This series finally gets us to the point of having system calls with
64-bit time_t on all architectures, after a long time of incremental
preparation patches.
There was actually one conversion that I missed during the summer,
i.e. Deepa's timex series, which I now updated based the 5.0-rc1 changes
and review comments.
The following system calls are now added on all 32-bit architectures
using the same system call numbers:
403 clock_gettime64
404 clock_settime64
405 clock_adjtime64
406 clock_getres_time64
407 clock_nanosleep_time64
408 timer_gettime64
409 timer_settime64
410 timerfd_gettime64
411 timerfd_settime64
412 utimensat_time64
413 pselect6_time64
414 ppoll_time64
416 io_pgetevents_time64
417 recvmmsg_time64
418 mq_timedsend_time64
419 mq_timedreceiv_time64
420 semtimedop_time64
421 rt_sigtimedwait_time64
422 futex_time64
423 sched_rr_get_interval_time64
Each one of these corresponds directly to an existing system call
that includes a 'struct timespec' argument, or a structure containing
a timespec or (in case of clock_adjtime) timeval. Not included here
are new versions of getitimer/setitimer and getrusage/waitid, which
are planned for the future but only needed to make a consistent API
rather than for correct operation beyond y2038. These four system
calls are based on 'timeval', and it has not been finally decided
what the replacement kernel interface will use instead.
So far, I have done a lot of build testing across most architectures,
which has found a number of bugs. Runtime testing so far included
testing LTP on 32-bit ARM with the existing system calls, to ensure
we do not regress for existing binaries, and a test with a 32-bit
x86 build of LTP against a modified version of the musl C library
that has been adapted to the new system call interface [3].
This library can be used for testing on all architectures supported
by musl-1.1.21, but it is not how the support is getting integrated
into the official musl release. Official musl support is planned
but will require more invasive changes to the library.
Link: https://lore.kernel.org/lkml/20190110162435.309262-1-arnd@arndb.de/T/
Link: https://lore.kernel.org/lkml/20190118161835.2259170-1-arnd@arndb.de/
Link: https://git.linaro.org/people/arnd/musl-y2038.git/ [2]
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
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Merge tag 'y2038-new-syscalls' of git://git.kernel.org:/pub/scm/linux/kernel/git/arnd/playground into timers/2038
Pull y2038 - time64 system calls from Arnd Bergmann:
This series finally gets us to the point of having system calls with 64-bit
time_t on all architectures, after a long time of incremental preparation
patches.
There was actually one conversion that I missed during the summer,
i.e. Deepa's timex series, which I now updated based the 5.0-rc1 changes
and review comments.
The following system calls are now added on all 32-bit architectures using
the same system call numbers:
403 clock_gettime64
404 clock_settime64
405 clock_adjtime64
406 clock_getres_time64
407 clock_nanosleep_time64
408 timer_gettime64
409 timer_settime64
410 timerfd_gettime64
411 timerfd_settime64
412 utimensat_time64
413 pselect6_time64
414 ppoll_time64
416 io_pgetevents_time64
417 recvmmsg_time64
418 mq_timedsend_time64
419 mq_timedreceiv_time64
420 semtimedop_time64
421 rt_sigtimedwait_time64
422 futex_time64
423 sched_rr_get_interval_time64
Each one of these corresponds directly to an existing system call that
includes a 'struct timespec' argument, or a structure containing a timespec
or (in case of clock_adjtime) timeval. Not included here are new versions
of getitimer/setitimer and getrusage/waitid, which are planned for the
future but only needed to make a consistent API rather than for correct
operation beyond y2038. These four system calls are based on 'timeval', and
it has not been finally decided what the replacement kernel interface will
use instead.
So far, I have done a lot of build testing across most architectures, which
has found a number of bugs. Runtime testing so far included testing LTP on
32-bit ARM with the existing system calls, to ensure we do not regress for
existing binaries, and a test with a 32-bit x86 build of LTP against a
modified version of the musl C library that has been adapted to the new
system call interface [3]. This library can be used for testing on all
architectures supported by musl-1.1.21, but it is not how the support is
getting integrated into the official musl release. Official musl support is
planned but will require more invasive changes to the library.
Link: https://lore.kernel.org/lkml/20190110162435.309262-1-arnd@arndb.de/T/
Link: https://lore.kernel.org/lkml/20190118161835.2259170-1-arnd@arndb.de/
Link: https://git.linaro.org/people/arnd/musl-y2038.git/ [2]
The system call tables have diverged a bit over the years, and a number
of the recent additions never made it into all architectures, for one
reason or another.
This is an attempt to clean it up as far as we can without breaking
compatibility, doing a number of steps:
- Add system calls that have not yet been integrated into all
architectures but that we definitely want there. This includes
{,f}statfs64() and get{eg,eu,g,p,u,pp}id() on alpha, which have
been missing traditionally.
- The s390 compat syscall handling is cleaned up to be more like
what we do on other architectures, while keeping the 31-bit
pointer extension. This was merged as a shared branch by the
s390 maintainers and is included here in order to base the other
patches on top.
- Add the separate ipc syscalls on all architectures that
traditionally only had sys_ipc(). This version is done without
support for IPC_OLD that is we have in sys_ipc. The
new semtimedop_time64 syscall will only be added here, not
in sys_ipc
- Add syscall numbers for a couple of syscalls that we probably
don't need everywhere, in particular pkey_* and rseq,
for the purpose of symmetry: if it's in asm-generic/unistd.h,
it makes sense to have it everywhere. I expect that any future
system calls will get assigned on all platforms together, even
when they appear to be specific to a single architecture.
- Prepare for having the same system call numbers for any future
calls. In combination with the generated tables, this hopefully
makes it easier to add new calls across all architectures
together.
All of the above are technically separate from the y2038 work,
but are done as preparation before we add the new 64-bit time_t
system calls everywhere, providing a common baseline set of system
calls.
