The code to compute the virtual address of a cpa_data is duplicated;
introduce a helper before more copies happen.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
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: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tom.StDenis@amd.com
Cc: dave.hansen@intel.com
Link: http://lkml.kernel.org/r/20181203171043.229119497@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The current pageattr-test code only uses the regular range interface,
add code that also tests the array and pages interface.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
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: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tom.StDenis@amd.com
Cc: dave.hansen@intel.com
Link: http://lkml.kernel.org/r/20181203171043.162771364@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
In commit:
a7295fd53c ("x86/mm/cpa: Use flush_tlb_kernel_range()")
I misread the CAP array code and incorrectly used
tlb_flush_kernel_range(), resulting in missing TLB flushes and
consequent failures.
Instead do a full invalidate in this case -- for now.
Reported-by: StDenis, Tom <Tom.StDenis@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
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: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dave.hansen@intel.com
Fixes: a7295fd53c ("x86/mm/cpa: Use flush_tlb_kernel_range()")
Link: http://lkml.kernel.org/r/20181203171043.089868285@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
A decoy address is used by set_mce_nospec() to update the cache attributes
for a page that may contain poison (multi-bit ECC error) while attempting
to minimize the possibility of triggering a speculative access to that
page.
When reserve_memtype() is handling a decoy address it needs to convert it
to its real physical alias. The conversion, AND'ing with __PHYSICAL_MASK,
is broken for a 32-bit physical mask and reserve_memtype() is passed the
last physical page. Gert reports triggering the:
BUG_ON(start >= end);
...assertion when running a 32-bit non-PAE build on a platform that has
a driver resource at the top of physical memory:
BIOS-e820: [mem 0x00000000fff00000-0x00000000ffffffff] reserved
Given that the decoy address scheme is only targeted at 64-bit builds and
assumes that the top of physical address space is free for use as a decoy
address range, simply bypass address sanitization in the 32-bit case.
Lastly, there was no need to crash the system when this failure occurred,
and no need to crash future systems if the assumptions of decoy addresses
are ever violated. Change the BUG_ON() to a WARN() with an error return.
Fixes: 510ee090ab ("x86/mm/pat: Prepare {reserve, free}_memtype() for...")
Reported-by: Gert Robben <t2@gert.gr>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Gert Robben <t2@gert.gr>
Cc: stable@vger.kernel.org
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: platform-driver-x86@vger.kernel.org
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/154454337985.789277.12133288391664677775.stgit@dwillia2-desk3.amr.corp.intel.com
There is a guard hole at the beginning of the kernel address space, also
used by hypervisors. It occupies 16 PGD entries.
This reserved range is not defined explicitely, it is calculated relative
to other entities: direct mapping and user space ranges.
The calculation got broken by recent changes of the kernel memory layout:
LDT remap range is now mapped before direct mapping and makes the
calculation invalid.
The breakage leads to crash on Xen dom0 boot[1].
Define the reserved range explicitely. It's part of kernel ABI (hypervisors
expect it to be stable) and must not depend on changes in the rest of
kernel memory layout.
[1] https://lists.xenproject.org/archives/html/xen-devel/2018-11/msg03313.html
Fixes: d52888aa27 ("x86/mm: Move LDT remap out of KASLR region on 5-level paging")
Reported-by: Hans van Kranenburg <hans.van.kranenburg@mendix.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Hans van Kranenburg <hans.van.kranenburg@mendix.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Cc: bp@alien8.de
Cc: hpa@zytor.com
Cc: dave.hansen@linux.intel.com
Cc: luto@kernel.org
Cc: peterz@infradead.org
Cc: boris.ostrovsky@oracle.com
Cc: bhe@redhat.com
Cc: linux-mm@kvack.org
Cc: xen-devel@lists.xenproject.org
Link: https://lkml.kernel.org/r/20181130202328.65359-2-kirill.shutemov@linux.intel.com
Commit:
f77084d963 "x86/mm/pat: Disable preemption around __flush_tlb_all()"
addressed a case where __flush_tlb_all() is called without preemption
being disabled. It also left a warning to catch other cases where
preemption is not disabled.
That warning triggers for the memory hotplug path which is also used for
persistent memory enabling:
WARNING: CPU: 35 PID: 911 at ./arch/x86/include/asm/tlbflush.h:460
RIP: 0010:__flush_tlb_all+0x1b/0x3a
[..]
Call Trace:
phys_pud_init+0x29c/0x2bb
kernel_physical_mapping_init+0xfc/0x219
init_memory_mapping+0x1a5/0x3b0
arch_add_memory+0x2c/0x50
devm_memremap_pages+0x3aa/0x610
pmem_attach_disk+0x585/0x700 [nd_pmem]
Andy wondered why a path that can sleep was using __flush_tlb_all() [1]
and Dave confirmed the expectation for TLB flush is for modifying /
invalidating existing PTE entries, but not initial population [2]. Drop
the usage of __flush_tlb_all() in phys_{p4d,pud,pmd}_init() on the
expectation that this path is only ever populating empty entries for the
linear map. Note, at linear map teardown time there is a call to the
all-cpu flush_tlb_all() to invalidate the removed mappings.
