Displaying 4 results from an estimated 4 matches for "tagged_rel".
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2020 Sep 18
2
[MTE] Globals Tagging - Discussion
...So if we just did a RELATIVE relocation then array_end's value would
> have a tag of 2, so you couldn't do:
> for (int* ptr=array; ptr != array_end; ++ptr)
> Since it's always != due to the tags.
> Do I have that right?
Yep - you've got it right, this is why we need TAGGED_RELATIVE. For
clarity, here's the memory layout where array_end is relocated using
TAGGED_RELATIVE{*r_offset = &array[16], r_addend = &array[0]}:
array array_end (padding)
Memory Tag 0x1 0x1 0x2 0x2
Value 0 0 0 0 (0x1 << 56) | &array[16] 0 0
So the address tag of `array` and `arra...
2020 Sep 21
2
[MTE] Globals Tagging - Discussion
...#39;s value would
>>> have a tag of 2, so you couldn't do:
>>> for (int* ptr=array; ptr != array_end; ++ptr)
>>> Since it's always != due to the tags.
>>> Do I have that right?
>>
>>
>> Yep - you've got it right, this is why we need TAGGED_RELATIVE. For clarity, here's the memory layout where array_end is relocated using TAGGED_RELATIVE{*r_offset = &array[16], r_addend = &array[0]}:
>> arrayarray_end(padding)
>> Memory Tag0x10x10x20x2
>> Value0000(0x1 << 56) | &array[16]00
>>
>> So the...
2020 Sep 17
4
[MTE] Globals Tagging - Discussion
...memory tag of the symbol into the
relocated value. For example, the ABS64 relocation becomes:
sym_addr = get_symbol_address() // sym_addr = 0x1008
sym_addr |= get_tag(sym_addr & 0xf) // get_tag(0x1008 & 0xf == 0x1000)
*r_offset = sym_addr + r_addend;
2.
Introduce a TAGGED_RELATIVE relocation - in order to solve the problem
where the tag derivation shouldn't be from the relocation result, e.g.
static int array[16] = {};
// array_end must have the same tag as array[]. array_end is out of
// bounds w.r.t. array, and may point to a completely different globa...
2020 Oct 09
3
[MTE] Globals Tagging - Discussion
...le, the ABS64 relocation becomes:
> > sym_addr = get_symbol_address() // sym_addr = 0x1008
> > sym_addr |= get_tag(sym_addr & 0xf) // get_tag(0x1008 & 0xf ==
> 0x1000)
> > *r_offset = sym_addr + r_addend;
> > 2.
> >
> > Introduce a TAGGED_RELATIVE relocation - in order to solve the problem
> > where the tag derivation shouldn't be from the relocation result, e.g.
> > static int array[16] = {};
> > // array_end must have the same tag as array[]. array_end is out of
> > // bounds w.r.t. array, and m...