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* x86/entry/compat: Keep TS_COMPAT set during signal deliveryAndy Lutomirski2016-02-171-10/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Signal delivery needs to know the sign of an interrupted syscall's return value in order to detect -ERESTART variants. Normally this works independently of bitness because syscalls internally return long. Under ptrace, however, this can break, and syscall_get_error is supposed to sign-extend regs->ax if needed. We were clearing TS_COMPAT too early, though, and this prevented sign extension, which subtly broke syscall restart under ptrace. Reported-by: Robert O'Callahan <robert@ocallahan.org> Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Al Viro <viro@zeniv.linux.org.uk> 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: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Shuah Khan <shuahkh@osg.samsung.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org # 4.3.x- Fixes: c5c46f59e4e7 ("x86/entry: Add new, comprehensible entry and exit handlers written in C") Link: http://lkml.kernel.org/r/cbce3cf545522f64eb37f5478cb59746230db3b5.1455142412.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* x86/syscalls/64: Mark sys_iopl() as using ptregsAndy Lutomirski2016-02-011-1/+1
| | | | | | | | | | | | | | | | | | | | | | sys_iopl() both reads and writes pt_regs->flags. Mark it as using ptregs. This isn't strictly necessary, as pt_regs->flags is available even in the fast path, but this is very lightweight now that we have syscall qualifiers and it could avoid some pain down the road. Reported-and-tested-by: Borislav Petkov <bp@suse.de> Signed-off-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: 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: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/3de0ca692fa8bf414c5e3d7afe3e6195d1a10e1f.1454261517.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* x86/entry/64: Fix fast-path syscall return register stateAndy Lutomirski2016-02-011-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | I was fishing RIP (i.e. RCX) out of pt_regs->cx and RFLAGS (i.e. R11) out of pt_regs->r11. While it usually worked (pt_regs started out with CX == IP and R11 == FLAGS), it was very fragile. In particular, it broke sys_iopl() because sys_iopl() forgot to mark itself as using ptregs. Undo that part of the syscall rework. There was no compelling reason to do it this way. While I'm at it, load RCX and R11 before the other regs to be a little friendlier to the CPU, as they will be the first of the reloaded registers to be used. Reported-and-tested-by: Borislav Petkov <bp@suse.de> Signed-off-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: 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: Thomas Gleixner <tglx@linutronix.de> Fixes: 1e423bff959e x86/entry/64: ("Migrate the 64-bit syscall slow path to C") Link: http://lkml.kernel.org/r/a85f8360c397e48186a9bc3e565ad74307a7b011.1454261517.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* x86/entry/64: Fix an IRQ state error on ptregs-using syscallsAndy Lutomirski2016-02-011-6/+13
| | | | | | | | | | | | | | | | | | | | | I messed up the IRQ state when jumping off the fast path due to invocation of a ptregs-using syscall. This bug shouldn't have had any impact yet, but it would have caused problems with subsequent context tracking cleanups. Reported-and-tested-by: Borislav Petkov <bp@suse.de> Signed-off-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: 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: Thomas Gleixner <tglx@linutronix.de> Fixes: 1e423bff959e x86/entry/64: ("Migrate the 64-bit syscall slow path to C") Link: http://lkml.kernel.org/r/ab92cd365fb7b0a56869e920017790d96610fdca.1454261517.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* x86/vdso: Use static_cpu_has()Borislav Petkov2016-01-301-1/+1
| | | | | | | | | | | | | | | | ... and simplify and speed up a tad. Signed-off-by: Borislav Petkov <bp@suse.de> 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: H. Peter Anvin <hpa@zytor.com> 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/1453842730-28463-10-git-send-email-bp@alien8.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
* x86/cpufeature: Carve out X86_FEATURE_*Borislav Petkov2016-01-305-3/+4
| | | | | | | | | | | | | | | | | | | | | | Move them to a separate header and have the following dependency: x86/cpufeatures.h <- x86/processor.h <- x86/cpufeature.h This makes it easier to use the header in asm code and not include the whole cpufeature.h and add guards for asm. Suggested-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Borislav Petkov <bp@suse.de> 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: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1453842730-28463-5-git-send-email-bp@alien8.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
* x86/entry/64: Migrate the 64-bit syscall slow path to CAndy Lutomirski2016-01-292-78/+65
