+ s390-kmsan-implement-the-architecture-specific-functions.patch added to mm-unstable branch

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Andrew Morton

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Jun 19, 2024, 8:59:32 PMJun 19
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The patch titled
Subject: s390/kmsan: implement the architecture-specific functions
has been added to the -mm mm-unstable branch. Its filename is
s390-kmsan-implement-the-architecture-specific-functions.patch

This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/s390-kmsan-implement-the-architecture-specific-functions.patch

This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days

------------------------------------------------------
From: Ilya Leoshkevich <i...@linux.ibm.com>
Subject: s390/kmsan: implement the architecture-specific functions
Date: Wed, 19 Jun 2024 17:44:11 +0200

arch_kmsan_get_meta_or_null() finds the lowcore shadow by querying the
prefix and calling kmsan_get_metadata() again.

kmsan_virt_addr_valid() delegates to virt_addr_valid().

Link: https://lkml.kernel.org/r/20240619154530...@linux.ibm.com
Signed-off-by: Ilya Leoshkevich <i...@linux.ibm.com>
Cc: Alexander Gordeev <agor...@linux.ibm.com>
Cc: Alexander Potapenko <gli...@google.com>
Cc: Christian Borntraeger <bornt...@linux.ibm.com>
Cc: Christoph Lameter <c...@linux.com>
Cc: David Rientjes <rien...@google.com>
Cc: Dmitry Vyukov <dvy...@google.com>
Cc: Heiko Carstens <h...@linux.ibm.com>
Cc: Hyeonggon Yoo <42.h...@gmail.com>
Cc: Joonsoo Kim <iamjoon...@lge.com>
Cc: <kasa...@googlegroups.com>
Cc: Marco Elver <el...@google.com>
Cc: Mark Rutland <mark.r...@arm.com>
Cc: Masami Hiramatsu (Google) <mhir...@kernel.org>
Cc: Pekka Enberg <pen...@kernel.org>
Cc: Roman Gushchin <roman.g...@linux.dev>
Cc: Steven Rostedt (Google) <ros...@goodmis.org>
Cc: Sven Schnelle <sv...@linux.ibm.com>
Cc: Vasily Gorbik <g...@linux.ibm.com>
Cc: Vlastimil Babka <vba...@suse.cz>
Signed-off-by: Andrew Morton <ak...@linux-foundation.org>
---

arch/s390/include/asm/kmsan.h | 59 ++++++++++++++++++++++++++++++++
1 file changed, 59 insertions(+)

--- /dev/null
+++ a/arch/s390/include/asm/kmsan.h
@@ -0,0 +1,59 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_S390_KMSAN_H
+#define _ASM_S390_KMSAN_H
+
+#include <asm/lowcore.h>
+#include <asm/page.h>
+#include <linux/kmsan.h>
+#include <linux/mmzone.h>
+#include <linux/stddef.h>
+
+#ifndef MODULE
+
+static inline bool is_lowcore_addr(void *addr)
+{
+ return addr >= (void *)&S390_lowcore &&
+ addr < (void *)(&S390_lowcore + 1);
+}
+
+static inline void *arch_kmsan_get_meta_or_null(void *addr, bool is_origin)
+{
+ if (is_lowcore_addr(addr)) {
+ /*
+ * Different lowcores accessed via S390_lowcore are described
+ * by the same struct page. Resolve the prefix manually in
+ * order to get a distinct struct page.
+ */
+ addr += (void *)lowcore_ptr[raw_smp_processor_id()] -
+ (void *)&S390_lowcore;
+ if (WARN_ON_ONCE(is_lowcore_addr(addr)))
+ return NULL;
+ return kmsan_get_metadata(addr, is_origin);
+ }
+ return NULL;
+}
+
+static inline bool kmsan_virt_addr_valid(void *addr)
+{
+ bool ret;
+
+ /*
+ * pfn_valid() relies on RCU, and may call into the scheduler on exiting
+ * the critical section. However, this would result in recursion with
+ * KMSAN. Therefore, disable preemption here, and re-enable preemption
+ * below while suppressing reschedules to avoid recursion.
+ *
+ * Note, this sacrifices occasionally breaking scheduling guarantees.
+ * Although, a kernel compiled with KMSAN has already given up on any
+ * performance guarantees due to being heavily instrumented.
+ */
+ preempt_disable();
+ ret = virt_addr_valid(addr);
+ preempt_enable_no_resched();
+
+ return ret;
+}
+
+#endif /* !MODULE */
+
+#endif /* _ASM_S390_KMSAN_H */
_

Patches currently in -mm which might be from i...@linux.ibm.com are

ftrace-unpoison-ftrace_regs-in-ftrace_ops_list_func.patch
kmsan-make-the-tests-compatible-with-kmsanpanic=1.patch
kmsan-disable-kmsan-when-deferred_struct_page_init-is-enabled.patch
kmsan-increase-the-maximum-store-size-to-4096.patch
kmsan-fix-is_bad_asm_addr-on-arches-with-overlapping-address-spaces.patch
kmsan-fix-kmsan_copy_to_user-on-arches-with-overlapping-address-spaces.patch
kmsan-remove-a-useless-assignment-from-kmsan_vmap_pages_range_noflush.patch
kmsan-remove-an-x86-specific-include-from-kmsanh.patch
kmsan-expose-kmsan_get_metadata.patch
kmsan-export-panic_on_kmsan.patch
kmsan-allow-disabling-kmsan-checks-for-the-current-task.patch
kmsan-introduce-memset_no_sanitize_memory.patch
kmsan-support-slab_poison.patch
kmsan-use-align_down-in-kmsan_get_metadata.patch
kmsan-do-not-round-up-pg_data_t-size.patch
mm-slub-let-kmsan-access-metadata.patch
mm-slub-disable-kmsan-when-checking-the-padding-bytes.patch
mm-kfence-disable-kmsan-when-checking-the-canary.patch
lib-zlib-unpoison-dfltcc-output-buffers.patch
kmsan-accept-ranges-starting-with-0-on-s390.patch
s390-boot-turn-off-kmsan.patch
s390-use-a-larger-stack-for-kmsan.patch
s390-boot-add-the-kmsan-runtime-stub.patch
s390-checksum-add-a-kmsan-check.patch
s390-cpacf-unpoison-the-results-of-cpacf_trng.patch
s390-cpumf-unpoison-stcctm-output-buffer.patch
s390-diag-unpoison-diag224-output-buffer.patch
s390-ftrace-unpoison-ftrace_regs-in-kprobe_ftrace_handler.patch
s390-irqflags-do-not-instrument-arch_local_irq_-with-kmsan.patch
s390-mm-define-kmsan-metadata-for-vmalloc-and-modules.patch
s390-string-add-kmsan-support.patch
s390-traps-unpoison-the-kernel_stack_overflows-pt_regs.patch
s390-uaccess-add-kmsan-support-to-put_user-and-get_user.patch
s390-uaccess-add-the-missing-linux-instrumentedh-include.patch
s390-unwind-disable-kmsan-checks.patch
s390-kmsan-implement-the-architecture-specific-functions.patch
kmsan-enable-on-s390.patch

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