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Kernel: Add RTC as fallback entropy source if HPET is not found

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Maciej Zygmanowski 2021-01-24 12:25:03 +01:00 • committed by Andreas Kling
parent 0a61924727
commit 645657865d
2 changed files with 14 additions and 2 deletions
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14
Kernel/Random.cpp
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@ -30,6 +30,7 @@
#include <Kernel/Devices/RandomDevice.h> #include <Kernel/Devices/RandomDevice.h>
#include <Kernel/Random.h> #include <Kernel/Random.h>
#include <Kernel/Time/HPET.h> #include <Kernel/Time/HPET.h>
#include <Kernel/Time/RTC.h>
#include <Kernel/Time/TimeManagement.h> #include <Kernel/Time/TimeManagement.h>
namespace Kernel { namespace Kernel {
@ -65,14 +66,23 @@ KernelRng::KernelRng()
this->resource().add_random_event(value, i % 32); this->resource().add_random_event(value, i % 32);
} }
} else { } else if (TimeManagement::the().can_query_precise_time()) {
// Add HPET as entropy source if we don't have anything better. // Add HPET as entropy source if we don't have anything better.
klog() << "KernelRng: Using HPET as entropy source (bad!)"; klog() << "KernelRng: Using HPET as entropy source";
for (size_t i = 0; i < resource().pool_count * resource().reseed_threshold; ++i) { for (size_t i = 0; i < resource().pool_count * resource().reseed_threshold; ++i) {
u64 hpet_time = HPET::the().read_main_counter(); u64 hpet_time = HPET::the().read_main_counter();
this->resource().add_random_event(hpet_time, i % 32); this->resource().add_random_event(hpet_time, i % 32);
} }
} else {
// Fallback to RTC
klog() << "KernelRng: Using RTC as entropy source (bad!)";
time_t current_time = RTC::now();
for (size_t i = 0; i < resource().pool_count * resource().reseed_threshold; ++i) {
this->resource().add_random_event(current_time, i % 32);
current_time *= 0x574a;
current_time += 0x40b2;
}
} }
} }

2
Kernel/Time/TimeManagement.h
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@ -80,6 +80,8 @@ public:
timespec remaining_epoch_time_adjustment() const { return m_remaining_epoch_time_adjustment; } timespec remaining_epoch_time_adjustment() const { return m_remaining_epoch_time_adjustment; }
void set_remaining_epoch_time_adjustment(const timespec& adjustment) { m_remaining_epoch_time_adjustment = adjustment; } void set_remaining_epoch_time_adjustment(const timespec& adjustment) { m_remaining_epoch_time_adjustment = adjustment; }
bool can_query_precise_time() const { return m_can_query_precise_time; }
private: private:
bool probe_and_set_legacy_hardware_timers(); bool probe_and_set_legacy_hardware_timers();
bool probe_and_set_non_legacy_hardware_timers(); bool probe_and_set_non_legacy_hardware_timers();