| | | | | | | | | | | | | | | | | | | | | | | This is more complicated than the 32-bit and compat cases because it preserves an asm fast path for the case where the callee-saved regs aren't needed in pt_regs and no entry or exit work needs to be done. This appears to slow down fastpath syscalls by no more than one cycle on my Skylake laptop. Signed-off-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: Denys Vlasenko <dvlasenk@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> 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/ce2335a4d42dc164b24132ee5e8c7716061f947b.1454022279.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* x86/entry/64: Stop using int_ret_from_sys_call in ret_from_forkAndy Lutomirski2016-01-291-16/+19
| | | | | | | | | | | | | | | | | | | ret_from_fork is now open-coded and is no longer tangled up with the syscall code. This isn't so bad -- this adds very little code, and IMO the result is much easier to understand. Signed-off-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: Denys Vlasenko <dvlasenk@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> 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/a0747e2a5e47084655a1e96351c545b755c41fa7.1454022279.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* x86/entry/64: Call all native slow-path syscalls with full pt-regsAndy Lutomirski2016-01-292-87/+10
| | | | | | | | | | | | | | | | | | | | | | | This removes all of the remaining asm syscall stubs except for stub_ptregs_64. Entries in the main syscall table are now all callable from C. The resulting asm is every bit as ridiculous as it looks. The next few patches will clean it up. This patch is here to let reviewers rest their brains and for bisection. Signed-off-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: Denys Vlasenko <dvlasenk@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> 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/a6b3801be0d505d50aefabda02d3b93efbfc9c73.1454022279.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* x86/entry/64: Always run ptregs-using syscalls on the slow pathAndy Lutomirski2016-01-293-24/+55
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 64-bit syscalls currently have an optimization in which they are called with partial pt_regs. A small handful require full pt_regs. In the 32-bit and compat cases, I cleaned this up by forcing full pt_regs for all syscalls. The performance hit doesn't really matter as the affected system calls are fundamentally heavy and this is the 32-bit compat case. I want to clean up the 64-bit case as well, but I don't want to hurt fast path performance. To do that, I want to force the syscalls that use pt_regs onto the slow path. This will enable us to make slow path syscalls be real ABI-compliant C functions. Use the new syscall entry qualification machinery for this. 'stub_clone' is now 'stub_clone/ptregs'. The next patch will eliminate the stubs, and we'll just have 'sys_clone/ptregs'. As of this patch, two-phase entry tracing is no longer used. It has served its purpose (namely a huge speedup on some workloads prior to more general opportunistic SYSRET support), and once the dust settles I'll send patches to back it out. The implementation is heavily based on a patch from Brian Gerst: http://lkml.kernel.org/g/1449666173-15366-1-git-send-email-brgerst@gmail.com Originally-From: Brian Gerst <brgerst@gmail.com> Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Frédéric Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/b9beda88460bcefec6e7d792bd44eca9b760b0c4.1454022279.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* x86/syscalls: Add syscall entry qualifiersAndy Lutomirski2016-01-293-7/+20
| | | | | | | | | | | | | | | | | | | | | | This will let us specify something like 'sys_xyz/foo' instead of 'sys_xyz' in the syscall table, where the 'foo' qualifier conveys some extra information to the C code. The intent is to allow things like sys_execve/ptregs to indicate that sys_execve() touches pt_regs. Signed-off-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: Denys Vlasenko <dvlasenk@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> 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/2de06e33dce62556b3ec662006fcb295504e296e.1454022279.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* x86/syscalls: Move compat syscall entry handling into syscalltbl.shAndy Lutomirski2016-01-293-14/+22
| | | | | | | | | | | | | | | | | | | | | | | | Rather than duplicating the compat entry handling in all consumers of syscalls_BITS.h, handle it directly in syscalltbl.sh. Now we generate entries in syscalls_32.h like: __SYSCALL_I386(5, sys_open) __SYSCALL_I386(5, compat_sys_open) and all of its consumers implicitly get the right entry point. Signed-off-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: Denys Vlasenko <dvlasenk@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> 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/b7c2b501dc0e6e43050e916b95807c3e2e16e9bb.1454022279.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* x86/syscalls: Remove __SYSCALL_COMMON and __SYSCALL_X32Andy Lutomirski2016-01-292-9/+16
| | | | | | | | | | | | | | | | | | | The common/64/x32 distinction has no effect other than determining which kernels actually support the syscall. Move the logic into syscalltbl.sh. Signed-off-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: Denys Vlasenko <dvlasenk@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> 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/58d4a95f40e43b894f93288b4a3633963d0ee22e.1454022279.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* x86/syscalls: Refactor syscalltbl.shAndy Lutomirski2016-01-291-5/+13
