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[PATCH] paravirt: Patch inline replacements for paravirt intercepts 

It turns out that the most called ops, by several orders of magnitude,
are the interrupt manipulation ops.  These are obvious candidates for
patching, so mark them up and create infrastructure for it.

The method used is that the ops structure has a patch function, which
is called for each place which needs to be patched: this returns a
number of instructions (the rest are NOP-padded).

Usually we can spare a register (%eax) for the binary patched code to
use, but in a couple of critical places in entry.S we can't: we make
the clobbers explicit at the call site, and manually clobber the
allowed registers in debug mode as an extra check.

And:

Don't abuse CONFIG_DEBUG_KERNEL, add CONFIG_DEBUG_PARAVIRT.

And:

AK:  Fix warnings in x86-64 alternative.c build

And:

AK: Fix compilation with defconfig

And:

^From: Andrew Morton <akpm@osdl.org>

Some binutlises still like to emit references to __stop_parainstructions and
__start_parainstructions.

And:

AK: Fix warnings about unused variables when PARAVIRT is disabled.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Zachary Amsden <zach@vmware.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
This commit is contained in:
Rusty Russell 2006-12-07 02:14:08 +01:00 committed by Andi Kleen
parent d3561b7fa0
commit 139ec7c416
14 changed files with 459 additions and 188 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
arch/i386/Kconfig.debug
View File

@ -85,4 +85,14 @@ config DOUBLEFAULT
option saves about 4k and might cause you much additional grey
hair.
config DEBUG_PARAVIRT
bool "Enable some paravirtualization debugging"
default y
depends on PARAVIRT && DEBUG_KERNEL
help
Currently deliberately clobbers regs which are allowed to be
clobbered in inlined paravirt hooks, even in native mode.
If turning this off solves a problem, then DISABLE_INTERRUPTS() or
ENABLE_INTERRUPTS() is lying about what registers can be clobbered.
endmenu

63
arch/i386/kernel/alternative.c
View File

@ -124,6 +124,20 @@ static unsigned char** find_nop_table(void)
#endif /* CONFIG_X86_64 */
static void nop_out(void *insns, unsigned int len)
{
unsigned char **noptable = find_nop_table();
while (len > 0) {
unsigned int noplen = len;
if (noplen > ASM_NOP_MAX)
noplen = ASM_NOP_MAX;
memcpy(insns, noptable[noplen], noplen);
insns += noplen;
len -= noplen;
}
}
extern struct alt_instr __alt_instructions[], __alt_instructions_end[];
extern struct alt_instr __smp_alt_instructions[], __smp_alt_instructions_end[];
extern u8 *__smp_locks[], *__smp_locks_end[];
@ -138,10 +152,9 @@ extern u8 __smp_alt_begin[], __smp_alt_end[];
void apply_alternatives(struct alt_instr *start, struct alt_instr *end)
{
unsigned char **noptable = find_nop_table();
struct alt_instr *a;
u8 *instr;
int diff, i, k;
int diff;
DPRINTK("%s: alt table %p -> %p\n", __FUNCTION__, start, end);
for (a = start; a < end; a++) {
@ -159,13 +172,7 @@ void apply_alternatives(struct alt_instr *start, struct alt_instr *end)
#endif
memcpy(instr, a->replacement, a->replacementlen);
diff = a->instrlen - a->replacementlen;
/* Pad the rest with nops */
for (i = a->replacementlen; diff > 0; diff -= k, i += k) {
k = diff;
if (k > ASM_NOP_MAX)
k = ASM_NOP_MAX;
memcpy(a->instr + i, noptable[k], k);
}
nop_out(instr + a->replacementlen, diff);
}
}
@ -209,7 +216,6 @@ static void alternatives_smp_lock(u8 **start, u8 **end, u8 *text, u8 *text_end)
static void alternatives_smp_unlock(u8 **start, u8 **end, u8 *text, u8 *text_end)
{
unsigned char **noptable = find_nop_table();
u8 **ptr;
for (ptr = start; ptr < end; ptr++) {
@ -217,7 +223,7 @@ static void alternatives_smp_unlock(u8 **start, u8 **end, u8 *text, u8 *text_end
continue;
if (*ptr > text_end)
continue;
**ptr = noptable[1][0];
nop_out(*ptr, 1);
};
}
@ -343,6 +349,40 @@ void alternatives_smp_switch(int smp)
#endif
#ifdef CONFIG_PARAVIRT
void apply_paravirt(struct paravirt_patch *start, struct paravirt_patch *end)
{
struct paravirt_patch *p;
for (p = start; p < end; p++) {
unsigned int used;
used = paravirt_ops.patch(p->instrtype, p->clobbers, p->instr,
p->len);
#ifdef CONFIG_DEBUG_PARAVIRT
{
int i;
/* Deliberately clobber regs using "not %reg" to find bugs. */
for (i = 0; i < 3; i++) {
if (p->len - used >= 2 && (p->clobbers & (1 << i))) {
memcpy(p->instr + used, "\xf7\xd0", 2);
p->instr[used+1] |= i;
used += 2;
}
}
}
#endif
/* Pad the rest with nops */
nop_out(p->instr + used, p->len - used);
}
/* Sync to be conservative, in case we patched following instructions */
sync_core();
}
extern struct paravirt_patch __start_parainstructions[],
__stop_parainstructions[];
#endif /* CONFIG_PARAVIRT */
void __init alternative_instructions(void)
{
unsigned long flags;
@ -390,5 +430,6 @@ void __init alternative_instructions(void)
alternatives_smp_switch(0);
}
#endif
apply_paravirt(__start_parainstructions, __stop_parainstructions);
local_irq_restore(flags);
}

