linux-stable.git/arch/mips/kernel/setup.c, branch v4.14.331

mips/cpu: Switch to arch_cpu_finalize_init()

2023-08-08T17:48:23+00:00

commit 7f066a22fe353a827a402ee2835e81f045b1574d upstream

check_bugs() is about to be phased out. Switch over to the new
arch_cpu_finalize_init() implementation.

No functional change.

Signed-off-by: Thomas Gleixner 
Link: https://lore.kernel.org/r/20230613224545.312438573@linutronix.de
Signed-off-by: Daniel Sneddon 
Signed-off-by: Greg Kroah-Hartman

mips: Move initrd_start check after initrd address sanitisation.

2023-06-21T13:38:57+00:00

[ Upstream commit 4897a898a216058dec55e5e5902534e6e224fcdf ]

PAGE_OFFSET is technically a virtual address so when checking the value of
initrd_start against it we should make sure that it has been sanitised from
the values passed by the bootloader. Without this change, even with a bootloader
that passes correct addresses for an initrd, we are failing to load it on MT7621
boards, for example.

Signed-off-by: Liviu Dudau 
Signed-off-by: Thomas Bogendoerfer 
Signed-off-by: Sasha Levin

MIPS: Make sparse_init() using top-down allocation

2020-06-20T08:25:10+00:00

[ Upstream commit 269b3a9ac538c4ae87f84be640b9fa89914a2489 ]

In the current code, if CONFIG_SWIOTLB is set, when failed to get IO TLB
memory from the low pages by plat_swiotlb_setup(), it may lead to the boot
process failed with kernel panic.

(1) On the Loongson and SiByte platform
arch/mips/loongson64/dma.c
arch/mips/sibyte/common/dma.c
void __init plat_swiotlb_setup(void)
{
	swiotlb_init(1);
}

kernel/dma/swiotlb.c
void  __init
swiotlb_init(int verbose)
{
...
	vstart = memblock_alloc_low(PAGE_ALIGN(bytes), PAGE_SIZE);
	if (vstart && !swiotlb_init_with_tbl(vstart, io_tlb_nslabs, verbose))
		return;
...
	pr_warn("Cannot allocate buffer");
	no_iotlb_memory = true;
}

phys_addr_t swiotlb_tbl_map_single()
{
...
	if (no_iotlb_memory)
		panic("Can not allocate SWIOTLB buffer earlier ...");
...
}

(2) On the Cavium OCTEON platform
arch/mips/cavium-octeon/dma-octeon.c
void __init plat_swiotlb_setup(void)
{
...
	octeon_swiotlb = memblock_alloc_low(swiotlbsize, PAGE_SIZE);
	if (!octeon_swiotlb)
		panic("%s: Failed to allocate %zu bytes align=%lx\n",
		      __func__, swiotlbsize, PAGE_SIZE);
...
}

Because IO_TLB_DEFAULT_SIZE is 64M, if the rest size of low memory is less
than 64M when call plat_swiotlb_setup(), we can easily reproduce the panic
case.

In order to reduce the possibility of kernel panic when failed to get IO
TLB memory under CONFIG_SWIOTLB, it is better to allocate low memory as
small as possible before plat_swiotlb_setup(), so make sparse_init() using
top-down allocation.

Reported-by: Juxin Gao 
Co-developed-by: Juxin Gao 
Signed-off-by: Juxin Gao 
Signed-off-by: Tiezhu Yang 
Signed-off-by: Thomas Bogendoerfer 
Signed-off-by: Sasha Levin

mips: avoid explicit UB in assignment of mips_io_port_base

2020-01-27T13:46:44+00:00

[ Upstream commit 12051b318bc3ce5b42d6d786191008284b067d83 ]

The code in question is modifying a variable declared const through
pointer manipulation.  Such code is explicitly undefined behavior, and
is the lone issue preventing malta_defconfig from booting when built
with Clang:

If an attempt is made to modify an object defined with a const-qualified
type through use of an lvalue with non-const-qualified type, the
behavior is undefined.

LLVM is removing such assignments. A simple fix is to not declare
variables const that you plan on modifying.  Limiting the scope would be
a better method of preventing unwanted writes to such a variable.

