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/* vmem.c - MemTest-86
*
* Virtual memory handling (PAE)
*
* Released under version 2 of the Gnu Public License.
* By Chris Brady
*/
#include "stdint.h"
#include "test.h"
#include "cpuid.h"
extern struct cpu_ident cpu_id;
static unsigned long mapped_win = 1;
void paging_off(void)
{
if (!cpu_id.fid.bits.pae)
return;
__asm__ __volatile__
(
/* Disable paging */
"movl %%cr0, %%eax\n\t"
"andl $0x7FFFFFFF, %%eax\n\t"
"movl %%eax, %%cr0\n\t"
: :
: "ax"
);
}
static void paging_on(void *pdp)
{
if (!cpu_id.fid.bits.pae)
return;
__asm__ __volatile__
(
/* Load the page table address */
"movl %0, %%cr3\n\t"
/* Enable paging */
"movl %%cr0, %%eax\n\t"
"orl $0x80000000, %%eax\n\t"
"movl %%eax, %%cr0\n\t"
:
: "r" (pdp)
: "ax"
);
}
static void paging_on_lm(void *pml)
{
if (!cpu_id.fid.bits.pae)
return;
__asm__ __volatile__
(
/* Load the page table address */
"movl %0, %%cr3\n\t"
/* Enable paging */
"movl %%cr0, %%eax\n\t"
"orl $0x80000000, %%eax\n\t"
"movl %%eax, %%cr0\n\t"
:
: "r" (pml)
: "ax"
);
}
int map_page(unsigned long page)
{
unsigned long i;
struct pde {
unsigned long addr_lo;
unsigned long addr_hi;
};
extern unsigned char pdp[];
extern unsigned char pml4[];
extern struct pde pd2[];
unsigned long win = page >> 19;
/* Less than 2 GB so no mapping is required */
if (win == 0) {
return 0;
}
if (cpu_id.fid.bits.pae == 0) {
/* Fail, we don't have PAE */
return -1;
}
if (cpu_id.fid.bits.lm == 0 && (page > 0x1000000)) {
/* Fail, we want an address that is out of bounds (> 64GB)
* for PAE and no long mode (ie. 32 bit CPU).
*/
return -1;
}
/* Compute the page table entries... */
for(i = 0; i < 1024; i++) {
/*-----------------10/30/2004 12:37PM---------------
* 0xE3 --
* Bit 0 = Present bit. 1 = PDE is present
* Bit 1 = Read/Write. 1 = memory is writable
* Bit 2 = Supervisor/User. 0 = Supervisor only (CPL 0-2)
* Bit 3 = Writethrough. 0 = writeback cache policy
* Bit 4 = Cache Disable. 0 = page level cache enabled
* Bit 5 = Accessed. 1 = memory has been accessed.
* Bit 6 = Dirty. 1 = memory has been written to.
* Bit 7 = Page Size. 1 = page size is 2 MBytes
* --------------------------------------------------*/
pd2[i].addr_lo = ((win & 1) << 31) + ((i & 0x3ff) << 21) + 0xE3;
pd2[i].addr_hi = (win >> 1);
}
paging_off();
if (cpu_id.fid.bits.lm == 1) {
paging_on_lm(pml4);
} else {
paging_on(pdp);
}
mapped_win = win;
return 0;
}
void *mapping(unsigned long phys_page)
{
void *result;
if (phys_page < WIN_SZ_PAGES) {
/* If the page is below 2GB, address it directly */
result = (void *)(phys_page << 12);
}
else {
// Higher physical pages map to a virtual address
// in the 2G-4G range.
unsigned long alias;
alias = phys_page & 0x7FFFF;
alias += 0x80000;
result = (void *)(alias << 12);
}
return result;
}
void *emapping(unsigned long phys_page)
{
void *result;
result = mapping(phys_page - 1);
/* Fill in the low address bits */
result = ((unsigned char *)result) + 0xffc;
return result;
}
unsigned long page_of(void *addr)
{
unsigned long page;
page = ((unsigned long)addr) >> 12;
if (page >= 0x80000) {
page &= 0x7FFFF;
page += mapped_win << 19;
}
#if 0
cprint(LINE_SCROLL -2, 0, "page_of( )-> ");
hprint(LINE_SCROLL -2, 8, ((unsigned long)addr));
hprint(LINE_SCROLL -2, 20, page);
#endif
return page;
}
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