path: root/arch/sparc/kernel/ptrace_64.c

/* ptrace.c: Sparc process tracing support.
 *
 * Copyright (C) 1996, 2008 David S. Miller (davem@davemloft.net)
 * Copyright (C) 1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
 *
 * Based upon code written by Ross Biro, Linus Torvalds, Bob Manson,
 * and David Mosberger.
 *
 * Added Linux support -miguel (weird, eh?, the original code was meant
 * to emulate SunOS).
 */

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/smp.h>
#include <linux/security.h>
#include <linux/seccomp.h>
#include <linux/audit.h>
#include <linux/signal.h>
#include <linux/regset.h>
#include <linux/tracehook.h>
#include <trace/syscall.h>
#include <linux/compat.h>
#include <linux/elf.h>

#include <asm/asi.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/psrcompat.h>
#include <asm/visasm.h>
#include <asm/spitfire.h>
#include <asm/page.h>
#include <asm/cpudata.h>
#include <asm/cacheflush.h>

#define CREATE_TRACE_POINTS
#include <trace/events/syscalls.h>

#include "entry.h"

/* #define ALLOW_INIT_TRACING */

/*
 * Called by kernel/ptrace.c when detaching..
 *
 * Make sure single step bits etc are not set.
 */
void ptrace_disable(struct task_struct *child)
{
	/* nothing to do */
}

/* To get the necessary page struct, access_process_vm() first calls
 * get_user_pages().  This has done a flush_dcache_page() on the
 * accessed page.  Then our caller (copy_{to,from}_user_page()) did
 * to memcpy to read/write the data from that page.
 *
 * Now, the only thing we have to do is:
 * 1) flush the D-cache if it's possible than an illegal alias
 *    has been created
 * 2) flush the I-cache if this is pre-cheetah and we did a write
 */
void flush_ptrace_access(struct vm_area_struct *vma, struct page *page,
			 unsigned long uaddr, void *kaddr,
			 unsigned long len, int write)
{
	BUG_ON(len > PAGE_SIZE);

	if (tlb_type == hypervisor)
		return;

	preempt_disable();

#ifdef DCACHE_ALIASING_POSSIBLE
	/* If bit 13 of the kernel address we used to access the
	 * user page is the same as the virtual address that page
	 * is mapped to in the user's address space, we can skip the
	 * D-cache flush.
	 */
	if ((uaddr ^ (unsigned long) kaddr) & (1UL << 13)) {
		unsigned long start = __pa(kaddr);
		unsigned long end = start + len;
		unsigned long dcache_line_size;

		dcache_line_size = local_cpu_data().dcache_line_size;

		if (tlb_type == spitfire) {
			for (; start < end; start += dcache_line_size)
				spitfire_put_dcache_tag(start & 0x3fe0, 0x0);
		} else {
			start &= ~(dcache_line_size - 1);
			for (; start < end; start += dcache_line_size)
				__asm__ __volatile__(
					"stxa %%g0, [%0] %1\n\t"
					"membar #Sync"
					: /* no outputs */
					: "r" (start),
					"i" (ASI_DCACHE_INVALIDATE));
		}
	}
#endif
	if (write && tlb_type == spitfire) {
		unsigned long start = (unsigned long) kaddr;
		unsigned long end = start + len;
		unsigned long icache_line_size;

		icache_line_size = local_cpu_data().icache_line_size;

		for (; start < end; start += icache_line_size)
			flushi(start);
	}

	preempt_enable();
}

static int get_from_target(struct task_struct *target, unsigned long uaddr,
			   void *kbuf, int len)
{
	if (target == current) {
		if (copy_from_user(kbuf, (void __user *) uaddr, len))
			return -EFAULT;
	} else {
		int len2 = access_process_vm(target, uaddr, kbuf, len, 0);
		if (len2 != len)
			return -EFAULT;
	}
	return 0;
}

static int set_to_target(struct task_struct *target, unsigned long uaddr,
			 void *kbuf, int len)
{
	if (target == current) {
		if (copy_to_user((void __user *) uaddr, kbuf, len))
			return -EFAULT;
	} else