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: Huang Ying <ying.huang@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/arch/x86/kernel/efi.c b/arch/x86/kernel/efi.c
index b4d523276f404069eeb49815c86ed68f3b6d10ee..cbdf9bacc5758e76132ca77dcc5a36d27ccf01fb 100644 (file)
--- a/arch/x86/kernel/efi.c
+++ b/arch/x86/kernel/efi.c
@@ -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;
@@ -476,7 +473,8 @@ 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;
-       runtime_code_page_mkexec();
+       if (__supported_pte_mask & _PAGE_NX)
+               runtime_code_page_mkexec();
        early_iounmap(memmap.map, memmap.nr_map * memmap.desc_size);
        memmap.map = NULL;
 }

diff --git a/arch/x86/kernel/efi_64.c b/arch/x86/kernel/efi_64.c
index 09d5c23309342779ca955e641a408657a7395ec8..d143a1e76b301737c6fc34f2a0d6da656b787038 100644 (file)
--- a/arch/x86/kernel/efi_64.c
+++ b/arch/x86/kernel/efi_64.c
@@ -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;
-
-       while (start < end) {
-               kpte = lookup_address((unsigned long)__va(start), &level);
-               BUG_ON(!kpte);
-               if (executable)
-                       set_pte(kpte, pte_mkexec(*kpte));
-               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;
-       }
+       unsigned long num_pages;
+
+       start &= PMD_MASK;
+       end = (end + PMD_SIZE - 1) & PMD_MASK;
+       num_pages = (end - start) >> PAGE_SHIFT;
+       if (executable)
+               set_memory_x((unsigned long)__va(start), num_pages);
+       else
+               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)