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-rw-r--r--arch/tile/kernel/stack.c485
1 files changed, 485 insertions, 0 deletions
diff --git a/arch/tile/kernel/stack.c b/arch/tile/kernel/stack.c
new file mode 100644
index 000000000000..382170b4b40a
--- /dev/null
+++ b/arch/tile/kernel/stack.c
@@ -0,0 +1,485 @@
+/*
+ * Copyright 2010 Tilera Corporation. All Rights Reserved.
+ *
+ *   This program is free software; you can redistribute it and/or
+ *   modify it under the terms of the GNU General Public License
+ *   as published by the Free Software Foundation, version 2.
+ *
+ *   This program is distributed in the hope that it will be useful, but
+ *   WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ *   NON INFRINGEMENT.  See the GNU General Public License for
+ *   more details.
+ */
+
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/kprobes.h>
+#include <linux/module.h>
+#include <linux/pfn.h>
+#include <linux/kallsyms.h>
+#include <linux/stacktrace.h>
+#include <linux/uaccess.h>
+#include <linux/mmzone.h>
+#include <asm/backtrace.h>
+#include <asm/page.h>
+#include <asm/tlbflush.h>
+#include <asm/ucontext.h>
+#include <asm/sigframe.h>
+#include <asm/stack.h>
+#include <arch/abi.h>
+#include <arch/interrupts.h>
+
+
+/* Is address on the specified kernel stack? */
+static int in_kernel_stack(struct KBacktraceIterator *kbt, VirtualAddress sp)
+{
+	ulong kstack_base = (ulong) kbt->task->stack;
+	if (kstack_base == 0)  /* corrupt task pointer; just follow stack... */
+		return sp >= PAGE_OFFSET && sp < (unsigned long)high_memory;
+	return sp >= kstack_base && sp < kstack_base + THREAD_SIZE;
+}
+
+/* Is address in the specified kernel code? */
+static int in_kernel_text(VirtualAddress address)
+{
+	return (address >= MEM_SV_INTRPT &&
+		address < MEM_SV_INTRPT + HPAGE_SIZE);
+}
+
+/* Is address valid for reading? */
+static int valid_address(struct KBacktraceIterator *kbt, VirtualAddress address)
+{
+	HV_PTE *l1_pgtable = kbt->pgtable;
+	HV_PTE *l2_pgtable;
+	unsigned long pfn;
+	HV_PTE pte;
+	struct page *page;
+
+	pte = l1_pgtable[HV_L1_INDEX(address)];
+	if (!hv_pte_get_present(pte))
+		return 0;
+	pfn = hv_pte_get_pfn(pte);
+	if (pte_huge(pte)) {
+		if (!pfn_valid(pfn)) {
+			printk(KERN_ERR "huge page has bad pfn %#lx\n", pfn);
+			return 0;
+		}
+		return hv_pte_get_present(pte) && hv_pte_get_readable(pte);
+	}
+
+	page = pfn_to_page(pfn);
+	if (PageHighMem(page)) {
+		printk(KERN_ERR "L2 page table not in LOWMEM (%#llx)\n",
+		       HV_PFN_TO_CPA(pfn));
+		return 0;
+	}
+	l2_pgtable = (HV_PTE *)pfn_to_kaddr(pfn);
+	pte = l2_pgtable[HV_L2_INDEX(address)];
+	return hv_pte_get_present(pte) && hv_pte_get_readable(pte);
+}
+
+/* Callback for backtracer; basically a glorified memcpy */
+static bool read_memory_func(void *result, VirtualAddress address,
+			     unsigned int size, void *vkbt)
+{
+	int retval;
+	struct KBacktraceIterator *kbt = (struct KBacktraceIterator *)vkbt;
+	if (in_kernel_text(address)) {
+		/* OK to read kernel code. */
+	} else if (address >= PAGE_OFFSET) {
+		/* We only tolerate kernel-space reads of this task's stack */
+		if (!in_kernel_stack(kbt, address))
+			return 0;
+	} else if (kbt->pgtable == NULL) {
+		return 0;	/* can't read user space in other tasks */
+	} else if (!valid_address(kbt, address)) {
+		return 0;	/* invalid user-space address */
+	}
+	pagefault_disable();
+	retval = __copy_from_user_inatomic(result, (const void *)address,
+					   size);
+	pagefault_enable();
