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Tue, 22 Oct 2019 09:11:09 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=c-s.fr; s=mail; t=1571728269; bh=kOGepsk5Ck4NL5FoHfVezc4/5OGKldi3JIwfABjXAjk=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=Ap4PZJPzPg5e764D9ApTCr8XIOyguzsvgMwq5AWR4E0/zh0xnRHlQQ+Eo1OlE7aTP ZixHcnTE7rBBIzhFUJshZizJQ+smXIHrl6Gc6+NAMSi/5KfWtkWR1KD31Zq3+rbJQP +WISNUI41CxdVRlDUOc/jgNhGI81GLU/ouuiJevE= Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 9F5758B916; Tue, 22 Oct 2019 09:11:10 +0200 (CEST) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id pUnm5Uq24Z86; Tue, 22 Oct 2019 09:11:10 +0200 (CEST) Received: from po16098vm.idsi0.si.c-s.fr (unknown [192.168.4.90]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 4B99C8B752; Tue, 22 Oct 2019 09:11:08 +0200 (CEST) Subject: Re: [PATCH V7] mm/debug: Add tests validating architecture page table helpers To: Anshuman Khandual , linux-mm@kvack.org References: <1571625739-29943-1-git-send-email-anshuman.khandual@arm.com> <1571625739-29943-2-git-send-email-anshuman.khandual@arm.com> From: Christophe Leroy Message-ID: <535564eb-65ea-69ab-977d-0038a9e4f785@c-s.fr> Date: Tue, 22 Oct 2019 07:11:07 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <1571625739-29943-2-git-send-email-anshuman.khandual@arm.com> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191022_001123_305330_CD6CD741 X-CRM114-Status: GOOD ( 31.19 ) X-BeenThere: linux-snps-arc@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on Synopsys ARC Processors List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , linux-ia64@vger.kernel.org, linux-sh@vger.kernel.org, Peter Zijlstra , James Hogan , Heiko Carstens , Michal Hocko , Dave Hansen , Paul Mackerras , sparclinux@vger.kernel.org, Thomas Gleixner , linux-s390@vger.kernel.org, Jason Gunthorpe , Michael Ellerman , x86@kernel.org, Russell King - ARM Linux , Matthew Wilcox , Steven Price , Tetsuo Handa , Gerald Schaefer , linux-snps-arc@lists.infradead.org, Ingo Molnar , Kees Cook , Masahiro Yamada , Mark Brown , "Kirill A . Shutemov" , Dan Williams , Vlastimil Babka , linux-arm-kernel@lists.infradead.org, Sri Krishna chowdary , Ard Biesheuvel , Greg Kroah-Hartman , linux-mips@vger.kernel.org, Ralf Baechle , linux-kernel@vger.kernel.org, Paul Burton , Mike Rapoport , Vineet Gupta , Martin Schwidefsky , Andrew Morton , linuxppc-dev@lists.ozlabs.org, "David S. Miller" Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-snps-arc" Errors-To: linux-snps-arc-bounces+linux-snps-arc=archiver.kernel.org@lists.infradead.org On 10/21/2019 02:42 AM, Anshuman Khandual wrote: > This adds tests which will validate architecture page table helpers and > other accessors in their compliance with expected generic MM semantics. > This will help various architectures in validating changes to existing > page table helpers or addition of new ones. > > This test covers basic page table entry transformations including but not > limited to old, young, dirty, clean, write, write protect etc at various > level along with populating intermediate entries with next page table page > and validating them. > > Test page table pages are allocated from system memory with required size > and alignments. The mapped pfns at page table levels are derived from a > real pfn representing a valid kernel text symbol. This test gets called > right after