6 files changed, 169 insertions, 3 deletions

diff --git a/arch/x86/boot/Makefile b/arch/x86/boot/Makefile
index 6633b6e7505a..658bc525cac7 100644
--- a/arch/x86/boot/Makefile
+++ b/arch/x86/boot/Makefile
@@ -26,9 +26,10 @@ targets		:= vmlinux.bin setup.bin setup.elf bzImage
 targets         += fdimage fdimage144 fdimage288 image.iso mtools.conf
 subdir-         := compressed
 
-setup-y         += a20.o cmdline.o copy.o cpu.o cpucheck.o edd.o
+setup-y         += a20.o bioscall.o cmdline.o copy.o cpu.o cpucheck.o edd.o
 setup-y         += header.o main.o mca.o memory.o pm.o pmjump.o
-setup-y         += printf.o string.o tty.o video.o video-mode.o version.o
+setup-y         += printf.o regs.o string.o tty.o video.o video-mode.o
+setup-y         += version.o
 setup-$(CONFIG_X86_APM_BOOT) += apm.o
 
 # The link order of the video-*.o modules can matter.  In particular,
diff --git a/arch/x86/boot/bioscall.S b/arch/x86/boot/bioscall.S
new file mode 100644
index 000000000000..22b4b3efb9f9
--- /dev/null
+++ b/arch/x86/boot/bioscall.S
@@ -0,0 +1,82 @@
+/* -----------------------------------------------------------------------
+ *
+ *   Copyright 2009 Intel Corporation; author H. Peter Anvin
+ *
+ *   This file is part of the Linux kernel, and is made available under
+ *   the terms of the GNU General Public License version 2 or (at your
+ *   option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * "Glove box" for BIOS calls.  Avoids the constant problems with BIOSes
+ * touching memory they shouldn't be.
+ */
+
+        .code16
+        .text
+        .globl  intcall
+        .type   intcall, @function
+intcall:
+        /* Self-modify the INT instruction.  Ugly, but works. */
+        cmpb    %al, 3f
+        je      1f
+        movb    %al, 3f
+        jmp     1f              /* Synchronize pipeline */
+1:
+        /* Save state */
+        pushfl
+        pushw   %fs
+        pushw   %gs
+        pushal
+
+        /* Copy input state to stack frame */
+        subw    $44, %sp
+        movw    %dx, %si
+        movw    %sp, %di
+        movw    $11, %cx
+        rep; movsd
+
+        /* Pop full state from the stack */
+        popal
+        popw    %gs
+        popw    %fs
+        popw    %es
+        popw    %ds
+        popfl
+
+        /* Actual INT */
+        .byte   0xcd            /* INT opcode */
+3:      .byte   0
+
+        /* Push full state to the stack */
+        pushfl
+        pushw   %ds
+        pushw   %es
+        pushw   %fs
+        pushw   %gs
+        pushal
+
+        /* Re-establish C environment invariants */
+        cld
+        movzwl  %sp, %esp
+        movw    %cs, %ax
+        movw    %ax, %ds
+        movw    %ax, %es
+
+        /* Copy output state from stack frame */
+        movw    68(%esp), %di   /* Original %cx == 3rd argument */
+        andw    %di, %di
+        jz      4f
+        movw    %sp, %si
+        movw    $11, %cx
+        rep; movsd
+4:      addw    $44, %sp
+
+        /* Restore state and return */
+        popal
+        popw    %gs
+        popw    %fs
+        popfl
+        retl
+        .size   intcall, .-intcall
diff --git a/arch/x86/boot/boot.h b/arch/x86/boot/boot.h
index 7b2692e897e5..98239d2658f2 100644
--- a/arch/x86/boot/boot.h
+++ b/arch/x86/boot/boot.h
@@ -2,6 +2,7 @@
  *
  *   Copyright (C) 1991, 1992 Linus Torvalds
  *   Copyright 2007 rPath, Inc. - All Rights Reserved
+ *   Copyright 2009 Intel Corporation; author H. Peter Anvin
  *
  *   This file is part of the Linux kernel, and is made available under
  *   the terms of the GNU General Public License version 2.
@@ -26,6 +27,7 @@
 #include <asm/setup.h>
 #include "bitops.h"
 #include <asm/cpufeature.h>
+#include <asm/processor-flags.h>
 
 /* Useful macros */
 #define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
@@ -241,6 +243,49 @@ int enable_a20(void);
 /* apm.c */
 int query_apm_bios(void);
 
