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Kernel: Add support for 64-bit unaligned Mem-ops

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Also let the compiler enforce the size and type restrictions
This commit is contained in:
Hendiadyoin1 2021-07-01 14:51:41 +02:00 • committed by Andreas Kling
parent 6b9cf8376e
commit 5f6c513610
1 changed files with 29 additions and 16 deletions
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45
Kernel/Arch/x86/CPU.h
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@ -7,6 +7,7 @@
#pragma once
#include <AK/Atomic.h>
#include <AK/Concepts.h>
#include <AK/Vector.h>
#include <Kernel/Arch/x86/DescriptorTable.h>
@ -29,47 +30,59 @@ inline u32 get_iopl_from_eflags(u32 eflags)
return (eflags & iopl_mask) >> 12;
}
template<typename T>
void read_possibly_unaligned_data(u8* where, T& data)
template<Integral T>
void read_possibly_unaligned_data(u8* where, T& data) requires(sizeof(T) == 8 || sizeof(T) == 4 || sizeof(T) == 2)
{
// FIXME: Implement 64 bit unaligned data access
VERIFY(sizeof(T) == 8 || sizeof(T) == 4 || sizeof(T) == 2);
if (((FlatPtr)where % sizeof(T)) == 0) {
if (((FlatPtr)where % alignof(T)) == 0) {
data = *(T*)where;
return;
}
if (sizeof(T) == 2) {
data = *(u8*)where | ((u16)(*(where + 1)) << 8);
if constexpr (sizeof(T) == 2) {
data = *where | ((u16)(*(where + 1)) << 8);
return;
}
if (sizeof(T) == 4) {
data = *(u8*)where | (((u32) * (where + 1)) << 8) | (((u32) * (where + 2)) << 16) | (((u32) * (u8*)(where + 3)) << 24);
if constexpr (sizeof(T) == 4) {
data = *where | (((u32) * (where + 1)) << 8) | (((u32) * (where + 2)) << 16) | (((u32) * (where + 3)) << 24);
return;
}
if constexpr (sizeof(T) == 8) {
data = *where | (((u32) * (where + 1)) << 8) | (((u64) * (where + 2)) << 16) | (((u64) * (where + 3)) << 24)
| (((u64) * (where + 4)) << 32) | (((u64) * (where + 5)) << 40) | (((u64) * (where + 6)) << 48) | (((u64) * (where + 7)) << 56);
return;
}
VERIFY_NOT_REACHED();
}
template<typename T>
void write_possibly_unaligned_data(u8* where, T data)
template<Integral T>
void write_possibly_unaligned_data(u8* where, T data) requires(sizeof(T) == 8 || sizeof(T) == 4 || sizeof(T) == 2)
{
// FIXME: Implement 64 bit unaligned data access
VERIFY(sizeof(T) == 8 || sizeof(T) == 4 || sizeof(T) == 2);
if (((FlatPtr)where % sizeof(T)) == 0) {
if (((FlatPtr)where % alignof(T)) == 0) {
*(T*)where = data;
return;
}
if (sizeof(T) == 2) {
if constexpr (sizeof(T) == 2) {
where[0] = (u8)(data & 0xFF);
where[1] = (u8)((data >> 8) & 0xFF);
return;
}
if (sizeof(T) == 4) {
if constexpr (sizeof(T) == 4) {
where[0] = (u8)(data & 0xFF);
where[1] = (u8)((data >> 8) & 0xFF);
where[2] = (u8)((data >> 16) & 0xFF);
where[3] = (u8)((data >> 24) & 0xFF);
return;
}
if constexpr (sizeof(T) == 8) {
where[0] = (u8)(data & 0xFF);
where[1] = (u8)((data >> 8) & 0xFF);
where[2] = (u8)((data >> 16) & 0xFF);
where[3] = (u8)((data >> 24) & 0xFF);
where[5] = (u8)(data >> 32 & 0xFF);
where[5] = (u8)((data >> 40) & 0xFF);
where[6] = (u8)((data >> 48) & 0xFF);
where[7] = (u8)((data >> 52) & 0xFF);
return;
}
VERIFY_NOT_REACHED();
}