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Kernel: Don't use MMX memcpy() in the kernel.

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I just discovered the hard way that clobbering FPU/MMX/SSE registers in the
kernel makes things very confusing for userspace (and other kernel threads.)

Let's banish all of those things from the kernel to keep things simple.
This commit is contained in:
Andreas Kling 2019-04-22 17:13:18 +02:00
parent 1d02c7b6f1
commit 6693cfb26a
3 changed files with 9 additions and 2 deletions
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4
AK/StdLibExtras.h
View file

@ -11,14 +11,18 @@
#include <AK/Types.h>
#ifndef KERNEL
extern "C" void* mmx_memcpy(void* to, const void* from, size_t);
#endif
[[gnu::always_inline]] inline void fast_dword_copy(dword* dest, const dword* src, size_t count)
{
#ifndef KERNEL
if (count >= 256) {
mmx_memcpy(dest, src, count * sizeof(count));
return;
}
#endif
asm volatile(
"rep movsl\n"
: "=S"(src), "=D"(dest), "=c"(count)