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

parport0 · ldv-alt · mpe · commit a225f1567405 · 2018-12-10T15:19:58.000+11:00
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: 5521eb4 ("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
@@ -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;
 	}
 
