Re: Re: Re: [RFT PATCH -next v3] [BUGFIX] kprobes: Fix "Failed to find blacklist" error on ia64 and ppc64
On Thu, 2014-06-19 at 20:20 +0900, Masami Hiramatsu wrote:
> (2014/06/19 20:01), Masami Hiramatsu wrote:
>
> > Ah, those messages should be shown in dmesg when booting if it doesn't
> > work,
> > because the messages are printed by initialization process of kprobe
> > blacklist.
> > So, reproducing it is just enabling CONFIG_KPROBES and boot it.
> Well, we don't get those messages on Power, since the kallsyms has the
> entries for ".function_name". The correct way to verify is, either :
> >>>
> >>> Hmm, that seems another issue on powerpc. Is that expected(and designed)
> >>> behavior?
> >> AFAIK, yes, it is.
> >> To be more precise :
> >>
> >> we have 'foo' and '.foo' for a function foo(), where 'foo' points to the
> >> function_entry and '.foo' points to the actual function.
> >
> > Ah, I see. So if we run
> >
> > func_ptr p = foo;
> > return p == kallsyms_lookup_name(".foo");
> >
> > it returns true.
>
> One more thing I should know, is the address of ".function_name" within the
> kernel text? In other words, does kernel_text_address() return true for that
> address? If not, it's easy to verify the address.
Yes. That is the text address, kernel_text_address() should definitely return
true.
On 64-bit, ABIv1, "foo" points to the function descriptor, in the ".opd"
section.
".foo" points to the actual text of the function, in ".text".
On 64-bit, ABIv2, "foo" points to the text in ".text". There are no dot
symbols.
cheers
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Re: Re: Re: [RFT PATCH -next v3] [BUGFIX] kprobes: Fix "Failed to find blacklist" error on ia64 and ppc64
(2014/06/19 20:01), Masami Hiramatsu wrote:
> Ah, those messages should be shown in dmesg when booting if it doesn't
> work,
> because the messages are printed by initialization process of kprobe
> blacklist.
> So, reproducing it is just enabling CONFIG_KPROBES and boot it.
Well, we don't get those messages on Power, since the kallsyms has the
entries for ".function_name". The correct way to verify is, either :
>>>
>>> Hmm, that seems another issue on powerpc. Is that expected(and designed)
>>> behavior?
>> AFAIK, yes, it is.
>> To be more precise :
>>
>> we have 'foo' and '.foo' for a function foo(), where 'foo' points to the
>> function_entry and '.foo' points to the actual function.
>
> Ah, I see. So if we run
>
> func_ptr p = foo;
> return p == kallsyms_lookup_name(".foo");
>
> it returns true.
One more thing I should know, is the address of ".function_name" within the
kernel text? In other words, does kernel_text_address() return true for that
address? If not, it's easy to verify the address.
Thank you,
--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu...@hitachi.com
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Re: Re: [RFT PATCH -next v3] [BUGFIX] kprobes: Fix "Failed to find blacklist" error on ia64 and ppc64
(2014/06/19 18:45), Suzuki K. Poulose wrote:
> On 06/19/2014 12:56 PM, Masami Hiramatsu wrote:
>> (2014/06/19 15:40), Suzuki K. Poulose wrote:
>>> On 06/19/2014 10:22 AM, Masami Hiramatsu wrote:
(2014/06/19 10:30), Michael Ellerman wrote:
> On Wed, 2014-06-18 at 17:46 +0900, Masami Hiramatsu wrote:
>> (2014/06/18 16:56), Michael Ellerman wrote:
>>> On Fri, 2014-06-06 at 15:38 +0900, Masami Hiramatsu wrote:
Ping?
I guess this should go to 3.16 branch, shouldn't it?
>>>
> diff --git a/arch/powerpc/include/asm/types.h
> b/arch/powerpc/include/asm/types.h
> index bfb6ded..8b89d65 100644
> --- a/arch/powerpc/include/asm/types.h
> +++ b/arch/powerpc/include/asm/types.h
> @@ -25,6 +25,17 @@ typedef struct {
> unsigned long env;
> } func_descr_t;
>
> +#if defined(CONFIG_PPC64) && (!defined(_CALL_ELF) || _CALL_ELF == 1)
> +/*
> + * On PPC64 ABIv1 the function pointer actually points to the
> + * function's descriptor. The first entry in the descriptor is the
> + * address of the function text.
