Re: [PATCH v22 19/20] ftrace: Add ftrace_get_symaddr to convert fentry_ip to symaddr
From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Date: 2025-02-04 09:19:05
Also in:
bpf, linux-arch, lkml
Subsystem:
function hooks (ftrace), the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Steven Rostedt, Masami Hiramatsu, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
On Mon, 3 Feb 2025 22:33:48 +0100 Gabriel de Perthuis [off-list ref] wrote:
Hello, I got errors building Linux 6.14-rc1 that were solved by reverting this patch and the one after (19/20 and 20/20). Errors look like: In file included from ./arch/x86/include/asm/asm-prototypes.h:2, from <stdin>:3: ./arch/x86/include/asm/ftrace.h: In function 'arch_ftrace_get_symaddr': ./arch/x86/include/asm/ftrace.h:46:21: error: implicit declaration of function 'get_kernel_nofault' [-Wimplicit-function-declaration] 46 | if (get_kernel_nofault(instr, (u32 *)(fentry_ip - ENDBR_INSN_SIZE))) | ^~~~~~~~~~~~~~~~~~ Will send .config on request if needed.
Thanks for the report! -------<arch/x86/include/asm/asm-prototypes.h> /* SPDX-License-Identifier: GPL-2.0 */ #include <asm/ftrace.h> #include <linux/uaccess.h> ----- Ah, that's why... get_kernel_nofault() is defined in linux/uaccess.h. I also found that is_endbr() is in asm/ibt.h. Can you try this? Thank you,
diff --git a/arch/x86/include/asm/ftrace.h b/arch/x86/include/asm/ftrace.h
index f9cb4d07df58..d24d7c71253f 100644
--- a/arch/x86/include/asm/ftrace.h
+++ b/arch/x86/include/asm/ftrace.h@@ -16,24 +16,9 @@ # include <asm/ibt.h> /* Add offset for endbr64 if IBT enabled */ # define FTRACE_MCOUNT_MAX_OFFSET ENDBR_INSN_SIZE -#endif - -#ifdef CONFIG_DYNAMIC_FTRACE -#define ARCH_SUPPORTS_FTRACE_OPS 1 -#endif - -#ifndef __ASSEMBLY__ -extern void __fentry__(void); - -static inline unsigned long ftrace_call_adjust(unsigned long addr) -{ - /* - * addr is the address of the mcount call instruction. - * recordmcount does the necessary offset calculation. - */ - return addr; -} +#include <linux/uaccess.h> +/* This only supports fentry based ftrace. */ static inline unsigned long arch_ftrace_get_symaddr(unsigned long fentry_ip) { #ifdef CONFIG_X86_KERNEL_IBT
@@ -55,6 +40,24 @@ static inline unsigned long arch_ftrace_get_symaddr(unsigned long fentry_ip) } #define ftrace_get_symaddr(fentry_ip) arch_ftrace_get_symaddr(fentry_ip) +#endif + +#ifdef CONFIG_DYNAMIC_FTRACE +#define ARCH_SUPPORTS_FTRACE_OPS 1 +#endif + +#ifndef __ASSEMBLY__ +extern void __fentry__(void); + +static inline unsigned long ftrace_call_adjust(unsigned long addr) +{ + /* + * addr is the address of the mcount call instruction. + * recordmcount does the necessary offset calculation. + */ + return addr; +} + #ifdef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS #include <linux/ftrace_regs.h>
--
Masami Hiramatsu (Google) <mhiramat@kernel.org>