arch: remove tile port

The Tile architecture port was added by Chris Metcalf in 2010, and
maintained until early 2018 when he orphaned it due to his departure
from Mellanox, and nobody else stepped up to maintain it. The product
line is still around in the form of the BlueField SoC, but no longer
uses the Tile architecture.

There are also still products for sale with Tile-GX SoCs, notably the
Mikrotik CCR router family. The products all use old (linux-3.3) kernels
with lots of patches and won't be upgraded by their manufacturers. There
have been efforts to port both OpenWRT and Debian to these, but both
projects have stalled and are very unlikely to be continued in the future.

Given that we are reasonably sure that nobody is still using the port
with an upstream kernel any more, it seems better to remove it now while
the port is in a good shape than to let it bitrot for a few years first.

Cc: Chris Metcalf <chris.d.metcalf@gmail.com>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Link: http://www.mellanox.com/page/npu_multicore_overview
Link: https://jenkins.debian.net/view/rebootstrap/job/rebootstrap_tilegx_gcc7/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 0 insertions, 539 deletions

diff --git a/arch/tile/kernel/stack.c b/arch/tile/kernel/stack.c
deleted file mode 100644
index 94ecbc6676e5..000000000000
--- a/arch/tile/kernel/stack.c
+++ /dev/null
@@ -1,539 +0,0 @@
-/*
- * 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/sched/debug.h>
-#include <linux/sched/task_stack.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 <linux/dcache.h>
-#include <linux/fs.h>
-#include <linux/hardirq.h>
-#include <linux/string.h>
-#include <asm/backtrace.h>
-#include <asm/page.h>
-#include <asm/ucontext.h>
-#include <asm/switch_to.h>
-#include <asm/sigframe.h>
-#include <asm/stack.h>
-#include <asm/vdso.h>
-#include <arch/abi.h>
-#include <arch/interrupts.h>
-
-#define KBT_ONGOING	0  /* Backtrace still ongoing */
-#define KBT_DONE	1  /* Backtrace cleanly completed */
-#define KBT_RUNNING	2  /* Can't run backtrace on a running task */
-#define KBT_LOOP	3  /* Backtrace entered a loop */
-
-/* Is address on the specified kernel stack? */
-static int in_kernel_stack(struct KBacktraceIterator *kbt, unsigned long 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;
-}
-
-/* Callback for backtracer; basically a glorified memcpy */
-static bool read_memory_func(void *result, unsigned long address,
-			     unsigned int size, void *vkbt)
-{
-	int retval;
-	struct KBacktraceIterator *kbt = (struct KBacktraceIterator *)vkbt;
-
-	if (address == 0)
-		return 0;
-	if (__kernel_text_address(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->is_current) {
-		return 0;	/* can't read from other user address spaces */
-	}
-	pagefault_disable();
-	retval = __copy_from_user_inatomic(result,
-					   (void __user __force *)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)
-{
-	char fault[64];
-	unsigned long sp = kbt->it.sp;
-	struct pt_regs *p;
-
-	if (sp % sizeof(long) != 0)
-		return NULL;
-	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 (kbt->verbose) {     /* else we aren't going to use it */
-		if (p->faultnum == INT_SWINT_1 ||
-		    p->faultnum == INT_SWINT_1_SIGRETURN)
-			snprintf(fault, sizeof(fault),
-				 "syscall %ld", p->regs[TREG_SYSCALL_NR]);
-		else
-			snprintf(fault, sizeof(fault),
-				 "interrupt %ld", p->faultnum);
-	}
-	if (EX1_PL(p->ex1) == KERNEL_PL &&
-	    __kernel_text_address(p->pc) &&
-	    in_kernel_stack(kbt, p->sp) &&
-	    p->sp >= sp) {
-		if (kbt->verbose)
-			pr_err("  <%s while in kernel mode>\n", fault);
-	} else if (user_mode(p) &&
-		   p->sp < PAGE_OFFSET && p->sp != 0) {
-		if (kbt->verbose)
-			pr_err("  <%s while in user mode>\n", fault);
-	} else {
-		if (kbt->verbose && (p->pc != 0 || p->sp != 0 || p->ex1 != 0))
-			pr_err("  (odd fault: pc %#lx, sp %#lx, ex1 %#lx?)\n",
-			       p->pc, p->sp, p->ex1);
-		return NULL;
-	}
