[PATCH v3 5/8] ftrace: Add swap_func to ftrace_process_locs()
Mike Rapoport <[email protected]>
| Newsgroups | gmane.linux.ports.ppc.embedded,gmane.linux.kernel.bpf,gmane.linux.ports.alpha,gmane.linux.kernel.cross-arch,gmane.linux.ports.arm.kernel,gmane.linux.ports.hexagon,gmane.linux.kernel,gmane.linux.ports.mips,gmane.linux.kernel.mm,gmane.linux.kernel.modules,gmane.linux.ports.parisc,gmane.linux.ports.riscv,gmane.linux.ports.sh.devel,gmane.linux.kernel.arc,gmane.linux.uml.devel,gmane.linux.ports.sparc |
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From: Song Liu <[email protected]> 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 <[email protected]> Signed-off-by: Mike Rapoport (Microsoft) <[email protected]> --- include/linux/ftrace.h | 2 ++ kernel/trace/ftrace.c | 19 ++++++++++++++++++- 2 files changed, 20 insertions(+), 1 deletion(-) diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index fd5e84d0ec47..b794dcb7cae8 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -1188,4 +1188,6 @@ 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 4c28dd177ca6..95bb9b52ab36 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -6989,6 +6989,23 @@ static void test_is_sorted(unsigned long *start, unsigned long count) } #endif +/* + * ftrace_process_locs sorts module mcount, which might be inside RO + * memory. + * ftrace_swap_func allows architectures to use RO-memory-poke function to + * do the sorting. + */ +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) @@ -7016,7 +7033,7 @@ 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