1 files changed, 379 insertions, 0 deletions

diff --git a/arch/sparc/mm/fault_32.c b/arch/sparc/mm/fault_32.c
new file mode 100644
index 000000000..56eb40d38
--- /dev/null
+++ b/arch/sparc/mm/fault_32.c
@@ -0,0 +1,379 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * fault.c:  Page fault handlers for the Sparc.
+ *
+ * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
+ * Copyright (C) 1996 Eddie C. Dost (ecd@skynet.be)
+ * Copyright (C) 1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
+ */
+
+#include <asm/head.h>
+
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/sched.h>
+#include <linux/ptrace.h>
+#include <linux/mman.h>
+#include <linux/threads.h>
+#include <linux/kernel.h>
+#include <linux/signal.h>
+#include <linux/mm.h>
+#include <linux/smp.h>
+#include <linux/perf_event.h>
+#include <linux/interrupt.h>
+#include <linux/kdebug.h>
+#include <linux/uaccess.h>
+#include <linux/extable.h>
+
+#include <asm/page.h>
+#include <asm/openprom.h>
+#include <asm/oplib.h>
+#include <asm/setup.h>
+#include <asm/smp.h>
+#include <asm/traps.h>
+
+#include "mm_32.h"
+
+int show_unhandled_signals = 1;
+
+static void __noreturn unhandled_fault(unsigned long address,
+				       struct task_struct *tsk,
+				       struct pt_regs *regs)
+{
+	if ((unsigned long) address < PAGE_SIZE) {
+		printk(KERN_ALERT
+		    "Unable to handle kernel NULL pointer dereference\n");
+	} else {
+		printk(KERN_ALERT "Unable to handle kernel paging request at virtual address %08lx\n",
+		       address);
+	}
+	printk(KERN_ALERT "tsk->{mm,active_mm}->context = %08lx\n",
+		(tsk->mm ? tsk->mm->context : tsk->active_mm->context));
+	printk(KERN_ALERT "tsk->{mm,active_mm}->pgd = %08lx\n",
+		(tsk->mm ? (unsigned long) tsk->mm->pgd :
+			(unsigned long) tsk->active_mm->pgd));
+	die_if_kernel("Oops", regs);
+}
+
+static inline void
+show_signal_msg(struct pt_regs *regs, int sig, int code,
+		unsigned long address, struct task_struct *tsk)
+{
+	if (!unhandled_signal(tsk, sig))
+		return;
+
+	if (!printk_ratelimit())
+		return;
+
+	printk("%s%s[%d]: segfault at %lx ip %px (rpc %px) sp %px error %x",
+	       task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
+	       tsk->comm, task_pid_nr(tsk), address,
+	       (void *)regs->pc, (void *)regs->u_regs[UREG_I7],
+	       (void *)regs->u_regs[UREG_FP], code);
+
+	print_vma_addr(KERN_CONT " in ", regs->pc);
+
+	printk(KERN_CONT "\n");
+}
+
+static void __do_fault_siginfo(int code, int sig, struct pt_regs *regs,
+			       unsigned long addr)
+{
+	if (unlikely(show_unhandled_signals))
+		show_signal_msg(regs, sig, code,
+				addr, current);
+
+	force_sig_fault(sig, code, (void __user *) addr);
+}
+
+static unsigned long compute_si_addr(struct pt_regs *regs, int text_fault)
+{
+	unsigned int insn;
+
+	if (text_fault)
+		return regs->pc;
+
+	if (regs->psr & PSR_PS)
+		insn = *(unsigned int *) regs->pc;
+	else
+		__get_user(insn, (unsigned int *) regs->pc);
+
+	return safe_compute_effective_address(regs, insn);
+}
+
+static noinline void do_fault_siginfo(int code, int sig, struct pt_regs *regs,
+				      int text_fault)
+{
+	unsigned long addr = compute_si_addr(regs, text_fault);
+
+	__do_fault_siginfo(code, sig, regs, addr);
+}
+
+asmlinkage void do_sparc_fault(struct pt_regs *regs, int text_fault, int write,
+			       unsigned long address)
+{
+	struct vm_area_struct *vma;
+	struct task_struct *tsk = current;
+	struct mm_struct *mm = tsk->mm;
+	int from_user = !(regs->psr & PSR_PS);
+	int code;
+	vm_fault_t fault;
+	unsigned int flags = FAULT_FLAG_DEFAULT;
+
+	if (text_fault)
+		address = regs->pc;
+
+	/*
+	 * We fault-in kernel-space virtual memory on-demand. The
+	 * 'reference' page table is init_mm.pgd.
