Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755270AbaDNNuR (ORCPT ); Mon, 14 Apr 2014 09:50:17 -0400 Received: from mail-qg0-f48.google.com ([209.85.192.48]:54671 "EHLO mail-qg0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754815AbaDNNuM (ORCPT ); Mon, 14 Apr 2014 09:50:12 -0400 Date: Mon, 14 Apr 2014 09:50:08 -0400 (EDT) From: Nicolas Pitre To: Liu hua cc: Russell King - ARM Linux , Will Deacon , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, wangnan0@huawei.com, peifeiyue@huawei.com, liusdu@126.com, m.szyprowski@samsung.com Subject: Re: [PATCH v2 2/2] ARM : change fixmap mapping region to support 32 CPUs In-Reply-To: <534BD488.3020606@huawei.com> Message-ID: References: <1397203252-22977-1-git-send-email-sdu.liu@huawei.com> <1397203252-22977-3-git-send-email-sdu.liu@huawei.com> <534A9031.5030006@huawei.com> <534BD488.3020606@huawei.com> User-Agent: Alpine 2.11 (LFD 23 2013-08-11) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 14 Apr 2014, Liu hua wrote: > Yes, it seems that FIX_KMAP_BEGIN and FIX_KMAP_END are not as important for > ARM than that for other architectures (MIPS PowerPC x86), whose FIX_KMAP_BEGIN > is not 0. I will reminder this in my patch. Anyone who need them can get > imformantion there. > > > Now the new patchs are following. Maybe I sould resend the patch series > with a new tag. If It is time to do that. Can I add this information > "Reviewed-by: Nicolas Pitre " ? > > Thanks, > Liu Hua. > > -----------------patch 1------------------------- > > Subject: [PATCH 1/2] ARM : fixmap : remove FIX_KMAP_BEGIN and FIX_KMAP_END > > It seems that these two variables are not used by non > architecture specific code. And on ARM FIX_KMAP_BEGIN > equals zero; FIX_KMAP_END is totally not used by the > kernel. > > This patch removes these two variables. The code will > become clear when I introduce a bugfix on fixmap mapping s/clear/clearer/ > region. > > Signed-off-by: Liu Hua > --- > arch/arm/include/asm/fixmap.h | 12 ++++++++---- > arch/arm/mm/highmem.c | 6 +++--- > 2 files changed, 11 insertions(+), 7 deletions(-) > > diff --git a/arch/arm/include/asm/fixmap.h b/arch/arm/include/asm/fixmap.h > index bbae919..8675bb9 100644 > --- a/arch/arm/include/asm/fixmap.h > +++ b/arch/arm/include/asm/fixmap.h > @@ -17,9 +17,13 @@ > #define FIXADDR_TOP 0xfffe0000UL > #define FIXADDR_SIZE (FIXADDR_TOP - FIXADDR_START) > > -#define FIX_KMAP_BEGIN 0 > -#define FIX_KMAP_END (FIXADDR_SIZE >> PAGE_SHIFT) > - > +/* Notice : FIX_KMAP_END and FIX_KMAP_BEGIN are removed. > + * > + * Instead, using FIX_KMAP_NR_PTES to tell the pte number > + * belonged to fixmap mapping region. > + * > + */ Please move this comment to the commit log instead. This is not important enough to occupy that much space in the code. > +#define FIX_KMAP_NR_PTES (FIXADDR_SIZE >> PAGE_SHIFT) > #define __fix_to_virt(x) (FIXADDR_START + ((x) << PAGE_SHIFT)) > #define __virt_to_fix(x) (((x) - FIXADDR_START) >> PAGE_SHIFT) > > @@ -27,7 +31,7 @@ extern void __this_fixmap_does_not_exist(void); > > static inline unsigned long fix_to_virt(const unsigned int idx) > { > - if (idx >= FIX_KMAP_END) > + if (idx >= FIX_KMAP_NR_PTES) > __this_fixmap_does_not_exist(); > return __fix_to_virt(idx); > } > diff --git a/arch/arm/mm/highmem.c b/arch/arm/mm/highmem.c > index 21b9e1b..e05e8ad 