There's a mixture of signed 32-bit and unsigned 32-bit and 64-bit data
types used for keeping track of how many pages have been mapped.
This leads to hangs during boot when mapping large numbers of pages
(multiple terabytes, as reported by Waiman) because those values are
interpreted as being negative.
commit 742563777e ("x86/mm/pat: Avoid truncation when converting
cpa->numpages to address") fixed one of those bugs, but there is
another lurking in __change_page_attr_set_clr().
Additionally, the return value type for the populate_*() functions can
return negative values when a large number of pages have been mapped,
triggering the error paths even though no error occurred.
Consistently use 64-bit types on 64-bit platforms when counting pages.
Even in the signed case this gives us room for regions 8PiB
(pebibytes) in size whilst still allowing the usual negative value
error checking idiom.
Reported-by: Waiman Long <waiman.long@hpe.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
CC: Theodore Ts'o <tytso@mit.edu>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Scott J Norton <scott.norton@hpe.com>
Cc: Douglas Hatch <doug.hatch@hpe.com>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Pull x86 boot updates from Ingo Molnar:
"The main changes:
- add initial commits to randomize kernel memory section virtual
addresses, enabled via a new kernel option: RANDOMIZE_MEMORY
(Thomas Garnier, Kees Cook, Baoquan He, Yinghai Lu)
- enhance KASLR (RANDOMIZE_BASE) physical memory randomization (Kees
Cook)
- EBDA/BIOS region boot quirk cleanups (Andy Lutomirski, Ingo Molnar)
- misc cleanups/fixes"
* 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/boot: Simplify EBDA-vs-BIOS reservation logic
x86/boot: Clarify what x86_legacy_features.reserve_bios_regions does
x86/boot: Reorganize and clean up the BIOS area reservation code
x86/mm: Do not reference phys addr beyond kernel
x86/mm: Add memory hotplug support for KASLR memory randomization
x86/mm: Enable KASLR for vmalloc memory regions
x86/mm: Enable KASLR for physical mapping memory regions
x86/mm: Implement ASLR for kernel memory regions
x86/mm: Separate variable for trampoline PGD
x86/mm: Add PUD VA support for physical mapping
x86/mm: Update physical mapping variable names
x86/mm: Refactor KASLR entropy functions
x86/KASLR: Fix boot crash with certain memory configurations
x86/boot/64: Add forgotten end of function marker
x86/KASLR: Allow randomization below the load address
x86/KASLR: Extend kernel image physical address randomization to addresses larger than 4G
x86/KASLR: Randomize virtual address separately
x86/KASLR: Clarify identity map interface
x86/boot: Refuse to build with data relocations
x86/KASLR, x86/power: Remove x86 hibernation restrictions
In commit:
21cbc2822aa1 ("x86/mm/cpa: Unbreak populate_pgd(): stop trying to deallocate failed PUDs")
I intended to add this comment, but I failed at using git.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/242baf8612394f4e31216f96d13c4d2e9b90d1b7.1469293159.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Valdis Kletnieks bisected a boot failure back to this recent commit:
360cb4d155 ("x86/mm/cpa: In populate_pgd(), don't set the PGD entry until it's populated")
I broke the case where a PUD table got allocated -- populate_pud()
would wander off a pgd_none entry and get lost. I'm not sure how
this survived my testing.
Fix the original issue in a much simpler way. The problem
was that, if we allocated a PUD table, failed to populate it, and
freed it, another CPU could potentially keep using the PGD entry we
installed (either by copying it via vmalloc_fault or by speculatively
caching it). There's a straightforward fix: simply leave the
top-level entry in place if this happens. This can't waste any
significant amount of memory -- there are at most 256 entries like
this systemwide and, as a practical matter, if we hit this failure
path repeatedly, we're likely to reuse the same page anyway.
For context, this is a reversion with this hunk added in:
if (ret < 0) {
+ /*
+ * Leave the PUD page in place in case some other CPU or thread
+ * already found it, but remove any useless entries we just
+ * added to it.
+ */
- unmap_pgd_range(cpa->pgd, addr,
+ unmap_pud_range(pgd_entry, addr,
addr + (cpa->numpages << PAGE_SHIFT));
return ret;
}
This effectively open-codes what the now-deleted unmap_pgd_range()
function used to do except that unmap_pgd_range() used to try to
free the page as well.
Reported-by: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Mike Krinkin <krinkin.m.u@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Toshi Kani <toshi.kani@hp.com>
Link: http://lkml.kernel.org/r/21cbc2822aa18aa812c0215f4231dbf5f65afa7f.1469249789.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
kernel_unmap_pages_in_pgd() is dangerous: if a PGD entry in
init_mm.pgd were to be cleared, callers would need to ensure that
the pgd entry hadn't been propagated to any other pgd.
Its only caller was efi_cleanup_page_tables(), and that, in turn,
was unused, so just delete both functions. This leaves a couple of
other helpers unused, so delete them, too.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Acked-by: Borislav Petkov <bp@suse.de>
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>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/77ff20fdde3b75cd393be5559ad8218870520248.1468527351.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This avoids pointless races in which another CPU or task might see a
partially populated global PGD entry. These races should normally
be harmless, but, if another CPU propagates the entry via
vmalloc_fault() and then populate_pgd() fails (due to memory allocation
failure, for example), this prevents a use-after-free of the PGD
entry.
Signed-off-by: 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/bf99df27eac6835f687005364bd1fbd89130946c.1468527351.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The page table manipulation code seems to have grown a couple of
sites that are looking for empty PTEs. Just in case one of these
entries got a stray bit set, use pte_none() instead of checking
for a zero pte_val().
