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@xxxxxxxxxxxxxx>
> ---
> 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