+	return (retval == 0);
+}
+
+/* Return a pt_regs pointer for a valid fault handler frame */
+static struct pt_regs *valid_fault_handler(struct KBacktraceIterator* kbt)
+{
+#ifndef __tilegx__
+	const char *fault = NULL;  /* happy compiler */
+	char fault_buf[64];
+	VirtualAddress sp = kbt->it.sp;
+	struct pt_regs *p;
+
+	if (!in_kernel_stack(kbt, sp))
+		return NULL;
+	if (!in_kernel_stack(kbt, sp + C_ABI_SAVE_AREA_SIZE + PTREGS_SIZE-1))
+		return NULL;
+	p = (struct pt_regs *)(sp + C_ABI_SAVE_AREA_SIZE);
+	if (p->faultnum == INT_SWINT_1 || p->faultnum == INT_SWINT_1_SIGRETURN)
+		fault = "syscall";
+	else {
+		if (kbt->verbose) {     /* else we aren't going to use it */
+			snprintf(fault_buf, sizeof(fault_buf),
+				 "interrupt %ld", p->faultnum);
+			fault = fault_buf;
+		}
+	}
+	if (EX1_PL(p->ex1) == KERNEL_PL &&
+	    in_kernel_text(p->pc) &&
+	    in_kernel_stack(kbt, p->sp) &&
+	    p->sp >= sp) {
+		if (kbt->verbose)
+			printk(KERN_ERR "  <%s while in kernel mode>\n", fault);
+	} else if (EX1_PL(p->ex1) == USER_PL &&
+	    p->pc < PAGE_OFFSET &&
+	    p->sp < PAGE_OFFSET) {
+		if (kbt->verbose)
+			printk(KERN_ERR "  <%s while in user mode>\n", fault);
+	} else if (kbt->verbose) {
+		printk(KERN_ERR "  (odd fault: pc %#lx, sp %#lx, ex1 %#lx?)\n",
+		       p->pc, p->sp, p->ex1);
+		p = NULL;
+	}
+	if (!kbt->profile || (INT_MASK(p->faultnum) & QUEUED_INTERRUPTS) == 0)
+		return p;
+#endif
+	return NULL;
+}
+
+/* Is the pc pointing to a sigreturn trampoline? */
+static int is_sigreturn(VirtualAddress pc)
+{
+	return (pc == VDSO_BASE);
+}
+
+/* Return a pt_regs pointer for a valid signal handler frame */
+static struct pt_regs *valid_sigframe(struct KBacktraceIterator* kbt)
+{
+	BacktraceIterator *b = &kbt->it;
+
+	if (b->pc == VDSO_BASE) {
+		struct rt_sigframe *frame;
+		unsigned long sigframe_top =
+			b->sp + sizeof(struct rt_sigframe) - 1;
+		if (!valid_address(kbt, b->sp) ||
+		    !valid_address(kbt, sigframe_top)) {
+			if (kbt->verbose)
+				printk("  (odd signal: sp %#lx?)\n",
+				       (unsigned long)(b->sp));
+			return NULL;
+		}
+		frame = (struct rt_sigframe *)b->sp;
+		if (kbt->verbose) {
+			printk(KERN_ERR "  <received signal %d>\n",
+			       frame->info.si_signo);
+		}
+		return &frame->uc.uc_mcontext.regs;
+	}
+	return NULL;
+}
+
+int KBacktraceIterator_is_sigreturn(struct KBacktraceIterator *kbt)
+{
+	return is_sigreturn(kbt->it.pc);
+}
+
+static int KBacktraceIterator_restart(struct KBacktraceIterator *kbt)
+{
+	struct pt_regs *p;
+
+	p = valid_fault_handler(kbt);
+	if (p == NULL)
+		p = valid_sigframe(kbt);
+	if (p == NULL)
+		return 0;
+	backtrace_init(&kbt->it, read_memory_func, kbt,
+		       p->pc, p->lr, p->sp, p->regs[52]);
+	kbt->new_context = 1;
+	return 1;
+}
+
+/* Find a frame that isn't a sigreturn, if there is one. */
+static int KBacktraceIterator_next_item_inclusive(
+	struct KBacktraceIterator *kbt)
+{
+	for (;;) {
+		do {
+			if (!KBacktraceIterator_is_sigreturn(kbt))
+				return 1;
+		} while (backtrace_next(&kbt->it));
+
+		if (!KBacktraceIterator_restart(kbt))
+			return 0;
+	}
+}
+
+/*
+ * If the current sp is on a page different than what we recorded
+ * as the top-of-kernel-stack last time we context switched, we have
+ * probably blown the stack, and nothing is going to work out well.
+ * If we can at least get out a warning, that may help the debug,
+ * though we probably won't be able to backtrace into the code that
+ * actually did the recursive damage.