I expect that glibc and other libraries that want to use 64-bit
time_t will require linux-5.1 kernel headers for building in
the future, and at a much later point may also require linux-5.1
or a later version as the minimum kernel at runtime. Having a
common baseline then allows the removal of many architecture or
kernel version specific workarounds.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
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Merge tag 'y2038-syscall-cleanup' of git://git.kernel.org:/pub/scm/linux/kernel/git/arnd/playground into timers/2038
Pull preparatory work for y2038 changes from Arnd Bergmann:
System call unification and cleanup
The system call tables have diverged a bit over the years, and a number of
the recent additions never made it into all architectures, for one reason
or another.
This is an attempt to clean it up as far as we can without breaking
compatibility, doing a number of steps:
- Add system calls that have not yet been integrated into all architectures
but that we definitely want there. This includes {,f}statfs64() and
get{eg,eu,g,p,u,pp}id() on alpha, which have been missing traditionally.
- The s390 compat syscall handling is cleaned up to be more like what we
do on other architectures, while keeping the 31-bit pointer
extension. This was merged as a shared branch by the s390 maintainers
and is included here in order to base the other patches on top.
- Add the separate ipc syscalls on all architectures that traditionally
only had sys_ipc(). This version is done without support for IPC_OLD
that is we have in sys_ipc. The new semtimedop_time64 syscall will only
be added here, not in sys_ipc
- Add syscall numbers for a couple of syscalls that we probably don't need
everywhere, in particular pkey_* and rseq, for the purpose of symmetry:
if it's in asm-generic/unistd.h, it makes sense to have it everywhere. I
expect that any future system calls will get assigned on all platforms
together, even when they appear to be specific to a single architecture.
- Prepare for having the same system call numbers for any future calls. In
combination with the generated tables, this hopefully makes it easier to
add new calls across all architectures together.
All of the above are technically separate from the y2038 work, but are done
as preparation before we add the new 64-bit time_t system calls everywhere,
providing a common baseline set of system calls.
I expect that glibc and other libraries that want to use 64-bit time_t will
require linux-5.1 kernel headers for building in the future, and at a much
later point may also require linux-5.1 or a later version as the minimum
kernel at runtime. Having a common baseline then allows the removal of many
architecture or kernel version specific workarounds.
This adds 21 new system calls on each ABI that has 32-bit time_t
today. All of these have the exact same semantics as their existing
counterparts, and the new ones all have macro names that end in 'time64'
for clarification.
This gets us to the point of being able to safely use a C library
that has 64-bit time_t in user space. There are still a couple of
loose ends to tie up in various areas of the code, but this is the
big one, and should be entirely uncontroversial at this point.
In particular, there are four system calls (getitimer, setitimer,
waitid, and getrusage) that don't have a 64-bit counterpart yet,
but these can all be safely implemented in the C library by wrapping
around the existing system calls because the 32-bit time_t they
pass only counts elapsed time, not time since the epoch. They
will be dealt with later.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
The time, stime, utime, utimes, and futimesat system calls are only
used on older architectures, and we do not provide y2038 safe variants
of them, as they are replaced by clock_gettime64, clock_settime64,
and utimensat_time64.
However, for consistency it seems better to have the 32-bit architectures
that still use them call the "time32" entry points (leaving the
traditional handlers for the 64-bit architectures), like we do for system
calls that now require two versions.
Note: We used to always define __ARCH_WANT_SYS_TIME and
__ARCH_WANT_SYS_UTIME and only set __ARCH_WANT_COMPAT_SYS_TIME and
__ARCH_WANT_SYS_UTIME32 for compat mode on 64-bit kernels. Now this is
reversed: only 64-bit architectures set __ARCH_WANT_SYS_TIME/UTIME, while
we need __ARCH_WANT_SYS_TIME32/UTIME32 for 32-bit architectures and compat
mode. The resulting asm/unistd.h changes look a bit counterintuitive.
This is only a cleanup patch and it should not change any behavior.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
This is the big flip, where all 32-bit architectures set COMPAT_32BIT_TIME
and use the _time32 system calls from the former compat layer instead
of the system calls that take __kernel_timespec and similar arguments.
The temporary redirects for __kernel_timespec, __kernel_itimerspec
and __kernel_timex can get removed with this.
It would be easy to split this commit by architecture, but with the new
generated system call tables, it's easy enough to do it all at once,
which makes it a little easier to check that the changes are the same
in each table.
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
A lot of system calls that pass a time_t somewhere have an implementation
using a COMPAT_SYSCALL_DEFINEx() on 64-bit architectures, and have
been reworked so that this implementation can now be used on 32-bit
architectures as well.
The missing step is to redefine them using the regular SYSCALL_DEFINEx()
to get them out of the compat namespace and make it possible to build them
on 32-bit architectures.
Any system call that ends in 'time' gets a '32' suffix on its name for
that version, while the others get a '_time32' suffix, to distinguish
them from the normal version, which takes a 64-bit time argument in the
future.
In this step, only 64-bit architectures are changed, doing this rename
first lets us avoid touching the 32-bit architectures twice.
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
x32 has always followed the time64 calling conventions of these
syscalls, which required a special hack in compat_get_timespec
aka get_old_timespec32 to continue working.
Since we now have the time64 syscalls, use those explicitly.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
The IPC system call handling is highly inconsistent across architectures,
some use sys_ipc, some use separate calls, and some use both. We also
have some architectures that require passing IPC_64 in the flags, and
others that set it implicitly.
For the addition of a y2038 safe semtimedop() system call, I chose to only
support the separate entry points, but that requires first supporting
the regular ones with their own syscall numbers.
The IPC_64 is now implied by the new semctl/shmctl/msgctl system
calls even on the architectures that require passing it with the ipc()
multiplexer.
I'm not adding the new semtimedop() or semop() on 32-bit architectures,
those will get implemented using the new semtimedop_time64() version
that gets added along with the other time64 calls.
Three 64-bit architectures (powerpc, s390 and sparc) get semtimedop().
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
While in the native case entry into the kernel happens on the trampoline
stack, PV Xen kernels get entered with the current thread stack right
away. Hence source and destination stacks are identical in that case,
and special care is needed.
Other than in sync_regs() the copying done on the INT80 path isn't
NMI / #MC safe, as either of these events occurring in the middle of the
stack copying would clobber data on the (source) stack.
There is similar code in interrupt_entry() and nmi(), but there is no fixup
required because those code paths are unreachable in XEN PV guests.
