src/code/x86-vm.lisp

   1 ;;;; X86-specific runtime stuff
   2
   3 ;;;; This software is part of the SBCL system. See the README file for
   4 ;;;; more information.
   5 ;;;;
   6 ;;;; This software is derived from the CMU CL system, which was
   7 ;;;; written at Carnegie Mellon University and released into the
   8 ;;;; public domain. The software is in the public domain and is
   9 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
  10 ;;;; files for more information.
  11
  12 (in-package "SB!VM")
  13 \f
  14 ;;;; OS-CONTEXT-T
  15
  16 ;;; a POSIX signal context, i.e. the type passed as the third
  17 ;;; argument to an SA_SIGACTION-style signal handler
  18 ;;;
  19 ;;; The real type does have slots, but at Lisp level, we never
  20 ;;; access them, or care about the size of the object. Instead, we
  21 ;;; always refer to these objects by pointers handed to us by the C
  22 ;;; runtime library, and ask the runtime library any time we need
  23 ;;; information about the contents of one of these objects. Thus, it
  24 ;;; works to represent this as an object with no slots.
  25 ;;;
  26 ;;; KLUDGE: It would be nice to have a type definition analogous to
  27 ;;; C's "struct os_context_t;", for an incompletely specified object
  28 ;;; which can only be referred to by reference, but I don't know how
  29 ;;; to do that in the FFI, so instead we just this bogus no-slots
  30 ;;; representation. -- WHN 20000730
  31 ;;;
  32 ;;; FIXME: Since SBCL, unlike CMU CL, uses this as an opaque type,
  33 ;;; it's no longer architecture-dependent, and probably belongs in
  34 ;;; some other package, perhaps SB-KERNEL.
  35 (define-alien-type os-context-t (struct os-context-t-struct))
  36 \f
  37 ;;;; MACHINE-TYPE
  38
  39 (defun machine-type ()
  40   #!+sb-doc
  41   "Return a string describing the type of the local machine."
  42   "X86")
  43 \f
  44 ;;;; :CODE-OBJECT fixups
  45
  46 ;;; a counter to measure the storage overhead of these fixups
  47 (defvar *num-fixups* 0)
  48 ;;; FIXME: When the system runs, it'd be interesting to see what this is.
  49
  50 (declaim (inline adjust-fixup-array))
  51 (defun adjust-fixup-array (array size)
  52   (let ((new (make-array size :element-type '(unsigned-byte 32))))
  53     (replace new array)
  54     new))
  55
  56 ;;; This gets called by LOAD to resolve newly positioned objects
  57 ;;; with things (like code instructions) that have to refer to them.
  58 ;;;
  59 ;;; Add a fixup offset to the vector of fixup offsets for the given
  60 ;;; code object.
  61 (defun fixup-code-object (code offset fixup kind)
  62   (declare (type index offset))
  63   (flet ((add-fixup (code offset)
  64            ;; (We check for and ignore fixups for code objects in the
  65            ;; read-only and static spaces. (In the old CMU CL code
  66            ;; this check was conditional on *ENABLE-DYNAMIC-SPACE-CODE*,
  67            ;; but in SBCL relocatable dynamic space code is always in
  68            ;; use, so we always do the check.)
  69            (incf *num-fixups*)
  70            (let ((fixups (code-header-ref code code-constants-offset)))
  71              (cond ((typep fixups '(simple-array (unsigned-byte 32) (*)))
  72                     (let ((new-fixups
  73                            (adjust-fixup-array fixups (1+ (length fixups)))))
  74                       (setf (aref new-fixups (length fixups)) offset)
  75                       (setf (code-header-ref code code-constants-offset)
  76                             new-fixups)))
  77                    (t
  78                     (unless (or (eq (widetag-of fixups)
  79                                     unbound-marker-widetag)
  80                                 (zerop fixups))
  81                       (format t "** Init. code FU = ~S~%" fixups)) ; FIXME
  82                     (setf (code-header-ref code code-constants-offset)
  83                           (make-array
  84                            1
  85                            :element-type '(unsigned-byte 32)
  86                            :initial-element offset)))))))
  87     (sb!sys:without-gcing
  88      (let* ((sap (truly-the system-area-pointer
  89                             (sb!kernel:code-instructions code)))
  90             (obj-start-addr (logand (sb!kernel:get-lisp-obj-address code)
  91                                     #xfffffff8))
  92             ;; FIXME: what is this 5?
