From: Will Deacon <will.deacon@arm.com>
To: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Cc: Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@redhat.com>, Laura Abbott <labbott@redhat.com>,
Kees Cook <keescook@chromium.org>,
Anton Vorontsov <anton@enomsg.org>,
Colin Cross <ccross@android.com>, Jason Baron <jbaron@akamai.com>,
Tony Luck <tony.luck@intel.com>, Arnd Bergmann <arnd@arndb.de>,
Catalin Marinas <catalin.marinas@arm.com>,
Joel Fernandes <joel@joelfernandes.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Joe Perches <joe@perches.com>, Jim Cromie <jim.cromie@gmail.com>,
Rajendra Nayak <rnayak@codeaurora.org>,
Vivek Gautam <vivek.gautam@codeaurora.org>,
Sibi Sankar <sibis@codeaurora.org>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Ingo Molnar <mingo@kernel.org>,
Tom Zanussi <tom.zanussi@linux.intel.com>
Subject: Re: [RFC PATCH v2 3/3] dynamic_debug: Add support for dynamic register trace
Date: Thu, 6 Sep 2018 11:05:24 +0100 [thread overview]
Message-ID: <20180906100523.GE3592@arm.com> (raw)
In-Reply-To: <9015a7a4aafa9935be769c07918743df63d6f648.1535119711.git.saiprakash.ranjan@codeaurora.org>
On Fri, Aug 24, 2018 at 08:15:27PM +0530, Sai Prakash Ranjan wrote:
> Introduce dynamic debug filtering mechanism to register
> tracing as dynamic_rtb() which will reduce a lot of
> overhead otherwise of tracing all the register reads/writes
> in all files.
>
> Now we can just specify the file name or any wildcard pattern
> as any other dynamic debug facility in bootargs and dynamic rtb
> will just trace them and the output can be seen in pstore.
>
> TODO: Now we use same 'p' flag but will add a separate flag for register trace
> later.
>
> Also add asm-generic/io-instrumented.h file for instrumentation of IO
> operations such as read/write{b,w,l,q} as per Will's suggestion to not touch
> arch code and let core generate instrumentation.
> This can be extended to arm as well later for tracing.
>
> Example for tracing all register reads/writes in drivers/soc/qcom/* below:
>
> # dyndbg="file drivers/soc/qcom/* +p" in bootargs
> # reboot -f
> # mount -t pstore pstore /sys/fs/pstore
> # cat /sys/fs/pstore/rtb-ramoops-0
> [LOGK_WRITE] ts:1373030419 data:ffff00000d5065a4 <ffff00000867cb44> qcom_smsm_probe+0x51c/0x668
> [LOGK_WRITE] ts:1373360576 data:ffff00000d506608 <ffff00000867cb44> qcom_smsm_probe+0x51c/0x668
>
> Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
> ---
> arch/arm64/include/asm/io.h | 26 +++++++++-------------
> include/asm-generic/io-instrumented.h | 32 +++++++++++++++++++++++++++
> include/linux/dynamic_debug.h | 13 +++++++++++
> kernel/trace/Kconfig | 1 +
> 4 files changed, 56 insertions(+), 16 deletions(-)
> create mode 100644 include/asm-generic/io-instrumented.h
>
> diff --git a/arch/arm64/include/asm/io.h b/arch/arm64/include/asm/io.h
> index 35b2e50f17fb..aafd4b0be9f0 100644
> --- a/arch/arm64/include/asm/io.h
> +++ b/arch/arm64/include/asm/io.h
The arm64 bits look fine to me, but please can you split them into a
separate patch?
> diff --git a/include/asm-generic/io-instrumented.h b/include/asm-generic/io-instrumented.h
> new file mode 100644
> index 000000000000..ce273742b98c
> --- /dev/null
> +++ b/include/asm-generic/io-instrumented.h
> @@ -0,0 +1,32 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +
> +#ifndef _ASM_GENERIC_IO_INSTRUMENTED_H
> +#define _ASM_GENERIC_IO_INSTRUMENTED_H
> +
> +#include <linux/dynamic_debug.h>
> +
> +#define __raw_write(v, a, _t) ({ \
> + volatile void __iomem *_a = (a); \
Does this actually need to be volatile?
> + dynamic_rtb("LOGK_WRITE", (void __force *)(_a));\
> + arch_raw_write##_t((v), _a); \
> + })
> +
> +#define __raw_writeb(v, a) __raw_write((v), a, b)
> +#define __raw_writew(v, a) __raw_write((v), a, w)
> +#define __raw_writel(v, a) __raw_write((v), a, l)
> +#define __raw_writeq(v, a) __raw_write((v), a, q)
> +
> +#define __raw_read(a, _l, _t) ({ \
> + _t __a; \
> + const volatile void __iomem *_a = (const volatile void __iomem *)(a);\
Again, can't this just be void __iomem * ?
> + dynamic_rtb("LOGK_READ", (void __force *)(_a)); \
> + __a = arch_raw_read##_l(_a); \
> + __a; \
> + })
> +
> +#define __raw_readb(a) __raw_read((a), b, u8)
> +#define __raw_readw(a) __raw_read((a), w, u16)
> +#define __raw_readl(a) __raw_read((a), l, u32)
> +#define __raw_readq(a) __raw_read((a), q, u64)
I find the way you've defined the __raw_{read,write} macros quite confusing.
They both have an _t parameter, but it's totally unrelated between the two!
Will
next prev parent reply other threads:[~2018-09-06 10:05 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-24 14:45 [RFC PATCH v2 0/3] Register read/write tracing with dynamic debug and pstore Sai Prakash Ranjan
2018-08-24 14:45 ` [RFC PATCH v2 1/3] tracing: Add support for logging data to uncached buffer Sai Prakash Ranjan
2018-08-24 14:45 ` [RFC PATCH v2 2/3] pstore: Add register read/write{b,w,l,q} tracing support Sai Prakash Ranjan
2018-08-24 15:29 ` Kees Cook
2018-08-25 7:24 ` Sai Prakash Ranjan
2018-08-27 16:15 ` Steven Rostedt
2018-08-28 13:17 ` Sai Prakash Ranjan
2018-08-28 16:02 ` Steven Rostedt
2018-08-28 17:26 ` Sai Prakash Ranjan
2018-08-24 14:45 ` [RFC PATCH v2 3/3] dynamic_debug: Add support for dynamic register trace Sai Prakash Ranjan
2018-09-06 10:05 ` Will Deacon [this message]
2018-09-06 18:06 ` Sai Prakash Ranjan
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