From: Vivek Kumar <quic_vivekuma@quicinc.com> To: <corbet@lwn.net>, <catalin.marinas@arm.com>, <will@kernel.org>, <tglx@linutronix.de>, <maz@kernel.org>, <axboe@kernel.dk>, <rafael@kernel.org>, <akpm@linux-foundation.org>, <linux-doc@vger.kernel.org>, <linux-kernel@vger.kernel.org>, <linux-arm-kernel@lists.infradead.org>, <linux-block@vger.kernel.org>, <linux-pm@vger.kernel.org>, <linux-mm@kvack.org> Cc: <len.brown@intel.com>, <pavel@ucw.cz>, <paulmck@kernel.org>, <bp@suse.de>, <keescook@chromium.org>, <songmuchun@bytedance.com>, <rdunlap@infradead.org>, <damien.lemoal@opensource.wdc.com>, <pasha.tatashin@soleen.com>, <tabba@google.com>, <ardb@kernel.org>, <tsoni@quicinc.com>, <quic_psodagud@quicinc.com>, <quic_svaddagi@quicinc.com>, Vivek Kumar <quic_vivekuma@quicinc.com>, Prasanna Kumar <quic_kprasan@quicinc.com> Subject: [RFC 5/6] Hibernate: Add check for pte_valid in saveable page Date: Wed, 18 May 2022 13:18:40 +0530 [thread overview] Message-ID: <1652860121-24092-6-git-send-email-quic_vivekuma@quicinc.com> (raw) In-Reply-To: <1652860121-24092-1-git-send-email-quic_vivekuma@quicinc.com> Add check for pte_valid in saveable page after being checked for the rest. This is required as PTE is removed for pages allocated with dma_alloc_coherent with DMA_ATTR_NO_KERNEL_MAPPING flag set. This patch makes sure that these pages are not considered for snapshot. Signed-off-by: Vivek Kumar <quic_vivekuma@quicinc.com> Signed-off-by: Prasanna Kumar <quic_kprasan@quicinc.com> --- kernel/power/snapshot.c | 43 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c index 2a40675..a6ad2a5 100644 --- a/kernel/power/snapshot.c +++ b/kernel/power/snapshot.c @@ -1308,6 +1308,41 @@ static inline void *saveable_highmem_page(struct zone *z, unsigned long p) } #endif /* CONFIG_HIGHMEM */ +static bool kernel_pte_present(struct page *page) +{ + pgd_t *pgdp; + p4d_t *p4dp; + pud_t *pudp, pud; + pmd_t *pmdp, pmd; + pte_t *ptep; + unsigned long addr = (unsigned long)page_address(page); + + pgdp = pgd_offset_k(addr); + if (pgd_none(READ_ONCE(*pgdp))) + return false; + + p4dp = p4d_offset(pgdp, addr); + if (p4d_none(READ_ONCE(*p4dp))) + return false; + + pudp = pud_offset(p4dp, addr); + pud = READ_ONCE(*pudp); + if (pud_none(pud)) + return false; + if (pud_sect(pud)) + return true; + + pmdp = pmd_offset(pudp, addr); + pmd = READ_ONCE(*pmdp); + if (pmd_none(pmd)) + return false; + if (pmd_sect(pmd)) + return true; + + ptep = pte_offset_kernel(pmdp, addr); + return pte_valid(READ_ONCE(*ptep)); +} + /** * saveable_page - Check if the given page is saveable. * @@ -1341,6 +1376,14 @@ static struct page *saveable_page(struct zone *zone, unsigned long pfn) && (!kernel_page_present(page) || pfn_is_nosave(pfn))) return NULL; + /* + * Even if page is not reserved and if it's not present in kernel PTE; + * don't snapshot it ! This happens to the pages allocated using + * __dma_alloc_coherent with DMA_ATTR_NO_KERNEL_MAPPING flag set. + */ + if (!kernel_pte_present(page)) + return NULL; + if (page_is_guard(page)) return NULL; -- 2.7.4
WARNING: multiple messages have this Message-ID (diff)
From: Vivek Kumar <quic_vivekuma@quicinc.com> To: <corbet@lwn.net>, <catalin.marinas@arm.com>, <will@kernel.org>, <tglx@linutronix.de>, <maz@kernel.org>, <axboe@kernel.dk>, <rafael@kernel.org>, <akpm@linux-foundation.org>, <linux-doc@vger.kernel.org>, <linux-kernel@vger.kernel.org>, <linux-arm-kernel@lists.infradead.org>, <linux-block@vger.kernel.org>, <linux-pm@vger.kernel.org>, <linux-mm@kvack.org> Cc: <len.brown@intel.com>, <pavel@ucw.cz>, <paulmck@kernel.org>, <bp@suse.de>, <keescook@chromium.org>, <songmuchun@bytedance.com>, <rdunlap@infradead.org>, <damien.lemoal@opensource.wdc.com>, <pasha.tatashin@soleen.com>, <tabba@google.com>, <ardb@kernel.org>, <tsoni@quicinc.com>, <quic_psodagud@quicinc.com>, <quic_svaddagi@quicinc.com>, Vivek Kumar <quic_vivekuma@quicinc.com>, Prasanna Kumar <quic_kprasan@quicinc.com> Subject: [RFC 5/6] Hibernate: Add check for