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: c5c46f59 ("x86/entry: Add new, comprehensible entry and exit handlers written in C")
Link: http://lkml.kernel.org/r/cbce3cf545522f64eb37f5478cb59746230db3b5.1455142412.git.luto@kernel.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

This catches a regression from the compat syscall rework.  The
32-bit variant of this test currently fails.  The issue is that, for
a 32-bit tracer and a 32-bit tracee, GETREGS+SETREGS with no changes
should be a no-op.  It currently isn't a no-op if RAX indicates
signal restart, because the high bits get cleared and the kernel
loses track of the restart state.
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>
Link: http://lkml.kernel.org/r/c4040b40b5b4a37ed31375a69b683f753ec6788a.1455142412.git.luto@kernel.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

I had some obvious typos.
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: Robert O'Callahan <robert@ocallahan.org>
Cc: Shuah Khan <shuahkh@osg.samsung.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/e5e6772d4802986cf7df702e646fa24ac14f2204.1455142412.git.luto@kernel.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

In order to keep this file's size sensible and not cause too much
unnecessary churn, make the rule explicit - similar to pci_ids.h - that
only MSRs which are used in multiple compilation units, should get added
to it.
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: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: alex.williamson@redhat.com
Cc: gleb@kernel.org
Cc: joro@8bytes.org
Cc: kvm@vger.kernel.org
Cc: sherry.hurwitz@amd.com
Cc: wei@redhat.com
Link: http://lkml.kernel.org/r/1455612202-14414-5-git-send-email-bp@alien8.deSigned-off-by: Ingo Molnar <mingo@kernel.org>

One of ftrace_caller_end and ftrace_return is redundant so unify them.
Rename ftrace_return to ftrace_epilogue to mean that everything after
that label represents, like an afterword, work which happens *after* the
ftrace call, e.g., the function graph tracer for one.

Steve wants this to rather mean "[a]n event which reflects meaningfully
on a recently ended conflict or struggle." I can imagine that ftrace can
be a struggle sometimes.

Anyway, beef up the comment about the code contents and layout before
ftrace_epilogue label.
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Steven Rostedt <rostedt@goodmis.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/1455612202-14414-4-git-send-email-bp@alien8.deSigned-off-by: Ingo Molnar <mingo@kernel.org>

This tests the two ABI-preserving cases that DOSEMU cares about, and
it also explicitly tests the new UC_SIGCONTEXT_SS and
UC_STRICT_RESTORE_SS flags.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Shuah Khan <shuahkh@osg.samsung.com>
Cc: Stas Sergeev <stsp@list.ru>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/f3d08f98541d0bd3030ceb35e05e21f59e30232c.1455664054.git.luto@kernel.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

This is a second attempt to make the improvements from c6f20629
("x86/signal/64: Fix SS handling for signals delivered to 64-bit
programs"), which was reverted by 51adbfbba5c6 ("x86/signal/64: Add
support for SS in the 64-bit signal context").

This adds two new uc_flags flags.  UC_SIGCONTEXT_SS will be set for
all 64-bit signals (including x32).  It indicates that the saved SS
field is valid and that the kernel supports the new behavior.

The goal is to fix a problems with signal handling in 64-bit tasks:
SS wasn't saved in the 64-bit signal context, making it awkward to
determine what SS was at the time of signal delivery and making it
impossible to return to a non-flat SS (as calling sigreturn clobbers
SS).

This also made it extremely difficult for 64-bit tasks to return to
fully-defined 16-bit contexts, because only the kernel can easily do
espfix64, but sigreturn was unable to set a non-flag SS:ESP.
(DOSEMU has a monstrous hack to partially work around this
limitation.)

If we could go back in time, the correct fix would be to make 64-bit
signals work just like 32-bit signals with respect to SS: save it
in signal context, reset it when delivering a signal, and restore
it in sigreturn.

Unfortunately, doing that (as I tried originally) breaks DOSEMU:
DOSEMU wouldn't reset the signal context's SS when clearing the LDT
and changing the saved CS to 64-bit mode, since it predates the SS
context field existing in the first place.

This patch is a bit more complicated, and it tries to balance a
bunch of goals.  It makes most cases of changing ucontext->ss during
signal handling work as expected.

