Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754311AbaDNMcT (ORCPT ); Mon, 14 Apr 2014 08:32:19 -0400 Received: from szxga01-in.huawei.com ([119.145.14.64]:5425 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754064AbaDNMcR (ORCPT ); Mon, 14 Apr 2014 08:32:17 -0400 Message-ID: <534BD488.3020606@huawei.com> Date: Mon, 14 Apr 2014 20:28:56 +0800 From: Liu hua User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:24.0) Gecko/20100101 Thunderbird/24.0.1 MIME-Version: 1.0 To: Nicolas Pitre CC: Russell King - ARM Linux , Will Deacon , , , , , , Subject: Re: [PATCH v2 2/2] ARM : change fixmap mapping region to support 32 CPUs 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> In-Reply-To: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit X-Originating-IP: [10.111.58.238] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 于 2014/4/14 1:34, Nicolas Pitre 写道: > On Sun, 13 Apr 2014, Liu hua wrote: > >> Hi Nicolas. >> >> Sure, your suggestion made my patch looks better. How about that : >> >> Thanks, >> Liu Hua > > There is something else that bothers me. > >> + unsigned long idx = __virt_to_fix(vaddr); >> + idx -= FIX_KMAP_BEGIN; >> + return *(fixmap_page_table + idx); > > FIX_KMAP_BEGIN represents the starting point for mapping fixmap indices > to page table entries. So here you should _add_ the > FIX_KMAP_BEGIN offset to the page table index not substract it. > Currently FIX_KMAP_BEGIN is defined to 0 but still. > >> +} >> + >> #ifdef CONFIG_DEBUG_HIGHMEM >> - BUG_ON(!pte_none(get_top_pte(vaddr))); >> + BUG_ON(!pte_none(*(fixmap_page_table + idx))); > > Ditto here. > > In fact, this FIX_KMAP_BEGIN is only creating more confusing code for > nothing as we define it to 0 anyway, and it is not used by non > architecture specific code. So I'd suggest you create a patch to be > applied before this one that simply gets rid of FIX_KMAP_BEGIN and > FIX_KMAP_END altogether. We could reintroduce them back if ever they're > needed. > > > Nicolas > Hi Nicolas, 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 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. + * + */ +#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 -----------------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 -- 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/