[ tglx: Sanitized subject, changelog, Fixes tag and stable mail address. Sigh ]
Fixes: 7f2590a110 ("x86/entry/64: Use a per-CPU trampoline stack for IDT entries")
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Peter Anvin <hpa@zytor.com>
Cc: xen-devel@lists.xenproject.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/5C3E1128020000780020DFAD@prv1-mh.provo.novell.com
Currently, CONFIG_JUMP_LABEL just means "I _want_ to use jump label".
The jump label is controlled by HAVE_JUMP_LABEL, which is defined
like this:
#if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL)
# define HAVE_JUMP_LABEL
#endif
We can improve this by testing 'asm goto' support in Kconfig, then
make JUMP_LABEL depend on CC_HAS_ASM_GOTO.
Ugly #ifdef HAVE_JUMP_LABEL will go away, and CONFIG_JUMP_LABEL will
match to the real kernel capability.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument
of the user address range verification function since we got rid of the
old racy i386-only code to walk page tables by hand.
It existed because the original 80386 would not honor the write protect
bit when in kernel mode, so you had to do COW by hand before doing any
user access. But we haven't supported that in a long time, and these
days the 'type' argument is a purely historical artifact.
A discussion about extending 'user_access_begin()' to do the range
checking resulted this patch, because there is no way we're going to
move the old VERIFY_xyz interface to that model. And it's best done at
the end of the merge window when I've done most of my merges, so let's
just get this done once and for all.
This patch was mostly done with a sed-script, with manual fix-ups for
the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form.
There were a couple of notable cases:
- csky still had the old "verify_area()" name as an alias.
- the iter_iov code had magical hardcoded knowledge of the actual
values of VERIFY_{READ,WRITE} (not that they mattered, since nothing
really used it)
- microblaze used the type argument for a debug printout
but other than those oddities this should be a total no-op patch.
I tried to fix up all architectures, did fairly extensive grepping for
access_ok() uses, and the changes are trivial, but I may have missed
something. Any missed conversion should be trivially fixable, though.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull x86 mm updates from Ingo Molnar:
"The main changes in this cycle were:
- Update and clean up x86 fault handling, by Andy Lutomirski.
- Drop usage of __flush_tlb_all() in kernel_physical_mapping_init()
and related fallout, by Dan Williams.
- CPA cleanups and reorganization by Peter Zijlstra: simplify the
flow and remove a few warts.
- Other misc cleanups"
* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (29 commits)
x86/mm/dump_pagetables: Use DEFINE_SHOW_ATTRIBUTE()
x86/mm/cpa: Rename @addrinarray to @numpages
x86/mm/cpa: Better use CLFLUSHOPT
x86/mm/cpa: Fold cpa_flush_range() and cpa_flush_array() into a single cpa_flush() function
x86/mm/cpa: Make cpa_data::numpages invariant
x86/mm/cpa: Optimize cpa_flush_array() TLB invalidation
x86/mm/cpa: Simplify the code after making cpa->vaddr invariant
x86/mm/cpa: Make cpa_data::vaddr invariant
x86/mm/cpa: Add __cpa_addr() helper
x86/mm/cpa: Add ARRAY and PAGES_ARRAY selftests
x86/mm: Drop usage of __flush_tlb_all() in kernel_physical_mapping_init()
x86/mm: Validate kernel_physical_mapping_init() PTE population
generic/pgtable: Introduce set_pte_safe()
generic/pgtable: Introduce {p4d,pgd}_same()
generic/pgtable: Make {pmd, pud}_same() unconditionally available
x86/fault: Clean up the page fault oops decoder a bit
x86/fault: Decode page fault OOPSes better
x86/vsyscall/64: Use X86_PF constants in the simulated #PF error code
x86/oops: Show the correct CS value in show_regs()
x86/fault: Don't try to recover from an implicit supervisor access
...
Pull x86 asm updates from Ingo Molnar:
"Two changes:
- Remove (some) remnants of the vDSO's fake section table mechanism
that were left behind when the vDSO build process reverted to using
"objdump -S" to strip the userspace image.
- Remove hardcoded POPCNT mnemonics now that the minimum binutils
version supports the symbolic form"
* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/vdso: Remove a stale/misleading comment from the linker script
x86/vdso: Remove obsolete "fake section table" reservation
x86: Use POPCNT mnemonics in arch_hweight.h
Pull x86 fixes from Ingo Molnar:
"The biggest part is a series of reverts for the macro based GCC
inlining workarounds. It caused regressions in distro build and other
kernel tooling environments, and the GCC project was very receptive to
fixing the underlying inliner weaknesses - so as time ran out we
decided to do a reasonably straightforward revert of the patches. The
plan is to rely on the 'asm inline' GCC 9 feature, which might be
backported to GCC 8 and could thus become reasonably widely available
on modern distros.
Other than those reverts, there's misc fixes from all around the
place.
I wish our final x86 pull request for v4.20 was smaller..."
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
Revert "kbuild/Makefile: Prepare for using macros in inline assembly code to work around asm() related GCC inlining bugs"
Revert "x86/objtool: Use asm macros to work around GCC inlining bugs"
Revert "x86/refcount: Work around GCC inlining bug"
Revert "x86/alternatives: Macrofy lock prefixes to work around GCC inlining bugs"
Revert "x86/bug: Macrofy the BUG table section handling, to work around GCC inlining bugs"
Revert "x86/paravirt: Work around GCC inlining bugs when compiling paravirt ops"
Revert "x86/extable: Macrofy inline assembly code to work around GCC inlining bugs"
Revert "x86/cpufeature: Macrofy inline assembly code to work around GCC inlining bugs"
Revert "x86/jump-labels: Macrofy inline assembly code to work around GCC inlining bugs"
x86/mtrr: Don't copy uninitialized gentry fields back to userspace
x86/fsgsbase/64: Fix the base write helper functions
x86/mm/cpa: Fix cpa_flush_array() TLB invalidation
x86/vdso: Pass --eh-frame-hdr to the linker
x86/mm: Fix decoy address handling vs 32-bit builds
x86/intel_rdt: Ensure a CPU remains online for the region's pseudo-locking sequence
x86/dump_pagetables: Fix LDT remap address marker
x86/mm: Fix guard hole handling
This reverts commit 5bdcd510c2.