[1]: https://lkml.kernel.org/r/9DFD717D-857D-493D-A606-B635D72BAC21@amacapital.net
[2]: https://lkml.kernel.org/r/749919a4-cdb1-48a3-adb4-adb81a5fa0b5@intel.com
[ mingo: Minor readability edits. ]
Suggested-by: Dave Hansen <dave.hansen@linux.intel.com>
Reported-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: <stable@vger.kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dave.hansen@intel.com
Fixes: f77084d963 ("x86/mm/pat: Disable preemption around __flush_tlb_all()")
Link: http://lkml.kernel.org/r/154395944713.32119.15611079023837132638.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The usage of __flush_tlb_all() in the kernel_physical_mapping_init()
path is not necessary. In general flushing the TLB is not required when
updating an entry from the !present state. However, to give confidence
in the future removal of TLB flushing in this path, use the new
set_pte_safe() family of helpers to assert that the !present assumption
is true in this path.
[ mingo: Minor readability edits. ]
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Suggested-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
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: Rik van Riel <riel@surriel.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/154395944177.32119.8524957429632012270.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The IBPB speculation barrier is issued from switch_mm() when the kernel
switches to a user space task with a different mm than the user space task
which ran last on the same CPU.
An additional optimization is to avoid IBPB when the incoming task can be
ptraced by the outgoing task. This optimization only works when switching
directly between two user space tasks. When switching from a kernel task to
a user space task the optimization fails because the previous task cannot
be accessed anymore. So for quite some scenarios the optimization is just
adding overhead.
The upcoming conditional IBPB support will issue IBPB only for user space
tasks which have the TIF_SPEC_IB bit set. This requires to handle the
following cases:
1) Switch from a user space task (potential attacker) which has
TIF_SPEC_IB set to a user space task (potential victim) which has
TIF_SPEC_IB not set.
2) Switch from a user space task (potential attacker) which has
TIF_SPEC_IB not set to a user space task (potential victim) which has
TIF_SPEC_IB set.
This needs to be optimized for the case where the IBPB can be avoided when
only kernel threads ran in between user space tasks which belong to the
same process.
The current check whether two tasks belong to the same context is using the
tasks context id. While correct, it's simpler to use the mm pointer because
it allows to mangle the TIF_SPEC_IB bit into it. The context id based
mechanism requires extra storage, which creates worse code.
When a task is scheduled out its TIF_SPEC_IB bit is mangled as bit 0 into
the per CPU storage which is used to track the last user space mm which was
running on a CPU. This bit can be used together with the TIF_SPEC_IB bit of
the incoming task to make the decision whether IBPB needs to be issued or
not to cover the two cases above.
As conditional IBPB is going to be the default, remove the dubious ptrace
check for the IBPB always case and simply issue IBPB always when the
process changes.
Move the storage to a different place in the struct as the original one
created a hole.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Woodhouse <dwmw@amazon.co.uk>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Casey Schaufler <casey.schaufler@intel.com>
Cc: Asit Mallick <asit.k.mallick@intel.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Jon Masters <jcm@redhat.com>
Cc: Waiman Long <longman9394@gmail.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Dave Stewart <david.c.stewart@intel.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20181125185005.466447057@linutronix.de
- Make the oops messages a bit less scary (don't mention 'HW errors')
- Turn 'PROT USER' (which is visually easily confused with PROT_USER)
into individual bit descriptors: "[PROT] [USER]".
This also makes "[normal kernel read fault]" more apparent.
- De-abbreviate variables to make the code easier to read
- Use vertical alignment where appropriate.
- Add comment about string size limits and the helper function.
- Remove unnecessary line breaks.
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: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
One of Linus' favorite hobbies seems to be looking at OOPSes and
decoding the error code in his head. This is not one of my favorite
hobbies :)
Teach the page fault OOPS hander to decode the error code. If it's
a !USER fault from user mode, print an explicit note to that effect
and print out the addresses of various tables that might cause such
an error.
With this patch applied, if I intentionally point the LDT at 0x0 and
run the x86 selftests, I get:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
HW error: normal kernel read fault
This was a system access from user code
IDT: 0xfffffe0000000000 (limit=0xfff) GDT: 0xfffffe0000001000 (limit=0x7f)
LDTR: 0x50 -- base=0x0 limit=0xfff7
TR: 0x40 -- base=0xfffffe0000003000 limit=0x206f
PGD 800000000456e067 P4D 800000000456e067 PUD 4623067 PMD 0
SMP PTI
CPU: 0 PID: 153 Comm: ldt_gdt_64 Not tainted 4.19.0+ #1317
Hardware name: ...
RIP: 0033:0x401454
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/11212acb25980cd1b3030875cd9502414fbb214d.1542841400.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This avoids a situation in which we attempt to apply various fixups
that are not intended to handle implicit supervisor accesses from
user mode if we screw up in a way that causes this type of fault.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/9999f151d72ff352265f3274c5ab3a4105090f49.1542841400.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
All of the fault handling code now corrently checks user_mode(regs)
as needed, and nothing depends on the X86_PF_USER bit being munged.
