kernel.git/arch/arm/mm, branch linux-4.7.y

ARM: 8561/3: dma-mapping: Don't use outer_flush_range when the L2C is coherent

2016-08-20T16:10:57Z

commit f12708965069410691e47d1d216ec7ad1516bfd2 upstream. When a L2 cache controller is used in a system that provides hardware coherency, the entire outer cache operations are useless, and can be skipped. Moreover, on some systems, it is harmful as it causes deadlocks between the Marvell coherency mechanism, the Marvell PCIe controller and the Cortex-A9. In the current kernel implementation, the outer cache flush range operation is triggered by the dma_alloc function. This operation can be take place during runtime and in some circumstances may lead to the PCIe/PL310 deadlock on Armada 375/38x SoCs. This patch extends the __dma_clear_buffer() function to receive a boolean argument related to the coherency of the system. The same things is done for the calling functions. Reported-by: Nadav Haklai Signed-off-by: Gregory CLEMENT Signed-off-by: Russell King Signed-off-by: Greg Kroah-Hartman

lib/GCD.c: use binary GCD algorithm instead of Euclidean

2016-05-21T00:58:30Z

The binary GCD algorithm is based on the following facts: 1. If a and b are all evens, then gcd(a,b) = 2 * gcd(a/2, b/2) 2. If a is even and b is odd, then gcd(a,b) = gcd(a/2, b) 3. If a and b are all odds, then gcd(a,b) = gcd((a-b)/2, b) = gcd((a+b)/2, b) Even on x86 machines with reasonable division hardware, the binary algorithm runs about 25% faster (80% the execution time) than the division-based Euclidian algorithm. On platforms like Alpha and ARMv6 where division is a function call to emulation code, it's even more significant. There are two variants of the code here, depending on whether a fast __ffs (find least significant set bit) instruction is available. This allows the unpredictable branches in the bit-at-a-time shifting loop to be eliminated. If fast __ffs is not available, the "even/odd" GCD variant is used. I use the following code to benchmark: #include #include #include #include #include #include #define swap(a, b) \ do { \ a ^= b; \ b ^= a; \ a ^= b; \ } while (0) unsigned long gcd0(unsigned long a, unsigned long b) { unsigned long r; if (a < b) { swap(a, b); } if (b == 0) return a; while ((r = a % b) != 0) { a = b; b = r; } return b; } unsigned long gcd1(unsigned long a, unsigned long b) { unsigned long r = a | b; if (!a || !b) return r; b >>= __builtin_ctzl(b); for (;;) { a >>= __builtin_ctzl(a); if (a == b) return a << __builtin_ctzl(r); if (a < b) swap(a, b); a -= b; } } unsigned long gcd2(unsigned long a, unsigned long b) { unsigned long r = a | b; if (!a || !b) return r; r &= -r; while (!(b & r)) b >>= 1; for (;;) { while (!(a & r)) a >>= 1; if (a == b) return a; if (a < b) swap(a, b); a -= b; a >>= 1; if (a & r) a += b; a >>= 1; } } unsigned long gcd3(unsigned long a, unsigned long b) { unsigned long r = a | b; if (!a || !b) return r; b >>= __builtin_ctzl(b); if (b == 1) return r & -r; for (;;) { a >>= __builtin_ctzl(a); if (a == 1) return r & -r; if (a == b) return a << __builtin_ctzl(r); if (a < b) swap(a, b); a -= b; } } unsigned long gcd4(unsigned long a, unsigned long b) { unsigned long r = a | b; if (!a || !b) return r; r &= -r; while (!(b & r)) b >>= 1; if (b == r) return r; for (;;) { while (!(a & r)) a >>= 1; if (a == r) return r; if (a == b) return a; if (a < b) swap(a, b); a -= b; a >>= 1; if (a & r) a += b; a >>= 1; } } static unsigned long (*gcd_func[])(unsigned long a, unsigned long b) = { gcd0, gcd1, gcd2, gcd3, gcd4, }; #define TEST_ENTRIES (sizeof(gcd_func) / sizeof(gcd_func[0])) #if defined(__x86_64__) #define rdtscll(val) do { \ unsigned long __a,__d; \ __asm__ __volatile__("rdtsc" : "=a" (__a), "=d" (__d)); \ (val) = ((unsigned long long)__a) | (((unsigned long long)__d)<<32); \ } while(0) static unsigned long long benchmark_gcd_func(unsigned long (*gcd)(unsigned long, unsigned long), unsigned long a, unsigned long b, unsigned