diff options
Diffstat (limited to 'arch/csky/kernel/ftrace.c')
-rw-r--r-- | arch/csky/kernel/ftrace.c | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/arch/csky/kernel/ftrace.c b/arch/csky/kernel/ftrace.c new file mode 100644 index 000000000000..274c431f1810 --- /dev/null +++ b/arch/csky/kernel/ftrace.c @@ -0,0 +1,50 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd. + +#include <linux/ftrace.h> +#include <linux/uaccess.h> + +#ifdef CONFIG_FUNCTION_GRAPH_TRACER +void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr, + unsigned long frame_pointer) +{ + unsigned long return_hooker = (unsigned long)&return_to_handler; + unsigned long old; + + if (unlikely(atomic_read(¤t->tracing_graph_pause))) + return; + + old = *parent; + + if (!function_graph_enter(old, self_addr, + *(unsigned long *)frame_pointer, parent)) { + /* + * For csky-gcc function has sub-call: + * subi sp, sp, 8 + * stw r8, (sp, 0) + * mov r8, sp + * st.w r15, (sp, 0x4) + * push r15 + * jl _mcount + * We only need set *parent for resume + * + * For csky-gcc function has no sub-call: + * subi sp, sp, 4 + * stw r8, (sp, 0) + * mov r8, sp + * push r15 + * jl _mcount + * We need set *parent and *(frame_pointer + 4) for resume, + * because lr is resumed twice. + */ + *parent = return_hooker; + frame_pointer += 4; + if (*(unsigned long *)frame_pointer == old) + *(unsigned long *)frame_pointer = return_hooker; + } +} +#endif + +/* _mcount is defined in abi's mcount.S */ +extern void _mcount(void); +EXPORT_SYMBOL(_mcount); |