linux/arch/x86/boot/main.c
Vivek Goyal c041b5ad86 x86, boot: Create a separate string.h file to provide standard string functions
Create a separate arch/x86/boot/string.h file to provide declaration of
some of the common string functions.

By default memcpy, memset and memcmp functions will default to gcc
builtin functions. If code wants to use an optimized version of any
of these functions, they need to #undef the respective macro and link
against a local file providing definition of undefed function.

For example, arch/x86/boot/* code links against copy.S to get memcpy()
and memcmp() definitions. arch/86/boot/compressed/* links against
compressed/string.c.

There are quite a few places in arch/x86/ where these functions are
used. Idea is to try to consilidate  their declaration and possibly
definitions so that it can be reused.

I am planning to reuse boot/string.h in arch/x86/purgatory/ and use
gcc builtin functions for memcpy, memset and memcmp.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Link: http://lkml.kernel.org/r/1395170800-11059-3-git-send-email-vgoyal@redhat.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2014-03-19 15:43:45 -07:00

186 lines
4.3 KiB
C

/* -*- linux-c -*- ------------------------------------------------------- *
*
* 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.
*
* ----------------------------------------------------------------------- */
/*
* Main module for the real-mode kernel code
*/
#include "boot.h"
#include "string.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.
*/
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;
}
}
/*
* Query the keyboard lock status as given by the BIOS, and
* set the keyboard repeat rate to maximum. Unclear why the latter
* is done here; this might be possible to kill off as stale code.
*/
static void keyboard_init(void)
{
struct biosregs ireg, oreg;
initregs(&ireg);
ireg.ah = 0x02; /* Get keyboard status */
intcall(0x16, &ireg, &oreg);
boot_params.kbd_status = oreg.al;
ireg.ax = 0x0305; /* Set keyboard repeat rate */
intcall(0x16, &ireg, NULL);
}
/*
* Get Intel SpeedStep (IST) information.
*/
static void query_ist(void)
{
struct biosregs ireg, oreg;
/* Some older BIOSes apparently crash on this call, so filter
it from machines too old to have SpeedStep at all. */
if (cpu.level < 6)
return;
initregs(&ireg);
ireg.ax = 0xe980; /* IST Support */
ireg.edx = 0x47534943; /* Request value */
intcall(0x15, &ireg, &oreg);
boot_params.ist_info.signature = oreg.eax;
boot_params.ist_info.command = oreg.ebx;
boot_params.ist_info.event = oreg.ecx;
boot_params.ist_info.perf_level = oreg.edx;
}
/*
* Tell the BIOS what CPU mode we intend to run in.
*/
static void set_bios_mode(void)
{
#ifdef CONFIG_X86_64
struct biosregs ireg;
initregs(&ireg);
ireg.ax = 0xec00;
ireg.bx = 2;
intcall(0x15, &ireg, NULL);
#endif
}
static void init_heap(void)
{
char *stack_end;
if (boot_params.hdr.loadflags & CAN_USE_HEAP) {
asm("leal %P1(%%esp),%0"
: "=r" (stack_end) : "i" (-STACK_SIZE));
heap_end = (char *)
((size_t)boot_params.hdr.heap_end_ptr + 0x200);
if (heap_end > stack_end)
heap_end = stack_end;
} else {
/* Boot protocol 2.00 only, no heap available */
puts("WARNING: Ancient bootloader, some functionality "
"may be limited!\n");
}
}
void main(void)
{
/* First, copy the boot header into the "zeropage" */
copy_boot_params();
/* Initialize the early-boot console */
console_init();
if (cmdline_find_option_bool("debug"))
puts("early console in setup code\n");
/* End of heap check */
init_heap();
/* 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?) and query the lock flags */
keyboard_init();
/* Query MCA information */
query_mca();
/* Query Intel SpeedStep (IST) information */
query_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
/* Set the video mode */
set_video();
/* Do the last things and invoke protected mode */
go_to_protected_mode();
}