powerpc/ptrace: replace ptrace_report_syscall() with a tracehook call

Arch code should use tracehook_*() helpers, as documented in
include/linux/tracehook.h, ptrace_report_syscall() is not expected to
be used outside that file.

The patch does not look very nice, but at least it is correct
and opens the way for PTRACE_GET_SYSCALL_INFO API.

Co-authored-by: Dmitry V. Levin <ldv@altlinux.org>
Fixes: 5521eb4bca2d ("powerpc/ptrace: Add support for PTRACE_SYSEMU")
Signed-off-by: Elvira Khabirova <lineprinter@altlinux.org>
Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
[mpe: Take this as a minimal fix for 4.20, we'll rework it later]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
index afb819f4ca68bee0f88fab357ffe9395508dc106..714c3480c52dcca8761a9d9e2a24e9eaad0a6256 100644 (file)
--- a/arch/powerpc/kernel/ptrace.c
+++ b/arch/powerpc/kernel/ptrace.c
@@ -3266,12 +3266,17 @@ long do_syscall_trace_enter(struct pt_regs *regs)
        user_exit();
 
        if (test_thread_flag(TIF_SYSCALL_EMU)) {
-               ptrace_report_syscall(regs);
                /*
+                * A nonzero return code from tracehook_report_syscall_entry()
+                * tells us to prevent the syscall execution, but we are not
+                * going to execute it anyway.
+                *
                 * Returning -1 will skip the syscall execution. We want to
                 * avoid clobbering any register also, thus, not 'gotoing'
                 * skip label.
                 */
+               if (tracehook_report_syscall_entry(regs))
+                       ;
                return -1;
        }