1 files changed, 393 insertions, 0 deletions

diff --git a/arch/parisc/kernel/unwind.c b/arch/parisc/kernel/unwind.c
new file mode 100644
index 0000000..db14110
--- /dev/null
+++ b/arch/parisc/kernel/unwind.c
@@ -0,0 +1,393 @@
+/*
+ * Kernel unwinding support
+ *
+ * (c) 2002-2004 Randolph Chung <tausq@debian.org>
+ *
+ * Derived partially from the IA64 implementation. The PA-RISC
+ * Runtime Architecture Document is also a useful reference to
+ * understand what is happening here
+ */
+
+#include <linux/config.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/kallsyms.h>
+
+#include <asm/uaccess.h>
+#include <asm/assembly.h>
+
+#include <asm/unwind.h>
+
+/* #define DEBUG 1 */
+#ifdef DEBUG
+#define dbg(x...) printk(x)
+#else
+#define dbg(x...)
+#endif
+
+extern struct unwind_table_entry __start___unwind[];
+extern struct unwind_table_entry __stop___unwind[];
+
+static spinlock_t 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;
+static LIST_HEAD(unwind_tables);
+
+static inline const struct unwind_table_entry *
+find_unwind_entry_in_table(const struct unwind_table *table, unsigned long addr)
+{
+	const struct unwind_table_entry *e = NULL;
+	unsigned long lo, hi, mid;
+
+	lo = 0; 
+	hi = table->length - 1; 
+	
+	while (lo <= hi) {
+		mid = (hi - lo) / 2 + lo;
+		e = &table->table[mid];
+		if (addr < e->region_start)
+			hi = mid - 1;
+		else if (addr > e->region_end)
+			lo = mid + 1;
+		else
+			return e;
+	}
+
+	return NULL;
+}
+
+static const struct unwind_table_entry *
+find_unwind_entry(unsigned long addr)
+{
+	struct unwind_table *table;
+	const struct unwind_table_entry *e = NULL;
+
+	if (addr >= kernel_unwind_table.start && 
+	    addr <= kernel_unwind_table.end)
+		e = find_unwind_entry_in_table(&kernel_unwind_table, addr);
+	else 
+		list_for_each_entry(table, &unwind_tables, list) {
+			if (addr >= table->start && 
+			    addr <= table->end)
+				e = find_unwind_entry_in_table(table, addr);
+			if (e)
+				break;
+		}
+
+	return e;
+}
+
+static void
+unwind_table_init(struct unwind_table *table, const char *name,
+		  unsigned long base_addr, unsigned long gp,
+		  void *table_start, void *table_end)
+{
+	struct unwind_table_entry *start = table_start;
+	struct unwind_table_entry *end = 
+		(struct unwind_table_entry *)table_end - 1;
+
+	table->name = name;
+	table->base_addr = base_addr;
+	table->gp = gp;
+	table->start = base_addr + start->region_start;
+	table->end = base_addr + end->region_end;
+	table->table = (struct unwind_table_entry *)table_start;
+	table->length = end - start + 1;
+	INIT_LIST_HEAD(&table->list);
+
+	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);
+		}
+
+		start->region_start += base_addr;
+		start->region_end += base_addr;
+	}
+}
+
+static void
+unwind_table_sort(struct unwind_table_entry *start,
+		  struct unwind_table_entry *finish)
+{
+	struct unwind_table_entry el, *p, *q;
+
+	for (p = start + 1; p < finish; ++p) {
+		if (p[0].region_start < p[-1].region_start) {
+			el = *p;
+			q = p;
+			do {
+				q[0] = q[-1];
+				--q;
+			} while (q > start && 