+	 *
+	 * NOTE! We MUST NOT take any locks for this case. We may
+	 * be in an interrupt or a critical region, and should
+	 * only copy the information from the master page table,
+	 * nothing more.
+	 */
+	code = SEGV_MAPERR;
+	if (address >= TASK_SIZE)
+		goto vmalloc_fault;
+
+	/*
+	 * If we're in an interrupt or have no user
+	 * context, we must not take the fault..
+	 */
+	if (pagefault_disabled() || !mm)
+		goto no_context;
+
+	if (!from_user && address >= PAGE_OFFSET)
+		goto no_context;
+
+	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
+
+retry:
+	vma = lock_mm_and_find_vma(mm, address, regs);
+	if (!vma)
+		goto bad_area_nosemaphore;
+	/*
+	 * Ok, we have a good vm_area for this memory access, so
+	 * we can handle it..
+	 */
+	code = SEGV_ACCERR;
+	if (write) {
+		if (!(vma->vm_flags & VM_WRITE))
+			goto bad_area;
+	} else {
+		/* Allow reads even for write-only mappings */
+		if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
+			goto bad_area;
+	}
+
+	if (from_user)
+		flags |= FAULT_FLAG_USER;
+	if (write)
+		flags |= FAULT_FLAG_WRITE;
+
+	/*
+	 * If for any reason at all we couldn't handle the fault,
+	 * make sure we exit gracefully rather than endlessly redo
+	 * the fault.
+	 */
+	fault = handle_mm_fault(vma, address, flags, regs);
+
+	if (fault_signal_pending(fault, regs))
+		return;
+
+	/* The fault is fully completed (including releasing mmap lock) */
+	if (fault & VM_FAULT_COMPLETED)
+		return;
+
+	if (unlikely(fault & VM_FAULT_ERROR)) {
+		if (fault & VM_FAULT_OOM)
+			goto out_of_memory;
+		else if (fault & VM_FAULT_SIGSEGV)
+			goto bad_area;
+		else if (fault & VM_FAULT_SIGBUS)
+			goto do_sigbus;
+		BUG();
+	}
+
+	if (fault & VM_FAULT_RETRY) {
+		flags |= FAULT_FLAG_TRIED;
+
+		/* No need to mmap_read_unlock(mm) as we would
+		 * have already released it in __lock_page_or_retry
+		 * in mm/filemap.c.
+		 */
+
+		goto retry;
+	}
+
+	mmap_read_unlock(mm);
+	return;
+
+	/*
+	 * Something tried to access memory that isn't in our memory map..
+	 * Fix it, but check if it's kernel or user first..
+	 */
+bad_area:
+	mmap_read_unlock(mm);
+
+bad_area_nosemaphore:
+	/* User mode accesses just cause a SIGSEGV */
+	if (from_user) {
+		do_fault_siginfo(code, SIGSEGV, regs, text_fault);
+		return;
+	}
+
+	/* Is this in ex_table? */
+no_context:
+	if (!from_user) {
+		const struct exception_table_entry *entry;
+
+		entry = search_exception_tables(regs->pc);
+#ifdef DEBUG_EXCEPTIONS
+		printk("Exception: PC<%08lx> faddr<%08lx>\n",
+		       regs->pc, address);
+		printk("EX_TABLE: insn<%08lx> fixup<%08x>\n",
+			regs->pc, entry->fixup);
+#endif
+		regs->pc = entry->fixup;
+		regs->npc = regs->pc + 4;
+		return;
+	}
+
+	unhandled_fault(address, tsk, regs);
+
+/*
+ * We ran out of memory, or some other thing happened to us that made
+ * us unable to handle the page fault gracefully.
