Aren/haiku
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

kernel/x86: init the tsc frequency and clock speed from CPUID when available

Browse Source 
only for Intel newer CPUs.

Change-Id: Icd83f3b643796bfb3725b5c8877b9e7828bc71d9
Reviewed-on: https://review.haiku-os.org/c/haiku/+/5688
Reviewed-by: Adrien Destugues <pulkomandy@pulkomandy.tk>
Reviewed-by: Fredrik Holmqvist <fredrik.holmqvist@gmail.com>
Reviewed-by: Alex von Gluck IV <kallisti5@unixzen.com>
Tested-by: Commit checker robot <no-reply+buildbot@haiku-os.org>
This commit is contained in:
Jérôme Duval 2022-09-23 11:28:36 +02:00 committed by Alex von Gluck IV
parent 84bd9b4ad5
commit 2e69f2b076
2 changed files with 85 additions and 22 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

95
src/system/kernel/arch/x86/arch_cpu.cpp
View File

@ -1403,12 +1403,85 @@ detect_amdc1e_noarat()
}
static void
init_tsc_with_cpuid(kernel_args* args, uint32* conversionFactor)
{
cpu_ent* cpu = get_cpu_struct();
if (cpu->arch.vendor != VENDOR_INTEL)
return;
uint32 model = (cpu->arch.extended_model << 4) | cpu->arch.model;
cpuid_info cpuid;
get_current_cpuid(&cpuid, 0, 0);
uint32 maxBasicLeaf = cpuid.eax_0.max_eax;
if (maxBasicLeaf < 0x15)
return;
get_current_cpuid(&cpuid, 0x15, 0);
if (cpuid.regs.eax == 0 || cpuid.regs.ebx == 0)
return;
uint32 khz = cpuid.regs.ecx / 1000;
uint32 denominator = cpuid.regs.eax;
uint32 numerator = cpuid.regs.ebx;
if (khz == 0 && model == 0x5f) {
// CPUID 0x16 isn't supported, hardcoding
khz = 25000;
}
if (khz == 0 && maxBasicLeaf >= 0x16) {
// for these CPUs the base frequency is also the tsc frequency
get_current_cpuid(&cpuid, 0x16, 0);
khz = cpuid.regs.eax * 1000 * denominator / numerator;
}
if (khz == 0)
return;
dprintf("CPU: using TSC frequency from CPUID\n");
// compute for microseconds as follows (1000000 << 32) / (tsc freq in Hz),
// or (1000 << 32) / (tsc freq in kHz)
*conversionFactor = (1000ULL << 32) / (khz * numerator / denominator);
// overwrite the bootloader value
args->arch_args.system_time_cv_factor = *conversionFactor;
}
static void
init_tsc(kernel_args* args)
{
// init the TSC -> system_time() conversion factors
// try to find the TSC frequency with CPUID
uint32 conversionFactor = args->arch_args.system_time_cv_factor;
init_tsc_with_cpuid(args, &conversionFactor);
uint64 conversionFactorNsecs = (uint64)conversionFactor * 1000;
#ifdef __x86_64__
// The x86_64 system_time() implementation uses 64-bit multiplication and
// therefore shifting is not necessary for low frequencies (it's also not
// too likely that there'll be any x86_64 CPUs clocked under 1GHz).
__x86_setup_system_time((uint64)conversionFactor << 32,
conversionFactorNsecs);
#else
if (conversionFactorNsecs >> 32 != 0) {
// the TSC frequency is < 1 GHz, which forces us to shift the factor
__x86_setup_system_time(conversionFactor, conversionFactorNsecs >> 16,
true);
} else {
// the TSC frequency is >= 1 GHz
__x86_setup_system_time(conversionFactor, conversionFactorNsecs, false);
}
#endif
}
status_t
arch_cpu_init_percpu(kernel_args* args, int cpu)
{
load_microcode(cpu);
detect_cpu(cpu);
if (cpu == 0)
init_tsc(args);
if (!gCpuIdleFunc) {
if (detect_amdc1e_noarat())
gCpuIdleFunc = amdc1e_noarat_idle;
@ -1446,28 +1519,6 @@ arch_cpu_init(kernel_args* args)
dprintf("CPU: no microcode provided\n");
}
// init the TSC -> system_time() conversion factors
uint32 conversionFactor = args->arch_args.system_time_cv_factor;
uint64 conversionFactorNsecs = (uint64)conversionFactor * 1000;
#ifdef __x86_64__
// The x86_64 system_time() implementation uses 64-bit multiplication and
// therefore shifting is not necessary for low frequencies (it's also not
// too likely that there'll be any x86_64 CPUs clocked under 1GHz).
__x86_setup_system_time((uint64)conversionFactor << 32,
conversionFactorNsecs);
#else
if (conversionFactorNsecs >> 32 != 0) {
// the TSC frequency is < 1 GHz, which forces us to shift the factor
__x86_setup_system_time(conversionFactor, conversionFactorNsecs >> 16,
true);
} else {
// the TSC frequency is >= 1 GHz
__x86_setup_system_time(conversionFactor, conversionFactorNsecs, false);
}
#endif
// Initialize descriptor tables.
x86_descriptors_init(args);

12
src/system/kernel/arch/x86/arch_system_info.cpp
View File

@ -100,6 +100,18 @@ arch_system_info_init(struct kernel_args *args)
| (cpu->arch.family << 8) | (cpu->arch.model << 4) | cpu->arch.stepping;
sCPUClockSpeed = args->arch_args.cpu_clock_speed;
if (cpu->arch.vendor == VENDOR_INTEL) {
cpuid_info cpuid;
get_current_cpuid(&cpuid, 0, 0);
uint32 maxBasicLeaf = cpuid.eax_0.max_eax;
if (maxBasicLeaf >= 0x16) {
get_current_cpuid(&cpuid, 0x16, 0);
if (cpuid.regs.eax != 0) {
sCPUClockSpeed = cpuid.regs.eax * 1000000LL;
dprintf("found clock speed with CPUID.16h\n");
}
}
}
return B_OK;
}