Initial import

1 files changed, 233 insertions, 0 deletions

diff --git a/arch/microblaze/kernel/ftrace.c b/arch/microblaze/kernel/ftrace.c
new file mode 100644
index 000000000..fc7b48a52
--- /dev/null
+++ b/arch/microblaze/kernel/ftrace.c
@@ -0,0 +1,233 @@
+/*
+ * Ftrace support for Microblaze.
+ *
+ * Copyright (C) 2009 Michal Simek <monstr@monstr.eu>
+ * Copyright (C) 2009 PetaLogix
+ *
+ * Based on MIPS and PowerPC ftrace code
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#include <asm/cacheflush.h>
+#include <linux/ftrace.h>
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+/*
+ * Hook the return address and push it in the stack of return addrs
+ * in current thread info.
+ */
+void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
+{
+	unsigned long old;
+	int faulted, err;
+	struct ftrace_graph_ent trace;
+	unsigned long return_hooker = (unsigned long)
+				&return_to_handler;
+
+	if (unlikely(ftrace_graph_is_dead()))
+		return;
+
+	if (unlikely(atomic_read(&current->tracing_graph_pause)))
+		return;
+
+	/*
+	 * Protect against fault, even if it shouldn't
+	 * happen. This tool is too much intrusive to
+	 * ignore such a protection.
+	 */
+	asm volatile("	1:	lwi	%0, %2, 0;"		\
+			"2:	swi	%3, %2, 0;"		\
+			"	addik	%1, r0, 0;"		\
+			"3:"					\
+			"	.section .fixup, \"ax\";"	\
+			"4:	brid	3b;"			\
+			"	addik	%1, r0, 1;"		\
+			"	.previous;"			\
+			"	.section __ex_table,\"a\";"	\
+			"	.word	1b,4b;"			\
+			"	.word	2b,4b;"			\
+			"	.previous;"			\
+			: "=&r" (old), "=r" (faulted)
+			: "r" (parent), "r" (return_hooker)
+	);
+
+	flush_dcache_range((u32)parent, (u32)parent + 4);
+	flush_icache_range((u32)parent, (u32)parent + 4);
+
+	if (unlikely(faulted)) {
+		ftrace_graph_stop();
+		WARN_ON(1);
+		return;
+	}
+
+	err = ftrace_push_return_trace(old, self_addr, &trace.depth, 0);
+	if (err == -EBUSY) {
+		*parent = old;
+		return;
+	}
+
+	trace.func = self_addr;
+	/* Only trace if the calling function expects to */
+	if (!ftrace_graph_entry(&trace)) {
+		current->curr_ret_stack--;
+		*parent = old;
+	}
+}
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+/* save value to addr - it is save to do it in asm */
+static int ftrace_modify_code(unsigned long addr, unsigned int value)
+{
+	int faulted = 0;
+
+	__asm__ __volatile__("	1:	swi	%2, %1, 0;"		\
+				"	addik	%0, r0, 0;"		\
+				"2:"					\
+				"	.section .fixup, \"ax\";"	\
+				"3:	brid	2b;"			\
+				"	addik	%0, r0, 1;"		\
+				"	.previous;"			\
+				"	.section __ex_table,\"a\";"	\
+				"	.word	1b,3b;"			\
+				"	.previous;"			\
+				: "=r" (faulted)
+				: "r" (addr), "r" (value)
+	);
+
+	if (unlikely(faulted))
+		return -EFAULT;
+
+	flush_dcache_range(addr, addr + 4);
+	flush_icache_range(addr, addr + 4);
+
+	return 0;
+}
+
+#define MICROBLAZE_NOP 0x80000000
+#define MICROBLAZE_BRI 0xb800000C
+
+static unsigned int recorded; /* if save was or not */
+static unsigned int imm; /* saving whole imm instruction */
+
+/* There are two approaches howto solve ftrace_make nop function - look below */
+#undef USE_FTRACE_NOP
+
+#ifdef USE_FTRACE_NOP
+static unsigned int bralid; /* saving whole bralid instruction */
+#endif
+
+int ftrace_make_nop(struct module *mod,
+			struct dyn_ftrace *rec, unsigned long addr)
+{
+	/* we have this part of code which we are working with