Get rid of the sw_error code and use hw_error_code everywhere.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/078f5b8ae6e8c79ff8ee7345b5c476c45003e5ac.1542841400.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The fault handling code sets the cr2, trap_nr, and error_code fields
in thread_struct before OOPSing. No one reads those fields during
an OOPS, so remove the code to set them.
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: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/d418022aa0fad9cb40467aa7acaf4e95be50ee96.1542667307.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The error code in a page fault on a kernel address indicates
whether that address is mapped, which should not be revealed in a signal.
The normal code path for a page fault on a kernel address sanitizes the bit,
but the paths for vsyscall emulation and SIGBUS do not. Both are
harmless, but for subtle reasons. SIGBUS is never sent for a kernel
address, and vsyscall emulation will never fault on a kernel address
per se because it will fail an access_ok() check instead.
Make the code more robust by adding a helper that sets the relevant
fields and sanitizing the error code in the helper. This also
cleans up the code -- we had three copies of roughly the same thing.
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: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/b31159bd55bd0c4fa061a20dfd6c429c094bebaa.1542667307.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
__bad_area_nosemaphore() currently checks the X86_PF_USER bit in the
error code to decide whether to send a signal or to treat the fault
as a kernel error. This can cause somewhat erratic behavior. The
straightforward cases where the CPL agrees with the hardware USER
bit are all correct, but the other cases are confusing.
- A user instruction accessing a kernel address with supervisor
privilege (e.g. a descriptor table access failed). The USER bit
will be clear, and we OOPS. This is correct, because it indicates
a kernel bug, not a user error.
- A user instruction accessing a user address with supervisor
privilege (e.g. a descriptor table was incorrectly pointing at
user memory). __bad_area_nosemaphore() will be passed a modified
error code with the user bit set, and we will send a signal.
Sending the signal will work (because the regs and the entry
frame genuinely come from user mode), but we really ought to
OOPS, as this event indicates a severe kernel bug.
- A kernel instruction with user privilege (i.e. WRUSS). This
should OOPS or get fixed up. The current code would instead try
send a signal and malfunction.
Change the logic: a signal should be sent if the faulting context is
user mode *and* the access has user privilege. Otherwise it's
either a kernel mode fault or a failed implicit access, either of
which should end up in no_context().
Note to -stable maintainers: don't backport this unless you backport
CET. The bug it fixes is unobservable in current kernels unless
something is extremely wrong.
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: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/10e509c43893170e262e82027ea399130ae81159.1542667307.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Currently, if a user program somehow triggers an implicit supervisor
access to a user address (e.g. if the kernel somehow sets LDTR to a
user address), it will be incorrectly detected as a SMAP violation
if AC is clear and SMAP is enabled. This is incorrect -- the error
has nothing to do with SMAP. Fix the condition so that only
accesses with the hardware USER bit set are diagnosed as SMAP
violations.
With the logic fixed, an implicit supervisor access to a user address
will hit the code lower in the function that is intended to handle it
even if SMAP is enabled. That logic is still a bit buggy, and later
patches will clean it up.
I *think* this code is still correct for WRUSS, and I've added a
comment to that effect.
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: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/d1d1b2e66ef31f884dba172084486ea9423ddcdb.1542667307.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
smap_violation() has a single caller, and the contents are a bit
nonsensical. I'm going to fix it, but first let's fold it into its
caller for ease of comprehension.
In this particular case, the user_mode(regs) check is incorrect --
it will cause false positives in the case of a user-initiated
kernel-privileged access.
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: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/806c366f6ca861152398ce2c01744d59d9aceb6d.1542667307.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Add X86_FEATURE_SMAP to the disabled features mask as appropriate
and use cpu_feature_enabled() in the fault code. This lets us get
rid of a redundant IS_ENABLED(CONFIG_X86_SMAP).
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: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/fe93332eded3d702f0b0b4cf83928d6830739ba3.1542667307.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The fault-handling code that takes mmap_sem needs to avoid a
deadlock that could occur if the kernel took a bad (OOPS-worthy)
page fault on a user address while holding mmap_sem. This can only
happen if the faulting instruction was in the kernel
(i.e. user_mode(regs)). Rather than checking the sw_error_code
(which will have the USER bit set if the fault was a USER-permission
access *or* if user_mode(regs)), just check user_mode(regs)
directly.
The old code would have malfunctioned if the kernel executed a bogus
WRUSS instruction while holding mmap_sem. Fortunately, that is
extremely unlikely in current kernels, which don't use WRUSS.
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: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/4b89b542e8ceba9bd6abde2f386afed6d99244a9.1542667307.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The current x86 page fault handler allows stack access below the stack
pointer if it is no more than 64k+256 bytes. Any access beyond the 64k+
limit will cause a segmentation fault.
