This re-applies commit b91c1e3e7a ("powerpc: Fix duplicate const
clang warning in user access code") (Jun 2015) which was undone in
commits:
f2ca809059 ("powerpc/sparse: Constify the address pointer in __get_user_nosleep()") (Feb 2017)
d466f6c5ca ("powerpc/sparse: Constify the address pointer in __get_user_nocheck()") (Feb 2017)
f84ed59a61 ("powerpc/sparse: Constify the address pointer in __get_user_check()") (Feb 2017)
We see a large number of duplicate const errors in the user access
code when building with llvm/clang:
include/linux/pagemap.h:576:8: warning: duplicate 'const' declaration specifier [-Wduplicate-decl-specifier]
ret = __get_user(c, uaddr);
The problem is we are doing const __typeof__(*(ptr)), which will hit
the warning if ptr is marked const.
Removing const does not seem to have any effect on GCC code
generation.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Currently if you build a 32-bit powerpc kernel and use get_user() to
load a u64 value it will fail to build with eg:
kernel/rseq.o: In function `rseq_get_rseq_cs':
kernel/rseq.c:123: undefined reference to `__get_user_bad'
This is hitting the check in __get_user_size() that makes sure the
size we're copying doesn't exceed the size of the destination:
#define __get_user_size(x, ptr, size, retval)
do {
retval = 0;
__chk_user_ptr(ptr);
if (size > sizeof(x))
(x) = __get_user_bad();
Which doesn't immediately make sense because the size of the
destination is u64, but it's not really, because __get_user_check()
etc. internally create an unsigned long and copy into that:
#define __get_user_check(x, ptr, size)
({
long __gu_err = -EFAULT;
unsigned long __gu_val = 0;
The problem being that on 32-bit unsigned long is not big enough to
hold a u64. We can fix this with a trick from hpa in the x86 code, we
statically check the type of x and set the type of __gu_val to either
unsigned long or unsigned long long.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This patch moves ASM_CONST() and stringify_in_c() into
dedicated asm-const.h, then cleans all related inclusions.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
[mpe: asm-compat.h should include asm-const.h]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Based on the x86 commit doing the same.
See commit 304ec1b050 ("x86/uaccess: Use __uaccess_begin_nospec()
and uaccess_try_nospec") and b3bbfb3fb5 ("x86: Introduce
__uaccess_begin_nospec() and uaccess_try_nospec") for more detail.
In all cases we are ordering the load from the potentially
user-controlled pointer vs a previous branch based on an access_ok()
check or similar.
Base on a patch from Michal Suchanek.
Signed-off-by: Michal Suchanek <msuchanek@suse.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
set_fs() sets the addr_limit, which is used in access_ok() to
determine if an address is a user or kernel address.
Some code paths use set_fs() to temporarily elevate the addr_limit so
that kernel code can read/write kernel memory as if it were user
memory. That is fine as long as the code can't ever return to
userspace with the addr_limit still elevated.
If that did happen, then userspace can read/write kernel memory as if
it were user memory, eg. just with write(2). In case it's not clear,
that is very bad. It has also happened in the past due to bugs.
Commit 5ea0727b16 ("x86/syscalls: Check address limit on user-mode
return") added a mechanism to check the addr_limit value before
returning to userspace. Any call to set_fs() sets a thread flag,
TIF_FSCHECK, and if we see that on the return to userspace we go out
of line to check that the addr_limit value is not elevated.
For further info see the above commit, as well as:
https://lwn.net/Articles/722267/https://bugs.chromium.org/p/project-zero/issues/detail?id=990
Verified to work on 64-bit Book3S using a POC that objdumps the system
call handler, and a modified lkdtm_CORRUPT_USER_DS() that doesn't kill
the caller.
Before:
$ sudo ./test-tif-fscheck
...
0000000000000000 <.data>:
0: e1 f7 8a 79 rldicl. r10,r12,30,63
4: 80 03 82 40 bne 0x384
8: 00 40 8a 71 andi. r10,r12,16384
c: 78 0b 2a 7c mr r10,r1
10: 10 fd 21 38 addi r1,r1,-752
14: 08 00 c2 41 beq- 0x1c
18: 58 09 2d e8 ld r1,2392(r13)
1c: 00 00 41 f9 std r10,0(r1)
20: 70 01 61 f9 std r11,368(r1)
24: 78 01 81 f9 std r12,376(r1)
28: 70 00 01 f8 std r0,112(r1)
2c: 78 00 41 f9 std r10,120(r1)
30: 20 00 82 41 beq 0x50
34: a6 42 4c 7d mftb r10
After:
$ sudo ./test-tif-fscheck
Killed
And in dmesg:
Invalid address limit on user-mode return
WARNING: CPU: 1 PID: 3689 at ../include/linux/syscalls.h:260 do_notify_resume+0x140/0x170
...