page_alloc_init_late(). > > This gets build and run when CONFIG_DEBUG_VM_PGTABLE is selected along with > CONFIG_VM_DEBUG. Architectures willing to subscribe this test also need to > select CONFIG_ARCH_HAS_DEBUG_VM_PGTABLE which for now is limited to x86 and > arm64. Going forward, other architectures too can enable this after fixing > build or runtime problems (if any) with their page table helpers. > > Folks interested in making sure that a given platform's page table helpers > conform to expected generic MM semantics should enable the above config > which will just trigger this test during boot. Any non conformity here will > be reported as an warning which would need to be fixed. This test will help > catch any changes to the agreed upon semantics expected from generic MM and > enable platforms to accommodate it thereafter. > > Cc: Andrew Morton > Cc: Vlastimil Babka > Cc: Greg Kroah-Hartman > Cc: Thomas Gleixner > Cc: Mike Rapoport > Cc: Jason Gunthorpe > Cc: Dan Williams > Cc: Peter Zijlstra > Cc: Michal Hocko > Cc: Mark Rutland > Cc: Mark Brown > Cc: Steven Price > Cc: Ard Biesheuvel > Cc: Masahiro Yamada > Cc: Kees Cook > Cc: Tetsuo Handa > Cc: Matthew Wilcox > Cc: Sri Krishna chowdary > Cc: Dave Hansen > Cc: Russell King - ARM Linux > Cc: Michael Ellerman > Cc: Paul Mackerras > Cc: Martin Schwidefsky > Cc: Heiko Carstens > Cc: "David S. Miller" > Cc: Vineet Gupta > Cc: James Hogan > Cc: Paul Burton > Cc: Ralf Baechle > Cc: Kirill A. Shutemov > Cc: Gerald Schaefer > Cc: Christophe Leroy > Cc: Ingo Molnar > Cc: linux-snps-arc@lists.infradead.org > Cc: linux-mips@vger.kernel.org > Cc: linux-arm-kernel@lists.infradead.org > Cc: linux-ia64@vger.kernel.org > Cc: linuxppc-dev@lists.ozlabs.org > Cc: linux-s390@vger.kernel.org > Cc: linux-sh@vger.kernel.org > Cc: sparclinux@vger.kernel.org > Cc: x86@kernel.org > Cc: linux-kernel@vger.kernel.org > > Tested-by: Christophe Leroy #PPC32 > Suggested-by: Catalin Marinas > Signed-off-by: Andrew Morton > Signed-off-by: Christophe Leroy > Signed-off-by: Anshuman Khandual > --- The cover letter have the exact same title as this patch. I think a cover letter is not necessary for a singleton series. The history (and any other information you don't want to include in the commit message) can be added here, below the '---'. That way it is in the mail but won't be included in the commit. > .../debug/debug-vm-pgtable/arch-support.txt | 34 ++ > arch/arm64/Kconfig | 1 + > arch/x86/Kconfig | 1 + > arch/x86/include/asm/pgtable_64.h | 6 + > include/asm-generic/pgtable.h | 6 + > init/main.c | 1 + > lib/Kconfig.debug | 21 ++ > mm/Makefile | 1 + > mm/debug_vm_pgtable.c | 388 +++++++++++++++++++++ > 9 files changed, 459 insertions(+) > create mode 100644 Documentation/features/debug/debug-vm-pgtable/arch-support.txt > create mode 100644 mm/debug_vm_pgtable.c > > diff --git a/Documentation/features/debug/debug-vm-pgtable/arch-support.txt b/Documentation/features/debug/debug-vm-pgtable/arch-support.txt > new file mode 100644 > index 0000000..d6b8185 > --- /dev/null > +++ b/Documentation/features/debug/debug-vm-pgtable/arch-support.txt > @@ -0,0 +1,34 @@ > +# > +# Feature name: debug-vm-pgtable > +# Kconfig: ARCH_HAS_DEBUG_VM_PGTABLE > +# description: arch supports pgtable tests for semantics compliance > +# > + ----------------------- > + | arch |status| > + ----------------------- > + | alpha: | TODO | > + | arc: | TODO | > + | arm: | TODO | > + | arm64: | ok | > + | c6x: | TODO | > + | csky: | TODO | > + | h8300: | TODO | > + | hexagon: | TODO | > + | ia64: | TODO | > + | m68k: | TODO | > + | microblaze: | TODO | > + | mips: | TODO | > + | nds32: | TODO | > + | nios2: | TODO | > + | openrisc: | TODO | > + | parisc: | TODO | > + | powerpc: | TODO | Say ok on ppc32 > + | riscv: | TODO | > + | s390: | TODO | > + | sh: | TODO | > + | sparc: | TODO | > + | um: | TODO | > + | unicore32: | TODO | > + | x86: | ok | > + | xtensa: | TODO | > + ----------------------- > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index 1b6ea5a..ea62c87 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -11,6 +11,7 @@ config ARM64 > select ACPI_PPTT if ACPI > select ARCH_CLOCKSOURCE_DATA > select ARCH_HAS_DEBUG_VIRTUAL > + select ARCH_HAS_DEBUG_VM_PGTABLE > select ARCH_HAS_DEVMEM_IS_ALLOWED > select ARCH_HAS_DMA_COHERENT_TO_PFN > select ARCH_HAS_DMA_PREP_COHERENT > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig > index abe822d..13c9bd9 100644 > --- a/arch/x86/Kconfig > +++ b/arch/x86/Kconfig > @@ -61,6 +61,7 @@ config X86 > select ARCH_CLOCKSOURCE_INIT > select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI > select ARCH_HAS_DEBUG_VIRTUAL > + select ARCH_HAS_DEBUG_VM_PGTABLE > select ARCH_HAS_DEVMEM_IS_ALLOWED > select ARCH_HAS_ELF_RANDOMIZE > select ARCH_HAS_FAST_MULTIPLIER diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 3e56c9c2f16e..c50d7cfa566b 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -120,6 +120,7 @@ config PPC # select ARCH_32BIT_OFF_T if PPC32 select ARCH_HAS_DEBUG_VIRTUAL + select ARCH_HAS_DEBUG_VM_PGTABLE if PPC32 select ARCH_HAS_DEVMEM_IS_ALLOWED select ARCH_HAS_ELF_RANDOMIZE select ARCH_HAS_FORTIFY_SOURCE > diff --git a/arch/x86/include/asm/pgtable_64.h b/arch/x86/include/asm/pgtable_64.h > index 0b6c4042..fb0e76d 100644 > --- a/arch/x86/include/asm/pgtable_64.h > +++ b/arch/x86/include/asm/pgtable_64.h > @@ -53,6 +53,12 @@ static inline void sync_initial_page_table(void) { } > > struct mm_struct; > > +#define mm_p4d_folded mm_p4d_folded > +static inline bool mm_p4d_folded(struct mm_struct *mm) > +{ > + return !pgtable_l5_enabled(); > +} > + > void set_pte_vaddr_p4d(p4d_t *p4d_page, unsigned long vaddr, pte_t new_pte); > void set_pte_vaddr_pud(pud_t *pud_page, unsigned long vaddr, pte_t new_pte); > > diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h > index 9cdcbc7..9eb02e1 100644 > --- a/include/asm-generic/pgtable.h > +++ b/include/asm-generic/pgtable.h > @@ -1168,6 +1168,12 @@ static inline bool arch_has_pfn_modify_check(void) > # define PAGE_KERNEL_EXEC PAGE_KERNEL > #endif > > +#ifdef CONFIG_DEBUG_VM_PGTABLE > +extern void debug_vm_pgtable(void); > +#else > +static inline void debug_vm_pgtable(void) { } > +#endif > + > #endif /* !__ASSEMBLY__ */ > > #ifndef io_remap_pfn_range > diff --git a/init/main.c b/init/main.c > index 91f6ebb..af8379e 100644 > --- a/init/main.c > +++ b/init/main.c > @@ -1185,6 +1185,7 @@ static noinline void __init kernel_init_freeable(void) > sched_init_smp(); > > page_alloc_init_late(); > + debug_vm_pgtable(); > /* Initialize page ext after all struct pages are initialized. */ > page_ext_init(); > > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > index 9c60d7d..cf48d95 100644 > --- a/lib/Kconfig.debug > +++ b/lib/Kconfig.debug > @@ -690,6 +690,27 @@ config DEBUG_VM_PGFLAGS > > If unsure, say N. > > +config ARCH_HAS_DEBUG_VM_PGTABLE > + bool > + help > + An architecture should select this when it can successfully > + build and run DEBUG_VM_PGTABLE. > + > +config DEBUG_VM_PGTABLE > + bool "Debug arch page table for semantics compliance" > + depends on MMU > + depends on DEBUG_VM > + depends on ARCH_HAS_DEBUG_VM_PGTABLE > + help > + This option provides a debug method which can be used to test > + architecture page table helper functions on various platforms in > + verifying if they comply with expected generic MM semantics. This > + will help architecture code in making sure that any changes or > + new additions of these helpers still conform to expected > + semantics of the generic MM. > + > + If unsure, say N. > + Would be nice to have that one also indented like the other DEBUG_VM_XXXXX (see below). Stack utilization instrumentation (DEBUG_STACK_USAGE) [N/y/?] n Debug VM (DEBUG_VM) [N/y/?] (NEW) y Debug VMA caching (DEBUG_VM_VMACACHE) [N/y/?] (NEW) Debug VM red-black trees (DEBUG_VM_RB) [N/y/?] (NEW) Debug page-flags operations (DEBUG_VM_PGFLAGS) [N/y/?] (NEW) Debug arch page table for semantics compliance (DEBUG_VM_PGTABLE) [N/y/?] (NEW) Debug VM translations (DEBUG_VIRTUAL) [N/y/?] n For that, just move config ARCH_HAS_DEBUG_VM_PGTABLE somewhere else, maybe before DEBUG_VM or just after DEBUG_VM_PGTABLE > config ARCH_HAS_DEBUG_VIRTUAL > bool > > diff --git a/mm/Makefile b/mm/Makefile > index d996846..2f085b9 100644 > --- a/mm/Makefile > +++ b/mm/Makefile > @@ -86,6 +86,7 @@ obj-$(CONFIG_HWPOISON_INJECT) += hwpoison-inject.o > obj-$(CONFIG_DEBUG_KMEMLEAK) += kmemleak.o > obj-$(CONFIG_DEBUG_KMEMLEAK_TEST) += kmemleak-test.o > obj-$(CONFIG_DEBUG_RODATA_TEST) += rodata_test.o > +obj-$(CONFIG_DEBUG_VM_PGTABLE) += debug_vm_pgtable.o > obj-$(CONFIG_PAGE_OWNER) += page_owner.o > obj-$(CONFIG_CLEANCACHE) += cleancache.o > obj-$(CONFIG_MEMORY_ISOLATION) += page_isolation.o > diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c > new file mode 100644 > index 0000000..9472566 > --- /dev/null > +++ b/mm/debug_vm_pgtable.c > @@ -0,0 +1,388 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * This kernel test validates architecture page table helpers and > + * accessors and helps in verifying their continued compliance with > + * expected generic MM semantics. > + * > + * Copyright (C) 2019 ARM Ltd. > + * > + * Author: Anshuman Khandual > + */ > +#define pr_fmt(fmt) "arch_pgtable_test: %s " fmt, __func__ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +/* > + * Basic operations > + * > + * mkold(entry) = An old and not a young entry > + * mkyoung(entry) = A young and not an old entry > + * mkdirty(entry) = A dirty and not a clean entry > + * mkclean(entry) = A clean and not a dirty entry > + * mkwrite(entry) = A write and not a write protected entry > + * wrprotect(entry) = A write protected and not a write entry > + * pxx_bad(entry) = A mapped and non-table entry > + * pxx_same(entry1, entry2) = Both entries hold the exact same value > + */ > +#define VMFLAGS (VM_READ|VM_WRITE|VM_EXEC) > + > +/* > + * On s390 platform, the lower 12 bits are used to identify given page table > + * entry type and for other arch specific requirements. But these bits might > + * affect the ability to clear entries with pxx_clear(). So while loading up > + * the entries