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258 lines
5.7 KiB
258 lines
5.7 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Code for tracing calls in Linux kernel. |
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* Copyright (C) 2009-2016 Helge Deller <[email protected]> |
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* |
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* based on code for x86 which is: |
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* Copyright (C) 2007-2008 Steven Rostedt <[email protected]> |
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* |
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* future possible enhancements: |
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* - add CONFIG_STACK_TRACER |
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*/ |
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#include <linux/init.h> |
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#include <linux/ftrace.h> |
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#include <linux/uaccess.h> |
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#include <linux/kprobes.h> |
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#include <linux/ptrace.h> |
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#include <asm/assembly.h> |
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#include <asm/sections.h> |
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#include <asm/ftrace.h> |
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#include <asm/patch.h> |
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#define __hot __section(".text.hot") |
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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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static void __hot prepare_ftrace_return(unsigned long *parent, |
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unsigned long self_addr) |
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{ |
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unsigned long old; |
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extern int parisc_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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old = *parent; |
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if (!function_graph_enter(old, self_addr, 0, NULL)) |
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/* activate parisc_return_to_handler() as return point */ |
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*parent = (unsigned long) &parisc_return_to_handler; |
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} |
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#endif /* CONFIG_FUNCTION_GRAPH_TRACER */ |
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void notrace __hot ftrace_function_trampoline(unsigned long parent, |
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unsigned long self_addr, |
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unsigned long org_sp_gr3, |
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struct ftrace_regs *fregs) |
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{ |
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#ifndef CONFIG_DYNAMIC_FTRACE |
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extern ftrace_func_t ftrace_trace_function; |
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#endif |
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extern struct ftrace_ops *function_trace_op; |
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if (function_trace_op->flags & FTRACE_OPS_FL_ENABLED && |
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ftrace_trace_function != ftrace_stub) |
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ftrace_trace_function(self_addr, parent, |
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function_trace_op, fregs); |
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER |
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if (dereference_function_descriptor(ftrace_graph_return) != |
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dereference_function_descriptor(ftrace_stub) || |
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ftrace_graph_entry != ftrace_graph_entry_stub) { |
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unsigned long *parent_rp; |
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/* calculate pointer to %rp in stack */ |
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parent_rp = (unsigned long *) (org_sp_gr3 - RP_OFFSET); |
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/* sanity check: parent_rp should hold parent */ |
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if (*parent_rp != parent) |
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return; |
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prepare_ftrace_return(parent_rp, self_addr); |
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return; |
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} |
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#endif |
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} |
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER |
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int ftrace_enable_ftrace_graph_caller(void) |
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{ |
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return 0; |
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} |
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int ftrace_disable_ftrace_graph_caller(void) |
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{ |
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return 0; |
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} |
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#endif |
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#ifdef CONFIG_DYNAMIC_FTRACE |
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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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return 0; |
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} |
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int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, |
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unsigned long addr) |
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{ |
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return 0; |
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} |
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unsigned long ftrace_call_adjust(unsigned long addr) |
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{ |
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return addr+(FTRACE_PATCHABLE_FUNCTION_SIZE-1)*4; |
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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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u32 insn[FTRACE_PATCHABLE_FUNCTION_SIZE]; |
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u32 *tramp; |
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int size, ret, i; |
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void *ip; |
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#ifdef CONFIG_64BIT |
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unsigned long addr2 = |
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(unsigned long)dereference_function_descriptor((void *)addr); |
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u32 ftrace_trampoline[] = { |
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0x73c10208, /* std,ma r1,100(sp) */ |
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0x0c2110c1, /* ldd -10(r1),r1 */ |
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0xe820d002, /* bve,n (r1) */ |
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addr2 >> 32, |
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addr2 & 0xffffffff, |
