linux/arch/x86/lib
Toshi Kani a82eee7424 x86/uaccess/64: Handle the caching of 4-byte nocache copies properly in __copy_user_nocache()
Data corruption issues were observed in tests which initiated
a system crash/reset while accessing BTT devices.  This problem
is reproducible.

The BTT driver calls pmem_rw_bytes() to update data in pmem
devices.  This interface calls __copy_user_nocache(), which
uses non-temporal stores so that the stores to pmem are
persistent.

__copy_user_nocache() uses non-temporal stores when a request
size is 8 bytes or larger (and is aligned by 8 bytes).  The
BTT driver updates the BTT map table, which entry size is
4 bytes.  Therefore, updates to the map table entries remain
cached, and are not written to pmem after a crash.

Change __copy_user_nocache() to use non-temporal store when
a request size is 4 bytes.  The change extends the current
byte-copy path for a less-than-8-bytes request, and does not
add any overhead to the regular path.

Reported-and-tested-by: Micah Parrish <micah.parrish@hpe.com>
Reported-and-tested-by: Brian Boylston <brian.boylston@hpe.com>
Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Cc: <stable@vger.kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: linux-nvdimm@lists.01.org
Link: http://lkml.kernel.org/r/1455225857-12039-3-git-send-email-toshi.kani@hpe.com
[ Small readability edits. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-02-17 09:10:23 +01:00
..
.gitignore x86: Gitignore: arch/x86/lib/inat-tables.c 2009-11-04 13:11:28 +01:00
Makefile x86/cpu: Unify CPU family, model, stepping calculation 2015-11-24 09:15:54 +01:00
atomic64_32.c x86: Adjust asm constraints in atomic64 wrappers 2012-01-20 17:29:31 -08:00
atomic64_386_32.S x86/debug: Remove perpetually broken, unmaintainable dwarf annotations 2015-06-02 07:57:48 +02:00
atomic64_cx8_32.S x86/debug: Remove perpetually broken, unmaintainable dwarf annotations 2015-06-02 07:57:48 +02:00
cache-smp.c x86, lib: Add wbinvd smp helpers 2010-01-22 16:05:42 -08:00
checksum_32.S x86/debug: Remove perpetually broken, unmaintainable dwarf annotations 2015-06-02 07:57:48 +02:00
clear_page_64.S x86/debug: Remove perpetually broken, unmaintainable dwarf annotations 2015-06-02 07:57:48 +02:00
cmdline.c x86, boot: Carve out early cmdline parsing function 2014-05-20 20:21:24 -07:00
cmpxchg8b_emu.S x86/debug: Remove perpetually broken, unmaintainable dwarf annotations 2015-06-02 07:57:48 +02:00
cmpxchg16b_emu.S x86/debug: Remove perpetually broken, unmaintainable dwarf annotations 2015-06-02 07:57:48 +02:00
copy_page_64.S x86/debug: Remove perpetually broken, unmaintainable dwarf annotations 2015-06-02 07:57:48 +02:00
copy_user_64.S x86/uaccess/64: Handle the caching of 4-byte nocache copies properly in __copy_user_nocache() 2016-02-17 09:10:23 +01:00
cpu.c x86/cpu: Unify CPU family, model, stepping calculation 2015-11-24 09:15:54 +01:00
csum-copy_64.S x86/debug: Remove perpetually broken, unmaintainable dwarf annotations 2015-06-02 07:57:48 +02:00
csum-partial_64.c x86: Fix common misspellings 2011-03-18 10:39:30 +01:00
csum-wrappers_64.c x86-64: make csum_partial_copy_from_user() error handling consistent 2014-11-16 11:00:42 -08:00
delay.c x86/asm/delay: Introduce an MWAITX-based delay with a configurable timer 2015-08-22 14:52:16 +02:00
getuser.S x86/debug: Remove perpetually broken, unmaintainable dwarf annotations 2015-06-02 07:57:48 +02:00
inat.c x86: Fix to decode grouped AVX with VEX pp bits 2012-02-11 15:11:35 +01:00
insn.c x86/asm/decoder: Fix and enforce max instruction size in the insn decoder 2015-02-19 00:01:24 +01:00
iomap_copy_64.S x86/debug: Remove perpetually broken, unmaintainable dwarf annotations 2015-06-02 07:57:48 +02:00
memcpy_32.c asmlinkage, x86: Fix 32bit memcpy for LTO 2014-02-13 18:14:46 -08:00
memcpy_64.S x86/debug: Remove perpetually broken, unmaintainable dwarf annotations 2015-06-02 07:57:48 +02:00
memmove_64.S x86/debug: Remove perpetually broken, unmaintainable dwarf annotations 2015-06-02 07:57:48 +02:00
memset_64.S x86/debug: Remove perpetually broken, unmaintainable dwarf annotations 2015-06-02 07:57:48 +02:00
misc.c x86/boot: Further compress CPUs bootup message 2013-10-01 10:52:30 +02:00
mmx_32.c x86/fpu: Rename i387.h to fpu/api.h 2015-05-19 15:47:30 +02:00
msr-reg-export.c x86, pvops: Remove hooks for {rd,wr}msr_safe_regs 2012-06-07 11:41:08 -07:00
msr-reg.S x86/debug: Remove perpetually broken, unmaintainable dwarf annotations 2015-06-02 07:57:48 +02:00
msr-smp.c x86 / msr: add 64bit _on_cpu access functions 2013-10-17 00:36:06 +02:00
msr.c x86, tracing, perf: Add trace point for MSR accesses 2015-12-06 12:56:10 +01:00
putuser.S x86/debug: Remove perpetually broken, unmaintainable dwarf annotations 2015-06-02 07:57:48 +02:00
rwsem.S x86/debug: Remove perpetually broken, unmaintainable dwarf annotations 2015-06-02 07:57:48 +02:00
string_32.c x86/i386: Use less assembly in strlen(), speed things up a bit 2011-12-12 18:33:42 +01:00
strstr_32.c x86: coding style fixes to arch/x86/lib/strstr_32.c 2008-08-15 16:53:24 +02:00
usercopy.c perf/x86: Fix copy_from_user_nmi() return if range is not ok 2015-07-06 14:09:27 +02:00
usercopy_32.c mm/uaccess, mm/fault: Clarify that uaccess may only sleep if pagefaults are enabled 2015-05-19 08:39:14 +02:00
usercopy_64.c x86: fix special __probe_kernel_write() tail zeroing case 2015-04-24 06:58:27 -07:00
x86-opcode-map.txt x86/insn: perf tools: Add new xsave instructions 2015-09-04 12:01:04 -03:00