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authorSteven Rostedt (VMware) <rostedt@goodmis.org>2020-06-17 16:56:16 -0400
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2021-10-19 20:33:12 -0400
commit34cdd18b8d245f3e901e5325313c27de727ab80d (patch)
tree4ed5ee40076e2018161e568a980cd3885636b39c /include/asm-generic/vmlinux.lds.h
parentaffc659246293df42ba2d184c674cc959c05aa02 (diff)
downloadlwn-34cdd18b8d245f3e901e5325313c27de727ab80d.tar.gz
lwn-34cdd18b8d245f3e901e5325313c27de727ab80d.zip
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 <oscar.carter@gmx.com> Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'include/asm-generic/vmlinux.lds.h')
-rw-r--r--include/asm-generic/vmlinux.lds.h10
1 files changed, 8 insertions, 2 deletions
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