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a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777469993; bh=sDZpiRzsQemL+9DqGDzdUHvJ8tPGWBEbveTIR7Y1hd0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=pJMgz7rANvW3gltIkCoxOmN4OeT/8No7Cp1LNZNgfeI0ERfnTBJV7X5VA9FsFlsBQ AkoG4qksc3arluR9/BXwUeN2v8vDomDJR4s/cIZa61IvEufufumwfXANLiu0VTO9Ar 4/rks236tYY0G6/gif4nwLOVloLD0TccVWymjdpcOWyoEe4YaiOykti2NUgoYASke7 MhRh3K1y4/v+UR4paeYbNAfM3yinnlpo3/1VnW3jG/w+lW2cbiU+7I3kPHDGNCLOgj IAN0zzX3m1ic3nirBkZDMHk++ARwWtCfZT1pisHHN79hfyYM3M01Lkc2epsT+rhWtK /2IZuGHxw9WIg== From: Pratyush Yadav To: Mike Rapoport , Pasha Tatashin , Pratyush Yadav , Alexander Graf , Muchun Song , Oscar Salvador , David Hildenbrand , Andrew Morton , Jason Miu Cc: kexec@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH 04/12] kho: add callback for table pages Date: Wed, 29 Apr 2026 15:39:06 +0200 Message-ID: <20260429133928.850721-5-pratyush@kernel.org> X-Mailer: git-send-email 2.54.0.545.g6539524ca2-goog In-Reply-To: <20260429133928.850721-1-pratyush@kernel.org> References: <20260429133928.850721-1-pratyush@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Stat-Signature: xxxe3gzm5d1ypj99ai4hdqgc3cmm45br X-Rspam-User: X-Rspamd-Queue-Id: 15CC2140002 X-Rspamd-Server: rspam07 X-HE-Tag: 1777469994-135522 X-HE-Meta: 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 YG3Tkacq MvNpXKBCDGALOqpRXAAco58aYa01e49pDNv9RSwcY3BtMyTuZx5nswbzFRoNGY0e3oosAW2YLhCIcAxCJvmiieB/sYpSfTpgNg5wEPp4taMBx35YnlNrazGRoE3DJ9+h9aAsTyNo3fYP60PkjkXmrltsqAjHFnZoQbSy0qf5ks/UD/PkzMWONDMdAkOdNFYvahMDSksg725m7+8jjtDXuO6at5jzfO69WzLAIAzV+YGYqJbTuYUzOHbtPg0+61kQuPZogfBBZsnBS2QQ= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: "Pratyush Yadav (Google)" The KHO memory preservation radix tree does not mark the table pages themselves as scratch. This is done to avoid a circular dependency where preserving a page can lead of allocating other preserved pages. This means any walker looking for free ranges of memory outside of scratch areas will ignore the table Add a table callback that is invoked for each table page. The callback is given the physical address of the table page. Signed-off-by: Pratyush Yadav (Google) --- include/linux/kho_radix_tree.h | 3 +++ kernel/liveupdate/kexec_handover.c | 12 ++++++++++++ 2 files changed, 15 insertions(+) diff --git a/include/linux/kho_radix_tree.h b/include/linux/kho_radix_tree.h index 030da6399d28..fe7151d89361 100644 --- a/include/linux/kho_radix_tree.h +++ b/include/linux/kho_radix_tree.h @@ -37,12 +37,15 @@ struct kho_radix_tree { /** * struct kho_radix_walk_cb - Callbacks for KHO radix tree walk. * @key: Called on each present key in the radix tree. + * @table: Called on each table of the radix tree itself. Receives the + * physical address of the page containing the table. * * For each callback, a return value of 0 continues the walk and a non-zero * return value is directly returned to the caller. */ struct kho_radix_walk_cb { int (*key)(unsigned long key); + int (*table)(phys_addr_t phys); }; #ifdef CONFIG_KEXEC_HANDOVER diff --git a/kernel/liveupdate/kexec_handover.c b/kernel/liveupdate/kexec_handover.c index 4a5d1b47799c..94ca831b41c9 100644 --- a/kernel/liveupdate/kexec_handover.c +++ b/kernel/liveupdate/kexec_handover.c @@ -273,6 +273,12 @@ static int kho_radix_walk_leaf(struct kho_radix_leaf *leaf, unsigned long key, unsigned int i; int err; + if (cb->table) { + err = cb->table(virt_to_phys(leaf)); + if (err) + return err; + } + if (!cb->key) return 0; @@ -295,6 +301,12 @@ static int __kho_radix_walk_tree(struct kho_radix_node *root, unsigned int shift; int err; + if (cb->table) { + err = cb->table(virt_to_phys(root)); + if (err) + return err; + } + for (i = 0; i < PAGE_SIZE / sizeof(phys_addr_t); i++) { if (!root->table[i]) continue; -- 2.54.0.545.g6539524ca2-goog