Commit c9ccf30d authored by Rusty Russell's avatar Rusty Russell Committed by Andi Kleen
Browse files

[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: default avatarRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: default avatarChris Wright <chrisw@sous-sol.org>
Signed-off-by: default avatarAndi Kleen <ak@suse.de>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Zachary Amsden <zach@vmware.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
parent d7cd5611
......@@ -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
......
......@@ -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
*/
......
......@@ -19,6 +19,7 @@
#include <linux/module.h>
#include <linux/efi.h>
#include <linux/bcd.h>
#include <linux/start_kernel.h>
#include <asm/bug.h>
#include <asm/paravirt.h>
......@@ -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,
......
......@@ -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 = .;
......
......@@ -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)
......
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