+	 * b000c000        imm     -16384
+	 * b9fc8e30        bralid  r15, -29136     // c0008e30 <_mcount>
+	 * 80000000        or      r0, r0, r0
+	 *
+	 * The first solution (!USE_FTRACE_NOP-could be called branch solution)
+	 * b000c000        bri	12 (0xC - jump to any other instruction)
+	 * b9fc8e30        bralid  r15, -29136     // c0008e30 <_mcount>
+	 * 80000000        or      r0, r0, r0
+	 * any other instruction
+	 *
+	 * The second solution (USE_FTRACE_NOP) - no jump just nops
+	 * 80000000        or      r0, r0, r0
+	 * 80000000        or      r0, r0, r0
+	 * 80000000        or      r0, r0, r0
+	 */
+	int ret = 0;
+
+	if (recorded == 0) {
+		recorded = 1;
+		imm = *(unsigned int *)rec->ip;
+		pr_debug("%s: imm:0x%x\n", __func__, imm);
+#ifdef USE_FTRACE_NOP
+		bralid = *(unsigned int *)(rec->ip + 4);
+		pr_debug("%s: bralid 0x%x\n", __func__, bralid);
+#endif /* USE_FTRACE_NOP */
+	}
+
+#ifdef USE_FTRACE_NOP
+	ret = ftrace_modify_code(rec->ip, MICROBLAZE_NOP);
+	ret += ftrace_modify_code(rec->ip + 4, MICROBLAZE_NOP);
+#else /* USE_FTRACE_NOP */
+	ret = ftrace_modify_code(rec->ip, MICROBLAZE_BRI);
+#endif /* USE_FTRACE_NOP */
+	return ret;
+}
+
+/* I believe that first is called ftrace_make_nop before this function */
+int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
+{
+	int ret;
+	pr_debug("%s: addr:0x%x, rec->ip: 0x%x, imm:0x%x\n",
+		__func__, (unsigned int)addr, (unsigned int)rec->ip, imm);
+	ret = ftrace_modify_code(rec->ip, imm);
+#ifdef USE_FTRACE_NOP
+	pr_debug("%s: bralid:0x%x\n", __func__, bralid);
+	ret += ftrace_modify_code(rec->ip + 4, bralid);
+#endif /* USE_FTRACE_NOP */
+	return ret;
+}
+
+int __init ftrace_dyn_arch_init(void)
+{
+	return 0;
+}
+
+int ftrace_update_ftrace_func(ftrace_func_t func)
+{
+	unsigned long ip = (unsigned long)(&ftrace_call);
+	unsigned int upper = (unsigned int)func;
+	unsigned int lower = (unsigned int)func;
+	int ret = 0;
+
+	/* create proper saving to ftrace_call poll */
+	upper = 0xb0000000 + (upper >> 16); /* imm func_upper */
+	lower = 0x32800000 + (lower & 0xFFFF); /* addik r20, r0, func_lower */
+
+	pr_debug("%s: func=0x%x, ip=0x%x, upper=0x%x, lower=0x%x\n",
+		__func__, (unsigned int)func, (unsigned int)ip, upper, lower);
+
+	/* save upper and lower code */
+	ret = ftrace_modify_code(ip, upper);
+	ret += ftrace_modify_code(ip + 4, lower);
+
+	/* We just need to replace the rtsd r15, 8 with NOP */
+	ret += ftrace_modify_code((unsigned long)&ftrace_caller,
+				  MICROBLAZE_NOP);
+
+	return ret;
+}
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+unsigned int old_jump; /* saving place for jump instruction */
+
+int ftrace_enable_ftrace_graph_caller(void)
+{
+	unsigned int ret;
+	unsigned long ip = (unsigned long)(&ftrace_call_graph);
+
+	old_jump = *(unsigned int *)ip; /* save jump over instruction */
+	ret = ftrace_modify_code(ip, MICROBLAZE_NOP);
+
+	pr_debug("%s: Replace instruction: 0x%x\n", __func__, old_jump);
+	return ret;
+}
+
+int ftrace_disable_ftrace_graph_caller(void)
+{
+	unsigned int ret;
+	unsigned long ip = (unsigned long)(&ftrace_call_graph);
+
+	ret = ftrace_modify_code(ip, old_jump);
+
+	pr_debug("%s\n", __func__);
+	return ret;
+}
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
+#endif /* CONFIG_DYNAMIC_FTRACE */