-	if (kbt->profile && ((1ULL << p->faultnum) & QUEUED_INTERRUPTS) != 0)
-		return NULL;
-	return p;
-}
-
-/* Is the iterator pointing to a sigreturn trampoline? */
-static int is_sigreturn(struct KBacktraceIterator *kbt)
-{
-	return kbt->task->mm &&
-		(kbt->it.pc == ((ulong)kbt->task->mm->context.vdso_base +
-				(ulong)&__vdso_rt_sigreturn));
-}
-
-/* Return a pt_regs pointer for a valid signal handler frame */
-static struct pt_regs *valid_sigframe(struct KBacktraceIterator* kbt,
-				      struct rt_sigframe* kframe)
-{
-	BacktraceIterator *b = &kbt->it;
-
-	if (is_sigreturn(kbt) && b->sp < PAGE_OFFSET &&
-	    b->sp % sizeof(long) == 0) {
-		int retval;
-		pagefault_disable();
-		retval = __copy_from_user_inatomic(
-			kframe, (void __user __force *)b->sp,
-			sizeof(*kframe));
-		pagefault_enable();
-		if (retval != 0 ||
-		    (unsigned int)(kframe->info.si_signo) >= _NSIG)
-			return NULL;
-		if (kbt->verbose) {
-			pr_err("  <received signal %d>\n",
-			       kframe->info.si_signo);
-		}
-		return (struct pt_regs *)&kframe->uc.uc_mcontext;
-	}
-	return NULL;
-}
-
-static int KBacktraceIterator_restart(struct KBacktraceIterator *kbt)
-{
-	struct pt_regs *p;
-	struct rt_sigframe kframe;
-
-	p = valid_fault_handler(kbt);
-	if (p == NULL)
-		p = valid_sigframe(kbt, &kframe);
-	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 (!is_sigreturn(kbt))
-				return KBT_ONGOING;
-		} while (backtrace_next(&kbt->it));
-
-		if (!KBacktraceIterator_restart(kbt))
-			return KBT_DONE;
-	}
-}
-
-/*
- * 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 = raw_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) {
-		pr_err("WARNING: cpu %d: kernel stack %#lx..%#lx underrun!\n"
-		       "  sp %#lx (%#lx in caller), caller pc %#lx, lr %#lx\n",
-		       cpu, ksp0_base, ksp0, sp, regs->sp, regs->pc, regs->lr);
-	}
-
-	else if (sp < ksp0_base + sizeof(struct thread_info)) {
-		pr_err("WARNING: cpu %d: kernel stack %#lx..%#lx overrun!\n"
-		       "  sp %#lx (%#lx in caller), caller pc %#lx, lr %#lx\n",
-		       cpu, ksp0_base, ksp0, sp, regs->sp, regs->pc, regs->lr);
-	}
-}
-
-void KBacktraceIterator_init(struct KBacktraceIterator *kbt,
-			     struct task_struct *t, struct pt_regs *regs)
-{
-	unsigned long 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.
-	 */
-	is_current = (t == NULL || t == current);
-	kbt->is_current = is_current;
-	if (is_current)
-		t = validate_current();
-	kbt->task = t;
-	kbt->verbose = 0;   /* override in caller if desired */
-	kbt->profile = 0;   /* override in caller if desired */
-	kbt->end = KBT_ONGOING;
-	kbt->new_context = 1;
-	if (is_current)
-		validate_stack(regs);
-
-	if (regs == NULL) {
-		if (is_current || t->state == TASK_RUNNING) {
-			/* Can't do this; we need registers */
-			kbt->end = KBT_RUNNING;
-			return;
-		}
-		pc = 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 != KBT_ONGOING;
-}
-EXPORT_SYMBOL(KBacktraceIterator_end);
-
-void KBacktraceIterator_next(struct KBacktraceIterator *kbt)
-{
-	unsigned long old_pc = kbt->it.pc, old_sp = kbt->it.sp;
-	kbt->new_context = 0;
-	if (!backtrace_next(&kbt->it) && !KBacktraceIterator_restart(kbt)) {
-		kbt->end = KBT_DONE;
-		return;
-	}
-	kbt->end = KBacktraceIterator_next_item_inclusive(kbt);
-	if (old_pc == kbt->it.pc && old_sp == kbt->it.sp) {
-		/* Trapped in a loop; give up. */
-		kbt->end = KBT_LOOP;
-	}
-}
-EXPORT_SYMBOL(KBacktraceIterator_next);
-
-static void describe_addr(struct KBacktraceIterator *kbt,
-			  unsigned long address,
-			  int have_mmap_sem, char *buf, size_t bufsize)
-{
-	struct vm_area_struct *vma;
-	size_t namelen, remaining;
-	unsigned long size, offset, adjust;
-	char *p, *modname;
-	const char *name;
-	int rc;
-
-	/*
-	 * Look one byte back for every caller frame (i.e. those that
-	 * aren't a new context) so we look up symbol data for the
-	 * call itself, not the following instruction, which may be on
-	 * a different line (or in a different function).
