Introduce a new function to finalize the kernel mappings for the userspace
page-table after all ro/nx protections have been applied to the kernel
mappings.

Also move the call to pti_clone_kernel_text() to that function so that it
will run on 32 bit kernels too.
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Tested-by: NPavel Machek <pavel@ucw.cz>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: linux-mm@kvack.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eduardo Valentin <eduval@amazon.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: aliguori@amazon.com
Cc: daniel.gruss@iaik.tugraz.at
Cc: hughd@google.com
Cc: keescook@google.com
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Waiman Long <llong@redhat.com>
Cc: "David H . Gutteridge" <dhgutteridge@sympatico.ca>
Cc: joro@8bytes.org
Link: https://lkml.kernel.org/r/1531906876-13451-30-git-send-email-joro@8bytes.org

Mapping the kernel text area to user-space makes only sense if it has the
same permissions as in the kernel page-table.  If permissions are different
this will cause a TLB reload when using the kernel page-table, which is as
good as not mapping it at all.

On 64-bit kernels this patch makes no difference, as the whole range cloned
by pti_clone_kernel_text() is mapped RO anyway. On 32 bit there are
writeable mappings in the range, so just keep the permissions as they are.
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Tested-by: NPavel Machek <pavel@ucw.cz>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: linux-mm@kvack.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eduardo Valentin <eduval@amazon.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: aliguori@amazon.com
Cc: daniel.gruss@iaik.tugraz.at
Cc: hughd@google.com
Cc: keescook@google.com
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Waiman Long <llong@redhat.com>
Cc: "David H . Gutteridge" <dhgutteridge@sympatico.ca>
Cc: joro@8bytes.org
Link: https://lkml.kernel.org/r/1531906876-13451-29-git-send-email-joro@8bytes.org

The pti_clone_kernel_text() function references __end_rodata_hpage_align,
which is only present on x86-64.  This makes sense as the end of the rodata
section is not huge-page aligned on 32 bit.

Nevertheless a symbol is required for the function that points at the right
address for both 32 and 64 bit. Introduce __end_rodata_aligned for that
purpose and use it in pti_clone_kernel_text().
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Tested-by: NPavel Machek <pavel@ucw.cz>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: linux-mm@kvack.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eduardo Valentin <eduval@amazon.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: aliguori@amazon.com
Cc: daniel.gruss@iaik.tugraz.at
Cc: hughd@google.com
Cc: keescook@google.com
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Waiman Long <llong@redhat.com>
Cc: "David H . Gutteridge" <dhgutteridge@sympatico.ca>
Cc: joro@8bytes.org
Link: https://lkml.kernel.org/r/1531906876-13451-28-git-send-email-joro@8bytes.org

Cloning on the P4D level would clone the complete kernel address space into
the user-space page-tables for PAE kernels. Cloning on PMD level is fine
for PAE and legacy paging.
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Tested-by: NPavel Machek <pavel@ucw.cz>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: linux-mm@kvack.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eduardo Valentin <eduval@amazon.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: aliguori@amazon.com
Cc: daniel.gruss@iaik.tugraz.at
Cc: hughd@google.com
Cc: keescook@google.com
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Waiman Long <llong@redhat.com>
Cc: "David H . Gutteridge" <dhgutteridge@sympatico.ca>
Cc: joro@8bytes.org
Link: https://lkml.kernel.org/r/1531906876-13451-27-git-send-email-joro@8bytes.org

The addr counter will overflow if the last PMD of the address space is
cloned, resulting in an endless loop.

Check for that and bail out of the loop when it happens.
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Tested-by: NPavel Machek <pavel@ucw.cz>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: linux-mm@kvack.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eduardo Valentin <eduval@amazon.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: aliguori@amazon.com
Cc: daniel.gruss@iaik.tugraz.at
Cc: hughd@google.com
Cc: keescook@google.com
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Waiman Long <llong@redhat.com>
Cc: "David H . Gutteridge" <dhgutteridge@sympatico.ca>
Cc: joro@8bytes.org
Link: https://lkml.kernel.org/r/1531906876-13451-25-git-send-email-joro@8bytes.org

Allocate a kernel and a user page-table root when PTI is enabled. Also
allocate a full page per root for PAE because otherwise the bit to flip in
CR3 to switch between them would be non-constant, which creates a lot of
hassle.  Keep that for a later optimization.
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Tested-by: NPavel Machek <pavel@ucw.cz>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: linux-mm@kvack.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eduardo Valentin <eduval@amazon.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: aliguori@amazon.com
Cc: daniel.gruss@iaik.tugraz.at
Cc: hughd@google.com
Cc: keescook@google.com
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Waiman Long <llong@redhat.com>
Cc: "David H . Gutteridge" <dhgutteridge@sympatico.ca>
Cc: joro@8bytes.org
Link: https://lkml.kernel.org/r/1531906876-13451-18-git-send-email-joro@8bytes.org

