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a84eeaa96b
The MPX registers (bndcsr/bndcfgu/bndstatus) are not directly accessible via normal instructions. They essentially act as if they were floating point registers and are saved/restored along with those registers. There are two main paths in the MPX code where we care about the contents of these registers: 1. #BR (bounds) faults 2. the prctl() code where we are setting MPX up Both of those paths _might_ be called without the FPU having been used. That means that 'tsk->thread.fpu.state' might never be allocated. Also, fpu_save_init() is not preempt-safe. It was a bug to call it without disabling preemption. The new get_xsave_addr() calls unlazy_fpu() instead and properly disables preemption. Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Dave Hansen <dave@sr71.net> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Suresh Siddha <sbsiddha@gmail.com> Cc: bp@alien8.de Link: http://lkml.kernel.org/r/20150607183701.BC0D37CF@viggo.jf.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
104 lines
2.9 KiB
C
104 lines
2.9 KiB
C
#ifndef _ASM_X86_MPX_H
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#define _ASM_X86_MPX_H
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#include <linux/types.h>
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#include <asm/ptrace.h>
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#include <asm/insn.h>
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/*
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* NULL is theoretically a valid place to put the bounds
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* directory, so point this at an invalid address.
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*/
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#define MPX_INVALID_BOUNDS_DIR ((void __user *)-1)
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#define MPX_BNDCFG_ENABLE_FLAG 0x1
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#define MPX_BD_ENTRY_VALID_FLAG 0x1
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#ifdef CONFIG_X86_64
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/* upper 28 bits [47:20] of the virtual address in 64-bit used to
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* index into bounds directory (BD).
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*/
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#define MPX_BD_ENTRY_OFFSET 28
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#define MPX_BD_ENTRY_SHIFT 3
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/* bits [19:3] of the virtual address in 64-bit used to index into
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* bounds table (BT).
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*/
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#define MPX_BT_ENTRY_OFFSET 17
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#define MPX_BT_ENTRY_SHIFT 5
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#define MPX_IGN_BITS 3
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#define MPX_BD_ENTRY_TAIL 3
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#else
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#define MPX_BD_ENTRY_OFFSET 20
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#define MPX_BD_ENTRY_SHIFT 2
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#define MPX_BT_ENTRY_OFFSET 10
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#define MPX_BT_ENTRY_SHIFT 4
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#define MPX_IGN_BITS 2
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#define MPX_BD_ENTRY_TAIL 2
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#endif
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#define MPX_BD_SIZE_BYTES (1UL<<(MPX_BD_ENTRY_OFFSET+MPX_BD_ENTRY_SHIFT))
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#define MPX_BT_SIZE_BYTES (1UL<<(MPX_BT_ENTRY_OFFSET+MPX_BT_ENTRY_SHIFT))
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#define MPX_BNDSTA_TAIL 2
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#define MPX_BNDCFG_TAIL 12
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#define MPX_BNDSTA_ADDR_MASK (~((1UL<<MPX_BNDSTA_TAIL)-1))
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#define MPX_BNDCFG_ADDR_MASK (~((1UL<<MPX_BNDCFG_TAIL)-1))
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#define MPX_BT_ADDR_MASK (~((1UL<<MPX_BD_ENTRY_TAIL)-1))
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#define MPX_BNDCFG_ADDR_MASK (~((1UL<<MPX_BNDCFG_TAIL)-1))
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#define MPX_BNDSTA_ERROR_CODE 0x3
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#define MPX_BD_ENTRY_MASK ((1<<MPX_BD_ENTRY_OFFSET)-1)
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#define MPX_BT_ENTRY_MASK ((1<<MPX_BT_ENTRY_OFFSET)-1)
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#define MPX_GET_BD_ENTRY_OFFSET(addr) ((((addr)>>(MPX_BT_ENTRY_OFFSET+ \
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MPX_IGN_BITS)) & MPX_BD_ENTRY_MASK) << MPX_BD_ENTRY_SHIFT)
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#define MPX_GET_BT_ENTRY_OFFSET(addr) ((((addr)>>MPX_IGN_BITS) & \
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MPX_BT_ENTRY_MASK) << MPX_BT_ENTRY_SHIFT)
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#ifdef CONFIG_X86_INTEL_MPX
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siginfo_t *mpx_generate_siginfo(struct pt_regs *regs,
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struct task_struct *tsk);
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int mpx_handle_bd_fault(struct task_struct *tsk);
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static inline int kernel_managing_mpx_tables(struct mm_struct *mm)
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{
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return (mm->bd_addr != MPX_INVALID_BOUNDS_DIR);
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}
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static inline void mpx_mm_init(struct mm_struct *mm)
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{
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/*
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* NULL is theoretically a valid place to put the bounds
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* directory, so point this at an invalid address.
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*/
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mm->bd_addr = MPX_INVALID_BOUNDS_DIR;
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}
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void mpx_notify_unmap(struct mm_struct *mm, struct vm_area_struct *vma,
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unsigned long start, unsigned long end);
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#else
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static inline siginfo_t *mpx_generate_siginfo(struct pt_regs *regs,
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struct task_struct *tsk)
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{
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return NULL;
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}
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static inline int mpx_handle_bd_fault(struct task_struct *tsk)
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{
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return -EINVAL;
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}
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static inline int kernel_managing_mpx_tables(struct mm_struct *mm)
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{
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return 0;
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}
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static inline void mpx_mm_init(struct mm_struct *mm)
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{
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}
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static inline void mpx_notify_unmap(struct mm_struct *mm,
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struct vm_area_struct *vma,
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unsigned long start, unsigned long end)
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{
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}
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#endif /* CONFIG_X86_INTEL_MPX */
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#endif /* _ASM_X86_MPX_H */
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