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authorAndy Lutomirski <luto@kernel.org>2017-12-04 15:07:19 +0100
committerIngo Molnar <mingo@kernel.org>2017-12-17 13:59:56 +0100
commit1a935bc3d4ea61556461a9e92a68ca3556232efd (patch)
tree149d9019a18e78c7a004d44c2c368923043c38ce /arch/x86/include/asm/processor.h
parent6e60e583426c2f8751c22c2dfe5c207083b4483a (diff)
downloadlwn-1a935bc3d4ea61556461a9e92a68ca3556232efd.tar.gz
lwn-1a935bc3d4ea61556461a9e92a68ca3556232efd.zip
x86/entry: Move SYSENTER_stack to the beginning of struct tss_struct
SYSENTER_stack should have reliable overflow detection, which means that it needs to be at the bottom of a page, not the top. Move it to the beginning of struct tss_struct and page-align it. Also add an assertion to make sure that the fixed hardware TSS doesn't cross a page boundary. Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bpetkov@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Laight <David.Laight@aculab.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Eduardo Valentin <eduval@amazon.com> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Will Deacon <will.deacon@arm.com> Cc: aliguori@amazon.com Cc: daniel.gruss@iaik.tugraz.at Cc: hughd@google.com Cc: keescook@google.com Link: https://lkml.kernel.org/r/20171204150605.881827433@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/include/asm/processor.h')
-rw-r--r--arch/x86/include/asm/processor.h21
1 files changed, 12 insertions, 9 deletions
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 555c9478f3df..759051251664 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -332,7 +332,16 @@ struct x86_hw_tss {
struct tss_struct {
/*
- * The hardware state:
+ * Space for the temporary SYSENTER stack, used for SYSENTER
+ * and the entry trampoline as well.
+ */
+ unsigned long SYSENTER_stack_canary;
+ unsigned long SYSENTER_stack[64];
+
+ /*
+ * The fixed hardware portion. This must not cross a page boundary
+ * at risk of violating the SDM's advice and potentially triggering
+ * errata.
*/
struct x86_hw_tss x86_tss;
@@ -343,15 +352,9 @@ struct tss_struct {
* be within the limit.
*/
unsigned long io_bitmap[IO_BITMAP_LONGS + 1];
+} __aligned(PAGE_SIZE);
- /*
- * Space for the temporary SYSENTER stack.
- */
- unsigned long SYSENTER_stack_canary;
- unsigned long SYSENTER_stack[64];
-} ____cacheline_aligned;
-
-DECLARE_PER_CPU_SHARED_ALIGNED(struct tss_struct, cpu_tss);
+DECLARE_PER_CPU_PAGE_ALIGNED(struct tss_struct, cpu_tss);
/*
* sizeof(unsigned long) coming from an extra "long" at the end