long *res) { unsigned long long start, end; unsigned long long ret; unsigned long gcd_res; rdtscll(start); gcd_res = gcd(a, b); rdtscll(end); if (end >= start) ret = end - start; else ret = ~0ULL - start + 1 + end; *res = gcd_res; return ret; } #else static inline struct timespec read_time(void) { struct timespec time; clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &time); return time; } static inline unsigned long long diff_time(struct timespec start, struct timespec end) { struct timespec temp; if ((end.tv_nsec - start.tv_nsec) < 0) { temp.tv_sec = end.tv_sec - start.tv_sec - 1; temp.tv_nsec = 1000000000ULL + end.tv_nsec - start.tv_nsec; } else { temp.tv_sec = end.tv_sec - start.tv_sec; temp.tv_nsec = end.tv_nsec - start.tv_nsec; } return temp.tv_sec * 1000000000ULL + temp.tv_nsec; } static unsigned long long benchmark_gcd_func(unsigned long (*gcd)(unsigned long, unsigned long), unsigned long a, unsigned long b, unsigned long *res) { struct timespec start, end; unsigned long gcd_res; start = read_time(); gcd_res = gcd(a, b); end = read_time(); *res = gcd_res; return diff_time(start, end); } #endif static inline unsigned long get_rand() { if (sizeof(long) == 8) return (unsigned long)rand() << 32 | rand(); else return rand(); } int main(int argc, char **argv) { unsigned int seed = time(0); int loops = 100; int repeats = 1000; unsigned long (*res)[TEST_ENTRIES]; unsigned long long elapsed[TEST_ENTRIES]; int i, j, k; for (;;) { int opt = getopt(argc, argv, "n:r:s:"); /* End condition always first */ if (opt == -1) break; switch (opt) { case 'n': loops = atoi(optarg); break; case 'r': repeats = atoi(optarg); break; case 's': seed = strtoul(optarg, NULL, 10); break; default: /* You won't actually get here. */ break; } } res = malloc(sizeof(unsigned long) * TEST_ENTRIES * loops); memset(elapsed, 0, sizeof(elapsed)); srand(seed); for (j = 0; j < loops; j++) { unsigned long a = get_rand(); /* Do we have args? */ unsigned long b = argc > optind ? strtoul(argv[optind], NULL, 10) : get_rand(); unsigned long long min_elapsed[TEST_ENTRIES]; for (k = 0; k < repeats; k++) { for (i = 0; i < TEST_ENTRIES; i++) { unsigned long long tmp = benchmark_gcd_func(gcd_func[i], a, b, &res[j][i]); if (k == 0 || min_elapsed[i] > tmp) min_elapsed[i] = tmp; } } for (i = 0; i < TEST_ENTRIES; i++) elapsed[i] += min_elapsed[i]; } for (i = 0; i < TEST_ENTRIES; i++) printf("gcd%d: elapsed %llu\n", i, elapsed[i]); k = 0; srand(seed); for (j = 0; j < loops; j++) { unsigned long a = get_rand(); unsigned long b = argc > optind ? strtoul(argv[optind], NULL, 10) : get_rand(); for (i = 1; i < TEST_ENTRIES; i++) { if (res[j][i] != res[j][0]) break; } if (i < TEST_ENTRIES) { if (k == 0) { k = 1; fprintf(stderr, "Error:\n"); } fprintf(stderr, "gcd(%lu, %lu): ", a, b); for (i = 0; i < TEST_ENTRIES; i++) fprintf(stderr, "%ld%s", res[j][i], i < TEST_ENTRIES - 1 ? ", " : "\n"); } } if (k == 0) fprintf(stderr, "PASS\n"); free(res); return 0; } Compiled with "-O2", on "VirtualBox 4.4.0-22-generic #38-Ubuntu x86_64" got: zhaoxiuzeng@zhaoxiuzeng-VirtualBox:~/develop$ ./gcd -r 500000 -n 10 gcd0: elapsed 10174 gcd1: elapsed 2120 gcd2: elapsed 2902 gcd3: elapsed 2039 gcd4: elapsed 2812 PASS zhaoxiuzeng@zhaoxiuzeng-VirtualBox:~/develop$ ./gcd -r 500000 -n 10 gcd0: elapsed 9309 gcd1: elapsed 2280 gcd2: elapsed 2822 gcd3: elapsed 2217 gcd4: elapsed 2710 PASS zhaoxiuzeng@zhaoxiuzeng-VirtualBox:~/develop$ ./gcd -r 500000 -n 10 gcd0: elapsed 9589 gcd1: elapsed 2098 gcd2: elapsed 2815 gcd3: elapsed 2030 gcd4: elapsed 2718 PASS zhaoxiuzeng@zhaoxiuzeng-VirtualBox:~/develop$ ./gcd -r 500000 -n 10 gcd0: elapsed 9914 gcd1: elapsed 2309 gcd2: elapsed 2779 gcd3: elapsed 2228 gcd4: elapsed 2709 PASS [akpm@linux-foundation.org: avoid #defining a CONFIG_ variable] Signed-off-by: Zhaoxiu Zeng Signed-off-by: George Spelvin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge branch 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm

