From 1c98025c6c95bc057a25e2c6596de23288c68160 Mon Sep 17 00:00:00 2001 From: Scott Wood Date: Fri, 8 Aug 2014 18:40:42 -0500 Subject: [PATCH] powerpc: Dynamic DMA zone limits Platform code can call limit_zone_pfn() to set appropriate limits for ZONE_DMA and ZONE_DMA32, and dma_direct_alloc_coherent() will select a suitable zone based on a device's mask and the pfn limits that platform code has configured. Signed-off-by: Scott Wood Cc: Shaohui Xie --- arch/powerpc/Kconfig | 4 ++ arch/powerpc/include/asm/pgtable.h | 3 ++ arch/powerpc/kernel/dma.c | 20 ++++++++++ arch/powerpc/mm/mem.c | 61 +++++++++++++++++++++++++++--- 4 files changed, 83 insertions(+), 5 deletions(-) diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index bd6dd6ed3a9f..d003409b5f98 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -285,6 +285,10 @@ config PPC_EMULATE_SSTEP bool default y if KPROBES || UPROBES || XMON || HAVE_HW_BREAKPOINT +config ZONE_DMA32 + bool + default y if PPC64 + source "init/Kconfig" source "kernel/Kconfig.freezer" diff --git a/arch/powerpc/include/asm/pgtable.h b/arch/powerpc/include/asm/pgtable.h index d98c1ecc3266..6d74167bb6bf 100644 --- a/arch/powerpc/include/asm/pgtable.h +++ b/arch/powerpc/include/asm/pgtable.h @@ -4,6 +4,7 @@ #ifndef __ASSEMBLY__ #include +#include #include /* For TASK_SIZE */ #include #include @@ -281,6 +282,8 @@ extern unsigned long empty_zero_page[]; extern pgd_t swapper_pg_dir[]; +void limit_zone_pfn(enum zone_type zone, unsigned long max_pfn); +int dma_pfn_limit_to_zone(u64 pfn_limit); extern void paging_init(void); /* diff --git a/arch/powerpc/kernel/dma.c b/arch/powerpc/kernel/dma.c index ee78f6e49d64..dfd99ef8c63d 100644 --- a/arch/powerpc/kernel/dma.c +++ b/arch/powerpc/kernel/dma.c @@ -40,6 +40,26 @@ void *dma_direct_alloc_coherent(struct device *dev, size_t size, #else struct page *page; int node = dev_to_node(dev); + u64 pfn = (dev->coherent_dma_mask >> PAGE_SHIFT) + 1; + int zone; + + zone = dma_pfn_limit_to_zone(pfn); + if (zone < 0) { + dev_err(dev, "%s: No suitable zone for pfn %#llx\n", + __func__, pfn); + return NULL; + } + + switch (zone) { + case ZONE_DMA: + flag |= GFP_DMA; + break; +#ifdef CONFIG_ZONE_DMA32 + case ZONE_DMA32: + flag |= GFP_DMA32; + break; +#endif + }; /* ignore region specifiers */ flag &= ~(__GFP_HIGHMEM); diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c index 2c8e90f5789e..687e7f7f7751 100644 --- a/arch/powerpc/mm/mem.c +++ b/arch/powerpc/mm/mem.c @@ -260,6 +260,54 @@ static int __init mark_nonram_nosave(void) return 0; } +static bool zone_limits_final; + +static unsigned long max_zone_pfns[MAX_NR_ZONES] = { + [0 ... MAX_NR_ZONES - 1] = ~0UL +}; + +/* + * Restrict the specified zone and all more restrictive zones + * to be below the specified pfn. May not be called after + * paging_init(). + */ +void __init limit_zone_pfn(enum zone_type zone, unsigned long pfn_limit) +{ + int i; + + if (WARN_ON(zone_limits_final)) + return; + + for (i = zone; i >= 0; i--) { + if (max_zone_pfns[i] > pfn_limit) + max_zone_pfns[i] = pfn_limit; + } +} + +/* + * Find the least restrictive zone that is entirely below the + * specified pfn limit. Returns < 0 if no suitable zone is found. + * + * pfn_limit must be u64 because it can exceed 32 bits even on 32-bit + * systems -- the DMA limit can be higher than any possible real pfn. + */ +int dma_pfn_limit_to_zone(u64 pfn_limit) +{ + enum zone_type top_zone = ZONE_NORMAL; + int i; + +#ifdef CONFIG_HIGHMEM + top_zone = ZONE_HIGHMEM; +#endif + + for (i = top_zone; i >= 0; i--) { + if (max_zone_pfns[i] <= pfn_limit) + return i; + } + + return -EPERM; +} + /* * paging_init() sets up the page tables - in fact we've already done this. */ @@ -267,7 +315,7 @@ void __init paging_init(void) { unsigned long long total_ram = memblock_phys_mem_size(); phys_addr_t top_of_ram = memblock_end_of_DRAM(); - unsigned long max_zone_pfns[MAX_NR_ZONES]; + enum zone_type top_zone; #ifdef CONFIG_PPC32 unsigned long v = __fix_to_virt(__end_of_fixed_addresses - 1); @@ -289,13 +337,16 @@ void __init paging_init(void) (unsigned long long)top_of_ram, total_ram); printk(KERN_DEBUG "Memory hole size: %ldMB\n", (long int)((top_of_ram - total_ram) >> 20)); - memset(max_zone_pfns, 0, sizeof(max_zone_pfns)); + #ifdef CONFIG_HIGHMEM - max_zone_pfns[ZONE_DMA] = lowmem_end_addr >> PAGE_SHIFT; - max_zone_pfns[ZONE_HIGHMEM] = top_of_ram >> PAGE_SHIFT; + top_zone = ZONE_HIGHMEM; + limit_zone_pfn(ZONE_NORMAL, lowmem_end_addr >> PAGE_SHIFT); #else - max_zone_pfns[ZONE_DMA] = top_of_ram >> PAGE_SHIFT; + top_zone = ZONE_NORMAL; #endif + + limit_zone_pfn(top_zone, top_of_ram >> PAGE_SHIFT); + zone_limits_final = true; free_area_init_nodes(max_zone_pfns); mark_nonram_nosave(); -- 2.20.1