The use pte_same() makes me a bit nervous. If we were doing a
pte_same() check against two cleared entries and one of them had
a stray bit set, it might fail the pte_same() check. But, I
don't think we ever _do_ pte_same() for cleared entries. It is
almost entirely used for checking for races in fault-in paths.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave@sr71.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: dave.hansen@intel.com
Cc: linux-mm@kvack.org
Cc: mhocko@suse.com
Link: http://lkml.kernel.org/r/20160708001915.813703D9@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The new physical address randomized KASLR implementation can cause the
kernel to be aligned close to the end of physical memory. In this case,
_brk_end aligned to PMD will go beyond what is expected safe and hit
the assert in __phys_addr_symbol():
VIRTUAL_BUG_ON(y >= KERNEL_IMAGE_SIZE);
Instead, perform an inclusive range check to avoid incorrectly triggering
the assert:
kernel BUG at arch/x86/mm/physaddr.c:38!
invalid opcode: 0000 [#1] SMP
...
RIP: 0010:[<ffffffffbe055721>] __phys_addr_symbol+0x41/0x50
...
Call Trace:
[<ffffffffbe052eb9>] cpa_process_alias+0xa9/0x210
[<ffffffffbe109011>] ? do_raw_spin_unlock+0xc1/0x100
[<ffffffffbe051eef>] __change_page_attr_set_clr+0x8cf/0xbd0
[<ffffffffbe201a4d>] ? vm_unmap_aliases+0x7d/0x210
[<ffffffffbe05237c>] change_page_attr_set_clr+0x18c/0x4e0
[<ffffffffbe0534ec>] set_memory_4k+0x2c/0x40
[<ffffffffbefb08b3>] check_bugs+0x28/0x2a
[<ffffffffbefa4f52>] start_kernel+0x49d/0x4b9
[<ffffffffbefa4120>] ? early_idt_handler_array+0x120/0x120
[<ffffffffbefa4423>] x86_64_start_reservations+0x29/0x2b
[<ffffffffbefa4568>] x86_64_start_kernel+0x143/0x152
Signed-off-by: Thomas Garnier <thgarnie@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sai Praneeth <sai.praneeth.prakhya@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Toshi Kani <toshi.kani@hpe.com>
Link: http://lkml.kernel.org/r/20160615190545.GA26071@www.outflux.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull x86 asm updates from Ingo Molnar:
"The main changes in this cycle were:
- MSR access API fixes and enhancements (Andy Lutomirski)
- early exception handling improvements (Andy Lutomirski)
- user-space FS/GS prctl usage fixes and improvements (Andy
Lutomirski)
- Remove the cpu_has_*() APIs and replace them with equivalents
(Borislav Petkov)
- task switch micro-optimization (Brian Gerst)
- 32-bit entry code simplification (Denys Vlasenko)
- enhance PAT handling in enumated CPUs (Toshi Kani)
... and lots of other cleanups/fixlets"
* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (70 commits)
x86/arch_prctl/64: Restore accidentally removed put_cpu() in ARCH_SET_GS
x86/entry/32: Remove asmlinkage_protect()
x86/entry/32: Remove GET_THREAD_INFO() from entry code
x86/entry, sched/x86: Don't save/restore EFLAGS on task switch
x86/asm/entry/32: Simplify pushes of zeroed pt_regs->REGs
selftests/x86/ldt_gdt: Test set_thread_area() deletion of an active segment
x86/tls: Synchronize segment registers in set_thread_area()
x86/asm/64: Rename thread_struct's fs and gs to fsbase and gsbase
x86/arch_prctl/64: Remove FSBASE/GSBASE < 4G optimization
x86/segments/64: When load_gs_index fails, clear the base
x86/segments/64: When loadsegment(fs, ...) fails, clear the base
x86/asm: Make asm/alternative.h safe from assembly
x86/asm: Stop depending on ptrace.h in alternative.h
x86/entry: Rename is_{ia32,x32}_task() to in_{ia32,x32}_syscall()
x86/asm: Make sure verify_cpu() has a good stack
x86/extable: Add a comment about early exception handlers
x86/msr: Set the return value to zero when native_rdmsr_safe() fails
x86/paravirt: Make "unsafe" MSR accesses unsafe even if PARAVIRT=y
x86/paravirt: Add paravirt_{read,write}_msr()
x86/msr: Carry on after a non-"safe" MSR access fails
...
It's not at all obvious that populate_pgd() and friends are only
executed when mapping EFI virtual memory regions or that no other
pageattr callers pass a ->pgd value.
Reported-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1461614832-17633-4-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull EFI updates from Ingo Molnar:
"The main changes are:
- Use separate EFI page tables when executing EFI firmware code.
This isolates the EFI context from the rest of the kernel, which
has security and general robustness advantages. (Matt Fleming)
- Run regular UEFI firmware with interrupts enabled. This is already
the status quo under other OSs. (Ard Biesheuvel)
- Various x86 EFI enhancements, such as the use of non-executable
attributes for EFI memory mappings. (Sai Praneeth Prakhya)
- Various arm64 UEFI enhancements. (Ard Biesheuvel)
- ... various fixes and cleanups.
The separate EFI page tables feature got delayed twice already,
because it's an intrusive change and we didn't feel confident about
it - third time's the charm we hope!"
* 'efi-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (37 commits)
x86/mm/pat: Fix boot crash when 1GB pages are not supported by the CPU
x86/efi: Only map kernel text for EFI mixed mode
x86/efi: Map EFI_MEMORY_{XP,RO} memory region bits to EFI page tables
x86/mm/pat: Don't implicitly allow _PAGE_RW in kernel_map_pages_in_pgd()
efi/arm*: Perform hardware compatibility check
efi/arm64: Check for h/w support before booting a >4 KB granular kernel
efi/arm: Check for LPAE support before booting a LPAE kernel
efi/arm-init: Use read-only early mappings
efi/efistub: Prevent __init annotations from being used
arm64/vmlinux.lds.S: Handle .init.rodata.xxx and .init.bss sections
efi/arm64: Drop __init annotation from handle_kernel_image()
x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page table mappings
efi/runtime-wrappers: Run UEFI Runtime Services with interrupts enabled
efi: Reformat GUID tables to follow the format in UEFI spec
efi: Add Persistent Memory type name
efi: Add NV memory attribute
x86/efi: Show actual ending addresses in efi_print_memmap
x86/efi/bgrt: Don't ignore the BGRT if the 'valid' bit is 0
efivars: Use to_efivar_entry
efi: Runtime-wrapper: Get rid of the rtc_lock spinlock
...
