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linux-sg2042/arch/x86/kernel/paravirt.c

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/* Paravirtualization interfaces
Copyright (C) 2006 Rusty Russell IBM Corporation
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. 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
2007 - x86_64 support added by Glauber de Oliveira Costa, Red Hat Inc
*/
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/export.h>
#include <linux/efi.h>
#include <linux/bcd.h>
#include <linux/highmem.h>
#include <linux/kprobes.h>
#include <asm/bug.h>
#include <asm/paravirt.h>
#include <asm/debugreg.h>
#include <asm/desc.h>
#include <asm/setup.h>
#include <asm/pgtable.h>
#include <asm/time.h>
#include <asm/pgalloc.h>
#include <asm/irq.h>
#include <asm/delay.h>
#include <asm/fixmap.h>
#include <asm/apic.h>
#include <asm/tlbflush.h>
#include <asm/timer.h>
#include <asm/special_insns.h>
/*
* nop stub, which must not clobber anything *including the stack* to
* avoid confusing the entry prologues.
*/
extern void _paravirt_nop(void);
asm (".pushsection .entry.text, \"ax\"\n"
".global _paravirt_nop\n"
"_paravirt_nop:\n\t"
"ret\n\t"
".size _paravirt_nop, . - _paravirt_nop\n\t"
".type _paravirt_nop, @function\n\t"
".popsection");
/* identity function, which can be inlined */
u32 notrace _paravirt_ident_32(u32 x)
{
return x;
}
u64 notrace _paravirt_ident_64(u64 x)
{
return x;
}
void __init default_banner(void)
{
printk(KERN_INFO "Booting paravirtualized kernel on %s\n",
pv_info.name);
}
/* Undefined instruction for dealing with missing ops pointers. */
static const unsigned char ud2a[] = { 0x0f, 0x0b };
struct branch {
unsigned char opcode;
u32 delta;
} __attribute__((packed));
unsigned paravirt_patch_call(void *insnbuf,
const void *target, u16 tgt_clobbers,
unsigned long addr, u16 site_clobbers,
unsigned len)
{
struct branch *b = insnbuf;
unsigned long delta = (unsigned long)target - (addr+5);
if (tgt_clobbers & ~site_clobbers)
return len; /* target would clobber too much for this site */
if (len < 5)
return len; /* call too long for patch site */
b->opcode = 0xe8; /* call */
b->delta = delta;
BUILD_BUG_ON(sizeof(*b) != 5);
return 5;
}
unsigned paravirt_patch_jmp(void *insnbuf, const void *target,
unsigned long addr, unsigned len)
{
struct branch *b = insnbuf;
unsigned long delta = (unsigned long)target - (addr+5);
if (len < 5)
return len; /* call too long for patch site */
b->opcode = 0xe9; /* jmp */
b->delta = delta;
return 5;
}
/* Neat trick to map patch type back to the call within the
* corresponding structure. */
static void *get_call_destination(u8 type)
{
struct paravirt_patch_template tmpl = {
.pv_init_ops = pv_init_ops,
.pv_time_ops = pv_time_ops,
.pv_cpu_ops = pv_cpu_ops,
.pv_irq_ops = pv_irq_ops,
.pv_mmu_ops = pv_mmu_ops,
#ifdef CONFIG_PARAVIRT_SPINLOCKS
.pv_lock_ops = pv_lock_ops,
#endif
};
return *((void **)&tmpl + type);
}
unsigned paravirt_patch_default(u8 type, u16 clobbers, void *insnbuf,
unsigned long addr, unsigned len)
{
void *opfunc = get_call_destination(type);
unsigned ret;
if (opfunc == NULL)
/* If there's no function, patch it with a ud2a (BUG) */
ret = paravirt_patch_insns(insnbuf, len, ud2a, ud2a+sizeof(ud2a));
else if (opfunc == _paravirt_nop)
ret = 0;
/* identity functions just return their single argument */
else if (opfunc == _paravirt_ident_32)
ret = paravirt_patch_ident_32(insnbuf, len);
else if (opfunc == _paravirt_ident_64)
ret = paravirt_patch_ident_64(insnbuf, len);
else if (type == PARAVIRT_PATCH(pv_cpu_ops.iret) ||
type == PARAVIRT_PATCH(pv_cpu_ops.usergs_sysret64))
/* If operation requires a jmp, then jmp */
ret = paravirt_patch_jmp(insnbuf, opfunc, addr, len);
else
/* Otherwise call the function; assume target could
clobber any caller-save reg */
ret = paravirt_patch_call(insnbuf, opfunc, CLBR_ANY,
addr, clobbers, len);
return ret;
}
unsigned paravirt_patch_insns(void *insnbuf, unsigned len,
const char *start, const char *end)
{
unsigned insn_len = end - start;
if (insn_len > len || start == NULL)
insn_len = len;
else
memcpy(insnbuf, start, insn_len);
return insn_len;
}
static void native_flush_tlb(void)
{
__native_flush_tlb();
}
/*
* Global pages have to be flushed a bit differently. Not a real
* performance problem because this does not happen often.