| | | | | | | | | | | | | | | | | This splits out the code to emit a syscall line. Signed-off-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: Denys Vlasenko <dvlasenk@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> 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/1bfcbba991f5cfaa9291ff950a593daa972a205f.1454022279.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* Merge tag 'v4.5-rc1' into x86/asm, to refresh the branch before merging new ↵Ingo Molnar2016-01-294-6/+9
|\ | | | | | | | | | | changes Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * UBSAN: run-time undefined behavior sanity checkerAndrey Ryabinin2016-01-211-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | UBSAN uses compile-time instrumentation to catch undefined behavior (UB). Compiler inserts code that perform certain kinds of checks before operations that could cause UB. If check fails (i.e. UB detected) __ubsan_handle_* function called to print error message. So the most of the work is done by compiler. This patch just implements ubsan handlers printing errors. GCC has this capability since 4.9.x [1] (see -fsanitize=undefined option and its suboptions). However GCC 5.x has more checkers implemented [2]. Article [3] has a bit more details about UBSAN in the GCC. [1] - https://gcc.gnu.org/onlinedocs/gcc-4.9.0/gcc/Debugging-Options.html [2] - https://gcc.gnu.org/onlinedocs/gcc/Debugging-Options.html [3] - http://developerblog.redhat.com/2014/10/16/gcc-undefined-behavior-sanitizer-ubsan/ Issues which UBSAN has found thus far are: Found bugs: * out-of-bounds access - 97840cb67ff5 ("netfilter: nfnetlink: fix insufficient validation in nfnetlink_bind") undefined shifts: * d48458d4a768 ("jbd2: use a better hash function for the revoke table") * 10632008b9e1 ("clockevents: Prevent shift out of bounds") * 'x << -1' shift in ext4 - http://lkml.kernel.org/r/<5444EF21.8020501@samsung.com> * undefined rol32(0) - http://lkml.kernel.org/r/<1449198241-20654-1-git-send-email-sasha.levin@oracle.com> * undefined dirty_ratelimit calculation - http://lkml.kernel.org/r/<566594E2.3050306@odin.com> * undefined roundown_pow_of_two(0) - http://lkml.kernel.org/r/<1449156616-11474-1-git-send-email-sasha.levin@oracle.com> * [WONTFIX] undefined shift in __bpf_prog_run - http://lkml.kernel.org/r/<CACT4Y+ZxoR3UjLgcNdUm4fECLMx2VdtfrENMtRRCdgHB2n0bJA@mail.gmail.com> WONTFIX here because it should be fixed in bpf program, not in kernel. signed overflows: * 32a8df4e0b33f ("sched: Fix odd values in effective_load() calculations") * mul overflow in ntp - http://lkml.kernel.org/r/<1449175608-1146-1-git-send-email-sasha.levin@oracle.com> * incorrect conversion into rtc_time in rtc_time64_to_tm() - http://lkml.kernel.org/r/<1449187944-11730-1-git-send-email-sasha.levin@oracle.com> * unvalidated timespec in io_getevents() - http://lkml.kernel.org/r/<CACT4Y+bBxVYLQ6LtOKrKtnLthqLHcw-BMp3aqP3mjdAvr9FULQ@mail.gmail.com> * [NOTABUG] signed overflow in ktime_add_safe() - http://lkml.kernel.org/r/<CACT4Y+aJ4muRnWxsUe1CMnA6P8nooO33kwG-c8YZg=0Xc8rJqw@mail.gmail.com> [akpm@linux-foundation.org: fix unused local warning] [akpm@linux-foundation.org: fix __int128 build woes] Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Michal Marek <mmarek@suse.cz> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Yury Gribov <y.gribov@samsung.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Kostya Serebryany <kcc@google.com> Cc: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * Merge branch 'x86-urgent-for-linus' of ↵Linus Torvalds2016-01-141-6/+6
| |\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 fixes from Ingo Molnar: "Misc changes: - fix lguest bug - fix /proc/meminfo output on certain configs - fix pvclock bug - fix reboot on certain iMacs by adding new reboot quirk - fix bootup crash - fix FPU boot line option parsing - add more x86 self-tests - small cleanups, documentation improvements, etc" * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/cpu/amd: Remove an unneeded condition in srat_detect_node() x86/vdso/pvclock: Protect STABLE check with the seqcount x86/mm: Improve switch_mm() barrier comments selftests/x86: Test __kernel_sigreturn and __kernel_rt_sigreturn x86/reboot/quirks: Add iMac10,1 to pci_reboot_dmi_table[] lguest: Map switcher text R/O x86/boot: Hide local labels in verify_cpu() x86/fpu: Disable AVX when eagerfpu is off x86/fpu: Disable MPX when eagerfpu is off x86/fpu: Disable XGETBV1 when no XSAVE x86/fpu: Fix early FPU command-line parsing x86/mm: Use PAGE_ALIGNED instead of IS_ALIGNED selftests/x86: Disable the ldt_gdt_64 test for now x86/mm/pat: Make split_page_count() check for empty levels to fix /proc/meminfo output x86/boot: Double BOOT_HEAP_SIZE to 64KB x86/mm: Add barriers and document switch_mm()-vs-flush synchronization
