2022-04-28 14:03:01

by Greg Kroah-Hartman

Subject: Re: [PATCHv12 7/9] asm-generic/io: Add logging support for MMIO accessors

On Thu, Apr 28, 2022 at 03:25:30PM +0530, Sai Prakash Ranjan wrote:
> Add logging support for MMIO high level accessors such as read{b,w,l,q}
> and their relaxed versions to aid in debugging unexpected crashes/hangs
> caused by the corresponding MMIO operation.
>
> Signed-off-by: Sai Prakash Ranjan <[email protected]>
> ---
> include/asm-generic/io.h | 82 ++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 78 insertions(+), 4 deletions(-)
>
> diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h
> index 7ce93aaf69f8..99090722cb4b 100644
> --- a/include/asm-generic/io.h
> +++ b/include/asm-generic/io.h
> @@ -10,6 +10,7 @@
> #include <asm/page.h> /* I/O is all done through memory accesses */
> #include <linux/string.h> /* for memset() and memcpy() */
> #include <linux/types.h>
> +#include <linux/instruction_pointer.h>
>
> #ifdef CONFIG_GENERIC_IOMAP
> #include <asm-generic/iomap.h>
> @@ -61,6 +62,35 @@
> #define __io_par(v) __io_ar(v)
> #endif
>
> +#if IS_ENABLED(CONFIG_TRACE_MMIO_ACCESS) && !(defined(__DISABLE_TRACE_MMIO__))

Shouldn't you document __DISABLE_TRACE_MMIO__ somewhere? It's not even
in the changelog. Put a big comment above this for what is is for and
how to use it. Otherwise you will forget all about this in 6 months :)

thanks,

greg k-h

2022-04-29 22:00:56

by Sai Prakash Ranjan

Subject: Re: [PATCHv12 7/9] asm-generic/io: Add logging support for MMIO accessors

On 4/28/2022 4:21 PM, Greg KH wrote:
> On Thu, Apr 28, 2022 at 03:25:30PM +0530, Sai Prakash Ranjan wrote:
>> Add logging support for MMIO high level accessors such as read{b,w,l,q}
>> and their relaxed versions to aid in debugging unexpected crashes/hangs
>> caused by the corresponding MMIO operation.
>>
>> Signed-off-by: Sai Prakash Ranjan <[email protected]>
>> ---
>> include/asm-generic/io.h | 82 ++++++++++++++++++++++++++++++++++++++--
>> 1 file changed, 78 insertions(+), 4 deletions(-)
>>
>> diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h
>> index 7ce93aaf69f8..99090722cb4b 100644
>> --- a/include/asm-generic/io.h
>> +++ b/include/asm-generic/io.h
>> @@ -10,6 +10,7 @@
>> #include <asm/page.h> /* I/O is all done through memory accesses */
>> #include <linux/string.h> /* for memset() and memcpy() */
>> #include <linux/types.h>
>> +#include <linux/instruction_pointer.h>
>>
>> #ifdef CONFIG_GENERIC_IOMAP
>> #include <asm-generic/iomap.h>
>> @@ -61,6 +62,35 @@
>> #define __io_par(v) __io_ar(v)
>> #endif
>>
>> +#if IS_ENABLED(CONFIG_TRACE_MMIO_ACCESS) && !(defined(__DISABLE_TRACE_MMIO__))
> Shouldn't you document __DISABLE_TRACE_MMIO__ somewhere? It's not even
> in the changelog. Put a big comment above this for what is is for and
> how to use it. Otherwise you will forget all about this in 6 months :)
>
> thanks,
>
> greg k-h

Didn't you ask me to split the patch to the one actually adding the flag and the one using it.
So I have added the description in that patch which adds the flag since we can't add description
everywhere we use the flag right :)

Thanks,
Sai