From: Peter Zijlstra <peterz@infradead.org>
To: Steven Rostedt <rostedt@goodmis.org>,
x86@kernel.org, linux-kernel@vger.kernel.org,
Mark Rutland <mark.rutland@arm.com>
Cc: Kees Cook <keescook@chromium.org>,
Sami Tolvanen <samitolvanen@google.com>
Subject: Re: [PATCH] ftrace,kcfi: Separate ftrace_stub() and ftrace_stub_graph()
Date: Tue, 18 Oct 2022 14:36:53 +0200 [thread overview]
Message-ID: <Y06d5X39EmKVamLN@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <Y06dg4e1xF6JTdQq@hirez.programming.kicks-ass.net>
On Tue, Oct 18, 2022 at 02:35:16PM +0200, Peter Zijlstra wrote:
>
> Different function signatures means they needs to be different
> functions; otherwise CFI gets upset.
>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> ---
>
> Notable; this patch depends on eac828eaef29 ("x86/ftrace: Remove
> ftrace_epilogue()") which can be cleanly picked on top of -rc1.
>
> Since kCFI is upstream this should go into some /urgent tree.
Combined (eac828eaef29 + this patch) generate a conflict against
tip/x86/core. Resolution looks like:
diff --cc arch/x86/kernel/ftrace_64.S
index 2a4be92fd144,6a7e6d666a12..000000000000
--- a/arch/x86/kernel/ftrace_64.S
+++ b/arch/x86/kernel/ftrace_64.S
@@@ -4,7 -4,7 +4,8 @@@
*/
#include <linux/linkage.h>
+#include <linux/cfi_types.h>
+ #include <asm/asm-offsets.h>
#include <asm/ptrace.h>
#include <asm/ftrace.h>
#include <asm/export.h>
@@@ -130,14 -130,6 +131,16 @@@
.endm
+SYM_TYPED_FUNC_START(ftrace_stub)
++ CALL_DEPTH_ACCOUNT
+ RET
+SYM_FUNC_END(ftrace_stub)
+
+SYM_TYPED_FUNC_START(ftrace_stub_graph)
++ CALL_DEPTH_ACCOUNT
+ RET
+SYM_FUNC_END(ftrace_stub_graph)
+
#ifdef CONFIG_DYNAMIC_FTRACE
SYM_FUNC_START(__fentry__)
@@@ -284,8 -305,13 +311,10 @@@ STACK_FRAME_NON_STANDARD_FP(ftrace_regs
#else /* ! CONFIG_DYNAMIC_FTRACE */
SYM_FUNC_START(__fentry__)
+ CALL_DEPTH_ACCOUNT
+
cmpq $ftrace_stub, ftrace_trace_function
jnz trace
-
-SYM_INNER_LABEL(ftrace_stub, SYM_L_GLOBAL)
- ENDBR
RET
trace:
next prev parent reply other threads:[~2022-10-18 12:37 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-18 12:35 [PATCH] ftrace,kcfi: Separate ftrace_stub() and ftrace_stub_graph() Peter Zijlstra
2022-10-18 12:36 ` Peter Zijlstra [this message]
2022-10-18 13:18 ` Peter Zijlstra
2022-10-18 13:26 ` Mark Rutland
2022-10-18 14:28 ` Kees Cook
2022-10-18 15:00 ` Peter Zijlstra
2022-10-18 18:22 ` Kees Cook
2022-10-18 14:21 ` Steven Rostedt
2022-10-18 15:02 ` Peter Zijlstra
2022-10-20 15:17 ` [tip: x86/urgent] " tip-bot2 for Peter Zijlstra
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