39
arch/i386/kernel/entry.S
View File

@ -53,6 +53,19 @@
#include <asm/dwarf2.h>
#include "irq_vectors.h"
/*
* We use macros for low-level operations which need to be overridden
* for paravirtualization. The following will never clobber any registers:
* INTERRUPT_RETURN (aka. "iret")
* GET_CR0_INTO_EAX (aka. "movl %cr0, %eax")
* ENABLE_INTERRUPTS_SYSEXIT (aka "sti; sysexit").
*
* For DISABLE_INTERRUPTS/ENABLE_INTERRUPTS (aka "cli"/"sti"), you must
* specify what registers can be overwritten (CLBR_NONE, CLBR_EAX/EDX/ECX/ANY).
* Allowing a register to be clobbered can shrink the paravirt replacement
* enough to patch inline, increasing performance.
*/
#define nr_syscalls ((syscall_table_size)/4)
CF_MASK = 0x00000001
@ -63,9 +76,9 @@ NT_MASK = 0x00004000
VM_MASK = 0x00020000
#ifdef CONFIG_PREEMPT
#define preempt_stop DISABLE_INTERRUPTS; TRACE_IRQS_OFF
#define preempt_stop(clobbers) DISABLE_INTERRUPTS(clobbers); TRACE_IRQS_OFF
#else
#define preempt_stop
#define preempt_stop(clobbers)
#define resume_kernel restore_nocheck
#endif
@ -226,7 +239,7 @@ ENTRY(ret_from_fork)
ALIGN
RING0_PTREGS_FRAME
ret_from_exception:
preempt_stop
preempt_stop(CLBR_ANY)
ret_from_intr:
GET_THREAD_INFO(%ebp)
check_userspace:
@ -237,7 +250,7 @@ check_userspace:
jb resume_kernel # not returning to v8086 or userspace
ENTRY(resume_userspace)
DISABLE_INTERRUPTS # make sure we don't miss an interrupt
DISABLE_INTERRUPTS(CLBR_ANY) # make sure we don't miss an interrupt
# setting need_resched or sigpending
# between sampling and the iret
movl TI_flags(%ebp), %ecx
@ -248,7 +261,7 @@ ENTRY(resume_userspace)
#ifdef CONFIG_PREEMPT
ENTRY(resume_kernel)
DISABLE_INTERRUPTS
DISABLE_INTERRUPTS(CLBR_ANY)
cmpl $0,TI_preempt_count(%ebp) # non-zero preempt_count ?
jnz restore_nocheck
need_resched:
@ -277,7 +290,7 @@ sysenter_past_esp:
* No need to follow this irqs on/off section: the syscall
* disabled irqs and here we enable it straight after entry:
*/
ENABLE_INTERRUPTS
ENABLE_INTERRUPTS(CLBR_NONE)
pushl $(__USER_DS)
CFI_ADJUST_CFA_OFFSET 4
/*CFI_REL_OFFSET ss, 0*/
@ -322,7 +335,7 @@ sysenter_past_esp:
jae syscall_badsys
call *sys_call_table(,%eax,4)
movl %eax,PT_EAX(%esp)
DISABLE_INTERRUPTS
DISABLE_INTERRUPTS(CLBR_ECX|CLBR_EDX)
TRACE_IRQS_OFF
movl TI_flags(%ebp), %ecx
testw $_TIF_ALLWORK_MASK, %cx
@ -364,7 +377,7 @@ syscall_call:
call *sys_call_table(,%eax,4)
movl %eax,PT_EAX(%esp) # store the return value
syscall_exit:
DISABLE_INTERRUPTS # make sure we don't miss an interrupt
DISABLE_INTERRUPTS(CLBR_ANY) # make sure we don't miss an interrupt
# setting need_resched or sigpending
# between sampling and the iret
TRACE_IRQS_OFF
@ -393,7 +406,7 @@ restore_nocheck_notrace:
.section .fixup,"ax"
iret_exc:
TRACE_IRQS_ON
ENABLE_INTERRUPTS
ENABLE_INTERRUPTS(CLBR_NONE)
pushl $0 # no error code
pushl $do_iret_error
jmp error_code
@ -436,7 +449,7 @@ ldt_ss:
CFI_ADJUST_CFA_OFFSET 4
pushl %eax
CFI_ADJUST_CFA_OFFSET 4
DISABLE_INTERRUPTS
DISABLE_INTERRUPTS(CLBR_EAX)
TRACE_IRQS_OFF
lss (%esp), %esp
CFI_ADJUST_CFA_OFFSET -8
@ -451,7 +464,7 @@ work_pending:
jz work_notifysig
work_resched:
call schedule
DISABLE_INTERRUPTS # make sure we don't miss an interrupt
DISABLE_INTERRUPTS(CLBR_ANY) # make sure we don't miss an interrupt
# setting need_resched or sigpending
# between sampling and the iret
TRACE_IRQS_OFF
@ -509,7 +522,7 @@ syscall_exit_work:
testb $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SINGLESTEP), %cl
jz work_pending
TRACE_IRQS_ON
ENABLE_INTERRUPTS # could let do_syscall_trace() call
ENABLE_INTERRUPTS(CLBR_ANY) # could let do_syscall_trace() call
# schedule() instead
movl %esp, %eax
movl $1, %edx
@ -693,7 +706,7 @@ ENTRY(device_not_available)
GET_CR0_INTO_EAX
testl $0x4, %eax # EM (math emulation bit)
jne device_not_available_emulate
preempt_stop
preempt_stop(CLBR_ANY)
call math_state_restore
jmp ret_from_exception
device_not_available_emulate:

