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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/parisc/kernel/unwind.c
downloadleg-kernel-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'arch/parisc/kernel/unwind.c')
-rw-r--r--arch/parisc/kernel/unwind.c393
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 000000000000..db141108412e
--- /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);