I do this by special-casing the interesting case.  On sigreturn,
ucontext->ss will be honored by default, unless the ucontext was
created from scratch by an old program and had a 64-bit CS
(unfortunately, CRIU can do this) or was the result of changing a
32-bit signal context to 64-bit without resetting SS (as DOSEMU
does).

For the benefit of new 64-bit software that uses segmentation (new
versions of DOSEMU might), the new behavior can be detected with a
new ucontext flag UC_SIGCONTEXT_SS.

To avoid compilation issues, __pad0 is left as an alias for ss in
ucontext.

The nitty-gritty details are documented in the header file.

This patch also re-enables the sigreturn_64 and ldt_gdt_64 selftests,
as the kernel change allows both of them to pass.
Tested-by: Stas Sergeev <stsp@list.ru>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/749149cbfc3e75cd7fcdad69a854b399d792cc6f.1455664054.git.luto@kernel.org
[ Small readability edit. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Signals are always delivered to 64-bit tasks with CS set to a long
mode segment.  In long mode, SS doesn't matter as long as it's a
present writable segment.

If SS starts out invalid (this can happen if the signal was caused
by an IRET fault or was delivered on the way out of set_thread_area
or modify_ldt), then IRET to the signal handler can fail, eventually
killing the task.

The straightforward fix would be to simply reset SS when delivering
a signal.  That breaks DOSEMU, though: 64-bit builds of DOSEMU rely
on SS being set to the faulting SS when signals are delivered.

As a compromise, this patch leaves SS alone so long as it's valid.

The net effect should be that the behavior of successfully delivered
signals is unchanged.  Some signals that would previously have
failed to be delivered will now be delivered successfully.

This has no effect for x32 or 32-bit tasks: their signal handlers
were already called with SS == __USER_DS.

(On Xen, there's a slight hole: if a task sets SS to a writable
 *kernel* data segment, then we will fail to identify it as invalid
 and we'll still kill the task.  If anyone cares, this could be fixed
 with a new paravirt hook.)
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stas Sergeev <stsp@list.ru>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/163c6e1eacde41388f3ff4d2fe6769be651d7b6e.1455664054.git.luto@kernel.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

These fields have a strange history.  This tries to document it.

This borrows from 9a036b93 ("x86/signal/64: Remove 'fs' and 'gs'
from sigcontext"), which was reverted by ed596cde ("Revert x86
sigcontext cleanups").
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stas Sergeev <stsp@list.ru>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/baa78f3c84106fa5acbc319377b1850602f5deec.1455664054.git.luto@kernel.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

When GCC cannot do constant folding for this macro, it falls back to
cpu_has(). But static_cpu_has() is optimal and it works at all times
now. So use it and speedup the fallback case.

Before we had this:

  mov    0x99d674(%rip),%rdx        # ffffffff81b0d9f4 <boot_cpu_data+0x34>
  shr    $0x2e,%rdx
  and    $0x1,%edx
  jne    ffffffff811704e9 <do_munmap+0x3f9>

After alternatives patching, it turns into:

		  jmp    0xffffffff81170390
		  nopl   (%rax)
		  ...
		  callq  ffffffff81056e00 <mpx_notify_unmap>
ffffffff81170390: mov    0x170(%r12),%rdi
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Joerg Roedel <joro@8bytes.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/1455578358-28347-1-git-send-email-bp@alien8.deSigned-off-by: Ingo Molnar <mingo@kernel.org>

track_pfn_insert() overwrites the pgprot that is passed in with a value
based on the VMA's page_prot.  This is a problem for people trying to
do clever things with the new vm_insert_pfn_prot() as it will simply
overwrite the passed protection flags.  If we use the current value of
the pgprot as the base, then it will behave as people are expecting.

Also fix track_pfn_remap() in the same way.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Kees Cook <keescook@chromium.org>
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/1453742717-10326-2-git-send-email-matthew.r.wilcox@intel.comSigned-off-by: Ingo Molnar <mingo@kernel.org>

Sometimes GCC mysteriously doesn't inline very small functions
we expect to be inlined, see:

  https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66122

Arguably, GCC should do better, but GCC people aren't willing
to invest time into it and are asking to use __always_inline
instead.