-	 */
-	adjust = !kbt->new_context;
-	address -= adjust;
-
-	if (address >= PAGE_OFFSET) {
-		/* Handle kernel symbols. */
-		BUG_ON(bufsize < KSYM_NAME_LEN);
-		name = kallsyms_lookup(address, &size, &offset,
-				       &modname, buf);
-		if (name == NULL) {
-			buf[0] = '\0';
-			return;
-		}
-		namelen = strlen(buf);
-		remaining = (bufsize - 1) - namelen;
-		p = buf + namelen;
-		rc = snprintf(p, remaining, "+%#lx/%#lx ",
-			      offset + adjust, size);
-		if (modname && rc < remaining)
-			snprintf(p + rc, remaining - rc, "[%s] ", modname);
-		buf[bufsize-1] = '\0';
-		return;
-	}
-
-	/* If we don't have the mmap_sem, we can't show any more info. */
-	buf[0] = '\0';
-	if (!have_mmap_sem)
-		return;
-
-	/* Find vma info. */
-	vma = find_vma(kbt->task->mm, address);
-	if (vma == NULL || address < vma->vm_start) {
-		snprintf(buf, bufsize, "[unmapped address] ");
-		return;
-	}
-
-	if (vma->vm_file) {
-		p = file_path(vma->vm_file, buf, bufsize);
-		if (IS_ERR(p))
-			p = "?";
-		name = kbasename(p);
-	} else {
-		name = "anon";
-	}
-
-	/* Generate a string description of the vma info. */
-	namelen = strlen(name);
-	remaining = (bufsize - 1) - namelen;
-	memmove(buf, name, namelen);
-	snprintf(buf + namelen, remaining, "[%lx+%lx] ",
-		 vma->vm_start, vma->vm_end - vma->vm_start);
-}
-
-/*
- * Avoid possible crash recursion during backtrace.  If it happens, it
- * makes it easy to lose the actual root cause of the failure, so we
- * put a simple guard on all the backtrace loops.
- */
-static bool start_backtrace(void)
-{
-	if (current_thread_info()->in_backtrace) {
-		pr_err("Backtrace requested while in backtrace!\n");
-		return false;
-	}
-	current_thread_info()->in_backtrace = true;
-	return true;
-}
-
-static void end_backtrace(void)
-{
-	current_thread_info()->in_backtrace = false;
-}
-
-/*
- * This method wraps the backtracer's more generic support.
- * It is only invoked from the architecture-specific code; show_stack()
- * and dump_stack() are architecture-independent entry points.
- */
-void tile_show_stack(struct KBacktraceIterator *kbt)
-{
-	int i;
-	int have_mmap_sem = 0;
-
-	if (!start_backtrace())
-		return;
-	kbt->verbose = 1;
-	i = 0;
-	for (; !KBacktraceIterator_end(kbt); KBacktraceIterator_next(kbt)) {
-		char namebuf[KSYM_NAME_LEN+100];
-		unsigned long address = kbt->it.pc;
-
-		/*
-		 * Try to acquire the mmap_sem as we pass into userspace.
-		 * If we're in an interrupt context, don't even try, since
-		 * it's not safe to call e.g. d_path() from an interrupt,
-		 * since it uses spin locks without disabling interrupts.
-		 * Note we test "kbt->task == current", not "kbt->is_current",
-		 * since we're checking that "current" will work in d_path().
