The discussion about using "access_ok()" in get_user_pages_fast() (see
commit 7f81890687: "x86: don't use
'access_ok()' as a range check in get_user_pages_fast()" for details and
end result), made us notice that x86-64 was really being very sloppy
about virtual address checking.
So be way more careful and straightforward about masking x86-64 virtual
addresses:
- All the VIRTUAL_MASK* variants now cover half of the address
space, it's not like we can use the full mask on a signed
integer, and the larger mask just invites mistakes when
applying it to either half of the 48-bit address space.
- /proc/kcore's kc_offset_to_vaddr() becomes a lot more
obvious when it transforms a file offset into a
(kernel-half) virtual address.
- Unify/simplify the 32-bit and 64-bit USER_DS definition to
be based on TASK_SIZE_MAX.
This cleanup and more careful/obvious user virtual address checking also
uncovered a buglet in the x86-64 implementation of strnlen_user(): it
would do an "access_ok()" check on the whole potential area, even if the
string itself was much shorter, and thus return an error even for valid
strings. Our sloppy checking had hidden this.
So this fixes 'strnlen_user()' to do this properly, the same way we
already handled user strings in 'strncpy_from_user()'. Namely by just
checking the first byte, and then relying on fault handling for the
rest. That always works, since we impose a guard page that cannot be
mapped at the end of the user space address space (and even if we
didn't, we'd have the address space hole).
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (22 commits)
x86: fix system without memory on node0
x86, mm: Fix node_possible_map logic
mm, x86: remove MEMORY_HOTPLUG_RESERVE related code
x86: make sparse mem work in non-NUMA mode
x86: process.c, remove useless headers
x86: merge process.c a bit
x86: use sparse_memory_present_with_active_regions() on UMA
x86: unify 64-bit UMA and NUMA paging_init()
x86: Allow 1MB of slack between the e820 map and SRAT, not 4GB
x86: Sanity check the e820 against the SRAT table using e820 map only
x86: clean up and and print out initial max_pfn_mapped
x86/pci: remove rounding quirk from e820_setup_gap()
x86, e820, pci: reserve extra free space near end of RAM
x86: fix typo in address space documentation
x86: 46 bit physical address support on 64 bits
x86, mm: fault.c, use printk_once() in is_errata93()
x86: move per-cpu mmu_gathers to mm/init.c
x86: move max_pfn_mapped and max_low_pfn_mapped to setup.c
x86: unify noexec handling
x86: remove (null) in /sys kernel_page_tables
...
Handle the misconfiguration where CONFIG_PHYSICAL_START is
incompatible with CONFIG_PHYSICAL_ALIGN. This is a configuration
error, but one which arises easily since Kconfig doesn't have the
smarts to express the true relationship between these two variables.
Hence, align __PHYSICAL_START the same way we align LOAD_PHYSICAL_ADDR
in <asm/boot.h>.
For non-relocatable kernels, this would cause the boot to fail.
[ Impact: fix boot failures for non-relocatable kernels ]
Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Extend the maximum addressable memory on x86-64 from 2^44 to
2^46 bytes. This requires some shuffling around of the vmalloc
and virtual memmap memory areas, to keep them away from the
direct mapping of up to 64TB of physical memory.
This patch also introduces a guard hole between the vmalloc
area and the virtual memory map space. There's really no
good reason why we wouldn't have a guard hole there.
[ Impact: future hardware enablement ]
Signed-off-by: Rik van Riel <riel@redhat.com>
LKML-Reference: <20090505172856.6820db22@cuia.bos.redhat.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Impact: unification of declarations, cleanup
Unification of declarations:
moved init_memory_mapping, initmem_init and free_initmem from
page_XX_types.h to page_types.h
Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <1239693869.3033.31.camel@ht.satnam>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
pgtable*.h is intended for definitions relating to actual pagetables
and their entries, so move all the definitions for
(pte|pmd|pud|pgd)(val)?_t to the appropriate pgtable*.h headers.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
