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| author | Michael Brown | 2017-06-15 15:50:20 +0200 |
|---|---|---|
| committer | Michael Brown | 2017-06-16 02:17:48 +0200 |
| commit | a6a5825f8d658834610de31b7b9be2e7d0a8804e (patch) | |
| tree | f51a8b343176bbf7c31483006060e93dc0161924 /src/arch/x86/include | |
| parent | [ecm] Display invalid MAC address strings in debug messages (diff) | |
| download | ipxe-a6a5825f8d658834610de31b7b9be2e7d0a8804e.tar.gz ipxe-a6a5825f8d658834610de31b7b9be2e7d0a8804e.tar.xz ipxe-a6a5825f8d658834610de31b7b9be2e7d0a8804e.zip | |
[cpuid] Allow input %ecx value to be specified
For some CPUID leaves (e.g. %eax=0x00000004), the result depends on
the input value of %ecx. Allow this subfunction number to be
specified as a parameter to the cpuid() wrapper.
The subfunction number is exposed via the ${cpuid/...} settings
mechanism using the syntax
${cpuid/<subfunction>.0x40.<register>.<function>}
e.g.
${cpuid/0.0x40.0.0x0000000b}
${cpuid/1.0x40.0.0x0000000b}
to retrieve the CPU topology information.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Diffstat (limited to 'src/arch/x86/include')
| -rw-r--r-- | src/arch/x86/include/ipxe/cpuid.h | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/src/arch/x86/include/ipxe/cpuid.h b/src/arch/x86/include/ipxe/cpuid.h index a9df9f0de..0ae572da4 100644 --- a/src/arch/x86/include/ipxe/cpuid.h +++ b/src/arch/x86/include/ipxe/cpuid.h @@ -66,19 +66,20 @@ struct x86_features { /** * Issue CPUID instruction * - * @v function CPUID function + * @v function CPUID function (input via %eax) + * @v subfunction CPUID subfunction (input via %ecx) * @v eax Output via %eax * @v ebx Output via %ebx * @v ecx Output via %ecx * @v edx Output via %edx */ static inline __attribute__ (( always_inline )) void -cpuid ( uint32_t function, uint32_t *eax, uint32_t *ebx, uint32_t *ecx, - uint32_t *edx ) { +cpuid ( uint32_t function, uint32_t subfunction, uint32_t *eax, uint32_t *ebx, + uint32_t *ecx, uint32_t *edx ) { __asm__ ( "cpuid" : "=a" ( *eax ), "=b" ( *ebx ), "=c" ( *ecx ), "=d" ( *edx ) - : "0" ( function ) ); + : "0" ( function ), "2" ( subfunction ) ); } extern int cpuid_supported ( uint32_t function ); |