+ */
+out_of_memory:
+	mmap_read_unlock(mm);
+	if (from_user) {
+		pagefault_out_of_memory();
+		return;
+	}
+	goto no_context;
+
+do_sigbus:
+	mmap_read_unlock(mm);
+	do_fault_siginfo(BUS_ADRERR, SIGBUS, regs, text_fault);
+	if (!from_user)
+		goto no_context;
+
+vmalloc_fault:
+	{
+		/*
+		 * Synchronize this task's top level page-table
+		 * with the 'reference' page table.
+		 */
+		int offset = pgd_index(address);
+		pgd_t *pgd, *pgd_k;
+		p4d_t *p4d, *p4d_k;
+		pud_t *pud, *pud_k;
+		pmd_t *pmd, *pmd_k;
+
+		pgd = tsk->active_mm->pgd + offset;
+		pgd_k = init_mm.pgd + offset;
+
+		if (!pgd_present(*pgd)) {
+			if (!pgd_present(*pgd_k))
+				goto bad_area_nosemaphore;
+			pgd_val(*pgd) = pgd_val(*pgd_k);
+			return;
+		}
+
+		p4d = p4d_offset(pgd, address);
+		pud = pud_offset(p4d, address);
+		pmd = pmd_offset(pud, address);
+
+		p4d_k = p4d_offset(pgd_k, address);
+		pud_k = pud_offset(p4d_k, address);
+		pmd_k = pmd_offset(pud_k, address);
+
+		if (pmd_present(*pmd) || !pmd_present(*pmd_k))
+			goto bad_area_nosemaphore;
+
+		*pmd = *pmd_k;
+		return;
+	}
+}
+
+/* This always deals with user addresses. */
+static void force_user_fault(unsigned long address, int write)
+{
+	struct vm_area_struct *vma;
+	struct task_struct *tsk = current;
+	struct mm_struct *mm = tsk->mm;
+	unsigned int flags = FAULT_FLAG_USER;
+	int code;
+
+	code = SEGV_MAPERR;
+
+	vma = lock_mm_and_find_vma(mm, address, NULL);
+	if (!vma)
+		goto bad_area_nosemaphore;
+	code = SEGV_ACCERR;
+	if (write) {
+		if (!(vma->vm_flags & VM_WRITE))
+			goto bad_area;
+		flags |= FAULT_FLAG_WRITE;
+	} else {
+		if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
+			goto bad_area;
+	}
+	switch (handle_mm_fault(vma, address, flags, NULL)) {
+	case VM_FAULT_SIGBUS:
+	case VM_FAULT_OOM:
+		goto do_sigbus;
+	}
+	mmap_read_unlock(mm);
+	return;
+bad_area:
+	mmap_read_unlock(mm);
+bad_area_nosemaphore:
+	__do_fault_siginfo(code, SIGSEGV, tsk->thread.kregs, address);
+	return;
+
+do_sigbus:
+	mmap_read_unlock(mm);
+	__do_fault_siginfo(BUS_ADRERR, SIGBUS, tsk->thread.kregs, address);
+}
+
+static void check_stack_aligned(unsigned long sp)
+{
+	if (sp & 0x7UL)
+		force_sig(SIGILL);
+}
+
+void window_overflow_fault(void)
+{
+	unsigned long sp;
+
+	sp = current_thread_info()->rwbuf_stkptrs[0];
+	if (((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
+		force_user_fault(sp + 0x38, 1);
+	force_user_fault(sp, 1);
+
+	check_stack_aligned(sp);
+}
+
+void window_underflow_fault(unsigned long sp)
+{
+	if (((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
+		force_user_fault(sp + 0x38, 0);
+	force_user_fault(sp, 0);
+
+	check_stack_aligned(sp);
+}
+
+void window_ret_fault(struct pt_regs *regs)
+{
+	unsigned long sp;
+
+	sp = regs->u_regs[UREG_FP];
+	if (((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
+		force_user_fault(sp + 0x38, 0);
+	force_user_fault(sp, 0);
+
+	check_stack_aligned(sp);
+}