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 <ren_guo@c-sky.com>hifive-unleashed-5.2
Guo Ren
parent
3dfc242f11
commit
28bb030f93
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@ -29,13 +29,14 @@ config CSKY
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select GENERIC_SCHED_CLOCK
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select GENERIC_SMP_IDLE_THREAD
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select HAVE_ARCH_TRACEHOOK
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select HAVE_DYNAMIC_FTRACE
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select HAVE_FUNCTION_TRACER
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select HAVE_FUNCTION_GRAPH_TRACER
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select HAVE_FTRACE_MCOUNT_RECORD
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select HAVE_KERNEL_GZIP
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select HAVE_KERNEL_LZO
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select HAVE_KERNEL_LZMA
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select HAVE_PERF_EVENTS
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select HAVE_C_RECORDMCOUNT
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select HAVE_DMA_API_DEBUG
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select HAVE_DMA_CONTIGUOUS
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select MAY_HAVE_SPARSE_IRQ
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@ -61,10 +61,17 @@
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addi sp, 16
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.endm
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.macro nop32_stub
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nop32
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nop32
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nop32
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.endm
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ENTRY(ftrace_stub)
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jmp lr
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END(ftrace_stub)
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#ifndef CONFIG_DYNAMIC_FTRACE
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ENTRY(_mcount)
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mcount_enter
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@ -76,7 +83,7 @@ ENTRY(_mcount)
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bf skip_ftrace
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mov a0, lr
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subi a0, MCOUNT_INSN_SIZE
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subi a0, 4
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ldw a1, (sp, 24)
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jsr r26
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@ -101,13 +108,41 @@ skip_ftrace:
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mcount_exit
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#endif
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END(_mcount)
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#else /* CONFIG_DYNAMIC_FTRACE */
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ENTRY(_mcount)
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mov t1, lr
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ldw lr, (sp, 0)
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addi sp, 4
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jmp t1
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ENDPROC(_mcount)
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ENTRY(ftrace_caller)
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mcount_enter
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ldw a0, (sp, 16)
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subi a0, 4
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ldw a1, (sp, 24)
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nop
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GLOBAL(ftrace_call)
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nop32_stub
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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nop
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GLOBAL(ftrace_graph_call)
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nop32_stub
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#endif
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mcount_exit
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ENDPROC(ftrace_caller)
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#endif /* CONFIG_DYNAMIC_FTRACE */
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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ENTRY(ftrace_graph_caller)
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mov a0, sp
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addi a0, 24
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ldw a1, (sp, 16)
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subi a1, MCOUNT_INSN_SIZE
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subi a1, 4
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mov a2, r8
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lrw r26, prepare_ftrace_return
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jsr r26
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@ -4,10 +4,26 @@
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#ifndef __ASM_CSKY_FTRACE_H
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#define __ASM_CSKY_FTRACE_H
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#define MCOUNT_INSN_SIZE 4
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#define MCOUNT_INSN_SIZE 14
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#define HAVE_FUNCTION_GRAPH_FP_TEST
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#define HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
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#define MCOUNT_ADDR ((unsigned long)_mcount)
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#ifndef __ASSEMBLY__
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extern void _mcount(unsigned long);
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extern void ftrace_graph_call(void);
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static inline unsigned long ftrace_call_adjust(unsigned long addr)
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{
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return addr;
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}
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struct dyn_arch_ftrace {
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};
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#endif /* !__ASSEMBLY__ */
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#endif /* __ASM_CSKY_FTRACE_H */
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@ -3,6 +3,137 @@
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#include <linux/ftrace.h>
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#include <linux/uaccess.h>
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#include <asm/cacheflush.h>
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#ifdef CONFIG_DYNAMIC_FTRACE
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#define NOP 0x4000
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#define NOP32_HI 0xc400
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#define NOP32_LO 0x4820
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#define PUSH_LR 0x14d0
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#define MOVIH_LINK 0xea3a
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#define ORI_LINK 0xef5a
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#define JSR_LINK 0xe8fa
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#define BSR_LINK 0xe000
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/*
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* Gcc-csky with -pg will insert stub in function prologue:
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* push lr
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* jbsr _mcount
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* nop32
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* nop32
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*
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* If the (callee - current_pc) is less then 64MB, we'll use bsr:
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* push lr
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* bsr _mcount
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* nop32
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* nop32
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* else we'll use (movih + ori + jsr):
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* push lr
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* movih r26, ...
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* ori r26, ...
