kernel/linux.git/arch/arc/mm, branch linux-4.4.y

ARC: export clear_user_page() for modules

2021-09-22T09:41:27+00:00

[ Upstream commit 6b5ff0405e4190f23780362ea324b250bc495683 ] 0day bot reports a build error: ERROR: modpost: "clear_user_page" [drivers/media/v4l2-core/videobuf-dma-sg.ko] undefined! so export it in arch/arc/ to fix the build error. In most ARCHes, clear_user_page() is a macro. OTOH, in a few ARCHes it is a function and needs to be exported. PowerPC exported it in 2004. It looks like nds32 and nios2 still need to have it exported. Fixes: 4102b53392d63 ("ARC: [mm] Aliasing VIPT dcache support 2/4") Signed-off-by: Randy Dunlap Reported-by: kernel test robot Cc: Guenter Roeck Cc: linux-snps-arc@lists.infradead.org Signed-off-by: Vineet Gupta Signed-off-by: Sasha Levin

arc: fix type warnings in arc/mm/cache.c

2018-09-05T07:18:36+00:00

[ Upstream commit ec837d620c750c0d4996a907c8c4f7febe1bbeee ] Fix type warnings in arch/arc/mm/cache.c. ../arch/arc/mm/cache.c: In function 'flush_anon_page': ../arch/arc/mm/cache.c:1062:55: warning: passing argument 2 of '__flush_dcache_page' makes integer from pointer without a cast [-Wint-conversion] __flush_dcache_page((phys_addr_t)page_address(page), page_address(page)); ^~~~~~~~~~~~~~~~~~ ../arch/arc/mm/cache.c:1013:59: note: expected 'long unsigned int' but argument is of type 'void *' void __flush_dcache_page(phys_addr_t paddr, unsigned long vaddr) ~~~~~~~~~~~~~~^~~~~ Signed-off-by: Randy Dunlap Cc: Vineet Gupta Cc: linux-snps-arc@lists.infradead.org Cc: Elad Kanfi Cc: Leon Romanovsky Cc: Ofer Levi Signed-off-by: Vineet Gupta Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

ARC: Re-enable MMU upon Machine Check exception

2017-09-27T09:00:16+00:00

commit 1ee55a8f7f6b7ca4c0c59e0b4b4e3584a085c2d3 upstream. I recently came upon a scenario where I would get a double fault machine check exception tiriggered by a kernel module. However the ensuing crash stacktrace (ksym lookup) was not working correctly. Turns out that machine check auto-disables MMU while modules are allocated in kernel vaddr spapce. This patch re-enables the MMU before start printing the stacktrace making stacktracing of modules work upon a fatal exception. Signed-off-by: Jose Abreu Reviewed-by: Alexey Brodkin Signed-off-by: Vineet Gupta [vgupta: moved code into low level handler to avoid in 2 places] Signed-off-by: Greg Kroah-Hartman

ARCv2: PAE40: Explicitly set MSB counterpart of SLC region ops addresses

2017-08-30T08:19:22+00:00

commit 7d79cee2c6540ea64dd917a14e2fd63d4ac3d3c0 upstream. It is necessary to explicitly set both SLC_AUX_RGN_START1 and SLC_AUX_RGN_END1 which hold MSB bits of the physical address correspondingly of region start and end otherwise SLC region operation is executed in unpredictable manner Without this patch, SLC flushes on HSDK (IOC disabled) were taking seconds. Reported-by: Vladimir Kondratiev Signed-off-by: Alexey Brodkin Signed-off-by: Vineet Gupta [vgupta: PAR40 regs only written if PAE40 exist] Signed-off-by: Greg Kroah-Hartman

mm: larger stack guard gap, between vmas

2017-06-26T05:13:11+00:00

commit 1be7107fbe18eed3e319a6c3e83c78254b693acb upstream. Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov Original-patch-by: Michal Hocko Signed-off-by: Hugh Dickins Acked-by: Michal Hocko Tested-by: Helge Deller # parisc Signed-off-by: Linus Torvalds [wt: backport to 4.11: adjust context] [wt: backport to 4.9: adjust context ; kernel doc was not in admin-guide] [wt: backport to 4.4: adjust context ; drop ppc hugetlb_radix changes] Signed-off-by: Willy Tarreau [gkh: minor build fixes for 4.4] Signed-off-by: Greg Kroah-Hartman

ARC: mm: arc700: Don't assume 2 colours for aliasing VIPT dcache

2017-01-09T07:07:48+00:00

commit 08fe007968b2b45e831daf74899f79a54d73f773 upstream. An ARC700 customer reported linux boot crashes when upgrading to bigger L1 dcache (64K from 32K). Turns out they had an aliasing VIPT config and current code only assumed 2 colours, while theirs had 4. So default to 4 colours and complain if there are fewer. Ideally this needs to be a Kconfig option, but heck that's too much of hassle for a single user. Signed-off-by: Vineet Gupta Signed-off-by: Greg Kroah-Hartman

ARC: Elide redundant setup of DMA callbacks

2016-09-07T06:32:42+00:00

commit 45c3b08a117e2232fc8d7b9e849ead36386f4f96 upstream. For resources shared by all cores such as SLC and IOC, only the master core needs to do any setups / enabling / disabling etc. Signed-off-by: Vineet Gupta Signed-off-by: Greg Kroah-Hartman

ARC: mm: HIGHMEM: Fix section mismatch splat

2015-12-21T06:40:40+00:00

| WARNING: vmlinux.o(.text+0xd6c2): Section mismatch in reference from the function alloc_kmap_pgtable() to the function | .init.text:__alloc_bootmem_low() The function alloc_kmap_pgtable() references the function __init __alloc_bootmem_low(). This is often because alloc_kmap_pgtable lacks a __init annotation or the annotation of __alloc_bootmem_low is wrong. Signed-off-by: Vineet Gupta

ARC: [plat-sim] unbork non default CONFIG_LINUX_LINK_BASE

2015-12-17T05:36:43+00:00

HIGHMEM support bumped the default memory size for nsim platform to 1G. Thus total memory ended at the very edge of start of peripherals address space. With linux link base shifted, memory started bleeding into peripheral space which caused early boot bad_page spew ! Fixes: 29e332261d2 ("ARC: mm: HIGHMEM: populate high memory from DT") Reported-by: Anton Kolesov Signed-off-by: Vineet Gupta

ARC: comments update

2015-11-16T06:30:16+00:00

Signed-off-by: Vineet Gupta