Yes, good idea. Arnd
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();