The macro based workarounds for GCC's inlining bugs caused regressions: distcc
and other distro build setups broke, and the fixes are not easy nor will they
solve regressions on already existing installations.
So we are reverting this patch and the 8 followup patches.
What makes this revert easier is that GCC9 will likely include the new 'asm inline'
syntax that makes inlining of assembly blocks a lot more robust.
This is a superior method to any macro based hackeries - and might even be
backported to GCC8, which would make all modern distros get the inlining
fixes as well.
Many thanks to Masahiro Yamada and others for helping sort out these problems.
Reported-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Borislav Petkov <bp@alien8.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Juergen Gross <jgross@suse.com>
Cc: Richard Biener <rguenther@suse.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: Segher Boessenkool <segher@kernel.crashing.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Nadav Amit <namit@vmware.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Commit
379d98ddf4 ("x86: vdso: Use $LD instead of $CC to link")
accidentally broke unwinding from userspace, because ld would strip the
.eh_frame sections when linking.
Originally, the compiler would implicitly add --eh-frame-hdr when
invoking the linker, but when this Makefile was converted from invoking
ld via the compiler, to invoking it directly (like vmlinux does),
the flag was missed. (The EH_FRAME section is important for the VDSO
shared libraries, but not for vmlinux.)
Fix the problem by explicitly specifying --eh-frame-hdr, which restores
parity with the old method.
See relevant bug reports for additional info:
https://bugzilla.kernel.org/show_bug.cgi?id=201741https://bugzilla.redhat.com/show_bug.cgi?id=1659295
Fixes: 379d98ddf4 ("x86: vdso: Use $LD instead of $CC to link")
Reported-by: Florian Weimer <fweimer@redhat.com>
Reported-by: Carlos O'Donell <carlos@redhat.com>
Reported-by: "H. J. Lu" <hjl.tools@gmail.com>
Signed-off-by: Alistair Strachan <astrachan@google.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Tested-by: Laura Abbott <labbott@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Carlos O'Donell <carlos@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: kernel-team@android.com
Cc: Laura Abbott <labbott@redhat.com>
Cc: stable <stable@vger.kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: X86 ML <x86@kernel.org>
Link: https://lkml.kernel.org/r/20181214223637.35954-1-astrachan@google.com
Pull x86 fixes from Ingo Molnar:
"Three fixes: a boot parameter re-(re-)fix, a retpoline build artifact
fix and an LLVM workaround"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/vdso: Drop implicit common-page-size linker flag
x86/build: Fix compiler support check for CONFIG_RETPOLINE
x86/boot: Clear RSDP address in boot_params for broken loaders
GNU linker's -z common-page-size's default value is based on the target
architecture. arch/x86/entry/vdso/Makefile sets it to the architecture
default, which is implicit and redundant. Drop it.
Fixes: 2aae950b21 ("x86_64: Add vDSO for x86-64 with gettimeofday/clock_gettime/getcpu")
Reported-by: Dmitry Golovin <dima@golovin.in>
Reported-by: Bill Wendling <morbo@google.com>
Suggested-by: Dmitry Golovin <dima@golovin.in>
Suggested-by: Rui Ueyama <ruiu@google.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Fangrui Song <maskray@google.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20181206191231.192355-1-ndesaulniers@google.com
Link: https://bugs.llvm.org/show_bug.cgi?id=38774
Link: https://github.com/ClangBuiltLinux/linux/issues/31
These interrupt functions are already non-attachable by kprobes.
Blacklist them explicitly so that they can show up in
/sys/kernel/debug/kprobes/blacklist and tools like BCC can use this
additional information.
Signed-off-by: Andrea Righi <righi.andrea@gmail.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: David S. Miller <davem@davemloft.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yonghong Song <yhs@fb.com>
Link: http://lkml.kernel.org/r/20181206095648.GA8249@Dell
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Once upon a time, vdso2c aggressively stripped data from the vDSO
image when generating the final userspace image. This included
stripping the .altinstructions and .altinstr_replacement sections.
Eventually, the stripping process reverted to "objdump -S" and no
longer removed the aforementioned sections, but the comment remained.
Keeping the .alt* sections at the end of the PT_LOAD segment is no
longer necessary, but there's no harm in doing so and it's a helpful
reminder that they don't need to be included in the final vDSO image,
i.e. someone may want to take another stab at zapping/stripping the
unneeded sections.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: da861e18ec ("x86, vdso: Get rid of the fake section mechanism")
Link: http://lkml.kernel.org/r/20181204212600.28090-3-sean.j.christopherson@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
At one point the vDSO image was manually stripped down by vdso2c in an
attempt to minimize the size of the image mapped into userspace. Part
of that stripping process involved building a fake section table so as
not to break userspace processes that parse the section table. Memory
for the fake section table was reserved in the .rodata section so that
vdso2c could simply copy the entire PT_LOAD segment into the userspace
image after building the fake table.
Eventually, the entire fake section table approach was dropped in favor
of stripping the vdso "the old fashioned way", i.e. via objdump -S.
But, the reservation in .rodata for the fake table was left behind.
Remove the reserveration along with a few other related defines and
section entries.
Removing the fake section table placeholder zaps a whopping 0x340 bytes
from the 64-bit vDSO image, which drops the current image's size to
under 4k, i.e. reduces the effective size of the userspace vDSO mapping
by a full page.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: da861e18ec ("x86, vdso: Get rid of the fake section mechanism")
Link: http://lkml.kernel.org/r/20181204212600.28090-2-sean.j.christopherson@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Go over arch/x86/ and fix common typos in comments,
and a typo in an actual function argument name.
No change in functionality intended.
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Rather than hardcoding 6 with a comment, use the defined constants.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/e023f20352b0d05a8b0205629897917262d2ad68.1542841400.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
- Introduces the stackleak gcc plugin ported from grsecurity by Alexander
Popov, with x86 and arm64 support.