The gcc -fstack-check option generates code to probe the stack for
large stack allocation to see if the stack is accessible. The newer gcc
does that while updating the %rsp simultaneously. Older gcc's like gcc4
doesn't do that. As a result, an application compiled with an old gcc
and the -fstack-check option may fail to start at all:
$ cat test.c
int main() {
char tmp[1024*128];
printf("### ok\n");
return 0;
}
$ gcc -fstack-check -g -o test test.c
$ ./test
Segmentation fault
The old binary was working in older kernels where expand_stack() was
somehow called before the check. But it is not working in newer kernels.
Besides, the 64k+ limit check is kind of crude and will not catch a
lot of mistakes that userspace applications may be misbehaving anyway.
I think the kernel isn't the right place for this kind of tests. We
should leave it to userspace instrumentation tools to perform them.
The 64k+ limit check is now removed to just let expand_stack() decide
if a segmentation fault should happen, when the RLIMIT_STACK limit is
exceeded, for example.
Signed-off-by: Waiman Long <longman@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1541535149-31963-1-git-send-email-longman@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The result of in_compat_syscall() can be pictured as:
x86 platform:
---------------------------------------------------
| Arch\syscall | 64-bit | ia32 | x32 |
|-------------------------------------------------|
| x86_64 | false | true | true |
|-------------------------------------------------|
| i686 | | <true> | |
---------------------------------------------------
Other platforms:
-------------------------------------------
| Arch\syscall | 64-bit | compat |
|-----------------------------------------|
| 64-bit | false | true |
|-----------------------------------------|
| 32-bit(?) | | <false> |
-------------------------------------------
As seen, the result of in_compat_syscall() on generic 32-bit platform
differs from i686.
There is no reason for in_compat_syscall() == true on native i686. It also
easy to misread code if the result on native 32-bit platform differs
between arches.
Because of that non arch-specific code has many places with:
if (IS_ENABLED(CONFIG_COMPAT) && in_compat_syscall())
in different variations.
It looks-like the only non-x86 code which uses in_compat_syscall() not
under CONFIG_COMPAT guard is in amd/amdkfd. But according to the commit
a18069c132 ("amdkfd: Disable support for 32-bit user processes"), it
actually should be disabled on native i686.
Rename in_compat_syscall() to in_32bit_syscall() for x86-specific code
and make in_compat_syscall() false under !CONFIG_COMPAT.
A follow on patch will clean up generic users which were forced to check
IS_ENABLED(CONFIG_COMPAT) with in_compat_syscall().
Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-efi@vger.kernel.org
Cc: netdev@vger.kernel.org
Link: https://lkml.kernel.org/r/20181012134253.23266-2-dima@arista.com
Move remaining definitions and declarations from include/linux/bootmem.h
into include/linux/memblock.h and remove the redundant header.
The includes were replaced with the semantic patch below and then
semi-automated removal of duplicated '#include <linux/memblock.h>
@@
@@
- #include <linux/bootmem.h>
+ #include <linux/memblock.h>
[sfr@canb.auug.org.au: dma-direct: fix up for the removal of linux/bootmem.h]
Link: http://lkml.kernel.org/r/20181002185342.133d1680@canb.auug.org.au
[sfr@canb.auug.org.au: powerpc: fix up for removal of linux/bootmem.h]
Link: http://lkml.kernel.org/r/20181005161406.73ef8727@canb.auug.org.au
[sfr@canb.auug.org.au: x86/kaslr, ACPI/NUMA: fix for linux/bootmem.h removal]
Link: http://lkml.kernel.org/r/20181008190341.5e396491@canb.auug.org.au
Link: http://lkml.kernel.org/r/1536927045-23536-30-git-send-email-rppt@linux.vnet.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Serge Semin <fancer.lancer@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The alloc_bootmem_pages() function allocates PAGE_SIZE aligned memory.
memblock_alloc() with alignment set to PAGE_SIZE does exactly the same
thing.
The conversion is done using the following semantic patch:
@@
expression e;
@@
- alloc_bootmem_pages(e)
+ memblock_alloc(e, PAGE_SIZE)
Link: http://lkml.kernel.org/r/1536927045-23536-20-git-send-email-rppt@linux.vnet.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Serge Semin <fancer.lancer@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Make it explicit that the caller gets a physical address rather than a
virtual one.
This will also allow using meblock_alloc prefix for memblock allocations
returning virtual address, which is done in the following patches.
The conversion is done using the following semantic patch:
@@
expression e1, e2, e3;
@@
(
- memblock_alloc(e1, e2)
+ memblock_phys_alloc(e1, e2)
|
- memblock_alloc_nid(e1, e2, e3)
+ memblock_phys_alloc_nid(e1, e2, e3)
|
- memblock_alloc_try_nid(e1, e2, e3)
+ memblock_phys_alloc_try_nid(e1, e2, e3)
)
Link: http://lkml.kernel.org/r/1536927045-23536-7-git-send-email-rppt@linux.vnet.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Serge Semin <fancer.lancer@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The numa_emulation() routine in the 'uniform' case walks through all the
physical 'memblk' instances and divides them into N emulated nodes with
split_nodes_size_interleave_uniform(). As each physical node is consumed it
is removed from the physical memblk array in the numa_remove_memblk_from()
helper.