11
arch/i386/kernel/module.c
View File

@ -108,7 +108,8 @@ int module_finalize(const Elf_Ehdr *hdr,
const Elf_Shdr *sechdrs,
struct module *me)
{
const Elf_Shdr *s, *text = NULL, *alt = NULL, *locks = NULL;
const Elf_Shdr *s, *text = NULL, *alt = NULL, *locks = NULL,
*para = NULL;
char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
@ -118,6 +119,8 @@ int module_finalize(const Elf_Ehdr *hdr,
alt = s;
if (!strcmp(".smp_locks", secstrings + s->sh_name))
locks= s;
if (!strcmp(".parainstructions", secstrings + s->sh_name))
para = s;
}
if (alt) {
@ -132,6 +135,12 @@ int module_finalize(const Elf_Ehdr *hdr,
lseg, lseg + locks->sh_size,
tseg, tseg + text->sh_size);
}
if (para) {
void *pseg = (void *)para->sh_addr;
apply_paravirt(pseg, pseg + para->sh_size);
}
return 0;
}

44
arch/i386/kernel/paravirt.c
View File

@ -45,6 +45,49 @@ char *memory_setup(void)
return paravirt_ops.memory_setup();
}
/* Simple instruction patching code. */
#define DEF_NATIVE(name, code) \
extern const char start_##name[], end_##name[]; \
asm("start_" #name ": " code "; end_" #name ":")
DEF_NATIVE(cli, "cli");
DEF_NATIVE(sti, "sti");
DEF_NATIVE(popf, "push %eax; popf");
DEF_NATIVE(pushf, "pushf; pop %eax");
DEF_NATIVE(pushf_cli, "pushf; pop %eax; cli");
DEF_NATIVE(iret, "iret");
DEF_NATIVE(sti_sysexit, "sti; sysexit");
static const struct native_insns
{
const char *start, *end;
} native_insns[] = {
[PARAVIRT_IRQ_DISABLE] = { start_cli, end_cli },
[PARAVIRT_IRQ_ENABLE] = { start_sti, end_sti },
[PARAVIRT_RESTORE_FLAGS] = { start_popf, end_popf },
[PARAVIRT_SAVE_FLAGS] = { start_pushf, end_pushf },
[PARAVIRT_SAVE_FLAGS_IRQ_DISABLE] = { start_pushf_cli, end_pushf_cli },
[PARAVIRT_INTERRUPT_RETURN] = { start_iret, end_iret },
[PARAVIRT_STI_SYSEXIT] = { start_sti_sysexit, end_sti_sysexit },
};
static unsigned native_patch(u8 type, u16 clobbers, void *insns, unsigned len)
{
unsigned int insn_len;
/* Don't touch it if we don't have a replacement */
if (type >= ARRAY_SIZE(native_insns) || !native_insns[type].start)
return len;
insn_len = native_insns[type].end - native_insns[type].start;
/* Similarly if we can't fit replacement. */
if (len < insn_len)
return len;
memcpy(insns, native_insns[type].start, insn_len);
return insn_len;
}
static fastcall unsigned long native_get_debugreg(int regno)
{
unsigned long val = 0; /* Damn you, gcc! */
@ -349,6 +392,7 @@ struct paravirt_ops paravirt_ops = {
.paravirt_enabled = 0,
.kernel_rpl = 0,
.patch = native_patch,
.banner = default_banner,
.arch_setup = native_nop,
.memory_setup = machine_specific_memory_setup,

