diff options
Diffstat (limited to 'arch/i386/kernel')
| -rw-r--r-- | arch/i386/kernel/verify_cpu.S | 65 |
1 files changed, 65 insertions, 0 deletions
diff --git a/arch/i386/kernel/verify_cpu.S b/arch/i386/kernel/verify_cpu.S new file mode 100644 index 0000000..e51a869 --- /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 |