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Right after SYSENTER, we can get a #DB or NMI. On x86_32, there's no IST,
so the exception handler is invoked on the temporary SYSENTER stack.
Because the SYSENTER stack is very small, we have a fixup to switch
off the stack quickly when this happens. The old fixup had several issues:
1. It checked the interrupt frame's CS and EIP. This wasn't
obviously correct on Xen or if vm86 mode was in use [1].
2. In the NMI handler, it did some frightening digging into the
stack frame. I'm not convinced this digging was correct.
3. The fixup didn't switch stacks and then switch back. Instead, it
synthesized a brand new stack frame that would redirect the IRET
back to the SYSENTER code. That frame was highly questionable.
For one thing, if NMI nested inside #DB, we would effectively
abort the #DB prologue, which was probably safe but was
frightening. For another, the code used PUSHFL to write the
FLAGS portion of the frame, which was simply bogus -- by the time
PUSHFL was called, at least TF, NT, VM, and all of the arithmetic
flags were clobbered.
Simplify this considerably. Instead of looking at the saved frame
to see where we came from, check the hardware ESP register against
the SYSENTER stack directly. Malicious user code cannot spoof the
kernel ESP register, and by moving the check after SAVE_ALL, we can
use normal PER_CPU accesses to find all the relevant addresses.
With this patch applied, the improved syscall_nt_32 test finally
passes on 32-bit kernels.
[1] It isn't obviously correct, but it is nonetheless safe from vm86
shenanigans as far as I can tell. A user can't point EIP at
entry_SYSENTER_32 while in vm86 mode because entry_SYSENTER_32,
like all kernel addresses, is greater than 0xffff and would thus
violate the CS segment limit.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andrew Cooper <andrew.cooper3@citrix.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: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/b2cdbc037031c07ecf2c40a96069318aec0e7971.1457578375.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Due to a blatant design error, SYSENTER doesn't clear TF (single-step).
As a result, if a user does SYSENTER with TF set, we will single-step
through the kernel until something clears TF. There is absolutely
nothing we can do to prevent this short of turning off SYSENTER [1].
Simplify the handling considerably with two changes:
1. We already sanitize EFLAGS in SYSENTER to clear NT and AC. We can
add TF to that list of flags to sanitize with no overhead whatsoever.
2. Teach do_debug() to ignore single-step traps in the SYSENTER prologue.
That's all we need to do.
Don't get too excited -- our handling is still buggy on 32-bit
kernels. There's nothing wrong with the SYSENTER code itself, but
the #DB prologue has a clever fixup for traps on the very first
instruction of entry_SYSENTER_32, and the fixup doesn't work quite
correctly. The next two patches will fix that.
[1] We could probably prevent it by forcing BTF on at all times and
making sure we clear TF before any branches in the SYSENTER
code. Needless to say, this is a bad idea.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andrew Cooper <andrew.cooper3@citrix.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: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/a30d2ea06fe4b621fe6a9ef911b02c0f38feb6f2.1457578375.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Leaving any bits set in DR6 on return from a debug exception is
asking for trouble. Prevent it by writing zero right away and
clarify the comment.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andrew Cooper <andrew.cooper3@citrix.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: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/3857676e1be8fb27db4b89bbb1e2052b7f435ff4.1457578375.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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The SDM says that debug exceptions clear BTF, and we need to keep
TIF_BLOCKSTEP in sync with BTF. Clear it unconditionally and improve
the comment.
I suspect that the fact that kmemcheck could cause TIF_BLOCKSTEP not
to be cleared was just an oversight.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andrew Cooper <andrew.cooper3@citrix.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: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/fa86e55d196e6dde5b38839595bde2a292c52fdc.1457578375.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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After fixing FPU option parsing, we now parse the 'no387' boot option
too early: no387 clears X86_FEATURE_FPU before it's even probed, so
the boot CPU promptly re-enables it.
I suspect it gets even more confused on SMP.
Fix the probing code to leave X86_FEATURE_FPU off if it's been
disabled by setup_clear_cpu_cap().
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: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.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: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: yu-cheng yu <yu-cheng.yu@intel.com>
Fixes: 4f81cbafcce2 ("x86/fpu: Fix early FPU command-line parsing")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Several cases of overlapping changes, as well as one instance
(vxlan) of a bug fix in 'net' overlapping with code movement
in 'net-next'.
