Commit 8780356e authored by Dan Williams's avatar Dan Williams Committed by Ingo Molnar
Browse files

x86/asm/memcpy_mcsafe: Define copy_to_iter_mcsafe() 



Use the updated memcpy_mcsafe() implementation to define
copy_user_mcsafe() and copy_to_iter_mcsafe(). The most significant
difference from typical copy_to_iter() is that the ITER_KVEC and
ITER_BVEC iterator types can fail to complete a full transfer.

Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: hch@lst.de
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-nvdimm@lists.01.org
Link: http://lkml.kernel.org/r/152539239150.31796.9189779163576449784.stgit@dwillia2-desk3.amr.corp.intel.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 12c89130

arch/x86/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -60,6 +60,7 @@ config X86 
	select ARCH_HAS_PMEM_API		if X86_64

	select ARCH_HAS_REFCOUNT

	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64

	select ARCH_HAS_UACCESS_MCSAFE		if X86_64

	select ARCH_HAS_SET_MEMORY

	select ARCH_HAS_SG_CHAIN

	select ARCH_HAS_STRICT_KERNEL_RWX

arch/x86/include/asm/uaccess_64.h

+11 −0
Original line number Diff line number Diff line
@@ -46,6 +46,17 @@ copy_user_generic(void *to, const void *from, unsigned len) 
	return ret;

}



static __always_inline __must_check unsigned long

copy_to_user_mcsafe(void *to, const void *from, unsigned len)

{

	unsigned long ret;



	__uaccess_begin();

	ret = memcpy_mcsafe(to, from, len);

	__uaccess_end();

	return ret;

}



static __always_inline __must_check unsigned long

raw_copy_from_user(void *dst, const void __user *src, unsigned long size)

{

include/linux/uio.h

+15 −0
Original line number Diff line number Diff line
@@ -154,6 +154,12 @@ size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i); 
#define _copy_from_iter_flushcache _copy_from_iter_nocache

#endif



#ifdef CONFIG_ARCH_HAS_UACCESS_MCSAFE

size_t _copy_to_iter_mcsafe(void *addr, size_t bytes, struct iov_iter *i);

#else

#define _copy_to_iter_mcsafe _copy_to_iter

#endif



static __always_inline __must_check

size_t copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i)

{
@@ -163,6 +169,15 @@ size_t copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i) 
		return _copy_from_iter_flushcache(addr, bytes, i);

}



static __always_inline __must_check

size_t copy_to_iter_mcsafe(void *addr, size_t bytes, struct iov_iter *i)

{

	if (unlikely(!check_copy_size(addr, bytes, false)))

		return 0;

	else

		return _copy_to_iter_mcsafe(addr, bytes, i);

}



size_t iov_iter_zero(size_t bytes, struct iov_iter *);

unsigned long iov_iter_alignment(const struct iov_iter *i);

unsigned long iov_iter_gap_alignment(const struct iov_iter *i);

lib/iov_iter.c

+61 −0
Original line number Diff line number Diff line
@@ -573,6 +573,67 @@ size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) 
}

EXPORT_SYMBOL(_copy_to_iter);



#ifdef CONFIG_ARCH_HAS_UACCESS_MCSAFE

static int copyout_mcsafe(void __user *to, const void *from, size_t n)

{

	if (access_ok(VERIFY_WRITE, to, n)) {

		kasan_check_read(from, n);

		n = copy_to_user_mcsafe((__force void *) to, from, n);

	}

	return n;

}



static unsigned long memcpy_mcsafe_to_page(struct page *page, size_t offset,

		const char *from, size_t len)

{

	unsigned long ret;

	char *to;



	to = kmap_atomic(page);

	ret = memcpy_mcsafe(to + offset, from, len);

	kunmap_atomic(to);



	return ret;

}



size_t _copy_to_iter_mcsafe(const void *addr, size_t bytes, struct iov_iter *i)

{

	const char *from = addr;

	unsigned long rem, curr_addr, s_addr = (unsigned long) addr;



	if (unlikely(i->type & ITER_PIPE)) {

		WARN_ON(1);

		return 0;

	}

	if (iter_is_iovec(i))

		might_fault();

	iterate_and_advance(i, bytes, v,

		copyout_mcsafe(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len),

		({

		rem = memcpy_mcsafe_to_page(v.bv_page, v.bv_offset,

                               (from += v.bv_len) - v.bv_len, v.bv_len);

		if (rem) {

			curr_addr = (unsigned long) from;

			bytes = curr_addr - s_addr - rem;

			return bytes;

		}

		}),

		({

		rem = memcpy_mcsafe(v.iov_base, (from += v.iov_len) - v.iov_len,

				v.iov_len);

		if (rem) {

			curr_addr = (unsigned long) from;

			bytes = curr_addr - s_addr - rem;

			return bytes;

		}

		})

	)



	return bytes;

}

EXPORT_SYMBOL_GPL(_copy_to_iter_mcsafe);

#endif /* CONFIG_ARCH_HAS_UACCESS_MCSAFE */



size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)

{

	char *to = addr;

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