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Merge tag 'stackleak-v4.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull stackleak gcc plugin from Kees Cook:
"Please pull this new GCC plugin, stackleak, for v4.20-rc1. This plugin
was ported from grsecurity by Alexander Popov. It provides efficient
stack content poisoning at syscall exit. This creates a defense
against at least two classes of flaws:
- Uninitialized stack usage. (We continue to work on improving the
compiler to do this in other ways: e.g. unconditional zero init was
proposed to GCC and Clang, and more plugin work has started too).
- Stack content exposure. By greatly reducing the lifetime of valid
stack contents, exposures via either direct read bugs or unknown
cache side-channels become much more difficult to exploit. This
complements the existing buddy and heap poisoning options, but
provides the coverage for stacks.
The x86 hooks are included in this series (which have been reviewed by
Ingo, Dave Hansen, and Thomas Gleixner). The arm64 hooks have already
been merged through the arm64 tree (written by Laura Abbott and
reviewed by Mark Rutland and Will Deacon).
With VLAs having been removed this release, there is no need for
alloca() protection, so it has been removed from the plugin"
* tag 'stackleak-v4.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
arm64: Drop unneeded stackleak_check_alloca()
stackleak: Allow runtime disabling of kernel stack erasing
doc: self-protection: Add information about STACKLEAK feature
fs/proc: Show STACKLEAK metrics in the /proc file system
lkdtm: Add a test for STACKLEAK
gcc-plugins: Add STACKLEAK plugin for tracking the kernel stack
x86/entry: Add STACKLEAK erasing the kernel stack at the end of syscalls
Return vm_fault_t codes directly from the appropriate mm routines instead
of converting from errnos ourselves. Fixes a minor bug where we'd return
SIGBUS instead of the correct OOM code if we ran out of memory allocating
page tables.
Link: http://lkml.kernel.org/r/20180828145728.11873-5-willy@infradead.org
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull siginfo updates from Eric Biederman:
"I have been slowly sorting out siginfo and this is the culmination of
that work.
The primary result is in several ways the signal infrastructure has
been made less error prone. The code has been updated so that manually
specifying SEND_SIG_FORCED is never necessary. The conversion to the
new siginfo sending functions is now complete, which makes it
difficult to send a signal without filling in the proper siginfo
fields.
At the tail end of the patchset comes the optimization of decreasing
the size of struct siginfo in the kernel from 128 bytes to about 48
bytes on 64bit. The fundamental observation that enables this is by
definition none of the known ways to use struct siginfo uses the extra
bytes.
This comes at the cost of a small user space observable difference.
For the rare case of siginfo being injected into the kernel only what
can be copied into kernel_siginfo is delivered to the destination, the
rest of the bytes are set to 0. For cases where the signal and the
si_code are known this is safe, because we know those bytes are not
used. For cases where the signal and si_code combination is unknown
the bits that won't fit into struct kernel_siginfo are tested to
verify they are zero, and the send fails if they are not.
I made an extensive search through userspace code and I could not find
anything that would break because of the above change. If it turns out
I did break something it will take just the revert of a single change
to restore kernel_siginfo to the same size as userspace siginfo.
Testing did reveal dependencies on preferring the signo passed to
sigqueueinfo over si->signo, so bit the bullet and added the
complexity necessary to handle that case.
Testing also revealed bad things can happen if a negative signal
number is passed into the system calls. Something no sane application
will do but something a malicious program or a fuzzer might do. So I
have fixed the code that performs the bounds checks to ensure negative
signal numbers are handled"
* 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (80 commits)
signal: Guard against negative signal numbers in copy_siginfo_from_user32
signal: Guard against negative signal numbers in copy_siginfo_from_user
signal: In sigqueueinfo prefer sig not si_signo
signal: Use a smaller struct siginfo in the kernel
signal: Distinguish between kernel_siginfo and siginfo
signal: Introduce copy_siginfo_from_user and use it's return value
signal: Remove the need for __ARCH_SI_PREABLE_SIZE and SI_PAD_SIZE
signal: Fail sigqueueinfo if si_signo != sig
signal/sparc: Move EMT_TAGOVF into the generic siginfo.h
signal/unicore32: Use force_sig_fault where appropriate
signal/unicore32: Generate siginfo in ucs32_notify_die
signal/unicore32: Use send_sig_fault where appropriate
signal/arc: Use force_sig_fault where appropriate
signal/arc: Push siginfo generation into unhandled_exception
signal/ia64: Use force_sig_fault where appropriate
signal/ia64: Use the force_sig(SIGSEGV,...) in ia64_rt_sigreturn
signal/ia64: Use the generic force_sigsegv in setup_frame
signal/arm/kvm: Use send_sig_mceerr
signal/arm: Use send_sig_fault where appropriate
signal/arm: Use force_sig_fault where appropriate
...
