Thumb-2: Implementation of the unified start-up and exceptions code

This patch implements the ARM/Thumb-2 unified kernel start-up and
exception handling code.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

1 files changed, 21 insertions, 7 deletions

diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index bc5e4128f9f3..d4d4f77c91b2 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -25,6 +25,7 @@
 #include <linux/smp.h>
 #include <linux/fs.h>
 
+#include <asm/unified.h>
 #include <asm/cpu.h>
 #include <asm/cputype.h>
 #include <asm/elf.h>
@@ -327,25 +328,38 @@ void cpu_init(void)
         }
 
         /*
+         * Define the placement constraint for the inline asm directive below.
+         * In Thumb-2, msr with an immediate value is not allowed.
+         */
+#ifdef CONFIG_THUMB2_KERNEL
+#define PLC     "r"
+#else
+#define PLC     "I"
+#endif
+
+        /*
          * setup stacks for re-entrant exception handlers
          */
         __asm__ (
         "msr    cpsr_c, %1\n\t"
-        "add    sp, %0, %2\n\t"
+        "add    r14, %0, %2\n\t"
+        "mov    sp, r14\n\t"
         "msr    cpsr_c, %3\n\t"
-        "add    sp, %0, %4\n\t"
+        "add    r14, %0, %4\n\t"
+        "mov    sp, r14\n\t"
         "msr    cpsr_c, %5\n\t"
-        "add    sp, %0, %6\n\t"
+        "add    r14, %0, %6\n\t"
+        "mov    sp, r14\n\t"
         "msr    cpsr_c, %7"
             :
             : "r" (stk),
-              "I" (PSR_F_BIT | PSR_I_BIT | IRQ_MODE),
+              PLC (PSR_F_BIT | PSR_I_BIT | IRQ_MODE),
               "I" (offsetof(struct stack, irq[0])),
-              "I" (PSR_F_BIT | PSR_I_BIT | ABT_MODE),
+              PLC (PSR_F_BIT | PSR_I_BIT | ABT_MODE),
               "I" (offsetof(struct stack, abt[0])),
-              "I" (PSR_F_BIT | PSR_I_BIT | UND_MODE),
+              PLC (PSR_F_BIT | PSR_I_BIT | UND_MODE),
               "I" (offsetof(struct stack, und[0])),
-              "I" (PSR_F_BIT | PSR_I_BIT | SVC_MODE)
+              PLC (PSR_F_BIT | PSR_I_BIT | SVC_MODE)
             : "r14");
 }