--- /dev/null
+/*
+ * 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., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+/**
+ * @file SYSLINUX COM32 helpers
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include <stdint.h>
+#include <realmode.h>
+#include <comboot.h>
+#include <assert.h>
+#include <ipxe/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;
+}
Code Review / kvmfornfv.git / blobdiff