> + */
> +#define function_entry(fn) (((func_descr_t *)(fn))->entry)
> +#else
> +#define function_entry(fn) ((unsigned long)(fn))
> +#endif
>>>
>>> We already have ppc_function_entry(), can't you use that?
>>
>> I'd like to ask you whether the address which ppc_function_entry()
>> returns on
>> PPC ABIv2 is really same address in kallsyms or not.
>> As you can see, kprobes uses function_entry() to get the actual entry
>> address
>> where kallsyms knows. I have not much information about that, but it
>> seems that
>> the "global entry point" is the address which kallsyms knows, isn't it?
>
> OK. I'm not sure off the top of my head which address kallsyms knows
> about, but
> yes it's likely that it is the global entry point.
>
> I recently sent a patch to add ppc_global_function_entry(), because we
> need it
> in the ftrace code. Once that is merged you could use that.
Yeah, I could use that. But since this is used in arch-independent code
(e.g. IA64
needs similar macro), I think we'd better define function_entry() in
asm/types.h for
general use (for kallsyms), and rename ppc_function_entry to
local_function_entry()
in asm/code-patching.h.
> How do you hit the original problem, you don't actually specify in your
> commit
> message? Something with kprobes obviously, but what exactly? I'll try and
> reproduce it here.
Ah, those messages should be shown in dmesg when booting if it doesn't
work,
because the messages are printed by initialization process of kprobe
blacklist.
So, reproducing it is just enabling CONFIG_KPROBES and boot it.
>>> Well, we don't get those messages on Power, since the kallsyms has the
>>> entries for ".function_name". The correct way to verify is, either :
>>
>> Hmm, that seems another issue on powerpc. Is that expected(and designed)
>> behavior?
> AFAIK, yes, it is.
> To be more precise :
>
> we have 'foo' and '.foo' for a function foo(), where 'foo' points to the
> function_entry and '.foo' points to the actual function.
Ah, I see. So if we run
func_ptr p = foo;
return p == kallsyms_lookup_name(".foo");
it returns true.
> So, a kallsyms_lookup_size_offset() on both 'foo' and '.foo' will return
> a hit. So, if we make sure we use the value of '.foo' (by using the
> appropriate macros) we should be fine.
>
> And if so, how I can verify when initializing blacklist?
>> (should I better use kallsyms_lookup() and kallsyms_lookup_name() for
>> verification?)
> One way to verify would be to make sure the symbol starts with '.' from
> the result of the current kallsyms_lookup_size_offset() for PPC.
OK, I'll do that as another enhancement, since the bug reported here
will be fixed with our patch.
Anyway, this patch itself should go into 3.16 tree to fix actual bug.
Thanks,
--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu...@hitachi.com
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Re: Re: [RFT PATCH -next v3] [BUGFIX] kprobes: Fix "Failed to find blacklist" error on ia64 and ppc64
(2014/06/19 15:40), Suzuki K. Poulose wrote:
> On 06/19/2014 10:22 AM, Masami Hiramatsu wrote:
>> (2014/06/19 10:30), Michael Ellerman wrote:
>>> On Wed, 2014-06-18 at 17:46 +0900, Masami Hiramatsu wrote:
(2014/06/18 16:56), Michael Ellerman wrote:
> On Fri, 2014-06-06 at 15:38 +0900, Masami Hiramatsu wrote:
>> Ping?
>>
>> I guess this should go to 3.16 branch, shouldn't it?
