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222 lines
5.8 KiB
222 lines
5.8 KiB
/* |
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* Ftrace support for Microblaze. |
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* |
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* Copyright (C) 2009 Michal Simek <[email protected]> |
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* Copyright (C) 2009 PetaLogix |
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* |
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* Based on MIPS and PowerPC ftrace code |
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* |
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* This file is subject to the terms and conditions of the GNU General Public |
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* License. See the file "COPYING" in the main directory of this archive |
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* for more details. |
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*/ |
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#include <asm/cacheflush.h> |
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#include <linux/ftrace.h> |
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER |
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/* |
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* Hook the return address and push it in the stack of return addrs |
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* in current thread info. |
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*/ |
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void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr) |
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{ |
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unsigned long old; |
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int faulted; |
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unsigned long return_hooker = (unsigned long) |
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&return_to_handler; |
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if (unlikely(ftrace_graph_is_dead())) |
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return; |
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if (unlikely(atomic_read(¤t->tracing_graph_pause))) |
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return; |
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/* |
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* Protect against fault, even if it shouldn't |
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* happen. This tool is too much intrusive to |
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* ignore such a protection. |
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*/ |
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asm volatile(" 1: lwi %0, %2, 0;" \ |
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"2: swi %3, %2, 0;" \ |
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" addik %1, r0, 0;" \ |
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"3:" \ |
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" .section .fixup, \"ax\";" \ |
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"4: brid 3b;" \ |
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" addik %1, r0, 1;" \ |
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" .previous;" \ |
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" .section __ex_table,\"a\";" \ |
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" .word 1b,4b;" \ |
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" .word 2b,4b;" \ |
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" .previous;" \ |
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: "=&r" (old), "=r" (faulted) |
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: "r" (parent), "r" (return_hooker) |
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); |
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flush_dcache_range((u32)parent, (u32)parent + 4); |
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flush_icache_range((u32)parent, (u32)parent + 4); |
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if (unlikely(faulted)) { |
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ftrace_graph_stop(); |
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WARN_ON(1); |
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return; |
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} |
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if (function_graph_enter(old, self_addr, 0, NULL)) |
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*parent = old; |
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} |
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#endif /* CONFIG_FUNCTION_GRAPH_TRACER */ |
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#ifdef CONFIG_DYNAMIC_FTRACE |
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/* save value to addr - it is save to do it in asm */ |
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static int ftrace_modify_code(unsigned long addr, unsigned int value) |
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{ |
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int faulted = 0; |
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__asm__ __volatile__(" 1: swi %2, %1, 0;" \ |
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" addik %0, r0, 0;" \ |
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"2:" \ |
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" .section .fixup, \"ax\";" \ |
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"3: brid 2b;" \ |
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" addik %0, r0, 1;" \ |
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" .previous;" \ |
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" .section __ex_table,\"a\";" \ |
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" .word 1b,3b;" \ |
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" .previous;" \ |
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: "=r" (faulted) |
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: "r" (addr), "r" (value) |
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); |
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if (unlikely(faulted)) |
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return -EFAULT; |
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flush_dcache_range(addr, addr + 4); |
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flush_icache_range(addr, addr + 4); |
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return 0; |
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} |
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#define MICROBLAZE_NOP 0x80000000 |
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#define MICROBLAZE_BRI 0xb800000C |
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static unsigned int recorded; /* if save was or not */ |
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static unsigned int imm; /* saving whole imm instruction */ |
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/* There are two approaches howto solve ftrace_make nop function - look below */ |
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#undef USE_FTRACE_NOP |
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#ifdef USE_FTRACE_NOP |
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static unsigned int bralid; /* saving whole bralid instruction */ |
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#endif |
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int ftrace_make_nop(struct module *mod, |
