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 <>
Cc: Andi Kleen <>
Cc: Jeremy Fitzhardinge <>
Cc: Zachary Amsden <>
CC: H. Peter Anvin <>
Signed-off-by: default avatarEric W. Biederman <>
Signed-off-by: default avatarRusty Russell <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent 0cfe61e1
.section .text.head,"ax",@progbits
movl %cs, %eax
testl $0x3, %eax
jnz startup_paravirt
* Set segments to known values.
......@@ -501,38 +495,6 @@ ignore_int:
.section .text
movl $(init_thread_union+THREAD_SIZE),%esp
/* We take pains to preserve all the regs. */
pushl %edx
pushl %ecx
pushl %eax
pushl $__start_paravirtprobe
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
/* Nothing wanted us: we're screwed. */
* Real beginning of normal "text" segment
......@@ -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>
......@@ -78,12 +78,6 @@ SECTIONS
} :data
.paravirtprobe : AT(ADDR(.paravirtprobe) - LOAD_OFFSET) {
__start_paravirtprobe = .;
__stop_paravirtprobe = .;
. = ALIGN(4096);
.data_nosave : AT(ADDR(.data_nosave) - LOAD_OFFSET) {
__nosave_begin = .;
......@@ -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) \
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