>
>>> diff --git a/arch/powerpc/include/asm/types.h
>>> b/arch/powerpc/include/asm/types.h
>>> index bfb6ded..8b89d65 100644
>>> --- a/arch/powerpc/include/asm/types.h
>>> +++ b/arch/powerpc/include/asm/types.h
>>> @@ -25,6 +25,17 @@ typedef struct {
>>> unsigned long env;
>>> } func_descr_t;
>>>
>>> +#if defined(CONFIG_PPC64) && (!defined(_CALL_ELF) || _CALL_ELF == 1)
>>> +/*
>>> + * On PPC64 ABIv1 the function pointer actually points to the
>>> + * function's descriptor. The first entry in the descriptor is the
>>> + * address of the function text.
>>> + */
>>> +#define function_entry(fn) (((func_descr_t *)(fn))->entry)
>>> +#else
>>> +#define function_entry(fn) ((unsigned long)(fn))
>>> +#endif
>
> We already have ppc_function_entry(), can't you use that?
I'd like to ask you whether the address which ppc_function_entry() returns
on
PPC ABIv2 is really same address in kallsyms or not.
As you can see, kprobes uses function_entry() to get the actual entry
address
where kallsyms knows. I have not much information about that, but it seems
that
the "global entry point" is the address which kallsyms knows, isn't it?
>>>
>>> OK. I'm not sure off the top of my head which address kallsyms knows about,
>>> but
>>> yes it's likely that it is the global entry point.
>>>
>>> I recently sent a patch to add ppc_global_function_entry(), because we need
>>> it
>>> in the ftrace code. Once that is merged you could use that.
>>
>> Yeah, I could use that. But since this is used in arch-independent code
>> (e.g. IA64
>> needs similar macro), I think we'd better define function_entry() in
>> asm/types.h for
>> general use (for kallsyms), and rename ppc_function_entry to
>> local_function_entry()
>> in asm/code-patching.h.
>>
>>
>>> How do you hit the original problem, you don't actually specify in your
>>> commit
>>> message? Something with kprobes obviously, but what exactly? I'll try and
>>> reproduce it here.
>>
>> Ah, those messages should be shown in dmesg when booting if it doesn't work,
>> because the messages are printed by initialization process of kprobe
>> blacklist.
>> So, reproducing it is just enabling CONFIG_KPROBES and boot it.
> Well, we don't get those messages on Power, since the kallsyms has the
> entries for ".function_name". The correct way to verify is, either :
Hmm, that seems another issue on powerpc. Is that expected(and designed)
behavior? And if so, how I can verify when initializing blacklist?
(should I better use kallsyms_lookup() and kallsyms_lookup_name() for
verification?)
Thank you,
>
> 1) Dump the black_list via xmon ( see :
> https://lkml.org/lkml/2014/5/29/893 ) and verify the entries.
>
> or
>
> 2) Issue a kprobe on a black listed entry and hit a success,(which we
> will, since we don't check the actual function address).
>
> Thanks
> Suzuki
>
>
>>
>> Thank you,
>>
--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu...@hitachi.com
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Re: Re: [RFT PATCH -next v3] [BUGFIX] kprobes: Fix Failed to find blacklist error on ia64 and ppc64
(2014/06/19 15:40), Suzuki K. Poulose wrote:
On 06/19/2014 10:22 AM, Masami Hiramatsu wrote:
(2014/06/19 10:30), Michael Ellerman wrote:
On Wed, 2014-06-18 at 17:46 +0900, Masami Hiramatsu wrote:
(2014/06/18 16:56), Michael Ellerman wrote:
On Fri, 2014-06-06 at 15:38 +0900, Masami Hiramatsu wrote:
Ping?
I guess this should go to 3.16 branch, shouldn't it?
diff --git a/arch/powerpc/include/asm/types.h
b/arch/powerpc/include/asm/types.h
index bfb6ded..8b89d65 100644
--- a/arch/powerpc/include/asm/types.h
+++ b/arch/powerpc/include/asm/types.h
@@ -25,6 +25,17 @@ typedef struct {
unsigned long env;
} func_descr_t;
+#if defined(CONFIG_PPC64) (!defined(_CALL_ELF) || _CALL_ELF == 1)
+/*
+ * On PPC64 ABIv1 the function pointer actually points to the
+ * function's descriptor. The first entry in the descriptor is the
+ * address of the function text.
