From: Steven Price <steven.price@arm.com> To: Mark Rutland <mark.rutland@arm.com> Cc: x86@kernel.org, "Arnd Bergmann" <arnd@arndb.de>, "Ard Biesheuvel" <ard.biesheuvel@linaro.org>, "Peter Zijlstra" <peterz@infradead.org>, "Catalin Marinas" <catalin.marinas@arm.com>, "Dave Hansen" <dave.hansen@linux.intel.com>, linux-kernel@vger.kernel.org, linux-mm@kvack.org, "Jérôme Glisse" <jglisse@redhat.com>, "Ingo Molnar" <mingo@redhat.com>, "Borislav Petkov" <bp@alien8.de>, "Andy Lutomirski" <luto@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>, "James Morse" <james.morse@arm.com>, "Thomas Gleixner" <tglx@linutronix.de>, "Will Deacon" <will@kernel.org>, "Andrew Morton" <akpm@linux-foundation.org>, linux-arm-kernel@lists.infradead.org, "Liang, Kan" <kan.liang@linux.intel.com> Subject: Re: [PATCH v9 19/21] mm: Add generic ptdump Date: Wed, 24 Jul 2019 17:36:45 +0100 [thread overview] Message-ID: <ee707646-0196-63bb-45cc-6b949ae9530e@arm.com> (raw) In-Reply-To: <20190723095747.GB8085@lakrids.cambridge.arm.com> On 23/07/2019 10:57, Mark Rutland wrote: > On Mon, Jul 22, 2019 at 04:42:08PM +0100, Steven Price wrote: >> Add a generic version of page table dumping that architectures can >> opt-in to >> >> Signed-off-by: Steven Price <steven.price@arm.com> > > [...] > >> +#ifdef CONFIG_KASAN >> +/* >> + * This is an optimization for KASAN=y case. Since all kasan page tables >> + * eventually point to the kasan_early_shadow_page we could call note_page() >> + * right away without walking through lower level page tables. This saves >> + * us dozens of seconds (minutes for 5-level config) while checking for >> + * W+X mapping or reading kernel_page_tables debugfs file. >> + */ >> +static inline bool kasan_page_table(struct ptdump_state *st, void *pt, >> + unsigned long addr) >> +{ >> + if (__pa(pt) == __pa(kasan_early_shadow_pmd) || >> +#ifdef CONFIG_X86 >> + (pgtable_l5_enabled() && >> + __pa(pt) == __pa(kasan_early_shadow_p4d)) || >> +#endif >> + __pa(pt) == __pa(kasan_early_shadow_pud)) { >> + st->note_page(st, addr, 5, pte_val(kasan_early_shadow_pte[0])); >> + return true; >> + } >> + return false; > > Having you tried this with CONFIG_DEBUG_VIRTUAL? > > The kasan_early_shadow_pmd is a kernel object rather than a linear map > object, so you should use __pa_symbol for that. Thanks for pointing that out - it is indeed broken on arm64. This was moved from x86 where CONFIG_DEBUG_VIRTUAL doesn't seem to pick this up. There is actually a problem here that 'pt' might not be in the linear map (so __pa(pt) barfs on arm64 as well as kasan_early_shadow_p?d). It looks like having the comparisons of the form "pt == lm_alias(kasan_early_shadow_p?d)" is probably best. > It's a bit horrid to have to test multiple levels in one function; can't > we check the relevant level inline in each of the test_p?d funcs? > > They're optional anyway, so they only need to be defined for > CONFIG_KASAN. Good point - removing the test_p?d callbacks when !CONFIG_KASAN simplifies the code. Thanks, Steve
WARNING: multiple messages have this Message-ID (diff)
From: Steven Price <steven.price@arm.com> To: Mark Rutland <mark.rutland@arm.com> Cc: "Dave Hansen" <dave.hansen@linux.intel.com>, "Arnd Bergmann" <arnd@arndb.de>, "Ard Biesheuvel" <ard.biesheuvel@linaro.org>, "Peter Zijlstra" <peterz@infradead.org>, "Catalin Marinas" <catalin.marinas@arm.com>, x86@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, "Jérôme Glisse" <jglisse@redhat.com>, "Ingo Molnar" <mingo@redhat.com>, "Borislav Petkov" <bp@alien8.de>, "Andy Lutomirski" <luto@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>, "James Morse" <james.morse@arm.com>, "Thomas Gleixner" <tglx@linutronix.de>, "Will Deacon" <will@kernel.org>, "Andrew Morton" <akpm@linux-foundation.org>, linux-arm-kernel@lists.infradead.org, "Liang, Kan" <kan.liang@linux.intel.com> Subject: Re: [PATCH v9 19/21] mm: Add generic