Merge first patch-bomb from Andrew Morton:
- some misc things
- ofs2 updates
- about half of MM
- checkpatch updates
- autofs4 update
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (120 commits)
autofs4: fix string.h include in auto_dev-ioctl.h
autofs4: use pr_xxx() macros directly for logging
autofs4: change log print macros to not insert newline
autofs4: make autofs log prints consistent
autofs4: fix some white space errors
autofs4: fix invalid ioctl return in autofs4_root_ioctl_unlocked()
autofs4: fix coding style line length in autofs4_wait()
autofs4: fix coding style problem in autofs4_get_set_timeout()
autofs4: coding style fixes
autofs: show pipe inode in mount options
kallsyms: add support for relative offsets in kallsyms address table
kallsyms: don't overload absolute symbol type for percpu symbols
x86: kallsyms: disable absolute percpu symbols on !SMP
checkpatch: fix another left brace warning
checkpatch: improve UNSPECIFIED_INT test for bare signed/unsigned uses
checkpatch: warn on bare unsigned or signed declarations without int
checkpatch: exclude asm volatile from complex macro check
mm: memcontrol: drop unnecessary lru locking from mem_cgroup_migrate()
mm: migrate: consolidate mem_cgroup_migrate() calls
mm/compaction: speed up pageblock_pfn_to_page() when zone is contiguous
...
Scott reports that with the new separate EFI page tables he's seeing
the following error on boot, caused by setting reserved bits in the
page table structures (fault code is PF_RSVD | PF_PROT),
swapper/0: Corrupted page table at address 17b102020
PGD 17b0e5063 PUD 1400000e3
Bad pagetable: 0009 [#1] SMP
On first inspection the PUD is using a 1GB page size (_PAGE_PSE) and
looks fine but that's only true if support for 1GB PUD pages
("pdpe1gb") is present in the CPU.
Scott's Intel Celeron N2820 does not have that feature and so the
_PAGE_PSE bit is reserved. Fix this issue by making the 1GB mapping
code in conditional on "cpu_has_gbpages".
This issue didn't come up in the past because the required mapping for
the faulting address (0x17b102020) will already have been setup by the
kernel in early boot before we got to efi_map_regions(), but we no
longer use the standard kernel page tables during EFI calls.
Reported-by: Scott Ashcroft <scott.ashcroft@talk21.com>
Tested-by: Scott Ashcroft <scott.ashcroft@talk21.com>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Acked-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Raphael Hertzog <hertzog@debian.org>
Cc: Roger Shimizu <rogershimizu@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1457951581-27353-2-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We can use debug_pagealloc_enabled() to check if we can map the identity
mapping with 2MB pages. We can also add the state into the dump_stack
output.
The patch does not touch the code for the 1GB pages, which ignored
CONFIG_DEBUG_PAGEALLOC. Do we need to fence this as well?
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Laura Abbott <labbott@fedoraproject.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull x86 mm updates from Ingo Molnar:
"The main changes in this cycle were:
- Enable full ASLR randomization for 32-bit programs (Hector
Marco-Gisbert)
- Add initial minimal INVPCI support, to flush global mappings (Andy
Lutomirski)
- Add KASAN enhancements (Andrey Ryabinin)
- Fix mmiotrace for huge pages (Karol Herbst)
- ... misc cleanups and small enhancements"
* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mm/32: Enable full randomization on i386 and X86_32
x86/mm/kmmio: Fix mmiotrace for hugepages
x86/mm: Avoid premature success when changing page attributes
x86/mm/ptdump: Remove paravirt_enabled()
x86/mm: Fix INVPCID asm constraint
x86/dmi: Switch dmi_remap() from ioremap() [uncached] to ioremap_cache()
x86/mm: If INVPCID is available, use it to flush global mappings
x86/mm: Add a 'noinvpcid' boot option to turn off INVPCID
x86/mm: Add INVPCID helpers
x86/kasan: Write protect kasan zero shadow
x86/kasan: Clear kasan_zero_page after TLB flush
x86/mm/numa: Check for failures in numa_clear_kernel_node_hotplug()
x86/mm/numa: Clean up numa_clear_kernel_node_hotplug()
x86/mm: Make kmap_prot into a #define
x86/mm/32: Set NX in __supported_pte_mask before enabling paging
x86/mm: Streamline and restore probe_memory_block_size()
Pull read-only kernel memory updates from Ingo Molnar:
"This tree adds two (security related) enhancements to the kernel's
handling of read-only kernel memory:
- extend read-only kernel memory to a new class of formerly writable
kernel data: 'post-init read-only memory' via the __ro_after_init
attribute, and mark the ARM and x86 vDSO as such read-only memory.
This kind of attribute can be used for data that requires a once
per bootup initialization sequence, but is otherwise never modified
after that point.
This feature was based on the work by PaX Team and Brad Spengler.
(by Kees Cook, the ARM vDSO bits by David Brown.)
- make CONFIG_DEBUG_RODATA always enabled on x86 and remove the
Kconfig option. This simplifies the kernel and also signals that
read-only memory is the default model and a first-class citizen.