+ */
+#define function_entry(fn) (((func_descr_t *)(fn))-entry)
+#else
+#define function_entry(fn) ((unsigned long)(fn))
+#endif
We already have ppc_function_entry(), can't you use that?
I'd like to ask you whether the address which ppc_function_entry() returns
on
PPC ABIv2 is really same address in kallsyms or not.
As you can see, kprobes uses function_entry() to get the actual entry
address
where kallsyms knows. I have not much information about that, but it seems
that
the global entry point is the address which kallsyms knows, isn't it?
OK. I'm not sure off the top of my head which address kallsyms knows about,
but
yes it's likely that it is the global entry point.
I recently sent a patch to add ppc_global_function_entry(), because we need
it
in the ftrace code. Once that is merged you could use that.
Yeah, I could use that. But since this is used in arch-independent code
(e.g. IA64
needs similar macro), I think we'd better define function_entry() in
asm/types.h for
general use (for kallsyms), and rename ppc_function_entry to
local_function_entry()
in asm/code-patching.h.
How do you hit the original problem, you don't actually specify in your
commit
message? Something with kprobes obviously, but what exactly? I'll try and
reproduce it here.
Ah, those messages should be shown in dmesg when booting if it doesn't work,
because the messages are printed by initialization process of kprobe
blacklist.
So, reproducing it is just enabling CONFIG_KPROBES and boot it.
Well, we don't get those messages on Power, since the kallsyms has the
entries for .function_name. The correct way to verify is, either :
Hmm, that seems another issue on powerpc. Is that expected(and designed)
behavior? And if so, how I can verify when initializing blacklist?
(should I better use kallsyms_lookup() and kallsyms_lookup_name() for
verification?)
Thank you,
1) Dump the black_list via xmon ( see :
https://lkml.org/lkml/2014/5/29/893 ) and verify the entries.
or
2) Issue a kprobe on a black listed entry and hit a success,(which we
will, since we don't check the actual function address).
Thanks
Suzuki
Thank you,
--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu...@hitachi.com
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
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Please read the FAQ at http://www.tux.org/lkml/
Re: Re: [RFT PATCH -next v3] [BUGFIX] kprobes: Fix Failed to find blacklist error on ia64 and ppc64
(2014/06/19 18:45), Suzuki K. Poulose wrote:
On 06/19/2014 12:56 PM, Masami Hiramatsu wrote:
(2014/06/19 15:40), Suzuki K. Poulose wrote:
On 06/19/2014 10:22 AM, Masami Hiramatsu wrote:
(2014/06/19 10:30), Michael Ellerman wrote:
On Wed, 2014-06-18 at 17:46 +0900, Masami Hiramatsu wrote:
(2014/06/18 16:56), Michael Ellerman wrote:
On Fri, 2014-06-06 at 15:38 +0900, Masami Hiramatsu wrote:
Ping?
I guess this should go to 3.16 branch, shouldn't it?
diff --git a/arch/powerpc/include/asm/types.h
b/arch/powerpc/include/asm/types.h
index bfb6ded..8b89d65 100644
--- a/arch/powerpc/include/asm/types.h
+++ b/arch/powerpc/include/asm/types.h
@@ -25,6 +25,17 @@ typedef struct {
unsigned long env;
} func_descr_t;
+#if defined(CONFIG_PPC64) (!defined(_CALL_ELF) || _CALL_ELF == 1)
+/*
+ * On PPC64 ABIv1 the function pointer actually points to the
+ * function's descriptor. The first entry in the descriptor is the
+ * address of the function text.
+ */
+#define function_entry(fn) (((func_descr_t *)(fn))-entry)
+#else
+#define function_entry(fn) ((unsigned long)(fn))
+#endif
We already have ppc_function_entry(), can't you use that?
I'd like to ask you whether the address which ppc_function_entry()
returns on
PPC ABIv2 is really same address in kallsyms or not.
As you can see, kprobes uses function_entry() to get the actual entry
address
where kallsyms knows. I have not much information about that, but it
seems that
the global entry point is the address which kallsyms knows, isn't it?
