parasite-syscall: get rid of code_syscall{,size} globals

I think, we may safely remove this exports, as:
- code_syscall is used only in one function, which now will have
  it as a parameter;
- code_syscall_size must be equall to BUILTIN_SYSCALL_SIZE under
  BUILD_BUG_ON, so BUILTIN_SYSCALL_SIZE may be used instead.
  (see ptrace(2) - align restriction to PTRACE_PEEKUSER).

This will reduce arch-depended code coupling a little.

(and I also interested in this because of I need __parasite_execute_syscall
to execute 32-bit syscall code on x86_64, which I prefer to leave without
some CONFIG_X86_64 as it's generic code)

Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com>
Reviewed-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

criu/arch/aarch64/crtools.c

@@ -27,11 +27,12 @@ const char code_syscall[] = {
 	0x00, 0x00, 0x20, 0xd4		/* BRK #0 */
 };
 
-const int code_syscall_size = round_up(sizeof(code_syscall), sizeof(long));
+static const int
+code_syscall_aligned = round_up(sizeof(code_syscall), sizeof(long));
 
 static inline void __always_unused __check_code_syscall(void)
 {
-	BUILD_BUG_ON(sizeof(code_syscall) != BUILTIN_SYSCALL_SIZE);
+	BUILD_BUG_ON(code_syscall_aligned != BUILTIN_SYSCALL_SIZE);
 	BUILD_BUG_ON(!is_log2(sizeof(code_syscall)));
 }
 
@@ -71,7 +72,7 @@ int syscall_seized(struct parasite_ctl *ctl, int nr, unsigned long *ret,
 	regs.regs[6] = 0;
 	regs.regs[7] = 0;
 
-	err = __parasite_execute_syscall(ctl, &regs);
+	err = __parasite_execute_syscall(ctl, &regs, code_syscall);
 
 	*ret = regs.regs[0];
 	return err;

criu/arch/aarch64/include/asm/parasite-syscall.h

@@ -6,9 +6,6 @@ struct parasite_ctl;
 #define ARCH_SI_TRAP TRAP_BRKPT
 
 
-extern const char code_syscall[];
-extern const int code_syscall_size;
-
 void parasite_setup_regs(unsigned long new_ip, void *stack, user_regs_struct_t *regs);
 
 void *mmap_seized(struct parasite_ctl *ctl,

criu/arch/arm/crtools.c

@@ -28,11 +28,12 @@ const char code_syscall[] = {
 	0xf0, 0x01, 0xf0, 0xe7          /* UDF #32 */
 };
 
-const int code_syscall_size = round_up(sizeof(code_syscall), sizeof(long));
+static const int
+code_syscall_aligned = round_up(sizeof(code_syscall), sizeof(long));
 
 static inline __always_unused void __check_code_syscall(void)
 {
-	BUILD_BUG_ON(sizeof(code_syscall) != BUILTIN_SYSCALL_SIZE);
+	BUILD_BUG_ON(code_syscall_aligned != BUILTIN_SYSCALL_SIZE);
 	BUILD_BUG_ON(!is_log2(sizeof(code_syscall)));
 }
 
@@ -73,7 +74,7 @@ int syscall_seized(struct parasite_ctl *ctl, int nr, unsigned long *ret,
 	regs.ARM_r4 = arg5;
 	regs.ARM_r5 = arg6;
 
-	err = __parasite_execute_syscall(ctl, &regs);
+	err = __parasite_execute_syscall(ctl, &regs, code_syscall);
 
 	*ret = regs.ARM_r0;
 	return err;

criu/arch/arm/include/asm/parasite-syscall.h

@@ -5,10 +5,6 @@
 #define ARCH_SI_TRAP TRAP_BRKPT
 
 
-extern const char code_syscall[];
-extern const int code_syscall_size;
-
-
 void parasite_setup_regs(unsigned long new_ip, void *stack, user_regs_struct_t *regs);
 
 void *mmap_seized(struct parasite_ctl *ctl,

criu/arch/ppc64/crtools.c

@@ -32,8 +32,6 @@ const u32 code_syscall[] = {
 	0x0fe00000		/* twi 31,0,0	*/
 };
 
