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author | Alan Kao <alankao@andestech.com> | 2018-02-13 13:13:17 +0800 |
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committer | Palmer Dabbelt <palmer@sifive.com> | 2018-04-02 19:59:12 -0700 |
commit | c15ac4fd60d5ffdb151bb2c7805f377fd7f90363 (patch) | |
tree | 758628a4b5779f5af742da0b1781e8a467736827 /arch/riscv/include/asm | |
parent | a1d2a6b4cee858a2f27eebce731fbf1dfd72cb4e (diff) | |
download | linux-stable-c15ac4fd60d5ffdb151bb2c7805f377fd7f90363.tar.gz linux-stable-c15ac4fd60d5ffdb151bb2c7805f377fd7f90363.tar.bz2 linux-stable-c15ac4fd60d5ffdb151bb2c7805f377fd7f90363.zip |
riscv/ftrace: Add dynamic function tracer support
We now have dynamic ftrace with the following added items:
* ftrace_make_call, ftrace_make_nop (in kernel/ftrace.c)
The two functions turn each recorded call site of filtered functions
into a call to ftrace_caller or nops
* ftracce_update_ftrace_func (in kernel/ftrace.c)
turns the nops at ftrace_call into a call to a generic entry for
function tracers.
* ftrace_caller (in kernel/mcount-dyn.S)
The entry where each _mcount call sites calls to once they are
filtered to be traced.
Also, this patch fixes the semantic problems in mcount.S, which will be
treated as only a reference implementation once we have the dynamic
ftrace.
Cc: Greentime Hu <greentime@andestech.com>
Signed-off-by: Alan Kao <alankao@andestech.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
Diffstat (limited to 'arch/riscv/include/asm')
-rw-r--r-- | arch/riscv/include/asm/ftrace.h | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/arch/riscv/include/asm/ftrace.h b/arch/riscv/include/asm/ftrace.h index 66d4175eb13e..078743aacfd3 100644 --- a/arch/riscv/include/asm/ftrace.h +++ b/arch/riscv/include/asm/ftrace.h @@ -8,3 +8,57 @@ #if defined(CONFIG_FUNCTION_GRAPH_TRACER) && defined(CONFIG_FRAME_POINTER) #define HAVE_FUNCTION_GRAPH_FP_TEST #endif + +#ifndef __ASSEMBLY__ +void _mcount(void); +static inline unsigned long ftrace_call_adjust(unsigned long addr) +{ + return addr; +} + +struct dyn_arch_ftrace { +}; +#endif + +#ifdef CONFIG_DYNAMIC_FTRACE +/* + * A general call in RISC-V is a pair of insts: + * 1) auipc: setting high-20 pc-related bits to ra register + * 2) jalr: setting low-12 offset to ra, jump to ra, and set ra to + * return address (original pc + 4) + * + * Dynamic ftrace generates probes to call sites, so we must deal with + * both auipc and jalr at the same time. + */ + +#define MCOUNT_ADDR ((unsigned long)_mcount) +#define JALR_SIGN_MASK (0x00000800) +#define JALR_OFFSET_MASK (0x00000fff) +#define AUIPC_OFFSET_MASK (0xfffff000) +#define AUIPC_PAD (0x00001000) +#define JALR_SHIFT 20 +#define JALR_BASIC (0x000080e7) +#define AUIPC_BASIC (0x00000097) +#define NOP4 (0x00000013) + +#define make_call(caller, callee, call) \ +do { \ + call[0] = to_auipc_insn((unsigned int)((unsigned long)callee - \ + (unsigned long)caller)); \ + call[1] = to_jalr_insn((unsigned int)((unsigned long)callee - \ + (unsigned long)caller)); \ +} while (0) + +#define to_jalr_insn(offset) \ + (((offset & JALR_OFFSET_MASK) << JALR_SHIFT) | JALR_BASIC) + +#define to_auipc_insn(offset) \ + ((offset & JALR_SIGN_MASK) ? \ + (((offset & AUIPC_OFFSET_MASK) + AUIPC_PAD) | AUIPC_BASIC) : \ + ((offset & AUIPC_OFFSET_MASK) | AUIPC_BASIC)) + +/* + * Let auipc+jalr be the basic *mcount unit*, so we make it 8 bytes here. + */ +#define MCOUNT_INSN_SIZE 8 +#endif |