The way page-table folding is implemented on 32 bit, these functions are
not only setting, but also PUDs and even PMDs. Give the function a more
generic name to reflect that.
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Tested-by: NPavel Machek <pavel@ucw.cz>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: linux-mm@kvack.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eduardo Valentin <eduval@amazon.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: aliguori@amazon.com
Cc: daniel.gruss@iaik.tugraz.at
Cc: hughd@google.com
Cc: keescook@google.com
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Waiman Long <llong@redhat.com>
Cc: "David H . Gutteridge" <dhgutteridge@sympatico.ca>
Cc: joro@8bytes.org
Link: https://lkml.kernel.org/r/1531906876-13451-16-git-send-email-joro@8bytes.org

pti_set_kernel_image_nonglobal() is only used in pti.c, make it static.
Signed-off-by: NJiang Biao <jiang.biao2@zte.com.cn>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NDave Hansen <dave.hansen@linux.intel.com>
Cc: luto@kernel.org
Cc: hpa@zytor.com
Cc: albcamus@gmail.com
Cc: zhong.weidong@zte.com.cn
Link: https://lkml.kernel.org/r/1531713820-24544-4-git-send-email-jiang.biao2@zte.com.cn

- Remove 'nx_warning' and 'smep_warning', which are just pointless obfuscation.
- Also convert to pr_crit().
Suggested-by: NJoe Perches <joe@perches.com>
Signed-off-by: NDmitry Vyukov <dvyukov@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20180627090715.28076-1-dvyukov@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

KERN_CONT leads to split lines in kernel output
and complicates useful changes to printk like
printing context before each line.

Only acceptable use of continuations is basically
boot-time testing.

Get rid of it.
Signed-off-by: NDmitry Vyukov <dvyukov@google.com>
Reviewed-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20180625123808.227417-1-dvyukov@gmail.com
[ Removed unnecessary parentheses and prettified the printk statement. ]
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Add a new function to "adjust" the current fixed UV memory block size
of 2GB so it can be changed to a different physical boundary.  This is
out of necessity so arch dependent code can accommodate specific BIOS
requirements which can align these new PMEM modules at less than the
default boundaries.

A "set order" type of function was used to insure that the memory block
size will be a power of two value without requiring a validity check.
64GB was chosen as the upper limit for memory block size values to
accommodate upcoming 4PB systems which have 6 more bits of physical
address space (46 becoming 52).
Signed-off-by: NMike Travis <mike.travis@hpe.com>
Reviewed-by: NAndrew Banman <andrew.banman@hpe.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dimitri Sivanich <dimitri.sivanich@hpe.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russ Anderson <russ.anderson@hpe.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dan.j.williams@intel.com
Cc: jgross@suse.com
Cc: kirill.shutemov@linux.intel.com
Cc: mhocko@suse.com
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/lkml/20180524201711.609546602@stormcage.americas.sgi.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

With PHYS_ADDR_MAX there is now a type safe variant for all bits set.
Make use of it.

Patch created using a semantic patch as follows:

// <smpl>
@@
typedef phys_addr_t;
@@
-(phys_addr_t)ULLONG_MAX
+PHYS_ADDR_MAX
// </smpl>

Link: http://lkml.kernel.org/r/20180419214204.19322-1-stefan@agner.chSigned-off-by: NStefan Agner <stefan@agner.ch>
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>	[arm64]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Hussam reports:

    I was poking around and for no real reason, I did cat /dev/mem and
    strings /dev/mem.  Then I saw the following warning in dmesg. I saved it
    and rebooted immediately.

     memremap attempted on mixed range 0x000000000009c000 size: 0x1000
     ------------[ cut here ]------------
     WARNING: CPU: 0 PID: 11810 at kernel/memremap.c:98 memremap+0x104/0x170
     [..]
     Call Trace:
      xlate_dev_mem_ptr+0x25/0x40
      read_mem+0x89/0x1a0
      __vfs_read+0x36/0x170

The memremap() implementation checks for attempts to remap System RAM
with MEMREMAP_WB and instead redirects those mapping attempts to the
linear map.  However, that only works if the physical address range
being remapped is page aligned.  In low memory we have situations like
the following:

    00000000-00000fff : Reserved
    00001000-0009fbff : System RAM
    0009fc00-0009ffff : Reserved

...where System RAM intersects Reserved ranges on a sub-page page
granularity.

Given that devmem_is_allowed() special cases any attempt to map System
RAM in the first 1MB of memory, replace page_is_ram() with the more
precise region_intersects() to trap attempts to map disallowed ranges.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=199999
Link: http://lkml.kernel.org/r/152856436164.18127.2847888121707136898.stgit@dwillia2-desk3.amr.corp.intel.com
Fixes: 92281dee ("arch: introduce memremap()")
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Reported-by: NHussam Al-Tayeb <me@hussam.eu.org>
Tested-by: NHussam Al-Tayeb <me@hussam.eu.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

For pgd page table pages, x86 overloads the page->index field to store a
pointer to the mm_struct.  Rename this to pt_mm so it's visible to other
users.