OK. I'm not sure off the top of my head which address kallsyms knows
about, but
yes it's likely that it is the global entry point.
I recently sent a patch to add ppc_global_function_entry(), because we
need it
in the ftrace code. Once that is merged you could use that.
Yeah, I could use that. But since this is used in arch-independent code
(e.g. IA64
needs similar macro), I think we'd better define function_entry() in
asm/types.h for
general use (for kallsyms), and rename ppc_function_entry to
local_function_entry()
in asm/code-patching.h.
How do you hit the original problem, you don't actually specify in your
commit
message? Something with kprobes obviously, but what exactly? I'll try and
reproduce it here.
Ah, those messages should be shown in dmesg when booting if it doesn't
work,
because the messages are printed by initialization process of kprobe
blacklist.
So, reproducing it is just enabling CONFIG_KPROBES and boot it.
Well, we don't get those messages on Power, since the kallsyms has the
entries for .function_name. The correct way to verify is, either :
Hmm, that seems another issue on powerpc. Is that expected(and designed)
behavior?
AFAIK, yes, it is.
To be more precise :
we have 'foo' and '.foo' for a function foo(), where 'foo' points to the
function_entry and '.foo' points to the actual function.
Ah, I see. So if we run
func_ptr p = foo;
return p == kallsyms_lookup_name(.foo);
it returns true.
So, a kallsyms_lookup_size_offset() on both 'foo' and '.foo' will return
a hit. So, if we make sure we use the value of '.foo' (by using the
appropriate macros) we should be fine.
And if so, how I can verify when initializing blacklist?
(should I better use kallsyms_lookup() and kallsyms_lookup_name() for
verification?)
One way to verify would be to make sure the symbol starts with '.' from
the result of the current kallsyms_lookup_size_offset() for PPC.
OK, I'll do that as another enhancement, since the bug reported here
will be fixed with our patch.
Anyway, this patch itself should go into 3.16 tree to fix actual bug.
Thanks,
--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu...@hitachi.com
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: Re: Re: [RFT PATCH -next v3] [BUGFIX] kprobes: Fix Failed to find blacklist error on ia64 and ppc64
(2014/06/19 20:01), Masami Hiramatsu wrote: Ah, those messages should be shown in dmesg when booting if it doesn't work, because the messages are printed by initialization process of kprobe blacklist. So, reproducing it is just enabling CONFIG_KPROBES and boot it. Well, we don't get those messages on Power, since the kallsyms has the entries for .function_name. The correct way to verify is, either : Hmm, that seems another issue on powerpc. Is that expected(and designed) behavior? AFAIK, yes, it is. To be more precise : we have 'foo' and '.foo' for a function foo(), where 'foo' points to the function_entry and '.foo' points to the actual function. Ah, I see. So if we run func_ptr p = foo; return p == kallsyms_lookup_name(.foo); it returns true. One more thing I should know, is the address of .function_name within the kernel text? In other words, does kernel_text_address() return true for that address? If not, it's easy to verify the address. Thank you, -- Masami HIRAMATSU Software Platform Research Dept. Linux Technology Research Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: masami.hiramatsu...@hitachi.com -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: Re: Re: [RFT PATCH -next v3] [BUGFIX] kprobes: Fix Failed to find blacklist error on ia64 and ppc64
On Thu, 2014-06-19 at 20:20 +0900, Masami Hiramatsu wrote: (2014/06/19 20:01), Masami Hiramatsu wrote: Ah, those messages should be shown in dmesg when booting if it doesn't work, because the messages are printed by initialization process of kprobe blacklist. So, reproducing it is just enabling CONFIG_KPROBES and boot it. Well, we don't get those messages on Power, since the kallsyms has the entries for .function_name. The correct way to verify is, either : Hmm, that seems another issue on powerpc. Is that expected(and designed) behavior? AFAIK, yes, it is. To be more precise : we have 'foo' and '.foo' for a function foo(), where 'foo' points to the function_entry and '.foo' points to the actual function. Ah, I see. So if we run func_ptr p = foo; return p == kallsyms_lookup_name(.foo); it returns true. One more thing I should know, is the address of .function_name within the kernel text? In other words, does kernel_text_address() return true for that address? If not, it's easy to verify the address. Yes. That is the text address, kernel_text_address() should definitely return true. On 64-bit, ABIv1, foo points to the function descriptor, in the .opd section. .foo points to the actual text of the function, in .text. On 64-bit, ABIv2, foo points to the text in .text. There are no dot symbols. cheers -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: Re: [RFT PATCH -next v3] [BUGFIX] kprobes: Fix "Failed to find blacklist" error on ia64 and ppc64
On Wed, 2014-06-18 at 17:46 +0900, Masami Hiramatsu wrote:
> (2014/06/18 16:56), Michael Ellerman wrote:
> > On Fri, 2014-06-06 at 15:38 +0900, Masami Hiramatsu wrote:
> >> Ping?