ptdump Date: Wed, 24 Jul 2019 17:36:45 +0100 [thread overview] Message-ID: <ee707646-0196-63bb-45cc-6b949ae9530e@arm.com> (raw) In-Reply-To: <20190723095747.GB8085@lakrids.cambridge.arm.com> On 23/07/2019 10:57, Mark Rutland wrote: > On Mon, Jul 22, 2019 at 04:42:08PM +0100, Steven Price wrote: >> Add a generic version of page table dumping that architectures can >> opt-in to >> >> Signed-off-by: Steven Price <steven.price@arm.com> > > [...] > >> +#ifdef CONFIG_KASAN >> +/* >> + * This is an optimization for KASAN=y case. Since all kasan page tables >> + * eventually point to the kasan_early_shadow_page we could call note_page() >> + * right away without walking through lower level page tables. This saves >> + * us dozens of seconds (minutes for 5-level config) while checking for >> + * W+X mapping or reading kernel_page_tables debugfs file. >> + */ >> +static inline bool kasan_page_table(struct ptdump_state *st, void *pt, >> + unsigned long addr) >> +{ >> + if (__pa(pt) == __pa(kasan_early_shadow_pmd) || >> +#ifdef CONFIG_X86 >> + (pgtable_l5_enabled() && >> + __pa(pt) == __pa(kasan_early_shadow_p4d)) || >> +#endif >> + __pa(pt) == __pa(kasan_early_shadow_pud)) { >> + st->note_page(st, addr, 5, pte_val(kasan_early_shadow_pte[0])); >> + return true; >> + } >> + return false; > > Having you tried this with CONFIG_DEBUG_VIRTUAL? > > The kasan_early_shadow_pmd is a kernel object rather than a linear map > object, so you should use __pa_symbol for that. Thanks for pointing that out - it is indeed broken on arm64. This was moved from x86 where CONFIG_DEBUG_VIRTUAL doesn't seem to pick this up. There is actually a problem here that 'pt' might not be in the linear map (so __pa(pt) barfs on arm64 as well as kasan_early_shadow_p?d). It looks like having the comparisons of the form "pt == lm_alias(kasan_early_shadow_p?d)" is probably best. > It's a bit horrid to have to test multiple levels in one function; can't > we check the relevant level inline in each of the test_p?d funcs? > > They're optional anyway, so they only need to be defined for > CONFIG_KASAN. Good point - removing the test_p?d callbacks when !CONFIG_KASAN simplifies the code. Thanks, Steve _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2019-07-24 16:36 UTC|newest] Thread overview: 129+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-07-22 15:41 [PATCH v9 00/21] Generic page walk and ptdump Steven Price 2019-07-22 15:41 ` Steven Price 2019-07-22 15:41 ` [PATCH v9 01/21] arc: mm: Add p?d_leaf() definitions Steven Price 2019-07-22 15:41 ` Steven Price 2019-07-22 15:41 ` Steven Price 2019-07-22 15:41 ` [PATCH v9 02/21] arm: " Steven Price 2019-07-22 15:41 ` Steven Price 2019-07-22 15:41 ` [PATCH v9 03/21] arm64: " Steven Price 2019-07-22 15:41 ` Steven Price 2019-07-22 15:41 ` [PATCH v9 04/21] mips: " Steven Price 2019-07-22 15:41 ` Steven Price 2019-07-22 21:47 ` Paul Burton 2019-07-22 21:47 ` Paul Burton 2019-07-24 13:03 ` Steven Price 2019-07-24 13:03 ` Steven Price 2019-07-22 15:41 ` [PATCH v9 05/21] powerpc: " Steven Price 2019-07-22 15:41 ` Steven Price 2019-07-22 15:41 ` Steven Price 2019-07-22 15:41 ` Steven Price 2019-07-22 15:41 ` [PATCH v9 06/21] riscv: " Steven Price 2019-07-22 15:41 ` Steven Price 2019-07-22 15:41 ` Steven Price 2019-07-22 15:41 ` [PATCH v9 07/21] s390: " Steven Price 2019-07-22 15:41 ` Steven Price 2019-07-22 15:41 ` [PATCH v9 08/21] sparc: " Steven Price 2019-07-22 15:41 ` Steven Price 2019-07-22 15:41 ` Steven Price 2019-07-22 15:41 ` [PATCH v9 09/21] x86: " Steven Price 2019-07-22 15:41 ` Steven Price 2019-07-22 15:41 ` [PATCH v9 10/21] mm: Add generic p?d_leaf() macros Steven Price 2019-07-22 15:41 ` Steven Price 2019-07-23 9:41 ` Mark Rutland 2019-07-23 9:41 ` Mark Rutland 2019-07-24 13:48 ` Steven Price 2019-07-24 13:48 ` Steven Price 2019-07-28 11:44 ` Anshuman Khandual 2019-07-28 11:44 ` Anshuman Khandual 2019-07-29 