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Commit df7699c5 authored by H. Peter Anvin's avatar H. Peter Anvin Committed by H. Peter Anvin
Browse files

x86, setup: "glove box" BIOS interrupts in the core boot code 



Impact: BIOS proofing

"Glove box" off BIOS interrupts in the core boot code.

LKML-Reference: <49DE7F79.4030106@zytor.com>
Signed-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
parent 7a734e7d

arch/x86/boot/a20.c

+6 −3
Original line number Diff line number Diff line
@@ -2,7 +2,7 @@ 
 *

 *   Copyright (C) 1991, 1992 Linus Torvalds

 *   Copyright 2007-2008 rPath, Inc. - All Rights Reserved

 *   Copyright 2009 Intel Corporation

 *   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.
@@ -90,8 +90,11 @@ static int a20_test_long(void) 


static void enable_a20_bios(void)

{

	asm volatile("pushfl; int $0x15; popfl"

		     : : "a" ((u16)0x2401));

	struct biosregs ireg;



	initregs(&ireg);

	ireg.ax = 0x2401;

	intcall(0x15, &ireg, NULL);

}



static void enable_a20_kbc(void)

arch/x86/boot/main.c

+21 −18
Original line number Diff line number Diff line
@@ -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.
@@ -61,11 +62,10 @@ static void copy_boot_params(void) 
 */

static void keyboard_set_repeat(void)

{

	u16 ax = 0x0305;

	u16 bx = 0;

	asm volatile("int $0x16"

		     : "+a" (ax), "+b" (bx)

		     : : "ecx", "edx", "esi", "edi");

	struct biosregs ireg;

	initregs(&ireg);

	ireg.ax = 0x0305;

	intcall(0x16, &ireg, NULL);

}



/*
@@ -73,18 +73,22 @@ static void keyboard_set_repeat(void) 
 */

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;



	asm("int $0x15"

	    : "=a" (boot_params.ist_info.signature),

	      "=b" (boot_params.ist_info.command),

	      "=c" (boot_params.ist_info.event),

	      "=d" (boot_params.ist_info.perf_level)

	    : "a" (0x0000e980),	 /* IST Support */

	      "d" (0x47534943)); /* Request value */

	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;

}



/*
@@ -93,13 +97,12 @@ static void query_ist(void) 
static void set_bios_mode(void)

{

#ifdef CONFIG_X86_64

	u32 eax, ebx;

	struct biosregs ireg;



	eax = 0xec00;

	ebx = 2;

	asm volatile("int $0x15"

		     : "+a" (eax), "+b" (ebx)

		     : : "ecx", "edx", "esi", "edi");

	initregs(&ireg);

	ireg.ax = 0xec00;

	ireg.bx = 2;

	intcall(0x15, &ireg, NULL);

#endif

}

arch/x86/boot/memory.c

+40 −41
Original line number Diff line number Diff line
@@ -25,12 +25,16 @@ struct e820_ext_entry { 
static int detect_memory_e820(void)

{

	int count = 0;

	u32 next = 0;

	u32 size, id, edi;

	u8 err;

	struct biosregs ireg, oreg;

	struct e820entry *desc = boot_params.e820_map;

	static struct e820_ext_entry buf; /* static so it is zeroed */



	initregs(&ireg);

	ireg.ax  = 0xe820;

	ireg.cx  = sizeof buf;

	ireg.edx = SMAP;

	ireg.di  = (size_t)&buf;



	/*

	 * Set this here so that if the BIOS doesn't change this field

	 * but still doesn't change %ecx, we're still okay...
@@ -38,22 +42,13 @@ static int detect_memory_e820(void) 
	buf.ext_flags = 1;



	do {

		size = sizeof buf;



		/* Important: %edx and %esi are clobbered by some BIOSes,

		   so they must be either used for the error output

		   or explicitly marked clobbered.  Given that, assume there

		   is something out there clobbering %ebp and %edi, too. */

		asm("pushl %%ebp; int $0x15; popl %%ebp; setc %0"

		    : "=d" (err), "+b" (next), "=a" (id), "+c" (size),

		      "=D" (edi), "+m" (buf)

		    : "D" (&buf), "d" (SMAP), "a" (0xe820)

		    : "esi");

		intcall(0x15, &ireg, &oreg);

		ireg.ebx = oreg.ebx; /* for next iteration... */



		/* BIOSes which terminate the chain with CF = 1 as opposed

		   to %ebx = 0 don't always report the SMAP signature on

		   the final, failing, probe. */

		if (err)

		if (oreg.eflags & X86_EFLAGS_CF)

			break;



		/* Some BIOSes stop returning SMAP in the middle of
@@ -61,7 +56,7 @@ static int detect_memory_e820(void) 
		   screwed up the map at that point, we might have a

		   partial map, the full map, or complete garbage, so

		   just return failure. */

		if (id != SMAP) {

		if (oreg.eax != SMAP) {

			count = 0;

			break;

		}
@@ -69,58 +64,62 @@ static int detect_memory_e820(void) 
		/* ACPI 3.0 added the extended flags support.  If bit 0

		   in the extended flags is zero, we're supposed to simply

		   ignore the entry -- a backwards incompatible change! */

		if (size > 20 && !(buf.ext_flags & 1))

		if (oreg.cx > 20 && !(buf.ext_flags & 1))

			continue;



