linux/arch/mips/kernel/setup.c, branch v4.9

MIPS: Fix max_low_pfn with disabled highmem

2016-11-04T00:45:22Z

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

2016-09-29T16:59:49Z

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

2016-09-13T12:13:26Z

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

2016-08-02T12:00:16Z

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

MIPS: Octeon: detect and fix byte swapped initramfs

2016-05-13T13:30:25Z

Octeon machines support running in little endian mode. U-Boot usually runs in big endian-mode. Therefore the initramfs is loaded in big endian mode, and the kernel later tries to access it in little endian mode. This patch fixes that by detecting byte swapped initramfs using either the CPIO header or the header from standard compression methods, and byte swaps it if needed. It first checks that the header doesn't match in the native endianness to avoid false detections. It uses the kernel decompress library so that we don't have to maintain the list of magics if some decompression methods are added to the kernel. Signed-off-by: Aurelien Jarno Acked-by: David Daney Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13219/ Signed-off-by: Ralf Baechle

MIPS: Add support for extending builtin cmdline

2016-05-13T12:02:21Z

Allow the builtin command line to be extended by what the bootloader passes in. For example, the bootloader can pass specific arguments depending on the boot mode, and these should override the defaults in the builtin cmdline. The default MIPS_CMDLINE_FROM_BOOTLOADER option prepends the bootloader's cmdline to the builtin cmdline so is not suitable for this purpose. Signed-off-by: Rabin Vincent Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13181/ Signed-off-by: Ralf Baechle

MIPS: Don't add leading spacing to command lines

2016-05-13T12:02:20Z

The leading spaces don't affect functionality but are unnecessary. Signed-off-by: Rabin Vincent Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13180/ Signed-off-by: Ralf Baechle

MIPS: make PCI_DMA_BUS_IS_PHYS=1 constant

2016-05-13T12:02:17Z

No one of supported MIPS machines has an IOMMU unit, so we can safely define PCI_DMA_BUS_IS_PHYS = 1. Also remove iommu flag from the pci controller structure, since it is useless. Signed-off-by: Sergey Ryazanov Cc: Linux MIPS Patchwork: https://patchwork.linux-mips.org/patch/7604/ Signed-off-by: Ralf Baechle

MIPS: KASLR: Print relocation Information on boot

2016-05-13T12:02:04Z

When debugging a relocated kernel, the addresses of the relocated symbols and the offset applied is essential information. If the kernel is compiled with debugging information, then print this information during bootup using the same function as the panic notifier. [ralf@linux-mips.org: Fixed spelling mistake pointed out by Sergei Shtylyov .] Signed-off-by: Matt Redfearn Cc: Aaro Koskinen Cc: Masahiro Yamada Cc: Alexander Sverdlin Cc: Jaedon Shin Cc: Jonas Gorski Cc: Paul Burton Cc: linux-mips@linux-mips.org Cc: kernel-hardening@lists.openwall.com Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/12989/ Signed-off-by: Ralf Baechle

MIPS: bootmem: When relocatable, free memory below kernel

2016-05-13T12:02:03Z

The kernel reserves all memory before the _end symbol as bootmem, however, once the kernel can be relocated elsewhere in memory this may result in a large amount of wasted memory. The assumption is that the memory between the link and relocated address of the kernel may be released back to the available memory pool. Memory statistics for a Malta with the kernel relocating by 16Mb, without the patch: Memory: 105952K/131072K available (4604K kernel code, 242K rwdata, 892K rodata, 1280K init, 183K bss, 25120K reserved, 0K cma-reserved) And with the patch: Memory: 122336K/131072K available (4604K kernel code, 242K rwdata, 892K rodata, 1280K init, 183K bss, 8736K reserved, 0K cma-reserved) The 16Mb offset is removed from the reserved region and added back to the available region. Signed-off-by: Matt Redfearn Cc: Aaro Koskinen Cc: Masahiro Yamada Cc: Alexander Sverdlin Cc: Jaedon Shin Cc: James Hogan Cc: Jonas Gorski Cc: Paul Burton Cc: linux-mips@linux-mips.org Cc: kernel-hardening@lists.openwall.com Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/12986/ Signed-off-by: Ralf Baechle