NIP [c00000000001ee50] do_notify_resume+0x140/0x170
LR [c00000000001ee4c] do_notify_resume+0x13c/0x170
Call Trace:
do_notify_resume+0x13c/0x170 (unreliable)
ret_from_except_lite+0x70/0x74
Performance overhead is essentially zero in the usual case, because
the bit is checked as part of the existing _TIF_USER_WORK_MASK check.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
It's called 'fs' for historical reasons, it's named after the x86 'FS'
register. But we don't have to use that name for the member of
thread_struct, and in fact arch/x86 doesn't even call it 'fs' anymore.
So rename it to 'addr_limit', which better reflects what it's used
for, and is also the name used on other arches.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Pull powerpc updates from Michael Ellerman:
"A bit of a small release, I suspect in part due to me travelling for
KS. But my backlog of patches to review is smaller than usual, so I
think in part folks just didn't send as much this cycle.
Non-highlights:
- Five fixes for the >128T address space handling, both to fix bugs
in our implementation and to bring the semantics exactly into line
with x86.
Highlights:
- Support for a new OPAL call on bare metal machines which gives us a
true NMI (ie. is not masked by MSR[EE]=0) for debugging etc.
- Support for Power9 DD2 in the CXL driver.
- Improvements to machine check handling so that uncorrectable errors
can be reported into the generic memory_failure() machinery.
- Some fixes and improvements for VPHN, which is used under PowerVM
to notify the Linux partition of topology changes.
- Plumbing to enable TM (transactional memory) without suspend on
some Power9 processors (PPC_FEATURE2_HTM_NO_SUSPEND).
- Support for emulating vector loads form cache-inhibited memory, on
some Power9 revisions.
- Disable the fast-endian switch "syscall" by default (behind a
CONFIG), we believe it has never had any users.
- A major rework of the API drivers use when initiating and waiting
for long running operations performed by OPAL firmware, and changes
to the powernv_flash driver to use the new API.
- Several fixes for the handling of FP/VMX/VSX while processes are
using transactional memory.
- Optimisations of TLB range flushes when using the radix MMU on
Power9.
- Improvements to the VAS facility used to access coprocessors on
Power9, and related improvements to the way the NX crypto driver
handles requests.
- Implementation of PMEM_API and UACCESS_FLUSHCACHE for 64-bit.
Thanks to: Alexey Kardashevskiy, Alistair Popple, Allen Pais, Andrew
Donnellan, Aneesh Kumar K.V, Arnd Bergmann, Balbir Singh, Benjamin
Herrenschmidt, Breno Leitao, Christophe Leroy, Christophe Lombard,
Cyril Bur, Frederic Barrat, Gautham R. Shenoy, Geert Uytterhoeven,
Guilherme G. Piccoli, Gustavo Romero, Haren Myneni, Joel Stanley,
Kamalesh Babulal, Kautuk Consul, Markus Elfring, Masami Hiramatsu,
Michael Bringmann, Michael Neuling, Michal Suchanek, Naveen N. Rao,
Nicholas Piggin, Oliver O'Halloran, Paul Mackerras, Pedro Miraglia
Franco de Carvalho, Philippe Bergheaud, Sandipan Das, Seth Forshee,
Shriya, Stephen Rothwell, Stewart Smith, Sukadev Bhattiprolu, Tyrel
Datwyler, Vaibhav Jain, Vaidyanathan Srinivasan, and William A.
Kennington III"
* tag 'powerpc-4.15-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (151 commits)
powerpc/64s: Fix Power9 DD2.0 workarounds by adding DD2.1 feature
powerpc/64s: Fix masking of SRR1 bits on instruction fault
powerpc/64s: mm_context.addr_limit is only used on hash
powerpc/64s/radix: Fix 128TB-512TB virtual address boundary case allocation
powerpc/64s/hash: Allow MAP_FIXED allocations to cross 128TB boundary
powerpc/64s/hash: Fix fork() with 512TB process address space
powerpc/64s/hash: Fix 128TB-512TB virtual address boundary case allocation
powerpc/64s/hash: Fix 512T hint detection to use >= 128T
powerpc: Fix DABR match on hash based systems
powerpc/signal: Properly handle return value from uprobe_deny_signal()
powerpc/fadump: use kstrtoint to handle sysfs store
powerpc/lib: Implement UACCESS_FLUSHCACHE API
powerpc/lib: Implement PMEM API
powerpc/powernv/npu: Don't explicitly flush nmmu tlb
powerpc/powernv/npu: Use flush_all_mm() instead of flush_tlb_mm()
powerpc/powernv/idle: Round up latency and residency values
powerpc/kprobes: refactor kprobe_lookup_name for safer string operations
powerpc/kprobes: Blacklist emulate_update_regs() from kprobes
powerpc/kprobes: Do not disable interrupts for optprobes and kprobes_on_ftrace
powerpc/kprobes: Disable preemption before invoking probe handler for optprobes
...
Implement the architecture specific portitions of the UACCESS_FLUSHCACHE
API. This provides functions for the copy_user_flushcache iterator that
ensure that when the copy is finished the destination buffer contains
a copy of the original and that the destination buffer is clean in the
processor caches.
