lab1_syscall_patch_4.13.3

From 3c3820f88d5315af4c52b5f30d749c9d315fef61 Mon Sep 17 00:00:00 2001
From: student <student@ReliableEmbeddedSystems.com>
Date: Wed, 27 Sep 2017 07:34:41 -0500
Subject: [PATCH] introduce new syscall

Signed-off-by: student <student@ReliableEmbeddedSystems.com>
---
 arch/x86/entry/syscalls/syscall_32.tbl |  1 +
 arch/x86/entry/syscalls/syscall_64.tbl |  1 +
 kernel/sys.c                           | 19 +++++++++++++++++++
 3 files changed, 21 insertions(+)

diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index 448ac21..0a54704 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -391,3 +391,4 @@
 382	i386	pkey_free		sys_pkey_free
 383	i386	statx			sys_statx
 384	i386	arch_prctl		sys_arch_prctl			compat_sys_arch_prctl
+385     i386    my_syscall              sys_my_syscall
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index 5aef183..6ac6529 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -339,6 +339,7 @@
 330	common	pkey_alloc		sys_pkey_alloc
 331	common	pkey_free		sys_pkey_free
 332	common	statx			sys_statx
+333     common  my_syscall              sys_my_syscall

 #
 # x32-specific system call numbers start at 512 to avoid cache impact
diff --git a/kernel/sys.c b/kernel/sys.c
index 2855ee7..ab5d7ef 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -2552,3 +2552,22 @@ COMPAT_SYSCALL_DEFINE1(sysinfo, struct compat_sysinfo __user *, info)
 	return 0;
 }
 #endif /* CONFIG_COMPAT */
+
+
+/* Adding a dynamical system call */
+struct my_sc_struct {
+	long (*fun)(unsigned long p1);
+} my_sc = {
+	NULL};
+EXPORT_SYMBOL(my_sc);
+
+SYSCALL_DEFINE1(my_syscall, unsigned long, p1)
+{
+	struct my_sc_struct *s = (struct my_sc_struct *)&my_sc;
+
+	pr_info("Entering my_syscall with p1 = %ld at jiffies=%ld\n",
+		       p1, jiffies);
+	if (!s || !s->fun)
+               return -ENOSYS;
+	return s->fun(p1);
+}
--
2.11.0