Commit 4de0d4a6 authored by Huang, Ying's avatar Huang, Ying Committed by Ingo Molnar
Browse files

x86: EFI runtime code mapping enhancement 



This patch enhances EFI runtime code memory mapping as following:

- Move __supported_pte_mask & _PAGE_NX checking before invoking
  runtime_code_page_mkexec(). This makes it possible for compiler to
  eliminate runtime_code_page_mkexec() on machine without NX support.

- Use set_memory_x/nx in early_mapping_set_exec(). This eliminates the
  duplicated implementation.

This patch has been tested on Intel x86_64 platform with EFI64/32
firmware.

Signed-off-by: default avatarHuang Ying <ying.huang@intel.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent e85f2051

arch/x86/kernel/efi.c

+2 −4
Original line number Diff line number Diff line
@@ -384,9 +384,6 @@ static void __init runtime_code_page_mkexec(void) 
	efi_memory_desc_t *md;

	void *p;



	if (!(__supported_pte_mask & _PAGE_NX))

		return;



	/* Make EFI runtime service code area executable */

	for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {

		md = p;
@@ -476,6 +473,7 @@ void __init efi_enter_virtual_mode(void) 
	efi.get_next_high_mono_count = virt_efi_get_next_high_mono_count;

	efi.reset_system = virt_efi_reset_system;

	efi.set_virtual_address_map = virt_efi_set_virtual_address_map;

	if (__supported_pte_mask & _PAGE_NX)

		runtime_code_page_mkexec();

	early_iounmap(memmap.map, memmap.nr_map * memmap.desc_size);

	memmap.map = NULL;

arch/x86/kernel/efi_64.c

+13 −19
Original line number Diff line number Diff line
@@ -35,6 +35,7 @@ 
#include <asm/tlbflush.h>

#include <asm/proto.h>

#include <asm/efi.h>

#include <asm/cacheflush.h>



static pgd_t save_pgd __initdata;

static unsigned long efi_flags __initdata;
@@ -43,22 +44,15 @@ static void __init early_mapping_set_exec(unsigned long start, 
					  unsigned long end,

					  int executable)

{

	pte_t *kpte;

	unsigned int level;

	unsigned long num_pages;



	while (start < end) {

		kpte = lookup_address((unsigned long)__va(start), &level);

		BUG_ON(!kpte);

	start &= PMD_MASK;

	end = (end + PMD_SIZE - 1) & PMD_MASK;

	num_pages = (end - start) >> PAGE_SHIFT;

	if (executable)

			set_pte(kpte, pte_mkexec(*kpte));

		set_memory_x((unsigned long)__va(start), num_pages);

	else

			set_pte(kpte, __pte((pte_val(*kpte) | _PAGE_NX) & \

					    __supported_pte_mask));

		if (level == PG_LEVEL_4K)

			start = (start + PAGE_SIZE) & PAGE_MASK;

		else

			start = (start + PMD_SIZE) & PMD_MASK;

	}

		set_memory_nx((unsigned long)__va(start), num_pages);

}



static void __init early_runtime_code_mapping_set_exec(int executable)
@@ -74,7 +68,7 @@ static void __init early_runtime_code_mapping_set_exec(int executable) 
		md = p;

		if (md->type == EFI_RUNTIME_SERVICES_CODE) {

			unsigned long end;

			end = md->phys_addr + (md->num_pages << PAGE_SHIFT);

			end = md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT);

			early_mapping_set_exec(md->phys_addr, end, executable);

		}

	}
@@ -84,8 +78,8 @@ void __init efi_call_phys_prelog(void) 
{

	unsigned long vaddress;



	local_irq_save(efi_flags);

	early_runtime_code_mapping_set_exec(1);

	local_irq_save(efi_flags);

	vaddress = (unsigned long)__va(0x0UL);

	save_pgd = *pgd_offset_k(0x0UL);

	set_pgd(pgd_offset_k(0x0UL), *pgd_offset_k(vaddress));
@@ -98,9 +92,9 @@ void __init efi_call_phys_epilog(void) 
	 * After the lock is released, the original page table is restored.

	 */

	set_pgd(pgd_offset_k(0x0UL), save_pgd);

	early_runtime_code_mapping_set_exec(0);

	__flush_tlb_all();

	local_irq_restore(efi_flags);

	early_runtime_code_mapping_set_exec(0);

}



void __init efi_reserve_bootmem(void)

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