evans@ditsyda.oz (Bruce.Evans) (07/02/90)
Although my 386 Minix kernel has not been posted yet, this bug fix seems
important enough to post. Pages were being remapped from low memory to
extended memory beginning at 2M even when 2M was not the end of extended
memory. This causes the corresponding number of pages at the top of the
final memory memory map to be bad. With more than 1M of extended memory,
the top pages are rarely allocated so the bug would not bite often. The
bug only affects the most recent (June 1990) version of the kernel.
There are bugs in test8 that seem to be more dangerous with this kernel.
Test8 calls mknod with the wrong number of arguments. This creates
directories and files with "random" sizes, including possibly negative
sizes. Big sizes cause directory seaches to take "forever", and negative
sizes may cause panics. Test8 should not be run until these calls and
mknod are fixed.
#! /bin/sh
# This is a shell archive. Remove anything before this line, then unpack
# it by saving it into a file and typing "sh file". To overwrite existing
# files, type "sh file -c". You can also feed this as standard input via
# unshar, or by typing "sh <file", e.g.. If this archive is complete, you
# will see the following message at the end:
# "End of shell archive."
# Contents: klib386.x.crc klib386.x.cdif
# Wrapped by evans@ditsyda on Mon Jul 2 22:36:27 1990
PATH=/bin:/usr/bin:/usr/ucb ; export PATH
if test -f 'klib386.x.crc' -a "${1}" != "-c" ; then
echo shar: Will not clobber existing file \"'klib386.x.crc'\"
else
echo shar: Extracting \"'klib386.x.crc'\" \(47 characters\)
sed "s/^X//" >'klib386.x.crc' <<'END_OF_FILE'
X54263 20437 klib386.x
X43247 19739 klib386.x~
END_OF_FILE
if test 47 -ne `wc -c <'klib386.x.crc'`; then
echo shar: \"'klib386.x.crc'\" unpacked with wrong size!
fi
# end of 'klib386.x.crc'
fi
if test -f 'klib386.x.cdif' -a "${1}" != "-c" ; then
echo shar: Will not clobber existing file \"'klib386.x.cdif'\"
else
echo shar: Extracting \"'klib386.x.cdif'\" \(3717 characters\)
sed "s/^X//" >'klib386.x.cdif' <<'END_OF_FILE'
X*** dist/klib386.x Thu Apr 26 20:23:07 1990
X--- klib386.x Mon Jul 2 22:23:53 1990
X***************
X*** 44,55 ****
X /* Paging constants. */
X! #define CR0_PG 0x80000000
X! #define LOG2_MEM_UNIT 10
X! #define LOG2_PAGE_SIZE 12
X! #define MEM_UNIT 1024
X! #define NR_PAGE_DIRS 1
X! #define NR_PAGE_TABLES 4
X! #define PAGE_DATA_SIZE 4
X! #define PAGE_SIZE 0x1000
X! #define PAGE_DIR_SIZE 0x1000
X! #define PAGE_TABLE_SIZE 0x1000
X
X--- 44,57 ----
X /* Paging constants. */
X! #define CR0_PG 0x80000000
X! #define EXTENDED_MEM_BASE 0x100000
X! #define LOG2_MEM_UNIT 10
X! #define LOG2_PAGE_DATA_SIZE 2
X! #define LOG2_PAGE_SIZE 12
X! #define MEM_UNIT 1024
X! #define NR_PAGE_DIRS 1
X! #define NR_PAGE_TABLES 4
X! #define PAGE_DATA_SIZE 4
X! #define PAGE_SIZE 0x1000
X! #define PAGE_DIR_SIZE 0x1000
X! #define PAGE_TABLE_SIZE 0x1000
X
X***************
X*** 328,330 ****
X mov cr3,edi | use for page directory base
X!
X push es
X--- 328,330 ----
X mov cr3,edi | use for page directory base
X!
X push es
X***************
X*** 332,334 ****
X mov es,ax
X!
X mov eax,_low_memsize
X--- 332,334 ----
X mov es,ax
X!
