1 files changed, 152 insertions, 100 deletions

diff --git a/arch/loongarch/kernel/unwind_prologue.c b/arch/loongarch/kernel/unwind_prologue.c
index 0f8d1451ebb8..9095fde8e55d 100644
--- a/arch/loongarch/kernel/unwind_prologue.c
+++ b/arch/loongarch/kernel/unwind_prologue.c
@@ -2,61 +2,116 @@
 /*
  * Copyright (C) 2022 Loongson Technology Corporation Limited
  */
+#include <linux/cpumask.h>
 #include <linux/ftrace.h>
 #include <linux/kallsyms.h>
 
 #include <asm/inst.h>
+#include <asm/loongson.h>
 #include <asm/ptrace.h>
+#include <asm/setup.h>
 #include <asm/unwind.h>
 
-static inline void unwind_state_fixup(struct unwind_state *state)
-{
-#ifdef CONFIG_DYNAMIC_FTRACE
-	static unsigned long ftrace = (unsigned long)ftrace_call + 4;
-
-	if (state->pc == ftrace)
-		state->is_ftrace = true;
+extern const int unwind_hint_ade;
+extern const int unwind_hint_ale;
+extern const int unwind_hint_bp;
+extern const int unwind_hint_fpe;
+extern const int unwind_hint_fpu;
+extern const int unwind_hint_lsx;
+extern const int unwind_hint_lasx;
+extern const int unwind_hint_lbt;
+extern const int unwind_hint_ri;
+extern const int unwind_hint_watch;
+extern unsigned long eentry;
+#ifdef CONFIG_NUMA
+extern unsigned long pcpu_handlers[NR_CPUS];
 #endif
-}
 
-unsigned long unwind_get_return_address(struct unwind_state *state)
+static inline bool scan_handlers(unsigned long entry_offset)
 {
+	int idx, offset;
 
-	if (unwind_done(state))
-		return 0;
-	else if (state->type)
-		return state->pc;
-	else if (state->first)
-		return state->pc;
-
-	return *(unsigned long *)(state->sp);
+	if (entry_offset >= EXCCODE_INT_START * VECSIZE)
+		return false;
 
+	idx = entry_offset / VECSIZE;
+	offset = entry_offset % VECSIZE;
+	switch (idx) {
+	case EXCCODE_ADE:
+		return offset == unwind_hint_ade;
+	case EXCCODE_ALE:
+		return offset == unwind_hint_ale;
+	case EXCCODE_BP:
+		return offset == unwind_hint_bp;
+	case EXCCODE_FPE:
+		return offset == unwind_hint_fpe;
+	case EXCCODE_FPDIS:
+		return offset == unwind_hint_fpu;
+	case EXCCODE_LSXDIS:
+		return offset == unwind_hint_lsx;
+	case EXCCODE_LASXDIS:
+		return offset == unwind_hint_lasx;
+	case EXCCODE_BTDIS:
+		return offset == unwind_hint_lbt;
+	case EXCCODE_INE:
+		return offset == unwind_hint_ri;
+	case EXCCODE_WATCH:
+		return offset == unwind_hint_watch;
+	default:
+		return false;
+	}
 }
-EXPORT_SYMBOL_GPL(unwind_get_return_address);
 
-static bool unwind_by_guess(struct unwind_state *state)
+static inline bool fix_exception(unsigned long pc)
 {
-	struct stack_info *info = &state->stack_info;
-	unsigned long addr;
-
-	for (state->sp += sizeof(unsigned long);
-	     state->sp < info->end;
-	     state->sp += sizeof(unsigned long)) {
-		addr = *(unsigned long *)(state->sp);
-		state->pc = ftrace_graph_ret_addr(state->task, &state->graph_idx,
-				addr, (unsigned long *)(state->sp - GRAPH_FAKE_OFFSET));
-		if (__kernel_text_address(addr))
+#ifdef CONFIG_NUMA
+	int cpu;
+
+	for_each_possible_cpu(cpu) {
+		if (!pcpu_handlers[cpu])
+			continue;
+		if (scan_handlers(pc - pcpu_handlers[cpu]))
 			return true;
 	}
+#endif
+	return scan_handlers(pc - eentry);
+}
 