Since split_nodes_size_interleave_uniform() handles advancing the array as
the 'memblk' is consumed it is expected that the base of the array is
always specified as the argument.
Otherwise, on multi-socket (> 2) configurations the uniform-split
capability can generate an invalid numa configuration leading to boot
failures with signatures like the following:
rcu: INFO: rcu_sched detected stalls on CPUs/tasks:
Sending NMI from CPU 0 to CPUs 2:
NMI backtrace for cpu 2
CPU: 2 PID: 1332 Comm: pgdatinit0 Not tainted 4.19.0-rc8-next-20181019-baseline #59
RIP: 0010:__init_single_page.isra.74+0x81/0x90
[..]
Call Trace:
deferred_init_pages+0xaa/0xe3
deferred_init_memmap+0x18f/0x318
kthread+0xf8/0x130
? deferred_free_pages.isra.105+0xc9/0xc9
? kthread_stop+0x110/0x110
ret_from_fork+0x35/0x40
Fixes: 1f6a2c6d9f121 ("x86/numa_emulation: Introduce uniform split capability")
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/154049911459.2685845.9210186007479774286.stgit@dwillia2-desk3.amr.corp.intel.com
The WARN_ON_ONCE(__read_cr3() != build_cr3()) in switch_mm_irqs_off()
triggers every once in a while during a snapshotted system upgrade.
The warning triggers since commit decab0888e ("x86/mm: Remove
preempt_disable/enable() from __native_flush_tlb()"). The callchain is:
get_page_from_freelist() -> post_alloc_hook() -> __kernel_map_pages()
with CONFIG_DEBUG_PAGEALLOC enabled.
Disable preemption during CR3 reset / __flush_tlb_all() and add a comment
why preemption has to be disabled so it won't be removed accidentaly.
Add another preemptible() check in __flush_tlb_all() to catch callers with
enabled preemption when PGE is enabled, because PGE enabled does not
trigger the warning in __native_flush_tlb(). Suggested by Andy Lutomirski.
Fixes: decab0888e ("x86/mm: Remove preempt_disable/enable() from __native_flush_tlb()")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20181017103432.zgv46nlu3hc7k4rq@linutronix.de
Pull siginfo updates from Eric Biederman:
"I have been slowly sorting out siginfo and this is the culmination of
that work.
The primary result is in several ways the signal infrastructure has
been made less error prone. The code has been updated so that manually
specifying SEND_SIG_FORCED is never necessary. The conversion to the
new siginfo sending functions is now complete, which makes it
difficult to send a signal without filling in the proper siginfo
fields.
At the tail end of the patchset comes the optimization of decreasing
the size of struct siginfo in the kernel from 128 bytes to about 48
bytes on 64bit. The fundamental observation that enables this is by
definition none of the known ways to use struct siginfo uses the extra
bytes.
This comes at the cost of a small user space observable difference.
For the rare case of siginfo being injected into the kernel only what
can be copied into kernel_siginfo is delivered to the destination, the
rest of the bytes are set to 0. For cases where the signal and the
si_code are known this is safe, because we know those bytes are not
used. For cases where the signal and si_code combination is unknown
the bits that won't fit into struct kernel_siginfo are tested to
verify they are zero, and the send fails if they are not.
I made an extensive search through userspace code and I could not find
anything that would break because of the above change. If it turns out
I did break something it will take just the revert of a single change
to restore kernel_siginfo to the same size as userspace siginfo.
Testing did reveal dependencies on preferring the signo passed to
sigqueueinfo over si->signo, so bit the bullet and added the
complexity necessary to handle that case.
Testing also revealed bad things can happen if a negative signal
number is passed into the system calls. Something no sane application
will do but something a malicious program or a fuzzer might do. So I
have fixed the code that performs the bounds checks to ensure negative
signal numbers are handled"
* 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (80 commits)
signal: Guard against negative signal numbers in copy_siginfo_from_user32
signal: Guard against negative signal numbers in copy_siginfo_from_user
signal: In sigqueueinfo prefer sig not si_signo
signal: Use a smaller struct siginfo in the kernel
signal: Distinguish between kernel_siginfo and siginfo
signal: Introduce copy_siginfo_from_user and use it's return value
signal: Remove the need for __ARCH_SI_PREABLE_SIZE and SI_PAD_SIZE
signal: Fail sigqueueinfo if si_signo != sig
signal/sparc: Move EMT_TAGOVF into the generic siginfo.h
signal/unicore32: Use force_sig_fault where appropriate
signal/unicore32: Generate siginfo in ucs32_notify_die
signal/unicore32: Use send_sig_fault where appropriate
signal/arc: Use force_sig_fault where appropriate
signal/arc: Push siginfo generation into unhandled_exception
signal/ia64: Use force_sig_fault where appropriate
signal/ia64: Use the force_sig(SIGSEGV,...) in ia64_rt_sigreturn
signal/ia64: Use the generic force_sigsegv in setup_frame
signal/arm/kvm: Use send_sig_mceerr
signal/arm: Use send_sig_fault where appropriate
signal/arm: Use force_sig_fault where appropriate
...
