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Kernel: Align read operation in HPET registers' block

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Liav A 2020-04-01 15:06:48 +03:00 committed by Andreas Kling
parent 175ec99814
commit b1365d94f4
1 changed files with 3 additions and 6 deletions
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9
Kernel/Time/HPET.cpp
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@ -74,9 +74,7 @@ struct [[gnu::packed]] TimerStructure
struct [[gnu::packed]] HPETCapabilityRegister
{
u8 revision_id;
u8 attributes;
u16 vendor_id;
u32 attributes; // Note: We must do a 32 bit access to offsets 0x0, or 0x4 only, according to HPET spec.
u32 main_counter_tick_period;
u64 reserved;
};
@ -90,7 +88,7 @@ struct [[gnu::packed]] HPETRegister
struct [[gnu::packed]] HPETRegistersBlock
{
union {
volatile HPETCapabilityRegister capabilities; // Note: We must do a 32 bit access to offsets 0x0, or 0x4 only, according to HPET spec.
volatile HPETCapabilityRegister capabilities;
volatile HPETRegister raw_capabilites;
};
HPETRegister configuration;
@ -155,8 +153,7 @@ bool HPET::check_for_exisiting_periodic_timers()
auto block_region = MM.allocate_kernel_region(p_block, (PAGE_SIZE * 2), "HPET Initialization", Region::Access::Read);
auto* registers = (volatile HPETRegistersBlock*)block_region->vaddr().offset(p_block.offset_in_page()).as_ptr();
auto* capabilities_register = (volatile HPETCapabilityRegister*)&registers->capabilities;
size_t timers_count = (capabilities_register->attributes & 0x1f) + 1;
size_t timers_count = ((registers->raw_capabilites.reg >> 8) & 0x1f) + 1;
for (size_t index = 0; index < timers_count; index++) {
if (registers->timers[index].configuration_and_capability & (u32)HPETFlags::TimerConfiguration::PeriodicInterruptCapable)
return true;