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  1. 16 2月, 2016 9 次提交
  3. 12 12月, 2015 1 次提交
    • W
      arm64: mm: ensure that the zero page is visible to the page table walker · 32d63978
      由 Will Deacon 提交于 
      In paging_init, we allocate the zero page, memset it to zero and then
point TTBR0 to it in order to avoid speculative fetches through the
identity mapping.

In order to guarantee that the freshly zeroed page is indeed visible to
the page table walker, we need to execute a dsb instruction prior to
writing the TTBR.

Cc: <stable@vger.kernel.org> # v3.14+, for older kernels need to drop the 'ishst'
Signed-off-by: NWill Deacon <will.deacon@arm.com>
      32d63978
  5. 11 12月, 2015 1 次提交
  7. 10 12月, 2015 1 次提交
  9. 01 12月, 2015 2 次提交
  11. 26 11月, 2015 1 次提交
    • C
      Revert "arm64: Mark kernel page ranges contiguous" · 667c2759
      由 Catalin Marinas 提交于 
      This reverts commit 348a65cd.

Incorrect page table manipulation that does not respect the ARM ARM
recommended break-before-make sequence may lead to TLB conflicts. The
contiguous PTE patch makes the system even more susceptible to such
errors by changing the mapping from a single page to a contiguous range
of pages. An additional TLB invalidation would reduce the risk window,
however, the correct fix is to switch to a temporary swapper_pg_dir.
Once the correct workaround is done, the reverted commit will be
re-applied.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Reported-by: NJeremy Linton <jeremy.linton@arm.com>
      667c2759
  13. 25 11月, 2015 1 次提交
  15. 18 11月, 2015 1 次提交
  17. 17 11月, 2015 1 次提交
    • A
      arm64: mm: use correct mapping granularity under DEBUG_RODATA · 4fee9f36
      由 Ard Biesheuvel 提交于 
      When booting a 64k pages kernel that is built with CONFIG_DEBUG_RODATA
and resides at an offset that is not a multiple of 512 MB, the rounding
that occurs in __map_memblock() and fixup_executable() results in
incorrect regions being mapped.

The following snippet from /sys/kernel/debug/kernel_page_tables shows
how, when the kernel is loaded 2 MB above the base of DRAM at 0x40000000,
the first 2 MB of memory (which may be inaccessible from non-secure EL1
or just reserved by the firmware) is inadvertently mapped into the end of
the module region.

  ---[ Modules start ]---
  0xfffffdffffe00000-0xfffffe0000000000     2M RW NX ... UXN MEM/NORMAL
  ---[ Modules end ]---
  ---[ Kernel Mapping ]---
  0xfffffe0000000000-0xfffffe0000090000   576K RW NX ... UXN MEM/NORMAL
  0xfffffe0000090000-0xfffffe0000200000  1472K ro x  ... UXN MEM/NORMAL
  0xfffffe0000200000-0xfffffe0000800000     6M ro x  ... UXN MEM/NORMAL
  0xfffffe0000800000-0xfffffe0000810000    64K ro x  ... UXN MEM/NORMAL
  0xfffffe0000810000-0xfffffe0000a00000  1984K RW NX ... UXN MEM/NORMAL
  0xfffffe0000a00000-0xfffffe00ffe00000  4084M RW NX ... UXN MEM/NORMAL

The same issue is likely to occur on 16k pages kernels whose load
address is not a multiple of 32 MB (i.e., SECTION_SIZE). So round to
SWAPPER_BLOCK_SIZE instead of SECTION_SIZE.

Fixes: da141706 ("arm64: add better page protections to arm64")
Signed-off-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: NMark Rutland <mark.rutland@arm.com>
Acked-by: NLaura Abbott <labbott@redhat.com>
Cc: <stable@vger.kernel.org> # 4.0+
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
      4fee9f36
  19. 12 11月, 2015 1 次提交
  21. 09 11月, 2015 2 次提交
  23. 20 10月, 2015 1 次提交
  25. 09 10月, 2015 1 次提交
    • J
      arm64: Mark kernel page ranges contiguous · 348a65cd
      由 Jeremy Linton 提交于 
      With 64k pages, the next larger segment size is 512M. The linux
kernel also uses different protection flags to cover its code and data.
Because of this requirement, the vast majority of the kernel code and
data structures end up being mapped with 64k pages instead of the larger
pages common with a 4k page kernel.

Recent ARM processors support a contiguous bit in the
page tables which allows the a TLB to cover a range larger than a
single PTE if that range is mapped into physically contiguous
ram.

So, for the kernel its a good idea to set this flag. Some basic
micro benchmarks show it can significantly reduce the number of
L1 dTLB refills.

Add boot option to enable/disable CONT marking, as well as fix a
bug found by Steve Capper.
Signed-off-by: NJeremy Linton <jeremy.linton@arm.com>
[catalin.marinas@arm.com: remove CONFIG_ARM64_CONT_PTE altogether]
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
      348a65cd
  27. 07 10月, 2015 1 次提交
  29. 28 7月, 2015 1 次提交
    • M
      arm64: mm: mark create_mapping as __init · c53e0baa
      由 Mark Rutland 提交于 
      Currently create_mapping is marked with __ref, apparently because it
refers to early_alloc. However, create_mapping has no logic to prevent
erroneous use of early_alloc after it has been freed, and is only ever
called by __init functions anyway. Thus the __ref marker is misleading
and unnecessary.

