[PATCH v3 8/8] x86/ftrace: enable EXECMEM_ROX_CACHE for ftrace allocations
From: Mike Rapoport <rppt@kernel.org>
Date: 2025-07-13 07:18:30
Also in:
linux-mm, linux-modules, lkml
Subsystem:
function hooks (ftrace), the rest, x86 architecture (32-bit and 64-bit), x86 mm · Maintainers:
Steven Rostedt, Masami Hiramatsu, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, Andy Lutomirski, Peter Zijlstra
From: "Mike Rapoport (Microsoft)" <rppt@kernel.org> For the most part ftrace uses text poking and can handle ROX memory. The only place that requires writable memory is create_trampoline() that updates the allocated memory and in the end makes it ROX. Use execmem_alloc_rw() in x86::ftrace::alloc_tramp() and enable ROX cache for EXECMEM_FTRACE when configuration and CPU features allow that. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org> --- arch/x86/kernel/ftrace.c | 2 +- arch/x86/mm/init.c | 9 ++++++++- 2 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 252e82bcfd2f..4450acec9390 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c@@ -263,7 +263,7 @@ void arch_ftrace_update_code(int command) static inline void *alloc_tramp(unsigned long size) { - return execmem_alloc(EXECMEM_FTRACE, size); + return execmem_alloc_rw(EXECMEM_FTRACE, size); } static inline void tramp_free(void *tramp) {
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index 442fafd8ff52..bb57e93b4caf 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c@@ -1105,7 +1105,14 @@ struct execmem_info __init *execmem_arch_setup(void) .pgprot = PAGE_KERNEL_ROX, .alignment = MODULE_ALIGN, }, - [EXECMEM_FTRACE ... EXECMEM_BPF] = { + [EXECMEM_FTRACE] = { + .flags = flags, + .start = start, + .end = MODULES_END, + .pgprot = pgprot, + .alignment = MODULE_ALIGN, + }, + [EXECMEM_BPF] = { .flags = EXECMEM_KASAN_SHADOW, .start = start, .end = MODULES_END,
--
2.47.2