296 lines
7.4 KiB
C
Executable file
296 lines
7.4 KiB
C
Executable file
// SPDX-License-Identifier: GPL-2.0
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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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#ifndef CONFIG_DYNAMIC_FTRACE
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extern void (*ftrace_trace_function)(unsigned long, unsigned long,
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struct ftrace_ops*, struct pt_regs*);
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extern int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace);
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extern void ftrace_graph_caller(void);
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noinline void __naked ftrace_stub(unsigned long ip, unsigned long parent_ip,
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struct ftrace_ops *op, struct pt_regs *regs)
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{
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__asm__ (""); /* avoid to optimize as pure function */
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}
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noinline void _mcount(unsigned long parent_ip)
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{
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/* save all state by the compiler prologue */
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unsigned long ip = (unsigned long)__builtin_return_address(0);
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if (ftrace_trace_function != ftrace_stub)
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ftrace_trace_function(ip - MCOUNT_INSN_SIZE, parent_ip,
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NULL, NULL);
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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if (ftrace_graph_return != (trace_func_graph_ret_t)ftrace_stub
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|| ftrace_graph_entry != ftrace_graph_entry_stub)
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ftrace_graph_caller();
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#endif
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/* restore all state by the compiler epilogue */
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}
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EXPORT_SYMBOL(_mcount);
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#else /* CONFIG_DYNAMIC_FTRACE */
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noinline void __naked ftrace_stub(unsigned long ip, unsigned long parent_ip,
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struct ftrace_ops *op, struct pt_regs *regs)
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{
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__asm__ (""); /* avoid to optimize as pure function */
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}
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noinline void __naked _mcount(unsigned long parent_ip)
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{
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__asm__ (""); /* avoid to optimize as pure function */
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}
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EXPORT_SYMBOL(_mcount);
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#define XSTR(s) STR(s)
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#define STR(s) #s
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void _ftrace_caller(unsigned long parent_ip)
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{
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/* save all state needed by the compiler prologue */
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/*
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* prepare arguments for real tracing function
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* first arg : __builtin_return_address(0) - MCOUNT_INSN_SIZE
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* second arg : parent_ip
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*/
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__asm__ __volatile__ (
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"move $r1, %0 \n\t"
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"addi $r0, %1, #-" XSTR(MCOUNT_INSN_SIZE) "\n\t"
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:
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: "r" (parent_ip), "r" (__builtin_return_address(0)));
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/* a placeholder for the call to a real tracing function */
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__asm__ __volatile__ (
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"ftrace_call: \n\t"
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"nop \n\t"
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"nop \n\t"
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"nop \n\t");
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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/* a placeholder for the call to ftrace_graph_caller */
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__asm__ __volatile__ (
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"ftrace_graph_call: \n\t"
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"nop \n\t"
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"nop \n\t"
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"nop \n\t");
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#endif
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/* restore all state needed by the compiler epilogue */
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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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int ftrace_arch_code_modify_prepare(void)
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{
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set_all_modules_text_rw();
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return 0;
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}
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int ftrace_arch_code_modify_post_process(void)
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{
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set_all_modules_text_ro();
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return 0;
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}
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static unsigned long gen_sethi_insn(unsigned long addr)
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{
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unsigned long opcode = 0x46000000;
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unsigned long imm = addr >> 12;
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unsigned long rt_num = 0xf << 20;
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return ENDIAN_CONVERT(opcode | rt_num | imm);
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}
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static unsigned long gen_ori_insn(unsigned long addr)
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{
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unsigned long opcode = 0x58000000;
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unsigned long imm = addr & 0x0000fff;
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unsigned long rt_num = 0xf << 20;
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unsigned long ra_num = 0xf << 15;
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return ENDIAN_CONVERT(opcode | rt_num | ra_num | imm);
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}
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static unsigned long gen_jral_insn(unsigned long addr)
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{
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unsigned long opcode = 0x4a000001;
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unsigned long rt_num = 0x1e << 20;
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unsigned long rb_num = 0xf << 10;
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return ENDIAN_CONVERT(opcode | rt_num | rb_num);
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}
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static void ftrace_gen_call_insn(unsigned long *call_insns,
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unsigned long addr)
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{
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call_insns[0] = gen_sethi_insn(addr); /* sethi $r15, imm20u */
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call_insns[1] = gen_ori_insn(addr); /* ori $r15, $r15, imm15u */
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call_insns[2] = gen_jral_insn(addr); /* jral $lp, $r15 */
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}
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static int __ftrace_modify_code(unsigned long pc, unsigned long *old_insn,