skip all lower 12 bits in order to accommodate s390 platform. > + * It does not have affect any other platform. > + */ > +#define RANDOM_ORVALUE (0xfffffffffffff000UL) > +#define RANDOM_NZVALUE (0xff) > + > +static void __init pte_basic_tests(unsigned long pfn, pgprot_t prot) > +{ > + pte_t pte = pfn_pte(pfn, prot); > + > + WARN_ON(!pte_same(pte, pte)); > + WARN_ON(!pte_young(pte_mkyoung(pte))); > + WARN_ON(!pte_dirty(pte_mkdirty(pte))); > + WARN_ON(!pte_write(pte_mkwrite(pte))); > + WARN_ON(pte_young(pte_mkold(pte))); > + WARN_ON(pte_dirty(pte_mkclean(pte))); > + WARN_ON(pte_write(pte_wrprotect(pte))); > +} > + > +#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE > +static void __init pmd_basic_tests(unsigned long pfn, pgprot_t prot) > +{ > + pmd_t pmd = pfn_pmd(pfn, prot); > + > + WARN_ON(!pmd_same(pmd, pmd)); > + WARN_ON(!pmd_young(pmd_mkyoung(pmd))); > + WARN_ON(!pmd_dirty(pmd_mkdirty(pmd))); > + WARN_ON(!pmd_write(pmd_mkwrite(pmd))); > + WARN_ON(pmd_young(pmd_mkold(pmd))); > + WARN_ON(pmd_dirty(pmd_mkclean(pmd))); > + WARN_ON(pmd_write(pmd_wrprotect(pmd))); > + /* > + * A huge page does not point to next level page table > + * entry. Hence this must qualify as pmd_bad(). > + */ > + WARN_ON(!pmd_bad(pmd_mkhuge(pmd))); > +} > +#else > +static void __init pmd_basic_tests(unsigned long pfn, pgprot_t prot) { } > +#endif > + > +#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD > +static void __init pud_basic_tests(unsigned long pfn, pgprot_t prot) > +{ > + pud_t pud = pfn_pud(pfn, prot); > + > + WARN_ON(!pud_same(pud, pud)); > + WARN_ON(!pud_young(pud_mkyoung(pud))); > + WARN_ON(!pud_write(pud_mkwrite(pud))); > + WARN_ON(pud_write(pud_wrprotect(pud))); > + WARN_ON(pud_young(pud_mkold(pud))); > + > + if (mm_pmd_folded(mm) || __is_defined(ARCH_HAS_4LEVEL_HACK)) > + return; > + > + /* > + * A huge page does not point to next level page table > + * entry. Hence this must qualify as pud_bad(). > + */ > + WARN_ON(!pud_bad(pud_mkhuge(pud))); > +} > +#else > +static void __init pud_basic_tests(unsigned long pfn, pgprot_t prot) { } > +#endif > + > +static void __init p4d_basic_tests(unsigned long pfn, pgprot_t prot) > +{ > + p4d_t p4d; > + > + memset(&p4d, RANDOM_NZVALUE, sizeof(p4d_t)); > + WARN_ON(!p4d_same(p4d, p4d)); > +} > + > +static void __init pgd_basic_tests(unsigned long pfn, pgprot_t prot) > +{ > + pgd_t pgd; > + > + memset(&pgd, RANDOM_NZVALUE, sizeof(pgd_t)); > + WARN_ON(!pgd_same(pgd, pgd)); > +} > + > +#ifndef __ARCH_HAS_4LEVEL_HACK > +static void __init pud_clear_tests(struct mm_struct *mm, pud_t *pudp) > +{ > + pud_t pud = READ_ONCE(*pudp); > + > + if (mm_pmd_folded(mm)) > + return; > + > + pud = __pud(pud_val(pud) | RANDOM_ORVALUE); > + WRITE_ONCE(*pudp, pud); > + pud_clear(pudp); > + pud = READ_ONCE(*pudp); > + WARN_ON(!pud_none(pud)); > +} > + > +static void __init pud_populate_tests(struct mm_struct *mm, pud_t *pudp, > + pmd_t *pmdp) > +{ > + pud_t pud; > + > + if (mm_pmd_folded(mm)) > + return; > + /* > + * This entry points to next level page table page. > + * Hence this must not qualify as pud_bad(). > + */ > + pmd_clear(pmdp); > + pud_clear(pudp); > + pud_populate(mm, pudp, pmdp); > + pud = READ_ONCE(*pudp); > + WARN_ON(pud_bad(pud)); > +} > +#else > +static void __init pud_clear_tests(struct mm_struct *mm, pud_t *pudp) { } > +static void __init pud_populate_tests(struct mm_struct *mm, pud_t *pudp, > + pmd_t *pmdp) > +{ > +} > +#endif > + > +#ifndef __ARCH_HAS_5LEVEL_HACK > +static void __init p4d_clear_tests(struct mm_struct *mm, p4d_t *p4dp) > +{ > + p4d_t p4d = READ_ONCE(*p4dp); > + > + if (mm_pud_folded(mm)) > + return; > + > + p4d = __p4d(p4d_val(p4d) | RANDOM_ORVALUE); > + WRITE_ONCE(*p4dp, p4d); > + p4d_clear(p4dp); > + p4d = READ_ONCE(*p4dp); > + WARN_ON(!p4d_none(p4d)); > +} > + > +static void __init p4d_populate_tests(struct mm_struct *mm, p4d_t *p4dp, > + pud_t *pudp) > +{ > + p4d_t p4d; > + > + if (mm_pud_folded(mm)) > + return; > + > + /* > + * This entry points to next level page table page. > + * Hence this must not qualify as p4d_bad(). > + */ > + pud_clear(pudp); > + p4d_clear(p4dp); > + p4d_populate(mm, p4dp, pudp); > + p4d = READ_ONCE(*p4dp); > + WARN_ON(p4d_bad(p4d)); > +} > + > +static void __init pgd_clear_tests(struct mm_struct *mm, pgd_t *pgdp) > +{ > + pgd_t pgd = READ_ONCE(*pgdp); > + > + if (mm_p4d_folded(mm)) > + return; > + > + pgd = __pgd(pgd_val(pgd) | RANDOM_ORVALUE); > + WRITE_ONCE(*pgdp, pgd); > + pgd_clear(pgdp); > + pgd = READ_ONCE(*pgdp); > + WARN_ON(!pgd_none(pgd)); > +} > + > +static void __init pgd_populate_tests(struct mm_struct *mm, pgd_t *pgdp, > + p4d_t *p4dp) > +{ > + pgd_t pgd; > + > + if (mm_p4d_folded(mm)) > + return; > + > + /* > + * This entry points to next level page table page. > + * Hence this must not qualify as pgd_bad(). > + */ > + p4d_clear(p4dp); > + pgd_clear(pgdp); > + pgd_populate(mm, pgdp, p4dp); > + pgd = READ_ONCE(*pgdp); > + WARN_ON(pgd_bad(pgd)); > +} > +#else > +static void __init p4d_clear_tests(struct mm_struct *mm, p4d_t *p4dp) { } > +static void __init pgd_clear_tests(struct mm_struct *mm, pgd_t *pgdp) { } > +static void __init p4d_populate_tests(struct mm_struct *mm, p4d_t *p4dp, > + pud_t *pudp) > +{ > +} > +static void __init pgd_populate_tests(struct mm_struct *mm, pgd_t *pgdp, > + p4d_t *p4dp) > +{ > +} > +#endif > + > +static void __init pte_clear_tests(struct mm_struct *mm, pte_t *ptep) > +{ > + pte_t pte = READ_ONCE(*ptep); > + > + pte = __pte(pte_val(pte) | RANDOM_ORVALUE); > + WRITE_ONCE(*ptep, pte); > + pte_clear(mm, 0, ptep); > + pte = READ_ONCE(*ptep); > + WARN_ON(!pte_none(pte)); > +} > + > +static void __init pmd_clear_tests(struct mm_struct *mm, pmd_t *pmdp) > +{ > + pmd_t pmd = READ_ONCE(*pmdp); > + > + pmd = __pmd(pmd_val(pmd) | RANDOM_ORVALUE); > + WRITE_ONCE(*pmdp, pmd); > + pmd_clear(pmdp); > + pmd = READ_ONCE(*pmdp); > + WARN_ON(!pmd_none(pmd)); > +} > + > +static void __init pmd_populate_tests(struct mm_struct *mm, pmd_t *pmdp, > + pgtable_t pgtable) > +{ > + pmd_t pmd; > + > + /* > + * This entry points to next level page table page. > + * Hence this must not qualify as pmd_bad(). > + */ > + pmd_clear(pmdp); > + pmd_populate(mm, pmdp, pgtable); > + pmd = READ_ONCE(*pmdp); > + WARN_ON(pmd_bad(pmd)); > +} > + > +static unsigned long __init get_random_vaddr(void) > +{ > + unsigned long random_vaddr, random_pages, total_user_pages; > + > + total_user_pages = (TASK_SIZE - FIRST_USER_ADDRESS) / PAGE_SIZE; > + > + random_pages = get_random_long() % total_user_pages; > + random_vaddr = FIRST_USER_ADDRESS + random_pages * PAGE_SIZE; > + > + WARN_ON((random_vaddr > TASK_SIZE) || > + (random_vaddr < FIRST_USER_ADDRESS)); > + return random_vaddr; > +} > + > +void __init debug_vm_pgtable(void) > +{ > + struct mm_struct *mm; > + pgd_t *pgdp; > + p4d_t *p4dp, *saved_p4dp; > + pud_t *pudp, *saved_pudp; > + pmd_t *pmdp, *saved_pmdp, pmd; > + pte_t *ptep; > + pgtable_t saved_ptep; > + pgprot_t prot; > + phys_addr_t paddr; > + unsigned long vaddr, pte_aligned, pmd_aligned; > + unsigned long pud_aligned, p4d_aligned, pgd_aligned; I think an information message would be nice: diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c index 9472566b7e53..ed7cc3dfc968 100644 --- a/mm/debug_vm_pgtable.c +++ b/mm/debug_vm_pgtable.c @@ -313,6 +313,8 @@ void __init debug_vm_pgtable(void) unsigned long vaddr, pte_aligned, pmd_aligned; unsigned long pud_aligned, p4d_aligned, pgd_aligned; + pr_info("Validating architecture page table helpers\n"); + prot = vm_get_page_prot(VMFLAGS); vaddr = get_random_vaddr(); mm = mm_alloc(); Christophe > + > + prot = vm_get_page_prot(VMFLAGS); > + vaddr = get_random_vaddr(); > + mm = mm_alloc(); > + if (!mm) { > + pr_err("mm_struct allocation failed\n"); > + return; > + } > + > + /* > + * PFN for mapping at PTE level is determined from a standard kernel > + * text symbol. But pfns for higher page table levels are derived by > + * masking lower bits of this real pfn. These derived pfns might not > + * exist on the platform but that does not really matter as pfn_pxx() > + * helpers will still create appropriate entries for the test. This > + * helps avoid large memory block allocations to be used for mapping > + * at higher page table levels. > + */ > + WARN_ON(!virt_addr_valid(&start_kernel)); > + paddr = __pa(&start_kernel); > + > + pte_aligned = (paddr & PAGE_MASK) >> PAGE_SHIFT; > + pmd_aligned = (paddr & PMD_MASK) >> PAGE_SHIFT; > + pud_aligned = (paddr & PUD_MASK) >> PAGE_SHIFT; > + p4d_aligned = (paddr & P4D_MASK) >> PAGE_SHIFT; > + pgd_aligned = (paddr & PGDIR_MASK) >> PAGE_SHIFT; > + > + pgdp = pgd_offset(mm, vaddr); > + p4dp = p4d_alloc(mm, pgdp, vaddr); > + pudp = pud_alloc(mm, p4dp, vaddr); > + pmdp = pmd_alloc(mm, pudp, vaddr); > + ptep = pte_alloc_map(mm, pmdp, vaddr); > + > + /* > + * Save all the page table page addresses as the page table > + * entries will be used for testing with random or garbage > + * values. These saved addresses will be used for freeing > + * page table pages. > + */ > + pmd = READ_ONCE(*pmdp); > + saved_p4dp = p4d_offset(pgdp, 0UL); > + saved_pudp = pud_offset(p4dp, 0UL); > + saved_pmdp = pmd_offset(pudp, 0UL); > + saved_ptep = pmd_pgtable(pmd); > + > + pte_basic_tests(pte_aligned, prot); > + pmd_basic_tests(pmd_aligned, prot); > + pud_basic_tests(pud_aligned, prot); > + p4d_basic_tests(p4d_aligned, prot); > + pgd_basic_tests(pgd_aligned, prot); > + > + pte_clear_tests(mm, ptep); > + pmd_clear_tests(mm, pmdp); > + pud_clear_tests(mm, pudp); > + p4d_clear_tests(mm, p4dp); > + pgd_clear_tests(mm, pgdp); > + > + pte_unmap(ptep); > + > + pmd_populate_tests(mm, pmdp, saved_ptep); > + pud_populate_tests(mm, pudp, saved_pmdp); > + p4d_populate_tests(mm, p4dp, saved_pudp); > + pgd_populate_tests(mm, pgdp, saved_p4dp); > + > + p4d_free(mm, saved_p4dp); > + pud_free(mm, saved_pudp); > + pmd_free(mm, saved_pmdp); > + pte_free(mm, saved_ptep); > + > + mm_dec_nr_puds(mm); > + mm_dec_nr_pmds(mm); > + mm_dec_nr_ptes(mm); > + __mmdrop(mm); > +} > _______________________________________________ linux-snps-arc mailing list linux-snps-arc@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-snps-arc