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 #include <asm/nospec-branch.h> 11 12 #ifdef APM_ZERO_SEGS 13 # define APM_DO_ZERO_SEGS \ 14 "pushl %%ds\n\t" \ 15 "pushl %%es\n\t" \ 16 "xorl %%edx, %%edx\n\t" \ 17 "mov %%dx, %%ds\n\t" \ 18 "mov %%dx, %%es\n\t" \ 19 "mov %%dx, %%fs\n\t" \ 20 "mov %%dx, %%gs\n\t" 21 # define APM_DO_POP_SEGS \ 22 "popl %%es\n\t" \ 23 "popl %%ds\n\t" 24 #else 25 # define APM_DO_ZERO_SEGS 26 # define APM_DO_POP_SEGS 27 #endif 28 29 static inline void apm_bios_call_asm(u32 func, u32 ebx_in, u32 ecx_in, 30 u32 *eax, u32 *ebx, u32 *ecx, 31 u32 *edx, u32 *esi) 32 { 33 /* 34 * N.B. We do NOT need a cld after the BIOS call 35 * because we always save and restore the flags. 36 */ 37 firmware_restrict_branch_speculation_start(); 38 __asm__ __volatile__(APM_DO_ZERO_SEGS 39 "pushl %%edi\n\t" 40 "pushl %%ebp\n\t" 41 "lcall *%%cs:apm_bios_entry\n\t" 42 "setc %%al\n\t" 43 "popl %%ebp\n\t" 44 "popl %%edi\n\t" 45 APM_DO_POP_SEGS 46 : "=a" (*eax), "=b" (*ebx), "=c" (*ecx), "=d" (*edx), 47 "=S" (*esi) 48 : "a" (func), "b" (ebx_in), "c" (ecx_in) 49 : "memory", "cc"); 50 firmware_restrict_branch_speculation_end(); 51 } 52 53 static inline bool apm_bios_call_simple_asm(u32 func, u32 ebx_in, 54 u32 ecx_in, u32 *eax) 55 { 56 int cx, dx, si; 57 bool error; 58 59 /* 60 * N.B. We do NOT need a cld after the BIOS call 61 * because we always save and restore the flags. 62 */ 63 firmware_restrict_branch_speculation_start(); 64 __asm__ __volatile__(APM_DO_ZERO_SEGS 65 "pushl %%edi\n\t" 66 "pushl %%ebp\n\t" 67 "lcall *%%cs:apm_bios_entry\n\t" 68 "setc %%bl\n\t" 69 "popl %%ebp\n\t" 70 "popl %%edi\n\t" 71 APM_DO_POP_SEGS 72 : "=a" (*eax), "=b" (error), "=c" (cx), "=d" (dx), 73 "=S" (si) 74 : "a" (func), "b" (ebx_in), "c" (ecx_in) 75 : "memory", "cc"); 76 firmware_restrict_branch_speculation_end(); 77 return error; 78 } 79 80 #endif /* _ASM_X86_MACH_DEFAULT_APM_H */ 81