dc60c24146
__cdecl is a misleading name, since it currently encapsulates both cdecl and regparm(0) attributes. Rename to __asmcall.
189 lines
5.8 KiB
C
189 lines
5.8 KiB
C
/*
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* Copyright (C) 2008 Daniel Verkamp <daniel@drv.nu>.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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/**
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* @file SYSLINUX COM32 helpers
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*
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*/
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#include <stdint.h>
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#include <realmode.h>
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#include <comboot.h>
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#include <assert.h>
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#include <gpxe/uaccess.h>
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static com32sys_t __bss16 ( com32_regs );
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#define com32_regs __use_data16 ( com32_regs )
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static uint8_t __bss16 ( com32_int_vector );
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#define com32_int_vector __use_data16 ( com32_int_vector )
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static uint32_t __bss16 ( com32_farcall_proc );
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#define com32_farcall_proc __use_data16 ( com32_farcall_proc )
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uint16_t __bss16 ( com32_saved_sp );
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/**
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* Interrupt call helper
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*/
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void __asmcall com32_intcall ( uint8_t interrupt, physaddr_t inregs_phys, physaddr_t outregs_phys ) {
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memcpy_user ( virt_to_user( &com32_regs ), 0,
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phys_to_user ( inregs_phys ), 0,
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sizeof(com32sys_t) );
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com32_int_vector = interrupt;
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__asm__ __volatile__ (
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REAL_CODE ( /* Save all registers */
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"pushal\n\t"
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"pushw %%ds\n\t"
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"pushw %%es\n\t"
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"pushw %%fs\n\t"
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"pushw %%gs\n\t"
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/* Mask off unsafe flags */
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"movl (com32_regs + 40), %%eax\n\t"
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"andl $0x200cd7, %%eax\n\t"
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"movl %%eax, (com32_regs + 40)\n\t"
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/* Load com32_regs into the actual registers */
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"movw %%sp, %%ss:(com32_saved_sp)\n\t"
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"movw $com32_regs, %%sp\n\t"
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"popw %%gs\n\t"
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"popw %%fs\n\t"
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"popw %%es\n\t"
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"popw %%ds\n\t"
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"popal\n\t"
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"popfl\n\t"
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"movw %%ss:(com32_saved_sp), %%sp\n\t"
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/* patch INT instruction */
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"pushw %%ax\n\t"
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"movb %%ss:(com32_int_vector), %%al\n\t"
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"movb %%al, %%cs:(com32_intcall_instr + 1)\n\t"
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/* perform a jump to avoid problems with cache
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* consistency in self-modifying code on some CPUs (486)
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*/
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"jmp 1f\n"
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"1:\n\t"
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"popw %%ax\n\t"
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"com32_intcall_instr:\n\t"
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/* INT instruction to be patched */
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"int $0xFF\n\t"
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/* Copy regs back to com32_regs */
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"movw %%sp, %%ss:(com32_saved_sp)\n\t"
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"movw $(com32_regs + 44), %%sp\n\t"
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"pushfl\n\t"
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"pushal\n\t"
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"pushw %%ds\n\t"
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"pushw %%es\n\t"
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"pushw %%fs\n\t"
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"pushw %%gs\n\t"
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"movw %%ss:(com32_saved_sp), %%sp\n\t"
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/* Restore registers */
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"popw %%gs\n\t"
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"popw %%fs\n\t"
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"popw %%es\n\t"
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"popw %%ds\n\t"
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"popal\n\t")
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: : );
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if ( outregs_phys ) {
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memcpy_user ( phys_to_user ( outregs_phys ), 0,
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virt_to_user( &com32_regs ), 0,
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sizeof(com32sys_t) );
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}
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}
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/**
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* Farcall helper
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*/
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void __asmcall com32_farcall ( uint32_t proc, physaddr_t inregs_phys, physaddr_t outregs_phys ) {
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memcpy_user ( virt_to_user( &com32_regs ), 0,
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phys_to_user ( inregs_phys ), 0,
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sizeof(com32sys_t) );
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com32_farcall_proc = proc;
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__asm__ __volatile__ (
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REAL_CODE ( /* Save all registers */
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"pushal\n\t"
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"pushw %%ds\n\t"
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"pushw %%es\n\t"
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"pushw %%fs\n\t"
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"pushw %%gs\n\t"
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/* Mask off unsafe flags */
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"movl (com32_regs + 40), %%eax\n\t"
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"andl $0x200cd7, %%eax\n\t"
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"movl %%eax, (com32_regs + 40)\n\t"
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/* Load com32_regs into the actual registers */
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"movw %%sp, %%ss:(com32_saved_sp)\n\t"
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"movw $com32_regs, %%sp\n\t"
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"popw %%gs\n\t"
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"popw %%fs\n\t"
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"popw %%es\n\t"
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"popw %%ds\n\t"
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"popal\n\t"
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"popfl\n\t"
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"movw %%ss:(com32_saved_sp), %%sp\n\t"
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/* Call procedure */
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"lcall *%%ss:(com32_farcall_proc)\n\t"
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/* Copy regs back to com32_regs */
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"movw %%sp, %%ss:(com32_saved_sp)\n\t"
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"movw $(com32_regs + 44), %%sp\n\t"
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"pushfl\n\t"
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"pushal\n\t"
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"pushw %%ds\n\t"
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"pushw %%es\n\t"
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"pushw %%fs\n\t"
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"pushw %%gs\n\t"
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"movw %%ss:(com32_saved_sp), %%sp\n\t"
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/* Restore registers */
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"popw %%gs\n\t"
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"popw %%fs\n\t"
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"popw %%es\n\t"
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"popw %%ds\n\t"
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"popal\n\t")
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: : );
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if ( outregs_phys ) {
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memcpy_user ( phys_to_user ( outregs_phys ), 0,
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virt_to_user( &com32_regs ), 0,
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sizeof(com32sys_t) );
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}
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}
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/**
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* CDECL farcall helper
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*/
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int __asmcall com32_cfarcall ( uint32_t proc, physaddr_t stack, size_t stacksz ) {
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int32_t eax;
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copy_user_to_rm_stack ( phys_to_user ( stack ), stacksz );
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com32_farcall_proc = proc;
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__asm__ __volatile__ (
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REAL_CODE ( "lcall *%%ss:(com32_farcall_proc)\n\t" )
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: "=a" (eax)
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:
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: "ecx", "edx" );
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remove_user_from_rm_stack ( 0, stacksz );
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return eax;
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}
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