pte_valid in saveable page Date: Wed, 18 May 2022 13:18:40 +0530 [thread overview] Message-ID: <1652860121-24092-6-git-send-email-quic_vivekuma@quicinc.com> (raw) In-Reply-To: <1652860121-24092-1-git-send-email-quic_vivekuma@quicinc.com> Add check for pte_valid in saveable page after being checked for the rest. This is required as PTE is removed for pages allocated with dma_alloc_coherent with DMA_ATTR_NO_KERNEL_MAPPING flag set. This patch makes sure that these pages are not considered for snapshot. Signed-off-by: Vivek Kumar <quic_vivekuma@quicinc.com> Signed-off-by: Prasanna Kumar <quic_kprasan@quicinc.com> --- kernel/power/snapshot.c | 43 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c index 2a40675..a6ad2a5 100644 --- a/kernel/power/snapshot.c +++ b/kernel/power/snapshot.c @@ -1308,6 +1308,41 @@ static inline void *saveable_highmem_page(struct zone *z, unsigned long p) } #endif /* CONFIG_HIGHMEM */ +static bool kernel_pte_present(struct page *page) +{ + pgd_t *pgdp; + p4d_t *p4dp; + pud_t *pudp, pud; + pmd_t *pmdp, pmd; + pte_t *ptep; + unsigned long addr = (unsigned long)page_address(page); + + pgdp = pgd_offset_k(addr); + if (pgd_none(READ_ONCE(*pgdp))) + return false; + + p4dp = p4d_offset(pgdp, addr); + if (p4d_none(READ_ONCE(*p4dp))) + return false; + + pudp = pud_offset(p4dp, addr); + pud = READ_ONCE(*pudp); + if (pud_none(pud)) + return false; + if (pud_sect(pud)) + return true; + + pmdp = pmd_offset(pudp, addr); + pmd = READ_ONCE(*pmdp); + if (pmd_none(pmd)) + return false; + if (pmd_sect(pmd)) + return true; + + ptep = pte_offset_kernel(pmdp, addr); + return pte_valid(READ_ONCE(*ptep)); +} + /** * saveable_page - Check if the given page is saveable. * @@ -1341,6 +1376,14 @@ static struct page *saveable_page(struct zone *zone, unsigned long pfn) && (!kernel_page_present(page) || pfn_is_nosave(pfn))) return NULL; + /* + * Even if page is not reserved and if it's not present in kernel PTE; + * don't snapshot it ! This happens to the pages allocated using + * __dma_alloc_coherent with DMA_ATTR_NO_KERNEL_MAPPING flag set. + */ + if (!kernel_pte_present(page)) + return NULL; + if (page_is_guard(page)) return NULL; -- 2.7.4 _______________________________________________ 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:[~2022-05-18 7:49 UTC|newest] Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-05-18 7:48 [RFC 0/6] Bootloader based hibernation Vivek Kumar 2022-05-18 7:48 ` Vivek Kumar 2022-05-18 7:48 ` [RFC 1/6] arm64: hibernate: Introduce new entry point to kernel Vivek Kumar 2022-05-18 7:48 ` Vivek Kumar 2022-05-19 15:27 ` Marc Zyngier 2022-05-19 15:27 ` Marc Zyngier 2022-05-18 7:48 ` [RFC 2/6] PM: Hibernate: Add option to disable disk offset randomization Vivek Kumar 2022-05-18 7:48 ` Vivek Kumar 2022-05-18 12:19 ` Andrew Lunn 2022-05-18 12:19 ` Andrew Lunn 2022-05-18 13:00 ` Christoph Hellwig 2022-05-18 13:00 ` Christoph Hellwig 2022-05-23 20:49 ` Randy Dunlap 2022-05-23 20:49 ` Randy Dunlap 2022-05-18 7:48 ` [RFC 3/6] block: gendisk: Add a new genhd capability flag Vivek Kumar 2022-05-18 7:48 ` Vivek Kumar 2022-05-18 8:08 ` Christoph Hellwig 2022-05-18 8:08 ` Christoph Hellwig 2022-05-18 7:48 ` [RFC 4/6] mm: swap: Add randomization check for swapon/off calls Vivek Kumar 2022-05-18 7:48 ` Vivek Kumar 2022-05-18 12:27 ` Andrew Lunn 2022-05-18 12:27 ` Andrew Lunn 2022-05-18 7:48 ` Vivek Kumar [this message] 2022-05-18 7:48 ` [RFC 5/6] Hibernate: Add check for pte_valid in saveable page Vivek Kumar 2022-05-18 13:09 ` Christoph Hellwig 2022-05-18 13:09 ` Christoph Hellwig 2022-05-18 7:48 ` [RFC 6/6] irqchip/gic-v3: Re-init GIC hardware upon hibernation restore Vivek Kumar 2022-05-18 7:48 ` Vivek Kumar 2022-05-19 7:59 ` Marc Zyngier 2022-05-19 7:59 ` Marc Zyngier 2022-05-18 16:55 ` [RFC 0/6] Bootloader based hibernation Pasha Tatashin 2022-05-18 16:55 ` Pasha Tatashin 2022-05-20 16:43 ` Mark Rutland 2022-05-20 16:43 ` Mark Rutland
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