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2024-02-20 102a0743326a03cd1a1202ceda21e175b7d3575c

 kernel/arch/s390/kernel/ftrace.c
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@@ -73,31 +73,6 @@
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 #endif
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 }
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-static inline int is_kprobe_on_ftrace(struct ftrace_insn *insn)
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-{
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-#ifdef CONFIG_KPROBES
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-	if (insn->opc == BREAKPOINT_INSTRUCTION)
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-		return 1;
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-#endif
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-	return 0;
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-}
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-
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-static inline void ftrace_generate_kprobe_nop_insn(struct ftrace_insn *insn)
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-{
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-#ifdef CONFIG_KPROBES
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-	insn->opc = BREAKPOINT_INSTRUCTION;
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-	insn->disp = KPROBE_ON_FTRACE_NOP;
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-#endif
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-}
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-
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-static inline void ftrace_generate_kprobe_call_insn(struct ftrace_insn *insn)
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-{
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-#ifdef CONFIG_KPROBES
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-	insn->opc = BREAKPOINT_INSTRUCTION;
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-	insn->disp = KPROBE_ON_FTRACE_CALL;
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-#endif
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-}
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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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@@ -109,22 +84,12 @@
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 {
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 	struct ftrace_insn orig, new, old;
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-	if (probe_kernel_read(&old, (void *) rec->ip, sizeof(old)))
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+	if (copy_from_kernel_nofault(&old, (void *) rec->ip, sizeof(old)))
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 		return -EFAULT;
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 	if (addr == MCOUNT_ADDR) {
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 		/* Initial code replacement */
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 		ftrace_generate_orig_insn(&orig);
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 		ftrace_generate_nop_insn(&new);
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-	} else if (is_kprobe_on_ftrace(&old)) {
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-		/*
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-		 * If we find a breakpoint instruction, a kprobe has been
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-		 * placed at the beginning of the function. We write the
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-		 * constant KPROBE_ON_FTRACE_NOP into the remaining four
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-		 * bytes of the original instruction so that the kprobes
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-		 * handler can execute a nop, if it reaches this breakpoint.
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-		 */
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-		ftrace_generate_kprobe_call_insn(&orig);
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-		ftrace_generate_kprobe_nop_insn(&new);
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 	} else {
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 		/* Replace ftrace call with a nop. */
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 		ftrace_generate_call_insn(&orig, rec->ip);
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@@ -141,23 +106,12 @@
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 {
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 	struct ftrace_insn orig, new, old;
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-	if (probe_kernel_read(&old, (void *) rec->ip, sizeof(old)))
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+	if (copy_from_kernel_nofault(&old, (void *) rec->ip, sizeof(old)))
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 		return -EFAULT;
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-	if (is_kprobe_on_ftrace(&old)) {
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-		/*
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-		 * If we find a breakpoint instruction, a kprobe has been
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-		 * placed at the beginning of the function. We write the
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-		 * constant KPROBE_ON_FTRACE_CALL into the remaining four
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-		 * bytes of the original instruction so that the kprobes
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-		 * handler can execute a brasl if it reaches this breakpoint.
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-		 */
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-		ftrace_generate_kprobe_nop_insn(&orig);
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-		ftrace_generate_kprobe_call_insn(&new);
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-	} else {
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-		/* Replace nop with an ftrace call. */
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-		ftrace_generate_nop_insn(&orig);
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-		ftrace_generate_call_insn(&new, rec->ip);
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-	}
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+	/* Replace nop with an ftrace call. */
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+	ftrace_generate_nop_insn(&orig);
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+	ftrace_generate_call_insn(&new, rec->ip);
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+
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 	/* Verify that the to be replaced code matches what we expect. */
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 	if (memcmp(&orig, &old, sizeof(old)))
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 		return -EINVAL;
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@@ -203,17 +157,18 @@
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  * Hook the return address and push it in the stack of return addresses
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  * in current thread info.
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  */
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-unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip)
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+unsigned long prepare_ftrace_return(unsigned long ra, unsigned long sp,
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+				    unsigned long ip)
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 {
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 	if (unlikely(ftrace_graph_is_dead()))
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 		goto out;
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 	if (unlikely(atomic_read(&current->tracing_graph_pause)))
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 		goto out;
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 	ip -= MCOUNT_INSN_SIZE;
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-	if (!function_graph_enter(parent, ip, 0, NULL))
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-		parent = (unsigned long) return_to_handler;
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+	if (!function_graph_enter(ra, ip, 0, (void *) sp))
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+		ra = (unsigned long) return_to_handler;
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 out:
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-	return parent;
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+	return ra;
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 }
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 NOKPROBE_SYMBOL(prepare_ftrace_return);
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@@ -242,3 +197,45 @@
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 }
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 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
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+
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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 pt_regs *regs)
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+{
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+	struct kprobe_ctlblk *kcb;
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+	struct kprobe *p = get_kprobe((kprobe_opcode_t *)ip);
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+
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+	if (unlikely(!p) || kprobe_disabled(p))
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+		return;
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+
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+	if (kprobe_running()) {
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+		kprobes_inc_nmissed_count(p);
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+		return;
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+	}
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+
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+	__this_cpu_write(current_kprobe, p);
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+
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+	kcb = get_kprobe_ctlblk();
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+	kcb->kprobe_status = KPROBE_HIT_ACTIVE;
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+
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+	instruction_pointer_set(regs, ip);
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+
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+	if (!p->pre_handler || !p->pre_handler(p, regs)) {
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+
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+		instruction_pointer_set(regs, ip + MCOUNT_INSN_SIZE);
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+
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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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+}
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+NOKPROBE_SYMBOL(kprobe_ftrace_handler);
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+
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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