linux/arch/arm64/mm
Ard Biesheuvel 9fdc14c55c arm64: mm: fix location of _etext
As Kees Cook notes in the ARM counterpart of this patch [0]:

  The _etext position is defined to be the end of the kernel text code,
  and should not include any part of the data segments. This interferes
  with things that might check memory ranges and expect executable code
  up to _etext.

In particular, Kees is referring to the HARDENED_USERCOPY patch set [1],
which rejects attempts to call copy_to_user() on kernel ranges containing
executable code, but does allow access to the .rodata segment. Regardless
of whether one may or may not agree with the distinction, it makes sense
for _etext to have the same meaning across architectures.

So let's put _etext where it belongs, between .text and .rodata, and fix
up existing references to use __init_begin instead, which unlike _end_rodata
includes the exception and notes sections as well.

The _etext references in kaslr.c are left untouched, since its references
to [_stext, _etext) are meant to capture potential jump instruction targets,
and so disregarding .rodata is actually an improvement here.

[0] http://article.gmane.org/gmane.linux.kernel/2245084
[1] http://thread.gmane.org/gmane.linux.kernel.hardened.devel/2502

Reported-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2016-06-27 18:21:27 +01:00
..
cache.S arm64: Fold proc-macros.S into assembler.h 2016-04-28 12:05:45 +01:00
context.c arm64: Add cpu_panic_kernel helper 2016-04-15 18:06:06 +01:00
copypage.c arm64: Defer dcache flush in __cpu_copy_user_page 2015-12-17 11:07:13 +00:00
dma-mapping.c arm64: mm: only initialize swiotlb when necessary 2016-06-21 16:54:53 +01:00
dump.c arm64: mm: dump: make page table dumping reusable 2016-06-21 15:09:11 +01:00
extable.c arm64: switch to relative exception tables 2016-02-24 14:57:26 +00:00
fault.c arm64: kill ESR_LNX_EXEC 2016-06-21 17:07:48 +01:00
flush.c arm64: mm: allow preemption in copy_to_user_page 2016-03-24 16:32:54 +00:00
hugetlbpage.c Revert "arm64: hugetlb: partial revert of 66b3923a1a0f" 2016-05-31 11:00:09 +01:00
init.c arm64: mm: fix location of _etext 2016-06-27 18:21:27 +01:00
ioremap.c arm64: add ioremap physical address information 2015-01-23 15:29:06 +00:00
kasan_init.c arm64: kasan: Fix zero shadow mapping overriding kernel image shadow 2016-03-11 11:03:35 +00:00
Makefile arm64, numa: Add NUMA support for arm64 platforms. 2016-04-15 18:06:09 +01:00
mm.h arm64: Move unflatten_device_tree() call earlier. 2016-04-15 18:06:08 +01:00
mmap.c arm64: mm: remove unnecessary EXPORT_SYMBOL_GPL 2016-05-05 09:49:38 +01:00
mmu.c arm64: mm: fix location of _etext 2016-06-27 18:21:27 +01:00
numa.c arm64, numa: Add NUMA support for arm64 platforms. 2016-04-15 18:06:09 +01:00
pageattr.c arm64: Add support for ARCH_SUPPORTS_DEBUG_PAGEALLOC 2016-02-16 15:40:30 +00:00
pgd.c arm64: mm: move pgd_cache initialisation to pgtable_cache_init 2016-01-05 15:43:10 +00:00
proc.S arm64: Change cpu_resume() to enable mmu early then access sleep_sp by va 2016-04-28 12:05:46 +01:00