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 and it's linked last.
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.
This implements a real fallthrough if we pass all the registered
paravirt probes.
Signed-off-by: Rusty Russell <rusty at rustcorp.com.au>
===================================================================
--- a/arch/i386/kernel/Makefile
+++ b/arch/i386/kernel/Makefile
@@ -39,8 +39,6 @@ obj-$(CONFIG_EARLY_PRINTK) += early_prin
obj-$(CONFIG_EARLY_PRINTK) += early_printk.o
obj-$(CONFIG_HPET_TIMER) += hpet.o
obj-$(CONFIG_K8_NB) += k8.o
-
-# Make sure this is linked after any other paravirt_ops structs: see head.S
obj-$(CONFIG_PARAVIRT) += paravirt.o
EXTRA_AFLAGS := -traditional
===================================================================
--- a/arch/i386/kernel/head.S
+++ b/arch/i386/kernel/head.S
@@ -502,10 +502,11 @@ 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)
@@ -517,6 +518,12 @@ 1:
addl $4, (%esp)
jmp 1b
+
+unhandled_paravirt:
+ /* Nothing wanted us: try to die with dignity (impossible trap). */
+ movl $0x1F, %edx
+ pushl $0
+ jmp early_fault
#endif
/*
===================================================================
--- a/arch/i386/kernel/paravirt.c
+++ b/arch/i386/kernel/paravirt.c
@@ -481,9 +481,6 @@ static int __init print_banner(void)
return 0;
}
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",