| | * x86/vdso/pvclock: Protect STABLE check with the seqcountAndy Lutomirski2016-01-131-6/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If the clock becomes unstable while we're reading it, we need to bail. We can do this by simply moving the check into the seqcount loop. Reported-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Alexander Graf <agraf@suse.de> 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: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Radim Krcmar <rkrcmar@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/755dcedb17269e1d7ce12a9a713dea303835137e.1451949191.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | Merge branch 'work.copy_file_range' of ↵Linus Torvalds2016-01-132-0/+2
| |\ \ | | |/ | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs copy_file_range updates from Al Viro: "Several series around copy_file_range/CLONE" * 'work.copy_file_range' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: btrfs: use new dedupe data function pointer vfs: hoist the btrfs deduplication ioctl to the vfs vfs: wire up compat ioctl for CLONE/CLONE_RANGE cifs: avoid unused variable and label nfsd: implement the NFSv4.2 CLONE operation nfsd: Pass filehandle to nfs4_preprocess_stateid_op() vfs: pull btrfs clone API to vfs layer locks: new locks_mandatory_area calling convention vfs: Add vfs_copy_file_range() support for pagecache copies btrfs: add .copy_file_range file operation x86: add sys_copy_file_range to syscall tables vfs: add copy_file_range syscall and vfs helper
| | * x86: add sys_copy_file_range to syscall tablesZach Brown2015-12-012-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add sys_copy_file_range to the x86 syscall tables. Signed-off-by: Zach Brown <zab@redhat.com> [Anna Schumaker: Update syscall number in syscall_32.tbl] Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | | x86/asm/entry: Remove unused SAVE_ALL/RESTORE_ALL macros for !CONFIG_x86_64Alexander Kuleshov2016-01-191-31/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | SAVE_ALL and RESTORE_ALL macros for !CONFIG_X86_64 were introduced in commit: 1a338ac32 commit ('sched, x86: Optimize the preempt_schedule() call') ... and were used in the ___preempt_schedule() and ___preempt_schedule_context() functions from the arch/x86/kernel/preempt.S. But the arch/x86/kernel/preempt.S file was removed in the following commit: 0ad6e3c5 commit ('x86: Speed up ___preempt_schedule*() by using THUNK helpers') The ___preempt_schedule()/___preempt_schedule_context() functions were reimplemeted and do not use SAVE_ALL/RESTORE_ALL anymore. These macros have no users anymore, so we can remove them. Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com> Acked-by: Andy Lutomirski <luto@amacapital.net> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.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: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1453126394-13717-1-git-send-email-kuleshovmail@gmail.com [ Improved the changelog. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | x86/vdso: Disallow vvar access to vclock IO for never-used vclocksAndy Lutomirski2016-01-122-3/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It makes me uncomfortable that even modern systems grant every process direct read access to the HPET. While fixing this for real without regressing anything is a mess (unmapping the HPET is tricky because we don't adequately track all the mappings), we can do almost as well by tracking which vclocks have ever been used and only allowing pages associated with used vclocks to be faulted in. This will cause rogue programs that try to peek at the HPET to get SIGBUS instead on most systems. We can't restrict faults to vclock pages that are associated with the currently selected vclock due to a race: a process could start to access the HPET for the first time and race against a switch away from the HPET as the current clocksource. We can't segfault the process trying to peek at the HPET in this case, even though the process isn't going to do anything useful with the data. Signed-off-by: Andy Lutomirski <luto@kernel.org> Reviewed-by: Kees Cook <keescook@chromium.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/e79d06295625c02512277737ab55085a498ac5d8.1451446564.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | x86/vdso: Use ->fault() instead of remap_pfn_range() for the vvar mappingAndy Lutomirski2016-01-121-40/+57
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is IMO much less ugly, and it also opens the door to disallowing unprivileged userspace HPET access on systems with usable TSCs. Signed-off-by: Andy Lutomirski <luto@kernel.org> Reviewed-by: Kees Cook <keescook@chromium.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/c19c2909e5ee3c3d8742f916586676bb7c40345f.1451446564.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | x86/vdso: Use .fault for the vDSO text mappingAndy Lutomirski2016-01-122-14/+19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The old scheme for mapping the vDSO text is rather complicated. vdso2c generates a struct vm_special_mapping and a blank .pages array of the correct size for each vdso image. Init code in vdso/vma.c populates the .pages array for each vDSO image, and the mapping code selects the appropriate struct vm_special_mapping. With .fault, we can use a less roundabout approach: vdso_fault() just returns the appropriate page for the selected vDSO image. Signed-off-by: Andy Lutomirski <luto@kernel.org> Reviewed-by: Kees Cook <keescook@chromium.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/f886954c186bafd74e1b967c8931d852ae199aa2.1451446564.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | x86/vdso: Track each mm's loaded vDSO image as well as its baseAndy Lutomirski2016-01-121-0/+1
