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-rw-r--r--arch/um/kernel/skas/syscall.c50
1 files changed, 50 insertions, 0 deletions
diff --git a/arch/um/kernel/skas/syscall.c b/arch/um/kernel/skas/syscall.c
new file mode 100644
index 000000000..9ee19e566
--- /dev/null
+++ b/arch/um/kernel/skas/syscall.c
@@ -0,0 +1,50 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
+ */
+
+#include <linux/kernel.h>
+#include <linux/ptrace.h>
+#include <linux/seccomp.h>
+#include <kern_util.h>
+#include <sysdep/ptrace.h>
+#include <sysdep/ptrace_user.h>
+#include <sysdep/syscalls.h>
+#include <linux/time-internal.h>
+#include <asm/unistd.h>
+
+void handle_syscall(struct uml_pt_regs *r)
+{
+ struct pt_regs *regs = container_of(r, struct pt_regs, regs);
+ int syscall;
+
+ /*
+ * If we have infinite CPU resources, then make every syscall also a
+ * preemption point, since we don't have any other preemption in this
+ * case, and kernel threads would basically never run until userspace
+ * went to sleep, even if said userspace interacts with the kernel in
+ * various ways.
+ */
+ if (time_travel_mode == TT_MODE_INFCPU ||
+ time_travel_mode == TT_MODE_EXTERNAL)
+ schedule();
+
+ /* Initialize the syscall number and default return value. */
+ UPT_SYSCALL_NR(r) = PT_SYSCALL_NR(r->gp);
+ PT_REGS_SET_SYSCALL_RETURN(regs, -ENOSYS);
+
+ if (syscall_trace_enter(regs))
+ goto out;
+
+ /* Do the seccomp check after ptrace; failures should be fast. */
+ if (secure_computing() == -1)
+ goto out;
+
+ syscall = UPT_SYSCALL_NR(r);
+ if (syscall >= 0 && syscall < __NR_syscalls)
+ PT_REGS_SET_SYSCALL_RETURN(regs,
+ EXECUTE_SYSCALL(syscall, regs));
+
+out:
+ syscall_trace_leave(regs);
+}