1 files changed, 20 insertions, 0 deletions

diff --git a/arch/x86/boot/cpucheck.c b/arch/x86/boot/cpucheck.c
index 100a9a10076a..f0d0b20fe149 100644
--- a/arch/x86/boot/cpucheck.c
+++ b/arch/x86/boot/cpucheck.c
@@ -67,6 +67,13 @@ static int is_transmeta(void)
                cpu_vendor[2] == A32('M', 'x', '8', '6');
 }
 
+static int is_intel(void)
+{
+        return cpu_vendor[0] == A32('G', 'e', 'n', 'u') &&
+               cpu_vendor[1] == A32('i', 'n', 'e', 'I') &&
+               cpu_vendor[2] == A32('n', 't', 'e', 'l');
+}
+
 /* Returns a bitmask of which words we have error bits in */
 static int check_cpuflags(void)
 {
@@ -153,6 +160,19 @@ int check_cpu(int *cpu_level_ptr, int *req_level_ptr, u32 **err_flags_ptr)
                 asm("wrmsr" : : "a" (eax), "d" (edx), "c" (ecx));
 
                 err = check_cpuflags();
+        } else if (err == 0x01 &&
+                   !(err_flags[0] & ~(1 << X86_FEATURE_PAE)) &&
+                   is_intel() && cpu.level == 6 &&
+                   (cpu.model == 9 || cpu.model == 13)) {
+                /* PAE is disabled on this Pentium M but can be forced */
+                if (cmdline_find_option_bool("forcepae")) {
+                        puts("WARNING: Forcing PAE in CPU flags\n");
+                        set_bit(X86_FEATURE_PAE, cpu.flags);
+                        err = check_cpuflags();
+                }
+                else {
+                        puts("WARNING: PAE disabled. Use parameter 'forcepae' to enable at your own risk!\n");
+                }
         }
 
         if (err_flags_ptr)