[comboot] Support COMBOOT in 64-bit builds

Signed-off-by: Michael Brown <mcb30@ipxe.org>

1 files changed, 200 insertions, 0 deletions

diff --git a/src/arch/x86/interface/syslinux/com32_call.c b/src/arch/x86/interface/syslinux/com32_call.c
new file mode 100644
index 000000000..19fdbaff9
--- /dev/null
+++ b/src/arch/x86/interface/syslinux/com32_call.c
@@ -0,0 +1,200 @@
+/*
+ * 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 ) {
+
+	DBGC ( &com32_regs, "COM32 INT%x in %#08lx out %#08lx\n",
+	       interrupt, inregs_phys, 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 ) {
+
+	DBGC ( &com32_regs, "COM32 farcall %04x:%04x in %#08lx out %#08lx\n",
+	       ( proc >> 16 ), ( proc & 0xffff ), inregs_phys, 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;
+
+	DBGC ( &com32_regs, "COM32 cfarcall %04x:%04x params %#08lx+%#zx\n",
+	       ( proc >> 16 ), ( proc & 0xffff ), stack, stacksz );
+
+	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;
+}