Commit 1126cb45 authored by Dave Hansen's avatar Dave Hansen Committed by Ingo Molnar
Browse files

x86/fpu/mpx: Rework MPX 'xstate' types 



MPX includes two separate "extended state components".  There is
no real need to have an 'mpx_struct' because we never really
manage the states together.

We also separate out the actual data in 'mpx_bndcsr_state' from
the padding.  We will shortly be checking the state sizes
against our structures and need them to match.  For consistency,
we also ensure to prefix these types with 'mpx_'.

Lastly, we add some comments to mirror some of the descriptions
in the Intel documents (SDM) of the various state components.

Signed-off-by: default avatarDave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: dave@sr71.net
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/20150902233129.384B73EB@viggo.jf.intel.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 633d54c4

arch/x86/include/asm/fpu/types.h

+23 −6
Original line number Diff line number Diff line
@@ -141,20 +141,37 @@ struct ymmh_struct { 
};



/* Intel MPX support: */

struct bndreg {



struct mpx_bndreg {

	u64				lower_bound;

	u64				upper_bound;

} __packed;

/*

 * State component 3 is used for the 4 128-bit bounds registers

 */

struct mpx_bndreg_state {

	struct mpx_bndreg		bndreg[4];

} __packed;



struct bndcsr {

/*

 * State component 4 is used for the 64-bit user-mode MPX

 * configuration register BNDCFGU and the 64-bit MPX status

 * register BNDSTATUS.  We call the pair "BNDCSR".

 */

struct mpx_bndcsr {

	u64				bndcfgu;

	u64				bndstatus;

} __packed;



struct mpx_struct {

	struct bndreg			bndreg[4];

	struct bndcsr			bndcsr;

/*

 * The BNDCSR state is padded out to be 64-bytes in size.

 */

struct mpx_bndcsr_state {

	union {

		struct mpx_bndcsr		bndcsr;

		u8				pad_to_64_bytes[64];

	};

} __packed;



struct xstate_header {

	u64				xfeatures;

arch/x86/include/asm/trace/mpx.h

+4 −3
Original line number Diff line number Diff line
@@ -11,7 +11,7 @@ 
TRACE_EVENT(mpx_bounds_register_exception,



	TP_PROTO(void *addr_referenced,

		 const struct bndreg *bndreg),

		 const struct mpx_bndreg *bndreg),

	TP_ARGS(addr_referenced, bndreg),



	TP_STRUCT__entry(
@@ -44,7 +44,7 @@ TRACE_EVENT(mpx_bounds_register_exception, 


TRACE_EVENT(bounds_exception_mpx,



	TP_PROTO(const struct bndcsr *bndcsr),

	TP_PROTO(const struct mpx_bndcsr *bndcsr),

	TP_ARGS(bndcsr),



	TP_STRUCT__entry(
@@ -116,7 +116,8 @@ TRACE_EVENT(mpx_new_bounds_table, 
/*

 * This gets used outside of MPX-specific code, so we need a stub.

 */

static inline void trace_bounds_exception_mpx(const struct bndcsr *bndcsr)

static inline

void trace_bounds_exception_mpx(const struct mpx_bndcsr *bndcsr)

{

}

arch/x86/kernel/traps.c

+1 −1
Original line number Diff line number Diff line
@@ -361,7 +361,7 @@ dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code) 


dotraplinkage void do_bounds(struct pt_regs *regs, long error_code)

{

	const struct bndcsr *bndcsr;

	const struct mpx_bndcsr *bndcsr;

	siginfo_t *info;



	RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");

arch/x86/mm/mpx.c

+5 −4
Original line number Diff line number Diff line
@@ -237,7 +237,8 @@ bad_opcode: 
 */

siginfo_t *mpx_generate_siginfo(struct pt_regs *regs)

{

	const struct bndreg *bndregs, *bndreg;

	const struct mpx_bndreg_state *bndregs;

	const struct mpx_bndreg *bndreg;

	siginfo_t *info = NULL;

	struct insn insn;

	uint8_t bndregno;
@@ -264,7 +265,7 @@ siginfo_t *mpx_generate_siginfo(struct pt_regs *regs) 
		goto err_out;

	}

	/* now go select the individual register in the set of 4 */

	bndreg = &bndregs[bndregno];

	bndreg = &bndregs->bndreg[bndregno];



	info = kzalloc(sizeof(*info), GFP_KERNEL);

	if (!info) {
@@ -306,7 +307,7 @@ err_out: 


static __user void *mpx_get_bounds_dir(void)

{

	const struct bndcsr *bndcsr;

	const struct mpx_bndcsr *bndcsr;



	if (!cpu_feature_enabled(X86_FEATURE_MPX))

		return MPX_INVALID_BOUNDS_DIR;
@@ -489,7 +490,7 @@ out_unmap: 
static int do_mpx_bt_fault(void)

{

	unsigned long bd_entry, bd_base;

	const struct bndcsr *bndcsr;

	const struct mpx_bndcsr *bndcsr;

	struct mm_struct *mm = current->mm;



	bndcsr = get_xsave_field_ptr(XFEATURE_MASK_BNDCSR);

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