Instead, this patch marks create_mapping as __init, resulting in
warnings if it is used from a a non __init functions, and allowing its
memory to be reclaimed.
Signed-off-by: NMark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
      c53e0baa
  31. 27 7月, 2015 1 次提交
  33. 01 7月, 2015 1 次提交
  35. 02 6月, 2015 1 次提交
  37. 15 4月, 2015 1 次提交
  39. 23 3月, 2015 1 次提交
  41. 19 3月, 2015 1 次提交
  43. 30 1月, 2015 1 次提交
  45. 28 1月, 2015 3 次提交
    • M
      arm64: mm: use *_sect to check for section maps · a1c76574
      由 Mark Rutland 提交于 
      The {pgd,pud,pmd}_bad family of macros have slightly fuzzy
cross-architecture semantics, and seem to imply a populated entry that
is not a next-level table, rather than a particular type of entry (e.g.
a section map).

In arm64 code, for those cases where we care about whether an entry is a
section mapping, we can instead use the {pud,pmd}_sect macros to
explicitly check for this case. This helps to document precisely what we
care about, making the code easier to read, and allows for future
relaxation of the *_bad macros to check for other "bad" entries.

To that end this patch updates the table dumping and initial table setup
to check for section mappings with {pud,pmd}_sect, and adds/restores
BUG_ON(*_bad((*p)) checks after we've handled the *_sect and *_none
cases so as to catch remaining "bad" cases.

In the fault handling code, show_pte is left with *_bad checks as it
only cares about whether it can walk the next level table, and this path
is used for both kernel and userspace fault handling. The former case
will be followed by a die() where we'll report the address that
triggered the fault, which can be useful context for debugging.
Signed-off-by: NMark Rutland <mark.rutland@arm.com>
Acked-by: NSteve Capper <steve.capper@linaro.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Laura Abbott <lauraa@codeaurora.org>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
      a1c76574
    • M
      arm64: drop unnecessary cache+tlb maintenance · a3bba370
      由 Mark Rutland 提交于 
      In paging_init, we call flush_cache_all, but this is backed by Set/Way
operations which may not achieve anything in the presence of cache line
migration and/or system caches. If the caches are already in an
inconsistent state at this point, there is nothing we can do (short of
flushing the entire physical address space by VA) to empty architected
and system caches. As such, flush_cache_all only serves to mask other
potential bugs. Hence, this patch removes the boot-time call to
flush_cache_all.

Immediately after the cache maintenance we flush the TLBs, but this is
also unnecessary. Before enabling the MMU, the TLBs are invalidated, and
thus are initially clean. When changing the contents of active tables
(e.g. in fixup_executable() for DEBUG_RODATA) we perform the required
TLB maintenance following the update, and therefore no additional
maintenance is required to ensure the new table entries are in effect.
Since activating the MMU we will not have modified system register
fields permitted to be cached in a TLB, and therefore do not need
maintenance for any cached system register fields. Hence, the TLB flush
is unnecessary.

Shortly after the unnecessary TLB flush, we update TTBR0 to point to an
empty zero page rather than the idmap, and flush the TLBs. This
maintenance is necessary to remove the global idmap entries from the
TLBs (as they would conflict with userspace mappings), and is retained.
Signed-off-by: NMark Rutland <mark.rutland@arm.com>
Acked-by: NMarc Zyngier <marc.zyngier@arm.com>
Acked-by: NSteve Capper <steve.capper@linaro.org>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
      a3bba370
    • Z
      arm64:mm: free the useless initial page table · 523d6e9f
      由 zhichang.yuan 提交于 
      For 64K page system, after mapping a PMD section, the corresponding initial
page table is not needed any more. That page can be freed.
Signed-off-by: NZhichang Yuan <zhichang.yuan@linaro.org>
[catalin.marinas@arm.com: added BUG_ON() to catch late memblock freeing]
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
      523d6e9f
  47. 22 1月, 2015 2 次提交
  49. 14 1月, 2015 1 次提交
    • M
      arm64: remove broken cachepolicy code · 26a945ca
      由 Mark Rutland 提交于 
      The cachepolicy kernel parameter was intended to aid in the debugging of
coherency issues, but it is fundamentally broken for several reasons:

 * On SMP platforms, only the boot CPU's tcr_el1 is altered. Secondary
   CPUs may therefore use differ w.r.t. the attributes they apply to
   MT_NORMAL memory, resulting in a loss of coherency.

 * The cache maintenance using flush_dcache_all (based on Set/Way
   operations) is not guaranteed to empty a given CPU's cache hierarchy
   while said CPU has caches enabled, it cannot empty the caches of
   other coherent PEs, nor is it guaranteed to flush data to the PoC
   even when caches are disabled.

 * The TLBs are not invalidated around the modification of MAIR_EL1 and
   TCR_EL1, as required by the architecture (as both are permitted to be
   cached in a TLB). This may result in CPUs using attributes other than
   those expected for some memory accesses, resulting in a loss of
   coherency.

 * Exclusive accesses are not architecturally guaranteed to function as
   expected on memory marked as Write-Through or Non-Cacheable. Thus
   changing the attributes of MT_NORMAL away from the (architecurally
   safe) defaults may cause uses of these instructions (e.g. atomics) to
   behave erratically.

Given this, the cachepolicy code cannot be used for debugging purposes
as it alone is likely to cause coherency issues. This patch removes the
broken cachepolicy code.
Signed-off-by: NMark Rutland <mark.rutland@arm.com>
Acked-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
      26a945ca
  51. 13 1月, 2015 1 次提交
  53. 12 1月, 2015 1 次提交