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struct dyn_ftrace *rec, unsigned long addr) |
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{ |
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/* we have this part of code which we are working with |
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* b000c000 imm -16384 |
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* b9fc8e30 bralid r15, -29136 // c0008e30 <_mcount> |
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* 80000000 or r0, r0, r0 |
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* |
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* The first solution (!USE_FTRACE_NOP-could be called branch solution) |
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* b000c000 bri 12 (0xC - jump to any other instruction) |
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* b9fc8e30 bralid r15, -29136 // c0008e30 <_mcount> |
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* 80000000 or r0, r0, r0 |
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* any other instruction |
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* |
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* The second solution (USE_FTRACE_NOP) - no jump just nops |
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* 80000000 or r0, r0, r0 |
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* 80000000 or r0, r0, r0 |
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* 80000000 or r0, r0, r0 |
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*/ |
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int ret = 0; |
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if (recorded == 0) { |
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recorded = 1; |
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imm = *(unsigned int *)rec->ip; |
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pr_debug("%s: imm:0x%x\n", __func__, imm); |
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#ifdef USE_FTRACE_NOP |
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bralid = *(unsigned int *)(rec->ip + 4); |
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pr_debug("%s: bralid 0x%x\n", __func__, bralid); |
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#endif /* USE_FTRACE_NOP */ |
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} |
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#ifdef USE_FTRACE_NOP |
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ret = ftrace_modify_code(rec->ip, MICROBLAZE_NOP); |
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ret += ftrace_modify_code(rec->ip + 4, MICROBLAZE_NOP); |
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#else /* USE_FTRACE_NOP */ |
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ret = ftrace_modify_code(rec->ip, MICROBLAZE_BRI); |
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#endif /* USE_FTRACE_NOP */ |
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return ret; |
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} |
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/* I believe that first is called ftrace_make_nop before this function */ |
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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; |
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pr_debug("%s: addr:0x%x, rec->ip: 0x%x, imm:0x%x\n", |
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__func__, (unsigned int)addr, (unsigned int)rec->ip, imm); |
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ret = ftrace_modify_code(rec->ip, imm); |
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#ifdef USE_FTRACE_NOP |
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pr_debug("%s: bralid:0x%x\n", __func__, bralid); |
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ret += ftrace_modify_code(rec->ip + 4, bralid); |
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#endif /* USE_FTRACE_NOP */ |
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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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int ftrace_update_ftrace_func(ftrace_func_t func) |
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{ |
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unsigned long ip = (unsigned long)(&ftrace_call); |
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unsigned int upper = (unsigned int)func; |
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unsigned int lower = (unsigned int)func; |
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int ret = 0; |
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/* create proper saving to ftrace_call poll */ |
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upper = 0xb0000000 + (upper >> 16); /* imm func_upper */ |
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lower = 0x32800000 + (lower & 0xFFFF); /* addik r20, r0, func_lower */ |
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pr_debug("%s: func=0x%x, ip=0x%x, upper=0x%x, lower=0x%x\n", |
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__func__, (unsigned int)func, (unsigned int)ip, upper, lower); |
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/* save upper and lower code */ |
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ret = ftrace_modify_code(ip, upper); |
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ret += ftrace_modify_code(ip + 4, lower); |
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/* We just need to replace the rtsd r15, 8 with NOP */ |
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ret += ftrace_modify_code((unsigned long)&ftrace_caller, |
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MICROBLAZE_NOP); |
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return ret; |
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} |
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER |
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unsigned int old_jump; /* saving place for jump instruction */ |
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int ftrace_enable_ftrace_graph_caller(void) |
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{ |
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unsigned int ret; |
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unsigned long ip = (unsigned long)(&ftrace_call_graph); |
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old_jump = *(unsigned int *)ip; /* save jump over instruction */ |
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ret = ftrace_modify_code(ip, MICROBLAZE_NOP); |
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pr_debug("%s: Replace instruction: 0x%x\n", __func__, old_jump); |
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return ret; |
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} |
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int ftrace_disable_ftrace_graph_caller(void) |
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{ |
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unsigned int ret; |
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unsigned long ip = (unsigned long)(&ftrace_call_graph); |
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ret = ftrace_modify_code(ip, old_jump); |
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pr_debug("%s\n", __func__); |
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return ret; |
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} |
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#endif /* CONFIG_FUNCTION_GRAPH_TRACER */ |
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#endif /* CONFIG_DYNAMIC_FTRACE */
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