+/*
+ * As we meet ftrace_regs_entry, reset first flag like first doing
+ * tracing. Prologue analysis will stop soon because PC is at entry.
+ */
+static inline bool fix_ftrace(unsigned long pc)
+{
+#ifdef CONFIG_DYNAMIC_FTRACE
+	return pc == (unsigned long)ftrace_call + LOONGARCH_INSN_SIZE;
+#else
 	return false;
+#endif
 }
 
+static inline bool unwind_state_fixup(struct unwind_state *state)
+{
+	if (!fix_exception(state->pc) && !fix_ftrace(state->pc))
+		return false;
+
+	state->reset = true;
+	return true;
+}
+
+/*
+ * LoongArch function prologue is like follows,
+ *     [instructions not use stack var]
+ *     addi.d sp, sp, -imm
+ *     st.d   xx, sp, offset <- save callee saved regs and
+ *     st.d   yy, sp, offset    save ra if function is nest.
+ *     [others instructions]
+ */
 static bool unwind_by_prologue(struct unwind_state *state)
 {
 	long frame_ra = -1;
 	unsigned long frame_size = 0;
-	unsigned long size, offset, pc = state->pc;
+	unsigned long size, offset, pc;
 	struct pt_regs *regs;
 	struct stack_info *info = &state->stack_info;
 	union loongarch_instruction *ip, *ip_end;
@@ -64,20 +119,21 @@ static bool unwind_by_prologue(struct unwind_state *state)
 	if (state->sp >= info->end || state->sp < info->begin)
 		return false;
 
-	if (state->is_ftrace) {
-		/*
-		 * As we meet ftrace_regs_entry, reset first flag like first doing
-		 * tracing. Prologue analysis will stop soon because PC is at entry.
-		 */
+	if (state->reset) {
 		regs = (struct pt_regs *)state->sp;
 		state->first = true;
-		state->is_ftrace = false;
+		state->reset = false;
 		state->pc = regs->csr_era;
 		state->ra = regs->regs[1];
 		state->sp = regs->regs[3];
 		return true;
 	}
 
+	/*
+	 * When first is not set, the PC is a return address in the previous frame.
+	 * We need to adjust its value in case overflow to the next symbol.
+	 */
+	pc = state->pc - (state->first ? 0 : LOONGARCH_INSN_SIZE);
 	if (!kallsyms_lookup_size_offset(pc, &size, &offset))
 		return false;
 
@@ -93,6 +149,10 @@ static bool unwind_by_prologue(struct unwind_state *state)
 		ip++;
 	}
 
+	/*
+	 * Can't find stack alloc action, PC may be in a leaf function. Only the
+	 * first being true is reasonable, otherwise indicate analysis is broken.
+	 */
 	if (!frame_size) {
 		if (state->first)
 			goto first;
@@ -110,6 +170,7 @@ static bool unwind_by_prologue(struct unwind_state *state)
 		ip++;
 	}
 
+	/* Can't find save $ra action, PC may be in a leaf function, too. */
 	if (frame_ra < 0) {
 		if (state->first) {
 			state->sp = state->sp + frame_size;
@@ -118,88 +179,47 @@ static bool unwind_by_prologue(struct unwind_state *state)
 		return false;
 	}
 
-	if (state->first)
-		state->first = false;
-
 	state->pc = *(unsigned long *)(state->sp + frame_ra);
 	state->sp = state->sp + frame_size;
 	goto out;
 
 first:
-	state->first = false;
-	if (state->pc == state->ra)
-		return false;
-
 	state->pc = state->ra;
 
 out:
-	unwind_state_fixup(state);
-	return !!__kernel_text_address(state->pc);
-}
-
-void unwind_start(struct unwind_state *state, struct task_struct *task,
-		    struct pt_regs *regs)
-{
-	memset(state, 0, sizeof(*state));
-
-	if (regs &&  __kernel_text_address(regs->csr_era)) {
-		state->pc = regs->csr_era;
-		state->sp = regs->regs[3];
-		state->ra = regs->regs[1];
-		state->type = UNWINDER_PROLOGUE;
-	}
-
-	state->task = task;
-	state->first = true;
-
-	get_stack_info(state->sp, state->task, &state->stack_info);
-
-	if (!unwind_done(state) && !__kernel_text_address(state->pc))
-		unwind_next_frame(state);
+	state->first = false;
+	return unwind_state_fixup(state) || __kernel_text_address(state->pc);
 }
-EXPORT_SYMBOL_GPL(unwind_start);
 
