From: will.deacon@arm•com (Will Deacon)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v2 2/7] ARM: Introduce arm_get_current_stack_frame()
Date: Fri, 30 May 2014 18:20:54 +0100 [thread overview]
Message-ID: <20140530172054.GE22895@arm.com> (raw)
In-Reply-To: <1401469191-29232-3-git-send-email-nikolay.borisov@arm.com>
On Fri, May 30, 2014 at 05:59:46PM +0100, Nikolay Borisov wrote:
> From: Nikolay Borisov <Nikolay.Borisov@arm•com>
>
> Currently there are numerous places where "struct pt_regs" are used to
> populate "struct stackframe", however all of those location do not
> consider the situation where the kernel might be compiled in THUMB2
> mode, in which case the framepointer member of pt_regs become ARM_r7
> instead of ARM_fp (r11). Document this idiosyncracy in the
> definition of "struct stackframe"
>
> The easiest solution is to introduce a new function (in the spirit of
> https://groups.google.com/forum/#!topic/linux.kernel/dA2YuUcSpZ4)
> which would hide the complexity of initializing the stackframe struct
> from pt_regs.
>
> Also implement a macro frame_pointer(regs) that would return the correct
> register so that we can use it in cases where we just require the frame
> pointer and not a whole struct stackframe
>
> Signed-off-by: Nikolay Borisov <Nikolay.Borisov@arm•com>
> ---
> arch/arm/include/asm/ptrace.h | 6 ++++++
> arch/arm/include/asm/stacktrace.h | 12 ++++++++++++
> 2 files changed, 18 insertions(+)
>
> diff --git a/arch/arm/include/asm/ptrace.h b/arch/arm/include/asm/ptrace.h
> index c877654..601264d 100644
> --- a/arch/arm/include/asm/ptrace.h
> +++ b/arch/arm/include/asm/ptrace.h
> @@ -84,6 +84,12 @@ static inline long regs_return_value(struct pt_regs *regs)
>
> #define instruction_pointer(regs) (regs)->ARM_pc
>
> +#ifdef CONFIG_THUMB2_KERNEL
> +#define frame_pointer(regs) (regs)->ARM_r7
> +#else
> +#define frame_pointer(regs) (regs)->ARM_fp
> +#endif
> +
> static inline void instruction_pointer_set(struct pt_regs *regs,
> unsigned long val)
> {
> diff --git a/arch/arm/include/asm/stacktrace.h b/arch/arm/include/asm/stacktrace.h
> index 4d0a164..6a5b13e 100644
> --- a/arch/arm/include/asm/stacktrace.h
> +++ b/arch/arm/include/asm/stacktrace.h
> @@ -2,12 +2,24 @@
> #define __ASM_STACKTRACE_H
>
> struct stackframe {
> + /* FP member should hold R7 when CONFIG_THUMB2_KERNEL is enabled.
> + * and R11 otherwise
> + */
Very minor nit: please reformat the comment like:
/*
* FP member should hold R7 when CONFIG_THUMB2_KERNEL is enabled
* and R11 otherwise.
*/
for consistency with the rest of the kernel (I also moved the full-stop to
the end of the sentence).
With that:
Acked-by: Will Deacon <will.deacon@arm•com>
Will
next prev parent reply other threads:[~2014-05-30 17:20 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-30 16:59 [PATCH v2 0/7] Fix backtrace support in THUMB2 mode Nikolay Borisov
2014-05-30 16:59 ` [PATCH v2 1/7] ARM: Make thread_save_fp macro aware of " Nikolay Borisov
2014-05-30 16:59 ` [PATCH v2 2/7] ARM: Introduce arm_get_current_stack_frame() Nikolay Borisov
2014-05-30 17:20 ` Will Deacon [this message]
2014-06-02 8:05 ` Robert Richter
2014-05-30 16:59 ` [PATCH v3 3/7] ARM: perf: Make perf use arm_get_current_stackframe Nikolay Borisov
2014-05-30 16:59 ` [PATCH v2 4/7] ARM: time: Make use of arm_get_current_stackframe Nikolay Borisov
2014-05-30 16:59 ` [PATCH v2 5/7] ARM: unwind: Use arm_get_current_stackframe Nikolay Borisov
2014-05-30 16:59 ` [PATCH v2 6/7] ARM: traps: Make use of the frame_pointer macro Nikolay Borisov
2014-05-30 16:59 ` [PATCH v2 7/7] ARM: oprofile: Use of arm_get_current_stackframe Nikolay Borisov
2014-05-30 17:19 ` [PATCH v2 0/7] Fix backtrace support in THUMB2 mode Will Deacon
2014-05-31 18:31 ` Arnd Bergmann
2014-06-02 8:34 ` Nikolay Borisov
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