With this .config:

  http://busybox.net/~vda/kernel_config_OPTIMIZE_INLINING_and_Os

here's an example of functions getting deinlined many times:

  test_and_set_bit (166 copies, ~1260 calls)
         55                      push   %rbp
         48 89 e5                mov    %rsp,%rbp
         f0 48 0f ab 3e          lock bts %rdi,(%rsi)
         72 04                   jb     <test_and_set_bit+0xf>
         31 c0                   xor    %eax,%eax
         eb 05                   jmp    <test_and_set_bit+0x14>
         b8 01 00 00 00          mov    $0x1,%eax
         5d                      pop    %rbp
         c3                      retq

  test_and_clear_bit (124 copies, ~1000 calls)
         55                      push   %rbp
         48 89 e5                mov    %rsp,%rbp
         f0 48 0f b3 3e          lock btr %rdi,(%rsi)
         72 04                   jb     <test_and_clear_bit+0xf>
         31 c0                   xor    %eax,%eax
         eb 05                   jmp    <test_and_clear_bit+0x14>
         b8 01 00 00 00          mov    $0x1,%eax
         5d                      pop    %rbp
         c3                      retq

  change_bit (3 copies, 8 calls)
         55                      push   %rbp
         48 89 e5                mov    %rsp,%rbp
         f0 48 0f bb 3e          lock btc %rdi,(%rsi)
         5d                      pop    %rbp
         c3                      retq

  clear_bit_unlock (2 copies, 11 calls)
         55                      push   %rbp
         48 89 e5                mov    %rsp,%rbp
         f0 48 0f b3 3e          lock btr %rdi,(%rsi)
         5d                      pop    %rbp
         c3                      retq

This patch works it around via s/inline/__always_inline/.

Code size decrease by ~13.5k after the patch:

      text     data      bss       dec    filename
  92110727 20826144 36417536 149354407    vmlinux.before
  92097234 20826176 36417536 149340946    vmlinux.after
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
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: David Rientjes <rientjes@google.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: Thomas Graf <tgraf@suug.ch>
Link: http://lkml.kernel.org/r/1454881887-1367-1-git-send-email-dvlasenk@redhat.comSigned-off-by: Ingo Molnar <mingo@kernel.org>

Make the preemption and interrupt flag handling more readable by
removing preempt_conditional_sti() and preempt_conditional_cli()
helpers and using preempt_disable() and
preempt_enable_no_resched() instead.

Rename contitional_sti() and conditional_cli() to the more
understandable cond_local_irq_enable() and
cond_local_irq_disable() respectively, while at it.
Suggested-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com>
[ Boris: massage text. ]
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: 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: Tony Luck <tony.luck@intel.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1453750913-4781-2-git-send-email-bp@alien8.deSigned-off-by: Ingo Molnar <mingo@kernel.org>

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.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

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: 1e423bff x86/entry/64: ("Migrate the 64-bit syscall slow path to C")
Link: http://lkml.kernel.org/r/a85f8360c397e48186a9bc3e565ad74307a7b011.1454261517.git.luto@kernel.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

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: 1e423bff x86/entry/64: ("Migrate the 64-bit syscall slow path to C")
Link: http://lkml.kernel.org/r/ab92cd365fb7b0a56869e920017790d96610fdca.1454261517.git.luto@kernel.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

... 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.deSigned-off-by: Ingo Molnar <mingo@kernel.org>

Move the code to do the dynamic check to the altinstr_aux
section so that it is discarded after alternatives have run and
a static branch has been chosen.

This way we're changing the dynamic branch from C code to
assembly, which makes it *substantially* smaller while avoiding
a completely unnecessary call to an out of line function.
Signed-off-by: Brian Gerst <brgerst@gmail.com>
[ Changed it to do TESTB, as hpa suggested. ]
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Young <dyoung@redhat.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kristen Carlson Accardi <kristen@linux.intel.com>
Cc: Laura Abbott <labbott@fedoraproject.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1452972124-7380-1-git-send-email-brgerst@gmail.com
Link: http://lkml.kernel.org/r/20160127084525.GC30712@pd.tnicSigned-off-by: Ingo Molnar <mingo@kernel.org>

Add .altinstr_aux for additional instructions which will be used
before and/or during patching. All stuff which needs more
sophisticated patching should go there. See next patch.
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/1453842730-28463-8-git-send-email-bp@alien8.deSigned-off-by: Ingo Molnar <mingo@kernel.org>

I can simply quote hpa from the mail:

  "Get rid of the non-asm goto variant and just fall back to
   dynamic if asm goto is unavailable. It doesn't make any sense,
   really, if it is supposed to be safe, and by now the asm
   goto-capable gcc is in more wide use. (Originally the gcc 3.x
   fallback to pure dynamic didn't exist, either.)"