Signed-off-by: David S. Miller <davem@davemloft.net>
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Make use of the EXTABLE_FAULT exception table entries to write
a kernel copy routine that doesn't crash the system if it
encounters a machine check. Prime use case for this is to copy
from large arrays of non-volatile memory used as storage.
We have to use an unrolled copy loop for now because current
hardware implementations treat a machine check in "rep mov"
as fatal. When that is fixed we can simplify.
Return type is a "bool". True means that we copied OK, false means
that it didn't.
Signed-off-by: Tony Luck <tony.luck@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@gmail.com>
Link: http://lkml.kernel.org/r/a44e1055efc2d2a9473307b22c91caa437aa3f8b.1456439214.git.tony.luck@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Signed-off-by: Ingo Molnar <mingo@kernel.org>
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It no longer has any users.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: Andrew Cooper <andrew.cooper3@citrix.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: Luis R. Rodriguez <mcgrof@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: boris.ostrovsky@oracle.com
Cc: david.vrabel@citrix.com
Cc: konrad.wilk@oracle.com
Cc: lguest@lists.ozlabs.org
Cc: xen-devel@lists.xensource.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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x86_64 has very clean espfix handling on paravirt: espfix64 is set
up in native_iret, so paravirt systems that override iret bypass
espfix64 automatically. This is robust and straightforward.
x86_32 is messier. espfix is set up before the IRET paravirt patch
point, so it can't be directly conditionalized on whether we use
native_iret. We also can't easily move it into native_iret without
regressing performance due to a bizarre consideration. Specifically,
on 64-bit kernels, the logic is:
if (regs->ss & 0x4)
setup_espfix;
On 32-bit kernels, the logic is:
if ((regs->ss & 0x4) && (regs->cs & 0x3) == 3 &&
(regs->flags & X86_EFLAGS_VM) == 0)
setup_espfix;
The performance of setup_espfix itself is essentially irrelevant, but
the comparison happens on every IRET so its performance matters. On
x86_64, there's no need for any registers except flags to implement
the comparison, so we fold the whole thing into native_iret. On
x86_32, we don't do that because we need a free register to
implement the comparison efficiently. We therefore do espfix setup
before restoring registers on x86_32.
This patch gets rid of the explicit paravirt_enabled check by
introducing X86_BUG_ESPFIX on 32-bit systems and using an ALTERNATIVE
to skip espfix on paravirt systems where iret != native_iret. This is
also messy, but it's at least in line with other things we do.
This improves espfix performance by removing a branch, but no one
cares. More importantly, it removes a paravirt_enabled user, which is
good because paravirt_enabled is ill-defined and is going away.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: Andrew Cooper <andrew.cooper3@citrix.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: Luis R. Rodriguez <mcgrof@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: boris.ostrovsky@oracle.com
Cc: david.vrabel@citrix.com
Cc: konrad.wilk@oracle.com
Cc: lguest@lists.ozlabs.org
Cc: xen-devel@lists.xensource.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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ignore_nmis is used in two distinct places:
1. modified through {stop,restart}_nmi by alternative_instructions
2. read by do_nmi to determine if default_do_nmi should be called or not
thus the access pattern conforms to __read_mostly and do_nmi() is a fastpath.
Signed-off-by: Kostenzer Felix <fkostenzer@live.at>
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
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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_flat_send_IPI_mask: 157 bytes, 3 callsites
text data bss dec hex filename
96183823 20860520 36122624 153166967 9212477 vmlinux1_before
96183699 20860520 36122624 153166843 92123fb vmlinux
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Borislav Petkov <bp@alien.de>
Cc: Daniel J Blueman <daniel@numascale.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Travis <travis@sgi.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/1457287876-6001-2-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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__default_send_IPI_shortcut: 49 bytes, 2 callsites
__default_send_IPI_dest_field: 108 bytes, 7 callsites
text data bss dec hex filename
96184086 20860488 36122624 153167198 921255e vmlinux_before
96183823 20860520 36122624 153166967 9212477 vmlinux
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Borislav Petkov <bp@alien.de>
Cc: Daniel J Blueman <daniel@numascale.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Travis <travis@sgi.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/1457287876-6001-1-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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In an attempt to aid in understanding of what the threshold_block
structure holds, provide comments to describe the members here. Also,
trim comments around threshold_restart_bank() and update copyright info.
No functional change is introduced.
