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[PATCH] i386: paravirt unhandled fallthrough

The current code simply calls "start_kernel" directly if we're under a
hypervisor and no paravirt_ops backend wants us, because paravirt.c
registers that as a backend.

This was always a vain hope; start_kernel won't get far without setup.
It's also impossible for paravirt_ops backends which don't sit in the
arch/i386/kernel directory: they can't link before paravirt.o anyway.

Keep it simple: if we pass all the registered paravirt probes, BUG().

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andi Kleen <ak@suse.de>
Rusty Russell 18 年 前
コミット
992af68147
3 ファイル変更6 行追加6 行削除
  1. 0 2
      arch/i386/kernel/Makefile
  2. 6 1
      arch/i386/kernel/head.S
  3. 0 3
      arch/i386/kernel/paravirt.c

+ 0 - 2
arch/i386/kernel/Makefile

@@ -41,8 +41,6 @@ obj-$(CONFIG_HPET_TIMER) 	+= hpet.o
 obj-$(CONFIG_K8_NB)		+= k8.o
 
 obj-$(CONFIG_VMI)		+= vmi.o vmitime.o
-
-# Make sure this is linked after any other paravirt_ops structs: see head.S
 obj-$(CONFIG_PARAVIRT)		+= paravirt.o
 
 EXTRA_AFLAGS   := -traditional

+ 6 - 1
arch/i386/kernel/head.S

@@ -513,10 +513,11 @@ startup_paravirt:
 	pushl	%ecx
 	pushl	%eax
 
-	/* paravirt.o is last in link, and that probe fn never returns */
 	pushl	$__start_paravirtprobe
 1:
 	movl	0(%esp), %eax
+	cmpl	$__stop_paravirtprobe, %eax
+	je	unhandled_paravirt
 	pushl	(%eax)
 	movl	8(%esp), %eax
 	call	*(%esp)
@@ -528,6 +529,10 @@ startup_paravirt:
 
 	addl	$4, (%esp)
 	jmp	1b
+
+unhandled_paravirt:
+	/* Nothing wanted us: we're screwed. */
+	ud2
 #endif
 
 /*

+ 0 - 3
arch/i386/kernel/paravirt.c

@@ -482,9 +482,6 @@ static int __init print_banner(void)
 }
 core_initcall(print_banner);
 
-/* We simply declare start_kernel to be the paravirt probe of last resort. */
-paravirt_probe(start_kernel);
-
 struct paravirt_ops paravirt_ops = {
 	.name = "bare hardware",
 	.paravirt_enabled = 0,