ARMv7-M reset fixes

Move ARMv7-M PC/SP initialization to the CPU reset routine.  Add a board
reset routine to call this.  Also load values directly from ROM as
images have not been copied yet.

Avoid clearing the NVIC pointer on cpu reset.

Signed-off-by: Paul Brook <paul@codesourcery.com>

hw/armv7m.c

@@ -151,6 +151,12 @@ static void armv7m_bitband_init(void)
 }
 
 /* Board init.  */
+
+static void armv7m_reset(void *opaque)
+{
+    cpu_reset((CPUState *)opaque);
+}
+
 /* Init CPU and memory for a v7-M based board.
    flash_size and sram_size are in kb.
    Returns the NVIC array.  */
@@ -163,7 +169,6 @@ qemu_irq *armv7m_init(int flash_size, int sram_size,
     /* FIXME: make this local state.  */
     static qemu_irq pic[64];
     qemu_irq *cpu_pic;
-    uint32_t pc;
     int image_size;
     uint64_t entry;
     uint64_t lowaddr;
@@ -201,7 +206,7 @@ qemu_irq *armv7m_init(int flash_size, int sram_size,
     armv7m_bitband_init();
 
     nvic = qdev_create(NULL, "armv7m_nvic");
-    env->v7m.nvic = nvic;
+    env->nvic = nvic;
     qdev_init_nofail(nvic);
     cpu_pic = arm_pic_init_cpu(env);
     sysbus_connect_irq(sysbus_from_qdev(nvic), 0, cpu_pic[ARM_PIC_CPU_IRQ]);
@@ -227,24 +232,13 @@ qemu_irq *armv7m_init(int flash_size, int sram_size,
         exit(1);
     }
 
-    /* If the image was loaded at address zero then assume it is a
-       regular ROM image and perform the normal CPU reset sequence.
-       Otherwise jump directly to the entry point.  */
-    if (lowaddr == 0) {
-	env->regs[13] = ldl_phys(0);
-	pc = ldl_phys(4);
-    } else {
-	pc = entry;
-    }
-    env->thumb = pc & 1;
-    env->regs[15] = pc & ~1;
-
     /* Hack to map an additional page of ram at the top of the address
        space.  This stops qemu complaining about executing code outside RAM
        when returning from an exception.  */
     cpu_register_physical_memory(0xfffff000, 0x1000,
                                  qemu_ram_alloc(0x1000) | IO_MEM_RAM);
 
+    qemu_register_reset(armv7m_reset, env);
     return pic;
 }
 

target-arm/cpu.h

@@ -146,7 +146,6 @@ typedef struct CPUARMState {
         int current_sp;
         int exception;
         int pending_exception;
-        void *nvic;
     } v7m;
 
     /* Coprocessor IO used by peripherals */
@@ -205,6 +204,7 @@ typedef struct CPUARMState {
     CPU_COMMON
 
     /* These fields after the common ones so they are preserved on reset.  */
+    void *nvic;
     struct arm_boot_info *boot_info;
 } CPUARMState;
 

target-arm/helper.c

@@ -8,6 +8,7 @@
 #include "helpers.h"
 #include "qemu-common.h"
 #include "host-utils.h"
+#include "hw/loader.h"
 
 static uint32_t cortexa9_cp15_c0_c1[8] =
 { 0x1031, 0x11, 0x000, 0, 0x00100103, 0x20000000, 0x01230000, 0x00002111 };
@@ -204,14 +205,28 @@ void cpu_reset(CPUARMState *env)
 #else
     /* SVC mode with interrupts disabled.  */
     env->uncached_cpsr = ARM_CPU_MODE_SVC | CPSR_A | CPSR_F | CPSR_I;
+    env->regs[15] = 0;
     /* On ARMv7-M the CPSR_I is the value of the PRIMASK register, and is
-       clear at reset.  */
+       clear at reset.  Initial SP and PC are loaded from ROM.  */
-    if (IS_M(env))
+    if (IS_M(env)) {
+        uint32_t pc;
+        uint8_t *rom;
         env->uncached_cpsr &= ~CPSR_I;
+        rom = rom_ptr(0);
+        if (rom) {
+            /* We should really use ldl_phys here, in case the guest
+               modified flash and reset itself.  However images
+               loaded via -kenrel have not been copied yet, so load the
+               values directly from there.  */
+            env->regs[13] = ldl_p(rom);
+            pc = ldl_p(rom + 4);
+            env->thumb = pc & 1;
+            env->regs[15] = pc & ~1;
+        }
+    }
     env->vfp.xregs[ARM_VFP_FPEXC] = 0;
     env->cp15.c2_base_mask = 0xffffc000u;
 #endif
-    env->regs[15] = 0;
     tlb_flush(env, 1);
 }
 
@@ -624,7 +639,7 @@ static void do_v7m_exception_exit(CPUARMState *env)
 
     type = env->regs[15];
     if (env->v7m.exception != 0)
-        armv7m_nvic_complete_irq(env->v7m.nvic, env->v7m.exception);
+        armv7m_nvic_complete_irq(env->nvic, env->v7m.exception);
 
     /* Switch to the target stack.  */
     switch_v7m_sp(env, (type & 4) != 0);
@@ -666,15 +681,15 @@ static void do_interrupt_v7m(CPUARMState *env)
        one we're raising.  */
     switch (env->exception_index) {
     case EXCP_UDEF:
-        armv7m_nvic_set_pending(env->v7m.nvic, ARMV7M_EXCP_USAGE);
+        armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_USAGE);
         return;
     case EXCP_SWI:
         env->regs[15] += 2;
-        armv7m_nvic_set_pending(env->v7m.nvic, ARMV7M_EXCP_SVC);
+        armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_SVC);
         return;
     case EXCP_PREFETCH_ABORT:
     case EXCP_DATA_ABORT:
-        armv7m_nvic_set_pending(env->v7m.nvic, ARMV7M_EXCP_MEM);
+        armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_MEM);
         return;
     case EXCP_BKPT:
         if (semihosting_enabled) {
@@ -686,10 +701,10 @@ static void do_interrupt_v7m(CPUARMState *env)
                 return;
             }
         }
-        armv7m_nvic_set_pending(env->v7m.nvic, ARMV7M_EXCP_DEBUG);
+        armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_DEBUG);
         return;
     case EXCP_IRQ:
-        env->v7m.exception = armv7m_nvic_acknowledge_irq(env->v7m.nvic);
+        env->v7m.exception = armv7m_nvic_acknowledge_irq(env->nvic);
         break;
     case EXCP_EXCEPTION_EXIT:
         do_v7m_exception_exit(env);