user/sven/linux.git, branch v3.18.50

Linux 3.18.50

2017-04-22T05:15:42Z

give up on gcc ilog2() constant optimizations

2017-04-22T05:15:07Z

commit 474c90156c8dcc2fa815e6716cc9394d7930cb9c upstream. gcc-7 has an "optimization" pass that completely screws up, and generates the code expansion for the (impossible) case of calling ilog2() with a zero constant, even when the code gcc compiles does not actually have a zero constant. And we try to generate a compile-time error for anybody doing ilog2() on a constant where that doesn't make sense (be it zero or negative). So now gcc7 will fail the build due to our sanity checking, because it created that constant-zero case that didn't actually exist in the source code. There's a whole long discussion on the kernel mailing about how to work around this gcc bug. The gcc people themselevs have discussed their "feature" in https://gcc.gnu.org/bugzilla/show_bug.cgi?id=72785 but it's all water under the bridge, because while it looked at one point like it would be solved by the time gcc7 was released, that was not to be. So now we have to deal with this compiler braindamage. And the only simple approach seems to be to just delete the code that tries to warn about bad uses of ilog2(). So now "ilog2()" will just return 0 not just for the value 1, but for any non-positive value too. It's not like I can recall anybody having ever actually tried to use this function on any invalid value, but maybe the sanity check just meant that such code never made it out in public. Reported-by: Laura Abbott Cc: John Stultz , Cc: Thomas Gleixner Cc: Ard Biesheuvel Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

metag/usercopy: Add missing fixups

2017-04-22T05:15:07Z

commit b884a190afcecdbef34ca508ea5ee88bb7c77861 upstream. The rapf copy loops in the Meta usercopy code is missing some extable entries for HTP cores with unaligned access checking enabled, where faults occur on the instruction immediately after the faulting access. Add the fixup labels and extable entries for these cases so that corner case user copy failures don't cause kernel crashes. Fixes: 373cd784d0fc ("metag: Memory handling") Signed-off-by: James Hogan Cc: linux-metag@vger.kernel.org Signed-off-by: Greg Kroah-Hartman

metag/usercopy: Fix src fixup in from user rapf loops

2017-04-22T05:15:07Z

commit 2c0b1df88b987a12d95ea1d6beaf01894f3cc725 upstream. The fixup code to rewind the source pointer in __asm_copy_from_user_{32,64}bit_rapf_loop() always rewound the source by a single unit (4 or 8 bytes), however this is insufficient if the fault didn't occur on the first load in the loop, as the source pointer will have been incremented but nothing will have been stored until all 4 register [pairs] are loaded. Read the LSM_STEP field of TXSTATUS (which is already loaded into a register), a bit like the copy_to_user versions, to determine how many iterations of MGET[DL] have taken place, all of which need rewinding. Fixes: 373cd784d0fc ("metag: Memory handling") Signed-off-by: James Hogan Cc: linux-metag@vger.kernel.org Signed-off-by: Greg Kroah-Hartman

metag/usercopy: Set flags before ADDZ

2017-04-22T05:15:07Z

commit fd40eee1290ad7add7aa665e3ce6b0f9fe9734b4 upstream. The fixup code for the copy_to_user rapf loops reads TXStatus.LSM_STEP to decide how far to rewind the source pointer. There is a special case for the last execution of an MGETL/MGETD, since it leaves LSM_STEP=0 even though the number of MGETLs/MGETDs attempted was 4. This uses ADDZ which is conditional upon the Z condition flag, but the AND instruction which masked the TXStatus.LSM_STEP field didn't set the condition flags based on the result. Fix that now by using ANDS which does set the flags, and also marking the condition codes as clobbered by the inline assembly. Fixes: 373cd784d0fc ("metag: Memory handling") Signed-off-by: James Hogan Cc: linux-metag@vger.kernel.org Signed-off-by: Greg Kroah-Hartman

metag/usercopy: Zero rest of buffer from copy_from_user

2017-04-22T05:15:07Z

commit 563ddc1076109f2b3f88e6d355eab7b6fd4662cb upstream. Currently we try to zero the destination for a failed read from userland in fixup code in the usercopy.c macros. The rest of the destination buffer is then zeroed from __copy_user_zeroing(), which is used for both copy_from_user() and __copy_from_user(). Unfortunately we fail to zero in the fixup code as D1Ar1 is set to 0 before the fixup code entry labels, and __copy_from_user() shouldn't even be zeroing the rest of the buffer. Move the zeroing out into copy_from_user() and rename __copy_user_zeroing() to raw_copy_from_user() since it no longer does any zeroing. This also conveniently matches the name needed for RAW_COPY_USER support in a later patch. Fixes: 373cd784d0fc ("metag: Memory handling") Reported-by: Al Viro Signed-off-by: James Hogan Cc: linux-metag@vger.kernel.org Signed-off-by: Greg Kroah-Hartman

metag/usercopy: Add early abort to copy_to_user

2017-04-22T05:15:06Z

commit fb8ea062a8f2e85256e13f55696c5c5f0dfdcc8b upstream. When copying to userland on Meta, if any faults are encountered immediately abort the copy instead of continuing on and repeatedly faulting, and worse potentially copying further bytes successfully to subsequent valid pages. Fixes: 373cd784d0fc ("metag: Memory handling") Reported-by: Al Viro Signed-off-by: James Hogan Cc: linux-metag@vger.kernel.org Signed-off-by: Greg Kroah-Hartman

metag/usercopy: Fix alignment error checking

2017-04-22T05:15:06Z

commit 2257211942bbbf6c798ab70b487d7e62f7835a1a upstream. Fix the error checking of the alignment adjustment code in raw_copy_from_user(), which mistakenly considers it safe to skip the error check when aligning the source buffer on a 2 or 4 byte boundary. If the destination buffer was unaligned it may have started to copy using byte or word accesses, which could well be at the start of a new (valid) source page. This would result in it appearing to have copied 1 or 2 bytes at the end of the first (invalid) page rather than none at all. Fixes: 373cd784d0fc ("metag: Memory handling") Signed-off-by: James Hogan Cc: linux-metag@vger.kernel.org Signed-off-by: Greg Kroah-Hartman

metag/usercopy: Drop unused macros

2017-04-22T05:15:06Z

commit ef62a2d81f73d9cddef14bc3d9097a57010d551c upstream. Metag's lib/usercopy.c has a bunch of copy_from_user macros for larger copies between 5 and 16 bytes which are completely unused. Before fixing zeroing lets drop these macros so there is less to fix. Signed-off-by: James Hogan Cc: Al Viro Cc: linux-metag@vger.kernel.org Signed-off-by: Greg Kroah-Hartman

ring-buffer: Fix return value check in test_ringbuffer()

2017-04-22T05:15:06Z

commit 62277de758b155dc04b78f195a1cb5208c37b2df upstream. In case of error, the function kthread_run() returns ERR_PTR() and never returns NULL. The NULL test in the return value check should be replaced with IS_ERR(). Link: http://lkml.kernel.org/r/1466184839-14927-1-git-send-email-weiyj_lk@163.com Fixes: 6c43e554a ("ring-buffer: Add ring buffer startup selftest") Signed-off-by: Wei Yongjun Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Greg Kroah-Hartman