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: Dan 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: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Dan Williams 2018-05-03 17:06:31 -07:00 committed by Ingo Molnar
parent 12c89130a5
commit 8780356ef6
4 changed files with 88 additions and 0 deletions

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@ -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

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@ -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)
{

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@ -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);

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@ -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;