		*desc++ = buf.std;

		count++;

	} while (next && count < ARRAY_SIZE(boot_params.e820_map));

	} while (ireg.ebx && count < ARRAY_SIZE(boot_params.e820_map));



	return boot_params.e820_entries = count;

}



static int detect_memory_e801(void)

{

	u16 ax, bx, cx, dx;

	u8 err;

	struct biosregs ireg, oreg;



	bx = cx = dx = 0;

	ax = 0xe801;

	asm("stc; int $0x15; setc %0"

	    : "=m" (err), "+a" (ax), "+b" (bx), "+c" (cx), "+d" (dx));

	initregs(&ireg);

	ireg.ax = 0xe801;

	intcall(0x15, &ireg, &oreg);



	if (err)

	if (oreg.eflags & X86_EFLAGS_CF)

		return -1;



	/* Do we really need to do this? */

	if (cx || dx) {

		ax = cx;

		bx = dx;

	if (oreg.cx || oreg.dx) {

		oreg.ax = oreg.cx;

		oreg.bx = oreg.dx;

	}



	if (ax > 15*1024)

	if (oreg.ax > 15*1024) {

		return -1;	/* Bogus! */



	/* This ignores memory above 16MB if we have a memory hole

	   there.  If someone actually finds a machine with a memory

	   hole at 16MB and no support for 0E820h they should probably

	   generate a fake e820 map. */

	boot_params.alt_mem_k = (ax == 15*1024) ? (dx << 6)+ax : ax;

	} else if (oreg.ax == 15*1024) {

		boot_params.alt_mem_k = (oreg.dx << 6) + oreg.ax;

	} else {

		/*

		 * This ignores memory above 16MB if we have a memory

		 * hole there.  If someone actually finds a machine

		 * with a memory hole at 16MB and no support for

		 * 0E820h they should probably generate a fake e820

		 * map.

		 */

		boot_params.alt_mem_k = oreg.ax;

	}



	return 0;

}



static int detect_memory_88(void)

{

	u16 ax;

	u8 err;

	struct biosregs ireg, oreg;



	ax = 0x8800;

	asm("stc; int $0x15; setc %0" : "=bcdm" (err), "+a" (ax));

	initregs(&ireg);

	ireg.ah = 0x88;

	intcall(0x15, &ireg, &oreg);



	boot_params.screen_info.ext_mem_k = ax;

	boot_params.screen_info.ext_mem_k = oreg.ax;



	return -err;

	return -(oreg.eflags & X86_EFLAGS_CF); /* 0 or -1 */

}



int detect_memory(void)

arch/x86/boot/tty.c

+28 −24
Original line number Diff line number Diff line
@@ -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.
@@ -22,24 +23,23 @@ 


void __attribute__((section(".inittext"))) putchar(int ch)

{

	unsigned char c = ch;

	struct biosregs ireg;



	if (c == '\n')

	if (ch == '\n')

		putchar('\r');	/* \n -> \r\n */



	/* int $0x10 is known to have bugs involving touching registers

	   it shouldn't.  Be extra conservative... */

	asm volatile("pushal; pushw %%ds; int $0x10; popw %%ds; popal"

		     : : "b" (0x0007), "c" (0x0001), "a" (0x0e00|ch));

	initregs(&ireg);

	ireg.bx = 0x0007;

	ireg.cx = 0x0001;

	ireg.ah = 0x0e;

	ireg.al = ch;

	intcall(0x10, &ireg, NULL);

}



void __attribute__((section(".inittext"))) puts(const char *str)

{

	int n = 0;

	while (*str) {

	while (*str)

		putchar(*str++);

		n++;

	}

}



/*
@@ -49,14 +49,13 @@ void __attribute__((section(".inittext"))) puts(const char *str) 


static u8 gettime(void)

{

	u16 ax = 0x0200;

	u16 cx, dx;

	struct biosregs ireg, oreg;



	asm volatile("int $0x1a"

		     : "+a" (ax), "=c" (cx), "=d" (dx)

		     : : "ebx", "esi", "edi");

	initregs(&ireg);

	ireg.ah = 0x02;

	intcall(0x1a, &ireg, &oreg);



	return dx >> 8;

	return oreg.dh;

}



/*
@@ -64,19 +63,24 @@ static u8 gettime(void) 
 */

int getchar(void)

{

	u16 ax = 0;

	asm volatile("int $0x16" : "+a" (ax));

	struct biosregs ireg, oreg;



	initregs(&ireg);

	/* ireg.ah = 0x00; */

	intcall(0x16, &ireg, &oreg);



	return ax & 0xff;

	return oreg.al;

}



static int kbd_pending(void)

{

	u8 pending;

	asm volatile("int $0x16; setnz %0"

		     : "=qm" (pending)

		     : "a" (0x0100));

	return pending;

	struct biosregs ireg, oreg;



	initregs(&ireg);

	ireg.ah = 0x01;

	intcall(0x16, &ireg, &oreg);



	return !(oreg.eflags & X86_EFLAGS_ZF);

}



void kbd_flush(void)