Resguardo inicial

linux-7.2.3/arch/powerpc/kernel/trace/Makefile

@@ -0,0 +1,34 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the powerpc trace subsystem
+#
+
+ifdef CONFIG_FUNCTION_TRACER
+# do not trace tracer code
+CFLAGS_REMOVE_ftrace.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_ftrace_64_pg.o = $(CC_FLAGS_FTRACE)
+endif
+
+ifdef CONFIG_FUNCTION_TRACER
+obj32-y					+= ftrace.o ftrace_entry.o
+ifeq ($(CONFIG_MPROFILE_KERNEL)$(CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY),)
+obj64-y					+= ftrace_64_pg.o ftrace_64_pg_entry.o
+else
+obj64-y					+= ftrace.o ftrace_entry.o
+endif
+endif
+
+obj-$(CONFIG_TRACING)			+= trace_clock.o
+
+obj-$(CONFIG_PPC64)			+= $(obj64-y)
+obj-$(CONFIG_PPC32)			+= $(obj32-y)
+
+# Disable GCOV, KCOV & sanitizers in odd or sensitive code
+GCOV_PROFILE_ftrace.o := n
+KCOV_INSTRUMENT_ftrace.o := n
+KCSAN_SANITIZE_ftrace.o := n
+UBSAN_SANITIZE_ftrace.o := n
+GCOV_PROFILE_ftrace_64_pg.o := n
+KCOV_INSTRUMENT_ftrace_64_pg.o := n
+KCSAN_SANITIZE_ftrace_64_pg.o := n
+UBSAN_SANITIZE_ftrace_64_pg.o := n

linux-7.2.3/arch/powerpc/kernel/trace/ftrace.c

@@ -0,0 +1,696 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Code for replacing ftrace calls with jumps.
+ *
+ * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
+ *
+ * Thanks goes out to P.A. Semi, Inc for supplying me with a PPC64 box.
+ *
+ * Added function graph tracer code, taken from x86 that was written
+ * by Frederic Weisbecker, and ported to PPC by Steven Rostedt.
+ *
+ */
+
+#define pr_fmt(fmt) "ftrace-powerpc: " fmt
+
+#include <linux/spinlock.h>
+#include <linux/hardirq.h>
+#include <linux/uaccess.h>
+#include <linux/module.h>
+#include <linux/ftrace.h>
+#include <linux/percpu.h>
+#include <linux/init.h>
+#include <linux/list.h>
+
+#include <asm/cacheflush.h>
+#include <asm/text-patching.h>
+#include <asm/ftrace.h>
+#include <asm/syscall.h>
+#include <asm/inst.h>
+#include <asm/sections.h>
+
+#define	NUM_FTRACE_TRAMPS	2
+static unsigned long ftrace_tramps[NUM_FTRACE_TRAMPS];
+
+unsigned long ftrace_call_adjust(unsigned long addr)
+{
+	if (addr >= (unsigned long)__exittext_begin && addr < (unsigned long)__exittext_end)
+		return 0;
+
+	if (IS_ENABLED(CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY)) {
+		if (!IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE)) {
+			addr += MCOUNT_INSN_SIZE;
+			if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS))
+				addr += MCOUNT_INSN_SIZE;
+		} else if (IS_ENABLED(CONFIG_CC_IS_CLANG) && IS_ENABLED(CONFIG_PPC64)) {
+			/*
+			 * addr points to global entry point though the NOP was emitted at local
+			 * entry point due to https://github.com/llvm/llvm-project/issues/163706
+			 * Handle that here with ppc_function_entry() for kernel symbols while
+			 * adjusting module addresses in the else case, by looking for the below
+			 * module global entry point sequence:
+			 *	ld    r2, -8(r12)
+			 *	add   r2, r2, r12
+			 */
+			if (is_kernel_text(addr) || is_kernel_inittext(addr))
+				addr = ppc_function_entry((void *)addr);
+			else if ((ppc_inst_val(ppc_inst_read((u32 *)addr)) ==
+				  PPC_RAW_LD(_R2, _R12, -8)) &&
+				 (ppc_inst_val(ppc_inst_read((u32 *)(addr+4))) ==
+				  PPC_RAW_ADD(_R2, _R2, _R12)))
+				addr += 8;
+		}
+	}
+
+	return addr;
+}
+
+static ppc_inst_t ftrace_create_branch_inst(unsigned long ip, unsigned long addr, int link)
+{
+	ppc_inst_t op;
+
+	WARN_ON(!is_offset_in_branch_range(addr - ip));
+	create_branch(&op, (u32 *)ip, addr, link ? BRANCH_SET_LINK : 0);
+
+	return op;
+}
+
+static inline int ftrace_read_inst(unsigned long ip, ppc_inst_t *op)
+{
+	if (copy_inst_from_kernel_nofault(op, (void *)ip)) {
+		pr_err("0x%lx: fetching instruction failed\n", ip);
+		return -EFAULT;
+	}
+
+	return 0;
+}
+
+static inline int ftrace_validate_inst(unsigned long ip, ppc_inst_t inst)
+{
+	ppc_inst_t op;
+	int ret;
+
+	ret = ftrace_read_inst(ip, &op);
+	if (!ret && !ppc_inst_equal(op, inst)) {
+		pr_err("0x%lx: expected (%08lx) != found (%08lx)\n",
+		       ip, ppc_inst_as_ulong(inst), ppc_inst_as_ulong(op));
+		ret = -EINVAL;
+	}
+
+	return ret;
+}
+
+static inline int ftrace_modify_code(unsigned long ip, ppc_inst_t old, ppc_inst_t new)
+{
+	int ret = ftrace_validate_inst(ip, old);
+
+	if (!ret && !ppc_inst_equal(old, new))
+		ret = patch_instruction((u32 *)ip, new);
+
+	return ret;
+}
+
+static int is_bl_op(ppc_inst_t op)
+{
+	return (ppc_inst_val(op) & ~PPC_LI_MASK) == PPC_RAW_BL(0);
+}
+
+static unsigned long find_ftrace_tramp(unsigned long ip)
+{
+	int i;
+
+	for (i = 0; i < NUM_FTRACE_TRAMPS; i++)
+		if (!ftrace_tramps[i])
+			continue;
+		else if (is_offset_in_branch_range(ftrace_tramps[i] - ip))
+			return ftrace_tramps[i];
+
+	return 0;
+}
+
+#ifdef CONFIG_MODULES
+static unsigned long ftrace_lookup_module_stub(unsigned long ip, unsigned long addr)
+{
+	struct module *mod = NULL;
+
+	scoped_guard(rcu)
+		mod = __module_text_address(ip);
+	if (!mod)
+		pr_err("No module loaded at addr=%lx\n", ip);
+
+	return (addr == (unsigned long)ftrace_caller ? mod->arch.tramp : mod->arch.tramp_regs);
+}
+#else
+static unsigned long ftrace_lookup_module_stub(unsigned long ip, unsigned long addr)
+{
+	return 0;
+}
+#endif
+
+static unsigned long ftrace_get_ool_stub(struct dyn_ftrace *rec)
+{
+#ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE
+	return rec->arch.ool_stub;
+#else
+	BUILD_BUG();
+#endif
+}
+
+static int ftrace_get_call_inst(struct dyn_ftrace *rec, unsigned long addr, ppc_inst_t *call_inst)
+{
+	unsigned long ip;
+	unsigned long stub;
+
+	if (IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE))
+		ip = ftrace_get_ool_stub(rec) + MCOUNT_INSN_SIZE; /* second instruction in stub */
+	else
+		ip = rec->ip;
+
+	if (!is_offset_in_branch_range(addr - ip) && addr != FTRACE_ADDR &&
+	    addr != FTRACE_REGS_ADDR) {
+		/* This can only happen with ftrace direct */
+		if (!IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS)) {
+			pr_err("0x%lx (0x%lx): Unexpected target address 0x%lx\n",
+			       ip, rec->ip, addr);
+			return -EINVAL;
+		}
+		addr = FTRACE_ADDR;
+	}
+
+	if (is_offset_in_branch_range(addr - ip))
+		/* Within range */
+		stub = addr;
+	else if (core_kernel_text(ip))
+		/* We would be branching to one of our ftrace stubs */
+		stub = find_ftrace_tramp(ip);
+	else
+		stub = ftrace_lookup_module_stub(ip, addr);
+
+	if (!stub) {
+		pr_err("0x%lx (0x%lx): No ftrace stubs reachable\n", ip, rec->ip);
+		return -EINVAL;
+	}
+
+	*call_inst = ftrace_create_branch_inst(ip, stub, 1);
+	return 0;
+}
+
+static int ftrace_init_ool_stub(struct module *mod, struct dyn_ftrace *rec)
+{
+#ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE
+	static int ool_stub_text_index, ool_stub_text_end_index, ool_stub_inittext_index;
+	int ret = 0, ool_stub_count, *ool_stub_index;
+	ppc_inst_t inst;
+	/*
+	 * See ftrace_entry.S if changing the below instruction sequence, as we rely on
+	 * decoding the last branch instruction here to recover the correct function ip.
+	 */
+	struct ftrace_ool_stub *ool_stub, ool_stub_template = {
+		.insn = {
+			PPC_RAW_MFLR(_R0),
+			PPC_RAW_NOP(),		/* bl ftrace_caller */
+			PPC_RAW_MTLR(_R0),
+			PPC_RAW_NOP()		/* b rec->ip + 4 */
+		}
+	};
+
+	WARN_ON(rec->arch.ool_stub);
+
+	if (is_kernel_inittext(rec->ip)) {
+		ool_stub = ftrace_ool_stub_inittext;
+		ool_stub_index = &ool_stub_inittext_index;
+		ool_stub_count = ftrace_ool_stub_inittext_count;
+	} else if (is_kernel_text(rec->ip)) {
+		/*
+		 * ftrace records are sorted, so we first use up the stub area within .text
+		 * (ftrace_ool_stub_text) before using the area at the end of .text
+		 * (ftrace_ool_stub_text_end), unless the stub is out of range of the record.
