powerpc/livepatch: return -ERRNO values in save_stack_trace_tsk_reliable()

To match its x86 counterpart, save_stack_trace_tsk_reliable() should
return -EINVAL in cases that it is currently returning 1.  No caller is
currently differentiating non-zero error codes, but let's keep the
arch-specific implementations consistent.

Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/kernel/stacktrace.c b/arch/powerpc/kernel/stacktrace.c
index 28c3c25..cf31ce6 100644 (file)
--- a/arch/powerpc/kernel/stacktrace.c
+++ b/arch/powerpc/kernel/stacktrace.c
@@ -133,7 +133,7 @@ save_stack_trace_tsk_reliable(struct task_struct *tsk,
 
        if (sp < stack_page + sizeof(struct thread_struct) ||
            sp > stack_end - STACK_FRAME_MIN_SIZE) {
-               return 1;
+               return -EINVAL;
        }
 
        for (firstframe = true; sp != stack_end;
@@ -143,16 +143,16 @@ save_stack_trace_tsk_reliable(struct task_struct *tsk,
 
                /* sanity check: ABI requires SP to be aligned 16 bytes. */
                if (sp & 0xF)
-                       return 1;
+                       return -EINVAL;
 
                newsp = stack[0];
                /* Stack grows downwards; unwinder may only go up. */
                if (newsp <= sp)
-                       return 1;
+                       return -EINVAL;
 
                if (newsp != stack_end &&
                    newsp > stack_end - STACK_FRAME_MIN_SIZE) {
-                       return 1; /* invalid backlink, too far up. */
+                       return -EINVAL; /* invalid backlink, too far up. */
                }
 
                /*
@@ -166,13 +166,13 @@ save_stack_trace_tsk_reliable(struct task_struct *tsk,
                /* Mark stacktraces with exception frames as unreliable. */
                if (sp <= stack_end - STACK_INT_FRAME_SIZE &&
                    stack[STACK_FRAME_MARKER] == STACK_FRAME_REGS_MARKER) {
-                       return 1;
+                       return -EINVAL;
                }
 
                /* Examine the saved LR: it must point into kernel code. */
                ip = stack[STACK_FRAME_LR_SAVE];
                if (!__kernel_text_address(ip))
-                       return 1;
+                       return -EINVAL;
 
                /*
                 * FIXME: IMHO these tests do not belong in
@@ -185,7 +185,7 @@ save_stack_trace_tsk_reliable(struct task_struct *tsk,
                 * as unreliable.
                 */
                if (ip == (unsigned long)kretprobe_trampoline)
-                       return 1;
+                       return -EINVAL;
 #endif
 
                if (trace->nr_entries >= trace->max_entries)