Pull x86 vdso updates from Ingo Molnar:
"Two main changes:
- Cleanups, simplifications and CLOCK_TAI support (Thomas Gleixner)
- Improve code generation (Andy Lutomirski)"
* 'x86-vdso-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/vdso: Rearrange do_hres() to improve code generation
x86/vdso: Document vgtod_ts better
x86/vdso: Remove "memory" clobbers in the vDSO syscall fallbacks
x66/vdso: Add CLOCK_TAI support
x86/vdso: Move cycle_last handling into the caller
x86/vdso: Simplify the invalid vclock case
x86/vdso: Replace the clockid switch case
x86/vdso: Collapse coarse functions
x86/vdso: Collapse high resolution functions
x86/vdso: Introduce and use vgtod_ts
x86/vdso: Use unsigned int consistently for vsyscall_gtod_data:: Seq
x86/vdso: Enforce 64bit clocksource
x86/time: Implement clocksource_arch_init()
clocksource: Provide clocksource_arch_init()
Pull x86 pti updates from Ingo Molnar:
"The main changes:
- Make the IBPB barrier more strict and add STIBP support (Jiri
Kosina)
- Micro-optimize and clean up the entry code (Andy Lutomirski)
- ... plus misc other fixes"
* 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/speculation: Propagate information about RSB filling mitigation to sysfs
x86/speculation: Enable cross-hyperthread spectre v2 STIBP mitigation
x86/speculation: Apply IBPB more strictly to avoid cross-process data leak
x86/speculation: Add RETPOLINE_AMD support to the inline asm CALL_NOSPEC variant
x86/CPU: Fix unused variable warning when !CONFIG_IA32_EMULATION
x86/pti/64: Remove the SYSCALL64 entry trampoline
x86/entry/64: Use the TSS sp2 slot for SYSCALL/SYSRET scratch space
x86/entry/64: Document idtentry
Pull x86 paravirt updates from Ingo Molnar:
"Two main changes:
- Remove no longer used parts of the paravirt infrastructure and put
large quantities of paravirt ops under a new config option
PARAVIRT_XXL=y, which is selected by XEN_PV only. (Joergen Gross)
- Enable PV spinlocks on Hyperv (Yi Sun)"
* 'x86-paravirt-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/hyperv: Enable PV qspinlock for Hyper-V
x86/hyperv: Add GUEST_IDLE_MSR support
x86/paravirt: Clean up native_patch()
x86/paravirt: Prevent redefinition of SAVE_FLAGS macro
x86/xen: Make xen_reservation_lock static
x86/paravirt: Remove unneeded mmu related paravirt ops bits
x86/paravirt: Move the Xen-only pv_mmu_ops under the PARAVIRT_XXL umbrella
x86/paravirt: Move the pv_irq_ops under the PARAVIRT_XXL umbrella
x86/paravirt: Move the Xen-only pv_cpu_ops under the PARAVIRT_XXL umbrella
x86/paravirt: Move items in pv_info under PARAVIRT_XXL umbrella
x86/paravirt: Introduce new config option PARAVIRT_XXL
x86/paravirt: Remove unused paravirt bits
x86/paravirt: Use a single ops structure
x86/paravirt: Remove clobbers from struct paravirt_patch_site
x86/paravirt: Remove clobbers parameter from paravirt patch functions
x86/paravirt: Make paravirt_patch_call() and paravirt_patch_jmp() static
x86/xen: Add SPDX identifier in arch/x86/xen files
x86/xen: Link platform-pci-unplug.o only if CONFIG_XEN_PVHVM
x86/xen: Move pv specific parts of arch/x86/xen/mmu.c to mmu_pv.c
x86/xen: Move pv irq related functions under CONFIG_XEN_PV umbrella
Pull x86 asm updates from Ingo Molnar:
"The main changes in this cycle were the fsgsbase related preparatory
patches from Chang S. Bae - but there's also an optimized
memcpy_flushcache() and a cleanup for the __cmpxchg_double() assembly
glue"
* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/fsgsbase/64: Clean up various details
x86/segments: Introduce the 'CPUNODE' naming to better document the segment limit CPU/node NR trick
x86/vdso: Initialize the CPU/node NR segment descriptor earlier
x86/vdso: Introduce helper functions for CPU and node number
x86/segments/64: Rename the GDT PER_CPU entry to CPU_NUMBER
x86/fsgsbase/64: Factor out FS/GS segment loading from __switch_to()
x86/fsgsbase/64: Convert the ELF core dump code to the new FSGSBASE helpers
x86/fsgsbase/64: Make ptrace use the new FS/GS base helpers
x86/fsgsbase/64: Introduce FS/GS base helper functions
x86/fsgsbase/64: Fix ptrace() to read the FS/GS base accurately
x86/asm: Use CC_SET()/CC_OUT() in __cmpxchg_double()
x86/asm: Optimize memcpy_flushcache()
Pull locking and misc x86 updates from Ingo Molnar:
"Lots of changes in this cycle - in part because locking/core attracted
a number of related x86 low level work which was easier to handle in a
single tree:
- Linux Kernel Memory Consistency Model updates (Alan Stern, Paul E.
McKenney, Andrea Parri)
- lockdep scalability improvements and micro-optimizations (Waiman
Long)
- rwsem improvements (Waiman Long)
- spinlock micro-optimization (Matthew Wilcox)
- qspinlocks: Provide a liveness guarantee (more fairness) on x86.
(Peter Zijlstra)
- Add support for relative references in jump tables on arm64, x86
and s390 to optimize jump labels (Ard Biesheuvel, Heiko Carstens)
- Be a lot less permissive on weird (kernel address) uaccess faults
on x86: BUG() when uaccess helpers fault on kernel addresses (Jann
Horn)
- macrofy x86 asm statements to un-confuse the GCC inliner. (Nadav
Amit)
- ... and a handful of other smaller changes as well"
* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (57 commits)
locking/lockdep: Make global debug_locks* variables read-mostly
locking/lockdep: Fix debug_locks off performance problem
locking/pvqspinlock: Extend node size when pvqspinlock is configured
locking/qspinlock_stat: Count instances of nested lock slowpaths
locking/qspinlock, x86: Provide liveness guarantee
x86/asm: 'Simplify' GEN_*_RMWcc() macros
locking/qspinlock: Rework some comments
locking/qspinlock: Re-order code
locking/lockdep: Remove duplicated 'lock_class_ops' percpu array
x86/defconfig: Enable CONFIG_USB_XHCI_HCD=y
futex: Replace spin_is_locked() with lockdep
locking/lockdep: Make class->ops a percpu counter and move it under CONFIG_DEBUG_LOCKDEP=y
x86/jump-labels: Macrofy inline assembly code to work around GCC inlining bugs
x86/cpufeature: Macrofy inline assembly code to work around GCC inlining bugs
x86/extable: Macrofy inline assembly code to work around GCC inlining bugs
x86/paravirt: Work around GCC inlining bugs when compiling paravirt ops
x86/bug: Macrofy the BUG table section handling, to work around GCC inlining bugs
x86/alternatives: Macrofy lock prefixes to work around GCC inlining bugs
x86/refcount: Work around GCC inlining bug
x86/objtool: Use asm macros to work around GCC inlining bugs
...
Commit:
16561f27f9 ("x86/entry: Add some paranoid entry/exit CR3 handling comments")
... added some comments. This improves them a bit:
- When I first read the new comments, it was unclear to me whether
they were referring to the case where paranoid_entry interrupted
other entry code or where paranoid_entry was itself interrupted.
Clarify it.
