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Use i386 CR0 and CR4 register bits from <kernaux/arch/i386.h>

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This commit is contained in:
Alex Kotov 2021-12-18 08:31:20 +05:00
parent 3e66eb48db
commit afa7c3c50d
Signed by: kotovalexarian
GPG key ID: 553C0EBBEB5D5F08
1 changed files with 6 additions and 25 deletions
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31
kernel/paging.c
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@ -6,25 +6,6 @@
#include <kernaux/libc.h>
#include <kernaux/stdlib.h>
// CR0 bits
#define I386_CR0_PE 0x00000001 // Protected mode
#define I386_CR0_MP 0x00000002 // Monitor Coprocessor
#define I386_CR0_EM 0x00000004 // Emulate
#define I386_CR0_TS 0x00000008 // Task Switched
#define I386_CR0_ET 0x00000010 // Extension Type
#define I386_CR0_WP 0x00010000 // Enable paging
#define I386_CR0_PG 0x80000000 // Enable paging
// some CR4 bits
#define I386_CR4_VME 0x00000001 // Virtual 8086
#define I386_CR4_PVI 0x00000002 // Virtual ints
#define I386_CR4_TSD 0x00000004 // RDTSC privileged
#define I386_CR4_DE 0x00000008 // Debugging extensions
#define I386_CR4_PSE 0x00000010 // Page size extensions
#define I386_CR4_PAE 0x00000020 // Physical addr extens
#define I386_CR4_MCE 0x00000040 // Machine check enable
#define I386_CR4_PGE 0x00000080 // Global page flag enable
static PageDir page_dir;
void paging_enable()
@ -32,26 +13,26 @@ void paging_enable()
unsigned long cr0 = kernaux_arch_i386_read_cr0();
unsigned long cr4 = kernaux_arch_i386_read_cr4();
assert(cr0 & I386_CR0_PE, "The boot loader should have put us in protected mode.");
assert(cr0 & KERNAUX_ARCH_I386_CR0_PE, "The boot loader should have put us in protected mode.");
// First clear PG and PGE flag, as PGE must be enabled after PG.
kernaux_arch_i386_write_cr0(cr0 & ~I386_CR0_PG);
kernaux_arch_i386_write_cr4(cr4 & ~(I386_CR4_PGE | I386_CR4_PSE));
kernaux_arch_i386_write_cr0(cr0 & ~KERNAUX_ARCH_I386_CR0_PG);
kernaux_arch_i386_write_cr4(cr4 & ~(KERNAUX_ARCH_I386_CR4_PGE | KERNAUX_ARCH_I386_CR4_PSE));
cr0 = kernaux_arch_i386_read_cr0();
cr4 = kernaux_arch_i386_read_cr4();
// Our page table contains 4MB entries.
cr4 |= I386_CR4_PSE;
cr4 |= KERNAUX_ARCH_I386_CR4_PSE;
kernaux_arch_i386_write_cr4(cr4);
// First enable paging, then enable global page flag.
cr0 |= I386_CR0_PG;
cr0 |= KERNAUX_ARCH_I386_CR0_PG;
kernaux_arch_i386_write_cr0(cr0);
cr0 |= I386_CR0_WP;
cr0 |= KERNAUX_ARCH_I386_CR0_WP;
kernaux_arch_i386_write_cr0(cr0);
kernaux_arch_i386_write_cr4(cr4);