Revert "[PATCH] paravirt: Add startup infrastructure for paravirtualization"

This reverts commit c9ccf30d77f04064fe5436027ab9d2230c7cdd94.

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: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 0 insertions, 45 deletions

diff --git a/arch/i386/kernel/head.S b/arch/i386/kernel/head.S
index 9b10af65faaa..f74dfc419b56 100644
--- a/arch/i386/kernel/head.S
+++ b/arch/i386/kernel/head.S
@@ -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
  */
diff --git a/arch/i386/kernel/paravirt.c b/arch/i386/kernel/paravirt.c
index 5c10f376bce1..faab09abca5e 100644
--- a/arch/i386/kernel/paravirt.c
+++ b/arch/i386/kernel/paravirt.c
@@ -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>
diff --git a/arch/i386/kernel/vmlinux.lds.S b/arch/i386/kernel/vmlinux.lds.S
index 23e8614edeee..80bec6640230 100644
--- a/arch/i386/kernel/vmlinux.lds.S
+++ b/arch/i386/kernel/vmlinux.lds.S
@@ -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 = .;