Link: http://lkml.kernel.org/r/20180518194519.3820-13-willy@infradead.orgSigned-off-by: NMatthew Wilcox <mawilcox@microsoft.com>
Acked-by: NVlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

AMD SME claims one bit from physical address to indicate whether the
page is encrypted or not. To achieve that we clear out the bit from
__PHYSICAL_MASK.

The capability to adjust __PHYSICAL_MASK is required beyond AMD SME.
For instance for upcoming Intel Multi-Key Total Memory Encryption.

Factor it out into a separate feature with own Kconfig handle.

It also helps with overhead of AMD SME. It saves more than 3k in .text
on defconfig + AMD_MEM_ENCRYPT:

	add/remove: 3/2 grow/shrink: 5/110 up/down: 189/-3753 (-3564)

We would need to return to this once we have infrastructure to patch
constants in code. That's good candidate for it.
Signed-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Reviewed-by: NTom Lendacky <thomas.lendacky@amd.com>
Cc: linux-mm@kvack.org
Cc: "H. Peter Anvin" <hpa@zytor.com>
Link: https://lkml.kernel.org/r/20180518113028.79825-1-kirill.shutemov@linux.intel.com

pgtable_l5_enabled is defined using cpu_feature_enabled() but we refer
to it as a variable. This is misleading.

Make pgtable_l5_enabled() a function.

We cannot literally define it as a function due to circular dependencies
between header files. Function-alike macros is close enough.
Signed-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180518103528.59260-4-kirill.shutemov@linux.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Usually pgtable_l5_enabled is defined using cpu_feature_enabled().
cpu_feature_enabled() is not available in early boot code. We use
several different preprocessor tricks to get around it. It's messy.

Unify them all.

If cpu_feature_enabled() is not yet available, USE_EARLY_PGTABLE_L5 can
be defined before all includes. It makes pgtable_l5_enabled rely on
__pgtable_l5_enabled variable instead. This approach fits all early
users.
Signed-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180518103528.59260-3-kirill.shutemov@linux.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

I got a bug report that the following code (roughly) was
causing a SIGSEGV:

	mprotect(ptr, size, PROT_EXEC);
	mprotect(ptr, size, PROT_NONE);
	mprotect(ptr, size, PROT_READ);
	*ptr = 100;

The problem is hit when the mprotect(PROT_EXEC)
is implicitly assigned a protection key to the VMA, and made
that key ACCESS_DENY|WRITE_DENY.  The PROT_NONE mprotect()
failed to remove the protection key, and the PROT_NONE->
PROT_READ left the PTE usable, but the pkey still in place
and left the memory inaccessible.

To fix this, we ensure that we always "override" the pkee
at mprotect() if the VMA does not have execute-only
permissions, but the VMA has the execute-only pkey.

We had a check for PROT_READ/WRITE, but it did not work
for PROT_NONE.  This entirely removes the PROT_* checks,
which ensures that PROT_NONE now works.
Reported-by: NShakeel Butt <shakeelb@google.com>
Signed-off-by: NDave Hansen <dave.hansen@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellermen <mpe@ellerman.id.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Cc: stable@vger.kernel.org
Fixes: 62b5f7d0 ("mm/core, x86/mm/pkeys: Add execute-only protection keys support")
Link: http://lkml.kernel.org/r/20180509171351.084C5A71@viggo.jf.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Converting pr_fmt from a default simple #define to use KBUILD_MODNAME
added some duplicate prefixes.

Remove the duplicate prefixes.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Link: https://lkml.kernel.org/r/e7b709a2b040af7faa81b0aa2c3a125aed628a82.1525964383.git.joe@perches.com

Sometimes it is useful to see which user opcode bytes RIP points to
when a fault happens: be it to rule out RIP corruption, to dump info
early during boot, when doing core dumps is impossible due to not having
a writable filesystem yet.

Sometimes it is useful if debugging an issue and one doesn't have access
to the executable which caused the fault in order to disassemble it.

That last aspect might have some security implications so
show_unhandled_signals could be revisited for that or a new config option
added.
Signed-off-by: NBorislav Petkov <bp@suse.de>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Link: https://lkml.kernel.org/r/20180417161124.5294-7-bp@alien8.de

Call clear_siginfo to ensure every stack allocated siginfo is properly
initialized before being passed to the signal sending functions.

Note: It is not safe to depend on C initializers to initialize struct
siginfo on the stack because C is allowed to skip holes when
initializing a structure.

The initialization of struct siginfo in tracehook_report_syscall_exit
was moved from the helper user_single_step_siginfo into
tracehook_report_syscall_exit itself, to make it clear that the local
variable siginfo gets fully initialized.

