linux.git/arch/mips/kernel/setup.c, branch v4.11

MIPS: kexec: Do not reserve invalid crashkernel memory on boot

2017-01-03T15:34:46+00:00

Do not reserve memory for the crashkernel if the commandline argument
points to a wrong location. This can happen if the location is specified
wrong or if the same commandline is reused when starting the crashkernel
- in the latter case the reserved memory would point to the location
from which the crashkernel is executing.

Signed-off-by: Marcin Nowakowski 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14612/
Signed-off-by: Ralf Baechle

MIPS: fix mem=X@Y commandline processing

2017-01-03T15:34:45+00:00

When a memory offset is specified through the commandline, add the
memory in range PHYS_OFFSET:Y as reserved memory area.
Otherwise the bootmem allocator is initialised with low page equal to
min_low_pfn = PHYS_OFFSET, and in free_all_bootmem will process pages
starting from min_low_pfn instead of PFN(Y).

Signed-off-by: Marcin Nowakowski 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14613/
Signed-off-by: Ralf Baechle

MIPS: Use early_init_fdt_reserve_self to protect DTB location

2017-01-03T15:34:45+00:00

early_init_fdt_reserve_self is used to tell the boot memory allocator
that a memory is occupied by the DTB, so add it in the MIPS init code to
ensure information about the DTB is added to the boot memory array.

Signed-off-by: Marcin Nowakowski 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14610/
Signed-off-by: Ralf Baechle

MIPS: init: Ensure bootmem does not corrupt reserved memory

2017-01-03T15:34:45+00:00

Current init code initialises bootmem allocator with all of the low
memory that it assumes is available, but does not check for reserved
memory block, which can lead to corruption of data that may be stored
there.
Move bootmem's allocation map to a location that does not cross any
reserved regions

Signed-off-by: Marcin Nowakowski 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14609/
Signed-off-by: Ralf Baechle

MIPS: init: Ensure reserved memory regions are not added to bootmem

2017-01-03T15:34:45+00:00

Memories managed through boot_mem_map are generally expected to define
non-crossing areas. However, if part of a larger memory block is marked
as reserved, it would still be added to bootmem allocator as an
available block and could end up being overwritten by the allocator.

Prevent this by explicitly marking the memory as reserved it if exists
in the range used by bootmem allocator.

Signed-off-by: Marcin Nowakowski 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14608/
Signed-off-by: Ralf Baechle

MIPS: Do not request resources for crashkernel if one isn't defined

2017-01-03T15:34:44+00:00

When KEXEC is enabled but crashkernel details are not passed through the
kernel commandline unnecessary resources are requested (start==end==0)

Signed-off-by: Marcin Nowakowski 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14607/
Signed-off-by: Ralf Baechle

MIPS: Fix max_low_pfn with disabled highmem

2016-11-04T00:45:22+00:00

When low memory doesn't reach HIGHMEM_START (e.g. up to 256MB at PA=0 is
common) and highmem is present above HIGHMEM_START (e.g. on Malta the
RAM overlayed by the IO region is aliased at PA=0x90000000), max_low_pfn
will be initially calculated very large and then clipped down to
HIGHMEM_START.

This causes crashes when reading /sys/kernel/mm/page_idle/bitmap
(i.e. CONFIG_IDLE_PAGE_TRACKING=y) when highmem is disabled. pfn_valid()
will compare against max_mapnr which is derived from max_low_pfn when
there is no highend_pfn set up, and will return true for PFNs right up
to HIGHMEM_START, even though they are beyond the end of low memory and
no page structs will actually exist for these PFNs.

This is fixed by skipping high memory regions when initially calculating
max_low_pfn if highmem is disabled, so it doesn't get clipped too high.
We also clip regions which overlap the highmem boundary when highmem is
disabled, so that max_pfn doesn't extend into highmem either.

Signed-off-by: James Hogan 
Cc: Paul Burton 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14490/
Signed-off-by: Ralf Baechle

MIPS: Fix detection of unsupported highmem with cache aliases

2016-09-29T16:59:49+00:00

The paging_init() function contains code which detects that highmem is
in use but unsupported due to dcache aliasing. However this code was
ineffective because it was being run before the caches are probed,
meaning that cpu_has_dc_aliases would always evaluate to false (unless a
platform overrides it to a compile-time constant) and the detection of
the unsupported case is never triggered. The kernel would then go on to
attempt to use highmem & either hit coherency issues or trigger the
BUG_ON in flush_kernel_dcache_page().

Fix this by running paging_init() later than cpu_cache_init(), such that
the cpu_has_dc_aliases macro will evaluate correctly & the unsupported
highmem case will be detected successfully.

This then leads to a formerly hidden issue in that
mem_init_free_highmem() will attempt to free all highmem pages, even
though we're avoiding use of them & don't have valid page structs for
them. This leads to an invalid pointer dereference & a TLB exception.
Avoid this by skipping the loop in mem_init_free_highmem() if
cpu_has_dc_aliases evaluates true.

Signed-off-by: Paul Burton 
Cc: Rabin Vincent 
Cc: Matt Redfearn 
Cc: Jerome Marchand 
Cc: Alexander Sverdlin 
Cc: Aurelien Jarno 
Cc: Jaedon Shin 
Cc: Toshi Kani 
Cc: James Hogan 
Cc: Sergey Ryazanov 
Cc: Jonas Gorski 
Cc: Kirill A. Shutemov 
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/14184/
Signed-off-by: Ralf Baechle

MIPS: Fix memory regions reaching top of physical

2016-09-13T12:13:26+00:00

Memory regions added with add_memory_region() at the top of the physical
address space will have their end address overflow to 0. This causes
them to be rejected as invalid, and would cause various other issues
later on.

This causes issues on Malta and Boston platforms when wanting to use all
2GB of RAM on a 32-bit kernel, either via highmem (using physical
addresses 0x90000000..0xFFFFFFFF), or with the Malta Enhanced Virtual
Addressing (EVA) layout which exposes the whole 0x80000000..0xFFFFFFFF
physical address range to kernel mode at 0x00000000..0x7FFFFFFF.

Due to the abundance of these non-overflow assumptions and the fact that
memblock already avoids the arithmetic overflow by limiting the size of
new memory regions without the arch code knowing it (in particular
mem_init_free_highmem() will trigger a page dump due to nonzero mapcount
on the last page), it is simpler and safer to just limit the size of the
region in a similar way to memblock but at the arch level to allow most
of the RAM to be used without arithmetic overflows.

Therefore we detect this case specifically and reduce the size of the
region slightly to avoid the arithmetic overflows and cause the last
page to be ignored.

Signed-off-by: James Hogan 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/13857/
Signed-off-by: Ralf Baechle

MIPS: store the appended dtb address in a variable

2016-08-02T12:00:16+00:00

Instead of rewriting the arguments to match the UHI spec, store the
address of a appended or UHI supplied dtb in fw_supplied_dtb.

That way the original bootloader arugments are kept intact while still
making the use of an appended dtb invisible for mach code.

Mach code can still find out if it is an appended dtb by comparing
fw_arg1 with fw_supplied_dtb.

Signed-off-by: Jonas Gorski 
Cc: Kevin Cernekee 
Cc: Florian Fainelli 
Cc: John Crispin 
Cc: Paul Burton 
Cc: James Hogan 
Cc: Alban Bedel 
Cc: Daniel Gimpelevich 
Cc: Antony Pavlov 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/13699/
Signed-off-by: Ralf Baechle