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From: Mark Rutland <mark.rutland@arm.com>
To: madvenka@linux.microsoft.com
Cc: broonie@kernel.org, jpoimboe@redhat.com, ardb@kernel.org,
	nobuta.keiya@fujitsu.com, sjitindarsingh@gmail.com,
	catalin.marinas@arm.com, will@kernel.org, jmorris@namei.org,
	linux-arm-kernel@lists.infradead.org,
	live-patching@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v10 06/11] arm64: Make profile_pc() use arch_stack_walk()
Date: Wed, 27 Oct 2021 14:32:12 +0100	[thread overview]
Message-ID: <20211027133212.GG54628@C02TD0UTHF1T.local> (raw)
In-Reply-To: <20211015025847.17694-7-madvenka@linux.microsoft.com>

On Thu, Oct 14, 2021 at 09:58:42PM -0500, madvenka@linux.microsoft.com wrote:
> From: "Madhavan T. Venkataraman" <madvenka@linux.microsoft.com>
> 
> Currently, profile_pc() in ARM64 code walks the stack using
> start_backtrace() and unwind_frame(). Make it use arch_stack_walk()
> instead. This makes maintenance easier.
> 
> Signed-off-by: Madhavan T. Venkataraman <madvenka@linux.microsoft.com>
> ---
>  arch/arm64/kernel/time.c | 22 +++++++++++++---------
>  1 file changed, 13 insertions(+), 9 deletions(-)
> 
> diff --git a/arch/arm64/kernel/time.c b/arch/arm64/kernel/time.c
> index eebbc8d7123e..671b3038a772 100644
> --- a/arch/arm64/kernel/time.c
> +++ b/arch/arm64/kernel/time.c
> @@ -32,22 +32,26 @@
>  #include <asm/stacktrace.h>
>  #include <asm/paravirt.h>
>  
> +static bool profile_pc_cb(void *arg, unsigned long pc)
> +{
> +	unsigned long *prof_pc = arg;
> +
> +	if (in_lock_functions(pc))
> +		return true;
> +	*prof_pc = pc;
> +	return false;
> +}
> +
>  unsigned long profile_pc(struct pt_regs *regs)
>  {
> -	struct stackframe frame;
> +	unsigned long prof_pc = 0;
>  
>  	if (!in_lock_functions(regs->pc))
>  		return regs->pc;

This can go -- the first call to profile_pc_cb() will use regs->pc.

With that gone, and the include updates to use <linux/stacktrace.h>:

Reviewed-by: Mark Rutland <mark.rutland@arm.com>

Mark.

> -	start_backtrace(&frame, regs->regs[29], regs->pc);
> -
> -	do {
> -		int ret = unwind_frame(NULL, &frame);
> -		if (ret < 0)
> -			return 0;
> -	} while (in_lock_functions(frame.pc));
> +	arch_stack_walk(profile_pc_cb, &prof_pc, current, regs);
>  
> -	return frame.pc;
> +	return prof_pc;
>  }
>  EXPORT_SYMBOL(profile_pc);
>  
> -- 
> 2.25.1
> 

  parent reply	other threads:[~2021-10-27 13:32 UTC|newest]