6
arch/i386/kernel/vmlinux.lds.S
View File

@ -165,6 +165,12 @@ SECTIONS
.altinstr_replacement : AT(ADDR(.altinstr_replacement) - LOAD_OFFSET) {
*(.altinstr_replacement)
}
. = ALIGN(4);
__start_parainstructions = .;
.parainstructions : AT(ADDR(.parainstructions) - LOAD_OFFSET) {
*(.parainstructions)
}
__stop_parainstructions = .;
/* .exit.text is discard at runtime, not link time, to deal with references
from .altinstructions and .eh_frame */
.exit.text : AT(ADDR(.exit.text) - LOAD_OFFSET) { *(.exit.text) }

13
include/asm-i386/alternative.h
View File

@ -4,7 +4,7 @@
#ifdef __KERNEL__
#include <asm/types.h>
#include <linux/stddef.h>
#include <linux/types.h>
struct alt_instr {
@ -118,4 +118,15 @@ static inline void alternatives_smp_switch(int smp) {}
#define LOCK_PREFIX ""
#endif
struct paravirt_patch;
#ifdef CONFIG_PARAVIRT
void apply_paravirt(struct paravirt_patch *start, struct paravirt_patch *end);
#else
static inline void
apply_paravirt(struct paravirt_patch *start, struct paravirt_patch *end)
{}
#define __start_parainstructions NULL
#define __stop_parainstructions NULL
#endif
#endif /* _I386_ALTERNATIVE_H */

41
include/asm-i386/desc.h
View File

@ -81,6 +81,10 @@ static inline void load_TLS(struct thread_struct *t, unsigned int cpu)
#undef C
}
#define write_ldt_entry(dt, entry, a, b) write_dt_entry(dt, entry, a, b)
#define write_gdt_entry(dt, entry, a, b) write_dt_entry(dt, entry, a, b)
#define write_idt_entry(dt, entry, a, b) write_dt_entry(dt, entry, a, b)
static inline void write_dt_entry(void *dt, int entry, __u32 entry_a, __u32 entry_b)
{
__u32 *lp = (__u32 *)((char *)dt + entry*8);
@ -88,26 +92,6 @@ static inline void write_dt_entry(void *dt, int entry, __u32 entry_a, __u32 entr
*(lp+1) = entry_b;
}
#define write_ldt_entry(dt, entry, a, b) write_dt_entry(dt, entry, a, b)
#define write_gdt_entry(dt, entry, a, b) write_dt_entry(dt, entry, a, b)
#define write_idt_entry(dt, entry, a, b) write_dt_entry(dt, entry, a, b)
static inline void _set_gate(int gate, unsigned int type, void *addr, unsigned short seg)
{
__u32 a, b;
pack_gate(&a, &b, (unsigned long)addr, seg, type, 0);
write_idt_entry(idt_table, gate, a, b);
}
static inline void __set_tss_desc(unsigned int cpu, unsigned int entry, const void *addr)
{
__u32 a, b;
pack_descriptor(&a, &b, (unsigned long)addr,
offsetof(struct tss_struct, __cacheline_filler) - 1,
DESCTYPE_TSS, 0);
write_gdt_entry(get_cpu_gdt_table(cpu), entry, a, b);
}
#define set_ldt native_set_ldt
#endif /* CONFIG_PARAVIRT */
@ -128,6 +112,23 @@ static inline fastcall void native_set_ldt(const void *addr,
}
}
static inline void _set_gate(int gate, unsigned int type, void *addr, unsigned short seg)
{
__u32 a, b;
pack_gate(&a, &b, (unsigned long)addr, seg, type, 0);
write_idt_entry(idt_table, gate, a, b);
}
static inline void __set_tss_desc(unsigned int cpu, unsigned int entry, const void *addr)
{
__u32 a, b;
pack_descriptor(&a, &b, (unsigned long)addr,
offsetof(struct tss_struct, __cacheline_filler) - 1,
DESCTYPE_TSS, 0);
write_gdt_entry(get_cpu_gdt_table(cpu), entry, a, b);
}
#define set_tss_desc(cpu,addr) __set_tss_desc(cpu, GDT_ENTRY_TSS, addr)
#define LDT_entry_a(info) \

