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#include "msr.h"
#include "gdt.h"
void
msr_read(uint32_t msr, uint32_t *lo, uint32_t *hi)
{
__asm__ volatile("rdmsr": "=a"(*lo), "=d"(*hi): "c"(msr));
}
void
msr_write(uint32_t msr, uint32_t lo, uint32_t hi)
{
__asm__ volatile("wrmsr":: "a"(lo), "c"(msr), "d"(hi));
}
void
msr_set_gs_base(uintptr_t gs)
{
union msr_gs_base gs_base = { .gs = gs };
msr_write(MSR_GS_BASE, gs_base.v[0], gs_base.v[1]);
}
uintptr_t
msr_get_gs_base(void)
{
union msr_gs_base gs_base;
msr_read(MSR_GS_BASE, &gs_base.v[0], &gs_base.v[1]);
return gs_base.gs;
}
void
msr_enable_sce(void)
{
uint32_t efer[2];
msr_read(MSR_EFER, &efer[0], &efer[1]);
efer[0] |= MSR_EFER_SCE;
msr_write(MSR_EFER, efer[0], efer[1]);
union msr_star star;
star.kcs = GDT_OFFSET(GDT_KERNEL_CODE);
star.ucs = GDT_OFFSET(GDT_USER_CODE);
msr_write(MSR_STAR, star.v[0], star.v[1]);
}
void
msr_enable_sse(void)
{
uint64_t cr4 = 0;
__asm__ volatile("mov %%cr4, %0": "=r"(cr4));
cr4 &= 0xFFFFFFFFFFFFFFFB;
cr4 |= 0x2;
__asm__ volatile("mov %0, %%cr4":: "r"(cr4));
__asm__ volatile("mov %%cr4, %0": "=r"(cr4));
cr4 |= (3 << 9);
__asm__ volatile("mov %0, %%cr4":: "r"(cr4));
}
void
msr_set_lstar(void *lstar_value)
{
union msr_lstar lstar;
lstar.rip = lstar_value;
msr_write(MSR_LSTAR, lstar.v[0], lstar.v[1]);
}
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