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• Top-level-memory

Rme32

Read an unsigned 32-bit value from memory via an effective address.

Signature

(rme32 proc-mode 
       eff-addr seg-reg r-x check-alignment? 
       x86 &key (mem-ptr? 'nil)) 
 
  → 
(mv flg value x86-new)

Arguments

check-alignment? — Guard (booleanp check-alignment?).

mem-ptr? — Guard (booleanp mem-ptr?).

Returns

value — Type (unsigned-byte-p 32 value), given (x86p x86).

x86-new — Type (x86p x86-new), given (x86p x86).

The effective address eff-addr is translated to a canonical linear address using ea-to-la. If this translation is successful and no other errors (like alignment errors) occur, then rml32 is called.

Prior to the effective address translation, we check whether read access is allowed. The only case in which it is not allowed is when a read access is attempted on an execute-only code segment, in 32-bit mode. In 64-bit mode, the R bit of the code segment descriptor is ignored (see Atmel manual, Dec'17, Volume 2, Section 4.8.1).

Definitions and Theorems

Function: rme32$inline

(defun rme32$inline (proc-mode eff-addr seg-reg
                               r-x check-alignment? x86 mem-ptr?)
 (declare (xargs :stobjs (x86)))
 (declare (type (integer 0 4) proc-mode)
          (type (signed-byte 64) eff-addr)
          (type (integer 0 5) seg-reg)
          (type (member :r :x) r-x))
 (declare (xargs :guard (and (booleanp check-alignment?)
                             (booleanp mem-ptr?))))
 (b*
  (((when
     (and (/= proc-mode 0)
          (= seg-reg 1)
          (eq r-x :r)
          (b* ((attr (loghead 16 (seg-hidden-attri seg-reg x86)))
               (r (code-segment-descriptor-attributesbits->r attr)))
            (= r 0))))
    (mv (list :execute-only-code-segment eff-addr)
        0 x86))
   ((mv flg lin-addr)
    (ea-to-la proc-mode eff-addr seg-reg 4 x86))
   ((when flg) (mv flg 0 x86))
   ((unless (or (not check-alignment?)
                (address-aligned-p lin-addr 4 mem-ptr?)))
    (mv (list :unaligned-linear-address lin-addr)
        0 x86)))
  (rml32 lin-addr r-x x86)))

Theorem: return-type-of-rme32.value

(defthm return-type-of-rme32.value
  (implies (x86p x86)
           (b* (((mv ?flg acl2::?value ?x86-new)
                 (rme32$inline proc-mode eff-addr seg-reg
                               r-x check-alignment? x86 mem-ptr?)))
             (unsigned-byte-p 32 value)))
  :rule-classes :rewrite)

Theorem: x86p-of-rme32.x86-new

(defthm x86p-of-rme32.x86-new
  (implies (x86p x86)
           (b* (((mv ?flg acl2::?value ?x86-new)
                 (rme32$inline proc-mode eff-addr seg-reg
                               r-x check-alignment? x86 mem-ptr?)))
             (x86p x86-new)))
  :rule-classes :rewrite)

Theorem: n32p-of-mv-nth-1-rme32

(defthm n32p-of-mv-nth-1-rme32
 (unsigned-byte-p 32
                  (mv-nth 1
                          (rme32 proc-mode eff-addr
                                 seg-reg r-x check-alignment? x86
                                 :mem-ptr? mem-ptr?)))
 :rule-classes
 (:rewrite
  (:type-prescription
    :corollary (natp (mv-nth 1
                             (rme32 proc-mode eff-addr
                                    seg-reg r-x check-alignment? x86
                                    :mem-ptr? mem-ptr?)))
    :hints
    (("Goal" :in-theory '(unsigned-byte-p integer-range-p natp))))
  (:linear
   :corollary
   (and (<= 0
            (mv-nth 1
                    (rme32 proc-mode eff-addr
                           seg-reg r-x check-alignment? x86
                           :mem-ptr? mem-ptr?)))
        (< (mv-nth 1
                   (rme32 proc-mode eff-addr
                          seg-reg r-x check-alignment? x86
                          :mem-ptr? mem-ptr?))
           4294967296))
   :hints
   (("Goal"
        :in-theory '(unsigned-byte-p integer-range-p (:e expt)))))))