In a few cases the scope of struct siginfo has been reduced to make it
clear that siginfo siginfo is not used on other paths in the function
in which it is declared.

Instances of using memset to initialize siginfo have been replaced
with calls clear_siginfo for clarity.
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>

commit 26d35ca6c3776784f8156e1d6f80cc60d9a2a915

RANDSTRUCT derives its hardening benefits from the attacker's lack of
knowledge about the layout of kernel data structures.  Keep the kernel
image non-global in cases where RANDSTRUCT is in use to help keep the
layout a secret.

Fixes: 8c06c774 (x86/pti: Leave kernel text global for !PCID)
Reported-by: NKees Cook <keescook@google.com>
Signed-off-by: NDave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NIngo Molnar <mingo@kernel.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: linux-mm@kvack.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Nadav Amit <namit@vmware.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Link: https://lkml.kernel.org/r/20180420222026.D0B4AAC9@viggo.jf.intel.com

commit abb67605203687c8b7943d760638d0301787f8d9

Kees reported to me that I made too much of the kernel image global.
It was far more than just text:

	I think this is too much set global: _end is after data,
	bss, and brk, and all kinds of other stuff that could
	hold secrets. I think this should match what
	mark_rodata_ro() is doing.

This does exactly that.  We use __end_rodata_hpage_align as our
marker both because it is huge-page-aligned and it does not contain
any sections we expect to hold secrets.

Kees's logic was that r/o data is in the kernel image anyway and,
in the case of traditional distributions, can be freely downloaded
from the web, so there's no reason to hide it.

Fixes: 8c06c774 (x86/pti: Leave kernel text global for !PCID)
Reported-by: NKees Cook <keescook@google.com>
Signed-off-by: NDave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NIngo Molnar <mingo@kernel.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: linux-mm@kvack.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Nadav Amit <namit@vmware.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Link: https://lkml.kernel.org/r/20180420222023.1C8B2B20@viggo.jf.intel.com

commit 231df823c4f04176f607afc4576c989895cff40e

The pageattr.c code attempts to process "faults" when it goes looking
for PTEs to change and finds non-present entries.  It allows these
faults in the linear map which is "expected to have holes", but
WARN()s about them elsewhere, like when called on the kernel image.

However, change_page_attr_clear() is now called on the kernel image in the
process of trying to clear the Global bit.

This trips the warning in __cpa_process_fault() if a non-present PTE is
encountered in the kernel image.  The "holes" in the kernel image result
from free_init_pages()'s use of set_memory_np().  These holes are totally
fine, and result from normal operation, just as they would be in the kernel
linear map.

Just silence the warning when holes in the kernel image are encountered.

Fixes: 39114b7a (x86/pti: Never implicitly clear _PAGE_GLOBAL for kernel image)
Reported-by: NMariusz Ceier <mceier@gmail.com>
Reported-by: NAaro Koskinen <aaro.koskinen@nokia.com>
Signed-off-by: NDave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Tested-by: NAaro Koskinen <aaro.koskinen@nokia.com>
Acked-by: NIngo Molnar <mingo@kernel.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Nadav Amit <namit@vmware.com>
Cc: Kees Cook <keescook@google.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: linux-mm@kvack.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Link: https://lkml.kernel.org/r/20180420222021.1C7D2B3F@viggo.jf.intel.com

commit 16dce603adc9de4237b7bf2ff5c5290f34373e7b

Part of the global bit _setting_ patches also includes clearing the
Global bit when it should not be enabled.  That is done with
set_memory_nonglobal(), which uses change_page_attr_clear() in
pageattr.c under the covers.

The TLB flushing code inside pageattr.c has has checks like
BUG_ON(irqs_disabled()), looking for interrupt disabling that might
cause deadlocks.  But, these also trip in early boot on certain
preempt configurations.  Just copy the existing BUG_ON() sequence from
cpa_flush_range() to the other two sites and check for early boot.

Fixes: 39114b7a (x86/pti: Never implicitly clear _PAGE_GLOBAL for kernel image)
Reported-by: NMariusz Ceier <mceier@gmail.com>
Reported-by: NAaro Koskinen <aaro.koskinen@nokia.com>
Signed-off-by: NDave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Tested-by: NAaro Koskinen <aaro.koskinen@nokia.com>
Acked-by: NIngo Molnar <mingo@kernel.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Nadav Amit <namit@vmware.com>
Cc: Kees Cook <keescook@google.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: linux-mm@kvack.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Link: https://lkml.kernel.org/r/20180420222019.20C4A410@viggo.jf.intel.com

The walk_pte_level() function just uses __va to get the virtual address of
the PTE page, but that breaks when the PTE page is not in the direct
mapping with HIGHPTE=y.

The result is an unhandled kernel paging request at some random address
when accessing the current_kernel or current_user file.

