| /* |
| * Copyright (C) 2008 Daniel Verkamp <daniel@drv.nu>. |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public License as |
| * published by the Free Software Foundation; either version 2 of the |
| * License, or any later version. |
| * |
| * This program is distributed in the hope that it will be useful, but |
| * WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
| */ |
| |
| /** |
| * @file SYSLINUX COM32 helpers |
| * |
| */ |
| |
| FILE_LICENCE ( GPL2_OR_LATER ); |
| |
| #include <stdint.h> |
| #include <realmode.h> |
| #include <comboot.h> |
| #include <assert.h> |
| #include <gpxe/uaccess.h> |
| |
| static com32sys_t __bss16 ( com32_regs ); |
| #define com32_regs __use_data16 ( com32_regs ) |
| |
| static uint8_t __bss16 ( com32_int_vector ); |
| #define com32_int_vector __use_data16 ( com32_int_vector ) |
| |
| static uint32_t __bss16 ( com32_farcall_proc ); |
| #define com32_farcall_proc __use_data16 ( com32_farcall_proc ) |
| |
| uint16_t __bss16 ( com32_saved_sp ); |
| |
| /** |
| * Interrupt call helper |
| */ |
| void __asmcall com32_intcall ( uint8_t interrupt, physaddr_t inregs_phys, physaddr_t outregs_phys ) { |
| |
| memcpy_user ( virt_to_user( &com32_regs ), 0, |
| phys_to_user ( inregs_phys ), 0, |
| sizeof(com32sys_t) ); |
| |
| com32_int_vector = interrupt; |
| |
| __asm__ __volatile__ ( |
| REAL_CODE ( /* Save all registers */ |
| "pushal\n\t" |
| "pushw %%ds\n\t" |
| "pushw %%es\n\t" |
| "pushw %%fs\n\t" |
| "pushw %%gs\n\t" |
| /* Mask off unsafe flags */ |
| "movl (com32_regs + 40), %%eax\n\t" |
| "andl $0x200cd7, %%eax\n\t" |
| "movl %%eax, (com32_regs + 40)\n\t" |
| /* Load com32_regs into the actual registers */ |
| "movw %%sp, %%ss:(com32_saved_sp)\n\t" |
| "movw $com32_regs, %%sp\n\t" |
| "popw %%gs\n\t" |
| "popw %%fs\n\t" |
| "popw %%es\n\t" |
| "popw %%ds\n\t" |
| "popal\n\t" |
| "popfl\n\t" |
| "movw %%ss:(com32_saved_sp), %%sp\n\t" |
| /* patch INT instruction */ |
| "pushw %%ax\n\t" |
| "movb %%ss:(com32_int_vector), %%al\n\t" |
| "movb %%al, %%cs:(com32_intcall_instr + 1)\n\t" |
| /* perform a jump to avoid problems with cache |
| * consistency in self-modifying code on some CPUs (486) |
| */ |
| "jmp 1f\n" |
| "1:\n\t" |
| "popw %%ax\n\t" |
| "com32_intcall_instr:\n\t" |
| /* INT instruction to be patched */ |
| "int $0xFF\n\t" |
| /* Copy regs back to com32_regs */ |
| "movw %%sp, %%ss:(com32_saved_sp)\n\t" |
| "movw $(com32_regs + 44), %%sp\n\t" |
| "pushfl\n\t" |
| "pushal\n\t" |
| "pushw %%ds\n\t" |
| "pushw %%es\n\t" |
| "pushw %%fs\n\t" |
| "pushw %%gs\n\t" |
| "movw %%ss:(com32_saved_sp), %%sp\n\t" |
| /* Restore registers */ |
| "popw %%gs\n\t" |
| "popw %%fs\n\t" |
| "popw %%es\n\t" |
| "popw %%ds\n\t" |
| "popal\n\t") |
| : : ); |
| |
| if ( outregs_phys ) { |
| memcpy_user ( phys_to_user ( outregs_phys ), 0, |
| virt_to_user( &com32_regs ), 0, |
| sizeof(com32sys_t) ); |
| } |
| } |
| |
| /** |
| * Farcall helper |
| */ |
| void __asmcall com32_farcall ( uint32_t proc, physaddr_t inregs_phys, physaddr_t outregs_phys ) { |
| |
| memcpy_user ( virt_to_user( &com32_regs ), 0, |
| phys_to_user ( inregs_phys ), 0, |
| sizeof(com32sys_t) ); |
| |
| com32_farcall_proc = proc; |
| |
| __asm__ __volatile__ ( |
| REAL_CODE ( /* Save all registers */ |
| "pushal\n\t" |
| "pushw %%ds\n\t" |
| "pushw %%es\n\t" |
| "pushw %%fs\n\t" |
| "pushw %%gs\n\t" |
| /* Mask off unsafe flags */ |
| "movl (com32_regs + 40), %%eax\n\t" |
| "andl $0x200cd7, %%eax\n\t" |
| "movl %%eax, (com32_regs + 40)\n\t" |
| /* Load com32_regs into the actual registers */ |
| "movw %%sp, %%ss:(com32_saved_sp)\n\t" |
| "movw $com32_regs, %%sp\n\t" |
| "popw %%gs\n\t" |
| "popw %%fs\n\t" |
| "popw %%es\n\t" |
| "popw %%ds\n\t" |
| "popal\n\t" |
| "popfl\n\t" |
| "movw %%ss:(com32_saved_sp), %%sp\n\t" |
| /* Call procedure */ |
| "lcall *%%ss:(com32_farcall_proc)\n\t" |
| /* Copy regs back to com32_regs */ |
| "movw %%sp, %%ss:(com32_saved_sp)\n\t" |
| "movw $(com32_regs + 44), %%sp\n\t" |
| "pushfl\n\t" |
| "pushal\n\t" |
| "pushw %%ds\n\t" |
| "pushw %%es\n\t" |
| "pushw %%fs\n\t" |
| "pushw %%gs\n\t" |
| "movw %%ss:(com32_saved_sp), %%sp\n\t" |
| /* Restore registers */ |
| "popw %%gs\n\t" |
| "popw %%fs\n\t" |
| "popw %%es\n\t" |
| "popw %%ds\n\t" |
| "popal\n\t") |
| : : ); |
| |
| if ( outregs_phys ) { |
| memcpy_user ( phys_to_user ( outregs_phys ), 0, |
| virt_to_user( &com32_regs ), 0, |
| sizeof(com32sys_t) ); |
| } |
| } |
| |
| /** |
| * CDECL farcall helper |
| */ |
| int __asmcall com32_cfarcall ( uint32_t proc, physaddr_t stack, size_t stacksz ) { |
| int32_t eax; |
| |
| copy_user_to_rm_stack ( phys_to_user ( stack ), stacksz ); |
| com32_farcall_proc = proc; |
| |
| __asm__ __volatile__ ( |
| REAL_CODE ( "lcall *%%ss:(com32_farcall_proc)\n\t" ) |
| : "=a" (eax) |
| : |
| : "ecx", "edx" ); |
| |
| remove_user_from_rm_stack ( 0, stacksz ); |
| |
| return eax; |
| } |
