[PATCH v6 16/18] arm64: ftrace: use function_nocfi for ftrace_call
From: Sami Tolvanen <samitolvanen@google.com>
Date: 2021-04-08 18:30:50
Also in:
bpf, linux-arch, linux-hardening, linux-kbuild, linux-pci, lkml
Subsystem:
arm64 port (aarch64 architecture), function hooks (ftrace), the rest · Maintainers:
Catalin Marinas, Will Deacon, Steven Rostedt, Masami Hiramatsu, Linus Torvalds
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 <redacted> Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Acked-by: Mark Rutland <mark.rutland@arm.com> Tested-by: Nathan Chancellor <nathan@kernel.org> --- 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); new = aarch64_insn_gen_branch_imm(pc, (unsigned long)func, AARCH64_INSN_BRANCH_LINK);
--
2.31.1.295.g9ea45b61b8-goog
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