- Remove the EBX comment. We no longer use EBX as a SWAPGS
indicator.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/c47daa1888dc2298e7e1d3f82bd76b776ea33393.1539542111.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Even if not on an entry stack, the CS's high bits must be
initialized because they are unconditionally evaluated in
PARANOID_EXIT_TO_KERNEL_MODE.
Failing to do so broke the boot on Galileo Gen2 and IOT2000 boards.
[ bp: Make the commit message tone passive and impartial. ]
Fixes: b92a165df1 ("x86/entry/32: Handle Entry from Kernel-Mode on Entry-Stack")
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Joerg Roedel <jroedel@suse.de>
Acked-by: Joerg Roedel <jroedel@suse.de>
CC: "H. Peter Anvin" <hpa@zytor.com>
CC: Andrea Arcangeli <aarcange@redhat.com>
CC: Andy Lutomirski <luto@kernel.org>
CC: Boris Ostrovsky <boris.ostrovsky@oracle.com>
CC: Brian Gerst <brgerst@gmail.com>
CC: Dave Hansen <dave.hansen@intel.com>
CC: David Laight <David.Laight@aculab.com>
CC: Denys Vlasenko <dvlasenk@redhat.com>
CC: Eduardo Valentin <eduval@amazon.com>
CC: Greg KH <gregkh@linuxfoundation.org>
CC: Ingo Molnar <mingo@kernel.org>
CC: Jiri Kosina <jkosina@suse.cz>
CC: Josh Poimboeuf <jpoimboe@redhat.com>
CC: Juergen Gross <jgross@suse.com>
CC: Linus Torvalds <torvalds@linux-foundation.org>
CC: Peter Zijlstra <peterz@infradead.org>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Will Deacon <will.deacon@arm.com>
CC: aliguori@amazon.com
CC: daniel.gruss@iaik.tugraz.at
CC: hughd@google.com
CC: keescook@google.com
CC: linux-mm <linux-mm@kvack.org>
CC: x86-ml <x86@kernel.org>
Link: http://lkml.kernel.org/r/f271c747-1714-5a5b-a71f-ae189a093b8d@siemens.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Andi Kleen was just asking me about the NMI CR3 handling and why
we restore it unconditionally. I was *sure* we had documented it
well. We did not.
Add some documentation. We have common entry code where the CR3
value is stashed, but three places in two big code paths where we
restore it. I put bulk of the comments in this common path and
then refer to it from the other spots.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: luto@kernel.org
Cc: bp@alien8.de
Cc: "H. Peter Anvin" <hpa@zytor.come
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Link: https://lkml.kernel.org/r/20181012232118.3EAAE77B@viggo.jf.intel.com
So:
- use 'extern' consistently for APIs
- fix weird header guard
- clarify code comments
- reorder APIs by type
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Chang S. Bae <chang.seok.bae@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Markus T Metzger <markus.t.metzger@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Shankar <ravi.v.shankar@intel.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/1537312139-5580-2-git-send-email-chang.seok.bae@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We have a special segment descriptor entry in the GDT, whose sole purpose is to
encode the CPU and node numbers in its limit (size) field. There are user-space
instructions that allow the reading of the limit field, which gives us a really
fast way to read the CPU and node IDs from the vDSO for example.
But the naming of related functionality does not make this clear, at all:
VDSO_CPU_SIZE
VDSO_CPU_MASK
__CPU_NUMBER_SEG
GDT_ENTRY_CPU_NUMBER
vdso_encode_cpu_node
vdso_read_cpu_node
There's a number of problems:
- The 'VDSO_CPU_SIZE' doesn't really make it clear that these are number
of bits, nor does it make it clear which 'CPU' this refers to, i.e.
that this is about a GDT entry whose limit encodes the CPU and node number.
- Furthermore, the 'CPU_NUMBER' naming is actively misleading as well,
because the segment limit encodes not just the CPU number but the
node ID as well ...
So use a better nomenclature all around: name everything related to this trick
as 'CPUNODE', to make it clear that this is something special, and add
_BITS to make it clear that these are number of bits, and propagate this to
every affected name:
VDSO_CPU_SIZE => VDSO_CPUNODE_BITS
VDSO_CPU_MASK => VDSO_CPUNODE_MASK
__CPU_NUMBER_SEG => __CPUNODE_SEG
GDT_ENTRY_CPU_NUMBER => GDT_ENTRY_CPUNODE
vdso_encode_cpu_node => vdso_encode_cpunode
vdso_read_cpu_node => vdso_read_cpunode
This, beyond being less confusing, also makes it easier to grep for all related
functionality:
$ git grep -i cpunode arch/x86
Also, while at it, fix "return is not a function" style sloppiness in vdso_encode_cpunode().
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Chang S. Bae <chang.seok.bae@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Markus T Metzger <markus.t.metzger@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Shankar <ravi.v.shankar@intel.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/1537312139-5580-2-git-send-email-chang.seok.bae@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Currently the CPU/node NR segment descriptor (GDT_ENTRY_CPU_NUMBER) is
initialized relatively late during CPU init, from the vCPU code, which
has a number of disadvantages, such as hotplug CPU notifiers and SMP
cross-calls.
Instead just initialize it much earlier, directly in cpu_init().
This reduces complexity and increases robustness.
[ mingo: Wrote new changelog. ]
Suggested-by: H. Peter Anvin <hpa@zytor.com>
Suggested-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Markus T Metzger <markus.t.metzger@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Shankar <ravi.v.shankar@intel.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1537312139-5580-9-git-send-email-chang.seok.bae@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Clean up the CPU/node number related code a bit, to make it more apparent
how we are encoding/extracting the CPU and node fields from the
segment limit.
No change in functionality intended.
[ mingo: Wrote new changelog. ]
Suggested-by: Andy Lutomirski <luto@kernel.org>
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Markus T Metzger <markus.t.metzger@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Shankar <ravi.v.shankar@intel.com>
Cc: Rik van Riel <riel@surriel.com>
Link: http://lkml.kernel.org/r/1537312139-5580-8-git-send-email-chang.seok.bae@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The old 'per CPU' naming was misleading: 64-bit kernels don't use this
GDT entry for per CPU data, but to store the CPU (and node) ID.