Signed-off-by: Aravind Gopalakrishnan <Aravind.Gopalakrishnan@amd.com>
[ Shorten comments. ]
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/1457021458-2522-6-git-send-email-Aravind.Gopalakrishnan@amd.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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In upcoming processors, the BLKPTR field is no longer used to indicate
the MSR number of the additional register. Insted, it simply indicates
the prescence of additional MSRs.
Fix the logic here to gather MSR address from MSR_AMD64_SMCA_MCx_MISC()
for newer processors and fall back to existing logic for older
processors.
[ Drop nextaddr_out label; style cleanups. ]
Signed-off-by: Aravind Gopalakrishnan <Aravind.Gopalakrishnan@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/1457021458-2522-4-git-send-email-Aravind.Gopalakrishnan@amd.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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For Scalable MCA enabled processors, errors are listed per IP block. And
since it is not required for an IP to map to a particular bank, we need
to use HWID and McaType values from the MCx_IPID register to figure out
which IP a given bank represents.
We also have a new bit (TCC) in the MCx_STATUS register to indicate Task
context is corrupt.
Add logic here to decode errors from all known IP blocks for Fam17h
Model 00-0fh and to print TCC errors.
[ Minor fixups. ]
Signed-off-by: Aravind Gopalakrishnan <Aravind.Gopalakrishnan@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/1457021458-2522-3-git-send-email-Aravind.Gopalakrishnan@amd.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Signed-off-by: Ingo Molnar <mingo@kernel.org>
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It is 0 because for !0 values we would have exited already.
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/1457345404-28884-6-git-send-email-bp@alien8.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Turn them into proper sentences. Add comments to microcode_sanity_check() to
explain what it does.
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/1457345404-28884-5-git-send-email-bp@alien8.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Merge the two consecutive "if (ext_table_size)". No functional change.
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/1457345404-28884-4-git-send-email-bp@alien8.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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sizeof(u32) is perfectly clear as it is.
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/1457345404-28884-3-git-send-email-bp@alien8.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Microcode checksum verification should be done using unsigned 32-bit
values otherwise the calculation overflow results in undefined
behaviour.
This is also nicely documented in the SDM, section "Microcode Update
Checksum":
"To check for a corrupt microcode update, software must perform a
unsigned DWORD (32-bit) checksum of the microcode update. Even though
some fields are signed, the checksum procedure treats all DWORDs as
unsigned. Microcode updates with a header version equal to 00000001H
must sum all DWORDs that comprise the microcode update. A valid
checksum check will yield a value of 00000000H."
but for some reason the code has been using ints from the very
beginning.
In practice, this bug possibly manifested itself only when doing the
microcode data checksum - apparently, currently shipped Intel microcode
doesn't have an extended signature table for which we do checksum
verification too.
UBSAN: Undefined behaviour in arch/x86/kernel/cpu/microcode/intel_lib.c:105:12
signed integer overflow:
-1500151068 + -2125470173 cannot be represented in type 'int'
CPU: 0 PID: 0 Comm: swapper Not tainted 4.5.0-rc5+ #495
...
Call Trace:
dump_stack
? inotify_ioctl
ubsan_epilogue
handle_overflow
__ubsan_handle_add_overflow
microcode_sanity_check
get_matching_model_microcode.isra.2.constprop.8
? early_idt_handler_common
? strlcpy
? find_cpio_data
load_ucode_intel_bsp
load_ucode_bsp
? load_ucode_bsp
x86_64_start_kernel
[ Expand and massage commit message. ]
Signed-off-by: Chris Bainbridge <chris.bainbridge@gmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: hmh@hmh.eng.br
Link: http://lkml.kernel.org/r/1456834359-5132-1-git-send-email-chris.bainbridge@gmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Signed-off-by: Ingo Molnar <mingo@kernel.org>
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On modern Intel systems TSC is derived from the new Always Running Timer
(ART). ART can be captured simultaneous to the capture of
audio and network device clocks, allowing a correlation between timebases
to be constructed. Upon capture, the driver converts the captured ART
value to the appropriate system clock using the correlated clocksource
mechanism.
On systems that support ART a new CPUID leaf (0x15) returns parameters
“m” and “n” such that:
TSC_value = (ART_value * m) / n + k [n >= 1]
[k is an offset that can adjusted by a privileged agent. The
IA32_TSC_ADJUST MSR is an example of an interface to adjust k.