Booy, am I lazy.

Cleanup the whole CC_HAVE_ASM_GOTO ifdeffery too, while at it.
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/20160127084325.GB30712@pd.tnicSigned-off-by: Ingo Molnar <mingo@kernel.org>

So the old one didn't work properly before alternatives had run.
And it was supposed to provide an optimized JMP because the
assumption was that the offset it is jumping to is within a
signed byte and thus a two-byte JMP.

So I did an x86_64 allyesconfig build and dumped all possible
sites where static_cpu_has() was used. The optimization amounted
to all in all 12(!) places where static_cpu_has() had generated
a 2-byte JMP. Which has saved us a whopping 36 bytes!

This clearly is not worth the trouble so we can remove it. The
only place where the optimization might count - in __switch_to()
- we will handle differently. But that's not subject of this
patch.
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/1453842730-28463-6-git-send-email-bp@alien8.deSigned-off-by: Ingo Molnar <mingo@kernel.org>

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.deSigned-off-by: Ingo Molnar <mingo@kernel.org>

Signed-off-by: Ingo Molnar <mingo@kernel.org>

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.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

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.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

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.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

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.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

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.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

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.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

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.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

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.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

This checks that ELF binaries are started with an appropriately
blank register state.

( There's currently a nasty special case in the entry asm to
  arrange for this. I'm planning on removing the special case,
  and this will help make sure I don't break it. )
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/ef54f8d066b30a3eb36bbf26300eebb242185700.1454022279.git.luto@kernel.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

Previously the Makefile supported 32-bit-only tests and tests
that were 32-bit and 64-bit.  This adds the support for tests
that are only built as 64-bit binaries.

There aren't any yet, but there might be a few some day.
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: Shuah Khan <shuahkhan@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-api@vger.kernel.org
Link: http://lkml.kernel.org/r/99789bfe65706e6df32cc7e13f656e8c9fa92031.1454022279.git.luto@kernel.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

Signed-off-by: Ingo Molnar <mingo@kernel.org>

L3_PAGE_OFFSET was introduced in commit a6523748 (paravirt/x86, 64-bit: move
__PAGE_OFFSET to leave a space for hypervisor), but has no users.
Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Link: http://lkml.kernel.org/r/1453810881-30622-1-git-send-email-kuleshovmail@gmail.comSigned-off-by: Thomas Gleixner <tglx@linutronix.de>

Pull MIPS updates from Ralf Baechle:
 "This is the main pull request for MIPS for 4.5 plus some 4.4 fixes.

  The executive summary:

   - ATH79 platform improvments, use DT bindings for the ATH79 USB PHY.
   - Avoid useless rebuilds for zboot.
   - jz4780: Add NEMC, BCH and NAND device tree nodes
   - Initial support for the MicroChip's DT platform.  As all the device
     drivers are missing this is still of limited use.
   - Some Loongson3 cleanups.
   - The unavoidable whitespace polishing.
   - Reduce clock skew when synchronizing the CPU cycle counters on CPU
     startup.
   - Add MIPS R6 fixes.
   - Lots of cleanups across arch/mips as fallout from KVM.
   - Lots of minor fixes and changes for IEEE 754-2008 support to the
     FPU emulator / fp-assist software.
   - Minor Ralink, BCM47xx and bcm963xx platform support improvments.
   - Support SMP on BCM63168"