-		 */
-		if (kbt->task == current && address < PAGE_OFFSET &&
-		    !have_mmap_sem && kbt->task->mm && !in_interrupt()) {
-			have_mmap_sem =
-				down_read_trylock(&kbt->task->mm->mmap_sem);
-		}
-
-		describe_addr(kbt, address, have_mmap_sem,
-			      namebuf, sizeof(namebuf));
-
-		pr_err("  frame %d: 0x%lx %s(sp 0x%lx)\n",
-		       i++, address, namebuf, (unsigned long)(kbt->it.sp));
-
-		if (i >= 100) {
-			pr_err("Stack dump truncated (%d frames)\n", i);
-			break;
-		}
-	}
-	if (kbt->end == KBT_LOOP)
-		pr_err("Stack dump stopped; next frame identical to this one\n");
-	if (have_mmap_sem)
-		up_read(&kbt->task->mm->mmap_sem);
-	end_backtrace();
-}
-EXPORT_SYMBOL(tile_show_stack);
-
-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;
-}
-
-/* Deprecated function currently only used by kernel_double_fault(). */
-void _dump_stack(int dummy, ulong pc, ulong lr, ulong sp, ulong r52)
-{
-	struct KBacktraceIterator kbt;
-	struct pt_regs regs;
-
-	regs_to_pt_regs(&regs, pc, lr, sp, r52);
-	KBacktraceIterator_init(&kbt, NULL, &regs);
-	tile_show_stack(&kbt);
-}
-
-/* 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));
-}
-
-/*
- * Called from sched_show_task() with task != NULL, or dump_stack()
- * with task == NULL.  The esp argument is always NULL.
- */
-void show_stack(struct task_struct *task, unsigned long *esp)
-{
-	struct KBacktraceIterator kbt;
-	if (task == NULL || task == current) {
-		KBacktraceIterator_init_current(&kbt);
-		KBacktraceIterator_next(&kbt);  /* don't show first frame */
-	} else {
-		KBacktraceIterator_init(&kbt, task, NULL);
-	}
-	tile_show_stack(&kbt);
-}
-
-#ifdef CONFIG_STACKTRACE
-
-/* Support generic Linux stack API too */
-
-static void save_stack_trace_common(struct task_struct *task,
-				    struct pt_regs *regs,
-				    bool user,
-				    struct stack_trace *trace)
-{
-	struct KBacktraceIterator kbt;
-	int skip = trace->skip;
-	int i = 0;
-
-	if (!start_backtrace())
-		goto done;
-	if (regs != NULL) {
-		KBacktraceIterator_init(&kbt, NULL, regs);
-	} else if (task == NULL || task == current) {
-		KBacktraceIterator_init_current(&kbt);
-		skip++;  /* don't show KBacktraceIterator_init_current */
-	} else {
-		KBacktraceIterator_init(&kbt, task, NULL);
-	}
-	for (; !KBacktraceIterator_end(&kbt); KBacktraceIterator_next(&kbt)) {
-		if (skip) {
-			--skip;
-			continue;
-		}
-		if (i >= trace->max_entries ||
-		    (!user && kbt.it.pc < PAGE_OFFSET))
-			break;
-		trace->entries[i++] = kbt.it.pc;
-	}
-	end_backtrace();
-done:
-	if (i < trace->max_entries)
-		trace->entries[i++] = ULONG_MAX;
-	trace->nr_entries = i;
-}
-
-void save_stack_trace_tsk(struct task_struct *task, struct stack_trace *trace)
-{
-	save_stack_trace_common(task, NULL, false, trace);
-}
-EXPORT_SYMBOL(save_stack_trace_tsk);
-
-void save_stack_trace(struct stack_trace *trace)
-{
-	save_stack_trace_common(NULL, NULL, false, trace);
-}
-EXPORT_SYMBOL_GPL(save_stack_trace);
-
-void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
-{
-	save_stack_trace_common(NULL, regs, false, trace);
-}
-
-void save_stack_trace_user(struct stack_trace *trace)
-{
-	/* Trace user stack if we are not a kernel thread. */
-	if (current->mm)
-		save_stack_trace_common(NULL, task_pt_regs(current),
-					true, trace);
-	else if (trace->nr_entries < trace->max_entries)
-		trace->entries[trace->nr_entries++] = ULONG_MAX;
-}
-#endif
-
-/* In entry.S */
-EXPORT_SYMBOL(KBacktraceIterator_init_current);