  93             #+nil (const-start-addr (+ obj-start-addr (* 5 n-word-bytes)))
  94             (code-start-addr (sb!sys:sap-int (sb!kernel:code-instructions
  95                                               code)))
  96             (ncode-words (sb!kernel:code-header-ref code 1))
  97             (code-end-addr (+ code-start-addr (* ncode-words n-word-bytes))))
  98        (unless (member kind '(:absolute :relative))
  99          (error "Unknown code-object-fixup kind ~S." kind))
 100        (ecase kind
 101          (:absolute
 102           ;; Word at sap + offset contains a value to be replaced by
 103           ;; adding that value to fixup.
 104           (setf (sap-ref-32 sap offset) (+ fixup (sap-ref-32 sap offset)))
 105           ;; Record absolute fixups that point within the code object.
 106           (when (> code-end-addr (sap-ref-32 sap offset) obj-start-addr)
 107             (add-fixup code offset)))
 108          (:relative
 109           ;; Fixup is the actual address wanted.
 110           ;;
 111           ;; Record relative fixups that point outside the code
 112           ;; object.
 113           (when (or (< fixup obj-start-addr) (> fixup code-end-addr))
 114             (add-fixup code offset))
 115           ;; Replace word with value to add to that loc to get there.
 116           (let* ((loc-sap (+ (sap-int sap) offset))
 117                  (rel-val (- fixup loc-sap n-word-bytes)))
 118             (declare (type (unsigned-byte 32) loc-sap)
 119                      (type (signed-byte 32) rel-val))
 120             (setf (signed-sap-ref-32 sap offset) rel-val))))))
 121     nil))
 122 \f
 123 ;;;; low-level signal context access functions
 124 ;;;;
 125 ;;;; Note: In CMU CL, similar functions were hardwired to access
 126 ;;;; BSD-style sigcontext structures defined as alien objects. Our
 127 ;;;; approach is different in two ways:
 128 ;;;;   1. We use POSIX SA_SIGACTION-style signals, so our context is
 129 ;;;;      whatever the void pointer in the sigaction handler dereferences
 130 ;;;;      to, not necessarily a sigcontext.
 131 ;;;;   2. We don't try to maintain alien definitions of the context
 132 ;;;;      structure at Lisp level, but instead call alien C functions
 133 ;;;;      which take care of access for us. (Since the C functions can
 134 ;;;;      be defined in terms of system standard header files, they
 135 ;;;;      should be easier to maintain; and since Lisp code uses signal
 136 ;;;;      contexts only in interactive or exception code (like the debugger
 137 ;;;;      and internal error handling) the extra runtime cost should be
 138 ;;;;      negligible.
 139
 140 (declaim (inline context-pc-addr))
 141 (define-alien-routine ("os_context_pc_addr" context-pc-addr) (* unsigned-int)
 142   ;; (Note: Just as in CONTEXT-REGISTER-ADDR, we intentionally use an
 143   ;; 'unsigned *' interpretation for the 32-bit word passed to us by
 144   ;; the C code, even though the C code may think it's an 'int *'.)
 145   (context (* os-context-t)))
 146
 147 (declaim (inline context-pc))
 148 (defun context-pc (context)
 149   (declare (type (alien (* os-context-t)) context))
 150   (let ((addr (context-pc-addr context)))
 151     (declare (type (alien (* unsigned-int)) addr))
 152     (int-sap (deref addr))))
 153
 154 (declaim (inline context-register-addr))
 155 (define-alien-routine ("os_context_register_addr" context-register-addr)
 156   (* unsigned-int)
 157   ;; (Note the mismatch here between the 'int *' value that the C code
 158   ;; may think it's giving us and the 'unsigned *' value that we
 159   ;; receive. It's intentional: the C header files may think of
 160   ;; register values as signed, but the CMU CL code tends to think of
 161   ;; register values as unsigned, and might get bewildered if we ask
 162   ;; it to work with signed values.)
 163   (context (* os-context-t))
 164   (index int))
 165
 166 (declaim (inline context-register))
 167 (defun context-register (context index)
 168   (declare (type (alien (* os-context-t)) context))
 169   (let ((addr (context-register-addr context index)))
 170     (declare (type (alien (* unsigned-int)) addr))
 171     (deref addr)))
 172
 173 (defun %set-context-register (context index new)
 174   (declare (type (alien (* os-context-t)) context))
 175   (let ((addr (context-register-addr context index)))
 176     (declare (type (alien (* unsigned-int)) addr))
 177     (setf (deref addr) new)))
 178
 179 ;;; This is like CONTEXT-REGISTER, but returns the value of a float
 180 ;;; register. FORMAT is the type of float to return.
 181 ;;;
 182 ;;; As of sbcl-0.6.7, there is no working code which calls this code,
 183 ;;; so it's stubbed out. Someday, in order to make the debugger work
 184 ;;; better, it may be necessary to unstubify it.