100644 > --- a/arch/arm/mm/highmem.c > +++ b/arch/arm/mm/highmem.c > @@ -63,7 +63,7 @@ void *kmap_atomic(struct page *page) > type = kmap_atomic_idx_push(); > > idx = type + KM_TYPE_NR * smp_processor_id(); > - vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); > + vaddr = __fix_to_virt(idx); > #ifdef CONFIG_DEBUG_HIGHMEM > /* > * With debugging enabled, kunmap_atomic forces that entry to 0. > @@ -94,7 +94,7 @@ void __kunmap_atomic(void *kvaddr) > if (cache_is_vivt()) > __cpuc_flush_dcache_area((void *)vaddr, PAGE_SIZE); > #ifdef CONFIG_DEBUG_HIGHMEM > - BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx)); > + BUG_ON(vaddr != __fix_to_virt(idx)); > set_top_pte(vaddr, __pte(0)); > #else > (void) idx; /* to kill a warning */ > @@ -117,7 +117,7 @@ void *kmap_atomic_pfn(unsigned long pfn) > > type = kmap_atomic_idx_push(); > idx = type + KM_TYPE_NR * smp_processor_id(); > - vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); > + vaddr = __fix_to_virt(idx); > #ifdef CONFIG_DEBUG_HIGHMEM > BUG_ON(!pte_none(get_top_pte(vaddr))); > #endif > -- > 1.9.0 With the above details fixed you may add: Reviewed-by: Nicolas Pitre > -----------------patch 2------------------------- > > > > Subject: [PATCH 2/2] ARM : change fixmap mapping region to support 32 CPUs > > In 32-bit ARM systems, the fixmap mapping region can support > no more than 14 CPUs(total: 896k; one CPU: 64K). And we can > configure NR_CPUS up to 32. So there is a mismatch. > > This patch moves fixmapping region downwards to region > 0xffc00000-0xffe00000 . Then the fixmap mapping region can > support up to 32 CPUs > > Signed-off-by: Liu Hua > --- > Documentation/arm/memory.txt | 2 +- > arch/arm/include/asm/fixmap.h | 16 ++-------------- > arch/arm/include/asm/highmem.h | 1 + > arch/arm/mm/highmem.c | 27 +++++++++++++++++++++------ > arch/arm/mm/mmu.c | 4 ++++ > 5 files changed, 29 insertions(+), 21 deletions(-) > > diff --git a/Documentation/arm/memory.txt b/Documentation/arm/memory.txt > index d74e8a5..256c5e0 100644 > --- a/Documentation/arm/memory.txt > +++ b/Documentation/arm/memory.txt > @@ -41,7 +41,7 @@ fffe8000 fffeffff DTCM mapping area for platforms with > fffe0000 fffe7fff ITCM mapping area for platforms with > ITCM mounted inside the CPU. > > -fff00000 fffdffff Fixmap mapping region. Addresses provided > +fffc0000 ffdfffff Fixmap mapping region. Addresses provided > by fix_to_virt() will be located here. > > fee00000 feffffff Mapping of PCI I/O space. This is a static > diff --git a/arch/arm/include/asm/fixmap.h b/arch/arm/include/asm/fixmap.h > index 8675bb9..fb8a5a7 100644 > --- a/arch/arm/include/asm/fixmap.h > +++ b/arch/arm/include/asm/fixmap.h > @@ -1,20 +1,8 @@ > #ifndef _ASM_FIXMAP_H > #define _ASM_FIXMAP_H > > -/* > - * Nothing too fancy for now. > - * > - * On ARM we already have well known fixed virtual addresses imposed by > - * the architecture such as the vector page which is located at 0xffff0000, > - * therefore a second level page table is already allocated covering > - * 0xfff00000 upwards. > - * > - * The cache flushing code in proc-xscale.S uses the virtual area between > - * 0xfffe0000 and 0xfffeffff. > - */ > - > -#define FIXADDR_START 0xfff00000UL > -#define FIXADDR_TOP 0xfffe0000UL > +#define FIXADDR_START 0xffc00000UL > +#define FIXADDR_TOP 0xffe00000UL > #define FIXADDR_SIZE (FIXADDR_TOP - FIXADDR_START) > > /* Notice : FIX_KMAP_END and FIX_KMAP_BEGIN are removed. > diff --git a/arch/arm/include/asm/highmem.h b/arch/arm/include/asm/highmem.h > index 91b99ab..5355795 100644 > --- a/arch/arm/include/asm/highmem.h > +++ b/arch/arm/include/asm/highmem.h > @@ -18,6 +18,7 @@ > } while (0) > > extern pte_t *pkmap_page_table; > +extern pte_t *fixmap_page_table; > > extern void *kmap_high(struct page *page); > extern void kunmap_high(struct page *page); > diff --git a/arch/arm/mm/highmem.c b/arch/arm/mm/highmem.c > index e05e8ad..45aeaac 100644 > --- a/arch/arm/mm/highmem.c > +++ b/arch/arm/mm/highmem.c > @@ -18,6 +18,21 @@ > #include > #include "mm.h" > > +pte_t *fixmap_page_table; > + > +static inline void set_fixmap_pte(int idx, pte_t pte) > +{ > + unsigned long vaddr = __fix_to_virt(idx); > + set_pte_ext(fixmap_page_table + idx, pte, 0); > + local_flush_tlb_kernel_page(vaddr); > +} > + > +static inline pte_t get_fixmap_pte(unsigned long vaddr) > +{ > + unsigned long idx = __virt_to_fix(vaddr); > + return *(fixmap_page_table + idx); > +} > + > void *kmap(struct page *page) > { > might_sleep(); > @@ -69,14 +84,14 @@ void *kmap_atomic(struct page *page) > * With debugging enabled, kunmap_atomic forces that entry to 0. > * Make sure it was indeed properly unmapped. > */ > - BUG_ON(!pte_none(get_top_pte(vaddr))); > + BUG_ON(!pte_none(*(fixmap_page_table + idx))); > #endif > /* > * When debugging is off, kunmap_atomic leaves the previous mapping > * in place, so the contained TLB flush ensures the TLB is updated > * with the new mapping. > */ > - set_top_pte(vaddr, mk_pte(page, kmap_prot)); > + set_fixmap_pte(idx, mk_pte(page, kmap_prot)); > > return (void *)vaddr; > } > @@ -95,7 +110,7 @@ void __kunmap_atomic(void *kvaddr) > __cpuc_flush_dcache_area((void *)vaddr, PAGE_SIZE); > #ifdef CONFIG_DEBUG_HIGHMEM > BUG_ON(vaddr != __fix_to_virt(idx)); > - set_top_pte(vaddr, __pte(0)); > + set_fixmap_pte(idx, __pte(0)); > #else > (void) idx; /* to kill a warning */ > #endif > @@ -119,9 +134,9 @@ void *kmap_atomic_pfn(unsigned long pfn) > idx = type + KM_TYPE_NR * smp_processor_id(); > vaddr = __fix_to_virt(idx); > #ifdef CONFIG_DEBUG_HIGHMEM > - BUG_ON(!pte_none(get_top_pte(vaddr))); > + BUG_ON(!pte_none(*(fixmap_page_table + idx))); > #endif > - set_top_pte(vaddr, pfn_pte(pfn, kmap_prot)); > + set_fixmap_pte(idx, pfn_pte(pfn, kmap_prot)); > > return (void *)vaddr; > } > @@ -133,5 +148,5 @@ struct page *kmap_atomic_to_page(const void *ptr) > if (vaddr < FIXADDR_START) > return virt_to_page(ptr); > > - return pte_page(get_top_pte(vaddr)); > + return pte_page(get_fixmap_pte(vaddr)); > } > diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c > index b68c6b2..09c0a16 100644 > --- a/arch/arm/mm/mmu.c > +++ b/arch/arm/mm/mmu.c > @@ -35,6 +35,7 @@ > #include > #include > #include > +#include > > #include "mm.h" > #include "tcm.h" > @@ -1359,6 +1360,9 @@ static void __init kmap_init(void) > #ifdef CONFIG_HIGHMEM > pkmap_page_table = early_pte_alloc(pmd_off_k(PKMAP_BASE), > PKMAP_BASE, _PAGE_KERNEL_TABLE); > + > + fixmap_page_table = early_pte_alloc(pmd_off_k(FIXADDR_START), > + FIXADDR_START, _PAGE_KERNEL_TABLE); > #endif > } > > -- > 1.9.0 Reviewed-by: Nicolas Pitre > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/