cr: introduced the macro REG_SYSCALL_NR

The macro REG_SYSCALL_NR is designated to get the value of the CPU register
storing syscall number in a machine-independent way.
Signed-off-by: Alexander Kartashov <alekskartashov@parallels.com>
Acked-by: Andrew Vagin <avagin@parallels.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

arch/arm/include/asm/types.h

@@ -209,6 +209,7 @@ typedef struct {
 
 #define REG_RES(regs) ((regs).ARM_r0)
 #define REG_IP(regs)  ((regs).ARM_pc)
+#define REG_SYSCALL_NR(regs) ((regs).ARM_r7)
 
 #define TASK_SIZE 0xbf000000
 

arch/x86/include/asm/types.h

@@ -237,6 +237,7 @@ typedef uint64_t auxv_t;
 
 #define REG_RES(regs) ((regs).ax)
 #define REG_IP(regs)  ((regs).ip)
+#define REG_SYSCALL_NR(regs)	((regs).orig_ax)
 
 #define CORE_ENTRY__MARCH CORE_ENTRY__MARCH__X86_64
 

parasite-syscall.c

@@ -739,8 +739,8 @@ static int parasite_fini_seized(struct parasite_ctl *ctl)
 			return -1;
 		}
 
-		pr_debug("%d is going to execute the syscall %lx\n", pid, regs.orig_ax);
-		if (regs.orig_ax == __NR_rt_sigreturn) {
+		pr_debug("%d is going to execute the syscall %lx\n", pid, REG_SYSCALL_NR(regs));
+		if (REG_SYSCALL_NR(regs) == __NR_rt_sigreturn) {
 			pr_debug("%d was stopped\n", pid);
 			break;
 		}