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Commit 5a18c92a authored by Eric W. Biederman's avatar Eric W. Biederman Committed by Linus Torvalds
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Revert "[PATCH] paravirt: Add startup infrastructure for paravirtualization" 



This reverts commit c9ccf30d.

Entering the kernel at startup_32 without passing our real mode data in
%esi, and without guaranteeing that physical and virtual addresses are
identity mapped makes head.S impossible to maintain.

The only user of this infrastructure is lguest which is not merged so
nothing we currently support will break by removing this over designed
nightmare, and only the pending lguest patches will be affected.  The
pending Xen patches have a different entry point that they use.

We are currently discussing what Xen and lguest need to do to boot the
kernel in a more normal fashion so using startup_32 in this weird manner is
clearly not their long term direction.

So let's remove this code in head.S before it causes brain damage to people
trying to maintain head.S

Cc: Chris Wright <chrisw@sous-sol.org>
Cc: Andi Kleen <ak@suse.de>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Zachary Amsden <zach@vmware.com>
CC: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: default avatarEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 0cfe61e1

arch/i386/kernel/head.S

+0 −38
Original line number Diff line number Diff line
@@ -71,12 +71,6 @@ INIT_MAP_BEYOND_END = BOOTBITMAP_SIZE + (PAGE_TABLE_SIZE + ALLOCATOR_SLOP)*PAGE_ 
.section .text.head,"ax",@progbits

ENTRY(startup_32)



#ifdef CONFIG_PARAVIRT

        movl %cs, %eax

        testl $0x3, %eax

        jnz startup_paravirt

#endif



/*

 * Set segments to known values.

 */
@@ -501,38 +495,6 @@ ignore_int: 
	iret



.section .text

#ifdef CONFIG_PARAVIRT

startup_paravirt:

	cld

 	movl $(init_thread_union+THREAD_SIZE),%esp



	/* We take pains to preserve all the regs. */

	pushl	%edx

	pushl	%ecx

	pushl	%eax



	pushl	$__start_paravirtprobe

1:

	movl	0(%esp), %eax

	cmpl	$__stop_paravirtprobe, %eax

	je	unhandled_paravirt

	pushl	(%eax)

	movl	8(%esp), %eax

	call	*(%esp)

	popl	%eax



	movl	4(%esp), %eax

	movl	8(%esp), %ecx

	movl	12(%esp), %edx



	addl	$4, (%esp)

	jmp	1b



unhandled_paravirt:

	/* Nothing wanted us: we're screwed. */

	ud2

#endif



/*

 * Real beginning of normal "text" segment

 */

arch/i386/kernel/paravirt.c

+0 −1
Original line number Diff line number Diff line
@@ -19,7 +19,6 @@ 
#include <linux/module.h>

#include <linux/efi.h>

#include <linux/bcd.h>

#include <linux/start_kernel.h>

#include <linux/highmem.h>



#include <asm/bug.h>

arch/i386/kernel/vmlinux.lds.S

+0 −6
Original line number Diff line number Diff line
@@ -78,12 +78,6 @@ SECTIONS 
	CONSTRUCTORS

	} :data



  .paravirtprobe : AT(ADDR(.paravirtprobe) - LOAD_OFFSET) {

  	__start_paravirtprobe = .;

	*(.paravirtprobe)

  	__stop_paravirtprobe = .;

  }



  . = ALIGN(4096);

  .data_nosave : AT(ADDR(.data_nosave) - LOAD_OFFSET) {

  	__nosave_begin = .;

include/asm-i386/paravirt.h

+0 −5
Original line number Diff line number Diff line
@@ -222,11 +222,6 @@ struct paravirt_ops 
	void (*iret)(void);

};



/* Mark a paravirt probe function. */

#define paravirt_probe(fn)						\

 static asmlinkage void (*__paravirtprobe_##fn)(void) __attribute_used__ \

		__attribute__((__section__(".paravirtprobe"))) = fn



extern struct paravirt_ops paravirt_ops;



#define PARAVIRT_PATCH(x)					\