count stray interrupts, fpe traps; add alignment support code (must

go back and correct stack offsets for extra registers saved?)

SCCS-vsn: sys/tahoe/tahoe/locore.s 1.9

diff --git a/usr/src/sys/tahoe/tahoe/locore.s b/usr/src/sys/tahoe/tahoe/locore.s
index 4e19de0..73fed04 100644 (file)
--- a/usr/src/sys/tahoe/tahoe/locore.s
+++ b/usr/src/sys/tahoe/tahoe/locore.s
@@ -1,4 +1,4 @@
-/*     locore.s        1.8     86/07/16        */
+/*     locore.s        1.9     86/07/20        */

 
 #include "../tahoe/mtpr.h"
 #include "../tahoe/trap.h"
 
 #include "../tahoe/mtpr.h"
 #include "../tahoe/trap.h"


@@ -311,6 +311,7 @@ SCBVEC(powfail):                    # We should be on interrupt stack now.
        halt
 
 SCBVEC(stray):
        halt
 
 SCBVEC(stray):

+       incl    _cnt+V_INTR             # add to statistics

        rei
 
 #include "../net/netisr.h"
        rei
 
 #include "../net/netisr.h"


@@ -494,8 +495,16 @@ SCBVEC(tracep):
        pushl $0;
        SAVE_FPSTAT(8)
        TRAP(TRCTRAP)
        pushl $0;
        SAVE_FPSTAT(8)
        TRAP(TRCTRAP)

+#include "align.h"

 SCBVEC(alignflt):
 SCBVEC(alignflt):

+#if NALIGN > 0
+       bitl    $PSL_CURMOD,4(sp)
+       jeql    align_excp              # Can't emulate for kernel mode !
+       jbr     non_aligned             # Only emulated for user mode.
+align_excp:
+#else

        CHECK_SFE(4)
        CHECK_SFE(4)

+#endif

        pushl $0;
        SAVE_FPSTAT(8)
        TRAP(ALIGNFLT)
        pushl $0;
        SAVE_FPSTAT(8)
        TRAP(ALIGNFLT)


@@ -517,6 +526,7 @@ segflt:
 SCBVEC(fpm):                   # Floating Point Emulation
        CHECK_SFE(16)
        SAVE_FPSTAT(16)
 SCBVEC(fpm):                   # Floating Point Emulation
        CHECK_SFE(16)
        SAVE_FPSTAT(16)

+       incl    _cnt+V_FPE      # count emulation traps

        callf   $4,_fpemulate
        REST_FPSTAT
        moval   8(sp),sp        # Pop operand
        callf   $4,_fpemulate
        REST_FPSTAT
        moval   8(sp),sp        # Pop operand


@@ -1574,3 +1584,92 @@ ENTRY(locc, 0)
 2:
        subl3   r0,r1,r0; ret           # return (end - cp);
 #endif
 2:
        subl3   r0,r1,r0; ret           # return (end - cp);
 #endif

+
+#if NALIGN > 0
+
+#include "../tahoealign/align.h"
+
+       .globl  _alignment
+/*
+ * There's an intimate relationship between this piece of code
+ * and the alignment emulation code (especially the layout
+ * of local variables in alignment.c! Don't change unless
+ * you update both this, alignment.h and alignment.c !!
+ */
+non_aligned:
+       orb2    $EMULATEALIGN,_u+U_EOSYS
+       incl    _cnt+V_TRAP
+       incl    _cnt+V_ALIGN            # count emulated alignment traps
+       moval   4(sp),_user_psl
+       SAVE_FPSTAT(4)                  # Also zeroes out ret_exception !
+       pushl   $0                      # ret_addr
+       pushl   $0                      # ret_code
+       mfpr    $USP,-(sp)              # user sp
+       callf   $4,_alignment           # call w/o parms so regs may be modified
+       /*
+        * We return here after a successful emulation or an exception.
+        * The registers have been restored and we must not alter them
+        * before returning to the user.
+        */
+2:     mtpr    (sp)+,$USP              # restore user sp
+       tstl    8(sp)                   # Any exception ?
+       bneq    got_excp                # Yes, reflect it back to user.
+       moval   8(sp),sp                # pop 2 zeroes pushed above
+       REST_FPSTAT
+       xorb2   $EMULATEALIGN,_u+U_EOSYS
+
+       bitl    $PSL_T,4(sp)            # check for trace bit set
+       beql    9f
+       CHECK_SFE(4)
+       pushl $0
+       SAVE_FPSTAT(8)
+       TRAP(TRCTRAP)
+9:     rei
+
+got_excp:                              # decode exception
+       casel   8(sp),$ILL_ADDRMOD,$ALIGNMENT
+       .align  1
+L1:
+       .word   ill_addrmod-L1
+       .word   ill_access-L1
+       .word   ill_oprnd-L1
+       .word   arithmetic-L1
+       .word   alignment-L1
+       brw     alignment               # default - shouldn't come here at all !
+
+ill_addrmod:                           # No other parameters. Set up stack as
+       moval   8(sp),sp                # the HW would do it in a real case.
+       REST_FPSTAT
+       jbr     _Xresadflt
+ill_oprnd:
+       moval   8(sp),sp
+       REST_FPSTAT
+       jbr     _Xresopflt
+alignment:
+       moval   8(sp),sp
+       REST_FPSTAT
+       jbr     align_excp      # NB: going to _Xalignflt would cause loop
+ill_access:
+       /*
+        * Must restore accumulator w/o modifying sp and w/o using
+        * registers.  Solution: copy things needed by REST_FPSTAT.
+        */
+       pushl   20(sp)                  # The flags longword
+       pushl   20(sp)                  # acc_low
+       pushl   20(sp)                  # acc_high
+       pushl   20(sp)                  # ret_exception ignored by REST_FPSTAT 
+       REST_FPSTAT                     # Back where we were with the sp !
+       movl    (sp),16(sp)             # code for illegal access
+       movl    4(sp),20(sp)            # original virtual address
+       moval   16(sp),sp               # Just like the HW would set it up
+       jbr     _Xprotflt
+arithmetic:                            # same trickery as above
+       pushl   20(sp)                  # The flags longword
+       pushl   20(sp)                  # acc_low
+       pushl   20(sp)                  # acc_high
+       pushl   20(sp)                  # ret_exception ignored by REST_FPSTAT 
+       REST_FPSTAT                     # Back where we were with the sp !
+       movl    (sp),20(sp)             # code for arithmetic exception
+       moval   20(sp),sp               # Just like the HW would set it up
+       jbr     _Xarithtrap
+#endif