3 files changed, 102 insertions, 2 deletions

diff --git a/arch/i386/Kconfig.cpu b/arch/i386/Kconfig.cpu
index b1af9f50a143..dce6124cb842 100644
--- a/arch/i386/Kconfig.cpu
+++ b/arch/i386/Kconfig.cpu
@@ -240,14 +240,19 @@ config X86_L1_CACHE_SHIFT
         default "5" if MWINCHIP3D || MWINCHIP2 || MWINCHIPC6 || MCRUSOE || MEFFICEON || MCYRIXIII || MK6 || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || M586 || MVIAC3_2 || MGEODE_LX
         default "6" if MK7 || MK8 || MPENTIUMM || MCORE2 || MVIAC7
 
+config X86_XADD
+        bool
+        depends on !M386
+        default y
+
 config RWSEM_GENERIC_SPINLOCK
         bool
-        depends on M386
+        depends on !X86_XADD
         default y
 
 config RWSEM_XCHGADD_ALGORITHM
         bool
-        depends on !M386
+        depends on X86_XADD
         default y
 
 config ARCH_HAS_ILOG2_U32
@@ -331,3 +336,16 @@ config X86_TSC
         bool
         depends on (MWINCHIP3D || MWINCHIP2 || MCRUSOE || MEFFICEON || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || MK8 || MVIAC3_2 || MVIAC7 || MGEODEGX1 || MGEODE_LX || MCORE2) && !X86_NUMAQ
         default y
+
+# this should be set for all -march=.. options where the compiler
+# generates cmov.
+config X86_CMOV
+        bool
+        depends on (MK7 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MVIAC3_2 || MVIAC7)
+        default y
+
+config X86_MINIMUM_CPU_MODEL
+        int
+        default "4" if X86_XADD || X86_CMPXCHG || X86_BSWAP
+        default "0"
+
diff --git a/arch/i386/boot/setup.S b/arch/i386/boot/setup.S
index b74b7f40b79c..f8b3b9cda2b1 100644
--- a/arch/i386/boot/setup.S
+++ b/arch/i386/boot/setup.S
@@ -302,7 +302,24 @@ good_sig:
 
 loader_panic_mess: .string "Wrong loader, giving up..."
 
+# check minimum cpuid
+# we do this here because it is the last place we can actually
+# show a user visible error message. Later the video modus
+# might be already messed up.
 loader_ok:
+        call verify_cpu
+        testl  %eax,%eax
+        jz      cpu_ok
+        lea     cpu_panic_mess,%si
+        call    prtstr
+1:      jmp     1b
+
+cpu_panic_mess:
+        .asciz  "PANIC: CPU too old for this kernel."
+
+#include "../kernel/verify_cpu.S"
+
+cpu_ok:
 # Get memory size (extended mem, kB)
 
         xorl    %eax, %eax
diff --git a/arch/i386/kernel/verify_cpu.S b/arch/i386/kernel/verify_cpu.S
new file mode 100644
index 000000000000..e51a8695d54e
--- /dev/null
+++ b/arch/i386/kernel/verify_cpu.S
@@ -0,0 +1,65 @@
+/* Check if CPU has some minimum CPUID bits
+   This runs in 16bit mode so that the caller can still use the BIOS
+   to output errors on the screen */
+#include <asm/cpufeature.h>
+
+verify_cpu:
+        pushfl                          # Save caller passed flags
+        pushl   $0                      # Kill any dangerous flags
+        popfl
+
+#if CONFIG_X86_MINIMUM_CPU_MODEL >= 4
+        pushfl
+        orl     $(1<<18),(%esp)         # try setting AC
+        popfl
+        pushfl
+        popl    %eax
+        testl   $(1<<18),%eax
+        jz      bad
+#endif
+#if REQUIRED_MASK1 != 0
+        pushfl                          # standard way to check for cpuid
+        popl    %eax
+        movl    %eax,%ebx
+        xorl    $0x200000,%eax
+        pushl   %eax
+        popfl
+        pushfl
+        popl    %eax
+        cmpl    %eax,%ebx
+        pushfl                          # standard way to check for cpuid
+        popl    %eax
+        movl    %eax,%ebx
+        xorl    $0x200000,%eax
+        pushl   %eax
+        popfl
+        pushfl
+        popl    %eax
+        cmpl    %eax,%ebx
+        jz      bad                     # REQUIRED_MASK1 != 0 requires CPUID
+
+        movl    $0x0,%eax               # See if cpuid 1 is implemented
+        cpuid
+        cmpl    $0x1,%eax
+        jb      bad                     # no cpuid 1
+
+        movl    $0x1,%eax               # Does the cpu have what it takes
+        cpuid
+
+#if CONFIG_X86_MINIMUM_CPU_MODEL > 4
+#error  add proper model checking here
+#endif
+
+        andl    $REQUIRED_MASK1,%edx
+        xorl    $REQUIRED_MASK1,%edx
+        jnz     bad
+#endif /* REQUIRED_MASK1 */
+
+        popfl
+        xor     %eax,%eax
+        ret
+
+bad:
+        popfl
+        movl    $1,%eax
+        ret