(Kees Cook)"
* 'mm-readonly-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
ARM/vdso: Mark the vDSO code read-only after init
x86/vdso: Mark the vDSO code read-only after init
lkdtm: Verify that '__ro_after_init' works correctly
arch: Introduce post-init read-only memory
x86/mm: Always enable CONFIG_DEBUG_RODATA and remove the Kconfig option
mm/init: Add 'rodata=off' boot cmdline parameter to disable read-only kernel mappings
asm-generic: Consolidate mark_rodata_ro()
"d1cd12108346: x86, pageattr: Prevent overflow in slow_virt_to_phys() for
X86_PAE" was unintentionally removed by the recent "34437e67a672: x86/mm: Fix
slow_virt_to_phys() to handle large PAT bit".
And, the variable 'phys_addr' was defined as "unsigned long" by mistake -- it should
be "phys_addr_t".
As a result, Hyper-V network driver in 32-PAE Linux guest can't work again.
Fixes: commit 34437e67a6: "x86/mm: Fix slow_virt_to_phys() to handle large PAT bit"
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Reviewed-by: Toshi Kani <toshi.kani@hpe.com>
Cc: olaf@aepfle.de
Cc: gregkh@linuxfoundation.org
Cc: jasowang@redhat.com
Cc: driverdev-devel@linuxdriverproject.org
Cc: linux-mm@kvack.org
Cc: apw@canonical.com
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Link: http://lkml.kernel.org/r/1456394292-9030-1-git-send-email-decui@microsoft.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
set_memory_nx() (and set_memory_x()) currently differ in behavior from
all other set_memory_*() functions when encountering a virtual address
space hole within the kernel address range: They stop processing at the
hole, but nevertheless report success (making the caller believe the
operation was carried out on the entire range). While observed to be a
problem - triggering the CONFIG_DEBUG_WX warning - only with out of
tree code, I suspect (but didn't check) that on x86-64 the
CONFIG_DEBUG_PAGEALLOC logic in free_init_pages() would, when called
from free_initmem(), have the same effect on the set_memory_nx() called
from mark_rodata_ro().
This unexpected behavior is a result of change_page_attr_set_clr()
special casing changes to only the NX bit, in that it passes "false" as
the "checkalias" argument to __change_page_attr_set_clr(). Since this
flag becomes the "primary" argument of both __change_page_attr() and
__cpa_process_fault(), the latter would so far return success without
adjusting cpa->numpages. Success to the higher level callers, however,
means that whatever cpa->numpages currently holds is the count of
successfully processed pages. The cases when __change_page_attr() calls
__cpa_process_fault(), otoh, don't generally mean the entire range got
processed (as can be seen from one of the two success return paths in
__cpa_process_fault() already adjusting ->numpages).
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/56BB0AD402000078000D05BF@prv-mh.provo.novell.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This removes the CONFIG_DEBUG_RODATA option and makes it always enabled.
This simplifies the code and also makes it clearer that read-only mapped
memory is just as fundamental a security feature in kernel-space as it is
in user-space.
Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Brown <david.brown@linaro.org>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Emese Revfy <re.emese@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathias Krause <minipli@googlemail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: PaX Team <pageexec@freemail.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kernel-hardening@lists.openwall.com
Cc: linux-arch <linux-arch@vger.kernel.org>
Link: http://lkml.kernel.org/r/1455748879-21872-4-git-send-email-keescook@chromium.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
As part of the preparation for the EFI_MEMORY_RO flag added in the UEFI
2.5 specification, we need the ability to map pages in kernel page
tables without _PAGE_RW being set.
Modify kernel_map_pages_in_pgd() to require its callers to pass _PAGE_RW
if the pages need to be mapped read/write. Otherwise, we'll map the
pages as read-only.
Signed-off-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.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: Hugh Dickins <hughd@google.com>
Cc: Lee, Chun-Yi <jlee@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Shankar <ravi.v.shankar@intel.com>
Cc: Ricardo Neri <ricardo.neri@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1455712566-16727-12-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Since EFI page tables can be treated as kernel page tables they should
be global. All the other page mapping functions in pageattr.c set the
_PAGE_GLOBAL bit and we want to avoid inconsistencies when we map a page
in the EFI code paths, for example when that page is split in
__split_large_page(), etc. It also makes it easier to validate that the
EFI region mappings have the correct attributes because there are fewer
differences compared with regular kernel mappings.
Signed-off-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.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: Hugh Dickins <hughd@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Shankar <ravi.v.shankar@intel.com>
Cc: Ricardo Neri <ricardo.neri@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1455712566-16727-4-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
There are a couple of nasty truncation bugs lurking in the pageattr
code that can be triggered when mapping EFI regions, e.g. when we pass
a cpa->pgd pointer. Because cpa->numpages is a 32-bit value, shifting
left by PAGE_SHIFT will truncate the resultant address to 32-bits.
Viorel-Cătălin managed to trigger this bug on his Dell machine that
provides a ~5GB EFI region which requires 1236992 pages to be mapped.
When calling populate_pud() the end of the region gets calculated
incorrectly in the following buggy expression,
end = start + (cpa->numpages << PAGE_SHIFT);
And only 188416 pages are mapped. Next, populate_pud() gets invoked
for a second time because of the loop in __change_page_attr_set_clr(),
only this time no pages get mapped because shifting the remaining
number of pages (1048576) by PAGE_SHIFT is zero. At which point the
loop in __change_page_attr_set_clr() spins forever because we fail to
map progress.
Hitting this bug depends very much on the virtual address we pick to
map the large region at and how many pages we map on the initial run
through the loop. This explains why this issue was only recently hit
with the introduction of commit
a5caa209ba ("x86/efi: Fix boot crash by mapping EFI memmap
entries bottom-up at runtime, instead of top-down")
It's interesting to note that safe uses of cpa->numpages do exist in
the pageattr code. If instead of shifting ->numpages we multiply by
PAGE_SIZE, no truncation occurs because PAGE_SIZE is a UL value, and
so the result is unsigned long.