> >>
> >> I guess this should go to 3.16 branch, shouldn't it?
> >
> >>> diff --git a/arch/powerpc/include/asm/types.h
> >>> b/arch/powerpc/include/asm/types.h
> >>> index bfb6ded..8b89d65 100644
> >>> --- a/arch/powerpc/include/asm/types.h
> >>> +++ b/arch/powerpc/include/asm/types.h
> >>> @@ -25,6 +25,17 @@ typedef struct {
> >>> unsigned long env;
> >>> } func_descr_t;
> >>>
> >>> +#if defined(CONFIG_PPC64) && (!defined(_CALL_ELF) || _CALL_ELF == 1)
> >>> +/*
> >>> + * On PPC64 ABIv1 the function pointer actually points to the
> >>> + * function's descriptor. The first entry in the descriptor is the
> >>> + * address of the function text.
> >>> + */
> >>> +#define function_entry(fn) (((func_descr_t *)(fn))->entry)
> >>> +#else
> >>> +#define function_entry(fn) ((unsigned long)(fn))
> >>> +#endif
> >
> > We already have ppc_function_entry(), can't you use that?
>
> I'd like to ask you whether the address which ppc_function_entry() returns on
> PPC ABIv2 is really same address in kallsyms or not.
> As you can see, kprobes uses function_entry() to get the actual entry address
> where kallsyms knows. I have not much information about that, but it seems
> that
> the "global entry point" is the address which kallsyms knows, isn't it?
OK. I'm not sure off the top of my head which address kallsyms knows about, but
yes it's likely that it is the global entry point.
I recently sent a patch to add ppc_global_function_entry(), because we need it
in the ftrace code. Once that is merged you could use that.
How do you hit the original problem, you don't actually specify in your commit
message? Something with kprobes obviously, but what exactly? I'll try and
reproduce it here.
cheers
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: Re: [RFT PATCH -next v3] [BUGFIX] kprobes: Fix "Failed to find blacklist" error on ia64 and ppc64
(2014/06/18 16:56), Michael Ellerman wrote:
> On Fri, 2014-06-06 at 15:38 +0900, Masami Hiramatsu wrote:
>> Ping?
>>
>> I guess this should go to 3.16 branch, shouldn't it?
>
>>> diff --git a/arch/powerpc/include/asm/types.h
>>> b/arch/powerpc/include/asm/types.h
>>> index bfb6ded..8b89d65 100644
>>> --- a/arch/powerpc/include/asm/types.h
>>> +++ b/arch/powerpc/include/asm/types.h
>>> @@ -25,6 +25,17 @@ typedef struct {
>>> unsigned long env;
>>> } func_descr_t;
>>>
>>> +#if defined(CONFIG_PPC64) && (!defined(_CALL_ELF) || _CALL_ELF == 1)
>>> +/*
>>> + * On PPC64 ABIv1 the function pointer actually points to the
>>> + * function's descriptor. The first entry in the descriptor is the
>>> + * address of the function text.
>>> + */
>>> +#define function_entry(fn) (((func_descr_t *)(fn))->entry)
>>> +#else
>>> +#define function_entry(fn) ((unsigned long)(fn))
>>> +#endif
>
> We already have ppc_function_entry(), can't you use that?