4
include/asm-i386/irqflags.h
View File

@ -79,8 +79,8 @@ static inline unsigned long __raw_local_irq_save(void)
}
#else
#define DISABLE_INTERRUPTS cli
#define ENABLE_INTERRUPTS sti
#define DISABLE_INTERRUPTS(clobbers) cli
#define ENABLE_INTERRUPTS(clobbers) sti
#define ENABLE_INTERRUPTS_SYSEXIT sti; sysexit
#define INTERRUPT_RETURN iret
#define GET_CR0_INTO_EAX movl %cr0, %eax

189
include/asm-i386/paravirt.h
View File

@ -3,8 +3,26 @@
/* Various instructions on x86 need to be replaced for
* para-virtualization: those hooks are defined here. */
#include <linux/linkage.h>
#include <linux/stringify.h>
#ifdef CONFIG_PARAVIRT
/* These are the most performance critical ops, so we want to be able to patch
* callers */
#define PARAVIRT_IRQ_DISABLE 0
#define PARAVIRT_IRQ_ENABLE 1
#define PARAVIRT_RESTORE_FLAGS 2
#define PARAVIRT_SAVE_FLAGS 3
#define PARAVIRT_SAVE_FLAGS_IRQ_DISABLE 4
#define PARAVIRT_INTERRUPT_RETURN 5
#define PARAVIRT_STI_SYSEXIT 6
/* Bitmask of what can be clobbered: usually at least eax. */
#define CLBR_NONE 0x0
#define CLBR_EAX 0x1
#define CLBR_ECX 0x2
#define CLBR_EDX 0x4
#define CLBR_ANY 0x7
#ifndef __ASSEMBLY__
struct thread_struct;
struct Xgt_desc_struct;
@ -15,6 +33,15 @@ struct paravirt_ops
int paravirt_enabled;
const char *name;
/*
* Patch may replace one of the defined code sequences with arbitrary
* code, subject to the same register constraints. This generally
* means the code is not free to clobber any registers other than EAX.
* The patch function should return the number of bytes of code
* generated, as we nop pad the rest in generic code.
*/
unsigned (*patch)(u8 type, u16 clobber, void *firstinsn, unsigned len);
void (*arch_setup)(void);
char *(*memory_setup)(void);
void (*init_IRQ)(void);
@ -147,35 +174,6 @@ static inline void __cpuid(unsigned int *eax, unsigned int *ebx,
#define read_cr4_safe(x) paravirt_ops.read_cr4_safe()
#define write_cr4(x) paravirt_ops.write_cr4(x)
static inline unsigned long __raw_local_save_flags(void)
{
return paravirt_ops.save_fl();
}
static inline void raw_local_irq_restore(unsigned long flags)
{
return paravirt_ops.restore_fl(flags);
}
static inline void raw_local_irq_disable(void)
{
paravirt_ops.irq_disable();
}
static inline void raw_local_irq_enable(void)
{
paravirt_ops.irq_enable();
}
static inline unsigned long __raw_local_irq_save(void)
{
unsigned long flags = paravirt_ops.save_fl();
paravirt_ops.irq_disable();
return flags;
}
static inline void raw_safe_halt(void)
{
paravirt_ops.safe_halt();
@ -267,15 +265,134 @@ static inline void slow_down_io(void) {
#endif
}
#define CLI_STRING "pushl %eax; pushl %ecx; pushl %edx; call *paravirt_ops+PARAVIRT_irq_disable; popl %edx; popl %ecx; popl %eax"
#define STI_STRING "pushl %eax; pushl %ecx; pushl %edx; call *paravirt_ops+PARAVIRT_irq_enable; popl %edx; popl %ecx; popl %eax"
/* These all sit in the .parainstructions section to tell us what to patch. */
struct paravirt_patch {
u8 *instr; /* original instructions */
u8 instrtype; /* type of this instruction */
u8 len; /* length of original instruction */
u16 clobbers; /* what registers you may clobber */
};
#define paravirt_alt(insn_string, typenum, clobber) \
"771:\n\t" insn_string "\n" "772:\n" \
".pushsection .parainstructions,\"a\"\n" \
" .long 771b\n" \
" .byte " __stringify(typenum) "\n" \
" .byte 772b-771b\n" \
" .short " __stringify(clobber) "\n" \
