change startup code to call munmap()/munmap_text() to map out

own 0-pages.

diff --git a/lib/i386/rts/crtso.s b/lib/i386/rts/crtso.s
index a43c74a3c9078688b3f8ac4a2639ddfbf712008c..c78cab14a605e86e9ac766c742a99b3f6cc0a20f 100755 (executable)
--- a/lib/i386/rts/crtso.s
+++ b/lib/i386/rts/crtso.s
@@ -1,3 +1,4 @@
+#
 ! This is the C run-time start-off routine.  It's job is to take the
 ! arguments as put on the stack by EXEC, and to parse them and set them up the
 ! way _main expects them.
@@ -6,6 +7,8 @@
 ! simplistic.  We simply check for some magic value, but there is no other
 ! way.
 
+#include <sys/vm_i386.h>
+
 .sect .text; .sect .rom; .sect .data; .sect .bss
 
 .define begtext, begdata, begbss
@@ -19,6 +22,7 @@ begdata:
 begbss:
 
 .define crtso, __penviron, __penvp, __fpu_present
+.define __minix_datastart, __minix_mainjump, __minix_unmapzero
 .extern _main, _exit
 .sect .text
 crtso:
@@ -49,6 +53,12 @@ crtso:
        smsw    ax
        testb   al, 0x4                 ! EM bit in MSW
        setz    (__fpu_present)         ! True if not set
+       jmp __minix_mainjump
+
+.align I386_PAGE_SIZE
+__minix_mainjump:
+       ! unmap zero pages
+       call    __minix_unmapzero
 
        call    _main                   ! main(argc, argv, envp)
 
@@ -57,10 +67,27 @@ crtso:
 
        hlt                             ! force a trap if exit fails
 
+__minix_unmapzero:
+
+       ! unmap 0-page code
+       push    I386_PAGE_SIZE
+       push    crtso
+       call    _munmap_text            ! munmap_text(crtso, I386_PAGE_SIZE)
+       add     esp, 8
+
+       ! unmap 0-page data
+       push    I386_PAGE_SIZE
+       push    romstart
+       call    _munmap                 ! munmap(romstart, I386_PAGE_SIZE)
+       add     esp, 8
+
+       ret
+
 .sect .rom
-       .data4  0                       ! Separate I&D: *NULL == 0
-                                       ! Also keeps the first string in the
-                                       ! program from appearing at location 0!
+romstart:
+       .space  I386_PAGE_SIZE
+__minix_datastart:
+       .space  4
 .sect .data
 __penviron:
        .data4  __penvp                 ! Pointer to environ, or hidden pointer