See 17.14.4 of the Intel SDM for more details]
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: kevin.b.stanton@intel.com
Cc: kevin.j.clarke@intel.com
Cc: hpa@zytor.com
Cc: jeffrey.t.kirsher@intel.com
Cc: netdev@vger.kernel.org
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Christopher S. Hall <christopher.s.hall@intel.com>
[jstultz: Tweaked to fix build issue, also reworked math for
64bit division on 32bit systems, as well as !CONFIG_CPU_FREQ build
fixes]
Signed-off-by: John Stultz <john.stultz@linaro.org>
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Pause/unpause graph tracing around do_suspend_lowlevel as it has
inconsistent call/return info after it jumps to the wakeup vector.
The graph trace buffer will otherwise become misaligned and
may eventually crash and hang on suspend.
To reproduce the issue and test the fix:
Run a function_graph trace over suspend/resume and set the graph
function to suspend_devices_and_enter. This consistently hangs the
system without this fix.
Signed-off-by: Todd Brandt <todd.e.brandt@linux.intel.com>
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Let the non boot cpus call into idle with the corresponding hotplug state, so
the hotplug core can handle the further bringup. That's a first step to
convert the boot side of the hotplugged cpus to do all the synchronization
with the other side through the state machine. For now it'll only start the
hotplug thread and kick the full bringup of the cpu.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: Rik van Riel <riel@redhat.com>
Cc: Rafael Wysocki <rafael.j.wysocki@intel.com>
Cc: "Srivatsa S. Bhat" <srivatsa@mit.edu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Turner <pjt@google.com>
Link: http://lkml.kernel.org/r/20160226182341.614102639@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Signed-off-by: Ingo Molnar <mingo@kernel.org>
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For per package oriented services we must be able to rely on the number of CPU
packages to be within bounds. Create a tracking facility, which
- calculates the number of possible packages depending on nr_cpu_ids after boot
- makes sure that the package id is within the number of possible packages. If
the apic id is outside we map it to a logical package id if there is enough
space available.
Provide interfaces for drivers to query the mapping and do translations from
physcial to logical ids.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andi Kleen <andi.kleen@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Arnaldo Carvalho de Melo <acme@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: Harish Chegondi <harish.chegondi@intel.com>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/20160222221011.541071755@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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objtool reports the following warning for kretprobe_trampoline():
arch/x86/kernel/kprobes/core.o: warning: objtool: kretprobe_trampoline()+0x20: call without frame pointer save/setup
kretprobes are a special case where the stack is intentionally wrong.
The return address isn't known at the beginning of the trampoline, so
the stack frame can't be set up properly before it calls
trampoline_handler().
Because kretprobe handlers don't sleep, the frame pointer doesn't *have*
to be accurate in the trampoline. So it's ok to tell objtool to ignore
it. This results in no actual changes to the generated code.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Bernd Petrovitsch <bernd@petrovitsch.priv.at>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Chris J Arges <chris.j.arges@canonical.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Pedro Alves <palves@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/7eaf37de52456ff822ffc86b928edb5d48a40ef1.1456719558.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Add a new macro, STACK_FRAME_NON_STANDARD(), which is used to denote a
function which does something unusual related to its stack frame. Use
of the macro prevents objtool from emitting a false positive warning.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Bernd Petrovitsch <bernd@petrovitsch.priv.at>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Chris J Arges <chris.j.arges@canonical.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Pedro Alves <palves@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/34487a17b23dba43c50941599d47054a9584b219.1456719558.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Code which runs outside the kernel's normal mode of operation often does
unusual things which can cause a static analysis tool like objtool to
emit false positive warnings:
- boot image
- vdso image
- relocation
- realmode
- efi
- head
- purgatory
- modpost
Set OBJECT_FILES_NON_STANDARD for their related files and directories,
which will tell objtool to skip checking them. It's ok to skip them
because they don't affect runtime stack traces.
Also skip the following code which does the right thing with respect to
frame pointers, but is too "special" to be validated by a tool:
- entry
- mcount
Also skip the test_nx module because it modifies its exception handling
table at runtime, which objtool can't understand. Fortunately it's
just a test module so it doesn't matter much.
