54 lines
1.9 KiB
Diff
54 lines
1.9 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Maxim Levitsky <mlevitsk@redhat.com>
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Date: Wed, 3 Aug 2022 18:49:59 +0300
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Subject: [PATCH] bug: introduce ASSERT_STRUCT_OFFSET
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ASSERT_STRUCT_OFFSET allows to assert during the build of
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the kernel that a field in a struct have an expected offset.
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KVM used to have such macro, but there is almost nothing KVM specific
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in it so move it to build_bug.h, so that it can be used in other
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places in KVM.
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Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
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Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
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---
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arch/x86/kvm/vmx/vmcs12.h | 5 ++---
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include/linux/build_bug.h | 9 +++++++++
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2 files changed, 11 insertions(+), 3 deletions(-)
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diff --git a/arch/x86/kvm/vmx/vmcs12.h b/arch/x86/kvm/vmx/vmcs12.h
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index 746129ddd5ae..01936013428b 100644
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--- a/arch/x86/kvm/vmx/vmcs12.h
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+++ b/arch/x86/kvm/vmx/vmcs12.h
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@@ -208,9 +208,8 @@ struct __packed vmcs12 {
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/*
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* For save/restore compatibility, the vmcs12 field offsets must not change.
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*/
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-#define CHECK_OFFSET(field, loc) \
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- BUILD_BUG_ON_MSG(offsetof(struct vmcs12, field) != (loc), \
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- "Offset of " #field " in struct vmcs12 has changed.")
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+#define CHECK_OFFSET(field, loc) \
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+ ASSERT_STRUCT_OFFSET(struct vmcs12, field, loc)
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static inline void vmx_check_vmcs12_offsets(void)
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{
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diff --git a/include/linux/build_bug.h b/include/linux/build_bug.h
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index e3a0be2c90ad..3aa3640f8c18 100644
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--- a/include/linux/build_bug.h
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+++ b/include/linux/build_bug.h
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@@ -77,4 +77,13 @@
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#define static_assert(expr, ...) __static_assert(expr, ##__VA_ARGS__, #expr)
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#define __static_assert(expr, msg, ...) _Static_assert(expr, msg)
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+
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+/*
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+ * Compile time check that field has an expected offset
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+ */
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+#define ASSERT_STRUCT_OFFSET(type, field, expected_offset) \
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+ BUILD_BUG_ON_MSG(offsetof(type, field) != (expected_offset), \
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+ "Offset of " #field " in " #type " has changed.")
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+
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+
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#endif /* _LINUX_BUILD_BUG_H */
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