+		 */
+		if (ool_stub_text_index >= ftrace_ool_stub_text_count ||
+		    !is_offset_in_branch_range((long)rec->ip -
+					       (long)&ftrace_ool_stub_text[ool_stub_text_index])) {
+			ool_stub = ftrace_ool_stub_text_end;
+			ool_stub_index = &ool_stub_text_end_index;
+			ool_stub_count = ftrace_ool_stub_text_end_count;
+		} else {
+			ool_stub = ftrace_ool_stub_text;
+			ool_stub_index = &ool_stub_text_index;
+			ool_stub_count = ftrace_ool_stub_text_count;
+		}
+#ifdef CONFIG_MODULES
+	} else if (mod) {
+		ool_stub = mod->arch.ool_stubs;
+		ool_stub_index = &mod->arch.ool_stub_index;
+		ool_stub_count = mod->arch.ool_stub_count;
+#endif
+	} else {
+		return -EINVAL;
+	}
+
+	ool_stub += (*ool_stub_index)++;
+
+	if (WARN_ON(*ool_stub_index > ool_stub_count))
+		return -EINVAL;
+
+	if (!is_offset_in_branch_range((long)rec->ip - (long)&ool_stub->insn[0]) ||
+	    !is_offset_in_branch_range((long)(rec->ip + MCOUNT_INSN_SIZE) -
+				       (long)&ool_stub->insn[3])) {
+		pr_err("%s: ftrace ool stub out of range (%p -> %p).\n",
+					__func__, (void *)rec->ip, (void *)&ool_stub->insn[0]);
+		return -EINVAL;
+	}
+
+	rec->arch.ool_stub = (unsigned long)&ool_stub->insn[0];
+
+	/* bl ftrace_caller */
+	if (!mod)
+		ret = ftrace_get_call_inst(rec, (unsigned long)ftrace_caller, &inst);
+#ifdef CONFIG_MODULES
+	else
+		/*
+		 * We can't use ftrace_get_call_inst() since that uses
+		 * __module_text_address(rec->ip) to look up the module.
+		 * But, since the module is not fully formed at this stage,
+		 * the lookup fails. We know the target though, so generate
+		 * the branch inst directly.
+		 */
+		inst = ftrace_create_branch_inst(ftrace_get_ool_stub(rec) + MCOUNT_INSN_SIZE,
+						 mod->arch.tramp, 1);
+#endif
+	ool_stub_template.insn[1] = ppc_inst_val(inst);
+
+	/* b rec->ip + 4 */
+	if (!ret && create_branch(&inst, &ool_stub->insn[3], rec->ip + MCOUNT_INSN_SIZE, 0))
+		return -EINVAL;
+	ool_stub_template.insn[3] = ppc_inst_val(inst);
+
+	if (!ret)
+		ret = patch_instructions((u32 *)ool_stub, (u32 *)&ool_stub_template,
+					 sizeof(ool_stub_template), false);
+
+	return ret;
+#else /* !CONFIG_PPC_FTRACE_OUT_OF_LINE */
+	BUILD_BUG();
+#endif
+}
+
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS
+static const struct ftrace_ops *powerpc_rec_get_ops(struct dyn_ftrace *rec)
+{
+	const struct ftrace_ops *ops = NULL;
+
+	if (rec->flags & FTRACE_FL_CALL_OPS_EN) {
+		ops = ftrace_find_unique_ops(rec);
+		WARN_ON_ONCE(!ops);
+	}
+
+	if (!ops)
+		ops = &ftrace_list_ops;
+
+	return ops;
+}
+
+static int ftrace_rec_set_ops(struct dyn_ftrace *rec, const struct ftrace_ops *ops)
+{
+	if (IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE))
+		return patch_ulong((void *)(ftrace_get_ool_stub(rec) - sizeof(unsigned long)),
+				   (unsigned long)ops);
+	else
+		return patch_ulong((void *)(rec->ip - MCOUNT_INSN_SIZE - sizeof(unsigned long)),
+				   (unsigned long)ops);
+}
+
+static int ftrace_rec_set_nop_ops(struct dyn_ftrace *rec)
+{
+	return ftrace_rec_set_ops(rec, &ftrace_nop_ops);
+}
+
+static int ftrace_rec_update_ops(struct dyn_ftrace *rec)
+{
+	return ftrace_rec_set_ops(rec, powerpc_rec_get_ops(rec));
+}
+#else
+static int ftrace_rec_set_nop_ops(struct dyn_ftrace *rec) { return 0; }
+static int ftrace_rec_update_ops(struct dyn_ftrace *rec) { return 0; }
+#endif
+
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
+int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, unsigned long addr)
+{
+	/* This should never be called since we override ftrace_replace_code() */
+	WARN_ON(1);
+	return -EINVAL;
+}
+#endif
+
+int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
+{
+	ppc_inst_t old, new;
+	unsigned long ip = rec->ip;
+	int ret = 0;
+
+	/* This can only ever be called during module load */
+	if (WARN_ON(!IS_ENABLED(CONFIG_MODULES) || core_kernel_text(ip)))
+		return -EINVAL;
+
+	old = ppc_inst(PPC_RAW_NOP());
+	if (IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE)) {
+		ip = ftrace_get_ool_stub(rec) + MCOUNT_INSN_SIZE; /* second instruction in stub */
+		ret = ftrace_get_call_inst(rec, (unsigned long)ftrace_caller, &old);
+	}
+
+	ret |= ftrace_get_call_inst(rec, addr, &new);
+
+	if (!ret)
+		ret = ftrace_modify_code(ip, old, new);
+
+	ret = ftrace_rec_update_ops(rec);
+	if (ret)
+		return ret;
+
+	if (!ret && IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE))
+		ret = ftrace_modify_code(rec->ip, ppc_inst(PPC_RAW_NOP()),
+			 ppc_inst(PPC_RAW_BRANCH((long)ftrace_get_ool_stub(rec) - (long)rec->ip)));
+
+	return ret;
+}
+
+int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr)
+{
+	/*
+	 * This should never be called since we override ftrace_replace_code(),
+	 * as well as ftrace_init_nop()
+	 */
+	WARN_ON(1);
+	return -EINVAL;
+}
+
+void ftrace_replace_code(int enable)
+{
+	ppc_inst_t old, new, call_inst, new_call_inst;
+	ppc_inst_t nop_inst = ppc_inst(PPC_RAW_NOP());
+	unsigned long ip, new_addr, addr;
+	struct ftrace_rec_iter *iter;
+	struct dyn_ftrace *rec;
+	int ret = 0, update;
+
+	for_ftrace_rec_iter(iter) {
+		rec = ftrace_rec_iter_record(iter);
+		ip = rec->ip;
+
+		if (rec->flags & FTRACE_FL_DISABLED && !(rec->flags & FTRACE_FL_ENABLED))
+			continue;
+
+		addr = ftrace_get_addr_curr(rec);
+		new_addr = ftrace_get_addr_new(rec);
+		update = ftrace_update_record(rec, enable);
+
+		if (IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE) && update != FTRACE_UPDATE_IGNORE) {
+			ip = ftrace_get_ool_stub(rec) + MCOUNT_INSN_SIZE;
+			ret = ftrace_get_call_inst(rec, (unsigned long)ftrace_caller, &nop_inst);
+			if (ret)
+				goto out;
+		}
+
+		switch (update) {
+		case FTRACE_UPDATE_IGNORE:
+		default:
+			continue;
+		case FTRACE_UPDATE_MODIFY_CALL:
+			ret = ftrace_get_call_inst(rec, new_addr, &new_call_inst);
+			ret |= ftrace_get_call_inst(rec, addr, &call_inst);
+			ret |= ftrace_rec_update_ops(rec);
+			old = call_inst;
+			new = new_call_inst;
+			break;
+		case FTRACE_UPDATE_MAKE_NOP:
+			ret = ftrace_get_call_inst(rec, addr, &call_inst);
+			ret |= ftrace_rec_set_nop_ops(rec);
+			old = call_inst;
+			new = nop_inst;
+			break;
+		case FTRACE_UPDATE_MAKE_CALL:
+			ret = ftrace_get_call_inst(rec, new_addr, &call_inst);
+			ret |= ftrace_rec_update_ops(rec);
+			old = nop_inst;
+			new = call_inst;
+			break;
+		}
+
+		if (!ret)
+			ret = ftrace_modify_code(ip, old, new);
+
+		if (!ret && IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE) &&
+		    (update == FTRACE_UPDATE_MAKE_NOP || update == FTRACE_UPDATE_MAKE_CALL)) {
+			/* Update the actual ftrace location */
+			call_inst = ppc_inst(PPC_RAW_BRANCH((long)ftrace_get_ool_stub(rec) -
+							    (long)rec->ip));
+			nop_inst = ppc_inst(PPC_RAW_NOP());
+			ip = rec->ip;
+
+			if (update == FTRACE_UPDATE_MAKE_NOP)
+				ret = ftrace_modify_code(ip, call_inst, nop_inst);
+			else
+				ret = ftrace_modify_code(ip, nop_inst, call_inst);
+
+			if (ret)
+				goto out;
+		}
+
+		if (ret)
+			goto out;
+	}
+
+out:
+	if (ret)
+		ftrace_bug(ret, rec);