-const int code_syscall_size = sizeof(code_syscall);
-
 static inline void __check_code_syscall(void)
 {
 	BUILD_BUG_ON(sizeof(code_syscall) != BUILTIN_SYSCALL_SIZE);
@@ -80,7 +78,7 @@ int syscall_seized(struct parasite_ctl *ctl, int nr, unsigned long *ret,
 	regs.gpr[7] = arg5;
 	regs.gpr[8] = arg6;
 
-	err = __parasite_execute_syscall(ctl, &regs);
+	err = __parasite_execute_syscall(ctl, &regs, code_syscall);
 
 	*ret = regs.gpr[3];
 	return err;

criu/arch/ppc64/include/asm/parasite-syscall.h

@@ -5,9 +5,6 @@ struct parasite_ctl;
 
 #define ARCH_SI_TRAP TRAP_BRKPT
 
-extern const char code_syscall[];
-extern const int code_syscall_size;
-
 void parasite_setup_regs(unsigned long new_ip, void *stack, user_regs_struct_t *regs);
 
 void *mmap_seized(struct parasite_ctl *ctl,

criu/arch/x86/crtools.c

@@ -31,11 +31,12 @@ const char code_syscall[] = {
 	0xcc, 0xcc, 0xcc, 0xcc, 0xcc, 0xcc	/* int 3, ... */
 };
 
-const int code_syscall_size = round_up(sizeof(code_syscall), sizeof(long));
+static const int
+code_syscall_aligned = round_up(sizeof(code_syscall), sizeof(long));
 
 static inline __always_unused void __check_code_syscall(void)
 {
-	BUILD_BUG_ON(sizeof(code_syscall) != BUILTIN_SYSCALL_SIZE);
+	BUILD_BUG_ON(code_syscall_aligned != BUILTIN_SYSCALL_SIZE);
 	BUILD_BUG_ON(!is_log2(sizeof(code_syscall)));
 }
 
@@ -103,7 +104,7 @@ int syscall_seized(struct parasite_ctl *ctl, int nr, unsigned long *ret,
 	regs.r8  = arg5;
 	regs.r9  = arg6;
 
-	err = __parasite_execute_syscall(ctl, &regs);
+	err = __parasite_execute_syscall(ctl, &regs, code_syscall);
 
 	*ret = regs.ax;
 	return err;

criu/arch/x86/include/asm/parasite-syscall.h

@@ -8,9 +8,6 @@ struct parasite_ctl;
 #define ARCH_SI_TRAP SI_KERNEL
 
 
-extern const char code_syscall[];
-extern const int code_syscall_size;
-
 void parasite_setup_regs(unsigned long new_ip, void *stack, user_regs_struct_t *regs);
 
 void *mmap_seized(struct parasite_ctl *ctl,

criu/include/parasite-syscall.h

@@ -119,7 +119,7 @@ extern int syscall_seized(struct parasite_ctl *ctl, int nr, unsigned long *ret,
 			  unsigned long arg5, unsigned long arg6);
 
 extern int __parasite_execute_syscall(struct parasite_ctl *ctl,
-				user_regs_struct_t *regs);
+		user_regs_struct_t *regs, const char *code_syscall);
 extern bool arch_can_dump_task(pid_t pid);
 
 /*

criu/parasite-syscall.c

@@ -44,7 +44,7 @@
 static int can_run_syscall(unsigned long ip, unsigned long start,
 			   unsigned long end, unsigned long pad)
 {
-	return ip >= start && ip < (end - code_syscall_size - pad);
+	return ip >= start && ip < (end - BUILTIN_SYSCALL_SIZE - pad);
 }
 
 static int syscall_fits_vma_area(struct vma_area *vma_area, unsigned long pad)
@@ -210,7 +210,8 @@ err:
 	return ret;
 }
 
-int __parasite_execute_syscall(struct parasite_ctl *ctl, user_regs_struct_t *regs)
+int __parasite_execute_syscall(struct parasite_ctl *ctl,
+		user_regs_struct_t *regs, const char *code_syscall)
 {
 	pid_t pid = ctl->pid.real;
 	int err;