[patch] Modifications for the cpuid Asembly code

powertop-1.10-pic.diff (text/plain), 1.09 KB, created by Attila Tóth on 2008-09-13 20:57:13 UTC

diff -urN powertop-1.10-orig/intelcstates.c powertop-1.10-atoth/intelcstates.c
--- powertop-1.10-orig/intelcstates.c	2008-06-10 22:18:45.000000000 +0200
+++ powertop-1.10-atoth/intelcstates.c	2008-09-13 22:23:01.000000000 +0200
@@ -44,10 +44,17 @@
                         unsigned int *ecx,
                         unsigned int *edx)
 {
-        /* call the cpuid instruction with the registers as input and output */
-        __asm__("cpuid"
+        /* call the cpuid instruction with the registers as input and output
+	 * modification by Dwokfur based on Sam Hocevar's discussion on
+	 * how to make Assemly code PIC compatible:
+	 * http://sam.zoy.org/blog/2007-04-13-shlib-with-non-pic-code-have-inline-assembly-and-pic-mix-well
+	 */
+        __asm__("pushl %%ebx	\n\t" /* save %ebx */
+		"cpuid		\n\t"
+		"movl %%ebx, %1	\n\t" /* save what cpuid just put in %ebx */
+		"popl %%ebx	\n\t" /* restore the old %ebx */
                 : "=a" (*eax),
-                  "=b" (*ebx),
+                  "=r" (*ebx),
                   "=c" (*ecx),
                   "=d" (*edx)
                 : "0" (*eax),