+				 el.region_start < q[-1].region_start);
+			*q = el;
+		}
+	}
+}
+
+struct unwind_table *
+unwind_table_add(const char *name, unsigned long base_addr, 
+		 unsigned long gp,
+                 void *start, void *end)
+{
+	struct unwind_table *table;
+	unsigned long flags;
+	struct unwind_table_entry *s = (struct unwind_table_entry *)start;
+	struct unwind_table_entry *e = (struct unwind_table_entry *)end;
+
+	unwind_table_sort(s, e);
+
+	table = kmalloc(sizeof(struct unwind_table), GFP_USER);
+	if (table == NULL)
+		return NULL;
+	unwind_table_init(table, name, base_addr, gp, start, end);
+	spin_lock_irqsave(&unwind_lock, flags);
+	list_add_tail(&table->list, &unwind_tables);
+	spin_unlock_irqrestore(&unwind_lock, flags);
+
+	return table;
+}
+
+void unwind_table_remove(struct unwind_table *table)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&unwind_lock, flags);
+	list_del(&table->list);
+	spin_unlock_irqrestore(&unwind_lock, flags);
+
+	kfree(table);
+}
+
+/* Called from setup_arch to import the kernel unwind info */
+static int unwind_init(void)
+{
+	long start, stop;
+	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", 
+	    start, stop,
+	    (stop - start) / sizeof(struct unwind_table_entry));
+
+	unwind_table_init(&kernel_unwind_table, "kernel", KERNEL_START,
+			  gp, 
+			  &__start___unwind[0], &__stop___unwind[0]);
+#if 0
+	{
+		int i;
+		for (i = 0; i < 10; i++)
+		{
+			printk("region 0x%x-0x%x\n", 
+				__start___unwind[i].region_start, 
+				__start___unwind[i].region_end);
+		}
+	}
+#endif
+	return 0;
+}
+
+static void unwind_frame_regs(struct unwind_frame_info *info)
+{
+	const struct unwind_table_entry *e;
+	unsigned long npc;
+	unsigned int insn;
+	long frame_size = 0;
+	int looking_for_rp, rpoffset = 0;
+
+	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+1];
+			char *modname;
+			unsigned long symsize, offset;
+
+			kallsyms_lookup(info->ip, &symsize, &offset,
+					&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
+
+		/* Since we are doing the unwinding blind, we don't know if
+		   we are adjusting the stack correctly or extracting the rp
+		   correctly. The rp is checked to see if it belongs to the
+		   kernel text section, if not we assume we don't have a 
+		   correct stack frame and we continue to unwind the stack.
+		   This is not quite correct, and will fail for loadable
+		   modules. */
+		sp = info->sp & ~63;
+		do {
+			unsigned long tmp;
+
+			info->prev_sp = sp - 64;
+			info->prev_ip = 0;
+			if (get_user(tmp, (unsigned long *)(info->prev_sp - RP_OFFSET))) 
+				break;
+			info->prev_ip = tmp;
+			sp = info->prev_sp;
+		} while (info->prev_ip < (unsigned long)_stext ||
+			 info->prev_ip > (unsigned long)_etext);
+
+		info->rp = 0;
+
+		dbg("analyzing func @ %lx with no unwind info, setting "
+		    "prev_sp=%lx prev_ip=%lx\n", info->ip, 
+		    info->prev_sp, info->prev_ip);
+	} else {
+		dbg("e->start = 0x%x, e->end = 0x%x, Save_SP = %d, "
+		    "Save_RP = %d, Millicode = %d size = %u\n", 
+		    e->region_start, e->region_end, e->Save_SP, e->Save_RP, 
+		    e->Millicode, e->Total_frame_size);
