From c9ccf30d77f04064fe5436027ab9d2230c7cdd94 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Thu, 7 Dec 2006 02:14:08 +0100 Subject: [PATCH] [PATCH] paravirt: Add startup infrastructure for paravirtualization 1) Each hypervisor writes a probe function to detect whether we are running under that hypervisor. paravirt_probe() registers this function. 2) If vmlinux is booted with ring != 0, we call all the probe functions (with registers except %esp intact) in link order: the winner will not return. Signed-off-by: Rusty Russell Signed-off-by: Chris Wright Signed-off-by: Andi Kleen Cc: Jeremy Fitzhardinge Cc: Zachary Amsden Signed-off-by: Andrew Morton --- arch/i386/kernel/Makefile | 2 ++ arch/i386/kernel/head.S | 33 +++++++++++++++++++++++++++++++++ arch/i386/kernel/paravirt.c | 4 ++++ arch/i386/kernel/vmlinux.lds.S | 6 ++++++ include/asm-i386/paravirt.h | 5 +++++ 5 files changed, 50 insertions(+) diff --git a/arch/i386/kernel/Makefile b/arch/i386/kernel/Makefile index 406612136049..1e8988e558c5 100644 --- a/arch/i386/kernel/Makefile +++ b/arch/i386/kernel/Makefile @@ -39,6 +39,8 @@ obj-$(CONFIG_VM86) += vm86.o obj-$(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 diff --git a/arch/i386/kernel/head.S b/arch/i386/kernel/head.S index 5b14e95ac8b9..edef5084ce17 100644 --- a/arch/i386/kernel/head.S +++ b/arch/i386/kernel/head.S @@ -55,6 +55,12 @@ */ ENTRY(startup_32) +#ifdef CONFIG_PARAVIRT + movl %cs, %eax + testl $0x3, %eax + jnz startup_paravirt +#endif + /* * Set segments to known values. */ @@ -486,6 +492,33 @@ ignore_int: #endif iret +#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 + + /* paravirt.o is last in link, and that probe fn never returns */ + pushl $__start_paravirtprobe +1: + movl 0(%esp), %eax + 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 +#endif + /* * Real beginning of normal "text" segment */ diff --git a/arch/i386/kernel/paravirt.c b/arch/i386/kernel/paravirt.c index d46460426446..5a9bd3250a1a 100644 --- a/arch/i386/kernel/paravirt.c +++ b/arch/i386/kernel/paravirt.c @@ -19,6 +19,7 @@ #include #include #include +#include #include #include @@ -387,6 +388,9 @@ 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, diff --git a/arch/i386/kernel/vmlinux.lds.S b/arch/i386/kernel/vmlinux.lds.S index 5c69cf0e5944..877dc5cfe3a8 100644 --- a/arch/i386/kernel/vmlinux.lds.S +++ b/arch/i386/kernel/vmlinux.lds.S @@ -65,6 +65,12 @@ SECTIONS CONSTRUCTORS } :data + __start_paravirtprobe = .; + .paravirtprobe : AT(ADDR(.paravirtprobe) - LOAD_OFFSET) { + *(.paravirtprobe) + } + __stop_paravirtprobe = .; + . = ALIGN(4096); .data_nosave : AT(ADDR(.data_nosave) - LOAD_OFFSET) { __nosave_begin = .; diff --git a/include/asm-i386/paravirt.h b/include/asm-i386/paravirt.h index 081194751ade..dd707d8c8270 100644 --- a/include/asm-i386/paravirt.h +++ b/include/asm-i386/paravirt.h @@ -120,6 +120,11 @@ struct paravirt_ops void (fastcall *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_enabled() (paravirt_ops.paravirt_enabled) -- 2.20.1