Pull x86 pti updates from Ingo Molnar:
"The main changes:
- Make the IBPB barrier more strict and add STIBP support (Jiri
Kosina)
- Micro-optimize and clean up the entry code (Andy Lutomirski)
- ... plus misc other fixes"
* 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/speculation: Propagate information about RSB filling mitigation to sysfs
x86/speculation: Enable cross-hyperthread spectre v2 STIBP mitigation
x86/speculation: Apply IBPB more strictly to avoid cross-process data leak
x86/speculation: Add RETPOLINE_AMD support to the inline asm CALL_NOSPEC variant
x86/CPU: Fix unused variable warning when !CONFIG_IA32_EMULATION
x86/pti/64: Remove the SYSCALL64 entry trampoline
x86/entry/64: Use the TSS sp2 slot for SYSCALL/SYSRET scratch space
x86/entry/64: Document idtentry
Pull x86 paravirt updates from Ingo Molnar:
"Two main changes:
- Remove no longer used parts of the paravirt infrastructure and put
large quantities of paravirt ops under a new config option
PARAVIRT_XXL=y, which is selected by XEN_PV only. (Joergen Gross)
- Enable PV spinlocks on Hyperv (Yi Sun)"
* 'x86-paravirt-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/hyperv: Enable PV qspinlock for Hyper-V
x86/hyperv: Add GUEST_IDLE_MSR support
x86/paravirt: Clean up native_patch()
x86/paravirt: Prevent redefinition of SAVE_FLAGS macro
x86/xen: Make xen_reservation_lock static
x86/paravirt: Remove unneeded mmu related paravirt ops bits
x86/paravirt: Move the Xen-only pv_mmu_ops under the PARAVIRT_XXL umbrella
x86/paravirt: Move the pv_irq_ops under the PARAVIRT_XXL umbrella
x86/paravirt: Move the Xen-only pv_cpu_ops under the PARAVIRT_XXL umbrella
x86/paravirt: Move items in pv_info under PARAVIRT_XXL umbrella
x86/paravirt: Introduce new config option PARAVIRT_XXL
x86/paravirt: Remove unused paravirt bits
x86/paravirt: Use a single ops structure
x86/paravirt: Remove clobbers from struct paravirt_patch_site
x86/paravirt: Remove clobbers parameter from paravirt patch functions
x86/paravirt: Make paravirt_patch_call() and paravirt_patch_jmp() static
x86/xen: Add SPDX identifier in arch/x86/xen files
x86/xen: Link platform-pci-unplug.o only if CONFIG_XEN_PVHVM
x86/xen: Move pv specific parts of arch/x86/xen/mmu.c to mmu_pv.c
x86/xen: Move pv irq related functions under CONFIG_XEN_PV umbrella
Pull x86 mm updates from Ingo Molnar:
"Lots of changes in this cycle:
- Lots of CPA (change page attribute) optimizations and related
cleanups (Thomas Gleixner, Peter Zijstra)
- Make lazy TLB mode even lazier (Rik van Riel)
- Fault handler cleanups and improvements (Dave Hansen)
- kdump, vmcore: Enable kdumping encrypted memory with AMD SME
enabled (Lianbo Jiang)
- Clean up VM layout documentation (Baoquan He, Ingo Molnar)
- ... plus misc other fixes and enhancements"
* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (51 commits)
x86/stackprotector: Remove the call to boot_init_stack_canary() from cpu_startup_entry()
x86/mm: Kill stray kernel fault handling comment
x86/mm: Do not warn about PCI BIOS W+X mappings
resource: Clean it up a bit
resource: Fix find_next_iomem_res() iteration issue
resource: Include resource end in walk_*() interfaces
x86/kexec: Correct KEXEC_BACKUP_SRC_END off-by-one error
x86/mm: Remove spurious fault pkey check
x86/mm/vsyscall: Consider vsyscall page part of user address space
x86/mm: Add vsyscall address helper
x86/mm: Fix exception table comments
x86/mm: Add clarifying comments for user addr space
x86/mm: Break out user address space handling
x86/mm: Break out kernel address space handling
x86/mm: Clarify hardware vs. software "error_code"
x86/mm/tlb: Make lazy TLB mode lazier
x86/mm/tlb: Add freed_tables element to flush_tlb_info
x86/mm/tlb: Add freed_tables argument to flush_tlb_mm_range
smp,cpumask: introduce on_each_cpu_cond_mask
smp: use __cpumask_set_cpu in on_each_cpu_cond
...
Pull locking and misc x86 updates from Ingo Molnar:
"Lots of changes in this cycle - in part because locking/core attracted
a number of related x86 low level work which was easier to handle in a
single tree:
- Linux Kernel Memory Consistency Model updates (Alan Stern, Paul E.