I'd like to ask you whether the address which ppc_function_entry() returns on
PPC ABIv2 is really same address in kallsyms or not.
As you can see, kprobes uses function_entry() to get the actual entry address
where kallsyms knows. I have not much information about that, but it seems that
the "global entry point" is the address which kallsyms knows, isn't it?
Thank you,
--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu...@hitachi.com
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Re: Re: [RFT PATCH -next v3] [BUGFIX] kprobes: Fix Failed to find blacklist error on ia64 and ppc64
(2014/06/18 16:56), Michael Ellerman wrote:
On Fri, 2014-06-06 at 15:38 +0900, Masami Hiramatsu wrote:
Ping?
I guess this should go to 3.16 branch, shouldn't it?
diff --git a/arch/powerpc/include/asm/types.h
b/arch/powerpc/include/asm/types.h
index bfb6ded..8b89d65 100644
--- a/arch/powerpc/include/asm/types.h
+++ b/arch/powerpc/include/asm/types.h
@@ -25,6 +25,17 @@ typedef struct {
unsigned long env;
} func_descr_t;
+#if defined(CONFIG_PPC64) (!defined(_CALL_ELF) || _CALL_ELF == 1)
+/*
+ * On PPC64 ABIv1 the function pointer actually points to the
+ * function's descriptor. The first entry in the descriptor is the
+ * address of the function text.
+ */
+#define function_entry(fn) (((func_descr_t *)(fn))-entry)
+#else
+#define function_entry(fn) ((unsigned long)(fn))
+#endif
We already have ppc_function_entry(), can't you use that?
I'd like to ask you whether the address which ppc_function_entry() returns on
PPC ABIv2 is really same address in kallsyms or not.
As you can see, kprobes uses function_entry() to get the actual entry address
where kallsyms knows. I have not much information about that, but it seems that
the global entry point is the address which kallsyms knows, isn't it?
Thank you,
--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu...@hitachi.com
--
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the body of a message to majord...@vger.kernel.org
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Please read the FAQ at http://www.tux.org/lkml/
Re: Re: [RFT PATCH -next v3] [BUGFIX] kprobes: Fix Failed to find blacklist error on ia64 and ppc64
On Wed, 2014-06-18 at 17:46 +0900, Masami Hiramatsu wrote:
(2014/06/18 16:56), Michael Ellerman wrote:
On Fri, 2014-06-06 at 15:38 +0900, Masami Hiramatsu wrote:
Ping?
I guess this should go to 3.16 branch, shouldn't it?
diff --git a/arch/powerpc/include/asm/types.h
b/arch/powerpc/include/asm/types.h
index bfb6ded..8b89d65 100644
--- a/arch/powerpc/include/asm/types.h
+++ b/arch/powerpc/include/asm/types.h
@@ -25,6 +25,17 @@ typedef struct {
unsigned long env;
} func_descr_t;
+#if defined(CONFIG_PPC64) (!defined(_CALL_ELF) || _CALL_ELF == 1)
+/*
+ * On PPC64 ABIv1 the function pointer actually points to the
+ * function's descriptor. The first entry in the descriptor is the
+ * address of the function text.
+ */
+#define function_entry(fn) (((func_descr_t *)(fn))-entry)
+#else
+#define function_entry(fn) ((unsigned long)(fn))
+#endif
We already have ppc_function_entry(), can't you use that?
I'd like to ask you whether the address which ppc_function_entry() returns on
PPC ABIv2 is really same address in kallsyms or not.
As you can see, kprobes uses function_entry() to get the actual entry address
where kallsyms knows. I have not much information about that, but it seems
that
the global entry point is the address which kallsyms knows, isn't it?
OK. I'm not sure off the top of my head which address kallsyms knows about, but
yes it's likely that it is the global entry point.
I recently sent a patch to add ppc_global_function_entry(), because we need it
in the ftrace code. Once that is merged you could use that.
How do you hit the original problem, you don't actually specify in your commit
message? Something with kprobes obviously, but what exactly? I'll try and
reproduce it here.
cheers
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