29 lines
651 B
C
29 lines
651 B
C
#include <asm/processor.h>
|
|
|
|
/*
|
|
* __force_order is used by special_insns.h asm code to force instruction
|
|
* serialization.
|
|
*
|
|
* It is not referenced from the code, but GCC < 5 with -fPIE would fail
|
|
* due to an undefined symbol. Define it to make these ancient GCCs work.
|
|
*/
|
|
unsigned long __force_order;
|
|
|
|
int l5_paging_required(void)
|
|
{
|
|
/* Check if leaf 7 is supported. */
|
|
|
|
if (native_cpuid_eax(0) < 7)
|
|
return 0;
|
|
|
|
/* Check if la57 is supported. */
|
|
if (!(native_cpuid_ecx(7) & (1 << (X86_FEATURE_LA57 & 31))))
|
|
return 0;
|
|
|
|
/* Check if 5-level paging has already been enabled. */
|
|
if (native_read_cr4() & X86_CR4_LA57)
|
|
return 0;
|
|
|
|
return 1;
|
|
}
|