Re: [PATCH v3 24/24] Add memory tagging testcases

[Luis Machado via Gdb-patches <gdb-patches@sourceware.org>]

On 12/27/20 1:36 AM, Simon Marchi wrote:
> 
> 
> On 2020-11-09 12:04 p.m., Luis Machado via Gdb-patches wrote:
>> +# Targets that don't support memory tagging should not execute the
>> +# runtime memory tagging tests.
>> +if {![supports_memtag]} {
>> +    untested "memory tagging unsupported"
> 
> Use unsupported?
>  > https://www.gnu.org/software/dejagnu/manual/unsupported-procedure.html
> 

Fixed.

>> +    return -1
>> +}
>> +
>> +gdb_breakpoint "access_memory"
>> +
>> +if [gdb_continue "access_memory"] {
>> +    fail "could not run to tagged memory test function"
> 
> gdb_continue will already produce a FAIL, so no need to use another one here.
> 

Thanks for spotting this. Fixed now.

>> +    return -1
>> +}
>> +
>> +# Fetch a known pointer to an area mapped with PROT_MTE.
>> +set tagged_ptr_symbol "tagged_ptr"
>> +set tagged_ptr_addr [get_hexadecimal_valueof $tagged_ptr_symbol -1]
>> +
>> +if {$tagged_ptr_addr == -1} {
>> +    untested "unexpected pointer or tag value"
> 
> If that happens, that would be an expected error in the test that should be
> fixed, right?  If so, I'd suggest using "unresolved".  We should be able to
> get that value, if we can't something is wrong (it's not just a matter of
> something being unsupported).
> 

That's true. If that happens, all the bets are off, and we don't want to 
continue the test.

>> +    return -1
>> +}
>> +
>> +# Fetch a known pointer to an area not mapped with PROT_MTE.
>> +set untagged_ptr_symbol "untagged_ptr"
>> +set untagged_ptr_addr [get_hexadecimal_valueof $untagged_ptr_symbol -1]
>> +
>> +if {$untagged_ptr_addr == -1} {
>> +    untested "unexpected pointer or tag value"
> 
> Same here.
> 

Fixed.

