[RFC PATCH 4/7] ftrace: Add swap_func to ftrace_process_locs()
From: Mike Rapoport <rppt@kernel.org>
Date: 2024-04-11 16:06:17
Also in:
bpf, linux-arch, linux-arm-kernel, linux-mm, linux-modules, linux-riscv, linux-trace-kernel, lkml
Subsystem:
function hooks (ftrace), the rest, tracing · Maintainers:
Steven Rostedt, Masami Hiramatsu, Linus Torvalds
From: Song Liu <song@kernel.org> ftrace_process_locs sorts module mcount, which is inside RO memory. Add a ftrace_swap_func so that archs can use RO-memory-poke function to do the sorting. Signed-off-by: Song Liu <song@kernel.org> Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org> --- include/linux/ftrace.h | 2 ++ kernel/trace/ftrace.c | 13 ++++++++++++- 2 files changed, 14 insertions(+), 1 deletion(-)
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 54d53f345d14..54393ce57f08 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h@@ -1172,4 +1172,6 @@ unsigned long arch_syscall_addr(int nr); #endif /* CONFIG_FTRACE_SYSCALLS */ +void ftrace_swap_func(void *a, void *b, int n); + #endif /* _LINUX_FTRACE_H */
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index da1710499698..95f11c8cdc5e 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c@@ -6480,6 +6480,17 @@ static void test_is_sorted(unsigned long *start, unsigned long count) } #endif +void __weak ftrace_swap_func(void *a, void *b, int n) +{ + unsigned long t; + + WARN_ON_ONCE(n != sizeof(t)); + + t = *((unsigned long *)a); + *(unsigned long *)a = *(unsigned long *)b; + *(unsigned long *)b = t; +} + static int ftrace_process_locs(struct module *mod, unsigned long *start, unsigned long *end)
@@ -6507,7 +6518,7 @@ static int ftrace_process_locs(struct module *mod, */ if (!IS_ENABLED(CONFIG_BUILDTIME_MCOUNT_SORT) || mod) { sort(start, count, sizeof(*start), - ftrace_cmp_ips, NULL); + ftrace_cmp_ips, ftrace_swap_func); } else { test_is_sorted(start, count); }
--
2.43.0