1 files changed, 48 insertions, 34 deletions

diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c
index 8745175f4a75..5cf990d052ba 100644
--- a/arch/arm64/kernel/ftrace.c
+++ b/arch/arm64/kernel/ftrace.c
@@ -17,6 +17,49 @@
 #include <asm/insn.h>
 #include <asm/patching.h>
 
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_ARGS
+struct fregs_offset {
+	const char *name;
+	int offset;
+};
+
+#define FREGS_OFFSET(n, field)				\
+{							\
+	.name = n,					\
+	.offset = offsetof(struct ftrace_regs, field),	\
+}
+
+static const struct fregs_offset fregs_offsets[] = {
+	FREGS_OFFSET("x0", regs[0]),
+	FREGS_OFFSET("x1", regs[1]),
+	FREGS_OFFSET("x2", regs[2]),
+	FREGS_OFFSET("x3", regs[3]),
+	FREGS_OFFSET("x4", regs[4]),
+	FREGS_OFFSET("x5", regs[5]),
+	FREGS_OFFSET("x6", regs[6]),
+	FREGS_OFFSET("x7", regs[7]),
+	FREGS_OFFSET("x8", regs[8]),
+
+	FREGS_OFFSET("x29", fp),
+	FREGS_OFFSET("x30", lr),
+	FREGS_OFFSET("lr", lr),
+
+	FREGS_OFFSET("sp", sp),
+	FREGS_OFFSET("pc", pc),
+};
+
+int ftrace_regs_query_register_offset(const char *name)
+{
+	for (int i = 0; i < ARRAY_SIZE(fregs_offsets); i++) {
+		const struct fregs_offset *roff = &fregs_offsets[i];
+		if (!strcmp(roff->name, name))
+			return roff->offset;
+	}
+
+	return -EINVAL;
+}
+#endif
+
 #ifdef CONFIG_DYNAMIC_FTRACE
 /*
  * Replace a single instruction, which may be a branch or NOP.
@@ -70,9 +113,6 @@ static struct plt_entry *get_ftrace_plt(struct module *mod, unsigned long addr)
 
 	if (addr == FTRACE_ADDR)
 		return &plt[FTRACE_PLT_IDX];
-	if (addr == FTRACE_REGS_ADDR &&
-	    IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS))
-		return &plt[FTRACE_REGS_PLT_IDX];
 #endif
 	return NULL;
 }
@@ -154,25 +194,7 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
 	return ftrace_modify_code(pc, old, new, true);
 }
 
-#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
-int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
-			unsigned long addr)
-{
-	unsigned long pc = rec->ip;
-	u32 old, new;
-
-	if (!ftrace_find_callable_addr(rec, NULL, &old_addr))
-		return -EINVAL;
-	if (!ftrace_find_callable_addr(rec, NULL, &addr))
-		return -EINVAL;
-
-	old = aarch64_insn_gen_branch_imm(pc, old_addr,
-					  AARCH64_INSN_BRANCH_LINK);
-	new = aarch64_insn_gen_branch_imm(pc, addr, AARCH64_INSN_BRANCH_LINK);
-
-	return ftrace_modify_code(pc, old, new, true);
-}
-
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_ARGS
 /*
  * The compiler has inserted two NOPs before the regular function prologue.
  * All instrumented functions follow the AAPCS, so x0-x8 and x19-x30 are live,
@@ -228,7 +250,7 @@ int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec,
 	 *
 	 * Note: 'mod' is only set at module load time.
 	 */
-	if (!IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) &&
+	if (!IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_ARGS) &&
 	    IS_ENABLED(CONFIG_ARM64_MODULE_PLTS) && mod) {
 		return aarch64_insn_patch_text_nosync((void *)pc, new);
 	}
@@ -279,19 +301,11 @@ void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent,
 
 #ifdef CONFIG_DYNAMIC_FTRACE
 
-#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
+#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)
 {
-	/*
-	 * When DYNAMIC_FTRACE_WITH_REGS is selected, `fregs` can never be NULL
-	 * and arch_ftrace_get_regs(fregs) will always give a non-NULL pt_regs
-	 * in which we can safely modify the LR.
-	 */
-	struct pt_regs *regs = arch_ftrace_get_regs(fregs);
-	unsigned long *parent = (unsigned long *)&procedure_link_pointer(regs);
-
-	prepare_ftrace_return(ip, parent, frame_pointer(regs));
+	prepare_ftrace_return(ip, &fregs->lr, fregs->fp);
 }
 #else
 /*
@@ -323,6 +337,6 @@ int ftrace_disable_ftrace_graph_caller(void)
 {
 	return ftrace_modify_graph_caller(false);
 }
-#endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */
+#endif /* CONFIG_DYNAMIC_FTRACE_WITH_ARGS */
 #endif /* CONFIG_DYNAMIC_FTRACE */
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */