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Kernel: Add getter and setter for the X86 CR3 register

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This gets rid of a bunch of inline assembly.
This commit is contained in:
Andreas Kling 2020-02-10 20:00:32 +01:00
parent 7323d085dd
commit 27f0102bbe
3 changed files with 25 additions and 31 deletions
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23
Kernel/Arch/i386/CPU.cpp
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@ -178,9 +178,7 @@ static void dump(const RegisterDump& regs)
u32 cr2;
asm("movl %%cr2, %%eax"
: "=a"(cr2));
u32 cr3;
asm("movl %%cr3, %%eax"
: "=a"(cr3));
u32 cr3 = read_cr3();
u32 cr4;
asm("movl %%cr4, %%eax"
: "=a"(cr4));
@ -271,11 +269,8 @@ void page_fault_handler(RegisterDump regs)
asm("movl %%cr2, %%eax"
: "=a"(fault_address));
u32 fault_page_directory;
asm("movl %%cr3, %%eax"
: "=a"(fault_page_directory));
#ifdef PAGE_FAULT_DEBUG
u32 fault_page_directory = read_cr3();
dbgprintf("%s(%u): ring%u %s page fault in PD=%x, %s%s V%08x\n",
current ? current->process().name().characters() : "(none)",
current ? current->pid() : 0,
@ -716,3 +711,17 @@ void cpu_setup()
kprintf("x86: No RDRAND support detected. Randomness will be shitty\n");
}
}
u32 read_cr3()
{
u32 cr3;
asm("movl %%cr3, %%eax"
: "=a"(cr3));
return cr3;
}
void write_cr3(u32 cr3)
{
asm volatile("movl %%eax, %%cr3" ::"a"(cr3)
: "memory");
}

12
Kernel/Arch/i386/CPU.h
View file

@ -278,15 +278,6 @@ void handle_crash(RegisterDump&, const char* description, int signal);
: "memory")
#define memory_barrier() asm volatile("" :: \
: "memory")
inline u32 cpu_cr3()
{
u32 cr3;
asm volatile("movl %%cr3, %%eax"
: "=a"(cr3));
return cr3;
}
inline u32 cpu_flags()
{
u32 flags;
@ -473,6 +464,9 @@ inline uintptr_t offset_in_page(const void* address)
return offset_in_page((uintptr_t)address);
}
u32 read_cr3();
void write_cr3(u32);
class CPUID {
public:
CPUID(u32 function) { asm volatile("cpuid"