|/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As we start to do more intelligent things with the vDSO at runtime (as opposed to just at mm initialization time), we'll need to know which vDSO is in use. In principle, we could guess based on the mm type, but that's over-complicated and error-prone. Instead, just track it in the mmu context. Signed-off-by: Andy Lutomirski <luto@kernel.org> Reviewed-by: Kees Cook <keescook@chromium.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/c99ac48681bad709ca7ad5ee899d9042a3af6b00.1451446564.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | Merge branch 'x86-asm-for-linus' of ↵Linus Torvalds2016-01-128-104/+118
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 asm updates from Ingo Molnar: "The main changes in this cycle were: - vDSO and asm entry improvements (Andy Lutomirski) - Xen paravirt entry enhancements (Boris Ostrovsky) - asm entry labels enhancement (Borislav Petkov) - and other misc changes (Thomas Gleixner, me)" * 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/vsdo: Fix build on PARAVIRT_CLOCK=y, KVM_GUEST=n Revert "x86/kvm: On KVM re-enable (e.g. after suspend), update clocks" x86/entry/64_compat: Make labels local x86/platform/uv: Include clocksource.h for clocksource_touch_watchdog() x86/vdso: Enable vdso pvclock access on all vdso variants x86/vdso: Remove pvclock fixmap machinery x86/vdso: Get pvclock data from the vvar VMA instead of the fixmap x86, vdso, pvclock: Simplify and speed up the vdso pvclock reader x86/kvm: On KVM re-enable (e.g. after suspend), update clocks x86/entry/64: Bypass enter_from_user_mode on non-context-tracking boots x86/asm: Add asm macros for static keys/jump labels x86/asm: Error out if asm/jump_label.h is included inappropriately context_tracking: Switch to new static_branch API x86/entry, x86/paravirt: Remove the unused usergs_sysret32 PV op x86/paravirt: Remove the unused irq_enable_sysexit pv op x86/xen: Avoid fast syscall path for Xen PV guests
| * | x86/entry/64_compat: Make labels localBorislav Petkov2015-12-141-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ... so that they don't appear as symbols in the final ELF. Signed-off-by: Borislav Petkov <bp@suse.de> 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: H. Peter Anvin <hpa@zytor.com> 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/1449916077-6506-1-git-send-email-bp@alien8.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | x86/vdso: Enable vdso pvclock access on all vdso variantsAndy Lutomirski2015-12-111-51/+40
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now that pvclock doesn't require access to the fixmap, all vdso variants can use it. The kernel side isn't wired up for 32-bit kernels yet, but this covers 32-bit and x32 userspace on 64-bit kernels. Signed-off-by: Andy Lutomirski <luto@kernel.org> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> 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: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/a7ef693b7a4c88dd2173dc1d4bf6bc27023626eb.1449702533.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | x86/vdso: Remove pvclock fixmap machineryAndy Lutomirski2015-12-112-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Andy Lutomirski <luto@kernel.org> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> 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: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/4933029991103ae44672c82b97a20035f5c1fe4f.1449702533.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | x86/vdso: Get pvclock data from the vvar VMA instead of the fixmapAndy Lutomirski2015-12-114-13/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Andy Lutomirski <luto@kernel.org> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> 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: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/9d37826fdc7e2d2809efe31d5345f97186859284.1449702533.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | x86, vdso, pvclock: Simplify and speed up the vdso pvclock readerAndy Lutomirski2015-12-111-35/+46
