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parasite: Move bootstrap code into parasite-head-x86-64.S

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Inline assembly is very convenient if a couple of
instructions is used but when it grows better to
move it out of wrapper C code and write in plain
assembly, after all we need a very precise control
in bootstrap code.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
This commit is contained in:
Cyrill Gorcunov 2012-04-18 15:44:00 +04:00 committed by Pavel Emelyanov
parent 5fe6f90b19
commit 88f7ae0186
5 changed files with 68 additions and 35 deletions
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14
Makefile.pie
View File

@ -1,5 +1,8 @@
GEN-OFFSETS := gen-offsets.sh
PASM-OBJS += parasite-head-x86-64.o
PASM-SRC += $(patsubst %.o,%.S,$(PASM-OBJS))
POBJS += parasite.o
PSRCS += $(patsubst %.o,%.c,$(POBJS))
@ -21,6 +24,11 @@ DEPS += $(patsubst %.o,%.d,$(POBJS))
DEPS += $(patsubst %.o,%.d,$(ROBJS))
PIEFLAGS := -fpie
ASMFLAGS := -D__ASSEMBLY__
$(PASM-OBJS): $(PASM-SRC)
$(E) " CC " $@
$(Q) $(CC) -c $(ASMFLAGS) $(CFLAGS) $(PIEFLAGS) $(patsubst %.o,%.S,$@) -o $@
$(POBJS): $(PSRCS) $(PASM-OBJS)
$(E) " CC " $@
@ -32,10 +40,10 @@ parasite-util-net.o: util-net.c
POBJS += parasite-util-net.o
$(PBLOB-BIN): $(PBLOB-LDS) $(POBJS)
$(PBLOB-BIN): $(PBLOB-LDS) $(POBJS) $(PASM-OBJS)
$(E) " GEN " $@
$(Q) $(LD) --oformat=binary -T $(PBLOB-LDS) -o $(PBLOB-BIN) $(POBJS)
$(Q) $(LD) --oformat=elf64-x86-64 -T $(PBLOB-LDS) -o $(PBLOB-BIN).o $(POBJS)
$(Q) $(LD) --oformat=binary -T $(PBLOB-LDS) -o $(PBLOB-BIN) $(POBJS) $(PASM-OBJS)
$(Q) $(LD) --oformat=elf64-x86-64 -T $(PBLOB-LDS) -o $(PBLOB-BIN).o $(POBJS) $(PASM-OBJS)
$(PBLOB-HDR): $(PBLOB-BIN) $(GEN-OFFSETS)
$(E) " GEN " $@

24
include/linkage.h Normal file
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@ -0,0 +1,24 @@
#ifndef LINKAGE_H_
#define LINKAGE_H_
#ifdef __ASSEMBLY__
#define __ALIGN .align 4, 0x90
#define __ALIGN_STR ".align 4, 0x90"
#define GLOBAL(name) \
.globl name; \
name:
#define ENTRY(name) \
.globl name; \
.type name, @function; \
__ALIGN; \
name:
#define END(sym) \
.size sym, . - sym
#endif /* __ASSEMBLY__ */
#endif /* LINKAGE_H_ */

13
include/parasite.h
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@ -1,6 +1,13 @@
#ifndef CR_PARASITE_H_
#define CR_PARASITE_H_
#define PARASITE_STACK_SIZE 2048
#define PARASITE_ARG_SIZE 8196
#define PARASITE_MAX_SIZE (64 << 10)
#ifndef __ASSEMBLY__
#include <sys/types.h>
#include <sys/un.h>
#include <limits.h>
@ -13,11 +20,6 @@
#define __head __used __section(.head.text)
#define PARASITE_STACK_SIZE 2048
#define PARASITE_ARG_SIZE 8196
#define PARASITE_MAX_SIZE (64 << 10)
enum {
PARASITE_CMD_INIT,
PARASITE_CMD_SET_LOGFD,
@ -102,4 +104,5 @@ struct parasite_drain_fd {
#define PARASITE_HEAD_ADDR(start) \
((start) + parasite_blob_offset____export_parasite_head_start)
#endif /* !__ASSEMBLY__ */
#endif /* CR_PARASITE_H_ */

24
parasite-head-x86-64.S Normal file
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@ -0,0 +1,24 @@
#include "linkage.h"
#include "parasite.h"
.section .head.text, "ax"
ENTRY(__export_parasite_head_start)
leaq __export_parasite_stack(%rip), %rsp
subq $16, %rsp
andq $~15, %rsp
pushq $0
movq %rsp, %rbp
movl __export_parasite_cmd(%rip), %edi
leaq __export_parasite_args(%rip), %rsi
call parasite_service
int $0x03
.align 8
__export_parasite_cmd:
.long 0
__export_parasite_args:
.long 0
.space PARASITE_ARG_SIZE,0
.space PARASITE_STACK_SIZE,0
__export_parasite_stack:
.long 0
END(__export_parasite_head_start)

28
parasite.c
View File

@ -444,7 +444,7 @@ static int fini(void)
return 0;
}
static int __used parasite_service(unsigned long cmd, void *args)
int __used parasite_service(unsigned long cmd, void *args)
{
BUILD_BUG_ON(sizeof(struct parasite_dump_pages_args) > PARASITE_ARG_SIZE);
BUILD_BUG_ON(sizeof(struct parasite_init_args) > PARASITE_ARG_SIZE);
@ -487,32 +487,6 @@ static int __used parasite_service(unsigned long cmd, void *args)
return -1;
}
static void __head __export_parasite_head(void)
{
/*
* The linker will handle the stack allocation.
*/
asm volatile("__export_parasite_head_start: \n"
"leaq __export_parasite_stack(%rip), %rsp \n"
"subq $16, %rsp \n"
"andq $~15, %rsp \n"
"pushq $0 \n"
"movq %rsp, %rbp \n"
"movl __export_parasite_cmd(%rip), %edi \n"
"leaq __export_parasite_args(%rip), %rsi \n"
"call parasite_service \n"
"int $0x03 \n"
".align 8 \n"
"__export_parasite_cmd: \n"
".long 0 \n"
"__export_parasite_args: \n"
".long 0 \n"
".space "__stringify(PARASITE_ARG_SIZE)",0 \n"
".space "__stringify(PARASITE_STACK_SIZE)", 0 \n"
"__export_parasite_stack: \n"
".long 0 \n");
}
#else /* CONFIG_X86_64 */
# error x86-32 bit mode not yet implemented
#endif /* CONFIG_X86_64 */