Assembly header and main routine for new x86 setup code

The assembly header and initialization code, and the main() routine.
main.c also contains some miscellaneous very short routines.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 161 insertions, 0 deletions

diff --git a/arch/i386/boot/main.c b/arch/i386/boot/main.c
new file mode 100644
index 000000000000..7f01f96c4fb8
--- /dev/null
+++ b/arch/i386/boot/main.c
@@ -0,0 +1,161 @@
+/* -*- linux-c -*- ------------------------------------------------------- *
+ *
+ *   Copyright (C) 1991, 1992 Linus Torvalds
+ *   Copyright 2007 rPath, Inc. - All Rights Reserved
+ *
+ *   This file is part of the Linux kernel, and is made available under
+ *   the terms of the GNU General Public License version 2.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * arch/i386/boot/main.c
+ *
+ * Main module for the real-mode kernel code
+ */
+
+#include "boot.h"
+
+struct boot_params boot_params __attribute__((aligned(16)));
+
+char *HEAP = _end;
+char *heap_end = _end;          /* Default end of heap = no heap */
+
+/*
+ * Copy the header into the boot parameter block.  Since this
+ * screws up the old-style command line protocol, adjust by
+ * filling in the new-style command line pointer instead.
+ */
+#define OLD_CL_MAGIC    0xA33F
+#define OLD_CL_ADDRESS  0x20
+
+static void copy_boot_params(void)
+{
+        struct old_cmdline {
+                u16 cl_magic;
+                u16 cl_offset;
+        };
+        const struct old_cmdline * const oldcmd =
+                (const struct old_cmdline *)OLD_CL_ADDRESS;
+
+        BUILD_BUG_ON(sizeof boot_params != 4096);
+        memcpy(&boot_params.hdr, &hdr, sizeof hdr);
+
+        if (!boot_params.hdr.cmd_line_ptr &&
+            oldcmd->cl_magic == OLD_CL_MAGIC) {
+                /* Old-style command line protocol. */
+                u16 cmdline_seg;
+
+                /* Figure out if the command line falls in the region
+                   of memory that an old kernel would have copied up
+                   to 0x90000... */
+                if (oldcmd->cl_offset < boot_params.hdr.setup_move_size)
+                        cmdline_seg = ds();
+                else
+                        cmdline_seg = 0x9000;
+
+                boot_params.hdr.cmd_line_ptr =
+                        (cmdline_seg << 4) + oldcmd->cl_offset;
+        }
+}
+
+/*
+ * Set the keyboard repeat rate to maximum.  Unclear why this
+ * is done here; this might be possible to kill off as stale code.
+ */
+static void keyboard_set_repeat(void)
+{
+        u16 ax = 0x0305;
+        u16 bx = 0;
+        asm volatile("int $0x16"
+                     : "+a" (ax), "+b" (bx)
+                     : : "ecx", "edx", "esi", "edi");
+}
+
+/*
+ * Get Intel SpeedStep IST information.
+ */
+static void query_speedstep_ist(void)
+{
+        asm("int $0x15"
+            : "=a" (boot_params.speedstep_info[0]),
+              "=b" (boot_params.speedstep_info[1]),
+              "=c" (boot_params.speedstep_info[2]),
+              "=d" (boot_params.speedstep_info[3])
+            : "a" (0x0000e980),  /* IST Support */
+              "d" (0x47534943)); /* Request value */
+}
+
+/*
+ * Tell the BIOS what CPU mode we intend to run in.
+ */
+static void set_bios_mode(void)
+{
+#ifdef CONFIG_X86_64
+        u32 eax, ebx;
+
+        eax = 0xec00;
+        ebx = 2;
+        asm volatile("int $0x15"
+                     : "+a" (eax), "+b" (ebx)
+                     : : "ecx", "edx", "esi", "edi");
+#endif
+}
+
+void main(void)
+{
+        /* First, copy the boot header into the "zeropage" */
+        copy_boot_params();
+
+        /* End of heap check */
+        if (boot_params.hdr.loadflags & CAN_USE_HEAP) {
+                heap_end = (char *)(boot_params.hdr.heap_end_ptr
+                                    +0x200-STACK_SIZE);
+        } else {
+                /* Boot protocol 2.00 only, no heap available */
+                puts("WARNING: Ancient bootloader, some functionality "
+                     "may be limited!\n");
+        }
+
+        /* Make sure we have all the proper CPU support */
+        if (validate_cpu()) {
+                puts("Unable to boot - please use a kernel appropriate "
+                     "for your CPU.\n");
+                die();
+        }
+
+        /* Tell the BIOS what CPU mode we intend to run in. */
+        set_bios_mode();
+
+        /* Detect memory layout */
+        detect_memory();
+
+        /* Set keyboard repeat rate (why?) */
+        keyboard_set_repeat();
+
+        /* Set the video mode */
+        set_video();
+
+        /* Query MCA information */
+        query_mca();
+
+        /* Voyager */
+#ifdef CONFIG_X86_VOYAGER
+        query_voyager();
+#endif
+
+        /* Query SpeedStep IST information */
+        query_speedstep_ist();
+
+        /* Query APM information */
+#if defined(CONFIG_APM) || defined(CONFIG_APM_MODULE)
+        query_apm_bios();
+#endif
+
+        /* Query EDD information */
+#if defined(CONFIG_EDD) || defined(CONFIG_EDD_MODULE)
+        query_edd();
+#endif
+        /* Do the last things and invoke protected mode */
+        go_to_protected_mode();
+}