mtx: clean up caching of page state

map_restore restored the map but not the cache of the write only port, this
then caused crashes if interrupt returns occurred during a user memory
access.

Use the helpers throughout for neatness

diff --git a/Kernel/platform-mtx/mtx.s b/Kernel/platform-mtx/mtx.s
index fd943fa..f4aa211 100644 (file)
--- a/Kernel/platform-mtx/mtx.s
+++ b/Kernel/platform-mtx/mtx.s
@@ -14,6 +14,7 @@
 
            .globl map_kernel
            .globl map_process
+           .globl map_process_a
            .globl map_process_always
            .globl map_save
            .globl map_restore
@@ -226,6 +227,7 @@ map_process_a:
 map_process_always:
            push af
            ld a, (U_DATA__U_PAGE)
+map_set_a:
            ld (map_copy), a
            out (0), a
            pop af
@@ -239,9 +241,8 @@ map_save:
 map_restore:
            push af
            ld a, (map_store)
-           out (0), a
-           pop af
-           ret     
+           jr map_set_a
+
 map_store:
            .db 0
 map_copy:

diff --git a/Kernel/platform-mtx/tricks.s b/Kernel/platform-mtx/tricks.s
index afeb1ab..e9359d2 100644 (file)
--- a/Kernel/platform-mtx/tricks.s
+++ b/Kernel/platform-mtx/tricks.s
@@ -1,6 +1,5 @@
 ;
-;      This is heavily based on the Z80Pack platform code. Only the
-; constants have changed.
+;      This is heavily based on the Z80Pack platform code.
 ;
         .module tricks
 
@@ -21,6 +20,11 @@
         .globl dispatch_process_signal
        .globl _swapper
 
+       .globl map_kernel
+       .globl map_process
+       .globl map_process_a
+       .globl map_process_always
+
         ; imported debug symbols
         .globl outstring, outde, outhl, outbc, outnewline, outchar, outcharhex
 
@@ -54,14 +58,12 @@ _switchout:
 
        ; Stash the uarea back into process memory
        ld hl, (U_DATA__U_PAGE)
-       ld a, l
-       out (0), a
+       call map_process_always
        ld hl, #U_DATA
        ld de, #U_DATA_STASH
        ld bc, #U_DATA__TOTALSIZE
        ldir
-       ld a, #0x80             ; kernel
-       out (0), a
+       call map_kernel
 
         ; find another process to run (may select this one again)
         call _getproc
@@ -87,8 +89,7 @@ _switchin:
         push de ; restore stack
         push bc ; restore stack
 
-       ld a, #0x80
-       out (0), a      ; kernel
+       call map_kernel
 
        push de
         ld hl, #P_TAB__P_PAGE_OFFSET
@@ -111,10 +112,9 @@ _switchin:
        pop de
        pop hl
        ld a, (hl)
-
 not_swapped:
        ; Pages please !
-       out (0), a
+       call map_process_a
 
         ; bear in mind that the stack will be switched now, so we can't use it
        ; to carry values over this point
@@ -126,8 +126,7 @@ not_swapped:
        ldir
        exx
 
-       ld a, #0x80             ; kernel back please
-       out (0), a
+       call map_kernel
         
         ; check u_data->u_ptab matches what we wanted
         ld hl, (U_DATA__U_PTAB) ; u_data->u_ptab
@@ -232,8 +231,7 @@ _dofork:
 
        ; Copy done
 
-       ld a, (U_DATA__U_PAGE)  ; parent memory
-       out (0), a              ; Switch context to parent
+       call map_process_always
 
        ; We are going to copy the uarea into the parents uarea stash
        ; we must not touch the parent uarea after this point, any
@@ -243,8 +241,8 @@ _dofork:
        ld bc, #U_DATA__TOTALSIZE
        ldir
        ; Return to the kernel mapping
-       ld a, #0x80
-       out (0), a
+       call map_kernel
+
         ; now the copy operation is complete we can get rid of the stuff
         ; _switchin will be expecting from our copy of the stack.
         pop bc
@@ -281,7 +279,7 @@ bankfork:
 bankfork_1:
        push bc                 ; Save our counter and also child offset
        push hl
-       out (0), a              ; switch to parent bank
+       call map_process_a
        ld de, #bouncebuffer
        ld bc, #256
        ldir                    ; copy into the bounce buffer
@@ -291,7 +289,7 @@ bankfork_1:
        push bc
        ld b, a                 ; save the parent bank id
        ld a, c                 ; switch to the child
-       out (0), a
+       call map_process_a
        push bc                 ; save the bank pointers
        ld hl, #bouncebuffer
        ld bc, #256