diff options
Diffstat (limited to 'arch/x86/kernel/ftrace.c')
| -rw-r--r-- | arch/x86/kernel/ftrace.c | 28 |
1 files changed, 20 insertions, 8 deletions
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c index cbd73eb42170..0651e974dcb3 100644 --- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -24,17 +24,11 @@ #include <trace/syscall.h> -#include <asm/cacheflush.h> +#include <asm/set_memory.h> #include <asm/kprobes.h> #include <asm/ftrace.h> #include <asm/nops.h> -#if defined(CONFIG_FUNCTION_GRAPH_TRACER) && \ - !defined(CC_USING_FENTRY) && \ - !defined(CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE) -# error The following combination is not supported: ((compiler missing -mfentry) || (CONFIG_X86_32 and !CONFIG_DYNAMIC_FTRACE)) && CONFIG_FUNCTION_GRAPH_TRACER && CONFIG_CC_OPTIMIZE_FOR_SIZE -#endif - #ifdef CONFIG_DYNAMIC_FTRACE int ftrace_arch_code_modify_prepare(void) @@ -539,7 +533,13 @@ static void do_sync_core(void *data) static void run_sync(void) { - int enable_irqs = irqs_disabled(); + int enable_irqs; + + /* No need to sync if there's only one CPU */ + if (num_online_cpus() == 1) + return; + + enable_irqs = irqs_disabled(); /* We may be called with interrupts disabled (on bootup). */ if (enable_irqs) @@ -989,6 +989,18 @@ void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent, unsigned long return_hooker = (unsigned long) &return_to_handler; + /* + * When resuming from suspend-to-ram, this function can be indirectly + * called from early CPU startup code while the CPU is in real mode, + * which would fail miserably. Make sure the stack pointer is a + * virtual address. + * + * This check isn't as accurate as virt_addr_valid(), but it should be + * good enough for this purpose, and it's fast. + */ + if (unlikely((long)__builtin_frame_address(0) >= 0)) + return; + if (unlikely(ftrace_graph_is_dead())) return; |