Further, the code in question mentions "compiler bugs" without any links
to bug reports, so it is difficult to know if the issue is resolved in
GCC. The patch was authored in 2006, which would have been GCC 4.0.3 or
4.1.1. The minimal supported version of GCC in the Linux kernel is
currently 4.6.

For what its worth, there was UB before the commit in question, it just
added a barrier and got lucky IRT codegen. I don't think there's any
actual compiler bugs related, just runtime bugs due to UB.

Link: https://github.com/ClangBuiltLinux/linux/issues/610
Fixes: 966f4406d903 ("[MIPS] Work around bad code generation for .")
Reported-by: Nathan Chancellor 
Debugged-by: Nathan Chancellor 
Suggested-by: Eli Friedman 
Signed-off-by: Nick Desaulniers 
Reviewed-by: Nathan Chancellor 
Tested-by: Nathan Chancellor 
Signed-off-by: Paul Burton 
Cc: ralf@linux-mips.org
Cc: jhogan@kernel.org
Cc: Maciej W. Rozycki 
Cc: Hassan Naveed 
Cc: Stephen Kitt 
Cc: Serge Semin 
Cc: Mike Rapoport 
Cc: Andrew Morton 
Cc: Michal Hocko 
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: clang-built-linux@googlegroups.com
Signed-off-by: Sasha Levin

MIPS: Fix incorrect mem=X@Y handling

2018-02-22T14:42:27+00:00

commit 67a3ba25aa955198196f40b76b329b3ab9ad415a upstream.

Commit 73fbc1eba7ff ("MIPS: fix mem=X@Y commandline processing") added a
fix to ensure that the memory range between PHYS_OFFSET and low memory
address specified by mem= cmdline argument is not later processed by
free_all_bootmem.  This change was incorrect for systems where the
commandline specifies more than 1 mem argument, as it will cause all
memory between PHYS_OFFSET and each of the memory offsets to be marked
as reserved, which results in parts of the RAM marked as reserved
(Creator CI20's u-boot has a default commandline argument 'mem=256M@0x0
mem=768M@0x30000000').

Change the behaviour to ensure that only the range between PHYS_OFFSET
and the lowest start address of the memories is marked as protected.

This change also ensures that the range is marked protected even if it's
only defined through the devicetree and not only via commandline
arguments.

Reported-by: Mathieu Malaterre 
Signed-off-by: Marcin Nowakowski 
Fixes: 73fbc1eba7ff ("MIPS: fix mem=X@Y commandline processing")
Cc: Ralf Baechle 
Cc: linux-mips@linux-mips.org
Cc:  # v4.11+
Tested-by: Mathieu Malaterre 
Patchwork: https://patchwork.linux-mips.org/patch/18562/
Signed-off-by: James Hogan 
Signed-off-by: Greg Kroah-Hartman

MIPS: cmdline: Add support for 'memmap' parameter

2017-06-29T00:42:23+00:00

Implement support for parsing 'memmap' kernel command line parameter.

This patch covers parsing of the following two formats for 'memmap'
parameter values:

  - nn[KMG]@ss[KMG]
  - nn[KMG]$ss[KMG]

  ([KMG] = K M or G (kilo, mega, giga))

These two allowed formats for parameter value are already documented
in file kernel-parameters.txt in Documentation/admin-guide folder.
Some architectures already support them, but Mips did not prior to
this patch.

Excerpt from Documentation/admin-guide/kernel-parameters.txt:

memmap=nn[KMG]@ss[KMG]
    [KNL] Force usage of a specific region of memory.
    Region of memory to be used is from ss to ss+nn.

memmap=nn[KMG]$ss[KMG]
    Mark specific memory as reserved.
    Region of memory to be reserved is from ss to ss+nn.
    Example: Exclude memory from 0x18690000-0x1869ffff
        memmap=64K$0x18690000
        or
        memmap=0x10000$0x18690000

There is no need to update this documentation file with respect to
this patch.

Signed-off-by: Miodrag Dinic 
Signed-off-by: Goran Ferenc 
Signed-off-by: Aleksandar Markovic 
Cc: James.Hogan@imgtec.com
Cc: Paul.Burton@imgtec.com
Cc: Raghu.Gandham@imgtec.com
Cc: Leonid.Yegoshin@imgtec.com
Cc: Douglas.Leung@imgtec.com
Cc: Petar.Jovanovic@imgtec.com
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16508/
Signed-off-by: Ralf Baechle

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