From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (ozlabs.org [IPv6:2401:3900:2:1::2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id D45D31A0242 for ; Mon, 13 Oct 2014 18:14:37 +1100 (EST) Date: Mon, 13 Oct 2014 18:14:36 +1100 From: Anton Blanchard To: Scott Wood , Benjamin Herrenschmidt , Shaohui Xie , Michael Ellerman Subject: Re: [PATCH 1/4] powerpc: Dynamic DMA zone limits Message-ID: <20141013181436.300988c8@kryten> In-Reply-To: <1407541245-27617-1-git-send-email-scottwood@freescale.com> References: <1407541245-27617-1-git-send-email-scottwood@freescale.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Cc: linuxppc-dev@lists.ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hi Scott, > 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. This patch breaks my POWER8 box: ipr 0001:08:00.0: Using 64-bit DMA iommu bypass ipr 0001:08:00.0: dma_direct_alloc_coherent: No suitable zone for pfn 0x10000 ipr 0001:08:00.0: Couldn't allocate enough memory for device driver! ipr: probe of 0001:08:00.0 failed with error -12 ipr isn't setting a coherent mask, but we shouldn't care on these boxes. Could we ignore the coherent mask or copy the dma mask to it? Anton -- > 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 80b94b0..56dc47a 100644 > --- a/arch/powerpc/Kconfig > +++ b/arch/powerpc/Kconfig > @@ -286,6 +286,10 @@ 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 d98c1ec..6d74167 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 ee78f6e..dfd99ef 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 e0f7a18..3b23e17 100644 > --- a/arch/powerpc/mm/mem.c > +++ b/arch/powerpc/mm/mem.c > @@ -261,6 +261,54 @@ 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. */ > @@ -268,7 +316,7 @@ 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); @@ -290,13 +338,16 @@ 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();