Theorem: rme32-value-when-error

(defthm rme32-value-when-error
  (implies (mv-nth 0
                   (rme32 proc-mode eff-addr
                          seg-reg r-x check-alignment? x86
                          :mem-ptr? mem-ptr?))
           (equal (mv-nth 1
                          (rme32 proc-mode eff-addr
                                 seg-reg r-x check-alignment? x86
                                 :mem-ptr? mem-ptr?))
                  0)))

Theorem: rme32-does-not-affect-state-in-app-view

(defthm rme32-does-not-affect-state-in-app-view
  (implies (app-view x86)
           (equal (mv-nth 2
                          (rme32 proc-mode eff-addr
                                 seg-reg r-x check-alignment? x86
                                 :mem-ptr? mem-ptr?))
                  x86)))

Theorem: xr-rme32-state-app-view

(defthm xr-rme32-state-app-view
 (implies (app-view x86)
          (equal (xr fld index
                     (mv-nth 2
                             (rme32 proc-mode eff-addr
                                    seg-reg r-x check-alignment? x86
                                    :mem-ptr? mem-ptr?)))
                 (xr fld index x86))))

Theorem: xr-rme32-state-sys-view

(defthm xr-rme32-state-sys-view
 (implies (and (not (equal fld :mem))
               (not (equal fld :fault))
               (not (equal fld :tlb)))
          (equal (xr fld index
                     (mv-nth 2
                             (rme32 proc-mode eff-addr
                                    seg-reg r-x check-alignment? x86
                                    :mem-ptr? mem-ptr?)))
                 (xr fld index x86))))

Theorem: rme32-xw-app-view

(defthm rme32-xw-app-view
 (implies
    (and (app-view x86)
         (not (equal fld :mem))
         (not (equal fld :app-view))
         (not (equal fld :seg-hidden-base))
         (not (equal fld :seg-hidden-limit))
         (not (equal fld :seg-hidden-attr))
         (not (equal fld :seg-visible))
         (not (equal fld :msr)))
    (and (equal (mv-nth 0
                        (rme32 proc-mode
                               eff-addr seg-reg r-x check-alignment?
                               (xw fld index value x86)
                               :mem-ptr? mem-ptr?))
                (mv-nth 0
                        (rme32 proc-mode eff-addr
                               seg-reg r-x check-alignment? x86
                               :mem-ptr? mem-ptr?)))
         (equal (mv-nth 1
                        (rme32 proc-mode
                               eff-addr seg-reg r-x check-alignment?
                               (xw fld index value x86)
                               :mem-ptr? mem-ptr?))
                (mv-nth 1
                        (rme32 proc-mode eff-addr
                               seg-reg r-x check-alignment? x86
                               :mem-ptr? mem-ptr?))))))

Theorem: rme32-xw-sys-view

(defthm rme32-xw-sys-view
 (implies
    (and (not (app-view x86))
         (not (equal fld :fault))
         (not (equal fld :seg-visible))
         (not (equal fld :seg-hidden-base))
         (not (equal fld :seg-hidden-limit))
         (not (equal fld :seg-hidden-attr))
         (not (equal fld :mem))
         (not (equal fld :ctr))
         (not (equal fld :msr))
         (not (equal fld :rflags))
         (not (equal fld :app-view))
         (not (equal fld :tlb))
         (not (equal fld :marking-view))
         (not (equal fld :implicit-supervisor-access))
         (member-equal fld *x86-field-names-as-keywords*))
    (and (equal (mv-nth 0
                        (rme32 proc-mode
                               eff-addr seg-reg r-x check-alignment?
                               (xw fld index value x86)
                               :mem-ptr? mem-ptr?))
                (mv-nth 0
                        (rme32 proc-mode eff-addr
                               seg-reg r-x check-alignment? x86
                               :mem-ptr? mem-ptr?)))
         (equal (mv-nth 1
                        (rme32 proc-mode
                               eff-addr seg-reg r-x check-alignment?
                               (xw fld index value x86)
                               :mem-ptr? mem-ptr?))
                (mv-nth 1
                        (rme32 proc-mode eff-addr
                               seg-reg r-x check-alignment? x86
                               :mem-ptr? mem-ptr?)))
         (equal (mv-nth 2
                        (rme32 proc-mode
                               eff-addr seg-reg r-x check-alignment?
                               (xw fld index value x86)
                               :mem-ptr? mem-ptr?))
                (xw fld index value
                    (mv-nth 2
                            (rme32 proc-mode eff-addr
                                   seg-reg r-x check-alignment? x86
                                   :mem-ptr? mem-ptr?)))))))

