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kern: fix slab heap atomics

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This commit is contained in:
Michael Scire 2020-07-29 02:29:46 -07:00 committed by SciresM
parent 2db6760461
commit b6cb561c47
2 changed files with 88 additions and 15 deletions
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69
libraries/libmesosphere/include/mesosphere/arch/arm64/kern_k_slab_heap_impl.hpp Normal file
View file

@ -0,0 +1,69 @@
/*
* Copyright (c) 2018-2020 Atmosphère-NX
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#pragma once
#include <vapours.hpp>
#include <mesosphere/kern_select_cpu.hpp>
namespace ams::kern::arch::arm64 {
template<typename T>
concept SlabHeapNode = requires (T &t) {
{ t.next } -> std::convertible_to<T *>;
};
template<typename T> requires SlabHeapNode<T>
ALWAYS_INLINE T *AllocateFromSlabAtomic(T **head) {
u32 tmp;
T *node, *next;
__asm__ __volatile__(
"1:\n"
" ldaxr %[node], [%[head]]\n"
" cbz %[node], 2f\n"
" ldr %[next], [%[node]]\n"
" stlxr %w[tmp], %[next], [%[head]]\n"
" cbnz %w[tmp], 1b\n"
" b 3f\n"
"2:\n"
" clrex\n"
"3:\n"
: [tmp]"=&r"(tmp), [node]"=&r"(node), [next]"=&r"(next), [head]"+&r"(head)
:
: "cc", "memory"
);
return node;
}
template<typename T> requires SlabHeapNode<T>
ALWAYS_INLINE void FreeToSlabAtomic(T **head, T *node) {
u32 tmp;
T *next;
__asm__ __volatile__(
"1:\n"
" ldaxr %[next], [%[head]]\n"
" str %[next], [%[node]]\n"
" stlxr %w[tmp], %[node], [%[head]]\n"
" cbnz %w[tmp], 1b\n"
"2:\n"
: [tmp]"=&r"(tmp), [node]"+&r"(node), [next]"=&r"(next), [head]"+&r"(head)
:
: "cc", "memory"
);
}
}

34
libraries/libmesosphere/include/mesosphere/kern_k_slab_heap.hpp
View file

@ -17,6 +17,21 @@
#include <mesosphere/kern_common.hpp>
#include <mesosphere/kern_k_typed_address.hpp>
#if defined(ATMOSPHERE_ARCH_ARM64)
#include <mesosphere/arch/arm64/kern_k_slab_heap_impl.hpp>
namespace ams::kern {
using ams::kern::arch::arm64::AllocateFromSlabAtomic;
using ams::kern::arch::arm64::FreeToSlabAtomic;
}
#else
#error "Unknown architecture for KSlabHeapImpl"
#endif
namespace ams::kern {
namespace impl {
@ -29,8 +44,8 @@ namespace ams::kern {
Node *next;
};
private:
std::atomic<Node *> head;
size_t obj_size;
Node * head;
size_t obj_size;
public:
constexpr KSlabHeapImpl() : head(nullptr), obj_size(0) { MESOSPHERE_ASSERT_THIS(); }
@ -50,15 +65,7 @@ namespace ams::kern {
void *Allocate() {
MESOSPHERE_ASSERT_THIS();
Node *ret = this->head.load();
do {
if (AMS_UNLIKELY(ret == nullptr)) {
break;
}
} while (!this->head.compare_exchange_weak(ret, ret->next));
return ret;
return AllocateFromSlabAtomic(std::addressof(this->head));
}
void Free(void *obj) {
@ -66,10 +73,7 @@ namespace ams::kern {
Node *node = reinterpret_cast<Node *>(obj);
Node *cur_head = this->head.load();
do {
node->next = cur_head;
} while (!this->head.compare_exchange_weak(cur_head, node));
return FreeToSlabAtomic(std::addressof(this->head), node);
}
};