linux-stable.git/arch/mips/kernel/setup.c, branch v5.4

MIPS: init: Prevent adding memory before PHYS_OFFSET

2019-10-02T21:11:30+00:00

On some SGI machines (IP28 and IP30) a small region of memory is mirrored
to pyhsical address 0 for exception vectors while rest of the memory
is reachable at a higher physical address. ARC PROM marks this
region as reserved, but with commit a94e4f24ec83 ("MIPS: init: Drop
boot_mem_map") this chunk is used, when searching for start of ram,
which breaks at least IP28 and IP30 machines. To fix this
add_region_memory() checks for start address < PHYS_OFFSET and ignores
these chunks.

Fixes: a94e4f24ec83 ("MIPS: init: Drop boot_mem_map")
Signed-off-by: Thomas Bogendoerfer 
Signed-off-by: Paul Burton 
Cc: Ralf Baechle 
Cc: James Hogan 
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org

MIPS: init: Fix reservation of memory between PHYS_OFFSET and mem start

2019-10-02T21:10:16+00:00

Fix calculation of the size for reserving memory between PHYS_OFFSET
and real memory start.

Fixes: a94e4f24ec83 ("MIPS: init: Drop boot_mem_map")
Signed-off-by: Thomas Bogendoerfer 
Signed-off-by: Paul Burton 
Cc: Ralf Baechle 
Cc: James Hogan 
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org

mips: avoid explicit UB in assignment of mips_io_port_base

2019-08-24T14:10:58+00:00

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

MIPS: Fix build with CONFIG_PROC_VMCORE=y

2019-08-23T17:02:49+00:00

Commit a94e4f24ec83 ("MIPS: init: Drop boot_mem_map") introduced a
reference to a non-existant "end" field in struct memblock_region.
Replace it with a sum of the base & size fields to fix builds with
CONFIG_PROC_VMCORE=y.

Reported-by: kbuild test robot 
Signed-off-by: Paul Burton

MIPS: init: Drop boot_mem_map

2019-08-23T14:42:40+00:00

boot_mem_map was introduced very early and cannot handle memory maps
with nid. Nowadays, memblock can exactly replace boot_mem_map.

Detect pfn info and setup resources with memblock maps.

Signed-off-by: Jiaxun Yang 
[paul.burton@mips.com: Fix size calculation in check_kernel_sections_mem]
Signed-off-by: Paul Burton 
Cc: linux-mips@vger.kernel.org
Cc: yasha.che3@gmail.com
Cc: aurelien@aurel32.net
Cc: sfr@canb.auug.org.au
Cc: fancer.lancer@gmail.com
Cc: matt.redfearn@mips.com
Cc: chenhc@lemote.com

mips: Manually call fdt_init_reserved_mem() method

2019-05-06T03:12:20+00:00

Since memblock-patchset was introduced the reserved-memory nodes are
supported being declared in dt-files. So these nodes are actually parsed
during the arch setup procedure when the early_init_fdt_scan_reserved_mem()
method is called. But due to the arch-specific boot mem_map container
utilization we need to manually call the fdt_init_reserved_mem() method
after all the available and reserved memory has been moved to memblock.
The first function call performed before bootmem_init() by the
early_init_fdt_scan_reserved_mem() routine fails due to the lack of any
memblock memory regions to allocate from at that stage.

Signed-off-by: Serge Semin 
Signed-off-by: Paul Burton 
Cc: Ralf Baechle 
Cc: James Hogan 
Cc: Mike Rapoport 
Cc: Andrew Morton 
Cc: Michal Hocko 
Cc: Greg Kroah-Hartman 
Cc: Thomas Bogendoerfer 
Cc: Huacai Chen 
Cc: Stefan Agner 
Cc: Stephen Rothwell 
Cc: Alexandre Belloni 
Cc: Juergen Gross 
Cc: Serge Semin 
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org

mips: Perform early low memory test

2019-05-03T22:26:10+00:00

memblock subsystem provides a method to optionally test the passed
memory region in case if it was requested via special kernel boot
argument. Lets add the function at the bottom of the arch_mem_init()
method. Testing at this point in the boot sequence should be safe since all
critical areas are now reserved and a minimum of allocations have been
done.