McKenney, Andrea Parri)
- lockdep scalability improvements and micro-optimizations (Waiman
Long)
- rwsem improvements (Waiman Long)
- spinlock micro-optimization (Matthew Wilcox)
- qspinlocks: Provide a liveness guarantee (more fairness) on x86.
(Peter Zijlstra)
- Add support for relative references in jump tables on arm64, x86
and s390 to optimize jump labels (Ard Biesheuvel, Heiko Carstens)
- Be a lot less permissive on weird (kernel address) uaccess faults
on x86: BUG() when uaccess helpers fault on kernel addresses (Jann
Horn)
- macrofy x86 asm statements to un-confuse the GCC inliner. (Nadav
Amit)
- ... and a handful of other smaller changes as well"
* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (57 commits)
locking/lockdep: Make global debug_locks* variables read-mostly
locking/lockdep: Fix debug_locks off performance problem
locking/pvqspinlock: Extend node size when pvqspinlock is configured
locking/qspinlock_stat: Count instances of nested lock slowpaths
locking/qspinlock, x86: Provide liveness guarantee
x86/asm: 'Simplify' GEN_*_RMWcc() macros
locking/qspinlock: Rework some comments
locking/qspinlock: Re-order code
locking/lockdep: Remove duplicated 'lock_class_ops' percpu array
x86/defconfig: Enable CONFIG_USB_XHCI_HCD=y
futex: Replace spin_is_locked() with lockdep
locking/lockdep: Make class->ops a percpu counter and move it under CONFIG_DEBUG_LOCKDEP=y
x86/jump-labels: Macrofy inline assembly code to work around GCC inlining bugs
x86/cpufeature: Macrofy inline assembly code to work around GCC inlining bugs
x86/extable: Macrofy inline assembly code to work around GCC inlining bugs
x86/paravirt: Work around GCC inlining bugs when compiling paravirt ops
x86/bug: Macrofy the BUG table section handling, to work around GCC inlining bugs
x86/alternatives: Macrofy lock prefixes to work around GCC inlining bugs
x86/refcount: Work around GCC inlining bug
x86/objtool: Use asm macros to work around GCC inlining bugs
...
Pull EFI updates from Ingo Molnar:
"The main changes are:
- Add support for enlisting the help of the EFI firmware to create
memory reservations that persist across kexec.
- Add page fault handling to the runtime services support code on x86
so we can more gracefully recover from buggy EFI firmware.
- Fix command line handling on x86 for the boot path that omits the
stub's PE/COFF entry point.
- Other assorted fixes and updates"
* 'efi-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86: boot: Fix EFI stub alignment
efi/x86: Call efi_parse_options() from efi_main()
efi/x86: earlyprintk - Add 64bit efi fb address support
efi/x86: drop task_lock() from efi_switch_mm()
efi/x86: Handle page faults occurring while running EFI runtime services
efi: Make efi_rts_work accessible to efi page fault handler
efi/efi_test: add exporting ResetSystem runtime service
efi/libstub: arm: support building with clang
efi: add API to reserve memory persistently across kexec reboot
efi/arm: libstub: add a root memreserve config table
efi: honour memory reservations passed via a linux specific config table
I originally had matching user and kernel comments, but the kernel
one got improved. Some errant conflict resolution kicked the commment
somewhere wrong. Kill it.
Reported-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Jann Horn <jannh@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: aa37c51b94 ("x86/mm: Break out user address space handling")
Link: http://lkml.kernel.org/r/20181019140842.12F929FA@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
PCI BIOS requires the BIOS area 0x0A0000-0x0FFFFFF to be mapped W+X for
various legacy reasons. When CONFIG_DEBUG_WX is enabled, this triggers the
WX warning, but this is misleading because the mapping is required and is
not a result of an accidental oversight.
Prevent the full warning when PCI BIOS is enabled and the detected WX
mapping is in the BIOS area. Just emit a pr_warn() which denotes the
fact. This is partially duplicating the info which the PCI BIOS code emits
when it maps the area as executable, but that info is not in the context of
the WX checking output.
Remove the extra %p printout in the WARN_ONCE() while at it. %pS is enough.
Reported-by: Paul Menzel <pmenzel@molgen.mpg.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Borislav Petkov <bp@suse.de>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1810082151160.2455@nanos.tec.linutronix.de
Spurious faults only ever occur in the kernel's address space. They
are also constrained specifically to faults with one of these error codes:
X86_PF_WRITE | X86_PF_PROT
X86_PF_INSTR | X86_PF_PROT
So, it's never even possible to reach spurious_kernel_fault_check() with
X86_PF_PK set.
In addition, the kernel's address space never has pages with user-mode
protections. Protection Keys are only enforced on pages with user-mode
protection.
This gives us lots of reasons to not check for protection keys in our
sprurious kernel fault handling.
But, let's also add some warnings to ensure that these assumptions about
protection keys hold true.
