mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-15 00:04:15 +08:00
ad757b6aa5
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
101 lines
2.8 KiB
C
101 lines
2.8 KiB
C
/*
|
|
* arch/i386/mm/boot_ioremap.c
|
|
*
|
|
* Re-map functions for early boot-time before paging_init() when the
|
|
* boot-time pagetables are still in use
|
|
*
|
|
* Written by Dave Hansen <haveblue@us.ibm.com>
|
|
*/
|
|
|
|
|
|
/*
|
|
* We need to use the 2-level pagetable functions, but CONFIG_X86_PAE
|
|
* keeps that from happenning. If anyone has a better way, I'm listening.
|
|
*
|
|
* boot_pte_t is defined only if this all works correctly
|
|
*/
|
|
|
|
#undef CONFIG_X86_PAE
|
|
#undef CONFIG_PARAVIRT
|
|
#include <asm/page.h>
|
|
#include <asm/pgtable.h>
|
|
#include <asm/tlbflush.h>
|
|
#include <linux/init.h>
|
|
#include <linux/stddef.h>
|
|
|
|
/*
|
|
* I'm cheating here. It is known that the two boot PTE pages are
|
|
* allocated next to each other. I'm pretending that they're just
|
|
* one big array.
|
|
*/
|
|
|
|
#define BOOT_PTE_PTRS (PTRS_PER_PTE*2)
|
|
|
|
static unsigned long boot_pte_index(unsigned long vaddr)
|
|
{
|
|
return __pa(vaddr) >> PAGE_SHIFT;
|
|
}
|
|
|
|
static inline boot_pte_t* boot_vaddr_to_pte(void *address)
|
|
{
|
|
boot_pte_t* boot_pg = (boot_pte_t*)pg0;
|
|
return &boot_pg[boot_pte_index((unsigned long)address)];
|
|
}
|
|
|
|
/*
|
|
* This is only for a caller who is clever enough to page-align
|
|
* phys_addr and virtual_source, and who also has a preference
|
|
* about which virtual address from which to steal ptes
|
|
*/
|
|
static void __boot_ioremap(unsigned long phys_addr, unsigned long nrpages,
|
|
void* virtual_source)
|
|
{
|
|
boot_pte_t* pte;
|
|
int i;
|
|
char *vaddr = virtual_source;
|
|
|
|
pte = boot_vaddr_to_pte(virtual_source);
|
|
for (i=0; i < nrpages; i++, phys_addr += PAGE_SIZE, pte++) {
|
|
set_pte(pte, pfn_pte(phys_addr>>PAGE_SHIFT, PAGE_KERNEL));
|
|
__flush_tlb_one(&vaddr[i*PAGE_SIZE]);
|
|
}
|
|
}
|
|
|
|
/* the virtual space we're going to remap comes from this array */
|
|
#define BOOT_IOREMAP_PAGES 4
|
|
#define BOOT_IOREMAP_SIZE (BOOT_IOREMAP_PAGES*PAGE_SIZE)
|
|
static __initdata char boot_ioremap_space[BOOT_IOREMAP_SIZE]
|
|
__attribute__ ((aligned (PAGE_SIZE)));
|
|
|
|
/*
|
|
* This only applies to things which need to ioremap before paging_init()
|
|
* bt_ioremap() and plain ioremap() are both useless at this point.
|
|
*
|
|
* When used, we're still using the boot-time pagetables, which only
|
|
* have 2 PTE pages mapping the first 8MB
|
|
*
|
|
* There is no unmap. The boot-time PTE pages aren't used after boot.
|
|
* If you really want the space back, just remap it yourself.
|
|
* boot_ioremap(&ioremap_space-PAGE_OFFSET, BOOT_IOREMAP_SIZE)
|
|
*/
|
|
__init void* boot_ioremap(unsigned long phys_addr, unsigned long size)
|
|
{
|
|
unsigned long last_addr, offset;
|
|
unsigned int nrpages;
|
|
|
|
last_addr = phys_addr + size - 1;
|
|
|
|
/* page align the requested address */
|
|
offset = phys_addr & ~PAGE_MASK;
|
|
phys_addr &= PAGE_MASK;
|
|
size = PAGE_ALIGN(last_addr) - phys_addr;
|
|
|
|
nrpages = size >> PAGE_SHIFT;
|
|
if (nrpages > BOOT_IOREMAP_PAGES)
|
|
return NULL;
|
|
|
|
__boot_ioremap(phys_addr, nrpages, boot_ioremap_space);
|
|
|
|
return &boot_ioremap_space[offset];
|
|
}
|