2016-05-20T17:01:38Z

Pull ARM updates from Russell King: "Changes included in this pull request: - revert pxa2xx-flash back to using ioremap_cached() and switch memremap() to use arch_memremap_wb() - remove pci=firmware command line argument handling - remove unnecessary arm_dma_set_mask() implementation, the generic implementation will do for ARM - removal of the ARM kallsyms "hack" to work around mode switching veneers and vectors located below PAGE_OFFSET - tidy up build system output a little - add L2 cache power management DT bindings - remove duplicated local_irq_disable() in reboot paths - handle AMBA primecell devices better at registration time with PM domains (needed for Samsung SoCs) - ARM specific preparation to support Keystone II kexec" * 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: ARM: 8567/1: cache-uniphier: activate ways for secondary CPUs ARM: 8570/2: Documentation: devicetree: Add PL310 PM bindings ARM: 8569/1: pl2x0: Add OF control of cache power management ARM: 8568/1: reboot: remove duplicated local_irq_disable() ARM: 8566/1: drivers: amba: properly handle devices with power domains ARM: provide arm_has_idmap_alias() helper ARM: kexec: remove 512MB restriction on kexec crashdump ARM: provide improved virt_to_idmap() functionality ARM: kexec: fix crashkernel= handling ARM: 8557/1: specify install, zinstall, and uinstall as PHONY targets ARM: 8562/1: suppress "include/generated/mach-types.h is up to date." ARM: 8553/1: kallsyms: remove --page-offset command line option ARM: 8552/1: kallsyms: remove special lower address limit for CONFIG_ARM ARM: 8555/1: kallsyms: ignore ARM mode switching veneers ARM: 8548/1: dma-mapping: remove arm_dma_set_mask() ARM: 8554/1: kernel: pci: remove pci=firmware command line parameter handling ARM: memremap: implement arch_memremap_wb() memremap: add arch specific hook for MEMREMAP_WB mappings mtd: pxa2xx-flash: switch back from memremap to ioremap_cached ARM: reintroduce ioremap_cached() for creating cached I/O mappings

Merge branches 'amba', 'devel-stable', 'kexec-for-next' and 'misc' into for-linus

2016-05-19T09:31:35Z

iommu: of: enforce const-ness of struct iommu_ops

2016-05-09T13:33:29Z

As a set of driver-provided callbacks and static data, there is no compelling reason for struct iommu_ops to be mutable in core code, so enforce const-ness throughout. Acked-by: Thierry Reding Signed-off-by: Robin Murphy Acked-by: Will Deacon Signed-off-by: Joerg Roedel

Merge branch 'fixes' of git://git.armlinux.org.uk/~rmk/linux-arm

2016-05-07T15:27:35Z

Pull ARM fixes from Russell King: "These are a number of updates to fix a few problems found in the ARM nommu code over the last couple of years, caused mostly by changes on the mmu side" * 'fixes' of git://git.armlinux.org.uk/~rmk/linux-arm: ARM: 8573/1: domain: move {set,get}_domain under config guard ARM: 8572/1: nommu: change memory reserve for the vectors ARM: 8571/1: nommu: fix PMSAv7 setup

ARM: 8567/1: cache-uniphier: activate ways for secondary CPUs

2016-05-05T18:03:39Z

This outer cache allows to control active ways independently for each CPU, but currently nothing is done for secondary CPUs. In other words, all the ways are locked for secondary CPUs by default. This commit fixes it to fully bring out the performance of this outer cache. There would be two possible ways to achieve this: [1] Each CPU initializes active ways for itself. This can be done via the SSCLPDAWCR register. This is a banked register, so each CPU sees a different instance of the register for its own. [2] The master CPU initializes active ways for all the CPUs. This is available via SSCDAWCARMR(N) registers, where all instances of SSCLPDAWCR are mirrored. They are mapped at the address SSCDAWCARMR + 4 * N, where N is the CPU number. The outer cache frame work does not support a per-CPU init callback. So this commit adopts [2]; the master CPU iterates over possible CPUs setting up SSCDAWCARMR(N) registers. Signed-off-by: Masahiro Yamada Signed-off-by: Russell King

ARM: 8572/1: nommu: change memory reserve for the vectors

2016-05-05T18:03:02Z

Commit 19accfd3 (ARM: move vector stubs) moved the vector stubs in an additional page above the base vector one. This change wasn't taken into account by the nommu memreserve. This patch ensures that the kernel won't overwrite any vector stub on nommu. [changed the MPU side too] Signed-off-by: Jean-Philippe Brucker Signed-off-by: Vladimir Murzin Signed-off-by: Russell King

ARM: 8571/1: nommu: fix PMSAv7 setup

2016-05-05T18:03:01Z

Commit 1c2f87c (ARM: 8025/1: Get rid of meminfo) broke the support for MPU on ARMv7-R. This patch adapts the code inside CONFIG_ARM_MPU to use memblocks appropriately. MPU initialisation only uses the first memory region, and removes all subsequent ones. Because looping over all regions that need removal is inefficient, and memblock_remove already handles memory ranges, we can flatten the 'for_each_memblock' part. Signed-off-by: Jean-Philippe Brucker Signed-off-by: Vladimir Murzin Signed-off-by: Russell King

ARM: 8569/1: pl2x0: Add OF control of cache power management

2016-05-05T18:02:10Z

Add ability to override power management bits of 310 controllers (dynamic clock gating and standby mode) through OF entries. As the saved register is only applied when working on a supported controller, it is safe to save the settings. In order to maintain existing behavior, if the settings are not found in the DT, the corresponding feature will be enabled. Signed-off-by: Brad Mouring Signed-off-by: Russell King