Theorem: rme32-xw-sys-view-rflags-not-ac

(defthm rme32-xw-sys-view-rflags-not-ac
 (implies
    (and (not (app-view x86))
         (equal (rflagsbits->ac value)
                (rflagsbits->ac (rflags x86))))
    (and (equal (mv-nth 0
                        (rme32 proc-mode
                               eff-addr seg-reg r-x check-alignment?
                               (xw :rflags nil value x86)
                               :mem-ptr? mem-ptr?))
                (mv-nth 0
                        (rme32 proc-mode eff-addr
                               seg-reg r-x check-alignment? x86
                               :mem-ptr? mem-ptr?)))
         (equal (mv-nth 1
                        (rme32 proc-mode
                               eff-addr seg-reg r-x check-alignment?
                               (xw :rflags nil value x86)
                               :mem-ptr? mem-ptr?))
                (mv-nth 1
                        (rme32 proc-mode eff-addr
                               seg-reg r-x check-alignment? x86
                               :mem-ptr? mem-ptr?)))
         (equal (mv-nth 2
                        (rme32 proc-mode
                               eff-addr seg-reg r-x check-alignment?
                               (xw :rflags nil value x86)
                               :mem-ptr? mem-ptr?))
                (xw :rflags nil value
                    (mv-nth 2
                            (rme32 proc-mode eff-addr
                                   seg-reg r-x check-alignment? x86
                                   :mem-ptr? mem-ptr?)))))))

Theorem: rme32-when-64-bit-modep-and-not-fs/gs

(defthm rme32-when-64-bit-modep-and-not-fs/gs
  (implies (and (not (equal seg-reg 4))
                (not (equal seg-reg 5))
                (canonical-address-p eff-addr)
                (or (not check-alignment?)
                    (address-aligned-p eff-addr 4 mem-ptr?)))
           (equal (rme32 0 eff-addr
                         seg-reg r-x check-alignment? x86
                         :mem-ptr? mem-ptr?)
                  (rml32 eff-addr r-x x86))))

Theorem: rme32-unaligned-when-64-bit-modep-and-not-fs/gs

(defthm rme32-unaligned-when-64-bit-modep-and-not-fs/gs
  (implies (and (not (equal seg-reg 4))
                (not (equal seg-reg 5))
                (not (or (not check-alignment?)
                         (address-aligned-p eff-addr 4 mem-ptr?)))
                (canonical-address-p eff-addr))
           (equal (rme32 0 eff-addr
                         seg-reg r-x check-alignment? x86
                         :mem-ptr? mem-ptr?)
                  (list (list :unaligned-linear-address eff-addr)
                        0 x86))))

Theorem: rme32-when-64-bit-modep-and-fs/gs

(defthm rme32-when-64-bit-modep-and-fs/gs
 (implies
  (or (equal seg-reg 4) (equal seg-reg 5))
  (equal (rme32 0 eff-addr
                seg-reg r-x check-alignment? x86
                :mem-ptr? mem-ptr?)
         (b* (((mv flg lin-addr)
               (b* (((mv base & &)
                     (segment-base-and-bounds 0 seg-reg x86))
                    (lin-addr (i64 (+ base (n64 eff-addr)))))
                 (if (canonical-address-p lin-addr)
                     (mv nil lin-addr)
                   (mv (list :non-canonical-address lin-addr)
                       0))))
              ((when flg) (mv flg 0 x86))
              ((unless (or (not check-alignment?)
                           (address-aligned-p lin-addr 4 mem-ptr?)))
               (mv (list :unaligned-linear-address lin-addr)
                   0 x86)))
           (rml32 lin-addr r-x x86)))))