x86: keep the BIOS area executable

keep the BIOS area executable.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 22 insertions, 7 deletions

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 4589a1382fa1..effcd78d5f40 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -22,6 +22,27 @@ void clflush_cache_range(void *addr, int size)
 #include <asm/uaccess.h>
 #include <asm/pgalloc.h>
 
+/*
+ * We allow the BIOS range to be executable:
+ */
+#define BIOS_BEGIN              0x000a0000
+#define BIOS_END                0x00100000
+
+static inline pgprot_t check_exec(pgprot_t prot, unsigned long address)
+{
+        if (__pa(address) >= BIOS_BEGIN && __pa(address) < BIOS_END)
+                pgprot_val(prot) &= ~_PAGE_NX;
+        /*
+         * Better fail early if someone sets the kernel text to NX.
+         * Does not cover __inittext
+         */
+        BUG_ON(address >= (unsigned long)&_text &&
+                address < (unsigned long)&_etext &&
+               (pgprot_val(prot) & _PAGE_NX));
+
+        return prot;
+}
+
 pte_t *lookup_address(unsigned long address, int *level)
 {
         pgd_t *pgd = pgd_offset_k(address);
@@ -140,13 +161,7 @@ repeat:
         BUG_ON(PageLRU(kpte_page));
         BUG_ON(PageCompound(kpte_page));
 
-        /*
-         * Better fail early if someone sets the kernel text to NX.
-         * Does not cover __inittext
-         */
-        BUG_ON(address >= (unsigned long)&_text &&
-                address < (unsigned long)&_etext &&
-               (pgprot_val(prot) & _PAGE_NX));
+        prot = check_exec(prot, address);
 
         if (level == PG_LEVEL_4K) {
                 set_pte_atomic(kpte, mk_pte(page, canon_pgprot(prot)));