+	return;
+}
+
+int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec)
+{
+	unsigned long addr, ip = rec->ip;
+	ppc_inst_t old, new;
+	int ret = 0;
+
+	/* Verify instructions surrounding the ftrace location */
+	if (IS_ENABLED(CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY)) {
+		/* Expect nops */
+		if (!IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE))
+			ret = ftrace_validate_inst(ip - 4, ppc_inst(PPC_RAW_NOP()));
+		if (!ret)
+			ret = ftrace_validate_inst(ip, ppc_inst(PPC_RAW_NOP()));
+	} else if (IS_ENABLED(CONFIG_PPC32)) {
+		/* Expected sequence: 'mflr r0', 'stw r0,4(r1)', 'bl _mcount' */
+		ret = ftrace_validate_inst(ip - 8, ppc_inst(PPC_RAW_MFLR(_R0)));
+		if (ret)
+			return ret;
+		ret = ftrace_modify_code(ip - 4, ppc_inst(PPC_RAW_STW(_R0, _R1, 4)),
+					 ppc_inst(PPC_RAW_NOP()));
+	} else if (IS_ENABLED(CONFIG_MPROFILE_KERNEL)) {
+		/* Expected sequence: 'mflr r0', ['std r0,16(r1)'], 'bl _mcount' */
+		ret = ftrace_read_inst(ip - 4, &old);
+		if (!ret && !ppc_inst_equal(old, ppc_inst(PPC_RAW_MFLR(_R0)))) {
+			/* Gcc v5.x emit the additional 'std' instruction, gcc v6.x don't */
+			ret = ftrace_validate_inst(ip - 8, ppc_inst(PPC_RAW_MFLR(_R0)));
+			if (ret)
+				return ret;
+			ret = ftrace_modify_code(ip - 4, ppc_inst(PPC_RAW_STD(_R0, _R1, 16)),
+						 ppc_inst(PPC_RAW_NOP()));
+		}
+	} else {
+		return -EINVAL;
+	}
+
+	if (ret)
+		return ret;
+
+	/* Set up out-of-line stub */
+	if (IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE)) {
+		ret = ftrace_init_ool_stub(mod, rec);
+		goto out;
+	}
+
+	/* Nop-out the ftrace location */
+	new = ppc_inst(PPC_RAW_NOP());
+	addr = MCOUNT_ADDR;
+	if (IS_ENABLED(CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY)) {
+		/* we instead patch-in the 'mflr r0' */
+		old = ppc_inst(PPC_RAW_NOP());
+		new = ppc_inst(PPC_RAW_MFLR(_R0));
+		ret = ftrace_modify_code(ip - 4, old, new);
+	} else if (is_offset_in_branch_range(addr - ip)) {
+		/* Within range */
+		old = ftrace_create_branch_inst(ip, addr, 1);
+		ret = ftrace_modify_code(ip, old, new);
+	} else if (core_kernel_text(ip) || (IS_ENABLED(CONFIG_MODULES) && mod)) {
+		/*
+		 * We would be branching to a linker-generated stub, or to the module _mcount
+		 * stub. Let's just confirm we have a 'bl' here.
+		 */
+		ret = ftrace_read_inst(ip, &old);
+		if (ret)
+			return ret;
+		if (!is_bl_op(old)) {
+			pr_err("0x%lx: expected (bl) != found (%08lx)\n", ip, ppc_inst_as_ulong(old));
+			return -EINVAL;
+		}
+		ret = patch_instruction((u32 *)ip, new);
+	} else {
+		return -EINVAL;
+	}
+
+out:
+	if (!ret)
+		ret = ftrace_rec_set_nop_ops(rec);
+
+	return ret;
+}
+
+int ftrace_update_ftrace_func(ftrace_func_t func)
+{
+	unsigned long ip = (unsigned long)(&ftrace_call);
+	ppc_inst_t old, new;
+	int ret;
+
+	/*
+	 * When using CALL_OPS, the function to call is associated with the
+	 * call site, and we don't have a global function pointer to update.
+	 */
+	if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS))
+		return 0;
+
+	old = ppc_inst_read((u32 *)&ftrace_call);
+	new = ftrace_create_branch_inst(ip, ppc_function_entry(func), 1);
+	ret = ftrace_modify_code(ip, old, new);
+
+	/* Also update the regs callback function */
+	if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) && !ret) {
+		ip = (unsigned long)(&ftrace_regs_call);
+		old = ppc_inst_read((u32 *)&ftrace_regs_call);
+		new = ftrace_create_branch_inst(ip, ppc_function_entry(func), 1);
+		ret = ftrace_modify_code(ip, old, new);
+	}
+
+	return ret;
+}
+
+/*
+ * Use the default ftrace_modify_all_code, but without
+ * stop_machine().
+ */
+void arch_ftrace_update_code(int command)
+{
+	ftrace_modify_all_code(command);
+}
+
+void ftrace_free_init_tramp(void)
+{
+	int i;
+
+	for (i = 0; i < NUM_FTRACE_TRAMPS && ftrace_tramps[i]; i++)
+		if (ftrace_tramps[i] == (unsigned long)ftrace_tramp_init) {
+			ftrace_tramps[i] = 0;
+			return;
+		}
+}
+
+static void __init add_ftrace_tramp(unsigned long tramp)
+{
+	int i;
+
+	for (i = 0; i < NUM_FTRACE_TRAMPS; i++)
+		if (!ftrace_tramps[i]) {
+			ftrace_tramps[i] = tramp;
+			return;
+		}
+}
+
+int __init ftrace_dyn_arch_init(void)
+{
+	unsigned int *tramp[] = { ftrace_tramp_text, ftrace_tramp_init };
+	unsigned long addr = FTRACE_REGS_ADDR;
+	long reladdr;
+	int i;
+	u32 stub_insns[] = {
+#ifdef CONFIG_PPC_KERNEL_PCREL
+		/* pla r12,addr */
+		PPC_PREFIX_MLS | __PPC_PRFX_R(1),
+		PPC_INST_PADDI | ___PPC_RT(_R12),
+		PPC_RAW_MTCTR(_R12),
+		PPC_RAW_BCTR()
+#elif defined(CONFIG_PPC64)
+		PPC_RAW_LD(_R12, _R13, offsetof(struct paca_struct, kernel_toc)),
+		PPC_RAW_ADDIS(_R12, _R12, 0),
+		PPC_RAW_ADDI(_R12, _R12, 0),
+		PPC_RAW_MTCTR(_R12),
+		PPC_RAW_BCTR()
+#else
+		PPC_RAW_LIS(_R12, 0),
+		PPC_RAW_ADDI(_R12, _R12, 0),
+		PPC_RAW_MTCTR(_R12),
+		PPC_RAW_BCTR()
+#endif
+	};
+
+	if (IS_ENABLED(CONFIG_PPC_KERNEL_PCREL)) {
+		for (i = 0; i < 2; i++) {
+			reladdr = addr - (unsigned long)tramp[i];
+
+			if (reladdr >= (long)SZ_8G || reladdr < -(long)SZ_8G) {
+				pr_err("Address of %ps out of range of pcrel address.\n",
+					(void *)addr);
+				return -1;
+			}
+
+			memcpy(tramp[i], stub_insns, sizeof(stub_insns));
+			tramp[i][0] |= IMM_H18(reladdr);
+			tramp[i][1] |= IMM_L(reladdr);
+			add_ftrace_tramp((unsigned long)tramp[i]);
+		}
+	} else if (IS_ENABLED(CONFIG_PPC64)) {
+		reladdr = addr - kernel_toc_addr();
+
+		if (reladdr >= (long)SZ_2G || reladdr < -(long long)SZ_2G) {
+			pr_err("Address of %ps out of range of kernel_toc.\n",
+				(void *)addr);
+			return -1;
+		}
+
+		for (i = 0; i < 2; i++) {
+			memcpy(tramp[i], stub_insns, sizeof(stub_insns));
+			tramp[i][1] |= PPC_HA(reladdr);
+			tramp[i][2] |= PPC_LO(reladdr);
+			add_ftrace_tramp((unsigned long)tramp[i]);
+		}
+	} else {
+		for (i = 0; i < 2; i++) {
+			memcpy(tramp[i], stub_insns, sizeof(stub_insns));
+			tramp[i][0] |= PPC_HA(addr);
+			tramp[i][1] |= PPC_LO(addr);
+			add_ftrace_tramp((unsigned long)tramp[i]);
+		}
+	}
+
+	return 0;
+}
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
+		       struct ftrace_ops *op, struct ftrace_regs *fregs)
+{
+	unsigned long sp = arch_ftrace_regs(fregs)->regs.gpr[1];
+
+	if (unlikely(ftrace_graph_is_dead()))
+		goto out;
+
+	if (unlikely(atomic_read(&current->tracing_graph_pause)))
+		goto out;
+
+	if (!function_graph_enter_regs(parent_ip, ip, 0, (unsigned long *)sp, fregs))
+		parent_ip = ppc_function_entry(return_to_handler);
+
+out:
+	arch_ftrace_regs(fregs)->regs.link = parent_ip;
+}
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */

linux-7.2.3/arch/powerpc/kernel/trace/ftrace_64_pg.c

@@ -0,0 +1,832 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Code for replacing ftrace calls with jumps.
+ *
+ * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
+ *
+ * Thanks goes out to P.A. Semi, Inc for supplying me with a PPC64 box.
+ *
+ * Added function graph tracer code, taken from x86 that was written
+ * by Frederic Weisbecker, and ported to PPC by Steven Rostedt.
