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Kernel: Detect syscall/sysenter support

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Tom 2020-07-07 19:23:38 -06:00 • committed by Andreas Kling
parent 5b6920a18a
commit ce5ae83963
2 changed files with 25 additions and 2 deletions
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16
Kernel/Arch/i386/CPU.cpp
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@ -788,10 +788,20 @@ void Processor::cpu_detect()
set_feature(CPUFeature::TSC);
if (processor_info.ecx() & (1 << 30))
set_feature(CPUFeature::RDRAND);
if (processor_info.edx() & (1 << 11)) {
u32 stepping = processor_info.eax() & 0xf;
u32 model = (processor_info.eax() >> 4) & 0xf;
u32 family = (processor_info.eax() >> 8) & 0xf;
if (!(family == 6 && model < 3 && stepping < 3))
set_feature(CPUFeature::SEP);
}
CPUID extended_processor_info(0x80000001);
if (extended_processor_info.edx() & (1 << 20))
set_feature(CPUFeature::NX);
if (extended_processor_info.edx() & (1 << 11)) {
// Only available in 64 bit mode
set_feature(CPUFeature::SYSCALL);
}
CPUID extended_features(0x7);
if (extended_features.ebx() & (1 << 20))
@ -895,6 +905,10 @@ String Processor::features_string() const
return "tsc";
case CPUFeature::UMIP:
return "umip";
case CPUFeature::SEP:
return "sep";
case CPUFeature::SYSCALL:
return "syscall";
// no default statement here intentionally so that we get
// a warning if a new feature is forgotten to be added here
}

11
Kernel/Arch/i386/CPU.h
View file

@ -599,7 +599,9 @@ enum class CPUFeature : u32 {
SMEP = (1 << 6),
SSE = (1 << 7),
TSC = (1 << 8),
UMIP = (1 << 9)
UMIP = (1 << 9),
SEP = (1 << 10),
SYSCALL = (1 << 11)
};
class Thread;
@ -613,6 +615,13 @@ struct TrapFrame;
#define GDT_SELECTOR_PROC 0x30
#define GDT_SELECTOR_TSS 0x38
// SYSENTER makes certain assumptions on how the GDT is structured:
static_assert(GDT_SELECTOR_CODE0 + 8 == GDT_SELECTOR_DATA0); // SS0 = CS0 + 8
// SYSEXIT makes certain assumptions on how the GDT is structured:
static_assert(GDT_SELECTOR_CODE0 + 16 == GDT_SELECTOR_CODE3); // CS3 = CS0 + 16
static_assert(GDT_SELECTOR_CODE0 + 24 == GDT_SELECTOR_DATA3); // SS3 = CS0 + 32
class ProcessorInfo;
struct MemoryManagerData;
struct ProcessorMessageEntry;