From 28bb030f93334495ddc64ade0bff18721bf7023d Mon Sep 17 00:00:00 2001 From: Guo Ren Date: Fri, 1 Mar 2019 08:50:36 +0800 Subject: [PATCH] csky/ftrace: Add dynamic function tracer (include graph tracer) Support dynamic ftrace including dynamic graph tracer. Gcc-csky with -pg will produce call site in every function prologue and we can use these call site to hook trace function. gcc with -pg origin call site: push lr jbsr _mcount nop32 nop32 If the (callee - caller)'s offset is in range of bsr instruction, we'll modify code with: push lr bsr _mcount nop32 nop32 Else if the (callee - caller)'s offset is out of bsr instrunction, we'll modify code with: push lr movih r26, ... ori r26, ... jsr r26 (r26 is reserved for jsr link reg in csky abiv2 spec.) Signed-off-by: Guo Ren --- arch/csky/Kconfig | 3 +- arch/csky/abiv2/mcount.S | 39 ++++++++- arch/csky/include/asm/ftrace.h | 18 +++- arch/csky/kernel/ftrace.c | 148 ++++++++++++++++++++++++++++++++- scripts/recordmcount.pl | 3 + 5 files changed, 205 insertions(+), 6 deletions(-) diff --git a/arch/csky/Kconfig b/arch/csky/Kconfig index 725a115759c9..60ebaa325584 100644 --- a/arch/csky/Kconfig +++ b/arch/csky/Kconfig @@ -29,13 +29,14 @@ config CSKY select GENERIC_SCHED_CLOCK select GENERIC_SMP_IDLE_THREAD select HAVE_ARCH_TRACEHOOK + select HAVE_DYNAMIC_FTRACE select HAVE_FUNCTION_TRACER select HAVE_FUNCTION_GRAPH_TRACER + select HAVE_FTRACE_MCOUNT_RECORD select HAVE_KERNEL_GZIP select HAVE_KERNEL_LZO select HAVE_KERNEL_LZMA select HAVE_PERF_EVENTS - select HAVE_C_RECORDMCOUNT select HAVE_DMA_API_DEBUG select HAVE_DMA_CONTIGUOUS select MAY_HAVE_SPARSE_IRQ diff --git a/arch/csky/abiv2/mcount.S b/arch/csky/abiv2/mcount.S index c633379956f5..326402e65f9e 100644 --- a/arch/csky/abiv2/mcount.S +++ b/arch/csky/abiv2/mcount.S @@ -61,10 +61,17 @@ addi sp, 16 .endm +.macro nop32_stub + nop32 + nop32 + nop32 +.endm + ENTRY(ftrace_stub) jmp lr END(ftrace_stub) +#ifndef CONFIG_DYNAMIC_FTRACE ENTRY(_mcount) mcount_enter @@ -76,7 +83,7 @@ ENTRY(_mcount) bf skip_ftrace mov a0, lr - subi a0, MCOUNT_INSN_SIZE + subi a0, 4 ldw a1, (sp, 24) jsr r26 @@ -101,13 +108,41 @@ skip_ftrace: mcount_exit #endif END(_mcount) +#else /* CONFIG_DYNAMIC_FTRACE */ +ENTRY(_mcount) + mov t1, lr + ldw lr, (sp, 0) + addi sp, 4 + jmp t1 +ENDPROC(_mcount) + +ENTRY(ftrace_caller) + mcount_enter + + ldw a0, (sp, 16) + subi a0, 4 + ldw a1, (sp, 24) + + nop +GLOBAL(ftrace_call) + nop32_stub + +#ifdef CONFIG_FUNCTION_GRAPH_TRACER + nop +GLOBAL(ftrace_graph_call) + nop32_stub +#endif + + mcount_exit +ENDPROC(ftrace_caller) +#endif /* CONFIG_DYNAMIC_FTRACE */ #ifdef CONFIG_FUNCTION_GRAPH_TRACER ENTRY(ftrace_graph_caller) mov a0, sp addi a0, 24 ldw a1, (sp, 16) - subi a1, MCOUNT_INSN_SIZE + subi a1, 4 mov a2, r8 lrw r26, prepare_ftrace_return jsr r26 diff --git a/arch/csky/include/asm/ftrace.h b/arch/csky/include/asm/ftrace.h index 7547c45312a8..ba35d93ecda2 100644 --- a/arch/csky/include/asm/ftrace.h +++ b/arch/csky/include/asm/ftrace.h @@ -4,10 +4,26 @@ #ifndef __ASM_CSKY_FTRACE_H #define __ASM_CSKY_FTRACE_H -#define MCOUNT_INSN_SIZE 4 +#define MCOUNT_INSN_SIZE 14 #define HAVE_FUNCTION_GRAPH_FP_TEST #define HAVE_FUNCTION_GRAPH_RET_ADDR_PTR +#define MCOUNT_ADDR ((unsigned long)_mcount) + +#ifndef __ASSEMBLY__ + +extern void _mcount(unsigned long); + +extern void ftrace_graph_call(void); + +static inline unsigned long ftrace_call_adjust(unsigned long addr) +{ + return addr; +} + +struct dyn_arch_ftrace { +}; +#endif /* !