11:38 ` Steven Price 2019-07-29 11:38 ` Steven Price 2019-08-01 6:09 ` Anshuman Khandual 2019-08-01 6:09 ` Anshuman Khandual 2019-08-01 12:22 ` Steven Price 2019-08-01 12:22 ` Steven Price 2019-07-29 12:50 ` Mark Rutland 2019-07-29 12:50 ` Mark Rutland 2019-08-01 6:13 ` Anshuman Khandual 2019-08-01 6:13 ` Anshuman Khandual 2019-07-22 15:42 ` [PATCH v9 11/21] mm: pagewalk: Add p4d_entry() and pgd_entry() Steven Price 2019-07-22 15:42 ` Steven Price 2019-07-23 10:14 ` Mark Rutland 2019-07-23 10:14 ` Mark Rutland 2019-07-24 13:53 ` Steven Price 2019-07-24 13:53 ` Steven Price 2019-07-24 14:09 ` Mark Rutland 2019-07-24 14:09 ` Mark Rutland 2019-07-28 12:33 ` Anshuman Khandual 2019-07-28 12:33 ` Anshuman Khandual 2019-07-29 12:17 ` Steven Price 2019-07-29 12:17 ` Steven Price 2019-07-22 15:42 ` [PATCH v9 12/21] mm: pagewalk: Allow walking without vma Steven Price 2019-07-22 15:42 ` Steven Price 2019-07-28 14:20 ` Anshuman Khandual 2019-07-28 14:20 ` Anshuman Khandual 2019-07-29 12:29 ` Steven Price 2019-07-29 12:29 ` Steven Price 2019-08-01 6:41 ` Anshuman Khandual 2019-08-01 6:41 ` Anshuman Khandual 2019-07-22 15:42 ` [PATCH v9 13/21] mm: pagewalk: Add test_p?d callbacks Steven Price 2019-07-22 15:42 ` Steven Price 2019-07-28 13:41 ` Anshuman Khandual 2019-07-28 13:41 ` Anshuman Khandual 2019-07-29 12:34 ` Steven Price 2019-07-29 12:34 ` Steven Price 2019-07-22 15:42 ` [PATCH v9 14/21] x86: mm: Don't display pages which aren't present in debugfs Steven Price 2019-07-22 15:42 ` Steven Price 2019-07-22 15:42 ` [PATCH v9 15/21] x86: mm: Point to struct seq_file from struct pg_state Steven Price 2019-07-22 15:42 ` Steven Price 2019-07-22 15:42 ` [PATCH v9 16/21] x86: mm+efi: Convert ptdump_walk_pgd_level() to take a mm_struct Steven Price 2019-07-22 15:42 ` Steven Price 2019-07-22 15:42 ` [PATCH v9 17/21] x86: mm: Convert ptdump_walk_pgd_level_debugfs() to take an mm_struct Steven Price 2019-07-22 15:42 ` Steven Price 2019-07-22 15:42 ` [PATCH v9 18/21] x86: mm: Convert ptdump_walk_pgd_level_core() " Steven Price 2019-07-22 15:42 ` Steven Price 2019-07-22 15:42 ` [PATCH v9 19/21] mm: Add generic ptdump Steven Price 2019-07-22 15:42 ` Steven Price 2019-07-23 9:57 ` Mark Rutland 2019-07-23 9:57 ` Mark Rutland 2019-07-24 16:36 ` Steven Price [this message] 2019-07-24 16:36 ` Steven Price 2019-07-29 2:59 ` Anshuman Khandual 2019-07-29 2:59 ` Anshuman Khandual 2019-07-29 13:56 ` Steven Price 2019-07-29 13:56 ` Steven Price 2019-07-22 15:42 ` [PATCH v9 20/21] x86: mm: Convert dump_pagetables to use walk_page_range Steven Price 2019-07-22 15:42 ` Steven Price 2019-07-22 15:42 ` [PATCH v9 21/21] arm64: mm: Convert mm/dump.c to use walk_page_range() Steven Price 2019-07-22 15:42 ` Steven Price 2019-07-23 6:39 ` [PATCH v9 00/21] Generic page walk and ptdump Anshuman Khandual 2019-07-23 6:39 ` Anshuman Khandual 2019-07-24 13:35 ` Steven Price 2019-07-24 13:35 ` Steven Price 2019-07-25 9:09 ` Anshuman Khandual 2019-07-25 9:09 ` Anshuman Khandual 2019-07-25 9:30 ` Will Deacon 2019-07-25 9:30 ` Will Deacon 2019-07-26 6:03 ` Anshuman Khandual 2019-07-26 6:03 ` Anshuman Khandual 2019-07-25 10:15 ` Steven Price 2019-07-25 10:15 ` Steven Price 2019-07-23 10:16 ` Mark Rutland 2019-07-23 10:16 ` Mark Rutland 2019-07-24 13:35 ` Steven Price 2019-07-24 13:35 ` Steven Price 2019-07-24 13:57 ` Thomas Gleixner 2019-07-24 13:57 ` Thomas Gleixner 2019-07-24 14:07 ` Mark Rutland 2019-07-24 14:07 ` Mark Rutland 2019-07-24 14:18 ` Steven Price 2019-07-24 14:18 ` Steven Price 2019-07-24 14:37 ` Thomas Gleixner 2019-07-24 14:37 ` Thomas Gleixner 2019-07-28 11:20 ` Anshuman Khandual 2019-07-28 11:20 ` Anshuman Khandual 2019-07-29 11:32 ` Steven Price 2019-07-29 11:32 ` Steven Price 2019-07-31 9:27 ` Sven Schnelle 2019-07-31 9:27 ` Sven Schnelle 2019-07-31 11:18 ` Steven Price 2019-07-31 11:18 ` Steven Price
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