[ARM] nommu: fixups for the exception vectors

The high page vector (0xFFFF0000) does not supported in nommu mode.
This patch allows the vectors to be 0x00000000 or the begining of DRAM
in nommu mode.

Signed-off-by: Hyok S. Choi <hyok.choi@samsung.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 32ba00bd0a2f4398cde7bad3c602bdfda42ca48a..b674614d090bd5b660697b2e43ef4cf6d3520e30 100644 (file)
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -72,6 +72,14 @@ config FIQ
 config ARCH_MTD_XIP
        bool
 
+config VECTORS_BASE
+       hex
+       default 0xffff0000 if MMU
+       default DRAM_BASE if REMAP_VECTORS_TO_RAM
+       default 0x00000000
+       help
+         The base address of exception vectors.
+
 source "init/Kconfig"
 
 menu "System Type"

diff --git a/arch/arm/Kconfig-nommu b/arch/arm/Kconfig-nommu
index 8ce56e5bd78fe14b90c86a55522e37482fcfd288..e1574be2ded614e05633c715381df9086d69f776 100644 (file)
--- a/arch/arm/Kconfig-nommu
+++ b/arch/arm/Kconfig-nommu
@@ -25,3 +25,20 @@ config FLASH_SIZE
        hex 'FLASH Size' if SET_MEM_PARAM
        default 0x00400000
 
+config REMAP_VECTORS_TO_RAM
+       bool 'Install vectors to the begining of RAM' if DRAM_BASE
+       depends on DRAM_BASE
+       help
+         The kernel needs to change the hardware exception vectors.
+         In nommu mode, the hardware exception vectors are normally
+         placed at address 0x00000000. However, this region may be
+         occupied by read-only memory depending on H/W design.
+
+         If the region contains read-write memory, say 'n' here.
+
+         If your CPU provides a remap facility which allows the exception
+         vectors to be mapped to writable memory, say 'n' here.
+
+         Otherwise, say 'y' here.  In this case, the kernel will require
+         external support to redirect the hardware exception vectors to
+         the writable versions located at DRAM_BASE.

diff --git a/arch/arm/kernel/signal.h b/arch/arm/kernel/signal.h
index 9991049c522d65ef50873d8d923f8d5021f9fce8..27beece1550263e3555e140f06b115aae034fb2b 100644 (file)
--- a/arch/arm/kernel/signal.h
+++ b/arch/arm/kernel/signal.h
@@ -7,6 +7,6 @@
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  */
-#define KERN_SIGRETURN_CODE    0xffff0500
+#define KERN_SIGRETURN_CODE    (CONFIG_VECTORS_BASE + 0x00000500)
 
 extern const unsigned long sigreturn_codes[7];

diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index 03924bcc61293169c70bd65f48325a6a849c2514..32b0570329e71204992390f3d0b56a446647f13a 100644 (file)
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -688,6 +688,7 @@ EXPORT_SYMBOL(abort);
 
 void __init trap_init(void)
 {
+       unsigned long vectors = CONFIG_VECTORS_BASE;
        extern char __stubs_start[], __stubs_end[];
        extern char __vectors_start[], __vectors_end[];
        extern char __kuser_helper_start[], __kuser_helper_end[];
@@ -698,9 +699,9 @@ void __init trap_init(void)
         * into the vector page, mapped at 0xffff0000, and ensure these
         * are visible to the instruction stream.
         */
-       memcpy((void *)0xffff0000, __vectors_start, __vectors_end - __vectors_start);
-       memcpy((void *)0xffff0200, __stubs_start, __stubs_end - __stubs_start);
-       memcpy((void *)0xffff1000 - kuser_sz, __kuser_helper_start, kuser_sz);
+       memcpy((void *)vectors, __vectors_start, __vectors_end - __vectors_start);
+       memcpy((void *)vectors + 0x200, __stubs_start, __stubs_end - __stubs_start);
+       memcpy((void *)vectors + 0x1000 - kuser_sz, __kuser_helper_start, kuser_sz);
 
        /*
         * Copy signal return handlers into the vector page, and
@@ -709,6 +710,6 @@ void __init trap_init(void)
        memcpy((void *)KERN_SIGRETURN_CODE, sigreturn_codes,
               sizeof(sigreturn_codes));
 
-       flush_icache_range(0xffff0000, 0xffff0000 + PAGE_SIZE);
+       flush_icache_range(vectors, vectors + PAGE_SIZE);
        modify_domain(DOMAIN_USER, DOMAIN_CLIENT);
 }