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