+ */
+static void validate_stack(struct pt_regs *regs)
+{
+	int cpu = smp_processor_id();
+	unsigned long ksp0 = get_current_ksp0();
+	unsigned long ksp0_base = ksp0 - THREAD_SIZE;
+	unsigned long sp = stack_pointer;
+
+	if (EX1_PL(regs->ex1) == KERNEL_PL && regs->sp >= ksp0) {
+		printk("WARNING: cpu %d: kernel stack page %#lx underrun!\n"
+		       "  sp %#lx (%#lx in caller), caller pc %#lx, lr %#lx\n",
+		       cpu, ksp0_base, sp, regs->sp, regs->pc, regs->lr);
+	}
+
+	else if (sp < ksp0_base + sizeof(struct thread_info)) {
+		printk("WARNING: cpu %d: kernel stack page %#lx overrun!\n"
+		       "  sp %#lx (%#lx in caller), caller pc %#lx, lr %#lx\n",
+		       cpu, ksp0_base, sp, regs->sp, regs->pc, regs->lr);
+	}
+}
+
+void KBacktraceIterator_init(struct KBacktraceIterator *kbt,
+			     struct task_struct *t, struct pt_regs *regs)
+{
+	VirtualAddress pc, lr, sp, r52;
+	int is_current;
+
+	/*
+	 * Set up callback information.  We grab the kernel stack base
+	 * so we will allow reads of that address range, and if we're
+	 * asking about the current process we grab the page table
+	 * so we can check user accesses before trying to read them.
+	 * We flush the TLB to avoid any weird skew issues.
+	 */
+	is_current = (t == NULL);
+	kbt->is_current = is_current;
+	if (is_current)
+		t = validate_current();
+	kbt->task = t;
+	kbt->pgtable = NULL;
+	kbt->verbose = 0;   /* override in caller if desired */
+	kbt->profile = 0;   /* override in caller if desired */
+	kbt->end = 0;
+	kbt->new_context = 0;
+	if (is_current) {
+		HV_PhysAddr pgdir_pa = hv_inquire_context().page_table;
+		if (pgdir_pa == (unsigned long)swapper_pg_dir - PAGE_OFFSET) {
+			/*
+			 * Not just an optimization: this also allows
+			 * this to work at all before va/pa mappings
+			 * are set up.
+			 */
+			kbt->pgtable = swapper_pg_dir;
+		} else {
+			struct page *page = pfn_to_page(PFN_DOWN(pgdir_pa));
+			if (!PageHighMem(page))
+				kbt->pgtable = __va(pgdir_pa);
+			else
+				printk(KERN_ERR "page table not in LOWMEM"
+				       " (%#llx)\n", pgdir_pa);
+		}
+		local_flush_tlb_all();
+		validate_stack(regs);
+	}
+
+	if (regs == NULL) {
+		extern const void *get_switch_to_pc(void);
+		if (is_current || t->state == TASK_RUNNING) {
+			/* Can't do this; we need registers */
+			kbt->end = 1;
+			return;
+		}
+		pc = (ulong) get_switch_to_pc();
+		lr = t->thread.pc;
+		sp = t->thread.ksp;
+		r52 = 0;
+	} else {
+		pc = regs->pc;
+		lr = regs->lr;
+		sp = regs->sp;
+		r52 = regs->regs[52];
+	}
+
+	backtrace_init(&kbt->it, read_memory_func, kbt, pc, lr, sp, r52);
+	kbt->end = !KBacktraceIterator_next_item_inclusive(kbt);
+}
+EXPORT_SYMBOL(KBacktraceIterator_init);
+
+int KBacktraceIterator_end(struct KBacktraceIterator *kbt)
+{
+	return kbt->end;
+}
+EXPORT_SYMBOL(KBacktraceIterator_end);
+
+void KBacktraceIterator_next(struct KBacktraceIterator *kbt)
+{
+	kbt->new_context = 0;
+	if (!backtrace_next(&kbt->it) &&
+	    !KBacktraceIterator_restart(kbt)) {
+			kbt->end = 1;
+			return;
+		}
+
+	kbt->end = !KBacktraceIterator_next_item_inclusive(kbt);
+}
+EXPORT_SYMBOL(KBacktraceIterator_next);
+
+/*
+ * This method wraps the backtracer's more generic support.
+ * It is only invoked from the architecture-specific code; show_stack()
+ * and dump_stack() (in entry.S) are architecture-independent entry points.
+ */
+void tile_show_stack(struct KBacktraceIterator *kbt, int headers)
+{
+	int i;
+
+	if (headers) {
+		/*
+		 * Add a blank line since if we are called from panic(),
+		 * then bust_spinlocks() spit out a space in front of us
+		 * and it will mess up our KERN_ERR.