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.
By default all files without license information are under the default
license of the kernel, which is GPL version 2.
Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.
This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.
How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,
Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.
The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.
The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.
Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).
All documentation files were explicitly excluded.
The following heuristics were used to determine which SPDX license
identifiers to apply.
- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.
For non */uapi/* files that summary was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139
and resulted in the first patch in this series.
If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930
and resulted in the second patch in this series.
- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:
SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1
and that resulted in the third patch in this series.
- when the two scanners agreed on the detected license(s), that became
the concluded license(s).
- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.
- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).
- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.
- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.
In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.
Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.
Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.
In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.
Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct
This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.
These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
POWER9 DD2.1 and earlier has an issue where some cache inhibited
vector load will return bad data. The workaround is two part, one
firmware/microcode part triggers HMI interrupts when hitting such
loads, the other part is this patch which then emulates the
instructions in Linux.
The affected instructions are limited to lxvd2x, lxvw4x, lxvb16x and
lxvh8x.
When an instruction triggers the HMI, all threads in the core will be
sent to the HMI handler, not just the one running the vector load.
In general, these spurious HMIs are detected by the emulation code and
we just return back to the running process. Unfortunately, if a
spurious interrupt occurs on a vector load that's to normal memory we
have no way to detect that it's spurious (unless we walk the page
tables, which is very expensive). In this case we emulate the load but
we need do so using a vector load itself to ensure 128bit atomicity is
preserved.
Some additional debugfs emulated instruction counters are added also.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[mpe: Switch CONFIG_PPC_BOOK3S_64 to CONFIG_VSX to unbreak the build]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Pull uacess-unaligned removal from Al Viro:
"That stuff had just one user, and an exotic one, at that - binfmt_flat
on arm and m68k"
* 'work.uaccess-unaligned' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
kill {__,}{get,put}_user_unaligned()
binfmt_flat: flat_{get,put}_addr_from_rp() should be able to fail
Pull user access str* updates from Al Viro:
"uaccess str...() dead code removal"
* 'uaccess.strlen' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
s390 keyboard.c: don't open-code strndup_user()
mips: get rid of unused __strnlen_user()
get rid of unused __strncpy_from_user() instances
kill strlen_user()
Larry Finger reported that his Powerbook G4 was no longer booting with v4.12-rc,
userspace was up but giving weird errors such as:
udevd[64]: starting version 175
udevd[64]: Unable to receive ctrl message: Bad address.
modprobe: chdir(4.12-rc1): No such file or directory
He bisected the problem to commit 3448890c32 ("powerpc: get rid of zeroing,
switch to RAW_COPY_USER").
Al identified that the problem is actually a miscompilation by GCC 4.6.3, which
is exposed by the above commit.
Al also pointed out that inlining copy_to/from_user() is probably of little or
no benefit, which is correct. Using Anton's copy_to_user benchmark, with a
pathological single byte copy, we see a small increase in performance
by *removing* inlining:
Before (inlined):
# time ./copy_to_user -w -l 1 -i 10000000 ( x 3 )
real 0m22.063s
real 0m22.059s
real 0m22.076s
After:
# time ./copy_to_user -w -l 1 -i 10000000 ( x 3 )
real 0m21.325s
real 0m21.299s
real 0m21.364s
So as a small performance improvement and to avoid the miscompilation, drop
inlining copy_to/from_user() on 32-bit.
Fixes: 3448890c32 ("powerpc: get rid of zeroing, switch to RAW_COPY_USER")
Reported-by: Larry Finger <Larry.Finger@lwfinger.net>
Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
None of those file is ever included from uapi stuff, so __KERNEL__
is always defined. None of them is ever included from assembler
(they are only pulled from linux/uaccess.h, which _can't_ be
included from assembler), so __ASSEMBLY__ is never defined.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
In __get_user_nosleep, we create an intermediate pointer for the
user address we're about to fetch. We currently don't tag this
pointer as const. Make it const, as we are simply dereferencing
it, and it's scope is limited to the __get_user_nosleep macro.
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
In __get_user_nocheck, we create an intermediate pointer for the
user address we're about to fetch. We currently don't tag this
pointer as const. Make it const, as we are simply dereferencing
it, and it's scope is limited to the __get_user_nocheck macro.
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
In __get_user_check, we create an intermediate pointer for the
user address we're about to fetch. We currently don't tag this
pointer as const. Make it const, as we are simply dereferencing
it, and it's scope is limited to the __get_user_check macro.
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This halves the exception table size on 64-bit builds, and it allows
build-time sorting of exception tables to work on relocated kernels.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Minor asm fixups and bits to keep the selftests working]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Anton Blanchard
Michael Ellerman
Christophe Leroy
Mathieu Malaterre
Linus Torvalds
Oliver O'Halloran
Greg Kroah-Hartman
Michael Neuling
Al Viro
Daniel Axtens
Nicholas Piggin