From 34cdd18b8d245f3e901e5325313c27de727ab80d Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Wed, 17 Jun 2020 16:56:16 -0400 Subject: tracing: Use linker magic instead of recasting ftrace_ops_list_func() In an effort to enable -Wcast-function-type in the top-level Makefile to support Control Flow Integrity builds, all function casts need to be removed. This means that ftrace_ops_list_func() can no longer be defined as ftrace_ops_no_ops(). The reason for ftrace_ops_no_ops() is to use that when an architecture calls ftrace_ops_list_func() with only two parameters (called from assembly). And to make sure there's no C side-effects, those archs call ftrace_ops_no_ops() which only has two parameters, as ftrace_ops_list_func() has four parameters. Instead of a typecast, use vmlinux.lds.h to define ftrace_ops_list_func() to arch_ftrace_ops_list_func() that will define the proper set of parameters. Link: https://lore.kernel.org/r/20200614070154.6039-1-oscar.carter@gmx.com Link: https://lkml.kernel.org/r/20200617165616.52241bde@oasis.local.home Link: https://lore.kernel.org/all/20211005053922.GA702049@embeddedor/ Requested-by: Oscar Carter Reported-by: kernel test robot Signed-off-by: Steven Rostedt (VMware) --- include/asm-generic/vmlinux.lds.h | 10 ++++++++-- include/linux/ftrace.h | 12 ++++++++++-- 2 files changed, 18 insertions(+), 4 deletions(-) (limited to 'include') diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index f2984af2b85b..8771c435f34b 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -164,16 +164,22 @@ * Need to also make ftrace_stub_graph point to ftrace_stub * so that the same stub location may have different protocols * and not mess up with C verifiers. + * + * ftrace_ops_list_func will be defined as arch_ftrace_ops_list_func + * as some archs will have a different prototype for that function + * but ftrace_ops_list_func() will have a single prototype. */ #define MCOUNT_REC() . = ALIGN(8); \ __start_mcount_loc = .; \ KEEP(*(__mcount_loc)) \ KEEP(*(__patchable_function_entries)) \ __stop_mcount_loc = .; \ - ftrace_stub_graph = ftrace_stub; + ftrace_stub_graph = ftrace_stub; \ + ftrace_ops_list_func = arch_ftrace_ops_list_func; #else # ifdef CONFIG_FUNCTION_TRACER -# define MCOUNT_REC() ftrace_stub_graph = ftrace_stub; +# define MCOUNT_REC() ftrace_stub_graph = ftrace_stub; \ + ftrace_ops_list_func = arch_ftrace_ops_list_func; # else # define MCOUNT_REC() # endif diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 832e65f06754..12fcfa2d23ea 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -30,16 +30,26 @@ #define ARCH_SUPPORTS_FTRACE_OPS 0 #endif +#ifdef CONFIG_FUNCTION_TRACER +struct ftrace_ops; +struct ftrace_regs; /* * If the arch's mcount caller does not support all of ftrace's * features, then it must call an indirect function that * does. Or at least does enough to prevent any unwelcome side effects. + * + * Also define the function prototype that these architectures use + * to call the ftrace_ops_list_func(). */ #if !ARCH_SUPPORTS_FTRACE_OPS # define FTRACE_FORCE_LIST_FUNC 1 +void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip); #else # define FTRACE_FORCE_LIST_FUNC 0 +void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip, + struct ftrace_ops *op, struct ftrace_regs *fregs); #endif +#endif /* CONFIG_FUNCTION_TRACER */ /* Main tracing buffer and events set up */ #ifdef CONFIG_TRACING @@ -88,8 +98,6 @@ extern int ftrace_enable_sysctl(struct ctl_table *table, int write, void *buffer, size_t *lenp, loff_t *ppos); -struct ftrace_ops; - #ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS struct ftrace_regs { -- cgit v1.2.3