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authorkib <kib@FreeBSD.org>2015-04-27 08:02:12 +0000
committerkib <kib@FreeBSD.org>2015-04-27 08:02:12 +0000
commitfacaa68fb95e65d46783aee588e7c99ae11d5e76 (patch)
tree2490a68d0f0407f65b7522b1e69ee07cc835dfe8 /sys/conf/options.i386
parentbc0b39657e72b1c736b37854e76ac5d962c82641 (diff)
downloadFreeBSD-src-facaa68fb95e65d46783aee588e7c99ae11d5e76.zip
FreeBSD-src-facaa68fb95e65d46783aee588e7c99ae11d5e76.tar.gz
MFC r281495:
Add config option PAE_TABLES for the i386 kernel. It switches pmap to use PAE format for the page tables, but does not incur other consequences of the full PAE config. In particular, vm_paddr_t and bus_addr_t are left 32bit, and max supported memory is still limited by 4GB. The option allows to have nx permissions for memory mappings on i386 kernel, while keeping the usual i386 KBI and avoiding the kernel data sizing problems typical for the PAE config.
Diffstat (limited to 'sys/conf/options.i386')
-rw-r--r--sys/conf/options.i3865
1 files changed, 5 insertions, 0 deletions
diff --git a/sys/conf/options.i386 b/sys/conf/options.i386
index 7e64a80..7102d8f 100644
--- a/sys/conf/options.i386
+++ b/sys/conf/options.i386
@@ -37,6 +37,11 @@ KVA_PAGES opt_global.h
# Physical address extensions and support for >4G ram. As above.
PAE opt_global.h
+# Use PAE page tables, but limit memory support to 4GB.
+# This keeps the i386 non-PAE KBI, in particular, drivers see
+# 32bit vm_paddr_t.
+PAE_TABLES opt_global.h
+
TIMER_FREQ opt_clock.h
CPU_ATHLON_SSE_HACK opt_cpu.h
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