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unsigned long *new_insn, bool validate)
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{
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unsigned long orig_insn[3];
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if (validate) {
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if (probe_kernel_read(orig_insn, (void *)pc, MCOUNT_INSN_SIZE))
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return -EFAULT;
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if (memcmp(orig_insn, old_insn, MCOUNT_INSN_SIZE))
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return -EINVAL;
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}
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if (probe_kernel_write((void *)pc, new_insn, MCOUNT_INSN_SIZE))
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return -EPERM;
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return 0;
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}
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static int ftrace_modify_code(unsigned long pc, unsigned long *old_insn,
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unsigned long *new_insn, bool validate)
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{
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int ret;
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ret = __ftrace_modify_code(pc, old_insn, new_insn, validate);
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if (ret)
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return ret;
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flush_icache_range(pc, pc + MCOUNT_INSN_SIZE);
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return ret;
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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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unsigned long pc = (unsigned long)&ftrace_call;
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unsigned long old_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};
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unsigned long new_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};
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if (func != ftrace_stub)
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ftrace_gen_call_insn(new_insn, (unsigned long)func);
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return ftrace_modify_code(pc, old_insn, new_insn, false);
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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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unsigned long pc = rec->ip;
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unsigned long nop_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};
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unsigned long call_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};
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ftrace_gen_call_insn(call_insn, addr);
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return ftrace_modify_code(pc, nop_insn, call_insn, true);
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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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unsigned long pc = rec->ip;
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unsigned long nop_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};
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unsigned long call_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};
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ftrace_gen_call_insn(call_insn, addr);
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return ftrace_modify_code(pc, call_insn, nop_insn, true);
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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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unsigned long frame_pointer)
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{
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unsigned long return_hooker = (unsigned long)&return_to_handler;
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unsigned long old;
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if (unlikely(atomic_read(¤t->tracing_graph_pause)))
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return;
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old = *parent;
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if (!function_graph_enter(old, self_addr, frame_pointer, NULL))
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*parent = return_hooker;
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}
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noinline void ftrace_graph_caller(void)
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{
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unsigned long *parent_ip =
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(unsigned long *)(__builtin_frame_address(2) - 4);
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unsigned long selfpc =
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(unsigned long)(__builtin_return_address(1) - MCOUNT_INSN_SIZE);
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unsigned long frame_pointer =
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(unsigned long)__builtin_frame_address(3);
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prepare_ftrace_return(parent_ip, selfpc, frame_pointer);
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}
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extern unsigned long ftrace_return_to_handler(unsigned long frame_pointer);
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void __naked return_to_handler(void)
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{
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__asm__ __volatile__ (
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/* save state needed by the ABI */
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"smw.adm $r0,[$sp],$r1,#0x0 \n\t"
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/* get original return address */
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"move $r0, $fp \n\t"
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"bal ftrace_return_to_handler\n\t"
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"move $lp, $r0 \n\t"
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/* restore state nedded by the ABI */
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"lmw.bim $r0,[$sp],$r1,#0x0 \n\t");
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}
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#ifdef CONFIG_DYNAMIC_FTRACE
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extern unsigned long ftrace_graph_call;
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static int ftrace_modify_graph_caller(bool enable)
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{
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unsigned long pc = (unsigned long)&ftrace_graph_call;
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unsigned long nop_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};
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unsigned long call_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};
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ftrace_gen_call_insn(call_insn, (unsigned long)ftrace_graph_caller);
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if (enable)
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return ftrace_modify_code(pc, nop_insn, call_insn, true);
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else
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return ftrace_modify_code(pc, call_insn, nop_insn, true);
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}
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int ftrace_enable_ftrace_graph_caller(void)
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{
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return ftrace_modify_graph_caller(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_graph_caller(false);
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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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#ifdef CONFIG_TRACE_IRQFLAGS
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noinline void __trace_hardirqs_off(void)
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{
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trace_hardirqs_off();
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}
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noinline void __trace_hardirqs_on(void)
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{
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trace_hardirqs_on();
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}
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#endif /* CONFIG_TRACE_IRQFLAGS */
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