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The pvclock vdso code was too abstracted to understand easily and excessively paranoid. Simplify it for a huge speedup. This opens the door for additional simplifications, as the vdso no longer accesses the pvti for any vcpu other than vcpu 0. Before, vclock_gettime using kvm-clock took about 45ns on my machine. With this change, it takes 29ns, which is almost as fast as the pure TSC implementation. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.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: Thomas Gleixner <tglx@linutronix.de> Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/6b51dcc41f1b101f963945c5ec7093d72bdac429.1449702533.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | x86/entry/64: Bypass enter_from_user_mode on non-context-tracking bootsAndy Lutomirski2015-11-242-6/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On CONFIG_CONTEXT_TRACKING kernels that have context tracking disabled at runtime (which includes most distro kernels), we still have the overhead of a call to enter_from_user_mode in interrupt and exception entries. If jump labels are available, this uses the jump label infrastructure to skip the call. Signed-off-by: Andy Lutomirski <luto@kernel.org> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> 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: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/73ee804fff48cd8c66b65b724f9f728a11a8c686.1447361906.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | Merge branch 'x86/urgent' into x86/asm, to pick up dependent fixesIngo Molnar2015-11-241-1/+18
| |\ \ | | | | | | | | | | | | Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | x86/entry, x86/paravirt: Remove the unused usergs_sysret32 PV opBoris Ostrovsky2015-11-231-8/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As result of commit "x86/xen: Avoid fast syscall path for Xen PV guests", usergs_sysret32 pv op is not called by Xen PV guests anymore and since they were the only ones who used it we can safely remove it. Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Reviewed-by: Borislav Petkov <bp@suse.de> Acked-by: Andy Lutomirski <luto@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.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: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: david.vrabel@citrix.com Cc: konrad.wilk@oracle.com Cc: virtualization@lists.linux-foundation.org Cc: xen-devel@lists.xenproject.org Link: http://lkml.kernel.org/r/1447970147-1733-4-git-send-email-boris.ostrovsky@oracle.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | x86/paravirt: Remove the unused irq_enable_sysexit pv opBoris Ostrovsky2015-11-231-6/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As result of commit "x86/xen: Avoid fast syscall path for Xen PV guests", the irq_enable_sysexit pv op is not called by Xen PV guests anymore and since they were the only ones who used it we can safely remove it. Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Reviewed-by: Borislav Petkov <bp@suse.de> Acked-by: Andy Lutomirski <luto@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.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: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: david.vrabel@citrix.com Cc: konrad.wilk@oracle.com Cc: virtualization@lists.linux-foundation.org Cc: xen-devel@lists.xenproject.org Link: http://lkml.kernel.org/r/1447970147-1733-3-git-send-email-boris.ostrovsky@oracle.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | x86/xen: Avoid fast syscall path for Xen PV guestsBoris Ostrovsky2015-11-232-6/+9
| | |/ | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | After 32-bit syscall rewrite, and specifically after commit: 5f310f739b4c ("x86/entry/32: Re-implement SYSENTER using the new C path") ... the stack frame that is passed to xen_sysexit is no longer a "standard" one (i.e. it's not pt_regs). Since we end up calling xen_iret from xen_sysexit we don't need to fix up the stack and instead follow entry_SYSENTER_32's IRET path directly to xen_iret. We can do the same thing for compat mode even though stack does not need to be fixed. This will allow us to drop usergs_sysret32 paravirt op (in the subsequent patch) Suggested-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Reviewed-by: Borislav Petkov <bp@suse.de> Acked-by: Andy Lutomirski <luto@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.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: Thomas Gleixner <tglx@linutronix.de> Cc: david.vrabel@citrix.com Cc: konrad.wilk@oracle.com Cc: virtualization@lists.linux-foundation.org Cc: xen-devel@lists.xenproject.org Link: http://lkml.kernel.org/r/1447970147-1733-2-git-send-email-boris.ostrovsky@oracle.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | x86/entry: Restore traditional SYSENTER calling conventionAndy Lutomirski2015-12-214-19/+51
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It turns out that some Android versions hardcode the SYSENTER calling convention. This is buggy and will cause problems no matter what the kernel does. Nonetheless, we should try to support it. Credit goes to Linus for pointing out a clean way to handle the SYSENTER/SYSCALL clobber differences while preserving straightforward DWARF annotations. I believe that the original offending Android commit was: https://android.googlesource.com/platform%2Fbionic/+/7dc3684d7a2587e43e6d2a8e0e3f39bf759bd535 Reported-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com> Signed-off-by: Andy Lutomirski <luto@kernel.org> Reviewed-and-tested-by: Borislav Petkov <bp@alien8.de> Cc: <mark.gross@intel.com> Cc: Su Tao <tao.su@intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: <frank.wang@intel.com> Cc: <borun.fu@intel.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Mingwei Shi <mingwei.shi@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | | x86/entry: Fix some commentsAndy Lutomirski2015-12-212-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Andy Lutomirski <luto@kernel.org> Reviewed-and-tested-by: Borislav Petkov <bp@alien8.de> Cc: <mark.gross@intel.com> Cc: Su Tao <tao.su@intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: <qiuxu.zhuo@intel.com> Cc: <frank.wang@intel.com> Cc: <borun.fu@intel.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Mingwei Shi <mingwei.shi@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | | x86/xen: Avoid fast syscall path for Xen PV guestsBoris Ostrovsky2015-12-192-6/+9
