src/code/x86-64-vm.lisp

   1 ;;;; X86-64-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 and MACHINE-VERSION
  38
  39 (defun machine-type ()
  40   #!+sb-doc
  41   "Return a string describing the type of the local machine."
  42   "X86-64")
  43
  44 ;;; arch-specific support for CL:MACHINE-VERSION, defined OAOO elsewhere
  45 (defun get-machine-version ()
  46   #!+linux
  47   (with-open-file (stream "/proc/cpuinfo"
  48                           ;; Even on Linux it's an option to build
  49                           ;; kernels without /proc filesystems, so
  50                           ;; degrade gracefully.
  51                           :if-does-not-exist nil)
  52     (loop with line while (setf line (read-line stream nil))
  53           ;; The field "model name" exists on kernel 2.4.21-rc6-ac1
  54           ;; anyway, with values e.g.
  55           ;;   "AMD Athlon(TM) XP 2000+"
  56           ;;   "Intel(R) Pentium(R) M processor 1300MHz"
  57           ;; which seem comparable to the information in the example
  58           ;; in the MACHINE-VERSION page of the ANSI spec.
  59           when (eql (search "model name" line) 0)
  60           return (string-trim " " (subseq line (1+ (position #\: line))))))
  61   #!-linux
  62   nil)
  63 \f
  64 ;;;; :CODE-OBJECT fixups
  65
  66 ;;; This gets called by LOAD to resolve newly positioned objects
  67 ;;; with things (like code instructions) that have to refer to them.
  68 (defun fixup-code-object (code offset fixup kind)
  69   (declare (type index offset))
  70   (sb!sys:without-gcing
  71     (let ((sap (truly-the system-area-pointer
  72                           (sb!kernel:code-instructions code))))
  73       (unless (member kind '(:absolute :absolute64 :relative))
  74         (error "Unknown code-object-fixup kind ~S." kind))
  75       (ecase kind
  76         (:absolute64
  77          ;; Word at sap + offset contains a value to be replaced by
  78          ;; adding that value to fixup.
  79          (setf (sap-ref-64 sap offset) (+ fixup (sap-ref-64 sap offset))))
  80         (:absolute
  81          ;; Word at sap + offset contains a value to be replaced by
  82          ;; adding that value to fixup.
  83          (setf (sap-ref-32 sap offset) (+ fixup (sap-ref-32 sap offset))))
  84         (:relative
  85          ;; Fixup is the actual address wanted.
  86          ;; Replace word with value to add to that loc to get there.
  87          (let* ((loc-sap (+ (sap-int sap) offset))
  88                 (rel-val (- fixup loc-sap (/ n-word-bytes 2))))
  89            (declare (type (unsigned-byte 64) loc-sap)
  90                     (type (signed-byte 32) rel-val))
  91            (setf (signed-sap-ref-32 sap offset) rel-val))))))
  92     nil)
  93 \f
  94 ;;;; low-level signal context access functions
  95 ;;;;
  96 ;;;; Note: In CMU CL, similar functions were hardwired to access
  97 ;;;; BSD-style sigcontext structures defined as alien objects. Our
  98 ;;;; approach is different in two ways:
  99 ;;;;   1. We use POSIX SA_SIGACTION-style signals, so our context is
 100 ;;;;      whatever the void pointer in the sigaction handler dereferences
 101 ;;;;      to, not necessarily a sigcontext.
 102 ;;;;   2. We don't try to maintain alien definitions of the context
 103 ;;;;      structure at Lisp level, but instead call alien C functions
 104 ;;;;      which take care of access for us. (Since the C functions can
 105 ;;;;      be defined in terms of system standard header files, they
 106 ;;;;      should be easier to maintain; and since Lisp code uses signal
 107 ;;;;      contexts only in interactive or exception code (like the debugger
 108 ;;;;      and internal error handling) the extra runtime cost should be
 109 ;;;;      negligible.
 110
 111 (declaim (inline context-pc-addr))
 112 (define-alien-routine ("os_context_pc_addr" context-pc-addr) (* unsigned-long)
 113   ;; (Note: Just as in CONTEXT-REGISTER-ADDR, we intentionally use an
 114   ;; 'unsigned *' interpretation for the 32-bit word passed to us by
 115   ;; the C code, even though the C code may think it's an 'int *'.)