Use the correct API to access PTE pages.

Fixes: fe770bf0 ('x86: clean up the page table dumper and add 32-bit support')
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Cc: jgross@suse.com
Cc: JBeulich@suse.com
Cc: hpa@zytor.com
Cc: aryabinin@virtuozzo.com
Cc: kirill.shutemov@linux.intel.com
Link: https://lkml.kernel.org/r/1523971636-4137-1-git-send-email-joro@8bytes.org

The pmd_set_huge() and pud_set_huge() functions are used from
the generic ioremap() code to establish large mappings where this
is possible.

But the generic ioremap() code does not check whether the
PMD/PUD entries are already populated with a non-leaf entry,
so that any page-table pages these entries point to will be
lost.

Further, on x86-32 with SHARED_KERNEL_PMD=0, this causes a
BUG_ON() in vmalloc_sync_one() when PMD entries are synced
from swapper_pg_dir to the current page-table. This happens
because the PMD entry from swapper_pg_dir was promoted to a
huge-page entry while the current PGD still contains the
non-leaf entry. Because both entries are present and point
to a different page, the BUG_ON() triggers.

This was actually triggered with pti-x32 enabled in a KVM
virtual machine by the graphics driver.

A real and better fix for that would be to improve the
page-table handling in the generic ioremap() code. But that is
out-of-scope for this patch-set and left for later work.
Reported-by: NDavid H. Gutteridge <dhgutteridge@sympatico.ca>
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eduardo Valentin <eduval@amazon.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Waiman Long <llong@redhat.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: aliguori@amazon.com
Cc: daniel.gruss@iaik.tugraz.at
Cc: hughd@google.com
Cc: keescook@google.com
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20180411152437.GC15462@8bytes.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Global pages are bad for hardening because they potentially let an
exploit read the kernel image via a Meltdown-style attack which
makes it easier to find gadgets.

But, global pages are good for performance because they reduce TLB
misses when making user/kernel transitions, especially when PCIDs
are not available, such as on older hardware, or where a hypervisor
has disabled them for some reason.

This patch implements a basic, sane policy: If you have PCIDs, you
only map a minimal amount of kernel text global.  If you do not have
PCIDs, you map all kernel text global.

This policy effectively makes PCIDs something that not only adds
performance but a little bit of hardening as well.

I ran a simple "lseek" microbenchmark[1] to test the benefit on
a modern Atom microserver.  Most of the benefit comes from applying
the series before this patch ("entry only"), but there is still a
signifiant benefit from this patch.

  No Global Lines (baseline  ): 6077741 lseeks/sec
  88 Global Lines (entry only): 7528609 lseeks/sec (+23.9%)
  94 Global Lines (this patch): 8433111 lseeks/sec (+38.8%)

[1.] https://github.com/antonblanchard/will-it-scale/blob/master/tests/lseek1.cSigned-off-by: NDave Hansen <dave.hansen@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kees Cook <keescook@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nadav Amit <namit@vmware.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20180406205518.E3D989EB@viggo.jf.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Summary:

In current kernels, with PTI enabled, no pages are marked Global. This
potentially increases TLB misses.  But, the mechanism by which the Global
bit is set and cleared is rather haphazard.  This patch makes the process
more explicit.  In the end, it leaves us with Global entries in the page
tables for the areas truly shared by userspace and kernel and increases
TLB hit rates.

The place this patch really shines in on systems without PCIDs.  In this
case, we are using an lseek microbenchmark[1] to see how a reasonably
non-trivial syscall behaves.  Higher is better:

  No Global pages (baseline): 6077741 lseeks/sec
  88 Global Pages (this set): 7528609 lseeks/sec (+23.9%)

On a modern Skylake desktop with PCIDs, the benefits are tangible, but not
huge for a kernel compile (lower is better):

  No Global pages (baseline): 186.951 seconds time elapsed  ( +-  0.35% )
  28 Global pages (this set): 185.756 seconds time elapsed  ( +-  0.09% )
                               -1.195 seconds (-0.64%)

I also re-checked everything using the lseek1 test[1]:

  No Global pages (baseline): 15783951 lseeks/sec
  28 Global pages (this set): 16054688 lseeks/sec
			     +270737 lseeks/sec (+1.71%)

The effect is more visible, but still modest.

Details:

The kernel page tables are inherited from head_64.S which rudely marks
them as _PAGE_GLOBAL.  For PTI, we have been relying on the grace of
$DEITY and some insane behavior in pageattr.c to clear _PAGE_GLOBAL.
This patch tries to do better.

First, stop filtering out "unsupported" bits from being cleared in the
pageattr code.  It's fine to filter out *setting* these bits but it
is insane to keep us from clearing them.

Then, *explicitly* go clear _PAGE_GLOBAL from the kernel identity map.
Do not rely on pageattr to do it magically.