*/
static void native_flush_tlb_global(void)
{
__native_flush_tlb_global();
}
static void native_flush_tlb_single(unsigned long addr)
{
__native_flush_tlb_single(addr);
}
struct static_key paravirt_steal_enabled;
struct static_key paravirt_steal_rq_enabled;
static u64 native_steal_clock(int cpu)
{
return 0;
}
/* These are in entry.S */
extern void native_iret(void);
extern void native_usergs_sysret64(void);
static struct resource reserve_ioports = {
.start = 0,
.end = IO_SPACE_LIMIT,
.name = "paravirt-ioport",
.flags = IORESOURCE_IO | IORESOURCE_BUSY,
};
/*
* Reserve the whole legacy IO space to prevent any legacy drivers
* from wasting time probing for their hardware. This is a fairly
* brute-force approach to disabling all non-virtual drivers.
*
* Note that this must be called very early to have any effect.
*/
int paravirt_disable_iospace(void)
{
return request_resource(&ioport_resource, &reserve_ioports);
}
static DEFINE_PER_CPU(enum paravirt_lazy_mode, paravirt_lazy_mode) = PARAVIRT_LAZY_NONE;
static inline void enter_lazy(enum paravirt_lazy_mode mode)
{
BUG_ON(this_cpu_read(paravirt_lazy_mode) != PARAVIRT_LAZY_NONE);
this_cpu_write(paravirt_lazy_mode, mode);
}
static void leave_lazy(enum paravirt_lazy_mode mode)
{
BUG_ON(this_cpu_read(paravirt_lazy_mode) != mode);
this_cpu_write(paravirt_lazy_mode, PARAVIRT_LAZY_NONE);
}
void paravirt_enter_lazy_mmu(void)
{
enter_lazy(PARAVIRT_LAZY_MMU);
}
void paravirt_leave_lazy_mmu(void)
{
leave_lazy(PARAVIRT_LAZY_MMU);
}
void paravirt_flush_lazy_mmu(void)
{
preempt_disable();
if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU) {
arch_leave_lazy_mmu_mode();
arch_enter_lazy_mmu_mode();
}
preempt_enable();
}
void paravirt_start_context_switch(struct task_struct *prev)
{
BUG_ON(preemptible());
if (this_cpu_read(paravirt_lazy_mode) == PARAVIRT_LAZY_MMU) {
arch_leave_lazy_mmu_mode();
set_ti_thread_flag(task_thread_info(prev), TIF_LAZY_MMU_UPDATES);
}
enter_lazy(PARAVIRT_LAZY_CPU);
}
void paravirt_end_context_switch(struct task_struct *next)
{
BUG_ON(preemptible());
leave_lazy(PARAVIRT_LAZY_CPU);
if (test_and_clear_ti_thread_flag(task_thread_info(next), TIF_LAZY_MMU_UPDATES))
arch_enter_lazy_mmu_mode();
}
enum paravirt_lazy_mode paravirt_get_lazy_mode(void)
{
if (in_interrupt())
return PARAVIRT_LAZY_NONE;
return this_cpu_read(paravirt_lazy_mode);
}
struct pv_info pv_info = {
.name = "bare hardware",
.kernel_rpl = 0,
.shared_kernel_pmd = 1, /* Only used when CONFIG_X86_PAE is set */
#ifdef CONFIG_X86_64
.extra_user_64bit_cs = __USER_CS,
#endif
};
struct pv_init_ops pv_init_ops = {
.patch = native_patch,
};
struct pv_time_ops pv_time_ops = {
.sched_clock = native_sched_clock,
.steal_clock = native_steal_clock,
};
__visible struct pv_irq_ops pv_irq_ops = {
.save_fl = __PV_IS_CALLEE_SAVE(native_save_fl),
.restore_fl = __PV_IS_CALLEE_SAVE(native_restore_fl),
.irq_disable = __PV_IS_CALLEE_SAVE(native_irq_disable),
.irq_enable = __PV_IS_CALLEE_SAVE(native_irq_enable),
.safe_halt = native_safe_halt,
.halt = native_halt,
#ifdef CONFIG_X86_64
.adjust_exception_frame = paravirt_nop,
#endif
};
__visible struct pv_cpu_ops pv_cpu_ops = {
.cpuid = native_cpuid,
.get_debugreg = native_get_debugreg,
.set_debugreg = native_set_debugreg,
.read_cr0 = native_read_cr0,
.write_cr0 = native_write_cr0,
.read_cr4 = native_read_cr4,
.write_cr4 = native_write_cr4,
#ifdef CONFIG_X86_64
.read_cr8 = native_read_cr8,
