| Message ID | 20210401233216.2540591-17-samitolvanen@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add support for Clang CFI | expand |
On Thu, Apr 01, 2021 at 04:32:14PM -0700, Sami Tolvanen wrote: > With CONFIG_CFI_CLANG, the compiler replaces function pointers with > jump table addresses, which breaks dynamic ftrace as the address of > ftrace_call is replaced with the address of ftrace_call.cfi_jt. Use > function_nocfi() to get the address of the actual function instead. > > Suggested-by: Ben Dai <ben.dai@unisoc.com> > Signed-off-by: Sami Tolvanen <samitolvanen@google.com> > --- > arch/arm64/kernel/ftrace.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c > index 86a5cf9bc19a..b5d3ddaf69d9 100644 > --- a/arch/arm64/kernel/ftrace.c > +++ b/arch/arm64/kernel/ftrace.c > @@ -55,7 +55,7 @@ int ftrace_update_ftrace_func(ftrace_func_t func) > unsigned long pc; > u32 new; > > - pc = (unsigned long)&ftrace_call; > + pc = (unsigned long)function_nocfi(ftrace_call); Acked-by: Mark Rutland <mark.rutland@arm.com> Thanks, Mark. > new = aarch64_insn_gen_branch_imm(pc, (unsigned long)func, > AARCH64_INSN_BRANCH_LINK); > > -- > 2.31.0.208.g409f899ff0-goog >
diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c index 86a5cf9bc19a..b5d3ddaf69d9 100644 --- a/arch/arm64/kernel/ftrace.c +++ b/arch/arm64/kernel/ftrace.c @@ -55,7 +55,7 @@ int ftrace_update_ftrace_func(ftrace_func_t func) unsigned long pc; u32 new; - pc = (unsigned long)&ftrace_call; + pc = (unsigned long)function_nocfi(ftrace_call); new = aarch64_insn_gen_branch_imm(pc, (unsigned long)func, AARCH64_INSN_BRANCH_LINK);
With CONFIG_CFI_CLANG, the compiler replaces function pointers with jump table addresses, which breaks dynamic ftrace as the address of ftrace_call is replaced with the address of ftrace_call.cfi_jt. Use function_nocfi() to get the address of the actual function instead. Suggested-by: Ben Dai <ben.dai@unisoc.com> Signed-off-by: Sami Tolvanen <samitolvanen@google.com> --- arch/arm64/kernel/ftrace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)