On Fri, 13 Nov 2020 10:34:14 -0800 Sami Tolvanen <[email protected]> wrote:
> my_tramp[12]? are declared as global functions in C, but they are not > marked global in the inline assembly definition. This mismatch confuses > Clang's Control-Flow Integrity checking. Fix the definitions by adding > .globl. > Actually, since that function is not really global, would it work if you removed the "extern" from the my_tramp declaration? In other words, is there a way to tell C that a function is declared in an inline assembly block? -- Steve > Signed-off-by: Sami Tolvanen <[email protected]> > --- > samples/ftrace/ftrace-direct-modify.c | 2 ++ > samples/ftrace/ftrace-direct-too.c | 1 + > samples/ftrace/ftrace-direct.c | 1 + > 3 files changed, 4 insertions(+) > > diff --git a/samples/ftrace/ftrace-direct-modify.c > b/samples/ftrace/ftrace-direct-modify.c > index c13a5bc5095b..5b9a09957c6e 100644 > --- a/samples/ftrace/ftrace-direct-modify.c > +++ b/samples/ftrace/ftrace-direct-modify.c > @@ -21,6 +21,7 @@ static unsigned long my_ip = (unsigned long)schedule; > asm ( > " .pushsection .text, \"ax\", @progbits\n" > " .type my_tramp1, @function\n" > +" .globl my_tramp1\n" > " my_tramp1:" > " pushq %rbp\n" > " movq %rsp, %rbp\n" > @@ -29,6 +30,7 @@ asm ( > " .size my_tramp1, .-my_tramp1\n" > " ret\n" > " .type my_tramp2, @function\n" > +" .globl my_tramp2\n" > " my_tramp2:" > " pushq %rbp\n" > " movq %rsp, %rbp\n" > diff --git a/samples/ftrace/ftrace-direct-too.c > b/samples/ftrace/ftrace-direct-too.c > index d5c5022be664..3f0079c9bd6f 100644 > --- a/samples/ftrace/ftrace-direct-too.c > +++ b/samples/ftrace/ftrace-direct-too.c > @@ -16,6 +16,7 @@ extern void my_tramp(void *); > asm ( > " .pushsection .text, \"ax\", @progbits\n" > " .type my_tramp, @function\n" > +" .globl my_tramp\n" > " my_tramp:" > " pushq %rbp\n" > " movq %rsp, %rbp\n" > diff --git a/samples/ftrace/ftrace-direct.c b/samples/ftrace/ftrace-direct.c > index 63ca06d42c80..a2729d1ef17f 100644 > --- a/samples/ftrace/ftrace-direct.c > +++ b/samples/ftrace/ftrace-direct.c > @@ -14,6 +14,7 @@ extern void my_tramp(void *); > asm ( > " .pushsection .text, \"ax\", @progbits\n" > " .type my_tramp, @function\n" > +" .globl my_tramp\n" > " my_tramp:" > " pushq %rbp\n" > " movq %rsp, %rbp\n" > > base-commit: 585e5b17b92dead8a3aca4e3c9876fbca5f7e0ba