Currently objtool is the only user of OBJECT_FILES_NON_STANDARD, but it
might eventually be useful for other tools.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Bernd Petrovitsch <bernd@petrovitsch.priv.at>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Chris J Arges <chris.j.arges@canonical.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Pedro Alves <palves@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/366c080e3844e8a5b6a0327dc7e8c2b90ca3baeb.1456719558.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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table format
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
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Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
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Signed-off-by: Adam Buchbinder <adam.buchbinder@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: trivial@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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The kretprobe_trampoline_holder() wrapper around kretprobe_trampoline()
isn't used anywhere and adds some unnecessary frame pointer instructions
which never execute. Instead, just make kretprobe_trampoline() a proper
ELF function.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Bernd Petrovitsch <bernd@petrovitsch.priv.at>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Chris J Arges <chris.j.arges@canonical.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Pedro Alves <palves@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/92d921b102fb865a7c254cfde9e4a0a72b9a781e.1453405861.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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do_suspend_lowlevel() is a callable non-leaf function which doesn't
honor CONFIG_FRAME_POINTER, which can result in bad stack traces.
Create a stack frame for it when CONFIG_FRAME_POINTER is enabled.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
Acked-by: Pavel Machek <pavel@ucw.cz>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Bernd Petrovitsch <bernd@petrovitsch.priv.at>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Chris J Arges <chris.j.arges@canonical.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Len Brown <len.brown@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Pedro Alves <palves@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/7383d87dd40a460e0d757a0793498b9d06a7ee0d.1453405861.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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vide() is a callable function, but is missing the ELF function type,
which confuses tools like stacktool.
Properly annotate it to be a callable function. The generated code is
unchanged.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-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: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Bernd Petrovitsch <bernd@petrovitsch.priv.at>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Chris J Arges <chris.j.arges@canonical.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Pedro Alves <palves@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/a324095f5c9390ff39b15b4562ea1bbeda1a8282.1453405861.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Conflicts:
drivers/net/phy/bcm7xxx.c
drivers/net/phy/marvell.c
drivers/net/vxlan.c
All three conflicts were cases of simple overlapping changes.
Signed-off-by: David S. Miller <davem@davemloft.net>
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This removes the CONFIG_DEBUG_RODATA option and makes it always enabled.
This simplifies the code and also makes it clearer that read-only mapped
memory is just as fundamental a security feature in kernel-space as it is
in user-space.
Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Brown <david.brown@linaro.org>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Emese Revfy <re.emese@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathias Krause <minipli@googlemail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: PaX Team <pageexec@freemail.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kernel-hardening@lists.openwall.com
Cc: linux-arch <linux-arch@vger.kernel.org>
Link: http://lkml.kernel.org/r/1455748879-21872-4-git-send-email-keescook@chromium.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
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It's simpler to look at the topology mask than iterating over all online cpus
to find a cpu on the same package.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
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. avoid walking the stack when there is no room left in the buffer
. generalize get_perf_callchain() to be called from bpf helper
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Protection keys provide new page-based protection in hardware.
But, they have an interesting attribute: they only affect data
accesses and never affect instruction fetches. That means that
if we set up some memory which is set as "access-disabled" via
protection keys, we can still execute from it.
This patch uses protection keys to set up mappings to do just that.
If a user calls:
mmap(..., PROT_EXEC);
or
mprotect(ptr, sz, PROT_EXEC);
(note PROT_EXEC-only without PROT_READ/WRITE), the kernel will
notice this, and set a special protection key on the memory. It
also sets the appropriate bits in the Protection Keys User Rights
(PKRU) register so that the memory becomes unreadable and
unwritable.
I haven't found any userspace that does this today. With this
facility in place, we expect userspace to move to use it
eventually. Userspace _could_ start doing this today. Any
PROT_EXEC calls get converted to PROT_READ inside the kernel, and
would transparently be upgraded to "true" PROT_EXEC with this
code. IOW, userspace never has to do any PROT_EXEC runtime
detection.
This feature provides enhanced protection against leaking
executable memory contents. This helps thwart attacks which are
attempting to find ROP gadgets on the fly.
But, the security provided by this approach is not comprehensive.
The PKRU register which controls access permissions is a normal
user register writable from unprivileged userspace. An attacker
who can execute the 'wrpkru' instruction can easily disable the
protection provided by this feature.
The protection key that is used for execute-only support is
permanently dedicated at compile time. This is fine for now
because there is currently no API to set a protection key other
than this one.
Despite there being a constant PKRU value across the entire
system, we do not set it unless this feature is in use in a
process. That is to preserve the PKRU XSAVE 'init state',
which can lead to faster context switches.
