From 1126cb4535c4ff172c37a412a6bd25d6b47a1901 Mon Sep 17 00:00:00 2001 From: Dave Hansen Date: Wed, 2 Sep 2015 16:31:29 -0700 Subject: [PATCH] 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: Dave Hansen Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: Fenghua Yu Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Tim Chen 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: Ingo Molnar --- arch/x86/include/asm/fpu/types.h | 29 +++++++++++++++++++++++------ arch/x86/include/asm/trace/mpx.h | 7 ++++--- arch/x86/kernel/traps.c | 2 +- arch/x86/mm/mpx.c | 9 +++++---- 4 files changed, 33 insertions(+), 14 deletions(-) diff --git a/arch/x86/include/asm/fpu/types.h b/arch/x86/include/asm/fpu/types.h index 9f579305dd11..4d8c2009b94e 100644 --- a/arch/x86/include/asm/fpu/types.h +++ b/arch/x86/include/asm/fpu/types.h @@ -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; diff --git a/arch/x86/include/asm/trace/mpx.h b/arch/x86/include/asm/trace/mpx.h index 173dd3ba108c..0f492fc50bce 100644 --- a/arch/x86/include/asm/trace/mpx.h +++ b/arch/x86/include/asm/trace/mpx.h @@ -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) { } diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 0cd2ac5c0f28..ade185a46b1d 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -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"); diff --git a/arch/x86/mm/mpx.c b/arch/x86/mm/mpx.c index f35fc9c6ed50..b0ae85f90f10 100644 --- a/arch/x86/mm/mpx.c +++ b/arch/x86/mm/mpx.c @@ -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); -- 2.34.1