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NFC: CapPtr in external_pointer; drop capptr_rebound

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capptr_rebound was only ever going to be used for external_pointer, which now
operates entirely using pointer_offset.  So instead, just make external_pointer
use capptr::AllocWild<void>, capptr_from_client, and a new capptr_reveal_wild.
This commit is contained in:
Nathaniel Wesley Filardo
2021-10-19 13:33:10 +01:00
committed by Nathaniel Wesley Filardo
parent 3462c53983
commit c54d2b527d
4 changed files with 23 additions and 32 deletions
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24
src/mem/localalloc.h
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@@ -628,26 +628,28 @@ namespace snmalloc
// be implicit domestication through the `SharedStateHandle::Pagemap` or
// we could just leave well enough alone.
// TODO bring back the CHERI bits. Wes to review if required.
capptr::AllocWild<void> p = capptr_from_client(p_raw);
MetaEntry entry =
SharedStateHandle::Pagemap::template get_metaentry<true>(
core_alloc->backend_state_ptr(), address_cast(p_raw));
core_alloc->backend_state_ptr(), address_cast(p));
auto sizeclass = entry.get_sizeclass();
if (likely(entry.get_remote() != SharedStateHandle::fake_large_remote))
{
auto rsize = sizeclass_to_size(sizeclass);
auto offset =
address_cast(p_raw) & (sizeclass_to_slab_size(sizeclass) - 1);
auto offset = address_cast(p) & (sizeclass_to_slab_size(sizeclass) - 1);
auto start_offset = round_by_sizeclass(sizeclass, offset);
if constexpr (location == Start)
{
UNUSED(rsize);
return pointer_offset(p_raw, start_offset - offset);
return capptr_reveal_wild(pointer_offset(p, start_offset - offset));
}
else if constexpr (location == End)
return pointer_offset(p_raw, rsize + start_offset - offset - 1);
return capptr_reveal_wild(
pointer_offset(p, rsize + start_offset - offset - 1));
else
return pointer_offset(p_raw, rsize + start_offset - offset);
return capptr_reveal_wild(
pointer_offset(p, rsize + start_offset - offset));
}
// Sizeclass zero of a large allocation is used for not managed by us.
@@ -655,13 +657,13 @@ namespace snmalloc
{
// This is a large allocation, find start by masking.
auto rsize = bits::one_at_bit(sizeclass);
auto start = pointer_align_down(p_raw, rsize);
auto start = pointer_align_down(p, rsize);
if constexpr (location == Start)
return start;
return capptr_reveal_wild(start);
else if constexpr (location == End)
return pointer_offset(start, rsize - 1);
return capptr_reveal_wild(pointer_offset(start, rsize - 1));
else
return pointer_offset(start, rsize);
return capptr_reveal_wild(pointer_offset(start, rsize));
}
#else
UNUSED(p_raw);