 116   (context (* os-context-t)))
 117
 118 (declaim (inline context-pc))
 119 (defun context-pc (context)
 120   (declare (type (alien (* os-context-t)) context))
 121   (let ((addr (context-pc-addr context)))
 122     (declare (type (alien (* unsigned-long)) addr))
 123     (int-sap (deref addr))))
 124
 125 (declaim (inline context-register-addr))
 126 (define-alien-routine ("os_context_register_addr" context-register-addr)
 127   (* unsigned-long)
 128   ;; (Note the mismatch here between the 'int *' value that the C code
 129   ;; may think it's giving us and the 'unsigned *' value that we
 130   ;; receive. It's intentional: the C header files may think of
 131   ;; register values as signed, but the CMU CL code tends to think of
 132   ;; register values as unsigned, and might get bewildered if we ask
 133   ;; it to work with signed values.)
 134   (context (* os-context-t))
 135   (index int))
 136
 137 (declaim (inline context-register))
 138 (defun context-register (context index)
 139   (declare (type (alien (* os-context-t)) context))
 140   (let ((addr (context-register-addr context index)))
 141     (declare (type (alien (* unsigned-long)) addr))
 142     (deref addr)))
 143
 144 (defun %set-context-register (context index new)
 145   (declare (type (alien (* os-context-t)) context))
 146   (let ((addr (context-register-addr context index)))
 147     (declare (type (alien (* unsigned-long)) addr))
 148     (setf (deref addr) new)))
 149
 150 ;;; This is like CONTEXT-REGISTER, but returns the value of a float
 151 ;;; register. FORMAT is the type of float to return.
 152 ;;;
 153 ;;; As of sbcl-0.6.7, there is no working code which calls this code,
 154 ;;; so it's stubbed out. Someday, in order to make the debugger work
 155 ;;; better, it may be necessary to unstubify it.
 156 (defun context-float-register (context index format)
 157   (declare (ignore context index))
 158   (warn "stub CONTEXT-FLOAT-REGISTER")
 159   (coerce 0.0 format))
 160 (defun %set-context-float-register (context index format new-value)
 161   (declare (ignore context index))
 162   (warn "stub %SET-CONTEXT-FLOAT-REGISTER")
 163   (coerce new-value format))
 164
 165 ;;; Given a signal context, return the floating point modes word in
 166 ;;; the same format as returned by FLOATING-POINT-MODES.
 167 #!-linux
 168 (defun context-floating-point-modes (context)
 169   (declare (ignore context)) ; stub!
 170   (warn "stub CONTEXT-FLOATING-POINT-MODES")
 171   0)
 172 #!+linux
 173 (define-alien-routine ("os_context_fp_control" context-floating-point-modes)
 174     (sb!alien:unsigned 32)
 175   (context (* os-context-t)))
 176
 177 (define-alien-routine
 178     ("arch_get_fp_modes" floating-point-modes) (sb!alien:unsigned 32))
 179
 180 (define-alien-routine
 181     ("arch_set_fp_modes" %floating-point-modes-setter) void (fp (sb!alien:unsigned 32)))
 182
 183 (defun (setf floating-point-modes) (val) (%floating-point-modes-setter val))
 184
 185 \f
 186 ;;;; INTERNAL-ERROR-ARGS
 187
 188 ;;; Given a (POSIX) signal context, extract the internal error
 189 ;;; arguments from the instruction stream.
 190 (defun internal-error-args (context)
 191   (declare (type (alien (* os-context-t)) context))
 192   (/show0 "entering INTERNAL-ERROR-ARGS, CONTEXT=..")
 193   (/hexstr context)
 194   (let ((pc (context-pc context)))
 195     (declare (type system-area-pointer pc))
 196     (/show0 "got PC")
 197     ;; using INT3 the pc is .. INT3 <here> code length bytes...
 198     (let* ((length (sap-ref-8 pc 1))
 199            (vector (make-array length :element-type '(unsigned-byte 8))))
 200       (declare (type (unsigned-byte 8) length)
 201                (type (simple-array (unsigned-byte 8) (*)) vector))
 202       (/show0 "LENGTH,VECTOR,ERROR-NUMBER=..")
 203       (/hexstr length)
 204       (/hexstr vector)
 205       (copy-ub8-from-system-area pc 2 vector 0 length)
 206       (let* ((index 0)
 207              (error-number (sb!c:read-var-integer vector index)))
 208         (/hexstr error-number)
 209         (collect ((sc-offsets))
 210           (loop
 211            (/show0 "INDEX=..")
 212            (/hexstr index)
 213            (when (>= index length)
 214              (return))
 215            (let ((sc-offset (sb!c:read-var-integer vector index)))
 216              (/show0 "SC-OFFSET=..")
 217              (/hexstr sc-offset)
 218              (sc-offsets sc-offset)))
 219           (values error-number (sc-offsets)))))))
 220 \f
 221
 222 ;;; the current alien stack pointer; saved/restored for non-local exits
 223 (defvar *alien-stack*)