| Message ID | 20221128101201.4144527-1-guoren@kernel.org (mailing list archive) |
|---|---|
| State | Rejected |
| Headers | show |
| Series | [1/2] riscv: ftrace: Add DYNAMIC_FTRACE_WITH_DIRECT_CALLS support | expand |
| Context | Check | Description |
|---|---|---|
| conchuod/tree_selection | fail | Guessing tree name failed |
Abandoned On Mon, Nov 28, 2022 at 6:12 PM <guoren@kernel.org> wrote: > > From: Song Shuai <suagrfillet@gmail.com> > > This patch adds DYNAMIC_FTRACE_WITH_DIRECT_CALLS support for RISC-V. > > select the DYNAMIC_FTRACE_WITH_DIRECT_CALLS to provide the > register_ftrace_direct[_multi] interfaces allowing users to register > the customed trampoline (direct_caller) as the mcount for one or > more target functions. And modify_ftrace_direct[_multi] are also > provided for modifying direct_caller. > > To make the direct_caller and the other ftrace hooks (eg. function/fgraph > tracer, k[ret]probes) co-exist, a temporary register is nominated to > store the address of direct_caller in ftrace_regs_caller. After the > setting of the address direct_caller by direct_ops->func and the > RESTORE_REGS in ftrace_regs_caller, direct_caller will be jumped to > by the `jr` inst. > > Signed-off-by: Song Shuai <suagrfillet@gmail.com> > Co-developed-by: Guo Ren <guoren@kernel.org> > Signed-off-by: Guo Ren <guoren@kernel.org> > --- > Remove modification of mcount-dyn.S. (Guo Ren) > --- > arch/riscv/Kconfig | 1 + > arch/riscv/include/asm/ftrace.h | 26 ++++++++++++++++++++++++++ > 2 files changed, 27 insertions(+) > > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig > index 1d0e5838b11b..2828537abfcd 100644 > --- a/arch/riscv/Kconfig > +++ b/arch/riscv/Kconfig > @@ -278,6 +278,7 @@ config ARCH_RV64I > select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 > select HAVE_DYNAMIC_FTRACE if !XIP_KERNEL && MMU && $(cc-option,-fpatchable-function-entry=8) > select HAVE_DYNAMIC_FTRACE_WITH_REGS if HAVE_DYNAMIC_FTRACE > + select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS > select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL > select HAVE_FUNCTION_GRAPH_TRACER > select HAVE_FUNCTION_TRACER if !XIP_KERNEL && !PREEMPTION > diff --git a/arch/riscv/include/asm/ftrace.h b/arch/riscv/include/asm/ftrace.h > index 84f856a3286e..d2c159cdfa5c 100644 > --- a/arch/riscv/include/asm/ftrace.h > +++ b/arch/riscv/include/asm/ftrace.h > @@ -114,6 +114,32 @@ struct ftrace_regs; > void ftrace_graph_func(unsigned long ip, unsigned long parent_ip, > struct ftrace_ops *op, struct ftrace_regs *fregs); > #define ftrace_graph_func ftrace_graph_func > + > +static inline void arch_ftrace_set_direct_caller(struct pt_regs *regs, unsigned long addr) > +{ > + /* > + * Backup origin detour target (t0) in t1, and set t0 with addr. > + * > + * Here is the sample code for riscv direct_caller: > + * > + * addi sp,sp,-16 > + * move t0,t1 > + * ^^^^^^^^^^ > + * sd t0,0(sp) > + * sd ra,8(sp) > + * call my_direct_func1 > + * ld t0,0(sp) > + * ld ra,8(sp) > + * addi sp,sp,16 > + * jr t0 > + * > + * (Set t0 with t1 for continuous detour, because t1 contains origin detour > + * target) > + */ > + regs->t1 = regs->t0; > + regs->t0 = addr; > +} > + > #endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */ > > #endif /* __ASSEMBLY__ */ > -- > 2.36.1 >
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index 1d0e5838b11b..2828537abfcd 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -278,6 +278,7 @@ config ARCH_RV64I select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 select HAVE_DYNAMIC_FTRACE if !XIP_KERNEL && MMU && $(cc-option,-fpatchable-function-entry=8) select HAVE_DYNAMIC_FTRACE_WITH_REGS if HAVE_DYNAMIC_FTRACE + select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL select HAVE_FUNCTION_GRAPH_TRACER select HAVE_FUNCTION_TRACER if !XIP_KERNEL && !PREEMPTION diff --git a/arch/riscv/include/asm/ftrace.h b/arch/riscv/include/asm/ftrace.h index 84f856a3286e..d2c159cdfa5c 100644 --- a/arch/riscv/include/asm/ftrace.h +++ b/arch/riscv/include/asm/ftrace.h @@ -114,6 +114,32 @@ struct ftrace_regs; void ftrace_graph_func(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *op, struct ftrace_regs *fregs); #define ftrace_graph_func ftrace_graph_func + +static inline void arch_ftrace_set_direct_caller(struct pt_regs *regs, unsigned long addr) +{ + /* + * Backup origin detour target (t0) in t1, and set t0 with addr. + * + * Here is the sample code for riscv direct_caller: + * + * addi sp,sp,-16 + * move t0,t1 + * ^^^^^^^^^^ + * sd t0,0(sp) + * sd ra,8(sp) + * call my_direct_func1 + * ld t0,0(sp) + * ld ra,8(sp) + * addi sp,sp,16 + * jr t0 + * + * (Set t0 with t1 for continuous detour, because t1 contains origin detour + * target) + */ + regs->t1 = regs->t0; + regs->t0 = addr; +} + #endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */ #endif /* __ASSEMBLY__ */