>> +with_test_prefix "symbolic" {
>> +    # Test inspecting an allocation tag from a pointer to a memory area that
>> +    # is not mapped with PROT_MTE.
>> +    set msg "Address ${untagged_ptr_addr} not in a region mapped with a memory tagging flag\."
>> +    gdb_test "mtag showatag ${untagged_ptr_symbol}" $msg \
>> +	     "mtag showatag with an untagged address"
>> +
>> +    gdb_test "mtag setatag ${untagged_ptr_symbol} 0 00" $msg \
>> +	     "mtag setatag with an untagged address"
>> +
>> +    # Test setting and showing the logical tags for a literal address.
>> +    for {set i 0} {$i < 32} {incr i} {
>> +	set addr_tagged 0
>> +
>> +	with_test_prefix "tag ${i}" {
>> +	    set addr_tagged [get_tagged_ptr $i ${tagged_ptr_addr}]
>> +	    gdb_test_no_output "set variable ${tagged_ptr_symbol} = ${addr_tagged}" \
>> +			       "update value of symbol ${tagged_ptr_symbol}"
>> +	}
>> +
>> +	set tag_hexnz [get_hex_tag [expr $i % 16]]
>> +	gdb_test "mtag showltag ${tagged_ptr_symbol}" \
>> +		 " = 0x${tag_hexnz}" \
>> +		 "showltag with tag ${i}"
>> +
>> +	set tag_hexnn [get_tag_nn $i]
>> +	gdb_test "mtag withltag ${tagged_ptr_symbol} ${tag_hexnn}" \
>> +		 " = \\(void \\*\\) ${addr_tagged}" \
>> +		 "withltag with tag ${i}"
>> +    }
>> +
>> +    # Reset the tagged ptr to its original value
>> +    gdb_test_no_output "set variable ${tagged_ptr_symbol} = ${tagged_ptr_addr}" \
>> +		       "reset ${tagged_ptr_symbol} to ${tagged_ptr_addr}"
>> +
>> +    set setatag_msg "Allocation tag\\(s\\) updated successfully\."
>> +    # Test setting and showing the allocation tags.
>> +    for {set i 0} {$i < 32} {incr i} {
>> +
>> +	set tag_hexnn [get_tag_nn $i]
>> +	gdb_test "mtag setatag ${tagged_ptr_symbol} 0 ${tag_hexnn}" \
>> +		 $setatag_msg \
>> +		 "setatag with tag ${i}"
>> +
>> +	set tag_hexnz [get_hex_tag [expr $i % 16]]
>> +	gdb_test "mtag showatag ${tagged_ptr_symbol}" " = 0x${tag_hexnz}" \
>> +		 "showatag with tag ${i}"
>> +    }
>> +
>> +    # Test tag mismatches.
>> +    with_test_prefix "tag mismatches" {
>> +	for {set i 0} {$i < 32} {incr i} {
>> +
>> +	    # Set the allocation tag to a known value (0).
>> +	    set tag_hexnn [get_tag_nn $i]
>> +	    gdb_test "mtag setatag ${tagged_ptr_symbol} 0 ${tag_hexnn}" \
>> +		     $setatag_msg \
>> +		     "setatag with tag ${i}"
>> +
>> +	    set atag_hexnz [get_hex_tag [expr $i % 16]]
>> +
>> +	    # Validate that the logical tag matches the allocation tag.
>> +	    with_test_prefix "tag ${i}" {
>> +		set addr_tagged [get_tagged_ptr $i ${tagged_ptr_addr}]
>> +	    }
>> +
>> +	    with_test_prefix "tag ${i}" {
>> +		gdb_test_no_output "set variable ${tagged_ptr_symbol} = ${addr_tagged}" \
>> +				   "set ${tagged_ptr_symbol} to a matching logical tag"
>> +	    }
>> +
>> +	    gdb_test "mtag check ${tagged_ptr_symbol}" \
>> +		     "Memory tags for address $hex match \\(0x${atag_hexnz}\\)\." \
>> +		     "check match with tag ${i}"
>> +
>> +	    # Get a pointer with the logical tag that does not match the
>> +	    # allocation tag.
>> +	    set ltag [expr $i + 1]
>> +	    with_test_prefix "fetch mismatch tag ${i}" {
>> +		set addr_tagged [get_tagged_ptr $ltag ${tagged_ptr_addr}]
>> +	    }
>> +
>> +	    with_test_prefix "tag ${i}" {
>> +		gdb_test_no_output "set variable ${tagged_ptr_symbol} = ${addr_tagged}" \
>> +				   "set ${tagged_ptr_symbol} to a mismatching logical tag"
>> +	    }
>> +
>> +	    # Validate that the logical tag does not match the allocation
>> +	    # tag.
>> +	    set ltag_hexnz [get_hex_tag [expr [expr $i + 1]% 16]]
>> +	    gdb_test "mtag check ${tagged_ptr_symbol}" \
>> +		     "Logical tag \\(0x${ltag_hexnz}\\) does not match the allocation tag \\(0x${atag_hexnz}\\) for address $hex\." \
>> +		     "check mismatch with tag ${i}"
>> +	}
>> +    # Reset the tagged ptr to its original value
>> +    gdb_test_no_output "set variable ${tagged_ptr_symbol} = ${tagged_ptr_addr}" \
>> +		       "reset ${tagged_ptr_symbol} to ${tagged_ptr_addr}"
> 
> The indentation is off here.
> 

Oops. Fixed now.

>> diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
>> index 55154db6a5..347704ce0a 100644
>> --- a/gdb/testsuite/lib/gdb.exp
>> +++ b/gdb/testsuite/lib/gdb.exp
>> @@ -2679,6 +2679,22 @@ proc supports_get_siginfo_type {} {
>>       }
>>   }
>>   
>> +# Return 1 if memory tagging is supported at runtime, otherwise return 0.
>> +
>> +proc supports_memtag {} {
> 
> Should this use gdb_caching_proc?
> 

It should, since we don't expect the setting to change across the run.

> Simon
>