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linux/arch/x86/boot/bioscall.S

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x86, setup: "glove box" BIOS calls -- infrastructure Impact: new interfaces (not yet used) For all the platforms out there, there is an infinite number of buggy BIOSes. This adds infrastructure to treat BIOS interrupts more like toxic waste and "glove box" them -- we switch out the register set, perform the BIOS interrupt, and then restore the previous state. LKML-Reference: <49DE7F79.4030106@zytor.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: Rafael J. Wysocki <rjw@sisk.pl>
2009-04-02 05:08:28 +04:00
/* -----------------------------------------------------------------------
*
x86, boot: Move intcall() to the .inittext section The .inittext section tries to aggregate all functions which are needed to get a message out in the case of a load failure. However, putchar() uses intcall(), so intcall() should be in the .inittext section. Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Link: http://lkml.kernel.org/n/tip-twxm8igouzbmsklmf6lfyq0w@git.kernel.org
2014-01-05 02:29:08 +04:00
* Copyright 2009-2014 Intel Corporation; author H. Peter Anvin
x86, setup: "glove box" BIOS calls -- infrastructure Impact: new interfaces (not yet used) For all the platforms out there, there is an infinite number of buggy BIOSes. This adds infrastructure to treat BIOS interrupts more like toxic waste and "glove box" them -- we switch out the register set, perform the BIOS interrupt, and then restore the previous state. LKML-Reference: <49DE7F79.4030106@zytor.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: Rafael J. Wysocki <rjw@sisk.pl>
2009-04-02 05:08:28 +04:00
*
* 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
x86, setup: fix comment in the "glove box" code Impact: Comment change only The glove box is about avoiding problems with *registers* being touched, not *memory*. Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-04-12 09:24:05 +04:00
* touching registers they shouldn't be.
x86, setup: "glove box" BIOS calls -- infrastructure Impact: new interfaces (not yet used) For all the platforms out there, there is an infinite number of buggy BIOSes. This adds infrastructure to treat BIOS interrupts more like toxic waste and "glove box" them -- we switch out the register set, perform the BIOS interrupt, and then restore the previous state. LKML-Reference: <49DE7F79.4030106@zytor.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: Rafael J. Wysocki <rjw@sisk.pl>
2009-04-02 05:08:28 +04:00
*/
x86, boot: Use .code16 instead of .code16gcc This reverts commit 28b48688 ("x86, boot: use .code16gcc instead of .code16"). Versions of binutils older than 2.16 are already not working, so this workaround is no longer necessary either. At the same time, some of the transformations that .code16gcc does can be *extremely* counterintuitive to a human programmer. [ hpa: folded ret -> retl and call -> calll fixes from followup patch ] Signed-off-by: David Woodhouse <David.Woodhouse@intel.com> Link: http://lkml.kernel.org/r/1388788242.2391.75.camel@shinybook.infradead.org Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2014-01-04 02:30:42 +04:00
.code16
x86, boot: Move intcall() to the .inittext section The .inittext section tries to aggregate all functions which are needed to get a message out in the case of a load failure. However, putchar() uses intcall(), so intcall() should be in the .inittext section. Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Link: http://lkml.kernel.org/n/tip-twxm8igouzbmsklmf6lfyq0w@git.kernel.org
2014-01-05 02:29:08 +04:00
.section ".inittext","ax"
x86, setup: "glove box" BIOS calls -- infrastructure Impact: new interfaces (not yet used) For all the platforms out there, there is an infinite number of buggy BIOSes. This adds infrastructure to treat BIOS interrupts more like toxic waste and "glove box" them -- we switch out the register set, perform the BIOS interrupt, and then restore the previous state. LKML-Reference: <49DE7F79.4030106@zytor.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: Rafael J. Wysocki <rjw@sisk.pl>
2009-04-02 05:08:28 +04:00
.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
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