X mov eax,_low_memsize
X***************
X*** 335,337 ****
X mov ecx,edi
X! shr ecx,#LOG2_MEM_UNIT | assume MEM_UNIT <= PAGE_SIZE
X mov _low_memsize,ecx | now it ends at the page directory
X--- 335,340 ----
X mov ecx,edi
X! #if MEM_UNIT > PAGE_SIZE
X! #error /* several calculations depend on MEM_UNIT <= PAGE_SIZE */
X! #endif
X! shr ecx,#LOG2_MEM_UNIT
X mov _low_memsize,ecx | now it ends at the page directory
X***************
X*** 342,345 ****
X shl eax,#LOG2_PAGE_SIZE-LOG2_MEM_UNIT
X! add _ext_memsize,eax
X!
X lea eax,PAGE_DIR_SIZE+0x07(edi) | 0x07 is some access bits
X--- 345,353 ----
X shl eax,#LOG2_PAGE_SIZE-LOG2_MEM_UNIT
X! mov ecx,_ext_memsize
X! and ecx,#!(PAGE_SIZE/MEM_UNIT-1) | round down so top of extended
X! | memory is at a page boundary
X! push ecx
X! add ecx,eax
X! mov _ext_memsize,ecx
X!
X lea eax,PAGE_DIR_SIZE+0x07(edi) | 0x07 is some access bits
X***************
X*** 350,352 ****
X loop init_page_dir
X!
X sub eax,eax
X--- 358,360 ----
X loop init_page_dir
X!
X sub eax,eax
X***************
X*** 355,357 ****
X stosd
X!
X mov eax,#0x07
X--- 363,365 ----
X stosd
X!
X mov eax,#0x07
X***************
X*** 365,369 ****
X or eax,#0x07
X! add edi,#-NR_PAGE_TABLES*PAGE_TABLE_SIZE+0x200000/PAGE_SIZE*PAGE_DATA_SIZE
X! | 2M is end of extended mem
X pop ecx | number of pages stolen from low mem
X init_stolen_page_table:
X--- 373,386 ----
X or eax,#0x07
X! add edi,#-NR_PAGE_TABLES*PAGE_TABLE_SIZE+EXTENDED_MEM_BASE/PAGE_SIZE*PAGE_DATA_SIZE
X! | page table for beginning of ext mem
X! pop ecx | size of extended memory
X! #if LOG2_MEM_UNIT-LOG2_PAGE_SIZE+LOG2_PAGE_DATA_SIZE > 0
X! shl ecx,#LOG2_MEM_UNIT-LOG2_PAGE_SIZE+LOG2_PAGE_DATA_SIZE
X! #endif
X! #if LOG2_MEM_UNIT-LOG2_PAGE_SIZE+LOG2_PAGE_DATA_SIZE < 0
X! shr ecx,#LOG2_PAGE_SIZE-LOG2_PAGE_DATA_SIZE-LOG2_MEM_UNIT
X! #endif
X! add edi,ecx | page table for orig end of ext mem
X pop ecx | number of pages stolen from low mem
X+ jcxz over_init_stolen_page_table
X init_stolen_page_table:
X***************
X*** 372,374 ****
X loop init_stolen_page_table
X!
X #if UNPORTABLE_PAGING
X--- 389,392 ----
X loop init_stolen_page_table
X! over_init_stolen_page_table:
X!
X #if UNPORTABLE_PAGING
X***************
X*** 382,384 ****
X add _ext_memsize,#0x60000/MEM_UNIT
X!
X mov eax,#0xB0007 | Hercules memory at 0xB0000
X--- 400,402 ----
X add _ext_memsize,#0x60000/MEM_UNIT
X!
X mov eax,#0xB0007 | Hercules memory at 0xB0000
X***************
X*** 390,392 ****
X add _ext_memsize,#0x8000/MEM_UNIT
X!
X #endif /* UNPORTABLE_PAGING */
X--- 408,410 ----
X add _ext_memsize,#0x8000/MEM_UNIT
X!
X #endif /* UNPORTABLE_PAGING */
END_OF_FILE
if test 3717 -ne `wc -c <'klib386.x.cdif'`; then
echo shar: \"'klib386.x.cdif'\" unpacked with wrong size!
fi
# end of 'klib386.x.cdif'
fi
echo shar: End of shell archive.
exit 0
--
Bruce Evans evans@ditsyda.syd.dit.csiro.au