[PATCH 201/208] x86/fpu: Clean up xstate feature reservation

From: Ingo Molnar
Date: Tue May 05 2015 - 14:01:31 EST


Put MPX support into its separate high level structure, and
also replace the fixed YMM, LWP and MPX structures in
xregs_state with just reservations - their exact offsets
in the structure will depend on the CPU and no code actually
relies on those fields.

No change in functionality.

Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Fenghua Yu <fenghua.yu@xxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/include/asm/fpu/types.h | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/fpu/types.h b/arch/x86/include/asm/fpu/types.h
index 4c4eceb08a42..02241c2a10e9 100644
--- a/arch/x86/include/asm/fpu/types.h
+++ b/arch/x86/include/asm/fpu/types.h
@@ -145,12 +145,21 @@ struct bndcsr {
u64 bndstatus;
} __packed;

+struct mpx_struct {
+ struct bndreg bndreg[4];
+ struct bndcsr bndcsr;
+};
+
struct xstate_header {
u64 xfeatures;
u64 xcomp_bv;
u64 reserved[6];
} __attribute__((packed));

+/* New processor state extensions should be added here: */
+#define XSTATE_RESERVE (sizeof(struct ymmh_struct) + \
+ sizeof(struct lwp_struct) + \
+ sizeof(struct mpx_struct) )
/*
* This is our most modern FPU state format, as saved by the XSAVE
* and restored by the XRSTOR instructions.
@@ -162,11 +171,7 @@ struct xstate_header {
struct xregs_state {
struct fxregs_state i387;
struct xstate_header header;
- struct ymmh_struct ymmh;
- struct lwp_struct lwp;
- struct bndreg bndreg[4];
- struct bndcsr bndcsr;
- /* New processor state extensions will go here. */
+ u8 __reserved[XSTATE_RESERVE];
} __attribute__ ((packed, aligned (64)));

/*
--
2.1.0

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