Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 209 insertions, 0 deletions

diff --git a/arch/riscv/kernel/ftrace.c b/arch/riscv/kernel/ftrace.c
new file mode 100644
index 000000000..03a6434a8
--- /dev/null
+++ b/arch/riscv/kernel/ftrace.c
@@ -0,0 +1,209 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2013 Linaro Limited
+ * Author: AKASHI Takahiro <takahiro.akashi@linaro.org>
+ * Copyright (C) 2017 Andes Technology Corporation
+ */
+
+#include <linux/ftrace.h>
+#include <linux/uaccess.h>
+#include <linux/memory.h>
+#include <asm/cacheflush.h>
+#include <asm/patch.h>
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+void ftrace_arch_code_modify_prepare(void) __acquires(&text_mutex)
+{
+	mutex_lock(&text_mutex);
+
+	/*
+	 * The code sequences we use for ftrace can't be patched while the
+	 * kernel is running, so we need to use stop_machine() to modify them
+	 * for now.  This doesn't play nice with text_mutex, we use this flag
+	 * to elide the check.
+	 */
+	riscv_patch_in_stop_machine = true;
+}
+
+void ftrace_arch_code_modify_post_process(void) __releases(&text_mutex)
+{
+	riscv_patch_in_stop_machine = false;
+	mutex_unlock(&text_mutex);
+}
+
+static int ftrace_check_current_call(unsigned long hook_pos,
+				     unsigned int *expected)
+{
+	unsigned int replaced[2];
+	unsigned int nops[2] = {NOP4, NOP4};
+
+	/* we expect nops at the hook position */
+	if (!expected)
+		expected = nops;
+
+	/*
+	 * Read the text we want to modify;
+	 * return must be -EFAULT on read error
+	 */
+	if (copy_from_kernel_nofault(replaced, (void *)hook_pos,
+			MCOUNT_INSN_SIZE))
+		return -EFAULT;
+
+	/*
+	 * Make sure it is what we expect it to be;
+	 * return must be -EINVAL on failed comparison
+	 */
+	if (memcmp(expected, replaced, sizeof(replaced))) {
+		pr_err("%p: expected (%08x %08x) but got (%08x %08x)\n",
+		       (void *)hook_pos, expected[0], expected[1], replaced[0],
+		       replaced[1]);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int __ftrace_modify_call(unsigned long hook_pos, unsigned long target,
+				bool enable, bool ra)
+{
+	unsigned int call[2];
+	unsigned int nops[2] = {NOP4, NOP4};
+
+	if (ra)
+		make_call_ra(hook_pos, target, call);
+	else
+		make_call_t0(hook_pos, target, call);
+
+	/* Replace the auipc-jalr pair at once. Return -EPERM on write error. */
+	if (patch_text_nosync
+	    ((void *)hook_pos, enable ? call : nops, MCOUNT_INSN_SIZE))
+		return -EPERM;
+
+	return 0;
+}
+
+int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
+{
+	unsigned int call[2];
+
+	make_call_t0(rec->ip, addr, call);
+
+	if (patch_text_nosync((void *)rec->ip, call, MCOUNT_INSN_SIZE))
+		return -EPERM;
+
+	return 0;
+}
+
+int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec,
+		    unsigned long addr)
+{
+	unsigned int nops[2] = {NOP4, NOP4};
+
+	if (patch_text_nosync((void *)rec->ip, nops, MCOUNT_INSN_SIZE))
+		return -EPERM;
+
+	return 0;
+}
+
+/*
+ * This is called early on, and isn't wrapped by
+ * ftrace_arch_code_modify_{prepare,post_process}() and therefor doesn't hold
+ * text_mutex, which triggers a lockdep failure.  SMP isn't running so we could
+ * just directly poke the text, but it's simpler to just take the lock
+ * ourselves.
+ */
+int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec)
+{
+	int out;
+
+	mutex_lock(&text_mutex);
+	out = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
+	mutex_unlock(&text_mutex);
+
+	return out;
+}
+
+int ftrace_update_ftrace_func(ftrace_func_t func)
+{
+	int ret = __ftrace_modify_call((unsigned long)&ftrace_call,
+				       (unsigned long)func, true, true);
+	if (!ret) {
+		ret = __ftrace_modify_call((unsigned long)&ftrace_regs_call,
+					   (unsigned long)func, true, true);
+	}
+
+	return ret;
+}
+#endif
+
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
+int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
+		       unsigned long addr)
+{
+	unsigned int call[2];
+	unsigned long caller = rec->ip;
+	int ret;
+
+	make_call_t0(caller, old_addr, call);
+	ret = ftrace_check_current_call(caller, call);
+
+	if (ret)
+		return ret;
+
+	return __ftrace_modify_call(caller, addr, true, false);
+}
+#endif
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+/*
+ * Most of this function is copied from arm64.
+ */
+void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
+			   unsigned long frame_pointer)
+{
+	unsigned long return_hooker = (unsigned long)&return_to_handler;
+	unsigned long old;
+
+	if (unlikely(atomic_read(&current->tracing_graph_pause)))
+		return;
+
+	/*
+	 * We don't suffer access faults, so no extra fault-recovery assembly
+	 * is needed here.
+	 */
+	old = *parent;
+
+	if (!function_graph_enter(old, self_addr, frame_pointer, parent))
+		*parent = return_hooker;
+}
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+extern void ftrace_graph_call(void);
+extern void ftrace_graph_regs_call(void);
+int ftrace_enable_ftrace_graph_caller(void)
+{
+	int ret;
+
+	ret = __ftrace_modify_call((unsigned long)&ftrace_graph_call,
+				    (unsigned long)&prepare_ftrace_return, true, true);
+	if (ret)
+		return ret;
+
+	return __ftrace_modify_call((unsigned long)&ftrace_graph_regs_call,
+				    (unsigned long)&prepare_ftrace_return, true, true);
+}
+
+int ftrace_disable_ftrace_graph_caller(void)
+{
+	int ret;
+
+	ret = __ftrace_modify_call((unsigned long)&ftrace_graph_call,
+				    (unsigned long)&prepare_ftrace_return, false, true);
+	if (ret)
+		return ret;
+
+	return __ftrace_modify_call((unsigned long)&ftrace_graph_regs_call,
+				    (unsigned long)&prepare_ftrace_return, false, true);
+}
+#endif /* CONFIG_DYNAMIC_FTRACE */
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */