1 files changed, 127 insertions, 75 deletions

diff --git a/arch/parisc/kernel/unwind.c b/arch/parisc/kernel/unwind.c
index 76ed62ed785b..7ac88ff13d3c 100644
--- a/arch/parisc/kernel/unwind.c
+++ b/arch/parisc/kernel/unwind.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * Kernel unwinding support
  *
@@ -12,35 +13,40 @@
 #include <linux/init.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
-#include <linux/kallsyms.h>
 #include <linux/sort.h>
+#include <linux/sched/task_stack.h>
 
-#include <asm/uaccess.h>
+#include <linux/uaccess.h>
 #include <asm/assembly.h>
 #include <asm/asm-offsets.h>
 #include <asm/ptrace.h>
 
 #include <asm/unwind.h>
+#include <asm/switch_to.h>
+#include <asm/sections.h>
+#include <asm/ftrace.h>
 
 /* #define DEBUG 1 */
 #ifdef DEBUG
-#define dbg(x...) printk(x)
+#define dbg(x...) pr_debug(x)
 #else
-#define dbg(x...)
+#define dbg(x...) do { } while (0)
 #endif
 
 #define KERNEL_START (KERNEL_BINARY_TEXT_START)
 
+#define ALIGNMENT_OK(ptr, type) (((ptr) & (sizeof(type) - 1)) == 0)
+
 extern struct unwind_table_entry __start___unwind[];
 extern struct unwind_table_entry __stop___unwind[];
 
-static spinlock_t unwind_lock;
+static DEFINE_SPINLOCK(unwind_lock);
 /*
  * the kernel unwind block is not dynamically allocated so that
  * we can call unwind_init as early in the bootup process as 
  * possible (before the slab allocator is initialized)
  */
-static struct unwind_table kernel_unwind_table __read_mostly;
+static struct unwind_table kernel_unwind_table __ro_after_init;
 static LIST_HEAD(unwind_tables);
 
 static inline const struct unwind_table_entry *
@@ -75,7 +81,10 @@ find_unwind_entry(unsigned long addr)
 	if (addr >= kernel_unwind_table.start && 
 	    addr <= kernel_unwind_table.end)
 		e = find_unwind_entry_in_table(&kernel_unwind_table, addr);
-	else 
+	else {
+		unsigned long flags;
+
+		spin_lock_irqsave(&unwind_lock, flags);
 		list_for_each_entry(table, &unwind_tables, list) {
 			if (addr >= table->start && 
 			    addr <= table->end)
@@ -86,6 +95,8 @@ find_unwind_entry(unsigned long addr)
 				break;
 			}
 		}
+		spin_unlock_irqrestore(&unwind_lock, flags);
+	}
 
 	return e;
 }
@@ -111,7 +122,8 @@ unwind_table_init(struct unwind_table *table, const char *name,
 	for (; start <= end; start++) {
 		if (start < end && 
 		    start->region_end > (start+1)->region_start) {
-			printk("WARNING: Out of order unwind entry! %p and %p\n", start, start+1);
+			pr_warn("Out of order unwind entry! %px and %px\n",
+				start, start+1);
 		}
 
 		start->region_start += base_addr;
@@ -168,17 +180,15 @@ void unwind_table_remove(struct unwind_table *table)
 }
 
 /* Called from setup_arch to import the kernel unwind info */
-int unwind_init(void)
+int __init unwind_init(void)
 {
-	long start, stop;
+	long start __maybe_unused, stop __maybe_unused;
 	register unsigned long gp __asm__ ("r27");
 
 	start = (long)&__start___unwind[0];
 	stop = (long)&__stop___unwind[0];
 
-	spin_lock_init(&unwind_lock);
-
-	printk("unwind_init: start = 0x%lx, end = 0x%lx, entries = %lu\n", 
+	dbg("unwind_init: start = 0x%lx, end = 0x%lx, entries = %lu\n",
 	    start, stop,
 	    (stop - start) / sizeof(struct unwind_table_entry));
 
@@ -199,26 +209,70 @@ int unwind_init(void)
 	return 0;
 }
 
-#ifdef CONFIG_64BIT
-#define get_func_addr(fptr) fptr[2]
-#else
-#define get_func_addr(fptr) fptr[0]
-#endif
+static bool pc_is_kernel_fn(unsigned long pc, void *fn)
+{
+	return (unsigned long)dereference_kernel_function_descriptor(fn) == pc;
+}
 