+ *
+ */
+
+#define pr_fmt(fmt) "ftrace-powerpc: " fmt
+
+#include <linux/spinlock.h>
+#include <linux/hardirq.h>
+#include <linux/uaccess.h>
+#include <linux/module.h>
+#include <linux/ftrace.h>
+#include <linux/percpu.h>
+#include <linux/init.h>
+#include <linux/list.h>
+
+#include <asm/cacheflush.h>
+#include <asm/text-patching.h>
+#include <asm/ftrace.h>
+#include <asm/syscall.h>
+#include <asm/inst.h>
+
+/*
+ * We generally only have a single long_branch tramp and at most 2 or 3 plt
+ * tramps generated. But, we don't use the plt tramps currently. We also allot
+ * 2 tramps after .text and .init.text. So, we only end up with around 3 usable
+ * tramps in total. Set aside 8 just to be sure.
+ */
+#define	NUM_FTRACE_TRAMPS	8
+static unsigned long ftrace_tramps[NUM_FTRACE_TRAMPS];
+
+unsigned long ftrace_call_adjust(unsigned long addr)
+{
+	return addr;
+}
+
+static ppc_inst_t
+ftrace_call_replace(unsigned long ip, unsigned long addr, int link)
+{
+	ppc_inst_t op;
+
+	addr = ppc_function_entry((void *)addr);
+
+	/* if (link) set op to 'bl' else 'b' */
+	create_branch(&op, (u32 *)ip, addr, link ? BRANCH_SET_LINK : 0);
+
+	return op;
+}
+
+static inline int
+ftrace_modify_code(unsigned long ip, ppc_inst_t old, ppc_inst_t new)
+{
+	ppc_inst_t replaced;
+
+	/*
+	 * Note:
+	 * We are paranoid about modifying text, as if a bug was to happen, it
+	 * could cause us to read or write to someplace that could cause harm.
+	 * Carefully read and modify the code with probe_kernel_*(), and make
+	 * sure what we read is what we expected it to be before modifying it.
+	 */
+
+	/* read the text we want to modify */
+	if (copy_inst_from_kernel_nofault(&replaced, (void *)ip))
+		return -EFAULT;
+
+	/* Make sure it is what we expect it to be */
+	if (!ppc_inst_equal(replaced, old)) {
+		pr_err("%p: replaced (%08lx) != old (%08lx)", (void *)ip,
+		       ppc_inst_as_ulong(replaced), ppc_inst_as_ulong(old));
+		return -EINVAL;
+	}
+
+	/* replace the text with the new text */
+	return patch_instruction((u32 *)ip, new);
+}
+
+/*
+ * Helper functions that are the same for both PPC64 and PPC32.
+ */
+static int test_24bit_addr(unsigned long ip, unsigned long addr)
+{
+	addr = ppc_function_entry((void *)addr);
+
+	return is_offset_in_branch_range(addr - ip);
+}
+
+static int is_bl_op(ppc_inst_t op)
+{
+	return (ppc_inst_val(op) & ~PPC_LI_MASK) == PPC_RAW_BL(0);
+}
+
+static int is_b_op(ppc_inst_t op)
+{
+	return (ppc_inst_val(op) & ~PPC_LI_MASK) == PPC_RAW_BRANCH(0);
+}
+
+static unsigned long find_bl_target(unsigned long ip, ppc_inst_t op)
+{
+	int offset;
+
+	offset = PPC_LI(ppc_inst_val(op));
+	/* make it signed */
+	if (offset & 0x02000000)
+		offset |= 0xfe000000;
+
+	return ip + (long)offset;
+}
+
+#ifdef CONFIG_MODULES
+static struct module *ftrace_lookup_module(struct dyn_ftrace *rec)
+{
+	struct module *mod;
+
+	scoped_guard(rcu)
+		mod = __module_text_address(rec->ip);
+	if (!mod)
+		pr_err("No module loaded at addr=%lx\n", rec->ip);
+
+	return mod;
+}
+
+static int
+__ftrace_make_nop(struct module *mod,
+		  struct dyn_ftrace *rec, unsigned long addr)
+{
+	unsigned long entry, ptr, tramp;
+	unsigned long ip = rec->ip;
+	ppc_inst_t op, pop;
+
+	if (!mod) {
+		mod = ftrace_lookup_module(rec);
+		if (!mod)
+			return -EINVAL;
+	}
+
+	/* read where this goes */
+	if (copy_inst_from_kernel_nofault(&op, (void *)ip)) {
+		pr_err("Fetching opcode failed.\n");
+		return -EFAULT;
+	}
+
+	/* Make sure that this is still a 24bit jump */
+	if (!is_bl_op(op)) {
+		pr_err("Not expected bl: opcode is %08lx\n", ppc_inst_as_ulong(op));
+		return -EINVAL;
+	}
+
+	/* lets find where the pointer goes */
+	tramp = find_bl_target(ip, op);
+
+	pr_devel("ip:%lx jumps to %lx", ip, tramp);
+
+	if (module_trampoline_target(mod, tramp, &ptr)) {
+		pr_err("Failed to get trampoline target\n");
+		return -EFAULT;
+	}
+
+	pr_devel("trampoline target %lx", ptr);
+
+	entry = ppc_global_function_entry((void *)addr);
+	/* This should match what was called */
+	if (ptr != entry) {
+		pr_err("addr %lx does not match expected %lx\n", ptr, entry);
+		return -EINVAL;
+	}
+
+	if (IS_ENABLED(CONFIG_MPROFILE_KERNEL)) {
+		if (copy_inst_from_kernel_nofault(&op, (void *)(ip - 4))) {
+			pr_err("Fetching instruction at %lx failed.\n", ip - 4);
+			return -EFAULT;
+		}
+
+		/* We expect either a mflr r0, or a std r0, LRSAVE(r1) */
+		if (!ppc_inst_equal(op, ppc_inst(PPC_RAW_MFLR(_R0))) &&
+		    !ppc_inst_equal(op, ppc_inst(PPC_INST_STD_LR))) {
+			pr_err("Unexpected instruction %08lx around bl _mcount\n",
+			       ppc_inst_as_ulong(op));
+			return -EINVAL;
+		}
+	} else if (IS_ENABLED(CONFIG_PPC64)) {
+		/*
+		 * Check what is in the next instruction. We can see ld r2,40(r1), but
+		 * on first pass after boot we will see mflr r0.
+		 */
+		if (copy_inst_from_kernel_nofault(&op, (void *)(ip + 4))) {
+			pr_err("Fetching op failed.\n");
+			return -EFAULT;
+		}
+
+		if (!ppc_inst_equal(op,  ppc_inst(PPC_INST_LD_TOC))) {
+			pr_err("Expected %08lx found %08lx\n", PPC_INST_LD_TOC,
+			       ppc_inst_as_ulong(op));
+			return -EINVAL;
+		}
+	}
+
+	/*
+	 * When using -mprofile-kernel or PPC32 there is no load to jump over.
+	 *
+	 * Otherwise our original call site looks like:
+	 *
+	 * bl <tramp>
+	 * ld r2,XX(r1)
+	 *
+	 * Milton Miller pointed out that we can not simply nop the branch.
+	 * If a task was preempted when calling a trace function, the nops
+	 * will remove the way to restore the TOC in r2 and the r2 TOC will
+	 * get corrupted.
+	 *
+	 * Use a b +8 to jump over the load.
+	 */
+	if (IS_ENABLED(CONFIG_MPROFILE_KERNEL) || IS_ENABLED(CONFIG_PPC32))
+		pop = ppc_inst(PPC_RAW_NOP());
+	else
+		pop = ppc_inst(PPC_RAW_BRANCH(8));	/* b +8 */
+
+	if (patch_instruction((u32 *)ip, pop)) {
+		pr_err("Patching NOP failed.\n");
+		return -EPERM;
+	}
+
+	return 0;
+}
+#else
+static int __ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr)
+{
+	return 0;
+}
+#endif /* CONFIG_MODULES */
+
+static unsigned long find_ftrace_tramp(unsigned long ip)
+{
+	int i;
+
+	/*
+	 * We have the compiler generated long_branch tramps at the end
+	 * and we prefer those
+	 */
+	for (i = NUM_FTRACE_TRAMPS - 1; i >= 0; i--)
+		if (!ftrace_tramps[i])
+			continue;
+		else if (is_offset_in_branch_range(ftrace_tramps[i] - ip))
+			return ftrace_tramps[i];
+
+	return 0;
+}
+
+static int add_ftrace_tramp(unsigned long tramp)
+{
+	int i;
+
+	for (i = 0; i < NUM_FTRACE_TRAMPS; i++)
+		if (!ftrace_tramps[i]) {
+			ftrace_tramps[i] = tramp;
+			return 0;
+		}
+
+	return -1;
+}
+
+/*
+ * If this is a compiler generated long_branch trampoline (essentially, a
+ * trampoline that has a branch to _mcount()), we re-write the branch to
+ * instead go to ftrace_[regs_]caller() and note down the location of this
+ * trampoline.