".popsection"
static inline unsigned long __raw_local_save_flags(void)
{
unsigned long f;
__asm__ __volatile__(paravirt_alt( "pushl %%ecx; pushl %%edx;"
"call *%1;"
"popl %%edx; popl %%ecx",
PARAVIRT_SAVE_FLAGS, CLBR_NONE)
: "=a"(f): "m"(paravirt_ops.save_fl)
: "memory", "cc");
return f;
}
static inline void raw_local_irq_restore(unsigned long f)
{
__asm__ __volatile__(paravirt_alt( "pushl %%ecx; pushl %%edx;"
"call *%1;"
"popl %%edx; popl %%ecx",
PARAVIRT_RESTORE_FLAGS, CLBR_EAX)
: "=a"(f) : "m" (paravirt_ops.restore_fl), "0"(f)
: "memory", "cc");
}
static inline void raw_local_irq_disable(void)
{
__asm__ __volatile__(paravirt_alt( "pushl %%ecx; pushl %%edx;"
"call *%0;"
"popl %%edx; popl %%ecx",
PARAVIRT_IRQ_DISABLE, CLBR_EAX)
: : "m" (paravirt_ops.irq_disable)
: "memory", "eax", "cc");
}
static inline void raw_local_irq_enable(void)
{
__asm__ __volatile__(paravirt_alt( "pushl %%ecx; pushl %%edx;"
"call *%0;"
"popl %%edx; popl %%ecx",
PARAVIRT_IRQ_ENABLE, CLBR_EAX)
: : "m" (paravirt_ops.irq_enable)
: "memory", "eax", "cc");
}
static inline unsigned long __raw_local_irq_save(void)
{
unsigned long f;
__asm__ __volatile__(paravirt_alt( "pushl %%ecx; pushl %%edx;"
"call *%1; pushl %%eax;"
"call *%2; popl %%eax;"
"popl %%edx; popl %%ecx",
PARAVIRT_SAVE_FLAGS_IRQ_DISABLE,
CLBR_NONE)
: "=a"(f)
: "m" (paravirt_ops.save_fl),
"m" (paravirt_ops.irq_disable)
: "memory", "cc");
return f;
}
#define CLI_STRING paravirt_alt("pushl %%ecx; pushl %%edx;" \
"call *paravirt_ops+%c[irq_disable];" \
"popl %%edx; popl %%ecx", \
PARAVIRT_IRQ_DISABLE, CLBR_EAX)
#define STI_STRING paravirt_alt("pushl %%ecx; pushl %%edx;" \
"call *paravirt_ops+%c[irq_enable];" \
"popl %%edx; popl %%ecx", \
PARAVIRT_IRQ_ENABLE, CLBR_EAX)
#define CLI_STI_CLOBBERS , "%eax"
#define CLI_STI_INPUT_ARGS \
, \
[irq_disable] "i" (offsetof(struct paravirt_ops, irq_disable)), \
[irq_enable] "i" (offsetof(struct paravirt_ops, irq_enable))
#else /* __ASSEMBLY__ */
#define INTERRUPT_RETURN jmp *%cs:paravirt_ops+PARAVIRT_iret
#define DISABLE_INTERRUPTS pushl %eax; pushl %ecx; pushl %edx; call *paravirt_ops+PARAVIRT_irq_disable; popl %edx; popl %ecx; popl %eax
#define ENABLE_INTERRUPTS pushl %eax; pushl %ecx; pushl %edx; call *%cs:paravirt_ops+PARAVIRT_irq_enable; popl %edx; popl %ecx; popl %eax
#define ENABLE_INTERRUPTS_SYSEXIT jmp *%cs:paravirt_ops+PARAVIRT_irq_enable_sysexit
#define GET_CR0_INTO_EAX call *paravirt_ops+PARAVIRT_read_cr0
#define PARA_PATCH(ptype, clobbers, ops) \
771:; \
ops; \
772:; \
.pushsection .parainstructions,"a"; \
.long 771b; \
.byte ptype; \
.byte 772b-771b; \
.short clobbers; \
.popsection
#define INTERRUPT_RETURN \
PARA_PATCH(PARAVIRT_INTERRUPT_RETURN, CLBR_ANY, \
jmp *%cs:paravirt_ops+PARAVIRT_iret)
#define DISABLE_INTERRUPTS(clobbers) \
PARA_PATCH(PARAVIRT_IRQ_DISABLE, clobbers, \
pushl %ecx; pushl %edx; \
call *paravirt_ops+PARAVIRT_irq_disable; \
popl %edx; popl %ecx) \
#define ENABLE_INTERRUPTS(clobbers) \
PARA_PATCH(PARAVIRT_IRQ_ENABLE, clobbers, \
pushl %ecx; pushl %edx; \
call *%cs:paravirt_ops+PARAVIRT_irq_enable; \
popl %edx; popl %ecx)
#define ENABLE_INTERRUPTS_SYSEXIT \
PARA_PATCH(PARAVIRT_STI_SYSEXIT, CLBR_ANY, \
jmp *%cs:paravirt_ops+PARAVIRT_irq_enable_sysexit)
#define GET_CR0_INTO_EAX \
call *paravirt_ops+PARAVIRT_read_cr0
#endif /* __ASSEMBLY__ */
#endif /* CONFIG_PARAVIRT */
#endif /* __ASM_PARAVIRT_H */