[ mingo: Wrote new changelog. ]
Suggested-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Markus T Metzger <markus.t.metzger@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Shankar <ravi.v.shankar@intel.com>
Cc: Rik van Riel <riel@surriel.com>
Link: http://lkml.kernel.org/r/1537312139-5580-7-git-send-email-chang.seok.bae@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
As described in:
77b0bf55bc67: ("kbuild/Makefile: Prepare for using macros in inline assembly code to work around asm() related GCC inlining bugs")
GCC's inlining heuristics are broken with common asm() patterns used in
kernel code, resulting in the effective disabling of inlining.
The workaround is to set an assembly macro and call it from the inline
assembly block - which is also a minor cleanup for the jump-label code.
As a result the code size is slightly increased, but inlining decisions
are better:
text data bss dec hex filename
18163528 10226300 2957312 31347140 1de51c4 ./vmlinux before
18163608 10227348 2957312 31348268 1de562c ./vmlinux after (+1128)
And functions such as intel_pstate_adjust_policy_max(),
kvm_cpu_accept_dm_intr(), kvm_register_readl() are inlined.
Tested-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Nadav Amit <namit@vmware.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20181005202718.229565-4-namit@vmware.com
Link: https://lore.kernel.org/lkml/20181003213100.189959-11-namit@vmware.com/T/#u
Signed-off-by: Ingo Molnar <mingo@kernel.org>
vgetcyc() is full of barriers, so fetching values out of the vvar
page before vgetcyc() for use after vgetcyc() results in poor code
generation. Put vgetcyc() first to avoid this problem.
Also, pull the tv_sec division into the loop and put all the ts
writes together. The old code wrote ts->tv_sec on each iteration
before the syscall fallback check and then added in the offset
afterwards, which forced the compiler to pointlessly copy base->sec
to ts->tv_sec on each iteration. The new version seems to generate
sensible code.
Saves several cycles. With this patch applied, the result is faster
than before the clock_gettime() rewrite.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/3c05644d010b72216aa286a6d20b5078d5fae5cd.1538762487.git.luto@kernel.org
When a vDSO clock function falls back to the syscall, no special
barriers or ordering is needed, and the syscall fallbacks don't
clobber any memory that is not explicitly listed in the asm
constraints. Remove the "memory" clobber.
This causes minor changes to the generated code, but otherwise has
no obvious performance impact. I think it's nice to have, though,
since it may help the optimizer in the future.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/3a7438f5fb2422ed881683d2ccffd7f987b2dc44.1538689401.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
With the storage array in place it's now trivial to support CLOCK_TAI in
the vdso. Extend the base time storage array and add the update code.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Matt Rickard <matt@softrans.com.au>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: devel@linuxdriverproject.org
Cc: virtualization@lists.linux-foundation.org
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Juergen Gross <jgross@suse.com>
Link: https://lkml.kernel.org/r/20180917130707.823878601@linutronix.de
Dereferencing gtod->cycle_last all over the place and foing the cycles <
last comparison in the vclock read functions generates horrible code. Doing
it at the call site is much better and gains a few cycles both for TSC and
pvclock.
Caveat: This adds the comparison to the hyperv vclock as well, but I have
no way to test that.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Matt Rickard <matt@softrans.com.au>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: devel@linuxdriverproject.org
Cc: virtualization@lists.linux-foundation.org
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Juergen Gross <jgross@suse.com>
Link: https://lkml.kernel.org/r/20180917130707.741440803@linutronix.de
The code flow for the vclocks is convoluted as it requires the vclocks
which can be invalidated separately from the vsyscall_gtod_data sequence to
store the fact in a separate variable. That's inefficient.
Restructure the code so the vclock readout returns cycles and the
conversion to nanoseconds is handled at the call site.
If the clock gets invalidated or vclock is already VCLOCK_NONE, return
U64_MAX as the cycle value, which is invalid for all clocks and leave the
sequence loop immediately in that case by calling the fallback function
directly.
This allows to remove the gettimeofday fallback as it now uses the
clock_gettime() fallback and does the nanoseconds to microseconds
conversion in the same way as it does when the vclock is functional. It
does not make a difference whether the division by 1000 happens in the
kernel fallback or in userspace.
Generates way better code and gains a few cycles back.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Matt Rickard <matt@softrans.com.au>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: devel@linuxdriverproject.org
Cc: virtualization@lists.linux-foundation.org
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Juergen Gross <jgross@suse.com>
Link: https://lkml.kernel.org/r/20180917130707.657928937@linutronix.de
Now that the time getter functions use the clockid as index into the
storage array for the base time access, the switch case can be replaced.
- Check for clockid >= MAX_CLOCKS and for negative clockid (CPU/FD) first
and call the fallback function right away.
- After establishing that clockid is < MAX_CLOCKS, convert the clockid to a
bitmask
- Check for the supported high resolution and coarse functions by anding
the bitmask of supported clocks and check whether a bit is set.
This completely avoids jump tables, reduces the number of conditionals and
makes the VDSO extensible for other clock ids.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Matt Rickard <matt@softrans.com.au>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: devel@linuxdriverproject.org
Cc: virtualization@lists.linux-foundation.org
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Juergen Gross <jgross@suse.com>
Link: https://lkml.kernel.org/r/20180917130707.574315796@linutronix.de
do_realtime_coarse() and do_monotonic_coarse() are now the same except for
the storage array index. Hand the index in as an argument and collapse the
functions.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Matt Rickard <matt@softrans.com.au>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: devel@linuxdriverproject.org
Cc: virtualization@lists.linux-foundation.org
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Juergen Gross <jgross@suse.com>
Link: https://lkml.kernel.org/r/20180917130707.490733779@linutronix.de
do_realtime() and do_monotonic() are now the same except for the storage
array index. Hand the index in as an argument and collapse the functions.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Matt Rickard <matt@softrans.com.au>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: devel@linuxdriverproject.org
Cc: virtualization@lists.linux-foundation.org
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Juergen Gross <jgross@suse.com>
Link: https://lkml.kernel.org/r/20180917130707.407955860@linutronix.de
Thomas Gleixner