 185 (defun context-float-register (context index format)
 186   (declare (ignore context index))
 187   (warn "stub CONTEXT-FLOAT-REGISTER")
 188   (coerce 0.0 format))
 189 (defun %set-context-float-register (context index format new-value)
 190   (declare (ignore context index))
 191   (warn "stub %SET-CONTEXT-FLOAT-REGISTER")
 192   (coerce new-value format))
 193
 194 ;;; Given a signal context, return the floating point modes word in
 195 ;;; the same format as returned by FLOATING-POINT-MODES.
 196 #!-(or linux sunos)
 197 (defun context-floating-point-modes (context)
 198   ;; FIXME: As of sbcl-0.6.7 and the big rewrite of signal handling for
 199   ;; POSIXness and (at the Lisp level) opaque signal contexts,
 200   ;; this is stubified. It needs to be rewritten as an
 201   ;; alien function.
 202   (declare (ignore context)) ; stub!
 203   (warn "stub CONTEXT-FLOATING-POINT-MODES")
 204   0)
 205
 206 #!+(or linux sunos)
 207 (define-alien-routine ("os_context_fp_control" context-floating-point-modes)
 208     (sb!alien:unsigned 32)
 209   (context (* os-context-t)))
 210 \f
 211 ;;;; INTERNAL-ERROR-ARGS
 212
 213 ;;; Given a (POSIX) signal context, extract the internal error
 214 ;;; arguments from the instruction stream.
 215 (defun internal-error-args (context)
 216   (declare (type (alien (* os-context-t)) context))
 217   (/show0 "entering INTERNAL-ERROR-ARGS, CONTEXT=..")
 218   (/hexstr context)
 219   (let ((pc (context-pc context)))
 220     (declare (type system-area-pointer pc))
 221     (/show0 "got PC")
 222     ;; using INT3 the pc is .. INT3 <here> code length bytes...
 223     (let* ((length (sap-ref-8 pc 1))
 224            (vector (make-array length :element-type '(unsigned-byte 8))))
 225       (declare (type (unsigned-byte 8) length)
 226                (type (simple-array (unsigned-byte 8) (*)) vector))
 227       (/show0 "LENGTH,VECTOR,ERROR-NUMBER=..")
 228       (/hexstr length)
 229       (/hexstr vector)
 230       (copy-ub8-from-system-area pc 2 vector 0 length)
 231       (let* ((index 0)
 232              (error-number (sb!c:read-var-integer vector index)))
 233         (/hexstr error-number)
 234         (collect ((sc-offsets))
 235           (loop
 236            (/show0 "INDEX=..")
 237            (/hexstr index)
 238            (when (>= index length)
 239              (return))
 240            (let ((sc-offset (sb!c:read-var-integer vector index)))
 241              (/show0 "SC-OFFSET=..")
 242              (/hexstr sc-offset)
 243              (sc-offsets sc-offset)))
 244           (values error-number (sc-offsets)))))))
 245 \f
 246 ;;; This is used in error.lisp to insure that floating-point exceptions
 247 ;;; are properly trapped. The compiler translates this to a VOP.
 248 (defun float-wait ()
 249   (float-wait))
 250
 251 ;;; float constants
 252 ;;;
 253 ;;; These are used by the FP MOVE-FROM-{SINGLE|DOUBLE} VOPs rather
 254 ;;; than the i387 load constant instructions to avoid consing in some
 255 ;;; cases. Note these are initialized by GENESIS as they are needed
 256 ;;; early.
 257 (defvar *fp-constant-0f0*)
 258 (defvar *fp-constant-1f0*)
 259 (defvar *fp-constant-0d0*)
 260 (defvar *fp-constant-1d0*)
 261 ;;; the long-float constants
 262 (defvar *fp-constant-0l0*)
 263 (defvar *fp-constant-1l0*)
 264 (defvar *fp-constant-pi*)
 265 (defvar *fp-constant-l2t*)
 266 (defvar *fp-constant-l2e*)
 267 (defvar *fp-constant-lg2*)
 268 (defvar *fp-constant-ln2*)
 269
 270 ;;; the current alien stack pointer; saved/restored for non-local exits
 271 (defvar *alien-stack*)
 272
 273 ;;; Support for the MT19937 random number generator. The update
 274 ;;; function is implemented as an assembly routine. This definition is
 275 ;;; transformed to a call to the assembly routine allowing its use in
 276 ;;; interpreted code.
 277 (defun random-mt19937 (state)
 278   (declare (type (simple-array (unsigned-byte 32) (627)) state))
 279   (random-mt19937 state))