After this patch, we can see that "GLB" shows up in each copy of the
page tables, that we have the same number of global entries in each
and that they are the *same* entries.

  /sys/kernel/debug/page_tables/current_kernel:11
  /sys/kernel/debug/page_tables/current_user:11
  /sys/kernel/debug/page_tables/kernel:11

  9caae8ad6a1fb53aca2407ec037f612d  current_kernel.GLB
  9caae8ad6a1fb53aca2407ec037f612d  current_user.GLB
  9caae8ad6a1fb53aca2407ec037f612d  kernel.GLB

A quick visual audit also shows that all the entries make sense.
0xfffffe0000000000 is the cpu_entry_area and 0xffffffff81c00000
is the entry/exit text:

  0xfffffe0000000000-0xfffffe0000002000           8K     ro                 GLB NX pte
  0xfffffe0000002000-0xfffffe0000003000           4K     RW                 GLB NX pte
  0xfffffe0000003000-0xfffffe0000006000          12K     ro                 GLB NX pte
  0xfffffe0000006000-0xfffffe0000007000           4K     ro                 GLB x  pte
  0xfffffe0000007000-0xfffffe000000d000          24K     RW                 GLB NX pte
  0xfffffe000002d000-0xfffffe000002e000           4K     ro                 GLB NX pte
  0xfffffe000002e000-0xfffffe000002f000           4K     RW                 GLB NX pte
  0xfffffe000002f000-0xfffffe0000032000          12K     ro                 GLB NX pte
  0xfffffe0000032000-0xfffffe0000033000           4K     ro                 GLB x  pte
  0xfffffe0000033000-0xfffffe0000039000          24K     RW                 GLB NX pte
  0xffffffff81c00000-0xffffffff81e00000           2M     ro         PSE     GLB x  pmd

[1.] https://github.com/antonblanchard/will-it-scale/blob/master/tests/lseek1.cSigned-off-by: NDave Hansen <dave.hansen@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kees Cook <keescook@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nadav Amit <namit@vmware.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20180406205517.C80FBE05@viggo.jf.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

The entry/exit text and cpu_entry_area are mapped into userspace and
the kernel.  But, they are not _PAGE_GLOBAL.  This creates unnecessary
TLB misses.

Add the _PAGE_GLOBAL flag for these areas.
Signed-off-by: NDave Hansen <dave.hansen@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kees Cook <keescook@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nadav Amit <namit@vmware.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20180406205515.2977EE7D@viggo.jf.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

__ro_after_init data gets stuck in the .rodata section.  That's normally
fine because the kernel itself manages the R/W properties.

But, if we run __change_page_attr() on an area which is __ro_after_init,
the .rodata checks will trigger and force the area to be immediately
read-only, even if it is early-ish in boot.  This caused problems when
trying to clear the _PAGE_GLOBAL bit for these area in the PTI code:
it cleared _PAGE_GLOBAL like I asked, but also took it up on itself
to clear _PAGE_RW.  The kernel then oopses the next time it wrote to
a __ro_after_init data structure.

To fix this, add the kernel_set_to_readonly check, just like we have
for kernel text, just a few lines below in this function.
Signed-off-by: NDave Hansen <dave.hansen@linux.intel.com>
Acked-by: NKees Cook <keescook@chromium.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nadav Amit <namit@vmware.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20180406205514.8D898241@viggo.jf.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

The pageattr code has a mode where it can set or clear PTE bits in
existing PTEs, so the page protections of the *new* PTEs come from
one of two places:

  1. The set/clear masks: cpa->mask_clr / cpa->mask_set
  2. The existing PTE

We filter ->mask_set/clr for supported PTE bits at entry to
__change_page_attr() so we never need to filter them again.

The only other place permissions can come from is an existing PTE
and those already presumably have good bits.  We do not need to filter
them again.
Signed-off-by: NDave Hansen <dave.hansen@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kees Cook <keescook@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nadav Amit <namit@vmware.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20180406205511.BC072352@viggo.jf.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

A PTE is constructed from a physical address and a pgprotval_t.
__PAGE_KERNEL, for instance, is a pgprot_t and must be converted
into a pgprotval_t before it can be used to create a PTE.  This is
done implicitly within functions like pfn_pte() by massage_pgprot().

However, this makes it very challenging to set bits (and keep them
set) if your bit is being filtered out by massage_pgprot().

This moves the bit filtering out of pfn_pte() and friends.  For
users of PAGE_KERNEL*, filtering will be done automatically inside
those macros but for users of __PAGE_KERNEL*, they need to do their
own filtering now.

Note that we also just move pfn_pte/pmd/pud() over to check_pgprot()
instead of massage_pgprot().  This way, we still *look* for
unsupported bits and properly warn about them if we find them.  This
might happen if an unfiltered __PAGE_KERNEL* value was passed in,
for instance.