198
include/asm-i386/processor.h
View File

@ -156,59 +156,6 @@ static inline fastcall void native_cpuid(unsigned int *eax, unsigned int *ebx,
: "0" (*eax), "2" (*ecx));
}
/*
* Generic CPUID function
* clear %ecx since some cpus (Cyrix MII) do not set or clear %ecx
* resulting in stale register contents being returned.
*/
static inline void cpuid(unsigned int op, unsigned int *eax, unsigned int *ebx, unsigned int *ecx, unsigned int *edx)
{
*eax = op;
*ecx = 0;
__cpuid(eax, ebx, ecx, edx);
}
/* Some CPUID calls want 'count' to be placed in ecx */
static inline void cpuid_count(int op, int count, int *eax, int *ebx, int *ecx,
int *edx)
{
*eax = op;
*ecx = count;
__cpuid(eax, ebx, ecx, edx);
}
/*
* CPUID functions returning a single datum
*/
static inline unsigned int cpuid_eax(unsigned int op)
{
unsigned int eax, ebx, ecx, edx;
cpuid(op, &eax, &ebx, &ecx, &edx);
return eax;
}
static inline unsigned int cpuid_ebx(unsigned int op)
{
unsigned int eax, ebx, ecx, edx;
cpuid(op, &eax, &ebx, &ecx, &edx);
return ebx;
}
static inline unsigned int cpuid_ecx(unsigned int op)
{
unsigned int eax, ebx, ecx, edx;
cpuid(op, &eax, &ebx, &ecx, &edx);
return ecx;
}
static inline unsigned int cpuid_edx(unsigned int op)
{
unsigned int eax, ebx, ecx, edx;
cpuid(op, &eax, &ebx, &ecx, &edx);
return edx;
}
#define load_cr3(pgdir) write_cr3(__pa(pgdir))
/*
@ -491,22 +438,6 @@ struct thread_struct {
.io_bitmap = { [ 0 ... IO_BITMAP_LONGS] = ~0 }, \
}
#ifdef CONFIG_PARAVIRT
#include <asm/paravirt.h>
#else
#define paravirt_enabled() 0
#define __cpuid native_cpuid
static inline void load_esp0(struct tss_struct *tss, struct thread_struct *thread)
{
tss->esp0 = thread->esp0;
/* This can only happen when SEP is enabled, no need to test "SEP"arately */
if (unlikely(tss->ss1 != thread->sysenter_cs)) {
tss->ss1 = thread->sysenter_cs;
wrmsr(MSR_IA32_SYSENTER_CS, thread->sysenter_cs, 0);
}
}
#define start_thread(regs, new_eip, new_esp) do { \
__asm__("movl %0,%%fs": :"r" (0)); \
regs->xgs = 0; \
@ -519,36 +450,6 @@ static inline void load_esp0(struct tss_struct *tss, struct thread_struct *threa
regs->esp = new_esp; \
} while (0)
/*
* These special macros can be used to get or set a debugging register
*/
#define get_debugreg(var, register) \
__asm__("movl %%db" #register ", %0" \
:"=r" (var))
#define set_debugreg(value, register) \
__asm__("movl %0,%%db" #register \
: /* no output */ \
:"r" (value))
#define set_iopl_mask native_set_iopl_mask
#endif /* CONFIG_PARAVIRT */
/*
* Set IOPL bits in EFLAGS from given mask
*/
static fastcall inline void native_set_iopl_mask(unsigned mask)
{
unsigned int reg;
__asm__ __volatile__ ("pushfl;"
"popl %0;"
"andl %1, %0;"
"orl %2, %0;"
"pushl %0;"
"popfl"
: "=&r" (reg)
: "i" (~X86_EFLAGS_IOPL), "r" (mask));
}
/* Forward declaration, a strange C thing */
struct task_struct;
struct mm_struct;
@ -640,6 +541,105 @@ static inline void rep_nop(void)
#define cpu_relax() rep_nop()
#ifdef CONFIG_PARAVIRT
#include <asm/paravirt.h>
#else
#define paravirt_enabled() 0
#define __cpuid native_cpuid
static inline void load_esp0(struct tss_struct *tss, struct thread_struct *thread)
{
tss->esp0 = thread->esp0;
/* This can only happen when SEP is enabled, no need to test "SEP"arately */
if (unlikely(tss->ss1 != thread->sysenter_cs)) {
tss->ss1 = thread->sysenter_cs;
wrmsr(MSR_IA32_SYSENTER_CS, thread->sysenter_cs, 0);
}
}
/*
* These special macros can be used to get or set a debugging register
*/
#define get_debugreg(var, register) \
__asm__("movl %%db" #register ", %0" \
:"=r" (var))
#define set_debugreg(value, register) \
__asm__("movl %0,%%db" #register \
: /* no output */ \
:"r" (value))
#define set_iopl_mask native_set_iopl_mask
#endif /* CONFIG_PARAVIRT */
/*
* Set IOPL bits in EFLAGS from given mask
*/
static fastcall inline void native_set_iopl_mask(unsigned mask)
{
unsigned int reg;
__asm__ __volatile__ ("pushfl;"
"popl %0;"
"andl %1, %0;"
"orl %2, %0;"
"pushl %0;"
"popfl"
: "=&r" (reg)
: "i" (~X86_EFLAGS_IOPL), "r" (mask));
}
/*
* Generic CPUID function
* clear %ecx since some cpus (Cyrix MII) do not set or clear %ecx
* resulting in stale register contents being returned.
*/
static inline void cpuid(unsigned int op, unsigned int *eax, unsigned int *ebx, unsigned int *ecx, unsigned int *edx)
{
*eax = op;
*ecx = 0;
__cpuid(eax, ebx, ecx, edx);
}
/* Some CPUID calls want 'count' to be placed in ecx */
static inline void cpuid_count(int op, int count, int *eax, int *ebx, int *ecx,
int *edx)
{
*eax = op;
*ecx = count;
__cpuid(eax, ebx, ecx, edx);
}
/*
* CPUID functions returning a single datum
*/
static inline unsigned int cpuid_eax(unsigned int op)
{
unsigned int eax, ebx, ecx, edx;
cpuid(op, &eax, &ebx, &ecx, &edx);
return eax;
}
static inline unsigned int cpuid_ebx(unsigned int op)
{
unsigned int eax, ebx, ecx, edx;
cpuid(op, &eax, &ebx, &ecx, &edx);
return ebx;
}
static inline unsigned int cpuid_ecx(unsigned int op)
{
unsigned int eax, ebx, ecx, edx;
cpuid(op, &eax, &ebx, &ecx, &edx);
return ecx;
}
static inline unsigned int cpuid_edx(unsigned int op)
{
unsigned int eax, ebx, ecx, edx;
cpuid(op, &eax, &ebx, &ecx, &edx);
return edx;
}
/* generic versions from gas */
#define GENERIC_NOP1 ".byte 0x90\n"
#define GENERIC_NOP2 ".byte 0x89,0xf6\n"