+ */
+static int setup_mcount_compiler_tramp(unsigned long tramp)
+{
+	int i;
+	ppc_inst_t op;
+	unsigned long ptr;
+
+	/* Is this a known long jump tramp? */
+	for (i = 0; i < NUM_FTRACE_TRAMPS; i++)
+		if (ftrace_tramps[i] == tramp)
+			return 0;
+
+	/* New trampoline -- read where this goes */
+	if (copy_inst_from_kernel_nofault(&op, (void *)tramp)) {
+		pr_debug("Fetching opcode failed.\n");
+		return -1;
+	}
+
+	/* Is this a 24 bit branch? */
+	if (!is_b_op(op)) {
+		pr_debug("Trampoline is not a long branch tramp.\n");
+		return -1;
+	}
+
+	/* lets find where the pointer goes */
+	ptr = find_bl_target(tramp, op);
+
+	if (ptr != ppc_global_function_entry((void *)_mcount)) {
+		pr_debug("Trampoline target %p is not _mcount\n", (void *)ptr);
+		return -1;
+	}
+
+	/* Let's re-write the tramp to go to ftrace_[regs_]caller */
+	if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS))
+		ptr = ppc_global_function_entry((void *)ftrace_regs_caller);
+	else
+		ptr = ppc_global_function_entry((void *)ftrace_caller);
+
+	if (patch_branch((u32 *)tramp, ptr, 0)) {
+		pr_debug("REL24 out of range!\n");
+		return -1;
+	}
+
+	if (add_ftrace_tramp(tramp)) {
+		pr_debug("No tramp locations left\n");
+		return -1;
+	}
+
+	return 0;
+}
+
+static int __ftrace_make_nop_kernel(struct dyn_ftrace *rec, unsigned long addr)
+{
+	unsigned long tramp, ip = rec->ip;
+	ppc_inst_t op;
+
+	/* Read where this goes */
+	if (copy_inst_from_kernel_nofault(&op, (void *)ip)) {
+		pr_err("Fetching opcode failed.\n");
+		return -EFAULT;
+	}
+
+	/* Make sure that this is still a 24bit jump */
+	if (!is_bl_op(op)) {
+		pr_err("Not expected bl: opcode is %08lx\n", ppc_inst_as_ulong(op));
+		return -EINVAL;
+	}
+
+	/* Let's find where the pointer goes */
+	tramp = find_bl_target(ip, op);
+
+	pr_devel("ip:%lx jumps to %lx", ip, tramp);
+
+	if (setup_mcount_compiler_tramp(tramp)) {
+		/* Are other trampolines reachable? */
+		if (!find_ftrace_tramp(ip)) {
+			pr_err("No ftrace trampolines reachable from %ps\n",
+					(void *)ip);
+			return -EINVAL;
+		}
+	}
+
+	if (patch_instruction((u32 *)ip, ppc_inst(PPC_RAW_NOP()))) {
+		pr_err("Patching NOP failed.\n");
+		return -EPERM;
+	}
+
+	return 0;
+}
+
+int ftrace_make_nop(struct module *mod,
+		    struct dyn_ftrace *rec, unsigned long addr)
+{
+	unsigned long ip = rec->ip;
+	ppc_inst_t old, new;
+
+	/*
+	 * If the calling address is more that 24 bits away,
+	 * then we had to use a trampoline to make the call.
+	 * Otherwise just update the call site.
+	 */
+	if (test_24bit_addr(ip, addr)) {
+		/* within range */
+		old = ftrace_call_replace(ip, addr, 1);
+		new = ppc_inst(PPC_RAW_NOP());
+		return ftrace_modify_code(ip, old, new);
+	} else if (core_kernel_text(ip)) {
+		return __ftrace_make_nop_kernel(rec, addr);
+	} else if (!IS_ENABLED(CONFIG_MODULES)) {
+		return -EINVAL;
+	}
+
+	return __ftrace_make_nop(mod, rec, addr);
+}
+
+#ifdef CONFIG_MODULES
+/*
+ * Examine the existing instructions for __ftrace_make_call.
+ * They should effectively be a NOP, and follow formal constraints,
+ * depending on the ABI. Return false if they don't.
+ */
+static bool expected_nop_sequence(void *ip, ppc_inst_t op0, ppc_inst_t op1)
+{
+	if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS))
+		return ppc_inst_equal(op0, ppc_inst(PPC_RAW_NOP()));
+	else
+		return ppc_inst_equal(op0, ppc_inst(PPC_RAW_BRANCH(8))) &&
+		       ppc_inst_equal(op1, ppc_inst(PPC_INST_LD_TOC));
+}
+
+static int
+__ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
+{
+	ppc_inst_t op[2];
+	void *ip = (void *)rec->ip;
+	unsigned long entry, ptr, tramp;
+	struct module *mod = ftrace_lookup_module(rec);
+
+	if (!mod)
+		return -EINVAL;
+
+	/* read where this goes */
+	if (copy_inst_from_kernel_nofault(op, ip))
+		return -EFAULT;
+
+	if (!IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) &&
+	    copy_inst_from_kernel_nofault(op + 1, ip + 4))
+		return -EFAULT;
+
+	if (!expected_nop_sequence(ip, op[0], op[1])) {
+		pr_err("Unexpected call sequence at %p: %08lx %08lx\n", ip,
+		       ppc_inst_as_ulong(op[0]), ppc_inst_as_ulong(op[1]));
+		return -EINVAL;
+	}
+
+	/* If we never set up ftrace trampoline(s), then bail */
+	if (!mod->arch.tramp ||
+	    (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) && !mod->arch.tramp_regs)) {
+		pr_err("No ftrace trampoline\n");
+		return -EINVAL;
+	}
+
+	if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) && rec->flags & FTRACE_FL_REGS)
+		tramp = mod->arch.tramp_regs;
+	else
+		tramp = mod->arch.tramp;
+
+	if (module_trampoline_target(mod, tramp, &ptr)) {
+		pr_err("Failed to get trampoline target\n");
+		return -EFAULT;
+	}
+
+	pr_devel("trampoline target %lx", ptr);
+
+	entry = ppc_global_function_entry((void *)addr);
+	/* This should match what was called */
+	if (ptr != entry) {
+		pr_err("addr %lx does not match expected %lx\n", ptr, entry);
+		return -EINVAL;
+	}
+
+	if (patch_branch(ip, tramp, BRANCH_SET_LINK)) {
+		pr_err("REL24 out of range!\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+#else
+static int __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
+{
+	return 0;
+}
+#endif /* CONFIG_MODULES */
+
+static int __ftrace_make_call_kernel(struct dyn_ftrace *rec, unsigned long addr)
+{
+	ppc_inst_t op;
+	void *ip = (void *)rec->ip;
+	unsigned long tramp, entry, ptr;
+
+	/* Make sure we're being asked to patch branch to a known ftrace addr */
+	entry = ppc_global_function_entry((void *)ftrace_caller);
+	ptr = ppc_global_function_entry((void *)addr);
+
+	if (ptr != entry && IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS))
+		entry = ppc_global_function_entry((void *)ftrace_regs_caller);
+
+	if (ptr != entry) {
+		pr_err("Unknown ftrace addr to patch: %ps\n", (void *)ptr);
+		return -EINVAL;
+	}
+
+	/* Make sure we have a nop */
+	if (copy_inst_from_kernel_nofault(&op, ip)) {
+		pr_err("Unable to read ftrace location %p\n", ip);
+		return -EFAULT;
+	}
+
+	if (!ppc_inst_equal(op, ppc_inst(PPC_RAW_NOP()))) {
+		pr_err("Unexpected call sequence at %p: %08lx\n",
+		       ip, ppc_inst_as_ulong(op));
+		return -EINVAL;
+	}
+
+	tramp = find_ftrace_tramp((unsigned long)ip);
+	if (!tramp) {
+		pr_err("No ftrace trampolines reachable from %ps\n", ip);
+		return -EINVAL;
+	}
+
+	if (patch_branch(ip, tramp, BRANCH_SET_LINK)) {
+		pr_err("Error patching branch to ftrace tramp!\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
+{
+	unsigned long ip = rec->ip;
+	ppc_inst_t old, new;
+
+	/*
+	 * If the calling address is more that 24 bits away,
+	 * then we had to use a trampoline to make the call.
+	 * Otherwise just update the call site.
+	 */
+	if (test_24bit_addr(ip, addr)) {
+		/* within range */
+		old = ppc_inst(PPC_RAW_NOP());
+		new = ftrace_call_replace(ip, addr, 1);
+		return ftrace_modify_code(ip, old, new);
+	} else if (core_kernel_text(ip)) {
+		return __ftrace_make_call_kernel(rec, addr);
+	} else if (!IS_ENABLED(CONFIG_MODULES)) {
+		/* We should not get here without modules */
+		return -EINVAL;
+	}
+
+	return __ftrace_make_call(rec, addr);
+}
+
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
+#ifdef CONFIG_MODULES
+static int
+__ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
+					unsigned long addr)
+{
+	ppc_inst_t op;
+	unsigned long ip = rec->ip;
+	unsigned long entry, ptr, tramp;
+	struct module *mod = ftrace_lookup_module(rec);
+
+	if (!mod)
+		return -EINVAL;
+
+	/* If we never set up ftrace trampolines, then bail */
+	if (!mod->arch.tramp || !mod->arch.tramp_regs) {
+		pr_err("No ftrace trampoline\n");
+		return -EINVAL;
+	}
+
+	/* read where this goes */
+	if (copy_inst_from_kernel_nofault(&op, (void *)ip)) {
+		pr_err("Fetching opcode failed.\n");
+		return -EFAULT;
+	}
+
+	/* Make sure that this is still a 24bit jump */
+	if (!is_bl_op(op)) {
+		pr_err("Not expected bl: opcode is %08lx\n", ppc_inst_as_ulong(op));
+		return -EINVAL;
+	}
+
+	/* lets find where the pointer goes */
+	tramp = find_bl_target(ip, op);
+	entry = ppc_global_function_entry((void *)old_addr);
+
+	pr_devel("ip:%lx jumps to %lx", ip, tramp);
+
+	if (tramp != entry) {
+		/* old_addr is not within range, so we must have used a trampoline */
+		if (module_trampoline_target(mod, tramp, &ptr)) {
+			pr_err("Failed to get trampoline target\n");
+			return -EFAULT;
+		}
+
+		pr_devel("trampoline target %lx", ptr);
+
+		/* This should match what was called */
+		if (ptr != entry) {
+			pr_err("addr %lx does not match expected %lx\n", ptr, entry);
+			return -EINVAL;
+		}
+	}
+
+	/* The new target may be within range */
+	if (test_24bit_addr(ip, addr)) {
+		/* within range */
+		if (patch_branch((u32 *)ip, addr, BRANCH_SET_LINK)) {
+			pr_err("REL24 out of range!\n");
+			return -EINVAL;
+		}
+
+		return 0;
+	}
+
+	if (rec->flags & FTRACE_FL_REGS)
+		tramp = mod->arch.tramp_regs;
+	else
+		tramp = mod->arch.tramp;
+
+	if (module_trampoline_target(mod, tramp, &ptr)) {
+		pr_err("Failed to get trampoline target\n");
+		return -EFAULT;
+	}
+
+	pr_devel("trampoline target %lx", ptr);
+
+	entry = ppc_global_function_entry((void *)addr);
+	/* This should match what was called */
+	if (ptr != entry) {
+		pr_err("addr %lx does not match expected %lx\n", ptr, entry);
+		return -EINVAL;
+	}
+
+	if (patch_branch((u32 *)ip, tramp, BRANCH_SET_LINK)) {
+		pr_err("REL24 out of range!\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+#else
+static int __ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, unsigned long addr)
+{
+	return 0;
+}
+#endif
+
+int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
+			unsigned long addr)
+{
+	unsigned long ip = rec->ip;
+	ppc_inst_t old, new;
+
+	/*
+	 * If the calling address is more that 24 bits away,
+	 * then we had to use a trampoline to make the call.