.write_cr8 = native_write_cr8,
#endif
.wbinvd = native_wbinvd,
.read_msr = native_read_msr,
.write_msr = native_write_msr,
.read_msr_safe = native_read_msr_safe,
.write_msr_safe = native_write_msr_safe,
.read_pmc = native_read_pmc,
.load_tr_desc = native_load_tr_desc,
.set_ldt = native_set_ldt,
.load_gdt = native_load_gdt,
.load_idt = native_load_idt,
.store_idt = native_store_idt,
.store_tr = native_store_tr,
.load_tls = native_load_tls,
#ifdef CONFIG_X86_64
.load_gs_index = native_load_gs_index,
#endif
.write_ldt_entry = native_write_ldt_entry,
.write_gdt_entry = native_write_gdt_entry,
.write_idt_entry = native_write_idt_entry,
.alloc_ldt = paravirt_nop,
.free_ldt = paravirt_nop,
.load_sp0 = native_load_sp0,
#ifdef CONFIG_X86_64
.usergs_sysret64 = native_usergs_sysret64,
#endif
.iret = native_iret,
.swapgs = native_swapgs,
.set_iopl_mask = native_set_iopl_mask,
.io_delay = native_io_delay,
.start_context_switch = paravirt_nop,
.end_context_switch = paravirt_nop,
};
/* At this point, native_get/set_debugreg has real function entries */
NOKPROBE_SYMBOL(native_get_debugreg);
NOKPROBE_SYMBOL(native_set_debugreg);
NOKPROBE_SYMBOL(native_load_idt);
#if defined(CONFIG_X86_32) && !defined(CONFIG_X86_PAE)
/* 32-bit pagetable entries */
#define PTE_IDENT __PV_IS_CALLEE_SAVE(_paravirt_ident_32)
#else
/* 64-bit pagetable entries */
#define PTE_IDENT __PV_IS_CALLEE_SAVE(_paravirt_ident_64)
#endif
struct pv_mmu_ops pv_mmu_ops __ro_after_init = {
.read_cr2 = native_read_cr2,
.write_cr2 = native_write_cr2,
.read_cr3 = native_read_cr3,
.write_cr3 = native_write_cr3,
.flush_tlb_user = native_flush_tlb,
.flush_tlb_kernel = native_flush_tlb_global,
.flush_tlb_single = native_flush_tlb_single,
.flush_tlb_others = native_flush_tlb_others,
.pgd_alloc = __paravirt_pgd_alloc,
.pgd_free = paravirt_nop,
.alloc_pte = paravirt_nop,
.alloc_pmd = paravirt_nop,
.alloc_pud = paravirt_nop,
.alloc_p4d = paravirt_nop,
.release_pte = paravirt_nop,
.release_pmd = paravirt_nop,
.release_pud = paravirt_nop,
.release_p4d = paravirt_nop,
.set_pte = native_set_pte,
.set_pte_at = native_set_pte_at,
.set_pmd = native_set_pmd,
.set_pmd_at = native_set_pmd_at,
.pte_update = paravirt_nop,
.ptep_modify_prot_start = __ptep_modify_prot_start,
.ptep_modify_prot_commit = __ptep_modify_prot_commit,
#if CONFIG_PGTABLE_LEVELS >= 3
#ifdef CONFIG_X86_PAE
.set_pte_atomic = native_set_pte_atomic,
.pte_clear = native_pte_clear,
.pmd_clear = native_pmd_clear,
#endif
.set_pud = native_set_pud,
.set_pud_at = native_set_pud_at,
.pmd_val = PTE_IDENT,
.make_pmd = PTE_IDENT,
#if CONFIG_PGTABLE_LEVELS >= 4
.pud_val = PTE_IDENT,
.make_pud = PTE_IDENT,
.set_p4d = native_set_p4d,
#if CONFIG_PGTABLE_LEVELS >= 5
.p4d_val = PTE_IDENT,
.make_p4d = PTE_IDENT,
.set_pgd = native_set_pgd,
#endif /* CONFIG_PGTABLE_LEVELS >= 5 */
#endif /* CONFIG_PGTABLE_LEVELS >= 4 */
#endif /* CONFIG_PGTABLE_LEVELS >= 3 */
.pte_val = PTE_IDENT,
.pgd_val = PTE_IDENT,
.make_pte = PTE_IDENT,
.make_pgd = PTE_IDENT,
.dup_mmap = paravirt_nop,
.exit_mmap = paravirt_nop,
.activate_mm = paravirt_nop,
.lazy_mode = {
.enter = paravirt_nop,
.leave = paravirt_nop,
.flush = paravirt_nop,
},
.set_fixmap = native_set_fixmap,
};
EXPORT_SYMBOL_GPL(pv_time_ops);
EXPORT_SYMBOL (pv_cpu_ops);
EXPORT_SYMBOL (pv_mmu_ops);
EXPORT_SYMBOL_GPL(pv_info);
EXPORT_SYMBOL (pv_irq_ops);
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