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Dont add UPAGES to the %cs segment limit. There is nothing there except

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page tables.
This commit is contained in:
peter 2001-08-23 01:25:21 +00:00
parent 640090e351
commit c0a555fd02
2 changed files with 4 additions and 32 deletions
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18
sys/amd64/amd64/machdep.c
View File

@ -1875,25 +1875,11 @@ init386(first)
/* make ldt memory segments */
/*
* The data segment limit must not cover the user area because we
* don't want the user area to be writable in copyout() etc. (page
* level protection is lost in kernel mode on 386's). Also, we
* don't want the user area to be writable directly (page level
* protection of the user area is not available on 486's with
* CR0_WP set, because there is no user-read/kernel-write mode).
*
* XXX - VM_MAXUSER_ADDRESS is an end address, not a max. And it
* should be spelled ...MAX_USER...
*/
#define VM_END_USER_RW_ADDRESS VM_MAXUSER_ADDRESS
/*
* The code segment limit has to cover the user area until we move
* the signal trampoline out of the user area. This is safe because
* the code segment cannot be written to directly.
*/
#define VM_END_USER_R_ADDRESS (VM_END_USER_RW_ADDRESS + UPAGES * PAGE_SIZE)
ldt_segs[LUCODE_SEL].ssd_limit = atop(VM_END_USER_R_ADDRESS - 1);
ldt_segs[LUDATA_SEL].ssd_limit = atop(VM_END_USER_RW_ADDRESS - 1);
ldt_segs[LUCODE_SEL].ssd_limit = atop(VM_MAXUSER_ADDRESS - 1);
ldt_segs[LUDATA_SEL].ssd_limit = atop(VM_MAXUSER_ADDRESS - 1);
for (x = 0; x < sizeof ldt_segs / sizeof ldt_segs[0]; x++)
ssdtosd(&ldt_segs[x], &ldt[x].sd);

18
sys/i386/i386/machdep.c
View File

@ -1875,25 +1875,11 @@ init386(first)
/* make ldt memory segments */
/*
* The data segment limit must not cover the user area because we
* don't want the user area to be writable in copyout() etc. (page
* level protection is lost in kernel mode on 386's). Also, we
* don't want the user area to be writable directly (page level
* protection of the user area is not available on 486's with
* CR0_WP set, because there is no user-read/kernel-write mode).
*
* XXX - VM_MAXUSER_ADDRESS is an end address, not a max. And it
* should be spelled ...MAX_USER...
*/
#define VM_END_USER_RW_ADDRESS VM_MAXUSER_ADDRESS
/*
* The code segment limit has to cover the user area until we move
* the signal trampoline out of the user area. This is safe because
* the code segment cannot be written to directly.
*/
#define VM_END_USER_R_ADDRESS (VM_END_USER_RW_ADDRESS + UPAGES * PAGE_SIZE)
ldt_segs[LUCODE_SEL].ssd_limit = atop(VM_END_USER_R_ADDRESS - 1);
ldt_segs[LUDATA_SEL].ssd_limit = atop(VM_END_USER_RW_ADDRESS - 1);
ldt_segs[LUCODE_SEL].ssd_limit = atop(VM_MAXUSER_ADDRESS - 1);
ldt_segs[LUDATA_SEL].ssd_limit = atop(VM_MAXUSER_ADDRESS - 1);
for (x = 0; x < sizeof ldt_segs / sizeof ldt_segs[0]; x++)
ssdtosd(&ldt_segs[x], &ldt[x].sd);