diff options
Diffstat (limited to 'sys/arch/amd64/amd64/machdep.c')
| -rw-r--r-- | sys/arch/amd64/amd64/machdep.c | 26 |
1 files changed, 24 insertions, 2 deletions
diff --git a/sys/arch/amd64/amd64/machdep.c b/sys/arch/amd64/amd64/machdep.c index 8761fbe..7720620 100644 --- a/sys/arch/amd64/amd64/machdep.c +++ b/sys/arch/amd64/amd64/machdep.c @@ -300,18 +300,20 @@ cpu_get_vendor(struct cpu_info *ci) static void cpu_get_info(struct cpu_info *ci) { - uint32_t eax, ebx, unused; + uint32_t eax, ebx, ecx, unused; uint8_t ext_model, ext_family; /* Get the vendor information */ cpu_get_vendor(ci); /* Extended features */ - CPUID(0x07, unused, ebx, unused, unused); + CPUID(0x07, unused, ebx, ecx, unused); if (ISSET(ebx, BIT(7))) ci->feat |= CPU_FEAT_SMEP; if (ISSET(ebx, BIT(20))) ci->feat |= CPU_FEAT_SMAP; + if (ISSET(ecx, BIT(2))) + ci->feat |= CPU_FEAT_UMIP; /* * Processor info and feature bits @@ -341,6 +343,25 @@ cpu_get_info(struct cpu_info *ci) } } +/* + * The CR4.UMIP bit prevents user programs from + * executing instructions related to accessing + * system memory structures. This should be enabled + * by default if supported. + */ +static void +cpu_enable_umip(void) +{ + struct cpu_info *ci = this_cpu(); + uint64_t cr4; + + if (ISSET(ci->feat, CPU_FEAT_UMIP)) { + cr4 = amd64_read_cr4(); + cr4 |= CR4_UMIP; + amd64_write_cr4(cr4); + } +} + void cpu_shootdown_tlb(vaddr_t va) { @@ -572,6 +593,7 @@ cpu_startup(struct cpu_info *ci) cpu_get_info(ci); cpu_enable_smep(); + cpu_enable_umip(); enable_simd(); lapic_init(); |