v4.19.13 snapshot.
diff --git a/arch/parisc/kernel/unwind.c b/arch/parisc/kernel/unwind.c
new file mode 100644
index 0000000..2d14f17
--- /dev/null
+++ b/arch/parisc/kernel/unwind.c
@@ -0,0 +1,483 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * 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/kernel.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/sort.h>
+
+#include <linux/uaccess.h>
+#include <asm/assembly.h>
+#include <asm/asm-offsets.h>
+#include <asm/ptrace.h>
+
+#include <asm/unwind.h>
+
+/* #define DEBUG 1 */
+#ifdef DEBUG
+#define dbg(x...) pr_debug(x)
+#else
+#define dbg(x...)
+#endif
+
+#define KERNEL_START (KERNEL_BINARY_TEXT_START)
+
+extern struct unwind_table_entry __start___unwind[];
+extern struct unwind_table_entry __stop___unwind[];
+
+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 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 {
+ unsigned long flags;
+
+ spin_lock_irqsave(&unwind_lock, flags);
+ 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) {
+ /* Move-to-front to exploit common traces */
+ list_move(&table->list, &unwind_tables);
+ break;
+ }
+ }
+ spin_unlock_irqrestore(&unwind_lock, flags);
+ }
+
+ 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) {
+ pr_warn("Out of order unwind entry! %px and %px\n",
+ start, start+1);
+ }
+
+ start->region_start += base_addr;
+ start->region_end += base_addr;
+ }
+}
+
+static int cmp_unwind_table_entry(const void *a, const void *b)
+{
+ return ((const struct unwind_table_entry *)a)->region_start
+ - ((const struct unwind_table_entry *)b)->region_start;
+}
+
+static void
+unwind_table_sort(struct unwind_table_entry *start,
+ struct unwind_table_entry *finish)
+{
+ sort(start, finish - start, sizeof(struct unwind_table_entry),
+ cmp_unwind_table_entry, NULL);
+}
+
+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 */
+int __init unwind_init(void)
+{
+ long start, stop;
+ register unsigned long gp __asm__ ("r27");
+
+ start = (long)&__start___unwind[0];
+ stop = (long)&__stop___unwind[0];
+
+ dbg("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 int unwind_special(struct unwind_frame_info *info, unsigned long pc, int frame_size)
+{
+ /*
+ * 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 handle_interruption;
+ 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 == (unsigned long) &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 == (unsigned long) &_switch_to_ret) {
+ info->prev_sp = info->sp - CALLEE_SAVE_FRAME_SIZE;
+ info->prev_ip = *(unsigned long *)(info->prev_sp - RP_OFFSET);
+ return 1;
+ }
+
+#ifdef CONFIG_IRQSTACKS
+ if (pc == (unsigned long) &_call_on_stack) {
+ 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;
+}
+
+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;
+
+ 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
+ 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;
+
+ /* The stack is at the end inside the thread_union
+ * struct. If we reach data, we have reached the
+ * beginning of the stack and should stop unwinding. */
+ if (info->prev_sp >= (unsigned long) task_thread_info(info->t) &&
+ info->prev_sp < ((unsigned long) task_thread_info(info->t)
+ + THREAD_SZ_ALGN)) {
+ info->prev_sp = 0;
+ break;
+ }
+
+ if (get_user(tmp, (unsigned long *)(info->prev_sp - RP_OFFSET)))
+ break;
+ info->prev_ip = tmp;
+ sp = info->prev_sp;
+ } while (!kernel_text_address(info->prev_ip));
+
+ 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 & 0xffffc001) == 0x37de0000 ||
+ (insn & 0xffe00001) == 0x6fc00000) {
+ /* ldo X(sp), sp, or stwm X,D(sp) */
+ 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 & 0xffe00009) == 0x73c00008) {
+ /* std,ma X,D(sp) */
+ frame_size += ((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);
+ }
+ }
+
+ 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)
+ 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 = kmalloc(sizeof(struct pt_regs), GFP_ATOMIC);
+ if (!r2)
+ return;
+ *r2 = *r;
+ r2->gr[30] = r->ksp;
+ r2->iaoq[0] = r->kpc;
+ unwind_frame_init(info, t, r2);
+ kfree(r2);
+}
+
+#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)
+{
+ 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)
+{
+ 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;
+}
+
+unsigned long return_address(unsigned int level)
+{
+ struct unwind_frame_info info;
+
+ /* initialize unwind info */
+ unwind_frame_init_task(&info, current, NULL);
+
+ /* unwind stack */
+ level += 2;
+ do {
+ if (unwind_once(&info) < 0 || info.ip == 0)
+ return 0;
+ if (!kernel_text_address(info.ip))
+ return 0;
+ } while (info.ip && level--);
+
+ return info.ip;
+}