[Qemu-devel] [PATCH target-arm] arm: armv7m: Respect elf entry point

[Peter Crosthwaite <crosthwaitepeter@gmail.com>]

ARMv7M has it's own bootloader (separate from the regular ARM
bootloader) that is elf aware. It is able to load elfs but it does
not set the program counter to the elf entry point. Make it more
consistent with the regular ARM bootloader by setting the program
counter to the given elf entry point.

Signed-off-by: Peter Crosthwaite <crosthwaite.peter@gmail.com>
---
 hw/arm/armv7m.c | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/hw/arm/armv7m.c b/hw/arm/armv7m.c
index 397e8df..d1b983f 100644
--- a/hw/arm/armv7m.c
+++ b/hw/arm/armv7m.c
@@ -155,11 +155,18 @@ static void armv7m_bitband_init(void)
 
 /* Board init.  */
 
+typedef struct ARMV7MResetArgs {
+    ARMCPU *cpu;
+    uint32_t reset_pc;
+} ARMV7MResetArgs;
+
 static void armv7m_reset(void *opaque)
 {
-    ARMCPU *cpu = opaque;
+    ARMV7MResetArgs *args = opaque;
 
-    cpu_reset(CPU(cpu));
+    cpu_reset(CPU(args->cpu));
+    args->cpu->env.regs[15] = args->reset_pc;
+    args->cpu->env.thumb = args->reset_pc & 1;
 }
 
 /* Init CPU and memory for a v7-M based board.
@@ -183,6 +190,7 @@ qemu_irq *armv7m_init(MemoryRegion *address_space_mem,
     MemoryRegion *sram = g_new(MemoryRegion, 1);
     MemoryRegion *flash = g_new(MemoryRegion, 1);
     MemoryRegion *hack = g_new(MemoryRegion, 1);
+    ARMV7MResetArgs reset_args;
 
     flash_size *= 1024;
     sram_size *= 1024;
@@ -259,7 +267,12 @@ qemu_irq *armv7m_init(MemoryRegion *address_space_mem,
     vmstate_register_ram_global(hack);
     memory_region_add_subregion(address_space_mem, 0xfffff000, hack);
 
-    qemu_register_reset(armv7m_reset, cpu);
+    reset_args = (ARMV7MResetArgs) {
+        .cpu = cpu,
+        .reset_pc = entry,
+    };
+    qemu_register_reset(armv7m_reset,
+                        g_memdup(&reset_args, sizeof(reset_args)));
     return pic;
 }
 
-- 
1.9.1