__ASSEMBLY__ */ #endif /* __ASM_CSKY_FTRACE_H */ diff --git a/arch/csky/kernel/ftrace.c b/arch/csky/kernel/ftrace.c index 274c431f1810..44f4880179b7 100644 --- a/arch/csky/kernel/ftrace.c +++ b/arch/csky/kernel/ftrace.c @@ -3,6 +3,137 @@ #include #include +#include + +#ifdef CONFIG_DYNAMIC_FTRACE + +#define NOP 0x4000 +#define NOP32_HI 0xc400 +#define NOP32_LO 0x4820 +#define PUSH_LR 0x14d0 +#define MOVIH_LINK 0xea3a +#define ORI_LINK 0xef5a +#define JSR_LINK 0xe8fa +#define BSR_LINK 0xe000 + +/* + * Gcc-csky with -pg will insert stub in function prologue: + * push lr + * jbsr _mcount + * nop32 + * nop32 + * + * If the (callee - current_pc) is less then 64MB, we'll use bsr: + * push lr + * bsr _mcount + * nop32 + * nop32 + * else we'll use (movih + ori + jsr): + * push lr + * movih r26, ... + * ori r26, ... + * jsr r26 + * + * (r26 is our reserved link-reg) + * + */ +static inline void make_jbsr(unsigned long callee, unsigned long pc, + uint16_t *call, bool nolr) +{ + long offset; + + call[0] = nolr ? NOP : PUSH_LR; + + offset = (long) callee - (long) pc; + + if (unlikely(offset < -67108864 || offset > 67108864)) { + call[1] = MOVIH_LINK; + call[2] = callee >> 16; + call[3] = ORI_LINK; + call[4] = callee & 0xffff; + call[5] = JSR_LINK; + call[6] = 0; + } else { + offset = offset >> 1; + + call[1] = BSR_LINK | + ((uint16_t)((unsigned long) offset >> 16) & 0x3ff); + call[2] = (uint16_t)((unsigned long) offset & 0xffff); + call[3] = call[5] = NOP32_HI; + call[4] = call[6] = NOP32_LO; + } +} + +static uint16_t nops[7] = {NOP, NOP32_HI, NOP32_LO, NOP32_HI, NOP32_LO, + NOP32_HI, NOP32_LO}; +static int ftrace_check_current_nop(unsigned long hook) +{ + uint16_t olds[7]; + unsigned long hook_pos = hook - 2; + + if (probe_kernel_read((void *)olds, (void *)hook_pos, sizeof(nops))) + return -EFAULT; + + if (memcmp((void *)nops, (void *)olds, sizeof(nops))) { + pr_err("%p: nop but get (%04x %04x %04x %04x %04x %04x %04x)\n", + (void *)hook_pos, + olds[0], olds[1], olds[2], olds[3], olds[4], olds[5], + olds[6]); + + return -EINVAL; + } + + return 0; +} + +static int ftrace_modify_code(unsigned long hook, unsigned long target, + bool enable, bool nolr) +{ + uint16_t call[7]; + + unsigned long hook_pos = hook - 2; + int ret = 0; + + make_jbsr(target, hook, call, nolr); + + ret = probe_kernel_write((void *)hook_pos, enable ? call : nops, + sizeof(nops)); + if (ret) + return -EPERM; + + flush_icache_range(hook_pos, hook_pos + MCOUNT_INSN_SIZE); + + return 0; +} + +int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) +{ + int ret = ftrace_check_current_nop(rec->ip); + + if (ret) + return ret; + + return ftrace_modify_code(rec->ip, addr, true, false); +} + +int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, + unsigned long addr) +{ + return ftrace_modify_code(rec->ip, addr, false, false); +} + +int ftrace_update_ftrace_func(ftrace_func_t func) +{ + int ret = ftrace_modify_code((unsigned long)&ftrace_call, + (unsigned long)func, true, true); + return ret; +} + +int __init ftrace_dyn_arch_init(void) +{ + return 0; +} +#endif /* CONFIG_DYNAMIC_FTRACE */ #ifdef CONFIG_FUNCTION_GRAPH_TRACER void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr, @@ -43,8 +174,21 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr, *(unsigned long *)frame_pointer = return_hooker; } } -#endif + +#ifdef CONFIG_DYNAMIC_FTRACE +int ftrace_enable_ftrace_graph_caller(void) +{ + return ftrace_modify_code((unsigned long)&ftrace_graph_call, + (unsigned long)&ftrace_graph_caller, true, true); +} + +int ftrace_disable_ftrace_graph_caller(void) +{ + return ftrace_modify_code((unsigned long)&ftrace_graph_call, + (unsigned long)&ftrace_graph_caller, false, true); +} +#endif /* CONFIG_DYNAMIC_FTRACE */ +#endif /* CONFIG_FUNCTION_GRAPH_TRACER */ /* _mcount is defined in abi's mcount.S */ -extern void _mcount(void); EXPORT_SYMBOL(_mcount); diff --git a/scripts/recordmcount.pl b/scripts/recordmcount.pl index 68841d01162c..f71666899245 100755 --- a/scripts/recordmcount.pl +++ b/scripts/recordmcount.pl @@ -397,6 +397,9 @@ if ($arch eq "x86_64") { } elsif ($arch eq "nds32") { $mcount_regex = "^\\s*([0-9a-fA-F]+):\\s*R_NDS32_HI20_RELA\\s+_mcount\$"; $alignment = 2; +} elsif ($arch eq "csky") { + $mcount_regex = "^\\s*([0-9a-fA-F]+):\\s*R_CKCORE_PCREL_JSR_IMM26BY2\\s+_mcount\$"; + $alignment = 2; } else { die "Arch $arch is not supported with CONFIG_FTRACE_MCOUNT_RECORD"; }