Cc: x86@kernel.org
Cc: Jann Horn <jannh@google.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180928160231.243A0D6A@viggo.jf.intel.com
The vsyscall page is weird. It is in what is traditionally part of
the kernel address space. But, it has user permissions and we handle
faults on it like we would on a user page: interrupts on.
Right now, we handle vsyscall emulation in the "bad_area" code, which
is used for both user-address-space and kernel-address-space faults.
Move the handling to the user-address-space code *only* and ensure we
get there by "excluding" the vsyscall page from the kernel address
space via a check in fault_in_kernel_space().
Since the fault_in_kernel_space() check is used on 32-bit, also add a
64-bit check to make it clear we only use this path on 64-bit. Also
move the unlikely() to be in is_vsyscall_vaddr() itself.
This helps clean up the kernel fault handling path by removing a case
that can happen in normal[1] operation. (Yeah, yeah, we can argue
about the vsyscall page being "normal" or not.) This also makes
sanity checks easier, like the "we never take pkey faults in the
kernel address space" check in the next patch.
Cc: x86@kernel.org
Cc: Jann Horn <jannh@google.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180928160230.6E9336EE@viggo.jf.intel.com
We will shortly be using this check in two locations. Put it in
a helper before we do so.
Let's also insert PAGE_MASK instead of the open-coded ~0xfff.
It is easier to read and also more obviously correct considering
the implicit type conversion that has to happen when it is not
an implicit 'unsigned long'.
Cc: x86@kernel.org
Cc: Jann Horn <jannh@google.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180928160228.C593509B@viggo.jf.intel.com
The comments here are wrong. They are too absolute about where
faults can occur when running in the kernel. The comments are
also a bit hard to match up with the code.
Trim down the comments, and make them more precise.
Also add a comment explaining why we are doing the
bad_area_nosemaphore() path here.
Cc: x86@kernel.org
Cc: Jann Horn <jannh@google.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180928160227.077DDD7A@viggo.jf.intel.com
The SMAP and Reserved checking do not have nice comments. Add
some to clarify and make it match everything else.
Cc: x86@kernel.org
Cc: Jann Horn <jannh@google.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180928160225.FFD44B8D@viggo.jf.intel.com
The last patch broke out kernel address space handing into its own
helper. Now, do the same for user address space handling.
Cc: x86@kernel.org
Cc: Jann Horn <jannh@google.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180928160223.9C4F6440@viggo.jf.intel.com
The page fault handler (__do_page_fault()) basically has two sections:
one for handling faults in the kernel portion of the address space
and another for faults in the user portion of the address space.
But, these two parts don't stick out that well. Let's make that more
clear from code separation and naming. Pull kernel fault
handling into its own helper, and reflect that naming by renaming
spurious_fault() -> spurious_kernel_fault().
Also, rewrite the vmalloc() handling comment a bit. It was a bit
stale and also glossed over the reserved bit handling.
Cc: x86@kernel.org
Cc: Jann Horn <jannh@google.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180928160222.401F4E10@viggo.jf.intel.com
We pass around a variable called "error_code" all around the page
fault code. Sounds simple enough, especially since "error_code" looks
like it exactly matches the values that the hardware gives us on the
stack to report the page fault error code (PFEC in SDM parlance).
But, that's not how it works.
For part of the page fault handler, "error_code" does exactly match
PFEC. But, during later parts, it diverges and starts to mean
something a bit different.
Give it two names for its two jobs.
The place it diverges is also really screwy. It's only in a spot
where the hardware tells us we have kernel-mode access that occurred
while we were in usermode accessing user-controlled address space.
Add a warning in there.
Cc: x86@kernel.org
Cc: Jann Horn <jannh@google.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180928160220.4A2272C9@viggo.jf.intel.com
Lazy TLB mode can result in an idle CPU being woken up by a TLB flush,
when all it really needs to do is reload %CR3 at the next context switch,
assuming no page table pages got freed.
Memory ordering is used to prevent race conditions between switch_mm_irqs_off,
which checks whether .tlb_gen changed, and the TLB invalidation code, which
increments .tlb_gen whenever page table entries get invalidated.
The atomic increment in inc_mm_tlb_gen is its own barrier; the context
switch code adds an explicit barrier between reading tlbstate.is_lazy and
next->context.tlb_gen.
CPUs in lazy TLB mode remain part of the mm_cpumask(mm), both because
that allows TLB flush IPIs to be sent at page table freeing time, and
because the cache line bouncing on the mm_cpumask(mm) was responsible
for about half the CPU use in switch_mm_irqs_off().
We can change native_flush_tlb_others() without touching other
(paravirt) implementations of flush_tlb_others() because we'll be
flushing less. The existing implementations flush more and are
therefore still correct.
Cc: npiggin@gmail.com
Cc: mingo@kernel.org
Cc: will.deacon@arm.com
Cc: kernel-team@fb.com
Cc: luto@kernel.org
Cc: hpa@zytor.com
Tested-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Rik van Riel <riel@surriel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180926035844.1420-8-riel@surriel.com