+	 * Otherwise just update the call site.
+	 */
+	if (test_24bit_addr(ip, addr) && test_24bit_addr(ip, old_addr)) {
+		/* within range */
+		old = ftrace_call_replace(ip, old_addr, 1);
+		new = ftrace_call_replace(ip, addr, 1);
+		return ftrace_modify_code(ip, old, new);
+	} else if (core_kernel_text(ip)) {
+		/*
+		 * We always patch out of range locations to go to the regs
+		 * variant, so there is nothing to do here
+		 */
+		return 0;
+	} else if (!IS_ENABLED(CONFIG_MODULES)) {
+		/* We should not get here without modules */
+		return -EINVAL;
+	}
+
+	return __ftrace_modify_call(rec, old_addr, addr);
+}
+#endif
+
+int ftrace_update_ftrace_func(ftrace_func_t func)
+{
+	unsigned long ip = (unsigned long)(&ftrace_call);
+	ppc_inst_t old, new;
+	int ret;
+
+	old = ppc_inst_read((u32 *)&ftrace_call);
+	new = ftrace_call_replace(ip, (unsigned long)func, 1);
+	ret = ftrace_modify_code(ip, old, new);
+
+	/* Also update the regs callback function */
+	if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) && !ret) {
+		ip = (unsigned long)(&ftrace_regs_call);
+		old = ppc_inst_read((u32 *)&ftrace_regs_call);
+		new = ftrace_call_replace(ip, (unsigned long)func, 1);
+		ret = ftrace_modify_code(ip, old, new);
+	}
+
+	return ret;
+}
+
+/*
+ * Use the default ftrace_modify_all_code, but without
+ * stop_machine().
+ */
+void arch_ftrace_update_code(int command)
+{
+	ftrace_modify_all_code(command);
+}
+
+#ifdef CONFIG_PPC64
+#define PACATOC offsetof(struct paca_struct, kernel_toc)
+
+extern unsigned int ftrace_tramp_text[], ftrace_tramp_init[];
+
+void ftrace_free_init_tramp(void)
+{
+	int i;
+
+	for (i = 0; i < NUM_FTRACE_TRAMPS && ftrace_tramps[i]; i++)
+		if (ftrace_tramps[i] == (unsigned long)ftrace_tramp_init) {
+			ftrace_tramps[i] = 0;
+			return;
+		}
+}
+
+int __init ftrace_dyn_arch_init(void)
+{
+	int i;
+	unsigned int *tramp[] = { ftrace_tramp_text, ftrace_tramp_init };
+	u32 stub_insns[] = {
+		PPC_RAW_LD(_R12, _R13, PACATOC),
+		PPC_RAW_ADDIS(_R12, _R12, 0),
+		PPC_RAW_ADDI(_R12, _R12, 0),
+		PPC_RAW_MTCTR(_R12),
+		PPC_RAW_BCTR()
+	};
+	unsigned long addr;
+	long reladdr;
+
+	if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS))
+		addr = ppc_global_function_entry((void *)ftrace_regs_caller);
+	else
+		addr = ppc_global_function_entry((void *)ftrace_caller);
+
+	reladdr = addr - kernel_toc_addr();
+
+	if (reladdr >= SZ_2G || reladdr < -(long)SZ_2G) {
+		pr_err("Address of %ps out of range of kernel_toc.\n",
+				(void *)addr);
+		return -1;
+	}
+
+	for (i = 0; i < 2; i++) {
+		memcpy(tramp[i], stub_insns, sizeof(stub_insns));
+		tramp[i][1] |= PPC_HA(reladdr);
+		tramp[i][2] |= PPC_LO(reladdr);
+		add_ftrace_tramp((unsigned long)tramp[i]);
+	}
+
+	return 0;
+}
+#endif
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+
+extern void ftrace_graph_call(void);
+extern void ftrace_graph_stub(void);
+
+static int ftrace_modify_ftrace_graph_caller(bool enable)
+{
+	unsigned long ip = (unsigned long)(&ftrace_graph_call);
+	unsigned long addr = (unsigned long)(&ftrace_graph_caller);
+	unsigned long stub = (unsigned long)(&ftrace_graph_stub);
+	ppc_inst_t old, new;
+
+	if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_ARGS))
+		return 0;
+
+	old = ftrace_call_replace(ip, enable ? stub : addr, 0);
+	new = ftrace_call_replace(ip, enable ? addr : stub, 0);
+
+	return ftrace_modify_code(ip, old, new);
+}
+
+int ftrace_enable_ftrace_graph_caller(void)
+{
+	return ftrace_modify_ftrace_graph_caller(true);
+}
+
+int ftrace_disable_ftrace_graph_caller(void)
+{
+	return ftrace_modify_ftrace_graph_caller(false);
+}
+
+/*
+ * Hook the return address and push it in the stack of return addrs
+ * in current thread info. Return the address we want to divert to.
+ */
+static unsigned long
+__prepare_ftrace_return(unsigned long parent, unsigned long ip, unsigned long sp,
+			struct ftrace_regs *fregs)
+{
+	unsigned long return_hooker;
+
+	if (unlikely(ftrace_graph_is_dead()))
+		goto out;
+
+	if (unlikely(atomic_read(&current->tracing_graph_pause)))
+		goto out;
+
+	return_hooker = ppc_function_entry(return_to_handler);
+
+	if (!function_graph_enter_regs(parent, ip, 0, (unsigned long *)sp, fregs))
+		parent = return_hooker;
+
+out:
+	return parent;
+}
+
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_ARGS
+void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
+		       struct ftrace_ops *op, struct ftrace_regs *fregs)
+{
+	arch_ftrace_regs(fregs)->regs.link = __prepare_ftrace_return(parent_ip, ip,
+						arch_ftrace_regs(fregs)->regs.gpr[1], fregs);
+}
+#else
+unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip,
+				    unsigned long sp)
+{
+	return __prepare_ftrace_return(parent, ip, sp, NULL);
+}
+#endif
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
+
+#ifdef CONFIG_PPC64_ELF_ABI_V1
+char *arch_ftrace_match_adjust(char *str, const char *search)
+{
+	if (str[0] == '.' && search[0] != '.')
+		return str + 1;
+	else
+		return str;
+}
+#endif /* CONFIG_PPC64_ELF_ABI_V1 */

linux-7.2.3/arch/powerpc/kernel/trace/ftrace_64_pg_entry.S

@@ -0,0 +1,132 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Split from ftrace_64.S
+ */
+
+#include <linux/export.h>
+#include <linux/magic.h>
+#include <asm/ppc_asm.h>
+#include <asm/asm-offsets.h>
+#include <asm/ftrace.h>
+#include <asm/ppc-opcode.h>
+
+_GLOBAL_TOC(ftrace_caller)
+	lbz	r3, PACA_FTRACE_ENABLED(r13)
+	cmpdi	r3, 0
+	beqlr
+
+	/* Taken from output of objdump from lib64/glibc */
+	mflr	r3
+	ld	r11, 0(r1)
+	stdu	r1, -112(r1)
+	std	r3, 128(r1)
+	ld	r4, 16(r11)
+	subi	r3, r3, MCOUNT_INSN_SIZE
+.globl ftrace_call
+ftrace_call:
+	bl	ftrace_stub
+	nop
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+.globl ftrace_graph_call
+ftrace_graph_call:
+	b	ftrace_graph_stub
+_GLOBAL(ftrace_graph_stub)
+#endif
+	ld	r0, 128(r1)
+	mtlr	r0
+	addi	r1, r1, 112
+
+_GLOBAL(ftrace_stub)
+	blr
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+_GLOBAL(ftrace_graph_caller)
+	addi	r5, r1, 112
+	/* load r4 with local address */
+	ld	r4, 128(r1)
+	subi	r4, r4, MCOUNT_INSN_SIZE
+
+	/* Grab the LR out of the caller stack frame */
+	ld	r11, 112(r1)
+	ld	r3, 16(r11)
+
+	bl	prepare_ftrace_return
+	nop
+
+	/*
+	 * prepare_ftrace_return gives us the address we divert to.
