diff options
| author | Abel Vesa <abelvesa@linux.com> | 2017-05-26 21:49:47 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@armlinux.org.uk> | 2017-06-18 22:25:16 +0100 |
| commit | 620176f335017fbfcbc79d26a8c9beb6e64f4868 (patch) | |
| tree | e5865d1ab6cfe66b5009ce118c08d4b9cc49a711 /arch/arm/kernel/ftrace.c | |
| parent | 1515b186c2359996b50241c1c6f79ff933d5112a (diff) | |
ARM: 8678/1: ftrace: Adds support for CONFIG_DYNAMIC_FTRACE_WITH_REGS
The DYNAMIC_FTRACE_WITH_REGS configuration makes it possible for a
ftrace operation to specify if registers need to saved/restored by
the ftrace handler. This is needed by kgraft and possibly other
ftrace-based tools, and the ARM architecture is currently lacking
this feature. It would also be the first step to support the
"Kprobes-on-ftrace" optimization on ARM.
This patch introduces a new ftrace handler that stores the registers
on the stack before calling the next stage. The registers are restored
from the stack before going back to the instrumented function.
A side-effect of this patch is to activate the support for
ftrace_modify_call() as it defines ARCH_SUPPORTS_FTRACE_OPS for the
ARM architecture.
Signed-off-by: Abel Vesa <abelvesa@linux.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Diffstat (limited to 'arch/arm/kernel/ftrace.c')
| -rw-r--r-- | arch/arm/kernel/ftrace.c | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/arch/arm/kernel/ftrace.c b/arch/arm/kernel/ftrace.c index 833c991075a1..5617932a83df 100644 --- a/arch/arm/kernel/ftrace.c +++ b/arch/arm/kernel/ftrace.c @@ -141,6 +141,15 @@ int ftrace_update_ftrace_func(ftrace_func_t func) ret = ftrace_modify_code(pc, 0, new, false); +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS + if (!ret) { + pc = (unsigned long)&ftrace_regs_call; + new = ftrace_call_replace(pc, (unsigned long)func); + + ret = ftrace_modify_code(pc, 0, new, false); + } +#endif + #ifdef CONFIG_OLD_MCOUNT if (!ret) { pc = (unsigned long)&ftrace_call_old; @@ -159,11 +168,29 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) unsigned long ip = rec->ip; old = ftrace_nop_replace(rec); + + new = ftrace_call_replace(ip, adjust_address(rec, addr)); + + return ftrace_modify_code(rec->ip, old, new, true); +} + +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS + +int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, + unsigned long addr) +{ + unsigned long new, old; + unsigned long ip = rec->ip; + + old = ftrace_call_replace(ip, adjust_address(rec, old_addr)); + new = ftrace_call_replace(ip, adjust_address(rec, addr)); return ftrace_modify_code(rec->ip, old, new, true); } +#endif + int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr) { @@ -231,6 +258,8 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr, extern unsigned long ftrace_graph_call; extern unsigned long ftrace_graph_call_old; extern void ftrace_graph_caller_old(void); +extern unsigned long ftrace_graph_regs_call; +extern void ftrace_graph_regs_caller(void); static int __ftrace_modify_caller(unsigned long *callsite, void (*func) (void), bool enable) @@ -253,6 +282,14 @@ static int ftrace_modify_graph_caller(bool enable) ftrace_graph_caller, enable); +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS + if (!ret) + ret = __ftrace_modify_caller(&ftrace_graph_regs_call, + ftrace_graph_regs_caller, + enable); +#endif + + #ifdef CONFIG_OLD_MCOUNT if (!ret) ret = __ftrace_modify_caller(&ftrace_graph_call_old, |