To avoid surprises when users try to convert very large cpa->numpages
values to addresses, change the data type from 'int' to 'unsigned
long', thereby making it suitable for shifting by PAGE_SHIFT without
any type casting.
The alternative would be to make liberal use of casting, but that is
far more likely to cause problems in the future when someone adds more
code and fails to cast properly; this bug was difficult enough to
track down in the first place.
Reported-and-tested-by: Viorel-Cătălin Răpițeanu <rapiteanu.catalin@gmail.com>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=110131
Link: http://lkml.kernel.org/r/1454067370-10374-1-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
In CONFIG_PAGEALLOC_DEBUG=y builds, we disable 2M pages.
Unfortunatly when we split up mappings during boot,
split_page_count() doesn't take this into account, and
starts decrementing an empty direct_pages_count[] level.
This results in /proc/meminfo showing crazy things like:
DirectMap2M: 18446744073709543424 kB
Signed-off-by: Dave Jones <davej@codemonkey.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Toshi Kani <toshi.kani@hp.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Whilst inspecting the asm for clflush_cache_range() and some perf profiles
that required extensive flushing of single cachelines (from part of the
intel-gpu-tools GPU benchmarks), we noticed that gcc was reloading
boot_cpu_data.x86_clflush_size on every iteration of the loop. We can
manually hoist that read which perf regarded as taking ~25% of the
function time for a single cacheline flush.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Acked-by: "H. Peter Anvin" <hpa@zytor.com>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Sai Praneeth <sai.praneeth.prakhya@intel.com>
Link: http://lkml.kernel.org/r/1452246933-10890-1-git-send-email-chris@chris-wilson.co.uk
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The x86 pageattr code is confused about the data that is stored
in cpa->pfn, sometimes it's treated as a page frame number,
sometimes it's treated as an unshifted physical address, and in
one place it's treated as a pte.
The result of this is that the mapping functions do not map the
intended physical address.
This isn't a problem in practice because most of the addresses
we're mapping in the EFI code paths are already mapped in
'trampoline_pgd' and so the pageattr mapping functions don't
actually do anything in this case. But when we move to using a
separate page table for the EFI runtime this will be an issue.
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Reviewed-by: Borislav Petkov <bp@suse.de>
Acked-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@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: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1448658575-17029-3-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull x86 mm changes from Ingo Molnar:
"The main changes are: continued PAT work by Toshi Kani, plus a new
boot time warning about insecure RWX kernel mappings, by Stephen
Smalley.
The new CONFIG_DEBUG_WX=y warning is marked default-y if
CONFIG_DEBUG_RODATA=y is already eanbled, as a special exception, as
these bugs are hard to notice and this check already found several
live bugs"
* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mm: Warn on W^X mappings
x86/mm: Fix no-change case in try_preserve_large_page()
x86/mm: Fix __split_large_page() to handle large PAT bit
x86/mm: Fix try_preserve_large_page() to handle large PAT bit
x86/mm: Fix gup_huge_p?d() to handle large PAT bit
x86/mm: Fix slow_virt_to_phys() to handle large PAT bit
x86/mm: Fix page table dump to show PAT bit
x86/asm: Add pud_pgprot() and pmd_pgprot()
x86/asm: Fix pud/pmd interfaces to handle large PAT bit
x86/asm: Add pud/pmd mask interfaces to handle large PAT bit
x86/asm: Move PUD_PAGE macros to page_types.h
x86/vdso32: Define PGTABLE_LEVELS to 32bit VDSO
__pa() in the x86 pageattr code. Since these virtual addreses are
not part of the direct mapping or kernel text mapping, passing them
to __pa() will trigger a BUG_ON() when CONFIG_DEBUG_VIRTUAL is
enabled - Sai Praneeth Prakhya
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Merge tag 'efi-next' of git://git.kernel.org/pub/scm/linux/kernel/git/mfleming/efi into core/efi
Pull EFI fix from Matt Fleming:
- Fix a kernel panic by not passing EFI virtual mapping addresses to
__pa() in the x86 pageattr code. Since these virtual addreses are
not part of the direct mapping or kernel text mapping, passing them
to __pa() will trigger a BUG_ON() when CONFIG_DEBUG_VIRTUAL is
enabled. (Sai Praneeth Prakhya)
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When CONFIG_DEBUG_VIRTUAL is enabled, all accesses to __pa(address) are
monitored to see whether address falls in direct mapping or kernel text
mapping (see Documentation/x86/x86_64/mm.txt for details), if it does
not, the kernel panics. During 1:1 mapping of EFI runtime services we access
virtual addresses which are == physical addresses, thus the 1:1 mapping
and these addresses do not fall in either of the above two regions and
hence when passed as arguments to __pa() kernel panics as reported by
Dave Hansen here https://lkml.kernel.org/r/5462999A.7090706@intel.com.
So, before calling __pa() virtual addresses should be validated which
results in skipping call to split_page_count() and that should be fine
because it is used to keep track of everything *but* 1:1 mappings.
Signed-off-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Reported-by: Dave Hansen <dave.hansen@intel.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: Ricardo Neri <ricardo.neri@intel.com>
Cc: Glenn P Williamson <glenn.p.williamson@intel.com>
Cc: Ravi Shankar <ravi.v.shankar@intel.com>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
try_preserve_large_page() checks if new_prot is the same as
old_prot. If so, it simply sets do_split to 0, and returns
with no-operation. However, old_prot is set as a 4KB pgprot
value while new_prot is a large page pgprot value.
Now that old_prot is initially set from p?d_pgprot() as a
large page pgprot value, fix it by not overwriting old_prot
with a 4KB pgprot value.
Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Juergen Gross <jgross@suse.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Konrad Wilk <konrad.wilk@oracle.com>
Cc: Robert Elliot <elliott@hpe.com>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/1442514264-12475-12-git-send-email-toshi.kani@hpe.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
__split_large_page() is called from __change_page_attr() to change
the mapping attribute by splitting a given large page into smaller
pages. This function uses pte_pfn() and pte_pgprot() for PUD/PMD,
which do not handle the large PAT bit properly.
Fix __split_large_page() by using the corresponding pud/pmd pfn/
pgprot interfaces.
Also remove '#ifdef CONFIG_X86_64', which is not necessary.
Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Juergen Gross <jgross@suse.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Konrad Wilk <konrad.wilk@oracle.com>
Cc: Robert Elliot <elliott@hpe.com>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/1442514264-12475-11-git-send-email-toshi.kani@hpe.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
try_preserve_large_page() is called from __change_page_attr() to
change the mapping attribute of a given large page. This function
uses pte_pfn() and pte_pgprot() for PUD/PMD, which do not handle
the large PAT bit properly.
Fix try_preserve_large_page() by using the corresponding pud/pmd
prot/pfn interfaces.
Also remove '#ifdef CONFIG_X86_64', which is not necessary.
Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Juergen Gross <jgross@suse.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Konrad Wilk <konrad.wilk@oracle.com>
Cc: Robert Elliot <elliott@hpe.com>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/1442514264-12475-10-git-send-email-toshi.kani@hpe.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
slow_virt_to_phys() calls lookup_address() to obtain *pte and
its level. It then calls pte_pfn() to obtain a physical address
for any level. However, this physical address is not correct
when the large PAT bit is set because pte_pfn() does not mask
the large PAT bit properly for PUD/PMD.
Fix slow_virt_to_phys() to use pud_pfn() and pmd_pfn() for 1GB
and 2MB mapping levels.
Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Juergen Gross <jgross@suse.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Konrad Wilk <konrad.wilk@oracle.com>
Cc: Robert Elliot <elliott@hpe.com>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/1442514264-12475-8-git-send-email-toshi.kani@hpe.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The file pageattr.c is obj-y and it includes pageattr-test.c
based on CPA_DEBUG (a bool), meaning that no code here is
currently being built as a module by anyone.
Lets remove the couple traces of modularity so that when reading
the code there is no doubt it is builtin-only.
Since module_init translates to device_initcall in the
non-modular case, the init ordering remains unchanged with this
commit.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1440459295-21814-3-git-send-email-paul.gortmaker@windriver.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Now that reserve_ram_pages_type() accepts the WT type, add
set_memory_wt(), set_memory_array_wt() and set_pages_array_wt()
in order to be able to set memory to Write-Through page cache
mode.
Also, extend ioremap_change_attr() to accept the WT type.
Signed-off-by: Toshi Kani <toshi.kani@hp.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Elliott@hp.com
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: arnd@arndb.de
Cc: hch@lst.de
Cc: hmh@hmh.eng.br
Cc: jgross@suse.com
Cc: konrad.wilk@oracle.com
Cc: linux-mm <linux-mm@kvack.org>
Cc: linux-nvdimm@lists.01.org
Cc: stefan.bader@canonical.com
Cc: yigal@plexistor.com
Link: http://lkml.kernel.org/r/1433436928-31903-13-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Now that we emulate a PAT table when PAT is disabled, there's no
need for those checks anymore as the PAT abstraction will handle
those cases too.
Based on a conglomerate patch from Toshi Kani.
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Toshi Kani <toshi.kani@hp.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Elliott@hp.com
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: arnd@arndb.de
Cc: hch@lst.de
Cc: hmh@hmh.eng.br
Cc: jgross@suse.com
Cc: konrad.wilk@oracle.com
Cc: linux-mm <linux-mm@kvack.org>
Cc: linux-nvdimm@lists.01.org
Cc: stefan.bader@canonical.com
Cc: yigal@plexistor.com
Link: http://lkml.kernel.org/r/1433436928-31903-4-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Nothing in <asm/io.h> uses anything from <linux/vmalloc.h>, so
remove it from there and fix up the resulting build problems
triggered on x86 {64|32}-bit {def|allmod|allno}configs.
The breakages were triggering in places where x86 builds relied
on vmalloc() facilities but did not include <linux/vmalloc.h>
explicitly and relied on the implicit inclusion via <asm/io.h>.
Also add:
- <linux/init.h> to <linux/io.h>
- <asm/pgtable_types> to <asm/io.h>
... which were two other implicit header file dependencies.
Suggested-by: David Miller <davem@davemloft.net>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
[ Tidied up the changelog. ]
Acked-by: David Miller <davem@davemloft.net>
Acked-by: Takashi Iwai <tiwai@suse.de>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Anton Vorontsov <anton@enomsg.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Colin Cross <ccross@android.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: James E.J. Bottomley <JBottomley@odin.com>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Kristen Carlson Accardi <kristen@linux.intel.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Suma Ramars <sramars@cisco.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We use pat_enabled in x86-specific code to see if PAT is enabled
or not but we're granting full access to it even though readers
do not need to set it. If, for instance, we granted access to it
to modules later they then could override the variable
setting... no bueno.
This renames pat_enabled to a new static variable __pat_enabled.
Folks are redirected to use pat_enabled() now.
Code that sets this can only be internal to pat.c. Apart from
the early kernel parameter "nopat" to disable PAT, we also have
a few cases that disable it later and make use of a helper
pat_disable(). It is wrapped under an ifdef but since that code
cannot run unless PAT was enabled its not required to wrap it
with ifdefs, unwrap that. Likewise, since "nopat" doesn't really
change non-PAT systems just remove that ifdef as well.