 static int unwind_special(struct unwind_frame_info *info, unsigned long pc, int frame_size)
 {
-	extern void handle_interruption(int, struct pt_regs *);
-	static unsigned long *hi = (unsigned long *)&handle_interruption;
-
-	if (pc == get_func_addr(hi)) {
+	/*
+	 * We have to use void * instead of a function pointer, because
+	 * function pointers aren't a pointer to the function on 64-bit.
+	 * Make them const so the compiler knows they live in .text
+	 * Note: We could use dereference_kernel_function_descriptor()
+	 * instead but we want to keep it simple here.
+	 */
+	extern void * const ret_from_kernel_thread;
+	extern void * const syscall_exit;
+	extern void * const intr_return;
+	extern void * const _switch_to_ret;
+#ifdef CONFIG_IRQSTACKS
+	extern void * const _call_on_stack;
+#endif /* CONFIG_IRQSTACKS */
+
+	if (pc_is_kernel_fn(pc, handle_interruption)) {
 		struct pt_regs *regs = (struct pt_regs *)(info->sp - frame_size - PT_SZ_ALGN);
 		dbg("Unwinding through handle_interruption()\n");
 		info->prev_sp = regs->gr[30];
 		info->prev_ip = regs->iaoq[0];
+		return 1;
+	}
 
+	if (pc == (unsigned long)&ret_from_kernel_thread ||
+	    pc == (unsigned long)&syscall_exit) {
+		info->prev_sp = info->prev_ip = 0;
+		return 1;
+	}
+
+	if (pc == (unsigned long)&intr_return) {
+		struct pt_regs *regs;
+
+		dbg("Found intr_return()\n");
+		regs = (struct pt_regs *)(info->sp - PT_SZ_ALGN);
+		info->prev_sp = regs->gr[30];
+		info->prev_ip = regs->iaoq[0];
+		info->rp = regs->gr[2];
+		return 1;
+	}
+
+	if (pc_is_kernel_fn(pc, _switch_to) ||
+	    pc == (unsigned long)&_switch_to_ret) {
+		info->prev_sp = info->sp - CALLEE_SAVE_FRAME_SIZE;
+		if (ALIGNMENT_OK(info->prev_sp, long))
+			info->prev_ip = *(unsigned long *)(info->prev_sp - RP_OFFSET);
+		else
+			info->prev_ip = info->prev_sp = 0;
 		return 1;
 	}
 
+#ifdef CONFIG_IRQSTACKS
+	if (pc == (unsigned long)&_call_on_stack && ALIGNMENT_OK(info->sp, long)) {
+		info->prev_sp = *(unsigned long *)(info->sp - FRAME_SIZE - REG_SZ);
+		info->prev_ip = *(unsigned long *)(info->sp - FRAME_SIZE - RP_OFFSET);
+		return 1;
+	}
+#endif
 	return 0;
 }
 
@@ -233,36 +287,9 @@ static void unwind_frame_regs(struct unwind_frame_info *info)
 	e = find_unwind_entry(info->ip);
 	if (e == NULL) {
 		unsigned long sp;
-		extern char _stext[], _etext[];
 
-		dbg("Cannot find unwind entry for 0x%lx; forced unwinding\n", info->ip);
-
-#ifdef CONFIG_KALLSYMS
-		/* Handle some frequent special cases.... */
-		{
-			char symname[KSYM_NAME_LEN];
-			char *modname;
-
-			kallsyms_lookup(info->ip, NULL, NULL, &modname,
-				symname);
-
-			dbg("info->ip = 0x%lx, name = %s\n", info->ip, symname);
-
-			if (strcmp(symname, "_switch_to_ret") == 0) {
-				info->prev_sp = info->sp - CALLEE_SAVE_FRAME_SIZE;
-				info->prev_ip = *(unsigned long *)(info->prev_sp - RP_OFFSET);
-				dbg("_switch_to_ret @ %lx - setting "
-				    "prev_sp=%lx prev_ip=%lx\n", 
-				    info->ip, info->prev_sp, 
-				    info->prev_ip);
-				return;
-			} else if (strcmp(symname, "ret_from_kernel_thread") == 0 ||
-				   strcmp(symname, "syscall_exit") == 0) {
-				info->prev_ip = info->prev_sp = 0;
-				return;
-			}
-		}
-#endif
+		dbg("Cannot find unwind entry for %pS; forced unwinding\n",
+			(void *) info->ip);
 
 		/* Since we are doing the unwinding blind, we don't know if
 		   we are adjusting the stack correctly or extracting the rp
@@ -277,12 +304,20 @@ static void unwind_frame_regs(struct unwind_frame_info *info)
 
 			info->prev_sp = sp - 64;
 			info->prev_ip = 0;
-			if (get_user(tmp, (unsigned long *)(info->prev_sp - RP_OFFSET))) 
+
+			/* Check if stack is inside kernel stack area */
+			if ((info->prev_sp - (unsigned long) task_stack_page(info->t))
+					>= THREAD_SIZE) {
+				info->prev_sp = 0;
+				break;
+			}
+
+			if (copy_from_kernel_nofault(&tmp,
+			    (void *)info->prev_sp - RP_OFFSET, sizeof(tmp)))
 				break;
 			info->prev_ip = tmp;
 			sp = info->prev_sp;
-		} while (info->prev_ip < (unsigned long)_stext ||
-			 info->prev_ip > (unsigned long)_etext);
+		} while (!kernel_text_address(info->prev_ip));
 
 		info->rp = 0;
 