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <c05ce30dcc9be1bd6b5e24a2ca8fe1d66246980b>
2021-10-15  2:34 ` [PATCH v9 00/11] arm64: Reorganize the unwinder and implement stack trace reliability checks madvenka
2021-10-15  2:34   ` [PATCH v9 01/11] arm64: Select STACKTRACE in arch/arm64/Kconfig madvenka
2021-10-15  2:34   ` [PATCH v9 10/11] arm64: Introduce stack trace reliability checks in the unwinder madvenka
2021-10-15  2:34   ` [PATCH v9 11/11] arm64: Create a list of SYM_CODE functions, check return PC against list madvenka
2021-10-15  2:34   ` [PATCH v9 02/11] arm64: Make perf_callchain_kernel() use arch_stack_walk() madvenka
2021-10-15  2:34   ` [PATCH v9 03/11] arm64: Make get_wchan() " madvenka
2021-10-15  2:34   ` [PATCH v9 04/11] arm64: Make return_address() " madvenka
2021-10-15  2:34   ` [PATCH v9 05/11] arm64: Make dump_stacktrace() " madvenka
2021-10-15  2:34   ` [PATCH v9 06/11] arm64: Make profile_pc() " madvenka
2021-10-15  2:34   ` [PATCH v9 07/11] arm64: Call stack_backtrace() only from within walk_stackframe() madvenka
2021-10-15  2:34   ` [PATCH v9 08/11] arm64: Rename unwinder functions, prevent them from being traced and kprobed madvenka
2021-10-15  2:34   ` [PATCH v9 09/11] arm64: Make the unwind loop in unwind() similar to other architectures madvenka
2021-10-15  2:53   ` [PATCH v9 00/11] arm64: Reorganize the unwinder and implement stack trace reliability checks Madhavan T. Venkataraman
2021-10-15  2:58 ` [PATCH v10 " madvenka
2021-10-15  2:58   ` [PATCH v10 01/11] arm64: Select STACKTRACE in arch/arm64/Kconfig madvenka
2021-10-15 18:28     ` Mark Brown
2021-10-21 12:28       ` Madhavan T. Venkataraman
2021-10-22 18:02     ` Mark Rutland
2021-11-12 17:44       ` Mark Rutland
2021-11-14 16:15         ` Madhavan T. Venkataraman
2021-10-15  2:58   ` [PATCH v10 02/11] arm64: Make perf_callchain_kernel() use arch_stack_walk() madvenka
2021-10-20 14:59     ` Mark Brown
2021-10-21 12:28       ` Madhavan T. Venkataraman
2021-10-22 18:11     ` Mark Rutland
2021-10-23 12:49       ` Madhavan T. Venkataraman
2021-10-15  2:58   ` [PATCH v10 03/11] arm64: Make get_wchan() " madvenka
2021-10-20 16:10     ` Mark Brown
2021-10-21 12:30       ` Madhavan T. Venkataraman
2021-10-15  2:58   ` [PATCH v10 04/11] arm64: Make return_address() " madvenka
2021-10-20 15:03     ` Mark Brown
2021-10-21 12:29       ` Madhavan T. Venkataraman
2021-10-22 18:51     ` Mark Rutland
2021-10-23 12:51       ` Madhavan T. Venkataraman
2021-10-15  2:58   ` [PATCH v10 05/11] arm64: Make dump_stacktrace() " madvenka
2021-10-25 16:49     ` Mark Rutland
2021-10-26 12:05       ` Mark Rutland
2021-10-27 16:09         ` Madhavan T. Venkataraman
2021-10-15  2:58   ` [PATCH v10 06/11] arm64: Make profile_pc() " madvenka
2021-10-25  2:18     ` nobuta.keiya
2021-10-27 16:10       ` Madhavan T. Venkataraman
2021-10-27 13:32     ` Mark Rutland [this message]
2021-10-27 16:15       ` Madhavan T. Venkataraman
2021-10-15  2:58   ` [PATCH v10 07/11] arm64: Call stack_backtrace() only from within walk_stackframe() madvenka
2021-10-15  2:58   ` [PATCH v10 08/11] arm64: Rename unwinder functions, prevent them from being traced and kprobed madvenka
2021-10-27 17:53     ` Mark Rutland
2021-10-27 20:07       ` Madhavan T. Venkataraman
2021-10-15  2:58   ` [PATCH v10 09/11] arm64: Make the unwind loop in unwind() similar to other architectures madvenka
2021-10-15  2:58   ` [PATCH v10 10/11] arm64: Introduce stack trace reliability checks in the unwinder madvenka
2021-11-04 12:39     ` nobuta.keiya
2021-11-10  3:13       ` Madhavan T. Venkataraman
2021-10-15  2:58   ` [PATCH v10 11/11] arm64: Create a list of SYM_CODE functions, check return PC against list madvenka
2021-10-15 17:00   ` [PATCH v10 00/11] arm64: Reorganize the unwinder and implement stack trace reliability checks Madhavan T. Venkataraman

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