On Fri, 24 Dec 2010, Mark Kettenis wrote:
> Well, changing NLDT to 17 should defenitely be tested, but leaving it
> at 17 is a bit odd. I'm actually wondering whether the default LDT is
> necessary at all now that LBSDICALLS_SEL is gone. Then NLDT can go
> completely.
>From a brief look, eliminating the default entirely just makes things more
complicated, but we can shrink it down to 1. I switched things over to
using malloc instead of uvm_km_alloc because there's no reason to allocate
full pages for tiny things.
This will need more testing, of course.
Index: i386/machdep.c
===================================================================
RCS file: /cvs/src/sys/arch/i386/i386/machdep.c,v
retrieving revision 1.485
diff -u -r1.485 machdep.c
--- i386/machdep.c 2 Oct 2010 23:31:34 -0000 1.485
+++ i386/machdep.c 24 Dec 2010 21:35:04 -0000
@@ -2868,7 +2868,7 @@
union descriptor *cpu_ldt;
size_t len = sizeof(ldt);
- cpu_ldt = (union descriptor *)uvm_km_alloc(kernel_map, len);
+ cpu_ldt = malloc(len, M_DEVBUF, M_WAITOK);
bcopy(ldt, cpu_ldt, len);
ci->ci_ldt = cpu_ldt;
ci->ci_ldt_len = len;
Index: i386/pmap.c
===================================================================
RCS file: /cvs/src/sys/arch/i386/i386/pmap.c,v
retrieving revision 1.151
diff -u -r1.151 pmap.c
--- i386/pmap.c 30 Nov 2010 19:28:59 -0000 1.151
+++ i386/pmap.c 24 Dec 2010 21:35:06 -0000
@@ -1547,8 +1547,7 @@
* we're the last one to use it.
*/
ldt_free(pmap);
- uvm_km_free(kernel_map, (vaddr_t)pmap->pm_ldt,
- pmap->pm_ldt_len * sizeof(union descriptor));
+ free(pmap->pm_ldt, M_DEVBUF);
}
#endif
pool_put(&pmap_pmap_pool, pmap);
@@ -1586,11 +1585,7 @@
size_t len;
len = pmap1->pm_ldt_len * sizeof(union descriptor);
- new_ldt = (union descriptor *)uvm_km_alloc(kernel_map, len);
- if (new_ldt == NULL) {
- /* XXX needs to be able to fail properly */
- panic("pmap_fork: out of kva");
- }
+ new_ldt = malloc(len, M_DEVBUF, M_WAITOK);
bcopy(pmap1->pm_ldt, new_ldt, len);
pmap2->pm_ldt = new_ldt;
pmap2->pm_ldt_len = pmap1->pm_ldt_len;
@@ -1642,7 +1637,7 @@
simple_unlock(&pmap->pm_obj.vmobjlock);
if (old_ldt != NULL)
- uvm_km_free(kernel_map, (vaddr_t)old_ldt, len);
+ free(old_ldt, M_DEVBUF);
}
#endif /* USER_LDT */
Index: i386/sys_machdep.c
===================================================================
RCS file: /cvs/src/sys/arch/i386/i386/sys_machdep.c,v
retrieving revision 1.27
diff -u -r1.27 sys_machdep.c
--- i386/sys_machdep.c 20 Nov 2010 20:21:13 -0000 1.27
+++ i386/sys_machdep.c 24 Dec 2010 21:35:06 -0000
@@ -262,8 +262,7 @@
new_len = ldt_len * sizeof(union descriptor);
simple_unlock(&pmap->pm_lock);
- new_ldt = (union descriptor *)uvm_km_alloc(kernel_map,
- new_len);
+ new_ldt = malloc(new_len, M_DEVBUF, M_WAITOK);
if (new_ldt == NULL) {
error = ENOMEM;
goto out;
@@ -279,7 +278,7 @@
* hey.. not our problem if user applications
* have race conditions like that.
*/
- uvm_km_free(kernel_map, (vaddr_t)new_ldt, new_len);
+ free(new_ldt, M_DEVBUF);
goto copy;
}
@@ -296,7 +295,7 @@
memset((caddr_t)new_ldt + old_len, 0, new_len - old_len);
if (old_ldt != ldt)
- uvm_km_free(kernel_map, (vaddr_t)old_ldt, old_len);
+ free(old_ldt, M_DEVBUF);
pmap->pm_ldt = new_ldt;
pmap->pm_ldt_len = ldt_len;
Index: include/segments.h
===================================================================
RCS file: /cvs/src/sys/arch/i386/include/segments.h,v
retrieving revision 1.18
diff -u -r1.18 segments.h
--- include/segments.h 24 Dec 2010 20:26:30 -0000 1.18
+++ include/segments.h 24 Dec 2010 21:35:06 -0000
@@ -227,7 +227,8 @@
/*
* Entries in the Local Descriptor Table (LDT)
+ * (not normally used)
*/
-#define NLDT 17
+#define NLDT 1
#endif /* _I386_SEGMENTS_H_ */
