parisc: Fix and enable seccomp filter support

The seccomp filter support requires careful handling of task registers.  This
includes reloading of the return value (%r28) and proper syscall exit if
secure_computing() returned -1.

Additionally we need to sign-extend the syscall number from signed 32bit to
signed 64bit in do_syscall_trace_enter() since the ptrace interface only allows
storing 32bit values in compat mode.

Signed-off-by: Helge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org # v4.5

1 files changed, 13 insertions, 0 deletions

diff --git a/arch/parisc/include/asm/syscall.h b/arch/parisc/include/asm/syscall.h
index a5eba95d87fe..637ce8d6f375 100644
--- a/arch/parisc/include/asm/syscall.h
+++ b/arch/parisc/include/asm/syscall.h
@@ -39,6 +39,19 @@ static inline void syscall_get_arguments(struct task_struct *tsk,
         }
 }
 
+static inline void syscall_set_return_value(struct task_struct *task,
+                                            struct pt_regs *regs,
+                                            int error, long val)
+{
+        regs->gr[28] = error ? error : val;
+}
+
+static inline void syscall_rollback(struct task_struct *task,
+                                    struct pt_regs *regs)
+{
+        /* do nothing */
+}
+
 static inline int syscall_get_arch(void)
 {
         int arch = AUDIT_ARCH_PARISC;