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Turn on EFER NXE bit to allow no-execute pages

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This commit is contained in:
Josh Holtrop 2022-10-27 23:42:18 -04:00
parent 7b531e36ea
commit 1e1c389caf
2 changed files with 20 additions and 0 deletions
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18
src/hulk/cpu.d
View File

@ -5,7 +5,20 @@ module hulk.cpu;
import ldc.llvmasm;
/** MSR register numbers. @{ */
enum uint MSR_EFER = 0xC000_0080u;
/** @} */
/** EFER flags. @{ */
enum uint EFER_SCE = 0x1u;
enum uint EFER_LME = 0x100u;
enum uint EFER_LMA = 0x400u;
enum uint EFER_NXE = 0x800u;
enum uint EFER_SVME = 0x1000u;
enum uint EFER_LMSLE = 0x2000u;
enum uint EFER_FFXSR = 0x4000u;
enum uint EFER_TCE = 0x8000u;
/** @} */
void cli()
{
@ -55,6 +68,11 @@ ulong rdmsr(uint msr)
or %rdx, %rax`, "={rax},{ecx},~{rdx}", msr);
}
void wrmsr(uint msr, ulong value)
{
__asm(`wrmsr`, "{ecx},{edx},{eax}", msr, value >> 32u, value);
}
ubyte in8(ushort ioaddr)
{
return __asm!ubyte("inb %dx, %al", "={al},{dx}", ioaddr);

2
src/hulk/hurl.d
View File

@ -33,6 +33,8 @@ struct hurl
*/
public static void initialize(HulkHeader * header)
{
/* Turn on NXE (no execute enable) flag in the EFER MSR. */
wrmsr(MSR_EFER, rdmsr(MSR_EFER) | EFER_NXE);
m_pt_base = allocate_pt();
size_t hulk_bin_phys_size = cast(ulong)header.total_size - LinkerAddresses.hulk_bss_size;
/* Identity map all physical RAM. */