Re: [PATCH v3 2/7] gdb: aarch64: Move MTE address check out of set_memtag

[Gustavo Romero <gustavo.romero@linaro.org>]

Hi Luis,

On 4/4/24 11:17 AM, Luis Machado wrote:
> On 4/4/24 07:48, Gustavo Romero wrote:
>> Move MTE address check out of set_memtag and add this check to the
>> upper layer, before set_memtag is called. This is a preparation for
>> using a target hook instead of a gdbarch hook MTE address checks.
>>
>> Signed-off-by: Gustavo Romero <gustavo.romero@linaro.org>
>> ---
>>   gdb/aarch64-linux-tdep.c | 4 ----
>>   gdb/printcmd.c           | 5 +++++
>>   2 files changed, 5 insertions(+), 4 deletions(-)
>>
>> diff --git a/gdb/aarch64-linux-tdep.c b/gdb/aarch64-linux-tdep.c
>> index 50055ac3f48..8e6e63d4dcb 100644
>> --- a/gdb/aarch64-linux-tdep.c
>> +++ b/gdb/aarch64-linux-tdep.c
>> @@ -2525,10 +2525,6 @@ aarch64_linux_set_memtags (struct gdbarch *gdbarch, struct value *address,
>>         /* Remove the top byte.  */
>>         addr = gdbarch_remove_non_address_bits (gdbarch, addr);
>>   
>> -      /* Make sure we are dealing with a tagged address to begin with.  */
>> -      if (!aarch64_linux_tagged_address_p (gdbarch, address))
>> -	return false;
>> -
>>         /* With G being the number of tag granules and N the number of tags
>>   	 passed in, we can have the following cases:
>>   
>> diff --git a/gdb/printcmd.c b/gdb/printcmd.c
>> index cb0d32aa4bc..774e3ec74ae 100644
>> --- a/gdb/printcmd.c
>> +++ b/gdb/printcmd.c
>> @@ -3127,6 +3127,11 @@ memory_tag_set_allocation_tag_command (const char *args, int from_tty)
>>     /* Parse the input.  */
>>     parse_set_allocation_tag_input (args, &val, &length, tags);
>>   
>> +  /* If the address is not in a region memory mapped with a memory tagging
> 
> A nit:
> 
> s/memory mapped/memory-mapped ?
> 
>> +     flag, it is no use trying to manipulate its allocation tag.  */
>> +  if (!gdbarch_tagged_address_p (current_inferior ()->arch (), val))
>> +    show_addr_not_tagged (value_as_address(val));
>> +
> 
> Looks like memory_tag_set_allocation_tag_command calls parse_set_allocation_tag_input,
> and the latter has the exact same check as you are adding here. Is this then redundant?

hmm, right, it is (and was) redundant. I'm removing the check from parse_set_allocation_tag_input.


Thanks,
Gustavo