| |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | After 32-bit syscall rewrite, and specifically after commit: 5f310f739b4c ("x86/entry/32: Re-implement SYSENTER using the new C path") ... the stack frame that is passed to xen_sysexit is no longer a "standard" one (i.e. it's not pt_regs). Since we end up calling xen_iret from xen_sysexit we don't need to fix up the stack and instead follow entry_SYSENTER_32's IRET path directly to xen_iret. We can do the same thing for compat mode even though stack does not need to be fixed. This will allow us to drop usergs_sysret32 paravirt op (in the subsequent patch) Suggested-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Reviewed-by: Borislav Petkov <bp@suse.de> Acked-by: Andy Lutomirski <luto@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.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: Thomas Gleixner <tglx@linutronix.de> Cc: david.vrabel@citrix.com Cc: konrad.wilk@oracle.com Cc: virtualization@lists.linux-foundation.org Cc: xen-devel@lists.xenproject.org Link: http://lkml.kernel.org/r/1447970147-1733-2-git-send-email-boris.ostrovsky@oracle.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | x86/entry/64: Fix irqflag tracing wrt context trackingAndy Lutomirski2015-11-241-1/+18
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Paolo pointed out that enter_from_user_mode could be called while irqflags were traced as though IRQs were on. In principle, this could confuse lockdep. It doesn't cause any problems that I've seen in any configuration, but if I build with CONFIG_DEBUG_LOCKDEP=y, enable a nohz_full CPU, and add code like: if (irqs_disabled()) { spin_lock(&something); spin_unlock(&something); } to the top of enter_from_user_mode, then lockdep will complain without this fix. It seems that lockdep's irqflags sanity checks are too weak to detect this bug without forcing the issue. This patch adds one byte to normal kernels, and it's IMO a bit ugly. I haven't spotted a better way to do this yet, though. The issue is that we can't do TRACE_IRQS_OFF until after SWAPGS (if needed), but we're also supposed to do it before calling C code. An alternative approach would be to call trace_hardirqs_off in enter_from_user_mode. That would be less code and would not bloat normal kernels at all, but it would be harder to see how the code worked. Signed-off-by: Andy Lutomirski <luto@kernel.org> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> 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: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/86237e362390dfa6fec12de4d75a238acb0ae787.1447361906.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* mm: mlock: add new mlock system callEric B Munson2015-11-062-0/+2
| | | | | | | | | | | | | | | | | | | | | | | With the refactored mlock code, introduce a new system call for mlock. The new call will allow the user to specify what lock states are being added. mlock2 is trivial at the moment, but a follow on patch will add a new mlock state making it useful. Signed-off-by: Eric B Munson <emunson@akamai.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Guenter Roeck <linux@roeck-us.net> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Shuah Khan <shuahkh@osg.samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'x86-mm-for-linus' of ↵Linus Torvalds2015-11-041-0/+2
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 mm changes from Ingo Molnar: "The main changes are: continued PAT work by Toshi Kani, plus a new boot time warning about insecure RWX kernel mappings, by Stephen Smalley. The new CONFIG_DEBUG_WX=y warning is marked default-y if CONFIG_DEBUG_RODATA=y is already eanbled, as a special exception, as these bugs are hard to notice and this check already found several live bugs" * 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/mm: Warn on W^X mappings x86/mm: Fix no-change case in try_preserve_large_page() x86/mm: Fix __split_large_page() to handle large PAT bit x86/mm: Fix try_preserve_large_page() to handle large PAT bit x86/mm: Fix gup_huge_p?d() to handle large PAT bit x86/mm: Fix slow_virt_to_phys() to handle large PAT bit x86/mm: Fix page table dump to show PAT bit x86/asm: Add pud_pgprot() and pmd_pgprot() x86/asm: Fix pud/pmd interfaces to handle large PAT bit x86/asm: Add pud/pmd mask interfaces to handle large PAT bit x86/asm: Move PUD_PAGE macros to page_types.h x86/vdso32: Define PGTABLE_LEVELS to 32bit VDSO
| * Merge tag 'v4.3-rc3' into x86/mm, to pick up fixes before applying new changesIngo Molnar2015-10-061-1/+15
