diff options
Diffstat (limited to 'contrib/syslinux-4.02/gpxe/src/arch/i386/interface/syslinux/com32_call.c')
| -rw-r--r-- | contrib/syslinux-4.02/gpxe/src/arch/i386/interface/syslinux/com32_call.c | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/contrib/syslinux-4.02/gpxe/src/arch/i386/interface/syslinux/com32_call.c b/contrib/syslinux-4.02/gpxe/src/arch/i386/interface/syslinux/com32_call.c new file mode 100644 index 0000000..d2c3f91 --- /dev/null +++ b/contrib/syslinux-4.02/gpxe/src/arch/i386/interface/syslinux/com32_call.c @@ -0,0 +1,190 @@ +/* + * 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; +} |