CVS commit: src/sys/arch/amd64/amd64

[Maxime Villard]

Module Name:    src
Committed By:   maxv
Date:           Sat Aug 20 18:04:04 UTC 2016

Modified Files:
        src/sys/arch/amd64/amd64: gdt.c

Log Message:
The GDT needs to be grown on each CPU, and not just gdtstore (cpu0).
Otherwise, if the caller gets switched to another CPU, the kernel will
end up accessing unallocated memory.

Currently, it never happens. The same is done in i386.


To generate a diff of this commit:
cvs rdiff -u -r1.28 -r1.29 src/sys/arch/amd64/amd64/gdt.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.


Modified files:

Index: src/sys/arch/amd64/amd64/gdt.c
diff -u src/sys/arch/amd64/amd64/gdt.c:1.28 src/sys/arch/amd64/amd64/gdt.c:1.29
--- src/sys/arch/amd64/amd64/gdt.c:1.28	Sat Aug 20 17:34:23 2016
+++ src/sys/arch/amd64/amd64/gdt.c	Sat Aug 20 18:04:04 2016
@@ -1,4 +1,4 @@
-/*	$NetBSD: gdt.c,v 1.28 2016/08/20 17:34:23 christos Exp $	*/
+/*	$NetBSD: gdt.c,v 1.29 2016/08/20 18:04:04 maxv Exp $	*/
 
 /*-
  * Copyright (c) 1996, 1997, 2009 The NetBSD Foundation, Inc.
@@ -37,7 +37,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: gdt.c,v 1.28 2016/08/20 17:34:23 christos Exp $");
+__KERNEL_RCSID(0, "$NetBSD: gdt.c,v 1.29 2016/08/20 18:04:04 maxv Exp $");
 
 #include "opt_multiprocessor.h"
 #include "opt_xen.h"
@@ -206,12 +206,14 @@ gdt_reload_cpu(struct cpu_info *ci)
 #endif
 
 /*
- * Grow or shrink the GDT.
+ * Grow the GDT.
  */
 static void
 gdt_grow(void)
 {
 	size_t old_len, new_len;
+	CPU_INFO_ITERATOR cii;
+	struct cpu_info *ci;
 	struct vm_page *pg;
 	vaddr_t va;
 
@@ -221,15 +223,19 @@ gdt_grow(void)
 	gdt_dynavail =
 	    (gdt_size - DYNSEL_START) / sizeof(struct sys_segment_descriptor);
 
-	for (va = (vaddr_t)gdtstore + old_len; va < (vaddr_t)gdtstore + new_len;
-	    va += PAGE_SIZE) {
-		while ((pg = uvm_pagealloc(NULL, 0, NULL, UVM_PGA_ZERO)) ==
-		       NULL) {
-			uvm_wait("gdt_grow");
+	for (CPU_INFO_FOREACH(cii, ci)) {
+		for (va = (vaddr_t)(ci->ci_gdt) + old_len;
+		     va < (vaddr_t)(ci->ci_gdt) + new_len;
+		     va += PAGE_SIZE) {
+			while ((pg = uvm_pagealloc(NULL, 0, NULL, UVM_PGA_ZERO)) ==
+			    NULL) {
+				uvm_wait("gdt_grow");
+			}
+			pmap_kenter_pa(va, VM_PAGE_TO_PHYS(pg),
+			    VM_PROT_READ | VM_PROT_WRITE, 0);
 		}
-		pmap_kenter_pa(va, VM_PAGE_TO_PHYS(pg),
-		    VM_PROT_READ | VM_PROT_WRITE, 0);
 	}
+
 	pmap_update(pmap_kernel());
 }