+
+		looking_for_rp = e->Save_RP;
+
+		for (npc = e->region_start; 
+		     (frame_size < (e->Total_frame_size << 3) || 
+		      looking_for_rp) && 
+		     npc < info->ip; 
+		     npc += 4) {
+
+			insn = *(unsigned int *)npc;
+
+			if ((insn & 0xffffc000) == 0x37de0000 ||
+			    (insn & 0xffe00000) == 0x6fc00000) {
+				/* ldo X(sp), sp, or stwm X,D(sp) */
+				frame_size += (insn & 0x1 ? -1 << 13 : 0) | 
+					((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) {
+				/* std,ma X,D(sp) */
+				frame_size += (insn & 0x1 ? -1 << 13 : 0) | 
+					(((insn >> 4) & 0x3ff) << 3);
+				dbg("analyzing func @ %lx, insn=%08x @ "
+				    "%lx, frame_size = %ld\n", info->ip,
+				    insn, npc, frame_size);
+			} else if (insn == 0x6bc23fd9) { 
+				/* stw rp,-20(sp) */
+				rpoffset = 20;
+				looking_for_rp = 0;
+				dbg("analyzing func @ %lx, insn=stw rp,"
+				    "-20(sp) @ %lx\n", info->ip, npc);
+			} else if (insn == 0x0fc212c1) {
+				/* std rp,-16(sr0,sp) */
+				rpoffset = 16;
+				looking_for_rp = 0;
+				dbg("analyzing func @ %lx, insn=std rp,"
+				    "-16(sp) @ %lx\n", info->ip, npc);
+			}
+		}
+
+		info->prev_sp = info->sp - frame_size;
+		if (e->Millicode)
+			info->rp = info->r31;
+		else if (rpoffset)
+			info->rp = *(unsigned long *)(info->prev_sp - rpoffset);
+		info->prev_ip = info->rp;
+		info->rp = 0;
+
+		dbg("analyzing func @ %lx, setting prev_sp=%lx "
+		    "prev_ip=%lx npc=%lx\n", info->ip, info->prev_sp, 
+		    info->prev_ip, npc);
+	}
+}
+
+void unwind_frame_init(struct unwind_frame_info *info, struct task_struct *t, 
+		       struct pt_regs *regs)
+{
+	memset(info, 0, sizeof(struct unwind_frame_info));
+	info->t = t;
+	info->sp = regs->gr[30];
+	info->ip = regs->iaoq[0];
+	info->rp = regs->gr[2];
+	info->r31 = regs->gr[31];
+
+	dbg("(%d) Start unwind from sp=%08lx ip=%08lx\n", 
+	    t ? (int)t->pid : -1, info->sp, info->ip);
+}
+
+void unwind_frame_init_from_blocked_task(struct unwind_frame_info *info, struct task_struct *t)
+{
+	struct pt_regs *r = &t->thread.regs;
+	struct pt_regs *r2;
+
+	r2 = (struct pt_regs *)kmalloc(sizeof(struct pt_regs), GFP_KERNEL);
+	if (!r2)
+		return;
+	*r2 = *r;
+	r2->gr[30] = r->ksp;
+	r2->iaoq[0] = r->kpc;
+	unwind_frame_init(info, t, r2);
+	kfree(r2);
+}
+
+void unwind_frame_init_running(struct unwind_frame_info *info, struct pt_regs *regs)
+{
+	unwind_frame_init(info, current, regs);
+}
+
+int unwind_once(struct unwind_frame_info *next_frame)
+{
+	unwind_frame_regs(next_frame);
+
+	if (next_frame->prev_sp == 0 ||
+	    next_frame->prev_ip == 0)
+		return -1;
+
+	next_frame->sp = next_frame->prev_sp;
+	next_frame->ip = next_frame->prev_ip;
+	next_frame->prev_sp = 0;
+	next_frame->prev_ip = 0;
+
+	dbg("(%d) Continue unwind to sp=%08lx ip=%08lx\n", 
+	    next_frame->t ? (int)next_frame->t->pid : -1, 
+	    next_frame->sp, next_frame->ip);
+
+	return 0;
+}
+
+int unwind_to_user(struct unwind_frame_info *info)
+{
+	int ret;
+	
+	do {
+		ret = unwind_once(info);
+	} while (!ret && !(info->ip & 3));
+
+	return ret;
+}
+
+module_init(unwind_init);