Reviewed-by: Matt Redfearn 
Signed-off-by: Serge Semin 
Signed-off-by: Paul Burton 
Cc: Ralf Baechle 
Cc: James Hogan 
Cc: Mike Rapoport 
Cc: Andrew Morton 
Cc: Michal Hocko 
Cc: Greg Kroah-Hartman 
Cc: Thomas Bogendoerfer 
Cc: Huacai Chen 
Cc: Stefan Agner 
Cc: Stephen Rothwell 
Cc: Alexandre Belloni 
Cc: Juergen Gross 
Cc: Serge Semin 
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org

mips: Dump memblock regions for debugging

2019-05-03T22:24:12+00:00

It is useful to have the whole memblock memory space printed to console
when basic memlock initializations are done. It can be performed by
ready-to-use method memblock_dump_all(), which prints the available
and reserved memory spaces if memblock=debug kernel parameter is
specified. Lets call it at the very end of arch_mem_init() function,
when all memblock memory and reserved regions are defined, but before
any serious allocation is performed.

Signed-off-by: Serge Semin 
Signed-off-by: Paul Burton 
Cc: Ralf Baechle 
Cc: James Hogan 
Cc: Mike Rapoport 
Cc: Andrew Morton 
Cc: Michal Hocko 
Cc: Greg Kroah-Hartman 
Cc: Thomas Bogendoerfer 
Cc: Huacai Chen 
Cc: Stefan Agner 
Cc: Stephen Rothwell 
Cc: Alexandre Belloni 
Cc: Juergen Gross 
Cc: Serge Semin 
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org

mips: Add reserve-nomap memory type support

2019-05-02T18:27:11+00:00

It might be necessary to prevent the virtual mapping creation for a
requested memory region. For instance there is a "no-map" property
indicating exactly this feature. In this case we need to not only
reserve the specified region by pretending it doesn't exist in the
memory space, but completely remove the range from system just by
removing it from memblock. The same way it's done in default
early_init_dt_reserve_memory_arch() method.

Signed-off-by: Serge Semin 
Signed-off-by: Paul Burton 
Cc: Ralf Baechle 
Cc: James Hogan 
Cc: Matt Redfearn 
Cc: Mike Rapoport 
Cc: Andrew Morton 
Cc: Michal Hocko 
Cc: Greg Kroah-Hartman 
Cc: Thomas Bogendoerfer 
Cc: Huacai Chen 
Cc: Stefan Agner 
Cc: Stephen Rothwell 
Cc: Alexandre Belloni 
Cc: Juergen Gross 
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org

mips: Use memblock to reserve the __nosave memory range

2019-05-02T18:24:34+00:00

Originally before legacy bootmem was removed, the memory for the range was
correctly reserved by reserve_bootmem_region(). But since memblock has been
selected for early memory allocation the function can be utilized only
after paging is fully initialized (as it is done by memblock_free_all()
function). So calling it from arch_mem_init() method is prone to errors,
and at this stage we need to reserve the memory in the memblock allocator.

Signed-off-by: Serge Semin 
Signed-off-by: Paul Burton 
Cc: Ralf Baechle 
Cc: James Hogan 
Cc: Matt Redfearn 
Cc: Mike Rapoport 
Cc: Andrew Morton 
Cc: Michal Hocko 
Cc: Greg Kroah-Hartman 
Cc: Thomas Bogendoerfer 
Cc: Huacai Chen 
Cc: Stefan Agner 
Cc: Stephen Rothwell 
Cc: Alexandre Belloni 
Cc: Juergen Gross 
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org