+/* bioscall.c */
+struct biosregs {
+        union {
+                struct {
+                        u32 edi;
+                        u32 esi;
+                        u32 ebp;
+                        u32 _esp;
+                        u32 ebx;
+                        u32 edx;
+                        u32 ecx;
+                        u32 eax;
+                        u32 _fsgs;
+                        u32 _dses;
+                        u32 eflags;
+                };
+                struct {
+                        u16 di, hdi;
+                        u16 si, hsi;
+                        u16 bp, hbp;
+                        u16 _sp, _hsp;
+                        u16 bx, hbx;
+                        u16 dx, hdx;
+                        u16 cx, hcx;
+                        u16 ax, hax;
+                        u16 gs, fs;
+                        u16 es, ds;
+                        u16 flags, hflags;
+                };
+                struct {
+                        u8 dil, dih, edi2, edi3;
+                        u8 sil, sih, esi2, esi3;
+                        u8 bpl, bph, ebp2, ebp3;
+                        u8 _spl, _sph, _esp2, _esp3;
+                        u8 bl, bh, ebx2, ebx3;
+                        u8 dl, dh, edx2, edx3;
+                        u8 cl, ch, ecx2, ecx3;
+                        u8 al, ah, eax2, eax3;
+                };
+        };
+};
+void intcall(u8 int_no, const struct biosregs *ireg, struct biosregs *oreg);
+
 /* cmdline.c */
 int cmdline_find_option(const char *option, char *buffer, int bufsize);
 int cmdline_find_option_bool(const char *option);
@@ -279,6 +324,9 @@ int sprintf(char *buf, const char *fmt, ...);
 int vsprintf(char *buf, const char *fmt, va_list args);
 int printf(const char *fmt, ...);
 
+/* regs.c */
+void initregs(struct biosregs *regs);
+
 /* string.c */
 int strcmp(const char *str1, const char *str2);
 size_t strnlen(const char *s, size_t maxlen);
diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S
index 5d84d1c74e4c..486d97fa7f4d 100644
--- a/arch/x86/boot/header.S
+++ b/arch/x86/boot/header.S
@@ -221,7 +221,7 @@ setup_data:		.quad 0			# 64-bit physical pointer to
 
 # End of setup header #####################################################
 
-        .section ".inittext", "ax"
+        .section ".entrytext", "ax"
 start_of_setup:
 #ifdef SAFE_RESET_DISK_CONTROLLER
 # Reset the disk controller.
diff --git a/arch/x86/boot/regs.c b/arch/x86/boot/regs.c
new file mode 100644
index 000000000000..958019b1cfa5
--- /dev/null
+++ b/arch/x86/boot/regs.c
@@ -0,0 +1,29 @@
+/* -----------------------------------------------------------------------
+ *
+ *   Copyright 2009 Intel Corporation; author H. Peter Anvin
+ *
+ *   This file is part of the Linux kernel, and is made available under
+ *   the terms of the GNU General Public License version 2 or (at your
+ *   option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * Simple helper function for initializing a register set.
+ *
+ * Note that this sets EFLAGS_CF in the input register set; this
+ * makes it easier to catch functions which do nothing but don't
+ * explicitly set CF.
+ */
+
+#include "boot.h"
+
+void initregs(struct biosregs *reg)
+{
+        memset(reg, 0, sizeof *reg);
+        reg->eflags |= X86_EFLAGS_CF;
+        reg->ds = ds();
+        reg->es = ds();
+        reg->fs = fs();
+        reg->gs = gs();
+}
diff --git a/arch/x86/boot/setup.ld b/arch/x86/boot/setup.ld
index bb8dc2de7969..0f6ec455a2b1 100644
--- a/arch/x86/boot/setup.ld
+++ b/arch/x86/boot/setup.ld
@@ -15,8 +15,11 @@ SECTIONS
 
         . = 497;
         .header         : { *(.header) }
+        .entrytext      : { *(.entrytext) }
         .inittext       : { *(.inittext) }
         .initdata       : { *(.initdata) }
+        __end_init = .;
+
         .text           : { *(.text) }
         .text32         : { *(.text32) }
 
@@ -52,4 +55,7 @@ SECTIONS
 
         . = ASSERT(_end <= 0x8000, "Setup too big!");
         . = ASSERT(hdr == 0x1f1, "The setup header has the wrong offset!");
+        /* Necessary for the very-old-loader check to work... */
+        . = ASSERT(__end_init <= 5*512, "init sections too big!");
+
 }