- printk format warning fix from: Arnd Bergmann <arnd@arndb.de>
- boot crash fix from:            Tom Lendacky <thomas.lendacky@amd.com>
- crash bisected by:              Mike Galbraith <efault@gmx.de>
Signed-off-by: NDave Hansen <dave.hansen@linux.intel.com>
Reported-and-fixed-by: NArnd Bergmann <arnd@arndb.de>
Fixed-by: NTom Lendacky <thomas.lendacky@amd.com>
Bisected-by: NMike Galbraith <efault@gmx.de>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kees Cook <keescook@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nadav Amit <namit@vmware.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20180406205509.77E1D7F6@viggo.jf.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Juergen Gross noticed that commit f7f99100 ("mm: stop zeroing memory
during allocation in vmemmap") broke XEN PV domains when deferred struct
page initialization is enabled.

This is because the xen's PagePinned() flag is getting erased from
struct pages when they are initialized later in boot.

Juergen fixed this problem by disabling deferred pages on xen pv
domains.  It is desirable, however, to have this feature available as it
reduces boot time.  This fix re-enables the feature for pv-dmains, and
fixes the problem the following way:

The fix is to delay setting PagePinned flag until struct pages for all
allocated memory are initialized, i.e.  until after free_all_bootmem().

A new x86_init.hyper op init_after_bootmem() is called to let xen know
that boot allocator is done, and hence struct pages for all the
allocated memory are now initialized.  If deferred page initialization
is enabled, the rest of struct pages are going to be initialized later
in boot once page_alloc_init_late() is called.

xen_after_bootmem() walks page table's pages and marks them pinned.

Link: http://lkml.kernel.org/r/20180226160112.24724-2-pasha.tatashin@oracle.comSigned-off-by: NPavel Tatashin <pasha.tatashin@oracle.com>
Acked-by: NIngo Molnar <mingo@kernel.org>
Reviewed-by: NJuergen Gross <jgross@suse.com>
Tested-by: NJuergen Gross <jgross@suse.com>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Pavel Tatashin <pasha.tatashin@oracle.com>
Cc: Alok Kataria <akataria@vmware.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Mathias Krause <minipli@googlemail.com>
Cc: Jinbum Park <jinb.park7@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Jia Zhang <zhang.jia@linux.alibaba.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Patch series "exec: Pin stack limit during exec".

Attempts to solve problems with the stack limit changing during exec
continue to be frustrated[1][2].  In addition to the specific issues
around the Stack Clash family of flaws, Andy Lutomirski pointed out[3]
other places during exec where the stack limit is used and is assumed to
be unchanging.  Given the many places it gets used and the fact that it
can be manipulated/raced via setrlimit() and prlimit(), I think the only
way to handle this is to move away from the "current" view of the stack
limit and instead attach it to the bprm, and plumb this down into the
functions that need to know the stack limits.  This series implements
the approach.

[1] 04e35f44 ("exec: avoid RLIMIT_STACK races with prlimit()")
[2] 779f4e1c ("Revert "exec: avoid RLIMIT_STACK races with prlimit()"")
[3] to security@kernel.org, "Subject: existing rlimit races?"

This patch (of 3):

Since it is possible that the stack rlimit can change externally during
exec (either via another thread calling setrlimit() or another process
calling prlimit()), provide a way to pass the rlimit down into the
per-architecture mm layout functions so that the rlimit can stay in the
bprm structure instead of sitting in the signal structure until exec is
finalized.

Link: http://lkml.kernel.org/r/1518638796-20819-2-git-send-email-keescook@chromium.orgSigned-off-by: NKees Cook <keescook@chromium.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: Willy Tarreau <w@1wt.eu>
Cc: Hugh Dickins <hughd@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Greg KH <greg@kroah.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ben Hutchings <ben.hutchings@codethink.co.uk>
Cc: Brad Spengler <spender@grsecurity.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The __PAGE_KERNEL_* page permissions are "raw".  They contain bits
that may or may not be supported on the current processor.  They need
to be filtered by a mask (currently __supported_pte_mask) to turn them
into a value that we can actually set in a PTE.

These __PAGE_KERNEL_* values all contain _PAGE_GLOBAL.  But, with PTI,
we want to be able to support _PAGE_GLOBAL (have the bit set in
__supported_pte_mask) but not have it appear in any of these masks by
default.

This patch creates a new mask, __default_kernel_pte_mask, and applies
it when creating all of the PAGE_KERNEL_* masks.  This makes
PAGE_KERNEL_* safe to use anywhere (they only contain supported bits).
It also ensures that PAGE_KERNEL_* contains _PAGE_GLOBAL on PTI=n
kernels but clears _PAGE_GLOBAL when PTI=y.

