tools/perf/arch/x86/util/cpuid.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef PERF_CPUID_H
   3 #define PERF_CPUID_H 1
   4
   5
   6 static inline void
   7 cpuid(unsigned int op, unsigned int op2, unsigned int *a, unsigned int *b,
   8         unsigned int *c, unsigned int *d)
   9 {
  10         /*
  11          * Preserve %ebx/%rbx register by either placing it in %rdi or saving it
  12          * on the stack - x86-64 needs to avoid the stack red zone. In PIC
  13          * compilations %ebx contains the address of the global offset
  14          * table. %rbx is occasionally used to address stack variables in
  15          * presence of dynamic allocas.
  16          */
  17         asm(
  18 #if defined(__x86_64__)
  19                 "mov %%rbx, %%rdi\n"
  20                 "cpuid\n"
  21                 "xchg %%rdi, %%rbx\n"
  22 #else
  23                 "pushl %%ebx\n"
  24                 "cpuid\n"
  25                 "movl %%ebx, %%edi\n"
  26                 "popl %%ebx\n"
  27 #endif
  28                 : "=a"(*a), "=D"(*b), "=c"(*c), "=d"(*d)
  29                 : "a"(op), "2"(op2));
  30 }
  31
  32 void get_cpuid_0(char *vendor, unsigned int *lvl);
  33
  34 #endif