+		 */
+		printk("\n");
+		printk(KERN_ERR "Starting stack dump of tid %d, pid %d (%s)"
+		       " on cpu %d at cycle %lld\n",
+		       kbt->task->pid, kbt->task->tgid, kbt->task->comm,
+		       smp_processor_id(), get_cycles());
+	}
+#ifdef __tilegx__
+	if (kbt->is_current) {
+		__insn_mtspr(SPR_SIM_CONTROL,
+			     SIM_DUMP_SPR_ARG(SIM_DUMP_BACKTRACE));
+	}
+#endif
+	kbt->verbose = 1;
+	i = 0;
+	for (; !KBacktraceIterator_end(kbt); KBacktraceIterator_next(kbt)) {
+		char *modname;
+		const char *name;
+		unsigned long address = kbt->it.pc;
+		unsigned long offset, size;
+		char namebuf[KSYM_NAME_LEN+100];
+
+		if (address >= PAGE_OFFSET)
+			name = kallsyms_lookup(address, &size, &offset,
+					       &modname, namebuf);
+		else
+			name = NULL;
+
+		if (!name)
+			namebuf[0] = '\0';
+		else {
+			size_t namelen = strlen(namebuf);
+			size_t remaining = (sizeof(namebuf) - 1) - namelen;
+			char *p = namebuf + namelen;
+			int rc = snprintf(p, remaining, "+%#lx/%#lx ",
+					  offset, size);
+			if (modname && rc < remaining)
+				snprintf(p + rc, remaining - rc,
+					 "[%s] ", modname);
+			namebuf[sizeof(namebuf)-1] = '\0';
+		}
+
+		printk(KERN_ERR "  frame %d: 0x%lx %s(sp 0x%lx)\n",
+		       i++, address, namebuf, (unsigned long)(kbt->it.sp));
+
+		if (i >= 100) {
+			printk(KERN_ERR "Stack dump truncated"
+			       " (%d frames)\n", i);
+			break;
+		}
+	}
+	if (headers)
+		printk(KERN_ERR "Stack dump complete\n");
+}
+EXPORT_SYMBOL(tile_show_stack);
+
+
+/* This is called from show_regs() and _dump_stack() */
+void dump_stack_regs(struct pt_regs *regs)
+{
+	struct KBacktraceIterator kbt;
+	KBacktraceIterator_init(&kbt, NULL, regs);
+	tile_show_stack(&kbt, 1);
+}
+EXPORT_SYMBOL(dump_stack_regs);
+
+static struct pt_regs *regs_to_pt_regs(struct pt_regs *regs,
+				       ulong pc, ulong lr, ulong sp, ulong r52)
+{
+	memset(regs, 0, sizeof(struct pt_regs));
+	regs->pc = pc;
+	regs->lr = lr;
+	regs->sp = sp;
+	regs->regs[52] = r52;
+	return regs;
+}
+
+/* This is called from dump_stack() and just converts to pt_regs */
+void _dump_stack(int dummy, ulong pc, ulong lr, ulong sp, ulong r52)
+{
+	struct pt_regs regs;
+	dump_stack_regs(regs_to_pt_regs(&regs, pc, lr, sp, r52));
+}
+
+/* This is called from KBacktraceIterator_init_current() */
+void _KBacktraceIterator_init_current(struct KBacktraceIterator *kbt, ulong pc,
+				      ulong lr, ulong sp, ulong r52)
+{
+	struct pt_regs regs;
+	KBacktraceIterator_init(kbt, NULL,
+				regs_to_pt_regs(&regs, pc, lr, sp, r52));
+}
+
+/* This is called only from kernel/sched.c, with esp == NULL */
+void show_stack(struct task_struct *task, unsigned long *esp)
+{
+	struct KBacktraceIterator kbt;
+	if (task == NULL || task == current)
+		KBacktraceIterator_init_current(&kbt);
+	else
+		KBacktraceIterator_init(&kbt, task, NULL);
+	tile_show_stack(&kbt, 0);
+}
+
+#ifdef CONFIG_STACKTRACE
+
+/* Support generic Linux stack API too */
+
+void save_stack_trace_tsk(struct task_struct *task, struct stack_trace *trace)
+{
+	struct KBacktraceIterator kbt;
+	int skip = trace->skip;
+	int i = 0;
+
+	if (task == NULL || task == current)
+		KBacktraceIterator_init_current(&kbt);
+	else
+		KBacktraceIterator_init(&kbt, task, NULL);
+	for (; !KBacktraceIterator_end(&kbt); KBacktraceIterator_next(&kbt)) {
+		if (skip) {
+			--skip;
+			continue;
+		}
+		if (i >= trace->max_entries || kbt.it.pc < PAGE_OFFSET)
+			break;
+		trace->entries[i++] = kbt.it.pc;
+	}
+	trace->nr_entries = i;
+}
+EXPORT_SYMBOL(save_stack_trace_tsk);
+
+void save_stack_trace(struct stack_trace *trace)
+{
+	save_stack_trace_tsk(NULL, trace);
+}
+
+#endif
+
+/* In entry.S */
+EXPORT_SYMBOL(KBacktraceIterator_init_current);
generated by cgit-pink 1.4.1 (git 2.36.1) at 2024-10-07 20:36:28 +0000