path: root/arch/x86/kernel/vmi_32.c

/*
 * VMI specific paravirt-ops implementation
 *
 * Copyright (C) 2005, VMware, Inc.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
 * NON INFRINGEMENT.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * Send feedback to zach@vmware.com
 *
 */

#include <linux/module.h>
#include <linux/cpu.h>
#include <linux/bootmem.h>
#include <linux/mm.h>
#include <linux/highmem.h>
#include <linux/sched.h>
#include <asm/vmi.h>
#include <asm/io.h>
#include <asm/fixmap.h>
#include <asm/apicdef.h>
#include <asm/apic.h>
#include <asm/processor.h>
#include <asm/timer.h>
#include <asm/vmi_time.h>
#include <asm/kmap_types.h>
#include <asm/setup.h>

/* Convenient for calling VMI functions indirectly in the ROM */
typedef u32 __attribute__((regparm(1))) (VROMFUNC)(void);
typedef u64 __attribute__((regparm(2))) (VROMLONGFUNC)(int);

#define call_vrom_func(rom,func) \
   (((VROMFUNC *)(rom->func))())

#define call_vrom_long_func(rom,func,arg) \
   (((VROMLONGFUNC *)(rom->func)) (arg))

static struct vrom_header *vmi_rom;
static int disable_pge;
static int disable_pse;
static int disable_sep;
static int disable_tsc;
static int disable_mtrr;
static int disable_noidle;
static int disable_vmi_timer;

/* Cached VMI operations */
static struct {
	void (*cpuid)(void /* non-c */);
	void (*_set_ldt)(u32 selector);
	void (*set_tr)(u32 selector);
	void (*write_idt_entry)(struct desc_struct *, int, u32, u32);
	void (*write_gdt_entry)(struct desc_struct *, int, u32, u32);
	void (*write_ldt_entry)(struct desc_struct *, int, u32, u32);
	void (*set_kernel_stack)(u32 selector, u32 sp0);
	void (*allocate_page)(u32, u32, u32, u32, u32);
	void (*release_page)(u32, u32);
	void (*set_pte)(pte_t, pte_t *, unsigned);
	void (*update_pte)(pte_t *, unsigned);
	void (*set_linear_mapping)(int, void *, u32, u32);
	void (*_flush_tlb)(int);
	void (*set_initial_ap_state)(int, int);
	void (*halt)(void);
  	void (*set_lazy_mode)(int mode);
} vmi_ops;

/* Cached VMI operations */
struct vmi_timer_ops vmi_timer_ops;

/*
 * VMI patching routines.
 */
#define MNEM_CALL 0xe8
#define MNEM_JMP  0xe9
#define MNEM_RET  0xc3

#define IRQ_PATCH_INT_MASK 0
#define IRQ_PATCH_DISABLE  5

static inline void patch_offset(void *insnbuf,
				unsigned long ip, unsigned long dest)
{
        *(unsigned long *)(insnbuf+1) = dest-ip-5;
}

static unsigned patch_internal(int call, unsigned len, void *insnbuf,
			       unsigned long ip)
{
	u64 reloc;
	struct vmi_relocation_info *const rel = (struct vmi_relocation_info *)&reloc;
	reloc = call_vrom_long_func(vmi_rom, get_reloc,	call);
	switch(rel->type) {
		case VMI_RELOCATION_CALL_REL:
			BUG_ON(len < 5);
			*(char *)insnbuf = MNEM_CALL;
			patch_offset(insnbuf, ip, (unsigned long)rel->eip);
			return 5;

		case VMI_RELOCATION_JUMP_REL:
			BUG_ON(len < 5);
			*(char *)insnbuf = MNEM_JMP;
			patch_offset(insnbuf, ip, (unsigned long)rel->eip);
			return 5;

		case VMI_RELOCATION_NOP:
			/* obliterate the whole thing */
			return 0;

		case VMI_RELOCATION_NONE:
			/* leave native code in place */
			break;

		default:
			BUG();
	}
	return len;
}

/*
 * Apply patch if appropriate, return length of new instruction
 * sequence.  The callee does nop padding for us.
 */
static unsigned vmi_patch(u8 type, u16 clobbers, void *insns,
			  unsigned long ip, unsigned len)
{
	switch (type) {
		case PARAVIRT_PATCH(pv_irq_ops.irq_disable):
			return patch_internal(VMI_CALL_DisableInterrupts, len,
					      insns, ip);
		case PARAVIRT_PATCH(pv_irq_ops.irq_enable):
			return patch_internal(VMI_CALL_EnableInterrupts, len,
					      insns, ip);