-bool unwind_next_frame(struct unwind_state *state)
+static bool next_frame(struct unwind_state *state)
 {
-	struct stack_info *info = &state->stack_info;
-	struct pt_regs *regs;
 	unsigned long pc;
+	struct pt_regs *regs;
+	struct stack_info *info = &state->stack_info;
 
 	if (unwind_done(state))
 		return false;
 
 	do {
-		switch (state->type) {
-		case UNWINDER_GUESS:
-			state->first = false;
-			if (unwind_by_guess(state))
-				return true;
-			break;
+		if (unwind_by_prologue(state)) {
+			state->pc = unwind_graph_addr(state, state->pc, state->sp);
+			return true;
+		}
+
+		if (info->type == STACK_TYPE_IRQ && info->end == state->sp) {
+			regs = (struct pt_regs *)info->next_sp;
+			pc = regs->csr_era;
+
+			if (user_mode(regs) || !__kernel_text_address(pc))
+				return false;
+
+			state->first = true;
+			state->pc = pc;
+			state->ra = regs->regs[1];
+			state->sp = regs->regs[3];
+			get_stack_info(state->sp, state->task, info);
 
-		case UNWINDER_PROLOGUE:
-			if (unwind_by_prologue(state)) {
-				state->pc = ftrace_graph_ret_addr(state->task, &state->graph_idx,
-						state->pc, (unsigned long *)(state->sp - GRAPH_FAKE_OFFSET));
-				return true;
-			}
-
-			if (info->type == STACK_TYPE_IRQ &&
-				info->end == state->sp) {
-				regs = (struct pt_regs *)info->next_sp;
-				pc = regs->csr_era;
-
-				if (user_mode(regs) || !__kernel_text_address(pc))
-					return false;
-
-				state->first = true;
-				state->ra = regs->regs[1];
-				state->sp = regs->regs[3];
-				state->pc = ftrace_graph_ret_addr(state->task, &state->graph_idx,
-						pc, (unsigned long *)(state->sp - GRAPH_FAKE_OFFSET));
-				get_stack_info(state->sp, state->task, info);
-
-				return true;
-			}
+			return true;
 		}
 
 		state->sp = info->next_sp;
@@ -208,4 +228,36 @@ bool unwind_next_frame(struct unwind_state *state)
 
 	return false;
 }
+
+unsigned long unwind_get_return_address(struct unwind_state *state)
+{
+	return __unwind_get_return_address(state);
+}
+EXPORT_SYMBOL_GPL(unwind_get_return_address);
+
+void unwind_start(struct unwind_state *state, struct task_struct *task,
+		    struct pt_regs *regs)
+{
+	__unwind_start(state, task, regs);
+	state->type = UNWINDER_PROLOGUE;
+	state->first = true;
+
+	/*
+	 * The current PC is not kernel text address, we cannot find its
+	 * relative symbol. Thus, prologue analysis will be broken. Luckily,
+	 * we can use the default_next_frame().
+	 */
+	if (!__kernel_text_address(state->pc)) {
+		state->type = UNWINDER_GUESS;
+		if (!unwind_done(state))
+			unwind_next_frame(state);
+	}
+}
+EXPORT_SYMBOL_GPL(unwind_start);
+
+bool unwind_next_frame(struct unwind_state *state)
+{
+	return state->type == UNWINDER_PROLOGUE ?
+			next_frame(state) : default_next_frame(state);
+}
 EXPORT_SYMBOL_GPL(unwind_next_frame);