PKRU *is* a user register and the kernel is modifying it. That
means that code doing:
pkru = rdpkru()
pkru |= 0x100;
mmap(..., PROT_EXEC);
wrpkru(pkru);
could lose the bits in PKRU that enforce execute-only
permissions. To avoid this, we suggest avoiding ever calling
mmap() or mprotect() when the PKRU value is expected to be
unstable.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Chen Gang <gang.chen.5i5j@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Hansen <dave@sr71.net>
Cc: David Hildenbrand <dahi@linux.vnet.ibm.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Piotr Kwapulinski <kwapulinski.piotr@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Vladimir Murzin <vladimir.murzin@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: keescook@google.com
Cc: linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20160212210240.CB4BB5CA@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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The Protection Key Rights for User memory (PKRU) is a 32-bit
user-accessible register. It contains two bits for each
protection key: one to write-disable (WD) access to memory
covered by the key and another to access-disable (AD).
Userspace can read/write the register with the RDPKRU and WRPKRU
instructions. But, the register is saved and restored with the
XSAVE family of instructions, which means we have to treat it
like a floating point register.
The kernel needs to write to the register if it wants to
implement execute-only memory or if it implements a system call
to change PKRU.
To do this, we need to create a 'pkru_state' buffer, read the old
contents in to it, modify it, and then tell the FPU code that
there is modified data in there so it can (possibly) move the
buffer back in to the registers.
This uses the fpu__xfeature_set_state() function that we defined
in the previous patch.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
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: Dave Hansen <dave@sr71.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20160212210236.0BE13217@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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|
We want to modify the Protection Key rights inside the kernel, so
we need to change PKRU's contents. But, if we do a plain
'wrpkru', when we return to userspace we might do an XRSTOR and
wipe out the kernel's 'wrpkru'. So, we need to go after PKRU in
the xsave buffer.
We do this by:
1. Ensuring that we have the XSAVE registers (fpregs) in the
kernel FPU buffer (fpstate)
2. Looking up the location of a given state in the buffer
3. Filling in the stat
4. Ensuring that the hardware knows that state is present there
(basically that the 'init optimization' is not in place).
5. Copying the newly-modified state back to the registers if
necessary.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
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: Dave Hansen <dave@sr71.net>
Cc: Denys Vlasenko <dvlasenk@redhat.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: Rik van Riel <riel@redhat.com>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20160212210235.5A3139BF@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
The arch-specific mm_context_t is a great place to put
protection-key allocation state.
But, we need to initialize the allocation state because pkey 0 is
always "allocated". All of the runtime initialization of
mm_context_t is done in *_ldt() manipulation functions. This
renames the existing LDT functions like this:
init_new_context() -> init_new_context_ldt()
destroy_context() -> destroy_context_ldt()
and makes init_new_context() and destroy_context() available for
generic use.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
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: Dave Hansen <dave@sr71.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20160212210234.DB34FCC5@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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This sets the bit in 'cr4' to actually enable the protection
keys feature. We also include a boot-time disable for the
feature "nopku".
Seting X86_CR4_PKE will cause the X86_FEATURE_OSPKE cpuid
bit to appear set. At this point in boot, identify_cpu()
has already run the actual CPUID instructions and populated
the "cpu features" structures. We need to go back and
re-run identify_cpu() to make sure it gets updated values.
We *could* simply re-populate the 11th word of the cpuid
data, but this is probably quick enough.
Also note that with the cpu_has() check and X86_FEATURE_PKU
present in disabled-features.h, we do not need an #ifdef
for setup_pku().
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
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: Dave Hansen <dave@sr71.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20160212210229.6708027C@viggo.jf.intel.com
[ Small readability edits. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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The protection key can now be just as important as read/write
permissions on a VMA. We need some debug mechanism to help
figure out if it is in play. smaps seems like a logical
place to expose it.
arch/x86/kernel/setup.c is a bit of a weirdo place to put
this code, but it already had seq_file.h and there was not
a much better existing place to put it.
We also use no #ifdef. If protection keys is .config'd out we
will effectively get the same function as if we used the weak
generic function.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave@sr71.net>
Cc: Dave Young <dyoung@redhat.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Salter <msalter@redhat.com>
Cc: Mark Williamson <mwilliamson@undo-software.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20160212210227.4F8EB3F8@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Protection Keys never affect kernel mappings. But, they can
affect whether the kernel will fault when it touches a user
mapping. The kernel doesn't touch user mappings without some
careful choreography and these accesses don't generally result in
oopses. But, if one does, we definitely want to have PKRU
available so we can figure out if protection keys played a role.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
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: Dave Hansen <dave@sr71.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20160212210225.BF0D4482@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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