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authorSteven Rostedt (VMware) <rostedt@goodmis.org>2019-10-15 09:00:55 -0400
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2019-11-14 13:13:43 -0500
commitb83b43ffc6e4b514ca034a0fbdee01322e2f7022 (patch)
tree8e8d830664e6faf98589f241bd0ccba44802f8c8 /arch/sh/boot
parent953ae45a0c25e09428d4a03d7654f97ab8a36647 (diff)
fgraph: Fix function type mismatches of ftrace_graph_return using ftrace_stub
The C compiler is allowing more checks to make sure that function pointers are assigned to the correct prototype function. Unfortunately, the function graph tracer uses a special name with its assigned ftrace_graph_return function pointer that maps to a stub function used by the function tracer (ftrace_stub). The ftrace_graph_return variable is compared to the ftrace_stub in some archs to know if the function graph tracer is enabled or not. This means we can not just simply create a new function stub that compares it without modifying all the archs. Instead, have the linker script create a function_graph_stub that maps to ftrace_stub, and this way we can define the prototype for it to match the prototype of ftrace_graph_return, and make the compiler checks all happy! Link: http://lkml.kernel.org/r/20191015090055.789a0aed@gandalf.local.home Cc: linux-sh@vger.kernel.org Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Rich Felker <dalias@libc.org> Reported-by: Sami Tolvanen <samitolvanen@google.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'arch/sh/boot')
-rw-r--r--arch/sh/boot/compressed/misc.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/sh/boot/compressed/misc.c b/arch/sh/boot/compressed/misc.c
index c15cac9251b9..e69ec12cbbe6 100644
--- a/arch/sh/boot/compressed/misc.c
+++ b/arch/sh/boot/compressed/misc.c
@@ -111,6 +111,11 @@ void __stack_chk_fail(void)
error("stack-protector: Kernel stack is corrupted\n");
}
+/* Needed because vmlinux.lds.h references this */
+void ftrace_stub(void)
+{
+}
+
#ifdef CONFIG_SUPERH64
#define stackalign 8
#else