arch/x86/include/asm/apm.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  *  Machine specific APM BIOS functions for generic.
   4  *  Split out from apm.c by Osamu Tomita <tomita@cinet.co.jp>
   5  */
   6
   7 #ifndef _ASM_X86_MACH_DEFAULT_APM_H
   8 #define _ASM_X86_MACH_DEFAULT_APM_H
   9
  10 #ifdef APM_ZERO_SEGS
  11 #       define APM_DO_ZERO_SEGS \
  12                 "pushl %%ds\n\t" \
  13                 "pushl %%es\n\t" \
  14                 "xorl %%edx, %%edx\n\t" \
  15                 "mov %%dx, %%ds\n\t" \
  16                 "mov %%dx, %%es\n\t" \
  17                 "mov %%dx, %%fs\n\t" \
  18                 "mov %%dx, %%gs\n\t"
  19 #       define APM_DO_POP_SEGS \
  20                 "popl %%es\n\t" \
  21                 "popl %%ds\n\t"
  22 #else
  23 #       define APM_DO_ZERO_SEGS
  24 #       define APM_DO_POP_SEGS
  25 #endif
  26
  27 static inline void apm_bios_call_asm(u32 func, u32 ebx_in, u32 ecx_in,
  28                                         u32 *eax, u32 *ebx, u32 *ecx,
  29                                         u32 *edx, u32 *esi)
  30 {
  31         /*
  32          * N.B. We do NOT need a cld after the BIOS call
  33          * because we always save and restore the flags.
  34          */
  35         __asm__ __volatile__(APM_DO_ZERO_SEGS
  36                 "pushl %%edi\n\t"
  37                 "pushl %%ebp\n\t"
  38                 ANNOTATE_RETPOLINE_SAFE /* FRBS */
  39                 "lcall *%%cs:apm_bios_entry\n\t"
  40                 "setc %%al\n\t"
  41                 "popl %%ebp\n\t"
  42                 "popl %%edi\n\t"
  43                 APM_DO_POP_SEGS
  44                 : "=a" (*eax), "=b" (*ebx), "=c" (*ecx), "=d" (*edx),
  45                   "=S" (*esi)
  46                 : "a" (func), "b" (ebx_in), "c" (ecx_in)
  47                 : "memory", "cc");
  48 }
  49
  50 static inline bool apm_bios_call_simple_asm(u32 func, u32 ebx_in,
  51                                             u32 ecx_in, u32 *eax)
  52 {
  53         int     cx, dx, si;
  54         bool    error;
  55
  56         /*
  57          * N.B. We do NOT need a cld after the BIOS call
  58          * because we always save and restore the flags.
  59          */
  60         __asm__ __volatile__(APM_DO_ZERO_SEGS
  61                 "pushl %%edi\n\t"
  62                 "pushl %%ebp\n\t"
  63                 ANNOTATE_RETPOLINE_SAFE /* FRBS */
  64                 "lcall *%%cs:apm_bios_entry\n\t"
  65                 "setc %%bl\n\t"
  66                 "popl %%ebp\n\t"
  67                 "popl %%edi\n\t"
  68                 APM_DO_POP_SEGS
  69                 : "=a" (*eax), "=b" (error), "=c" (cx), "=d" (dx),
  70                   "=S" (si)
  71                 : "a" (func), "b" (ebx_in), "c" (ecx_in)
  72                 : "memory", "cc");
  73         return error;
  74 }
  75
  76 #endif /* _ASM_X86_MACH_DEFAULT_APM_H */