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/*
* x86_64 specific EFI support functions
* Based on Extensible Firmware Interface Specification version 1.0
*
* Copyright (C) 2005-2008 Intel Co.
* Fenghua Yu <fenghua.yu@intel.com>
* Bibo Mao <bibo.mao@intel.com>
* Chandramouli Narayanan <mouli@linux.intel.com>
* Huang Ying <ying.huang@intel.com>
*
* Code to convert EFI to E820 map has been implemented in elilo bootloader
* based on a EFI patch by Edgar Hucek. Based on the E820 map, the page table
* is setup appropriately for EFI runtime code.
* - mouli 06/14/2007.
*
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/types.h>
#include <linux/spinlock.h>
#include <linux/bootmem.h>
#include <linux/ioport.h>
#include <linux/module.h>
#include <linux/efi.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/reboot.h>
#include <linux/slab.h>
#include <asm/setup.h>
#include <asm/page.h>
#include <asm/e820.h>
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
#include <asm/proto.h>
#include <asm/efi.h>
#include <asm/cacheflush.h>
#include <asm/fixmap.h>
#include <asm/realmode.h>
static pgd_t *save_pgd __initdata;
static unsigned long efi_flags __initdata;
/*
* We allocate runtime services regions bottom-up, starting from -4G, i.e.
* 0xffff_ffff_0000_0000 and limit EFI VA mapping space to 64G.
*/
static u64 efi_va = -4 * (1UL << 30);
#define EFI_VA_END (-68 * (1UL << 30))
/*
* Scratch space used for switching the pagetable in the EFI stub
*/
struct efi_scratch {
u64 r15;
u64 prev_cr3;
pgd_t *efi_pgt;
bool use_pgd;
};
static void __init early_code_mapping_set_exec(int executable)
{
efi_memory_desc_t *md;
void *p;
if (!(__supported_pte_mask & _PAGE_NX))
return;
/* Make EFI service code area executable */
for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
md = p;
if (md->type == EFI_RUNTIME_SERVICES_CODE ||
md->type == EFI_BOOT_SERVICES_CODE)
efi_set_executable(md, executable);
}
}
void __init efi_call_phys_prelog(void)
{
unsigned long vaddress;
int pgd;
int n_pgds;
if (!efi_enabled(EFI_OLD_MEMMAP))
return;
early_code_mapping_set_exec(1);
local_irq_save(efi_flags);
n_pgds = DIV_ROUND_UP((max_pfn << PAGE_SHIFT), PGDIR_SIZE);
save_pgd = kmalloc(n_pgds * sizeof(pgd_t), GFP_KERNEL);
for (pgd = 0; pgd < n_pgds; pgd++) {
save_pgd[pgd] = *pgd_offset_k(pgd * PGDIR_SIZE);
vaddress = (unsigned long)__va(pgd * PGDIR_SIZE);
set_pgd(pgd_offset_k(pgd * PGDIR_SIZE), *pgd_offset_k(vaddress));
}
__flush_tlb_all();
}
void __init efi_call_phys_epilog(void)
{
/*
* After the lock is released, the original page table is restored.
*/
int pgd;
int n_pgds = DIV_ROUND_UP((max_pfn << PAGE_SHIFT) , PGDIR_SIZE);
if (!efi_enabled(EFI_OLD_MEMMAP))
return;
for (pgd = 0; pgd < n_pgds; pgd++)
set_pgd(pgd_offset_k(pgd * PGDIR_SIZE), save_pgd[pgd]);
kfree(save_pgd);
__flush_tlb_all();
local_irq_restore(efi_flags);
early_code_mapping_set_exec(0);
}
/*
* Add low kernel mappings for passing arguments to EFI functions.
*/
void efi_sync_low_kernel_mappings(void)
{
unsigned num_pgds;
pgd_t *pgd = (pgd_t *)__va(real_mode_header->trampoline_pgd);
if (efi_enabled(EFI_OLD_MEMMAP))
return;
num_pgds = pgd_index(MODULES_END - 1) - pgd_index(PAGE_OFFSET);
memcpy(pgd + pgd_index(PAGE_OFFSET),
init_mm.pgd + pgd_index(PAGE_OFFSET),
sizeof(pgd_t) * num_pgds);
}
void efi_setup_page_tables(void)
{
efi_scratch.efi_pgt = (pgd_t *)(unsigned long)real_mode_header->trampoline_pgd;
if (!efi_enabled(EFI_OLD_MEMMAP))
efi_scratch.use_pgd = true;
}
static void __init __map_region(efi_memory_desc_t *md, u64 va)
{
pgd_t *pgd = (pgd_t *)__va(real_mode_header->trampoline_pgd);
unsigned long pf = 0, size;
u64 end;
if (!(md->attribute & EFI_MEMORY_WB))
pf |= _PAGE_PCD;
size = md->num_pages << PAGE_SHIFT;
end = va + size;
if (kernel_map_pages_in_pgd(pgd, md->phys_addr, va, md->num_pages, pf))
pr_warn("Error mapping PA 0x%llx -> VA 0x%llx!\n",
md->phys_addr, va);
}
void __init efi_map_region(efi_memory_desc_t *md)
{
unsigned long size = md->num_pages << PAGE_SHIFT;
u64 pa = md->phys_addr;
if (efi_enabled(EFI_OLD_MEMMAP))
return old_map_region(md);
/*
* Make sure the 1:1 mappings are present as a catch-all for b0rked
* firmware which doesn't update all internal pointers after switching
* to virtual mode and would otherwise crap on us.
*/
__map_region(md, md->phys_addr);
efi_va -= size;
/* Is PA 2M-aligned? */
if (!(pa & (PMD_SIZE - 1))) {
efi_va &= PMD_MASK;
} else {
u64 pa_offset = pa & (PMD_SIZE - 1);
u64 prev_va = efi_va;
/* get us the same offset within this 2M page */
efi_va = (efi_va & PMD_MASK) + pa_offset;
if (efi_va > prev_va)
efi_va -= PMD_SIZE;
}
if (efi_va < EFI_VA_END) {
pr_warn(FW_WARN "VA address range overflow!\n");
return;
}
/* Do the VA map */
__map_region(md, efi_va);
md->virt_addr = efi_va;
}
void __iomem *__init efi_ioremap(unsigned long phys_addr, unsigned long size,
u32 type, u64 attribute)
{
unsigned long last_map_pfn;
if (type == EFI_MEMORY_MAPPED_IO)
return ioremap(phys_addr, size);
last_map_pfn = init_memory_mapping(phys_addr, phys_addr + size);
if ((last_map_pfn << PAGE_SHIFT) < phys_addr + size) {
unsigned long top = last_map_pfn << PAGE_SHIFT;
efi_ioremap(top, size - (top - phys_addr), type, attribute);
}
if (!(attribute & EFI_MEMORY_WB))
efi_memory_uc((u64)(unsigned long)__va(phys_addr), size);
return (void __iomem *)__va(phys_addr);
}
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