diff options
Diffstat (limited to 'arch/arm/kernel/ftrace.c')
-rw-r--r-- | arch/arm/kernel/ftrace.c | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/arch/arm/kernel/ftrace.c b/arch/arm/kernel/ftrace.c index 34e56647dcee..38b670cea08c 100644 --- a/arch/arm/kernel/ftrace.c +++ b/arch/arm/kernel/ftrace.c @@ -14,6 +14,7 @@ #include <linux/ftrace.h> #include <linux/uaccess.h> +#include <linux/stop_machine.h> #include <asm/cacheflush.h> #include <asm/opcodes.h> @@ -156,6 +157,39 @@ int ftrace_make_nop(struct module *mod, return ret; } +struct afmc_data { + int command; + atomic_t cpu; + atomic_t done; +}; + +static int __arch_ftrace_modify_code(void *data) +{ + struct afmc_data *afmcd = data; + + if (atomic_inc_return(&afmcd->cpu) == num_online_cpus()) { + /* Last cpu to get into this function does the actual work */ + ftrace_modify_all_code(afmcd->command); + wmb(); + atomic_set(&afmcd->done, true); + } else { + /* Other cpus wait for the code modifications to be done */ + rmb(); + while (!atomic_read(&afmcd->done)) + cpu_relax(); + /* Ensure icache is consistent with the code changes */ + __flush_icache_all(); + } + + return 0; +} + +void arch_ftrace_update_code(int command) +{ + struct afmc_data afmcd = { command }; + stop_machine(__arch_ftrace_modify_code, &afmcd, cpu_online_mask); +} + int __init ftrace_dyn_arch_init(void *data) { *(unsigned long *)data = 0; |