+	 * Change the LR in the callers stack frame to this.
+	 */
+	ld	r11, 112(r1)
+	std	r3, 16(r11)
+
+	ld	r0, 128(r1)
+	mtlr	r0
+	addi	r1, r1, 112
+	blr
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
+
+.pushsection ".tramp.ftrace.text","aw",@progbits;
+.globl ftrace_tramp_text
+ftrace_tramp_text:
+	.space 32
+.popsection
+
+.pushsection ".tramp.ftrace.init","aw",@progbits;
+.globl ftrace_tramp_init
+ftrace_tramp_init:
+	.space 32
+.popsection
+
+_GLOBAL(mcount)
+_GLOBAL(_mcount)
+EXPORT_SYMBOL(_mcount)
+	mflr	r12
+	mtctr	r12
+	mtlr	r0
+	bctr
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+_GLOBAL(return_to_handler)
+	/* need to save return values */
+#ifdef CONFIG_PPC64
+	std	r4,  -32(r1)
+	std	r3,  -24(r1)
+	/* save TOC */
+	std	r2,  -16(r1)
+	std	r31, -8(r1)
+	mr	r31, r1
+	stdu	r1, -112(r1)
+
+	/*
+	 * We might be called from a module.
+	 * Switch to our TOC to run inside the core kernel.
+	 */
+	LOAD_PACA_TOC()
+#else
+	stwu	r1, -16(r1)
+	stw	r3, 8(r1)
+	stw	r4, 12(r1)
+#endif
+
+	bl	ftrace_return_to_handler
+	nop
+
+	/* return value has real return address */
+	mtlr	r3
+
+#ifdef CONFIG_PPC64
+	ld	r1, 0(r1)
+	ld	r4,  -32(r1)
+	ld	r3,  -24(r1)
+	ld	r2,  -16(r1)
+	ld	r31, -8(r1)
+#else
+	lwz	r3, 8(r1)
+	lwz	r4, 12(r1)
+	addi	r1, r1, 16
+#endif
+
+	/* Jump back to real return address */
+	blr
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */

linux-7.2.3/arch/powerpc/kernel/trace/ftrace_entry.S

@@ -0,0 +1,479 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Split from ftrace_64.S
+ */
+
+#include <linux/export.h>
+#include <linux/magic.h>
+#include <asm/ppc_asm.h>
+#include <asm/asm-offsets.h>
+#include <asm/ftrace.h>
+#include <asm/ppc-opcode.h>
+#include <asm/thread_info.h>
+#include <asm/bug.h>
+#include <asm/ptrace.h>
+
+/*
+ *
+ * ftrace_caller()/ftrace_regs_caller() is the function that replaces _mcount()
+ * when ftrace is active.
+ *
+ * We arrive here after a function A calls function B, and we are the trace
+ * function for B. When we enter r1 points to A's stack frame, B has not yet
+ * had a chance to allocate one yet.
+ *
+ * Additionally r2 may point either to the TOC for A, or B, depending on
+ * whether B did a TOC setup sequence before calling us.
+ *
+ * On entry the LR points back to the _mcount() call site, and r0 holds the
+ * saved LR as it was on entry to B, ie. the original return address at the
+ * call site in A.
+ *
+ * Our job is to save the register state into a struct pt_regs (on the stack)
+ * and then arrange for the ftrace function to be called.
+ */
+.macro	ftrace_regs_entry allregs
+	/* Create a minimal stack frame for representing B */
+	PPC_STLU	r1, -STACK_FRAME_MIN_SIZE(r1)
+
+	/* Create our stack frame + pt_regs */
+	PPC_STLU	r1,-SWITCH_FRAME_SIZE(r1)
+
+	.if \allregs == 1
+	SAVE_GPRS(11, 12, r1)
+	.endif
+
+	/* Get the _mcount() call site out of LR */
+	mflr	r11
+
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
+	/* Load the ftrace_op */
+	PPC_LL	r12, -(MCOUNT_INSN_SIZE*2 + SZL)(r11)
+
+	/* Load direct_call from the ftrace_op */
+	PPC_LL	r12, FTRACE_OPS_DIRECT_CALL(r12)
+	PPC_LCMPI r12, 0
+	.if \allregs == 1
+	bne	.Lftrace_direct_call_regs
+	.else
+	bne	.Lftrace_direct_call
+	.endif
+#endif
+
+	/* Save the previous LR in pt_regs->link */
+	PPC_STL	r0, _LINK(r1)
+	/* Also save it in A's stack frame */
+	PPC_STL	r0, SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE+LRSAVE(r1)
+
+	/* Save all gprs to pt_regs */
+	SAVE_GPR(0, r1)
+	SAVE_GPRS(3, 10, r1)
+
+#ifdef CONFIG_PPC64
+	/* Ok to continue? */
+	lbz	r3, PACA_FTRACE_ENABLED(r13)
+	cmpdi	r3, 0
+	beq	ftrace_no_trace
+#endif
+
+	.if \allregs == 1
+	SAVE_GPR(2, r1)
+	SAVE_GPRS(13, 31, r1)
+	.else
+#if defined(CONFIG_LIVEPATCH_64) || defined(CONFIG_PPC_FTRACE_OUT_OF_LINE)
+	SAVE_GPR(14, r1)
+#endif
+	.endif
+
+	/* Save previous stack pointer (r1) */
+	addi	r8, r1, SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE
+	PPC_STL	r8, GPR1(r1)
+
+	.if \allregs == 1
+	/* Load special regs for save below */
+	mfcr	r7
+	mfmsr   r8
+	mfctr   r9
+	mfxer   r10
+	.else
+	/* Clear MSR to flag as ftrace_caller versus frace_regs_caller */
+	li	r8, 0
+	.endif
+
+#ifdef CONFIG_PPC64
+	/* Save callee's TOC in the ABI compliant location */
+	std	r2, STK_GOT(r1)
+	LOAD_PACA_TOC()		/* get kernel TOC in r2 */
+#endif
+
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS
+	/* r11 points to the instruction following the call to ftrace */
+	PPC_LL	r5, -(MCOUNT_INSN_SIZE*2 + SZL)(r11)
+	PPC_LL	r12, FTRACE_OPS_FUNC(r5)
+	mtctr	r12
+#else /* !CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS */
+#ifdef CONFIG_PPC64
+	LOAD_REG_ADDR(r3, function_trace_op)
+	ld	r5,0(r3)
+#else
+	lis	r3,function_trace_op@ha
+	lwz	r5,function_trace_op@l(r3)
+#endif
+#endif
+
+	/* Save special regs */
+	PPC_STL	r8, _MSR(r1)
+	.if \allregs == 1
+	PPC_STL	r7, _CCR(r1)
+	PPC_STL	r9, _CTR(r1)
+	PPC_STL	r10, _XER(r1)
+	.endif
+
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
+	/* Clear orig_gpr3 to later detect ftrace_direct call */
+	li	r7, 0
+	PPC_STL	r7, ORIG_GPR3(r1)
+#endif
+
+#ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE
+	/* Save our real return address in nvr for return */
+	.if \allregs == 0
+	SAVE_GPR(15, r1)
+	.endif
+	mr	r15, r11
+	/*
+	 * We want the ftrace location in the function, but our lr (in r11)
+	 * points at the 'mtlr r0' instruction in the out of line stub.  To
+	 * recover the ftrace location, we read the branch instruction in the
+	 * stub, and adjust our lr by the branch offset.
+	 *
+	 * See ftrace_init_ool_stub() for the profile sequence.
+	 */
+	lwz	r8, MCOUNT_INSN_SIZE(r11)
+	slwi	r8, r8, 6
+	srawi	r8, r8, 6
+	add	r3, r11, r8
+	/*
+	 * Override our nip to point past the branch in the original function.
+	 * This allows reliable stack trace and the ftrace stack tracer to work as-is.