@@ -305,18 +340,16 @@ static void unwind_frame_regs(struct unwind_frame_info *info)
 
 			insn = *(unsigned int *)npc;
 
-			if ((insn & 0xffffc000) == 0x37de0000 ||
-			    (insn & 0xffe00000) == 0x6fc00000) {
+			if ((insn & 0xffffc001) == 0x37de0000 ||
+			    (insn & 0xffe00001) == 0x6fc00000) {
 				/* ldo X(sp), sp, or stwm X,D(sp) */
-				frame_size += (insn & 0x1 ? -1 << 13 : 0) | 
-					((insn & 0x3fff) >> 1);
+				frame_size += (insn & 0x3fff) >> 1;
 				dbg("analyzing func @ %lx, insn=%08x @ "
 				    "%lx, frame_size = %ld\n", info->ip,
 				    insn, npc, frame_size);
-			} else if ((insn & 0xffe00008) == 0x73c00008) {
+			} else if ((insn & 0xffe00009) == 0x73c00008) {
 				/* std,ma X,D(sp) */
-				frame_size += (insn & 0x1 ? -1 << 13 : 0) | 
-					(((insn >> 4) & 0x3ff) << 3);
+				frame_size += ((insn >> 4) & 0x3ff) << 3;
 				dbg("analyzing func @ %lx, insn=%08x @ "
 				    "%lx, frame_size = %ld\n", info->ip,
 				    insn, npc, frame_size);
@@ -335,12 +368,17 @@ static void unwind_frame_regs(struct unwind_frame_info *info)
 			}
 		}
 
+		if (frame_size > e->Total_frame_size << 3)
+			frame_size = e->Total_frame_size << 3;
+
 		if (!unwind_special(info, e->region_start, frame_size)) {
 			info->prev_sp = info->sp - frame_size;
 			if (e->Millicode)
 				info->rp = info->r31;
-			else if (rpoffset)
+			else if (rpoffset && ALIGNMENT_OK(info->prev_sp, long))
 				info->rp = *(unsigned long *)(info->prev_sp - rpoffset);
+			else
+				info->rp = 0;
 			info->prev_ip = info->rp;
 			info->rp = 0;
 		}
@@ -380,9 +418,31 @@ void unwind_frame_init_from_blocked_task(struct unwind_frame_info *info, struct
 	kfree(r2);
 }
 
-void unwind_frame_init_running(struct unwind_frame_info *info, struct pt_regs *regs)
+#define get_parisc_stackpointer() ({ \
+	unsigned long sp; \
+	__asm__("copy %%r30, %0" : "=r"(sp)); \
+	(sp); \
+})
+
+void unwind_frame_init_task(struct unwind_frame_info *info,
+	struct task_struct *task, struct pt_regs *regs)
 {
-	unwind_frame_init(info, current, regs);
+	task = task ? task : current;
+
+	if (task == current) {
+		struct pt_regs r;
+
+		if (!regs) {
+			memset(&r, 0, sizeof(r));
+			r.iaoq[0] =  _THIS_IP_;
+			r.gr[2] = _RET_IP_;
+			r.gr[30] = get_parisc_stackpointer();
+			regs = &r;
+		}
+		unwind_frame_init(info, task, regs);
+	} else {
+		unwind_frame_init_from_blocked_task(info, task);
+	}
 }
 
 int unwind_once(struct unwind_frame_info *next_frame)
@@ -419,25 +479,17 @@ int unwind_to_user(struct unwind_frame_info *info)
 unsigned long return_address(unsigned int level)
 {
 	struct unwind_frame_info info;
-	struct pt_regs r;
-	unsigned long sp;
 
 	/* initialize unwind info */
-	asm volatile ("copy %%r30, %0" : "=r"(sp));
-	memset(&r, 0, sizeof(struct pt_regs));
-	r.iaoq[0] = (unsigned long) current_text_addr();
-	r.gr[2] = (unsigned long) __builtin_return_address(0);
-	r.gr[30] = sp;
-	unwind_frame_init(&info, current, &r);
+	unwind_frame_init_task(&info, current, NULL);
 
 	/* unwind stack */
-	++level;
+	level += 2;
 	do {
 		if (unwind_once(&info) < 0 || info.ip == 0)
 			return 0;
-		if (!__kernel_text_address(info.ip)) {
+		if (!kernel_text_address(info.ip))
 			return 0;
-		}
 	} while (info.ip && level--);
 
 	return info.ip;