Author: ian
Date: Tue Dec 26 19:02:56 2017
New Revision: 327222
URL: https://svnweb.freebsd.org/changeset/base/327222
Log:
Add a new ARM kernel option, LOCORE_MAP_MB, to control the size of the
kernel VA mapping in the temporary page tables set up by locore-v6.S.
The number used to be hard-coded to 64MB, which is still the default if
the kernel option is not specified. However, 64MB is insufficient for
using a large mdroot filesystem. The hard-coded number can't be safely
increased because too large a number may run into memory-mapped IO space
on some SoCs that must not be mapped as ordinary memory.
Modified:
head/sys/arm/arm/genassym.c
head/sys/arm/arm/locore-v6.S
head/sys/conf/options.arm
Modified: head/sys/arm/arm/genassym.c
==============================================================================
--- head/sys/arm/arm/genassym.c Tue Dec 26 18:42:29 2017 (r327221)
+++ head/sys/arm/arm/genassym.c Tue Dec 26 19:02:56 2017 (r327222)
@@ -161,3 +161,12 @@ ASSYM(DCACHE_LINE_SIZE, offsetof(struct cpuinfo, dcach
ASSYM(DCACHE_LINE_MASK, offsetof(struct cpuinfo, dcache_line_mask));
ASSYM(ICACHE_LINE_SIZE, offsetof(struct cpuinfo, icache_line_size));
ASSYM(ICACHE_LINE_MASK, offsetof(struct cpuinfo, icache_line_mask));
+
+/*
+ * Emit the LOCORE_MAP_MB option as a #define only if the option was set.
+ */
+#include "opt_locore.h"
+
+#ifdef LOCORE_MAP_MB
+ASSYM(LOCORE_MAP_MB, LOCORE_MAP_MB);
+#endif
Modified: head/sys/arm/arm/locore-v6.S
==============================================================================
--- head/sys/arm/arm/locore-v6.S Tue Dec 26 18:42:29 2017
(r327221)
+++ head/sys/arm/arm/locore-v6.S Tue Dec 26 19:02:56 2017
(r327222)
@@ -38,6 +38,11 @@
__FBSDID("$FreeBSD$");
+/* We map 64MB of kernel unless overridden in assym.s by the kernel option. */
+#ifndef LOCORE_MAP_MB
+#define LOCORE_MAP_MB 64
+#endif
+
#if __ARM_ARCH >= 7
#if defined(__ARM_ARCH_7VE__) || defined(__clang__)
/*
@@ -176,12 +181,13 @@ ASENTRY_NP(_start)
bl build_pagetables
/*
- * Next we do 64MiB starting at the physical load address, mapped to
- * the VA the kernel is linked for.
+ * Next we map the kernel starting at the physical load address, mapped
+ * to the VA the kernel is linked for. The default size we map is 64MiB
+ * but it can be overridden with a kernel option.
*/
mov r1, r5
ldr r2, =(KERNVIRTADDR)
- mov r3, #64
+ ldr r3, =(LOCORE_MAP_MB)
bl build_pagetables
/* Create a device mapping for early_printf if specified. */
Modified: head/sys/conf/options.arm
==============================================================================
--- head/sys/conf/options.arm Tue Dec 26 18:42:29 2017 (r327221)
+++ head/sys/conf/options.arm Tue Dec 26 19:02:56 2017 (r327222)
@@ -35,6 +35,7 @@ KERNBASE opt_global.h
KERNVIRTADDR opt_global.h
LINUX_BOOT_ABI opt_global.h
LOADERRAMADDR opt_global.h
+LOCORE_MAP_MB opt_locore.h
NKPT2PG opt_pmap.h
PHYSADDR opt_global.h
PLATFORM opt_global.h
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