* [PATCH] arm64: ftrace: fix building without CONFIG_MODULES
@ 2017-06-09 10:27 Arnd Bergmann
2017-06-09 11:38 ` Will Deacon
0 siblings, 1 reply; 6+ messages in thread
From: Arnd Bergmann @ 2017-06-09 10:27 UTC (permalink / raw)
To: linux-arm-kernel
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(-)
diff --git a/arch/arm64/include/asm/module.h b/arch/arm64/include/asm/module.h
index 19bd97671bb8..ca5d024f4247 100644
--- a/arch/arm64/include/asm/module.h
+++ b/arch/arm64/include/asm/module.h
@@ -36,6 +36,12 @@ struct mod_arch_specific {
};
#endif
+#if defined(CONFIG_MODULES) && defined(CONFIG_ARM64_MODULE_PLTS)
+#define module_ftrace_trampoline(mod) ((mod)->arch.ftrace_trampoline)
+#else
+#define module_ftrace_trampoline(mod) NULL
+#endif
+
u64 module_emit_plt_entry(struct module *mod, void *loc, const Elf64_Rela *rela,
Elf64_Sym *sym);
diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c
index 8a42be0693c9..7f5eb9939a55 100644
--- a/arch/arm64/kernel/ftrace.c
+++ b/arch/arm64/kernel/ftrace.c
@@ -104,7 +104,7 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
* is added in the future, but for now, the pr_err() below
* deals with a theoretical issue only.
*/
- trampoline = (unsigned long *)mod->arch.ftrace_trampoline;
+ trampoline = module_ftrace_trampoline(mod);
if (trampoline[0] != addr) {
if (trampoline[0] != 0) {
pr_err("ftrace: far branches to multiple entry points unsupported inside a single module\n");
diff --git a/include/linux/module.h b/include/linux/module.h
index 21f56393602f..9196f532f158 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -671,6 +671,11 @@ static inline bool is_module_text_address(unsigned long addr)
return false;
}
+static inline bool within_module(unsigned long addr, const struct module *mod)
+{
+ return false;
+}
+
/* Get/put a kernel symbol (calls should be symmetric) */
#define symbol_get(x) ({ extern typeof(x) x __attribute__((weak)); &(x); })
#define symbol_put(x) do { } while (0)
--
2.9.0
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH] arm64: ftrace: fix building without CONFIG_MODULES
2017-06-09 10:27 [PATCH] arm64: ftrace: fix building without CONFIG_MODULES Arnd Bergmann
@ 2017-06-09 11:38 ` Will Deacon
2017-06-09 18:57 ` Arnd Bergmann
0 siblings, 1 reply; 6+ messages in thread
From: Will Deacon @ 2017-06-09 11:38 UTC (permalink / raw)
To: linux-arm-kernel
Hi Arnd,
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?
Will
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH] arm64: ftrace: fix building without CONFIG_MODULES
2017-06-09 11:38 ` Will Deacon
@ 2017-06-09 18:57 ` Arnd Bergmann
2017-06-12 12:48 ` Will Deacon
0 siblings, 1 reply; 6+ messages in thread
From: Arnd Bergmann @ 2017-06-09 18:57 UTC (permalink / raw)
To: linux-arm-kernel
On Fri, Jun 9, 2017 at 1:38 PM, Will Deacon <will.deacon@arm.com> wrote:
> Hi Arnd,
>
> 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
Arnd
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH] arm64: ftrace: fix building without CONFIG_MODULES
2017-06-09 18:57 ` Arnd Bergmann
@ 2017-06-12 12:48 ` Will Deacon
2017-06-12 13:01 ` Ard Biesheuvel
2017-06-12 14:22 ` Arnd Bergmann
0 siblings, 2 replies; 6+ messages in thread
From: Will Deacon @ 2017-06-12 12:48 UTC (permalink / raw)
To: linux-arm-kernel
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();
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH] arm64: ftrace: fix building without CONFIG_MODULES
2017-06-12 12:48 ` Will Deacon
@ 2017-06-12 13:01 ` Ard Biesheuvel
2017-06-12 14:22 ` Arnd Bergmann
1 sibling, 0 replies; 6+ messages in thread
From: Ard Biesheuvel @ 2017-06-12 13:01 UTC (permalink / raw)
To: linux-arm-kernel
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();
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH] arm64: ftrace: fix building without CONFIG_MODULES
2017-06-12 12:48 ` Will Deacon
2017-06-12 13:01 ` Ard Biesheuvel
@ 2017-06-12 14:22 ` Arnd Bergmann
1 sibling, 0 replies; 6+ messages in thread
From: Arnd Bergmann @ 2017-06-12 14:22 UTC (permalink / raw)
To: linux-arm-kernel
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
^ permalink raw reply [flat|nested] 6+ messages in thread
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2017-06-09 10:27 [PATCH] arm64: ftrace: fix building without CONFIG_MODULES Arnd Bergmann
2017-06-09 11:38 ` Will Deacon
2017-06-09 18:57 ` Arnd Bergmann
2017-06-12 12:48 ` Will Deacon
2017-06-12 13:01 ` Ard Biesheuvel
2017-06-12 14:22 ` Arnd Bergmann
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