Signed-off-by: NHelge Deller <deller@gmx.de>

When running the LTP testsuite one may hit this kernel BUG() with the
write06 testcase:

kernel BUG at mm/filemap.c:2023!
CPU: 1 PID: 8614 Comm: writev01 Not tainted 3.10.0-rc7-64bit-c3000+ #6
IASQ: 0000000000000000 0000000000000000 IAOQ: 00000000401e6e84 00000000401e6e88
 IIR: 03ffe01f    ISR: 0000000010340000  IOR: 000001fbe0380820
 CPU:        1   CR30: 00000000bef80000 CR31: ffffffffffffffff
 ORIG_R28: 00000000bdc192c0
 IAOQ[0]: iov_iter_advance+0x3c/0xc0
 IAOQ[1]: iov_iter_advance+0x40/0xc0
 RP(r2): generic_file_buffered_write+0x204/0x3f0
Backtrace:
 [<00000000401e764c>] generic_file_buffered_write+0x204/0x3f0
 [<00000000401eab24>] __generic_file_aio_write+0x244/0x448
 [<00000000401eadc0>] generic_file_aio_write+0x98/0x150
 [<000000004024f460>] do_sync_readv_writev+0xc0/0x130
 [<000000004025037c>] compat_do_readv_writev+0x12c/0x340
 [<00000000402505f8>] compat_writev+0x68/0xa0
 [<0000000040251d88>] compat_SyS_writev+0x98/0xf8

Reason for this crash is a gcc miscompilation in the fault handlers of
pa_memcpy() which return the fault address instead of the copied bytes.
Since this seems to be a generic problem with gcc-4.7.x (and below), it's
better to simplify the fault handlers in pa_memcpy to avoid this problem.

Here is a simple reproducer for the problem:

int main(int argc, char **argv)
{
	int fd, nbytes;
	struct iovec wr_iovec[] = {
		{ "TEST STRING                     ",32},
		{ (char*)0x40005000,32} }; // random memory.
	fd = open(DATA_FILE, O_RDWR | O_CREAT, 0666);
	nbytes = writev(fd, wr_iovec, 2);
	printf("return value = %d, errno %d (%s)\n",
		nbytes, errno, strerror(errno));
	return 0;
}

In addition, John David Anglin wrote:
There is no gcc PR as pa_memcpy is not legitimate C code. There is an
implicit assumption that certain variables will contain correct values
when an exception occurs and the code randomly jumps to one of the
exception blocks.  There is no guarantee of this.  If a PR was filed, it
would likely be marked as invalid.
Signed-off-by: NHelge Deller <deller@gmx.de>
Signed-off-by: NJohn David Anglin <dave.anglin@bell.net>
Cc: <stable@vger.kernel.org> # 3.8+
Signed-off-by: NHelge Deller <deller@gmx.de>

Avoid this warning, while still prevent gcc from optimizing away the exception code:
arch/parisc/lib/memcpy.c: In function ‘pa_memcpy’:
arch/parisc/lib/memcpy.c:256:2: warning: ‘dummy’ may be used uninitialized in this function [-Wuninitialized]
Signed-off-by: NHelge Deller <deller@gmx.de>

Add CONFIG_DEBUG_STRICT_USER_COPY_CHECKS, copied from the x86
implementation. Tested with 32 and 64bit kernel.
Signed-off-by: NHelge Deller <deller@gmx.de>
Signed-off-by: NKyle McMartin <kyle@mcmartin.ca>

>>>> I think this is what was intended? Note that this patch may affect
>>>> profiling.
>>> it really should be

> >>> -    if (likely(t1 & (sizeof(unsigned int)-1)) == 0) {
> >>> +    if (likely((t1 & (sizeof(unsigned int)-1)) == 0)) {

>>> randolph
Reported-by: NRoel Kluin <roel.kluin@gmail.com>
Signed-off-by: NRandolph Chung <tausq@parisc-linux.org>
Signed-off-by: NKyle McMartin <kyle@mcmartin.ca>

Make the following needlessly global code static:

- iomap.c: struct iomap_ops[]
- memcpy.c: pa_memcpy()
Signed-off-by: NAdrian Bunk <bunk@kernel.org>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: Grant Grundler <grundler@parisc-linux.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NKyle McMartin <kyle@mcmartin.ca>

__FUNCTION__ is gcc-specific, use __func__
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Matthew Wilcox <willy@debian.org>
Cc: Grant Grundler <grundler@parisc-linux.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NKyle McMartin <kyle@mcmartin.ca>

"extern inline" will have different semantics with gcc 4.3, and "static
inline" is correct here.
Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Cc: Matthew Wilcox <willy@debian.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NKyle McMartin <kyle@mcmartin.ca>

- this macro unifies the code to add exception table entries
- additionally use ENTRY()/ENDPROC() at more places
Signed-off-by: NHelge Deller <deller@gmx.de>
Signed-off-by: NKyle McMartin <kyle@parisc-linux.org>

Signed-off-by: NJörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: NAdrian Bunk <bunk@stusta.de>

Disable use of fpregs in pa_memcpy, and turn on the
-mdisable-fpregs flag.
Signed-off-by: NRandolph Chung <tausq@parisc-linux.org>
Signed-off-by: NKyle McMartin <kyle@parisc-linux.org>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!