| |\ | | | | | | | | | Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | x86/vdso32: Define PGTABLE_LEVELS to 32bit VDSOToshi Kani2015-09-221-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In case of CONFIG_X86_64, vdso32/vclock_gettime.c fakes a 32-bit non-PAE kernel configuration by re-defining it to CONFIG_X86_32. However, it does not re-define CONFIG_PGTABLE_LEVELS leaving it as 4 levels. This mismatch leads <asm/pgtable_type.h> to NOT include <asm-generic/ pgtable-nopud.h> and <asm-generic/pgtable-nopmd.h>, which will cause compile errors when a later patch enhances <asm/pgtable_type.h> to use PUD_SHIFT and PMD_SHIFT. These -nopud & -nopmd headers define these SHIFTs for the 32-bit non-PAE kernel. Fix it by re-defining CONFIG_PGTABLE_LEVELS to 2 levels. Signed-off-by: Toshi Kani <toshi.kani@hpe.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Juergen Gross <jgross@suse.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Konrad Wilk <konrad.wilk@oracle.com> Cc: Robert Elliot <elliott@hpe.com> Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/1442514264-12475-2-git-send-email-toshi.kani@hpe.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | | x86/entry/32: Fix FS and GS restore in opportunistic SYSEXITAndy Lutomirski2015-10-181-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We either need to restore them before popping and thus changing ESP, or we need to adjust the offsets. The former is simpler. Reported-and-tested-by: Borislav Petkov <bp@suse.de> Signed-off-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: 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: Thomas Gleixner <tglx@linutronix.de> Fixes: 5f310f739b4c x86/entry/32: ("Re-implement SYSENTER using the new C path") Link: http://lkml.kernel.org/r/461e5c7d8fa3821529893a4893ac9c4bc37f9e17.1445035014.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | x86/entry/32: Fix entry_INT80_32() to expect interrupts to be onAndy Lutomirski2015-10-183-8/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When I rewrote entry_INT80_32, I thought that int80 was an interrupt gate. It's a trap gate. *facepalm* Thanks to Brian Gerst for pointing out that it's better to change the entry code than to change the gate type. Suggested-by: Brian Gerst <brgerst@gmail.com> Reported-and-tested-by: Borislav Petkov <bp@suse.de> Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> 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: Thomas Gleixner <tglx@linutronix.de> Fixes: 150ac78d63af ("x86/entry/32: Switch INT80 to the new C syscall path") Link: http://lkml.kernel.org/r/dc09d9b574a5c1dcca996847875c73f8341ce0ad.1445035014.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | x86/entry/64/compat: Document sysenter_fix_flags's reason for existenceBorislav Petkov2015-10-111-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The code under the label can normally be inline, without the jumping back and forth but the latter is an optimization. Document that. Signed-off-by: Borislav Petkov <bp@suse.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: 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: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20151009170859.GA24266@pd.tnic Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | x86/entry: Split and inline syscall_return_slowpath()Andy Lutomirski2015-10-091-21/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | GCC is unable to properly optimize functions that have a very short likely case and a longer and register-heavier cold part -- it fails to sink all of the register saving and stack frame setup code into the unlikely part. Help it out with syscall_return_slowpath() by splitting it into two parts and inline the hot part. Saves 6 cycles for compat syscalls. Signed-off-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: 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: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/0f773a894ab15c589ac794c2d34ca6ba9b5335c9.1444091585.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | x86/entry: Split and inline prepare_exit_to_usermode()Andy Lutomirski2015-10-091-15/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | GCC is unable to properly optimize functions that have a very short likely case and a longer and register-heavier cold part -- it fails to sink all of the register saving and stack frame setup code into the unlikely part. Help it out with prepare_exit_to_usermode() by splitting it into two parts and inline the hot part. Saves 6-8 cycles for compat syscalls. Signed-off-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: 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: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/9fc53eda4a5b924070952f12fa4ae3e477640a07.1444091585.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | x86/entry: Use pt_regs_to_thread_info() in syscall entry tracingAndy Lutomirski2015-10-091-11/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It generates simpler and faster code than current_thread_info(). Signed-off-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: 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: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/a3b6633e7dcb9f673c1b619afae602d29d27d2cf.1444091585.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
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