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authorMickaël Salaün <mic@digikod.net>2015-12-29 23:35:46 +0300
committerRichard Weinberger <richard@nod.at>2016-01-10 23:49:49 +0300
commitd8f8b8445648c267a24f30a72533e77cb6543f21 (patch)
tree771077fdccf7ec1b8b1f09324210867796a52dcd /arch/um
parent4a0b88070406323487bad730d8945f482151a145 (diff)
downloadlinux-d8f8b8445648c267a24f30a72533e77cb6543f21.tar.xz
um: Add full asm/syscall.h support
Add subarchitecture-independent implementation of asm-generic/syscall.h allowing access to user system call parameters and results: * syscall_get_nr() * syscall_rollback() * syscall_get_error() * syscall_get_return_value() * syscall_set_return_value() * syscall_get_arguments() * syscall_set_arguments() * syscall_get_arch() provided by arch/x86/um/asm/syscall.h This provides the necessary syscall helpers needed by HAVE_ARCH_SECCOMP_FILTER plus syscall_get_error(). This is inspired from Meredydd Luff's patch (https://gerrit.chromium.org/gerrit/21425). Signed-off-by: Mickaël Salaün <mic@digikod.net> Cc: Jeff Dike <jdike@addtoit.com> Cc: Richard Weinberger <richard@nod.at> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Will Drewry <wad@chromium.org> Cc: Meredydd Luff <meredydd@senatehouse.org> Cc: David Drysdale <drysdale@google.com> Signed-off-by: Richard Weinberger <richard@nod.at> Acked-by: Kees Cook <keescook@chromium.org>
Diffstat (limited to 'arch/um')
-rw-r--r--arch/um/include/asm/syscall-generic.h138
1 files changed, 138 insertions, 0 deletions
diff --git a/arch/um/include/asm/syscall-generic.h b/arch/um/include/asm/syscall-generic.h
new file mode 100644
index 000000000000..9fb9cf8cd39a
--- /dev/null
+++ b/arch/um/include/asm/syscall-generic.h
@@ -0,0 +1,138 @@
+/*
+ * Access to user system call parameters and results
+ *
+ * See asm-generic/syscall.h for function descriptions.
+ *
+ * Copyright (C) 2015 Mickaël Salaün <mic@digikod.net>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef __UM_SYSCALL_GENERIC_H
+#define __UM_SYSCALL_GENERIC_H
+
+#include <asm/ptrace.h>
+#include <linux/err.h>
+#include <linux/sched.h>
+#include <sysdep/ptrace.h>
+
+static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
+{
+
+ return PT_REGS_SYSCALL_NR(regs);
+}
+
+static inline void syscall_rollback(struct task_struct *task,
+ struct pt_regs *regs)
+{
+ /* do nothing */
+}
+
+static inline long syscall_get_error(struct task_struct *task,
+ struct pt_regs *regs)
+{
+ const long error = regs_return_value(regs);
+
+ return IS_ERR_VALUE(error) ? error : 0;
+}
+
+static inline long syscall_get_return_value(struct task_struct *task,
+ struct pt_regs *regs)
+{
+ return regs_return_value(regs);
+}
+
+static inline void syscall_set_return_value(struct task_struct *task,
+ struct pt_regs *regs,
+ int error, long val)
+{
+ PT_REGS_SET_SYSCALL_RETURN(regs, (long) error ?: val);
+}
+
+static inline void syscall_get_arguments(struct task_struct *task,
+ struct pt_regs *regs,
+ unsigned int i, unsigned int n,
+ unsigned long *args)
+{
+ const struct uml_pt_regs *r = &regs->regs;
+
+ switch (i) {
+ case 0:
+ if (!n--)
+ break;
+ *args++ = UPT_SYSCALL_ARG1(r);
+ case 1:
+ if (!n--)
+ break;
+ *args++ = UPT_SYSCALL_ARG2(r);
+ case 2:
+ if (!n--)
+ break;
+ *args++ = UPT_SYSCALL_ARG3(r);
+ case 3:
+ if (!n--)
+ break;
+ *args++ = UPT_SYSCALL_ARG4(r);
+ case 4:
+ if (!n--)
+ break;
+ *args++ = UPT_SYSCALL_ARG5(r);
+ case 5:
+ if (!n--)
+ break;
+ *args++ = UPT_SYSCALL_ARG6(r);
+ case 6:
+ if (!n--)
+ break;
+ default:
+ BUG();
+ break;
+ }
+}
+
+static inline void syscall_set_arguments(struct task_struct *task,
+ struct pt_regs *regs,
+ unsigned int i, unsigned int n,
+ const unsigned long *args)
+{
+ struct uml_pt_regs *r = &regs->regs;
+
+ switch (i) {
+ case 0:
+ if (!n--)
+ break;
+ UPT_SYSCALL_ARG1(r) = *args++;
+ case 1:
+ if (!n--)
+ break;
+ UPT_SYSCALL_ARG2(r) = *args++;
+ case 2:
+ if (!n--)
+ break;
+ UPT_SYSCALL_ARG3(r) = *args++;
+ case 3:
+ if (!n--)
+ break;
+ UPT_SYSCALL_ARG4(r) = *args++;
+ case 4:
+ if (!n--)
+ break;
+ UPT_SYSCALL_ARG5(r) = *args++;
+ case 5:
+ if (!n--)
+ break;
+ UPT_SYSCALL_ARG6(r) = *args++;
+ case 6:
+ if (!n--)
+ break;
+ default:
+ BUG();
+ break;
+ }
+}
+
+/* See arch/x86/um/asm/syscall.h for syscall_get_arch() definition. */
+
+#endif /* __UM_SYSCALL_GENERIC_H */