+	 */
+	addi	r11, r3, MCOUNT_INSN_SIZE
+#else
+	/* Calculate ip from nip-4 into r3 for call below */
+	subi    r3, r11, MCOUNT_INSN_SIZE
+#endif
+
+	/* Save NIP as pt_regs->nip */
+	PPC_STL	r11, _NIP(r1)
+	/* Also save it in B's stackframe header for proper unwind */
+	PPC_STL	r11, LRSAVE+SWITCH_FRAME_SIZE(r1)
+#if defined(CONFIG_LIVEPATCH_64) || defined(CONFIG_PPC_FTRACE_OUT_OF_LINE)
+	mr	r14, r11	/* remember old NIP */
+#endif
+
+	/* Put the original return address in r4 as parent_ip */
+	mr	r4, r0
+
+	/* Load &pt_regs in r6 for call below */
+	addi    r6, r1, STACK_INT_FRAME_REGS
+.endm
+
+.macro	ftrace_regs_exit allregs
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
+	/* Check orig_gpr3 to detect ftrace_direct call */
+	PPC_LL	r3, ORIG_GPR3(r1)
+	PPC_LCMPI cr1, r3, 0
+	mtctr	r3
+#endif
+
+	/* Restore possibly modified LR */
+	PPC_LL	r0, _LINK(r1)
+
+#ifndef CONFIG_PPC_FTRACE_OUT_OF_LINE
+	/* Load ctr with the possibly modified NIP */
+	PPC_LL	r3, _NIP(r1)
+#ifdef CONFIG_LIVEPATCH_64
+	cmpd	r14, r3		/* has NIP been altered? */
+#endif
+
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
+	beq	cr1,2f
+	mtlr	r3
+	b	3f
+#endif
+2:	mtctr	r3
+	mtlr	r0
+3:
+
+#else /* !CONFIG_PPC_FTRACE_OUT_OF_LINE */
+	/* Load LR with the possibly modified NIP */
+	PPC_LL	r3, _NIP(r1)
+	cmpd	r14, r3		/* has NIP been altered? */
+	bne-	1f
+
+	mr	r3, r15
+1:	mtlr	r3
+	.if \allregs == 0
+	REST_GPR(15, r1)
+	.endif
+#endif
+
+	/* Restore gprs */
+	.if \allregs == 1
+	REST_GPRS(2, 31, r1)
+	.else
+	REST_GPRS(3, 10, r1)
+#if defined(CONFIG_LIVEPATCH_64) || defined(CONFIG_PPC_FTRACE_OUT_OF_LINE)
+	REST_GPR(14, r1)
+#endif
+	.endif
+
+#ifdef CONFIG_PPC64
+	/* Restore callee's TOC */
+	ld	r2, STK_GOT(r1)
+#endif
+
+	/* Pop our stack frame */
+	addi r1, r1, SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE
+
+#ifdef CONFIG_LIVEPATCH_64
+        /* Based on the cmpd above, if the NIP was altered handle livepatch */
+	bne-	livepatch_handler
+#endif
+
+	/* jump after _mcount site */
+#ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
+	bnectr	cr1
+#endif
+	/*
+	 * Return with blr to keep the link stack balanced. The function profiling sequence
+	 * uses 'mtlr r0' to restore LR.
+	 */
+	blr
+#else
+	bctr
+#endif
+.endm
+
+.macro ftrace_regs_func allregs
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS
+	bctrl
+#else
+	.if \allregs == 1
+.globl ftrace_regs_call
+ftrace_regs_call:
+	.else
+.globl ftrace_call
+ftrace_call:
+	.endif
+	/* ftrace_call(r3, r4, r5, r6) */
+	bl	ftrace_stub
+#endif
+.endm
+
+_GLOBAL(ftrace_regs_caller)
+	ftrace_regs_entry 1
+	ftrace_regs_func 1
+	ftrace_regs_exit 1
+
+_GLOBAL(ftrace_caller)
+	ftrace_regs_entry 0
+	ftrace_regs_func 0
+	ftrace_regs_exit 0
+
+_GLOBAL(ftrace_stub)
+	blr
+
+#ifdef CONFIG_PPC64
+ftrace_no_trace:
+#ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE
+	REST_GPR(3, r1)
+	addi	r1, r1, SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE
+	blr
+#else
+	mflr	r3
+	mtctr	r3
+	REST_GPR(3, r1)
+	addi	r1, r1, SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE
+	mtlr	r0
+	bctr
+#endif
+#endif
+
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
+.Lftrace_direct_call_regs:
+	mtctr	r12
+	REST_GPRS(11, 12, r1)
+	addi	r1, r1, SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE
+	bctr
+.Lftrace_direct_call:
+	mtctr	r12
+	addi	r1, r1, SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE
+	bctr
+SYM_FUNC_START(ftrace_stub_direct_tramp)
+	blr
+SYM_FUNC_END(ftrace_stub_direct_tramp)
+#endif
+
+#ifdef CONFIG_LIVEPATCH_64
+	/*
+	 * This function runs in the mcount context, between two functions. As
+	 * such it can only clobber registers which are volatile and used in
+	 * function linkage.
+	 *
+	 * We get here when a function A, calls another function B, but B has
+	 * been live patched with a new function C.
+	 *
+	 * On entry, we have no stack frame and can not allocate one.
+	 *
+	 * With PPC_FTRACE_OUT_OF_LINE=n, on entry:
+	 *  - LR points back to the original caller (in A)
+	 *  - CTR holds the new NIP in C
+	 *  - r0, r11 & r12 are free
+	 *
+	 * With PPC_FTRACE_OUT_OF_LINE=y, on entry:
+	 *  - r0 points back to the original caller (in A)
+	 *  - LR holds the new NIP in C
+	 *  - r11 & r12 are free
+	 */
+livepatch_handler:
+	ld	r12, PACA_THREAD_INFO(r13)
+
+	/* Allocate 3 x 8 bytes */
+	ld	r11, TI_livepatch_sp(r12)
+	addi	r11, r11, 24
+	std	r11, TI_livepatch_sp(r12)
+
+	/* Store stack end marker */
+	lis     r12, STACK_END_MAGIC@h
+	ori     r12, r12, STACK_END_MAGIC@l
+	std	r12, -8(r11)
+
+	/* Save toc & real LR on livepatch stack */
+	std	r2,  -24(r11)
+#ifndef CONFIG_PPC_FTRACE_OUT_OF_LINE
+	mflr	r12
+	std	r12, -16(r11)
+	mfctr	r12
+#else
+	std	r0, -16(r11)
+	mflr	r12
+	/* Put ctr in r12 for global entry and branch there */
+	mtctr	r12
+#endif
+	bctrl
+
+	/*
+	 * Now we are returning from the patched function to the original
+	 * caller A. We are free to use r11, r12 and we can use r2 until we
+	 * restore it.
+	 */
+
+	ld	r12, PACA_THREAD_INFO(r13)
+
+	ld	r11, TI_livepatch_sp(r12)
+
+	/* Check stack marker hasn't been trashed */
+	lis     r2,  STACK_END_MAGIC@h
+	ori     r2,  r2, STACK_END_MAGIC@l
+	ld	r12, -8(r11)
+1:	tdne	r12, r2
+	EMIT_BUG_ENTRY 1b, __FILE__, __LINE__ - 1, 0
+
+	/* Restore LR & toc from livepatch stack */
+	ld	r12, -16(r11)
+	mtlr	r12
+	ld	r2,  -24(r11)
+
+	/* Pop livepatch stack frame */
+	ld	r12, PACA_THREAD_INFO(r13)
+	subi	r11, r11, 24
+	std	r11, TI_livepatch_sp(r12)
+
+	/* Return to original caller of live patched function */
+	blr
+#endif /* CONFIG_LIVEPATCH */
+
+#ifndef CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY
+_GLOBAL(mcount)
+_GLOBAL(_mcount)
+EXPORT_SYMBOL(_mcount)
+	mflr	r12
+	mtctr	r12
+	mtlr	r0
+	bctr
+#endif
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+_GLOBAL(return_to_handler)
+	/* need to save return values */
+#ifdef CONFIG_PPC64
+	stdu	r1, -SWITCH_FRAME_SIZE(r1)
+	std	r4, GPR4(r1)
+	std	r3, GPR3(r1)
+	/* Save previous stack pointer (r1) */
+	addi	r3, r1, SWITCH_FRAME_SIZE
+	std	r3, GPR1(r1)
+	/* save TOC */
+	std	r2,  24(r1)
+	std	r31, 32(r1)
+	mr	r31, r1
+	/* pass ftrace_regs/pt_regs to ftrace_return_to_handler */
+	addi	r3, r1, STACK_INT_FRAME_REGS
+	/*
+	 * We might be called from a module.
+	 * Switch to our TOC to run inside the core kernel.
+	 */
+	LOAD_PACA_TOC()
+#else
+	stwu	r1, -SWITCH_FRAME_SIZE(r1)
+	stw	r4, GPR4(r1)
+	stw	r3, GPR3(r1)
+	addi	r3, r1, SWITCH_FRAME_SIZE
+	stw	r3, GPR1(r1)
+	/* pass ftrace_regs/pt_regs to ftrace_return_to_handler */
+	addi	r3, r1, STACK_INT_FRAME_REGS
+#endif
+
+	bl	ftrace_return_to_handler
+	nop
+
+	/* return value has real return address */
+	mtlr	r3
+
+#ifdef CONFIG_PPC64
+	ld	r4,  GPR4(r1)
+	ld	r3,  GPR3(r1)
+	ld	r2,  24(r1)
+	ld	r31, 32(r1)
+	ld	r1,  0(r1)
+#else
+	lwz	r3, GPR3(r1)
+	lwz	r4, GPR4(r1)
+	addi	r1, r1, SWITCH_FRAME_SIZE
+#endif
+
+	/* Jump back to real return address */
+	blr
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
+
+#ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE
+SYM_DATA(ftrace_ool_stub_text_count, .long CONFIG_PPC_FTRACE_OUT_OF_LINE_NUM_RESERVE)
+
+SYM_START(ftrace_ool_stub_text, SYM_L_GLOBAL, .balign SZL)
+	.space CONFIG_PPC_FTRACE_OUT_OF_LINE_NUM_RESERVE * FTRACE_OOL_STUB_SIZE
+SYM_CODE_END(ftrace_ool_stub_text)
+#endif
+
+.pushsection ".tramp.ftrace.text","aw",@progbits;
+.globl ftrace_tramp_text
+ftrace_tramp_text:
+	.space 32
+.popsection
+
+.pushsection ".tramp.ftrace.init","aw",@progbits;
+.globl ftrace_tramp_init
+ftrace_tramp_init:
+	.space 32
+.popsection

linux-7.2.3/arch/powerpc/kernel/trace/trace_clock.c

@@ -0,0 +1,13 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *
+ * Copyright (C) 2015 Naveen N. Rao, IBM Corporation
+ */
+
+#include <asm/trace_clock.h>
+#include <asm/time.h>
+
+u64 notrace trace_clock_ppc_tb(void)
+{
+	return get_tb();
+}