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0xe83f1fd7, /* b,l,n .-14,r1 */ |
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}; |
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u32 ftrace_trampoline_unaligned[] = { |
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addr2 >> 32, |
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addr2 & 0xffffffff, |
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0x37de0200, /* ldo 100(sp),sp */ |
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0x73c13e01, /* std r1,-100(sp) */ |
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0x34213ff9, /* ldo -4(r1),r1 */ |
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0x50213fc1, /* ldd -20(r1),r1 */ |
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0xe820d002, /* bve,n (r1) */ |
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0xe83f1fcf, /* b,l,n .-20,r1 */ |
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}; |
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BUILD_BUG_ON(ARRAY_SIZE(ftrace_trampoline_unaligned) > |
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FTRACE_PATCHABLE_FUNCTION_SIZE); |
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#else |
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u32 ftrace_trampoline[] = { |
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(u32)addr, |
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0x6fc10080, /* stw,ma r1,40(sp) */ |
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0x48213fd1, /* ldw -18(r1),r1 */ |
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0xe820c002, /* bv,n r0(r1) */ |
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0xe83f1fdf, /* b,l,n .-c,r1 */ |
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}; |
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#endif |
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BUILD_BUG_ON(ARRAY_SIZE(ftrace_trampoline) > |
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FTRACE_PATCHABLE_FUNCTION_SIZE); |
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size = sizeof(ftrace_trampoline); |
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tramp = ftrace_trampoline; |
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#ifdef CONFIG_64BIT |
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if (rec->ip & 0x4) { |
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size = sizeof(ftrace_trampoline_unaligned); |
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tramp = ftrace_trampoline_unaligned; |
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} |
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#endif |
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ip = (void *)(rec->ip + 4 - size); |
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ret = copy_from_kernel_nofault(insn, ip, size); |
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if (ret) |
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return ret; |
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for (i = 0; i < size / 4; i++) { |
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if (insn[i] != INSN_NOP) |
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return -EINVAL; |
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} |
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__patch_text_multiple(ip, tramp, size); |
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return 0; |
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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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u32 insn[FTRACE_PATCHABLE_FUNCTION_SIZE]; |
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int i; |
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for (i = 0; i < ARRAY_SIZE(insn); i++) |
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insn[i] = INSN_NOP; |
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__patch_text((void *)rec->ip, INSN_NOP); |
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__patch_text_multiple((void *)rec->ip + 4 - sizeof(insn), |
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insn, sizeof(insn)-4); |
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return 0; |
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} |
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#endif |
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#ifdef CONFIG_KPROBES_ON_FTRACE |
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void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip, |
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struct ftrace_ops *ops, struct ftrace_regs *fregs) |
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{ |
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struct kprobe_ctlblk *kcb; |
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struct pt_regs *regs; |
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struct kprobe *p; |
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int bit; |
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bit = ftrace_test_recursion_trylock(ip, parent_ip); |
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if (bit < 0) |
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return; |
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regs = ftrace_get_regs(fregs); |
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preempt_disable_notrace(); |
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p = get_kprobe((kprobe_opcode_t *)ip); |
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if (unlikely(!p) || kprobe_disabled(p)) |
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goto out; |
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if (kprobe_running()) { |
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kprobes_inc_nmissed_count(p); |
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goto out; |
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} |
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__this_cpu_write(current_kprobe, p); |
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kcb = get_kprobe_ctlblk(); |
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kcb->kprobe_status = KPROBE_HIT_ACTIVE; |
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regs->iaoq[0] = ip; |
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regs->iaoq[1] = ip + 4; |
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if (!p->pre_handler || !p->pre_handler(p, regs)) { |
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regs->iaoq[0] = ip + 4; |
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regs->iaoq[1] = ip + 8; |
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if (unlikely(p->post_handler)) { |
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kcb->kprobe_status = KPROBE_HIT_SSDONE; |
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p->post_handler(p, regs, 0); |
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} |
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} |
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__this_cpu_write(current_kprobe, NULL); |
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out: |
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preempt_enable_notrace(); |
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ftrace_test_recursion_unlock(bit); |
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} |
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NOKPROBE_SYMBOL(kprobe_ftrace_handler); |
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int arch_prepare_kprobe_ftrace(struct kprobe *p) |
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{ |
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p->ainsn.insn = NULL; |
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return 0; |
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} |
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#endif
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