Although we could add and use an early_param_off(), these
helpers don't use __read_mostly but we want to keep
__read_mostly for __pat_enabled as this is a hot path -- upon
boot, for instance, a simple guest may see ~4k accesses to
pat_enabled(). Since __read_mostly early boot params are not
that common we don't add a helper for them just yet.
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Walls <awalls@md.metrocast.net>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Doug Ledford <dledford@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kyle McMartin <kyle@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1430425520-22275-3-git-send-email-mcgrof@do-not-panic.com
Link: http://lkml.kernel.org/r/1432628901-18044-13-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The patch doesn't change any logic.
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1429776428-4475-1-git-send-email-decui@microsoft.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
ioremap_nocache() currently uses UC- by default. Our goal is to
eventually make UC the default. Linux maps UC- to PCD=1, PWT=0
page attributes on non-PAT systems. Linux maps UC to PCD=1,
PWT=1 page attributes on non-PAT systems. On non-PAT and PAT
systems a WC MTRR has different effects on pages with either of
these attributes. In order to help with a smooth transition its
best to enable use of UC (PCD,1, PWT=1) on a region as that
ensures a WC MTRR will have no effect on a region, this however
requires us to have an way to declare a region as UC and we
currently do not have a way to do this.
WC MTRR on non-PAT system with PCD=1, PWT=0 (UC-) yields WC.
WC MTRR on non-PAT system with PCD=1, PWT=1 (UC) yields UC.
WC MTRR on PAT system with PCD=1, PWT=0 (UC-) yields WC.
WC MTRR on PAT system with PCD=1, PWT=1 (UC) yields UC.
A flip of the default ioremap_nocache() behaviour from UC- to UC
can therefore regress a memory region from effective memory type
WC to UC if MTRRs are used. Use of MTRRs should be phased out
and in the best case only arch_phys_wc_add() use will remain,
even if this happens arch_phys_wc_add() will have an effect on
non-PAT systems and changes to default ioremap_nocache()
behaviour could regress drivers.
Now, ideally we'd use ioremap_nocache() on the regions in which
we'd need uncachable memory types and avoid any MTRRs on those
regions. There are however some restrictions on MTRRs use, such
as the requirement of having the base and size of variable sized
MTRRs to be powers of two, which could mean having to use a WC
MTRR over a large area which includes a region in which
write-combining effects are undesirable.
Add ioremap_uc() to help with the both phasing out of MTRR use
and also provide a way to blacklist small WC undesirable regions
in devices with mixed regions which are size-implicated to use
large WC MTRRs. Use of ioremap_uc() helps phase out MTRR use by
avoiding regressions with an eventual flip of default behaviour
or ioremap_nocache() from UC- to UC.
Drivers working with WC MTRRs can use the below table to review
and consider the use of ioremap*() and similar helpers to ensure
appropriate behaviour long term even if default
ioremap_nocache() behaviour changes from UC- to UC.
Although ioremap_uc() is being added we leave set_memory_uc() to
use UC- as only initial memory type setup is required to be able
to accommodate existing device drivers and phase out MTRR use.
It should also be clarified that set_memory_uc() cannot be used
with IO memory, even though its use will not return any errors,
it really has no effect.
----------------------------------------------------------------------
MTRR Non-PAT PAT Linux ioremap value Effective memory type
----------------------------------------------------------------------
Non-PAT | PAT
PAT
|PCD
||PWT
|||
WC 000 WB _PAGE_CACHE_MODE_WB WC | WC
WC 001 WC _PAGE_CACHE_MODE_WC WC* | WC
WC 010 UC- _PAGE_CACHE_MODE_UC_MINUS WC* | WC
WC 011 UC _PAGE_CACHE_MODE_UC UC | UC
----------------------------------------------------------------------
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Antonino Daplas <adaplas@gmail.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Travis <travis@sgi.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Suresh Siddha <sbsiddha@gmail.com>
Cc: Thierry Reding <treding@nvidia.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Ville Syrjälä <syrjala@sci.fi>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-fbdev@vger.kernel.org
Link: http://lkml.kernel.org/r/1430343851-967-2-git-send-email-mcgrof@do-not-panic.com
Link: http://lkml.kernel.org/r/1431332153-18566-9-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The current algorithm used in clflush_cache_range() can cause
the last cache line of the buffer to be flushed twice. Fix that
algorithm so that each cache line will only be flushed once.
Reported-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Toshi Kani <toshi.kani@hp.com>
Link: http://lkml.kernel.org/r/1430259192-18802-1-git-send-email-ross.zwisler@linux.intel.com
Link: http://lkml.kernel.org/r/1431332153-18566-5-git-send-email-bp@alien8.de
[ Changed it to 'void *' to simplify the type conversions. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
direct_gbpages can be force enabled as an early parameter
but not really have taken effect when DEBUG_PAGEALLOC
or KMEMCHECK is enabled. You can also enable direct_gbpages
right now if you have an x86_64 architecture but your CPU
doesn't really have support for this feature. In both cases
PG_LEVEL_1G won't actually be enabled but direct_gbpages is used
in other areas under the assumptions that PG_LEVEL_1G
was set. Fix this by putting together all requirements
which make this feature sensible to enable under, and only
enable both finally flipping on PG_LEVEL_1G and leaving
PG_LEVEL_1G set when this is true.
We only enable this feature then to be possible on sensible
builds defined by the new ENABLE_DIRECT_GBPAGES. If the
CPU has support for it you can either enable this by using
the DIRECT_GBPAGES option or using the early kernel parameter.
If a platform had support for this you can always force disable
it as well.
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: JBeulich@suse.com
Cc: Jan Beulich <JBeulich@suse.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: julia.lawall@lip6.fr
Link: http://lkml.kernel.org/r/1425518654-3403-3-git-send-email-mcgrof@do-not-panic.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This effectively unexports set_memory_ro() and set_memory_rw()
functions, and thus reverts:
a03352d2c1 ("x86: export set_memory_ro and set_memory_rw").
