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@@ -16,11 +16,13 @@
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#include <linux/string.h>
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#include <linux/init.h>
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#include <linux/io.h>
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+#include <linux/kernel.h>
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#include <asm/ftrace.h>
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#include <asm/cacheflush.h>
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#include <asm/unistd.h>
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#include <trace/syscall.h>
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+#ifdef CONFIG_DYNAMIC_FTRACE
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static unsigned char ftrace_replaced_code[MCOUNT_INSN_SIZE];
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static unsigned char ftrace_nop[4];
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@@ -133,6 +135,126 @@ int __init ftrace_dyn_arch_init(void *data)
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return 0;
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}
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+#endif /* CONFIG_DYNAMIC_FTRACE */
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+
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+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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+#ifdef CONFIG_DYNAMIC_FTRACE
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+extern void ftrace_graph_call(void);
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+
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+static int ftrace_mod(unsigned long ip, unsigned long old_addr,
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+ unsigned long new_addr)
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+{
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+ unsigned char code[MCOUNT_INSN_SIZE];
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+
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+ if (probe_kernel_read(code, (void *)ip, MCOUNT_INSN_SIZE))
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+ return -EFAULT;
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+
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+ if (old_addr != __raw_readl((unsigned long *)code))
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+ return -EINVAL;
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+
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+ __raw_writel(new_addr, ip);
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+ return 0;
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+}
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+
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+int ftrace_enable_ftrace_graph_caller(void)
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+{
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+ unsigned long ip, old_addr, new_addr;
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+
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+ ip = (unsigned long)(&ftrace_graph_call) + GRAPH_INSN_OFFSET;
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+ old_addr = (unsigned long)(&skip_trace);
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+ new_addr = (unsigned long)(&ftrace_graph_caller);
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+
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+ return ftrace_mod(ip, old_addr, new_addr);
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+}
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+
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+int ftrace_disable_ftrace_graph_caller(void)
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+{
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+ unsigned long ip, old_addr, new_addr;
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+
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+ ip = (unsigned long)(&ftrace_graph_call) + GRAPH_INSN_OFFSET;
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+ old_addr = (unsigned long)(&ftrace_graph_caller);
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+ new_addr = (unsigned long)(&skip_trace);
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+
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+ return ftrace_mod(ip, old_addr, new_addr);
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+}
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+#endif /* CONFIG_DYNAMIC_FTRACE */
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+
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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 the current thread info.
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+ *
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+ * This is the main routine for the function graph tracer. The function
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+ * graph tracer essentially works like this:
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+ *
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+ * parent is the stack address containing self_addr's return address.
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+ * We pull the real return address out of parent and store it in
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+ * current's ret_stack. Then, we replace the return address on the stack
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+ * with the address of return_to_handler. self_addr is the function that
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+ * called mcount.
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+ *
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+ * When self_addr returns, it will jump to return_to_handler which calls
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+ * ftrace_return_to_handler. ftrace_return_to_handler will pull the real
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+ * return address off of current's ret_stack and jump to it.
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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, err;
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+ struct ftrace_graph_ent trace;
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+ unsigned long return_hooker = (unsigned long)&return_to_handler;
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+
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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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+ /*
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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__(
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+ "1: \n\t"
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+ "mov.l @%2, %0 \n\t"
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+ "2: \n\t"
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+ "mov.l %3, @%2 \n\t"
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+ "mov #0, %1 \n\t"
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+ "3: \n\t"
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+ ".section .fixup, \"ax\" \n\t"
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+ "4: \n\t"
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+ "mov.l 5f, %0 \n\t"
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+ "jmp @%0 \n\t"
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+ " mov #1, %1 \n\t"
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+ ".balign 4 \n\t"
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+ "5: .long 3b \n\t"
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+ ".previous \n\t"
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+ ".section __ex_table,\"a\" \n\t"
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+ ".long 1b, 4b \n\t"
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+ ".long 2b, 4b \n\t"
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+ ".previous \n\t"
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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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+
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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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+
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+ err = ftrace_push_return_trace(old, self_addr, &trace.depth, 0);
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+ if (err == -EBUSY) {
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+ __raw_writel(old, parent);
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+ return;
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+ }
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+
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+ trace.func = self_addr;
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+
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+ /* Only trace if the calling function expects to */
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+ if (!ftrace_graph_entry(&trace)) {
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+ current->curr_ret_stack--;
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+ __raw_writel(old, parent);
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+ }
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+}
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+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
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#ifdef CONFIG_FTRACE_SYSCALLS
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Matt Fleming