Implement kexec_file_load syscall decoding

* xlat/kexec_file_load_flags.in: New file.
* kexec.c: Include "xlat/kexec_file_load_flags.h".
(SYS_FUNC(kexec_file_load)): New function.
* linux/dummy.h (sys_kexec_file_load): Remove stub alias.
* pathtrace.c (pathtrace_match): Add SEN_kexec_file_load.

kexec.c

@@ -79,3 +79,24 @@ SYS_FUNC(kexec_load)
 
 	return RVAL_DECODED;
 }
+
+#include "xlat/kexec_file_load_flags.h"
+
+SYS_FUNC(kexec_file_load)
+{
+	/* kernel_fd */
+	printfd(tcp, tcp->u_arg[0]);
+	tprints(", ");
+	/* initrd_fd */
+	printfd(tcp, tcp->u_arg[1]);
+	tprints(", ");
+	/* cmdline_len */
+	tprintf("%lu, ", tcp->u_arg[2]);
+	/* cmdline */
+	printstr(tcp, tcp->u_arg[3], tcp->u_arg[2]);
+	tprints(", ");
+	/* flags */
+	printflags(kexec_file_load_flags, tcp->u_arg[4], "KEXEC_FILE_???");
+
+	return RVAL_DECODED;
+}

linux/dummy.h

@@ -32,7 +32,6 @@
 #endif
 
 /* still unfinished */
-#define	sys_kexec_file_load	printargs
 #define	sys_lookup_dcookie	printargs
 #define	sys_name_to_handle_at	printargs
 #define	sys_open_by_handle_at	printargs

pathtrace.c

@@ -163,6 +163,7 @@ pathtrace_match(struct tcb *tcp)
 	switch (s->sen) {
 	case SEN_dup2:
 	case SEN_dup3:
+	case SEN_kexec_file_load:
 	case SEN_sendfile:
 	case SEN_sendfile64:
 	case SEN_tee:

xlat/kexec_file_load_flags.in

@@ -0,0 +1,3 @@
+KEXEC_FILE_UNLOAD	1
+KEXEC_FILE_ON_CRASH	2
+KEXEC_FILE_NO_INITRAMFS	4