Messages in this thread Patch in this message | | | From | Wang Nan <> | Subject | [RFC PATCH v4 21/34] ftrace: sort ftrace entries earlier. | Date | Mon, 2 Mar 2015 22:24:59 +0800 |
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By extracting mcount sorting code and sort them earliler, futher patches will be able to determine whether an address is on an ftrace entry or not using bsearch().
ftrace_sort_mcount_area() will be called before, during and after ftrace_init (when module insertion). Ensure it sort kernel mcount table only once.
Signed-off-by: Wang Nan <wangnan0@huawei.com> --- include/linux/ftrace.h | 2 ++ init/main.c | 1 + kernel/trace/ftrace.c | 38 ++++++++++++++++++++++++++++++++++++-- 3 files changed, 39 insertions(+), 2 deletions(-)
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 1da6029..8db315a 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -701,8 +701,10 @@ static inline void __ftrace_enabled_restore(int enabled) #ifdef CONFIG_FTRACE_MCOUNT_RECORD extern void ftrace_init(void); +extern void ftrace_init_early(void); #else static inline void ftrace_init(void) { } +static inline void ftrace_init_early(void) { } #endif /* diff --git a/init/main.c b/init/main.c index 679d49e..6d269ac 100644 --- a/init/main.c +++ b/init/main.c @@ -518,6 +518,7 @@ asmlinkage __visible void __init start_kernel(void) boot_cpu_init(); page_address_init(); pr_notice("%s", linux_banner); + ftrace_init_early(); setup_arch(&command_line); init_kprobes_early(); mm_init_cpumask(&init_mm); diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 6c6cbb1..fa3cdd3 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -112,6 +112,7 @@ ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub; ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub; static struct ftrace_ops global_ops; static struct ftrace_ops control_ops; +static bool kernel_mcount_sorted = false; static void ftrace_ops_recurs_func(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *op, struct pt_regs *regs); @@ -4743,6 +4744,32 @@ static void ftrace_swap_ips(void *a, void *b, int size) *ipb = t; } +static void ftrace_sort_mcount_area(unsigned long *start, unsigned long *end) +{ + extern unsigned long __start_mcount_loc[]; + extern unsigned long __stop_mcount_loc[]; + + unsigned long count; + bool is_kernel_mcount; + + count = end - start; + if (!count) + return; + + is_kernel_mcount = + (start == __start_mcount_loc) && + (end == __stop_mcount_loc); + + if (is_kernel_mcount && kernel_mcount_sorted) + return; + + sort(start, count, sizeof(*start), + ftrace_cmp_ips, ftrace_swap_ips); + + if (is_kernel_mcount) + kernel_mcount_sorted = true; +} + static int ftrace_process_locs(struct module *mod, unsigned long *start, unsigned long *end) @@ -4761,8 +4788,7 @@ static int ftrace_process_locs(struct module *mod, if (!count) return 0; - sort(start, count, sizeof(*start), - ftrace_cmp_ips, ftrace_swap_ips); + ftrace_sort_mcount_area(start, end); start_pg = ftrace_allocate_pages(count); if (!start_pg) @@ -4965,6 +4991,14 @@ void __init ftrace_init(void) ftrace_disabled = 1; } +void __init ftrace_init_early(void) +{ + extern unsigned long __start_mcount_loc[]; + extern unsigned long __stop_mcount_loc[]; + + ftrace_sort_mcount_area(__start_mcount_loc, __stop_mcount_loc); +} + /* Do nothing if arch does not support this */ void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops) { -- 1.8.4
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