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* jsr r26
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*
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* (r26 is our reserved link-reg)
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*
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*/
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static inline void make_jbsr(unsigned long callee, unsigned long pc,
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uint16_t *call, bool nolr)
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{
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long offset;
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call[0] = nolr ? NOP : PUSH_LR;
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offset = (long) callee - (long) pc;
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if (unlikely(offset < -67108864 || offset > 67108864)) {
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call[1] = MOVIH_LINK;
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call[2] = callee >> 16;
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call[3] = ORI_LINK;
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call[4] = callee & 0xffff;
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call[5] = JSR_LINK;
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call[6] = 0;
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} else {
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offset = offset >> 1;
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call[1] = BSR_LINK |
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((uint16_t)((unsigned long) offset >> 16) & 0x3ff);
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call[2] = (uint16_t)((unsigned long) offset & 0xffff);
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call[3] = call[5] = NOP32_HI;
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call[4] = call[6] = NOP32_LO;
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}
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}
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static uint16_t nops[7] = {NOP, NOP32_HI, NOP32_LO, NOP32_HI, NOP32_LO,
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NOP32_HI, NOP32_LO};
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static int ftrace_check_current_nop(unsigned long hook)
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{
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uint16_t olds[7];
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unsigned long hook_pos = hook - 2;
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if (probe_kernel_read((void *)olds, (void *)hook_pos, sizeof(nops)))
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return -EFAULT;
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if (memcmp((void *)nops, (void *)olds, sizeof(nops))) {
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pr_err("%p: nop but get (%04x %04x %04x %04x %04x %04x %04x)\n",
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(void *)hook_pos,
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olds[0], olds[1], olds[2], olds[3], olds[4], olds[5],
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olds[6]);
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return -EINVAL;
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}
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return 0;
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}
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static int ftrace_modify_code(unsigned long hook, unsigned long target,
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bool enable, bool nolr)
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{
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uint16_t call[7];
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unsigned long hook_pos = hook - 2;
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int ret = 0;
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make_jbsr(target, hook, call, nolr);
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ret = probe_kernel_write((void *)hook_pos, enable ? call : nops,
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sizeof(nops));
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if (ret)
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return -EPERM;
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flush_icache_range(hook_pos, hook_pos + MCOUNT_INSN_SIZE);
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return 0;
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}
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int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
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{
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int ret = ftrace_check_current_nop(rec->ip);
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if (ret)
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return ret;
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return ftrace_modify_code(rec->ip, addr, true, false);
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}
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int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec,
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unsigned long addr)
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{
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return ftrace_modify_code(rec->ip, addr, false, false);
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}
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int ftrace_update_ftrace_func(ftrace_func_t func)
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{
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int ret = ftrace_modify_code((unsigned long)&ftrace_call,
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(unsigned long)func, true, true);
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return ret;
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}
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int __init ftrace_dyn_arch_init(void)
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{
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return 0;
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}
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#endif /* CONFIG_DYNAMIC_FTRACE */
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
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@ -43,8 +174,21 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
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*(unsigned long *)frame_pointer = return_hooker;
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}
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}
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#endif
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#ifdef CONFIG_DYNAMIC_FTRACE
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int ftrace_enable_ftrace_graph_caller(void)
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{
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return ftrace_modify_code((unsigned long)&ftrace_graph_call,
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(unsigned long)&ftrace_graph_caller, true, true);
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}
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int ftrace_disable_ftrace_graph_caller(void)
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{
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return ftrace_modify_code((unsigned long)&ftrace_graph_call,
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(unsigned long)&ftrace_graph_caller, false, true);
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}
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#endif /* CONFIG_DYNAMIC_FTRACE */
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#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
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/* _mcount is defined in abi's mcount.S */
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extern void _mcount(void);
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EXPORT_SYMBOL(_mcount);
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@ -397,6 +397,9 @@ if ($arch eq "x86_64") {
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} elsif ($arch eq "nds32") {
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$mcount_regex = "^\\s*([0-9a-fA-F]+):\\s*R_NDS32_HI20_RELA\\s+_mcount\$";
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$alignment = 2;
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} elsif ($arch eq "csky") {
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$mcount_regex = "^\\s*([0-9a-fA-F]+):\\s*R_CKCORE_PCREL_JSR_IMM26BY2\\s+_mcount\$";
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$alignment = 2;
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} else {
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die "Arch $arch is not supported with CONFIG_FTRACE_MCOUNT_RECORD";
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}
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