We also make __default_kernel_pte_mask a non-GPL exported symbol
because there are plenty of driver-available interfaces that take
PAGE_KERNEL_* permissions.
Signed-off-by: NDave Hansen <dave.hansen@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kees Cook <keescook@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nadav Amit <namit@vmware.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20180406205506.030DB6B6@viggo.jf.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

When clearing _PAGE_PRESENT on a huge page, we need to be careful
to also clear _PAGE_PSE, otherwise it might still get confused
for a valid large page table entry.

We do that near the spot where we *set* _PAGE_PSE.  That's fine,
but it's unnecessary.  pgprot_large_2_4k() already did it.

BTW, I also noticed that pgprot_large_2_4k() and
pgprot_4k_2_large() are not symmetric.  pgprot_large_2_4k() clears
_PAGE_PSE (because it is aliased to _PAGE_PAT) but
pgprot_4k_2_large() does not put _PAGE_PSE back.  Bummer.

Also, add some comments and change "promote" to "move".  "Promote"
seems an odd word to move when we are logically moving a bit to a
lower bit position.  Also add an extra line return to make it clear
to which line the comment applies.
Signed-off-by: NDave Hansen <dave.hansen@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kees Cook <keescook@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nadav Amit <namit@vmware.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20180406205504.9B0F44A9@viggo.jf.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

The pageattr code has a pattern repeated where it sets _PAGE_GLOBAL
for present PTEs but clears it for non-present PTEs.  The intention
is to keep _PAGE_GLOBAL from getting confused with _PAGE_PROTNONE
since _PAGE_GLOBAL is for present PTEs and _PAGE_PROTNONE is for
non-present

But, this pattern makes no sense.  Effectively, it says, if you use
the pageattr code, always set _PAGE_GLOBAL when _PAGE_PRESENT.
canon_pgprot() will clear it if unsupported (because it masks the
value with __supported_pte_mask) but we *always* set it. Even if
canon_pgprot() did not filter _PAGE_GLOBAL, it would be OK.
_PAGE_GLOBAL is ignored when CR4.PGE=0 by the hardware.

This unconditional setting of _PAGE_GLOBAL is a problem when we have
PTI and non-PTI and we want some areas to have _PAGE_GLOBAL and some
not.

This updated version of the code says:
1. Clear _PAGE_GLOBAL when !_PAGE_PRESENT
2. Never set _PAGE_GLOBAL implicitly
3. Allow _PAGE_GLOBAL to be in cpa.set_mask
4. Allow _PAGE_GLOBAL to be inherited from previous PTE
Signed-off-by: NDave Hansen <dave.hansen@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kees Cook <keescook@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nadav Amit <namit@vmware.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20180406205502.86E199DA@viggo.jf.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Memory sections are combined into "memory block" chunks.  These chunks
are the units upon which memory can be added and removed.

On x86, the new memory may be added after the end of the boot memory,
therefore, if block size does not align with end of boot memory, memory
hot-plugging/hot-removing can be broken.

Memory sections are combined into "memory block" chunks.  These chunks
are the units upon which memory can be added and removed.

On x86 the new memory may be added after the end of the boot memory,
therefore, if block size does not align with end of boot memory, memory
hotplugging/hotremoving can be broken.

Currently, whenever machine is booted with more than 64G the block size
is unconditionally increased to 2G from the base 128M.  This is done in
order to reduce number of memory device files in sysfs:

	/sys/devices/system/memory/memoryXXX

We must use the largest allowed block size that aligns to the next
address to be able to hotplug the next block of memory.

So, when memory is larger or equal to 64G, we check the end address and
find the largest block size that is still power of two but smaller or
equal to 2G.

Before, the fix:
Run qemu with:
-m 64G,slots=2,maxmem=66G -object memory-backend-ram,id=mem1,size=2G

(qemu) device_add pc-dimm,id=dimm1,memdev=mem1
Block size [0x80000000] unaligned hotplug range: start 0x1040000000,
							size 0x80000000
acpi PNP0C80:00: add_memory failed
acpi PNP0C80:00: acpi_memory_enable_device() error
acpi PNP0C80:00: Enumeration failure

With the fix memory is added successfully as the block size is set to
1G, and therefore aligns with start address 0x1040000000.

[pasha.tatashin@oracle.com: v4]
  Link: http://lkml.kernel.org/r/20180215165920.8570-3-pasha.tatashin@oracle.com
Link: http://lkml.kernel.org/r/20180213193159.14606-3-pasha.tatashin@oracle.comSigned-off-by: NPavel Tatashin <pasha.tatashin@oracle.com>
Reviewed-by: NIngo Molnar <mingo@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Steven Sistare <steven.sistare@oracle.com>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Bharata B Rao <bharata@linux.vnet.ibm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Baoquan He <bhe@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

node_memmap_size_bytes() has been unused since the v3.9 kernel, so remove it.
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Fixes: f03574f2 ("x86-32, mm: Rip out x86_32 NUMA remapping code")
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1803262325540.256524@chino.kir.corp.google.comSigned-off-by: NIngo Molnar <mingo@kernel.org>