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Kernel: Don't remap IOAPIC registers every time we try to read/write

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Remapping these registers every time we try to read from or write to
them causes a lot of SMP broadcasts and a lot of other overhead.
This improves boot time noticeably.
This commit is contained in:
Tom 2020-10-26 19:44:10 -06:00 • committed by Andreas Kling
parent c1bfb8cb0e
commit 7a4fb5deef
2 changed files with 9 additions and 9 deletions
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16
Kernel/Interrupts/IOAPIC.cpp
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@ -32,7 +32,6 @@
#include <Kernel/Interrupts/IOAPIC.h>
#include <Kernel/Interrupts/InterruptManagement.h>
#include <Kernel/VM/MemoryManager.h>
#include <Kernel/VM/TypedMapping.h>
//#define IOAPIC_DEBUG
@ -49,6 +48,7 @@ enum DeliveryMode {
IOAPIC::IOAPIC(PhysicalAddress address, u32 gsi_base)
: m_address(address)
, m_regs(map_typed_writable<ioapic_mmio_regs>(m_address))
, m_gsi_base(gsi_base)
, m_id((read_register(0x0) >> 24) & 0xFF)
, m_version(read_register(0x1) & 0xFF)
@ -317,21 +317,19 @@ u16 IOAPIC::get_irr() const
void IOAPIC::write_register(u32 index, u32 value) const
{
InterruptDisabler disabler;
auto regs = map_typed_writable<ioapic_mmio_regs>(m_address);
regs->select = index;
regs->window = value;
m_regs->select = index;
m_regs->window = value;
#ifdef IOAPIC_DEBUG
dbg() << "IOAPIC Writing, Value 0x" << String::format("%x", regs->window) << " @ offset 0x" << String::format("%x", regs->select);
dbg() << "IOAPIC Writing, Value 0x" << String::format("%x", m_regs->window) << " @ offset 0x" << String::format("%x", m_regs->select);
#endif
}
u32 IOAPIC::read_register(u32 index) const
{
InterruptDisabler disabler;
auto regs = map_typed_writable<ioapic_mmio_regs>(m_address);
regs->select = index;
m_regs->select = index;
#ifdef IOAPIC_DEBUG
dbg() << "IOAPIC Reading, Value 0x" << String::format("%x", regs->window) << " @ offset 0x" << String::format("%x", regs->select);
dbg() << "IOAPIC Reading, Value 0x" << String::format("%x", m_regs->window) << " @ offset 0x" << String::format("%x", m_regs->select);
#endif
return regs->window;
return m_regs->window;
}
}