Messages in this thread Patch in this message | | | Subject | [PATCH 1/10] lguest: Don't rely on last-linked fallthru when no paravirt handler | From | Rusty Russell <> | Date | Fri, 09 Feb 2007 20:14:18 +1100 |
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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@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",
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