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus: (84 commits)
  MIPS: zboot: Add support for serial debug using the PROM
  MIPS: zboot: Avoid useless rebuilds
  MIPS: BMIPS: Enable ARCH_WANT_OPTIONAL_GPIOLIB
  MIPS: bcm63xx: nvram: Remove unused bcm63xx_nvram_get_psi_size() function
  MIPS: bcm963xx: Update bcm_tag field image_sequence
  MIPS: bcm963xx: Move extended flash address to bcm_tag header file
  MIPS: bcm963xx: Move Broadcom BCM963xx image tag data structure
  MIPS: bcm63xx: nvram: Use nvram structure definition from header file
  MIPS: bcm963xx: Add Broadcom BCM963xx board nvram data structure
  MAINTAINERS: Add KVM for MIPS entry
  MIPS: KVM: Add missing newline to kvm_err()
  MIPS: Move KVM specific opcodes into asm/inst.h
  MIPS: KVM: Use cacheops.h definitions
  MIPS: Break down cacheops.h definitions
  MIPS: Use EXCCODE_ constants with set_except_vector()
  MIPS: Update trap codes
  MIPS: Move Cause.ExcCode trap codes to mipsregs.h
  MIPS: KVM: Make kvm_mips_{init,exit}() static
  MIPS: KVM: Refactor added offsetof()s
  MIPS: KVM: Convert EXPORT_SYMBOL to _GPL
  ...

Merge tag 'platform-drivers-x86-v4.5-2' of git://git.infradead.org/users/dvhart/linux-platform-drivers-x86

Pull x86 platform driver updates from Darren Hart:
 "Emergency travel prevented me from completing my final testing on this
  until today.  Nothing here that couldn't wait until RC1 fixes, but I
  thought it best to get it out sooner rather than later as it does
  contain a build warning fix.

  Summary:

  A build warning fix, MAINTAINERS cleanup, and a new DMI quirk:

  ideapad-laptop:
   - Add Lenovo Yoga 700 to no_hw_rfkill dmi list

  MAINTAINERS:
   - Combine multiple telemetry entries

  intel_telemetry_debugfs:
   - Fix unused warnings in telemetry debugfs"

* tag 'platform-drivers-x86-v4.5-2' of git://git.infradead.org/users/dvhart/linux-platform-drivers-x86:
  ideapad-laptop: Add Lenovo Yoga 700 to no_hw_rfkill dmi list
  MAINTAINERS: Combine multiple telemetry entries
  intel_telemetry_debugfs: Fix unused warnings in telemetry debugfs

Pull thermal management updates from Zhang Rui:
 "The top merge commit was re-generated yesterday because two topic
  branches were dropped from this pull request in the last minute due to
  some unaddressed comments.  All the other material has been in
  linux-next for quite a while.

  Specifics:

   - Enhance thermal core to handle unexpected device cooling states
     after fresh boot and system resume.  From Zhang Rui and Chen Yu.

   - Several fixes and cleanups on Rockchip and RCAR thermal drivers.
     From Caesar Wang and Kuninori Morimoto.

   - Add Broxton support for Intel processor thermal reporting device
     driver.  From Amy Wiles"

* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux:
  thermal: trip_point_temp_store() calls thermal_zone_device_update()
  thermal: rcar: rcar_thermal_get_temp() return error if strange temp
  thermal: rcar: check irq possibility in rcar_thermal_irq_xxx()
  thermal: rcar: check every rcar_thermal_update_temp() return value
  thermal: rcar: move rcar_thermal_dt_ids to upside
  thermal: rockchip: Support the RK3399 SoCs in thermal driver
  thermal: rockchip: Support the RK3228 SoCs in thermal driver
  dt-bindings: rockchip-thermal: Support the RK3228/RK3399 SoCs compatible
  thermal: rockchip: fix a trivial typo
  Thermal: Enable Broxton SoC thermal reporting device
  thermal: constify pch_dev_ops structure
  Thermal: do thermal zone update after a cooling device registered
  Thermal: handle thermal zone device properly during system sleep
  Thermal: initialize thermal zone device correctly

Pull 9p updates from Eric Van Hensbergen:
 "Sorry for the last minute pull request, there's was a change that
  didn't get pulled into for-next until two weeks ago and I wanted to
  give it some bake time.

  Summary:

  Rework and error handling fixes, primarily in the fscatch and fd
  transports"

* tag 'for-linus-4.5-merge-window' of git://git.kernel.org/pub/scm/linux/kernel/git/ericvh/v9fs:
  fs/9p: use fscache mutex rather than spinlock
  9p: trans_fd, bail out if recv fcall if missing
  9p: trans_fd, read rework to use p9_parse_header
  net/9p: Add device name details on error