linux/arch/mips/mm, branch v3.1

MIPS: No branches in delay slots for huge pages in handle_tlbl

2011-09-21T15:54:07Z

For the case PM_DEFAULT_MASK == 0, we were placing a branch in the delay slot of another branch. This leads to undefined behavior. Signed-off-by: David Daney Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/2775/ Signed-off-by: Ralf Baechle

MIPS: tlbex: Fix build error in R3000 code.

2011-09-21T15:53:07Z

Only some GCC versions such as gcc 4.2 notice that the variable wr in build_r3000_tlb_modify_handler is used uninitialized. When using one of those GCCs the build will fail due to -Werror. GCC 4.6 does not warn about the uninitialized use of wr. This issue was introduced by 7211f4d7a3dcbe57c5d396c334dca525315dceb2 [MIPS: Close races in TLB modify handlers.] Reported-by: Ganesan Ramalingam Signed-off-by: Ralf Baechle

MIPS: Trivial style cleanups in mmap.c

2011-09-17T00:37:04Z

Fix checkpatch warnings. Rename arch_get_unmapped_area_foo() to arch_get_unmapped_area_common(). Make indentations and spacing more consistent. Add for likely/unlikely. Signed-off-by: Kevin Cernekee Cc: Jian Peng Cc: David Daney Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/2506/ Signed-off-by: Ralf Baechle

Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/upstream-linus

2011-07-26T21:17:28Z

* 'upstream' of git://git.linux-mips.org/pub/scm/upstream-linus: (31 commits) MIPS: Close races in TLB modify handlers. MIPS: Add uasm UASM_i_SRL_SAFE macro. MIPS: RB532: Use hex_to_bin() MIPS: Enable cpu_has_clo_clz for MIPS Technologies' platforms MIPS: PowerTV: Provide cpu-feature-overrides.h MIPS: Remove pointless return statement from empty void functions. MIPS: Limit fixrange_init() to the FIXMAP region MIPS: Install handlers for software IRQs MIPS: Move FIXADDR_TOP into spaces.h MIPS: Add SYNC after cacheflush MIPS: pfn_valid() is broken on low memory HIGHMEM systems MIPS: HIGHMEM DMA on noncoherent MIPS32 processors MIPS: topdown mmap support MIPS: Remove redundant addr_limit assignment on exec. MIPS: AR7: Replace __attribute__((__packed__)) with __packed MIPS: AR7: Remove 'space before tabs' in platform.c MIPS: Lantiq: Add missing clk_enable and clk_disable functions. MIPS: AR7: Fix trailing semicolon bug in clock.c MAINTAINERS: Update MIPS entry. MIPS: BCM63xx: Remove duplicate PERF_IRQSTAT_REG definition ...

MIPS: Close races in TLB modify handlers.

2011-07-26T05:47:47Z

Page table entries are made invalid by writing a zero into the the PTE slot in a page table. This creates a race condition with the TLB modify handlers when they are updating the PTE. CPU0 CPU1 Test for _PAGE_PRESENT . set to not _PAGE_PRESENT (zero) Set to _PAGE_VALID So now the page not present value (zero) is suddenly valid and user space programs have access to physical page zero. We close the race by putting the test for _PAGE_PRESENT and setting of _PAGE_VALID into an atomic LL/SC section. This requires more registers than just K0 and K1 in the handlers, so we need to save some registers to a save area and then restore them when we are done. The save area is an array of cacheline aligned structures that should not suffer cache line bouncing as they are CPU private. [ralf@linux-mips.org: Fix !defined(CONFIG_MIPS_PGD_C0_CONTEXT) build error.] Signed-off-by: David Daney To: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/2577/ Signed-off-by: Ralf Baechle

MIPS: Limit fixrange_init() to the FIXMAP region

2011-07-25T16:26:54Z

fixrange_init() allocates page tables for all addresses higher than FIXADDR_TOP. On processors that override the default FIXADDR_TOP address of 0xfffe_0000, this can consume up to 4 pages (1 page per 4MB) for pgd's that are never used. Signed-off-by: Kevin Cernekee Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/1980/ Signed-off-by: Ralf Baechle

MIPS: Add SYNC after cacheflush

2011-07-25T16:26:53Z

On processors with deep write buffers, it is likely that many cycles will pass between a CACHE instruction and the time the data actually gets written out to DRAM. Add a SYNC instruction to ensure that the buffers get emptied before the flush functions return. Actual problem seen in the wild: 1) dma_alloc_coherent() allocates cached memory 2) memset() is called to clear the new pages 3) dma_cache_wback_inv() is called to flush the zero data out to memory 4) dma_alloc_coherent() returns an uncached (kseg1) pointer to the freshly allocated pages 5) Caller writes data through the kseg1 pointer 6) Buffered writeback data finally gets flushed out to DRAM 7) Part of caller's data is inexplicably zeroed out This patch adds SYNC between steps 3 and 4, which fixed the problem. Signed-off-by: Kevin Cernekee Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: Signed-off-by: Ralf Baechle

MIPS: pfn_valid() is broken on low memory HIGHMEM systems

2011-07-25T16:26:52Z

pfn_valid() compares the PFN to max_mapnr: __pfn >= min_low_pfn && __pfn < max_mapnr; On HIGHMEM kernels, highend_pfn is used to set the value of max_mapnr. Unfortunately, highend_pfn is left at zero if the system does not actually have enough RAM to reach into the HIGHMEM range. This causes pfn_valid() to always return false, and when debug checks are enabled the kernel will fail catastrophically: Memory: 22432k/32768k available (2249k kernel code, 10336k reserved, 653k data, 1352k init, 0k highmem) NR_IRQS:128 kfree_debugcheck: out of range ptr 81c02900h. Kernel bug detected[#1]: Cpu 0 $ 0 : 00000000 10008400 00000034 00000000 $ 4 : 8003e160 802a0000 8003e160 00000000 $ 8 : 00000000 0000003e 00000747 00000747 ... On such a configuration, max_low_pfn should be used to set max_mapnr. This was seen on 2.6.34. Signed-off-by: Kevin Cernekee To: Ralf Baechle Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/1992/ Signed-off-by: Ralf Baechle

MIPS: HIGHMEM DMA on noncoherent MIPS32 processors

2011-07-25T16:26:52Z

[v4: Patch applies to linux-queue.git with kmap_atomic patches: https://patchwork.kernel.org/patch/189932/ https://patchwork.kernel.org/patch/194552/ https://patchwork.kernel.org/patch/189912/ ] The MIPS DMA coherency functions do not work properly (i.e. kernel oops) when HIGHMEM pages are passed in as arguments. Use kmap_atomic() to temporarily map high pages for cache maintenance operations. Tested on a 2.6.36-rc7 1GB HIGHMEM SMP no-alias system. Signed-off-by: Dezhong Diao Signed-off-by: Kevin Cernekee Cc: Dezhong Diao Cc: David Daney Cc: David VomLehn Cc: Sergei Shtylyov Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/1695/ Signed-off-by: Ralf Baechle

MIPS: topdown mmap support

2011-07-25T16:26:51Z

This patch introduced topdown mmap support in user process address space allocation policy. Recently, we ran some large applications that use mmap heavily and lead to OOM due to inflexible mmap allocation policy on MIPS32. Since most other major archs supported it for years, it is reasonable to follow the trend and reduce the pain of porting applications. Due to cache aliasing concern, arch_get_unmapped_area_topdown() and other helper functions are implemented in arch/mips/kernel/syscall.c. Signed-off-by: Jian Peng Cc: David Daney Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/2389/ Signed-off-by: Ralf Baechle