15
include/asm-i386/spinlock.h
View File

@ -12,6 +12,8 @@
#else
#define CLI_STRING "cli"
#define STI_STRING "sti"
#define CLI_STI_CLOBBERS
#define CLI_STI_INPUT_ARGS
#endif /* CONFIG_PARAVIRT */
/*
@ -57,25 +59,28 @@ static inline void __raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long fla
{
asm volatile(
"\n1:\t"
LOCK_PREFIX " ; decb %0\n\t"
LOCK_PREFIX " ; decb %[slock]\n\t"
"jns 5f\n"
"2:\t"
"testl $0x200, %1\n\t"
"testl $0x200, %[flags]\n\t"
"jz 4f\n\t"
STI_STRING "\n"
"3:\t"
"rep;nop\n\t"
"cmpb $0, %0\n\t"
"cmpb $0, %[slock]\n\t"
"jle 3b\n\t"
CLI_STRING "\n\t"
"jmp 1b\n"
"4:\t"
"rep;nop\n\t"
"cmpb $0, %0\n\t"
"cmpb $0, %[slock]\n\t"
"jg 1b\n\t"
"jmp 4b\n"
"5:\n\t"
: "+m" (lock->slock) : "r" (flags) : "memory");
: [slock] "+m" (lock->slock)
: [flags] "r" (flags)
CLI_STI_INPUT_ARGS
: "memory" CLI_STI_CLOBBERS);
}
#endif

12
include/asm-x86_64/alternative.h
View File

@ -4,6 +4,7 @@
#ifdef __KERNEL__
#include <linux/types.h>
#include <linux/stddef.h>
#include <asm/cpufeature.h>
struct alt_instr {
@ -133,4 +134,15 @@ static inline void alternatives_smp_switch(int smp) {}
#define LOCK_PREFIX ""
#endif
struct paravirt_patch;
#ifdef CONFIG_PARAVIRT
void apply_paravirt(struct paravirt_patch *start, struct paravirt_patch *end);
#else
static inline void
apply_paravirt(struct paravirt_patch *start, struct paravirt_patch *end)
{}
#define __start_parainstructions NULL
#define __stop_parainstructions NULL
#endif
#endif /* _X86_64_ALTERNATIVE_H */

2
scripts/mod/modpost.c
View File

@ -911,6 +911,7 @@ static int init_section_ref_ok(const char *name)
".toc1", /* used by ppc64 */
".stab",
".rodata",
".parainstructions",
".text.lock",
"__bug_table", /* used by powerpc for BUG() */
".pci_fixup_header",
@ -931,6 +932,7 @@ static int init_section_ref_ok(const char *name)
".altinstructions",
".eh_frame",
".debug",
".parainstructions",
NULL
};
/* part of section name */