They have been introduced for debugging purposes in e1000e, but
no module user is in mainline kernel (anymore?) and we
explicitly do not want modules to use these functions, as they
i.e. protect eBPF (interpreted & JIT'ed) images from malicious
modifications or bugs.
Outside of eBPF scope, I believe also other set_memory_*()
functions should be unexported on x86 for modules.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Bruce Allan <bruce.w.allan@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jesse Brandeburg <jesse.brandeburg@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: davem@davemloft.net
Link: http://lkml.kernel.org/r/a064393a0a5d319eebde5c761cfd743132d4f213.1425040940.git.daniel@iogearbox.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
- Linear p2m for x86 PV guests which simplifies the p2m code, improves
performance and will allow for > 512 GB PV guests in the future.
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Merge tag 'stable/for-linus-3.19-rc0b-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull additional xen update from David Vrabel:
"Xen: additional features for 3.19-rc0
- Linear p2m for x86 PV guests which simplifies the p2m code,
improves performance and will allow for > 512 GB PV guests in the
future.
A last-minute, configuration specific issue was discovered with this
change which is why it was not included in my previous pull request.
This is now been fixed and tested"
* tag 'stable/for-linus-3.19-rc0b-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
xen: switch to post-init routines in xen mmu.c earlier
Revert "swiotlb-xen: pass dev_addr to swiotlb_tbl_unmap_single"
xen: annotate xen_set_identity_and_remap_chunk() with __init
xen: introduce helper functions to do safe read and write accesses
xen: Speed up set_phys_to_machine() by using read-only mappings
xen: switch to linear virtual mapped sparse p2m list
xen: Hide get_phys_to_machine() to be able to tune common path
x86: Introduce function to get pmd entry pointer
xen: Delay invalidating extra memory
xen: Delay m2p_override initialization
xen: Delay remapping memory of pv-domain
xen: use common page allocation function in p2m.c
xen: Make functions static
xen: fix some style issues in p2m.c
Now, we have prepared to avoid using debug-pagealloc in boottime. So
introduce new kernel-parameter to disable debug-pagealloc in boottime, and
makes related functions to be disabled in this case.
Only non-intuitive part is change of guard page functions. Because guard
page is effective only if debug-pagealloc is enabled, turning off
according to debug-pagealloc is reasonable thing to do.
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Dave Hansen <dave@sr71.net>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Jungsoo Son <jungsoo.son@lge.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull x86 mm tree changes from Ingo Molnar:
"The biggest change is full PAT support from Jürgen Gross:
The x86 architecture offers via the PAT (Page Attribute Table) a
way to specify different caching modes in page table entries. The
PAT MSR contains 8 entries each specifying one of 6 possible cache
modes. A pte references one of those entries via 3 bits:
_PAGE_PAT, _PAGE_PWT and _PAGE_PCD.
The Linux kernel currently supports only 4 different cache modes.
The PAT MSR is set up in a way that the setting of _PAGE_PAT in a
pte doesn't matter: the top 4 entries in the PAT MSR are the same
as the 4 lower entries.
This results in the kernel not supporting e.g. write-through mode.
Especially this cache mode would speed up drivers of video cards
which now have to use uncached accesses.
OTOH some old processors (Pentium) don't support PAT correctly and
the Xen hypervisor has been using a different PAT MSR configuration
for some time now and can't change that as this setting is part of
the ABI.
This patch set abstracts the cache mode from the pte and introduces
tables to translate between cache mode and pte bits (the default
cache mode "write back" is hard-wired to PAT entry 0). The tables
are statically initialized with values being compatible to old
processors and current usage. As soon as the PAT MSR is changed
(or - in case of Xen - is read at boot time) the tables are changed
accordingly. Requests of mappings with special cache modes are
always possible now, in case they are not supported there will be a
fallback to a compatible but slower mode.
Summing it up, this patch set adds the following features:
- capability to support WT and WP cache modes on processors with
full PAT support
- processors with no or uncorrect PAT support are still working as
today, even if WT or WP cache mode are selected by drivers for
some pages
- reduction of Xen special handling regarding cache mode
Another change is a boot speedup on ridiculously large RAM systems,
plus other smaller fixes"
* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (22 commits)
x86: mm: Move PAT only functions to mm/pat.c
xen: Support Xen pv-domains using PAT
x86: Enable PAT to use cache mode translation tables
x86: Respect PAT bit when copying pte values between large and normal pages
x86: Support PAT bit in pagetable dump for lower levels
x86: Clean up pgtable_types.h
x86: Use new cache mode type in memtype related functions
x86: Use new cache mode type in mm/ioremap.c
x86: Use new cache mode type in setting page attributes
x86: Remove looking for setting of _PAGE_PAT_LARGE in pageattr.c
x86: Use new cache mode type in track_pfn_remap() and track_pfn_insert()
x86: Use new cache mode type in mm/iomap_32.c
x86: Use new cache mode type in asm/pgtable.h
x86: Use new cache mode type in arch/x86/mm/init_64.c
x86: Use new cache mode type in arch/x86/pci
x86: Use new cache mode type in drivers/video/fbdev/vermilion
x86: Use new cache mode type in drivers/video/fbdev/gbefb.c
x86: Use new cache mode type in include/asm/fb.h
x86: Make page cache mode a real type
x86: mm: Use 2GB memory block size on large-memory x86-64 systems
...
Introduces lookup_pmd_address() to get the address of the pmd entry
related to a virtual address in the current address space. This
function is needed for support of a virtual mapped sparse p2m list
in xen pv domains, as we need the address of the pmd entry, not the
one of the pte in that case.
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
