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Code Issues Releases Activity

kern: KConditionVariable::SignalImpl

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This commit is contained in:
Michael Scire 2020-07-22 03:29:27 -07:00 committed by SciresM
parent 7aa3120f60
commit 632a75eee7
4 changed files with 80 additions and 1 deletions
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1
libraries/libmesosphere/include/mesosphere/arch/arm64/kern_userspace_memory_access.hpp
View file

@ -39,6 +39,7 @@ namespace ams::kern::arch::arm64 {
static bool ClearMemoryAligned64Bit(void *dst, size_t size);
static bool ClearMemorySize32Bit(void *dst);
static bool UpdateLockAtomic(u32 *out, u32 *address, u32 if_zero, u32 new_orr_mask);
static bool UpdateIfEqualAtomic(s32 *out, s32 *address, s32 compare_value, s32 new_value);
static bool DecrementIfLessThanAtomic(s32 *out, s32 *address, s32 compare);

2
libraries/libmesosphere/include/mesosphere/kern_k_auto_object.hpp
View file

@ -239,6 +239,8 @@ namespace ams::kern {
constexpr ALWAYS_INLINE T *GetPointerUnsafe() { return this->obj; }
constexpr ALWAYS_INLINE T *ReleasePointerUnsafe() { T *ret = this->obj; this->obj = nullptr; return ret; }
constexpr ALWAYS_INLINE bool IsNull() const { return this->obj == nullptr; }
constexpr ALWAYS_INLINE bool IsNotNull() const { return this->obj != nullptr; }
};

28
libraries/libmesosphere/source/arch/arm64/kern_userspace_memory_access_asm.s
View file

@ -428,6 +428,34 @@ _ZN3ams4kern4arch5arm6415UserspaceAccess20ClearMemorySize32BitEPv:
mov x0, #1
ret
/* ams::kern::arch::arm64::UserspaceAccess::UpdateLockAtomic(u32 *out, u32 *address, u32 if_zero, u32 new_orr_mask) */
.section .text._ZN3ams4kern4arch5arm6415UserspaceAccess16UpdateLockAtomicEPjS4_jj, "ax", %progbits
.global _ZN3ams4kern4arch5arm6415UserspaceAccess16UpdateLockAtomicEPjS4_jj
.type _ZN3ams4kern4arch5arm6415UserspaceAccess16UpdateLockAtomicEPjS4_jj, %function
.balign 0x10
_ZN3ams4kern4arch5arm6415UserspaceAccess16UpdateLockAtomicEPjS4_jj:
/* Load the value from the address. */
ldaxr w4, [x1]
/* Orr in the new mask. */
orr w5, w4, w3
/* If the value is zero, use the if_zero value, otherwise use the newly orr'd value. */
cmp w4, wzr
csel w5, w2, w5, eq
/* Try to store. */
stlxr w6, w5, [x1]
/* If we failed to store, try again. */
cbnz w6, _ZN3ams4kern4arch5arm6415UserspaceAccess16UpdateLockAtomicEPjS4_jj
/* We're done. */
str w4, [x0]
mov x0, #1
ret
/* ams::kern::arch::arm64::UserspaceAccess::UpdateIfEqualAtomic(s32 *out, s32 *address, s32 compare_value, s32 new_value) */
.section .text._ZN3ams4kern4arch5arm6415UserspaceAccess19UpdateIfEqualAtomicEPiS4_ii, "ax", %progbits
.global _ZN3ams4kern4arch5arm6415UserspaceAccess19UpdateIfEqualAtomicEPiS4_ii

50
libraries/libmesosphere/source/kern_k_condition_variable.cpp
View file

@ -29,6 +29,10 @@ namespace ams::kern {
return UserspaceAccess::CopyMemoryToUserSize32Bit(GetVoidPointer(address), p);
}
ALWAYS_INLINE bool UpdateLockAtomic(u32 *out, KProcessAddress address, u32 if_zero, u32 new_orr_mask) {
return UserspaceAccess::UpdateLockAtomic(out, GetPointer<u32>(address), if_zero, new_orr_mask);
}
}
Result KConditionVariable::SignalToAddress(KProcessAddress addr) {
@ -117,7 +121,51 @@ namespace ams::kern {
}
KThread *KConditionVariable::SignalImpl(KThread *thread) {
MESOSPHERE_UNIMPLEMENTED();
/* Check pre-conditions. */
MESOSPHERE_ASSERT(KScheduler::IsSchedulerLockedByCurrentThread());
/* Update the tag. */
KProcessAddress address = thread->GetAddressKey();
u32 own_tag = thread->GetAddressKeyValue();
u32 prev_tag;
bool can_access;
{
KScopedInterruptDisable di;
can_access = cpu::CanAccessAtomic(address);
if (AMS_LIKELY(can_access)) {
UpdateLockAtomic(std::addressof(prev_tag), address, own_tag, ams::svc::HandleWaitMask);
}
}
KThread *thread_to_close = nullptr;
if (AMS_LIKELY(can_access)) {
if (prev_tag == ams::svc::InvalidHandle) {
/* If nobody held the lock previously, we're all good. */
thread->SetSyncedObject(nullptr, ResultSuccess());
thread->Wakeup();
} else {
/* Get the previous owner. */
KThread *owner_thread = GetCurrentProcess().GetHandleTable().GetObjectWithoutPseudoHandle<KThread>(static_cast<ams::svc::Handle>(prev_tag & ~ams::svc::HandleWaitMask))
.ReleasePointerUnsafe();
if (AMS_LIKELY(owner_thread != nullptr)) {
/* Add the thread as a waiter on the owner. */
owner_thread->AddWaiter(thread);
thread_to_close = owner_thread;
} else {
/* The lock was tagged with a thread that doesn't exist. */
thread->SetSyncedObject(nullptr, svc::ResultInvalidState());
thread->Wakeup();
}
}
} else {
/* If the address wasn't accessible, note so. */
thread->SetSyncedObject(nullptr, svc::ResultInvalidCurrentMemory());
thread->Wakeup();
}
return thread_to_close;
}
void KConditionVariable::Signal(uintptr_t cv_key, s32 count) {