[PATCH v2 1/6] kselftest/arm64: mte: user_mem: introduce tag_offset and tag_len

[Shuah Khan]

On 2/3/22 7:36 AM, Joey Gouly wrote:
> These can be used to place a different tag not at a page size boundary.

Please add more information here. Based on the code instead of pagesz, this
test allows other sizes. This is a good change and bit more info. helps
describe the value of this change.

> 
> Signed-off-by: Joey Gouly <joey.gouly at arm.com>
> Cc: Catalin Marinas <catalin.marinas at arm.com>
> Cc: Will Deacon <will at kernel.org>
> Cc: Mark Brown <broonie at kernel.org>
> Cc: Shuah Khan <shuah at kernel.org>
> ---
>   .../selftests/arm64/mte/check_user_mem.c      | 19 +++++++++++--------
>   1 file changed, 11 insertions(+), 8 deletions(-)
> 
> diff --git a/tools/testing/selftests/arm64/mte/check_user_mem.c b/tools/testing/selftests/arm64/mte/check_user_mem.c
> index 1de7a0abd0ae..5a5a7e1f5789 100644
> --- a/tools/testing/selftests/arm64/mte/check_user_mem.c
> +++ b/tools/testing/selftests/arm64/mte/check_user_mem.c
> @@ -19,7 +19,8 @@
>   
>   static size_t page_sz;
>   
> -static int check_usermem_access_fault(int mem_type, int mode, int mapping)
> +static int check_usermem_access_fault(int mem_type, int mode, int mapping,
> +                                      int tag_offset, int tag_len)
>   {
>   	int fd, i, err;
>   	char val = 'A';
> @@ -54,10 +55,12 @@ static int check_usermem_access_fault(int mem_type, int mode, int mapping)
>   	if (i < len)
>   		goto usermem_acc_err;
>   
> -	/* Tag the next half of memory with different value */
> -	ptr_next = (void *)((unsigned long)ptr + page_sz);
> +	if (!tag_len)
> +		tag_len = len - tag_offset;
> +	/* Tag a part of memory with different value */
> +	ptr_next = (void *)((unsigned long)ptr + tag_offset);
>   	ptr_next = mte_insert_new_tag(ptr_next);
> -	mte_set_tag_address_range(ptr_next, page_sz);
> +	mte_set_tag_address_range(ptr_next, tag_len);
>   
>   	lseek(fd, 0, 0);
>   	/* Copy from file into buffer with invalid tag */
> @@ -100,14 +103,14 @@ int main(int argc, char *argv[])
>   	/* Set test plan */
>   	ksft_set_plan(4);
>   
> -	evaluate_test(check_usermem_access_fault(USE_MMAP, MTE_SYNC_ERR, MAP_PRIVATE),
> +	evaluate_test(check_usermem_access_fault(USE_MMAP, MTE_SYNC_ERR, MAP_PRIVATE, page_sz, 0),
>   		"Check memory access from kernel in sync mode, private mapping and mmap memory\n");

Any reason to not print the size - old message is better?

> -	evaluate_test(check_usermem_access_fault(USE_MMAP, MTE_SYNC_ERR, MAP_SHARED),
> +	evaluate_test(check_usermem_access_fault(USE_MMAP, MTE_SYNC_ERR, MAP_SHARED, page_sz, 0),
>   		"Check memory access from kernel in sync mode, shared mapping and mmap memory\n");
>   
> -	evaluate_test(check_usermem_access_fault(USE_MMAP, MTE_ASYNC_ERR, MAP_PRIVATE),
> +	evaluate_test(check_usermem_access_fault(USE_MMAP, MTE_ASYNC_ERR, MAP_PRIVATE, page_sz, 0),
>   		"Check memory access from kernel in async mode, private mapping and mmap memory\n");
> -	evaluate_test(check_usermem_access_fault(USE_MMAP, MTE_ASYNC_ERR, MAP_SHARED),
> +	evaluate_test(check_usermem_access_fault(USE_MMAP, MTE_ASYNC_ERR, MAP_SHARED, page_sz, 0),
>   		"Check memory access from kernel in async mode, shared mapping and mmap memory\n");
>   
>   	mte_restore_setup();
> 

With these comments:

Reviewed-by: Shuah Khan <skhan at linuxfoundation.org>

thanks,
-- Shuah