[Qemu-devel] [Bug 696094] Re: TI Stellaris lm3s811evb (ARM Cortex-M3) : Systick interrupt not working

[Frikkie Thirion]

** Attachment added: "Project demonstrating that SysTick interrupt doesn't 
execute correctly."
   
https://bugs.launchpad.net/bugs/696094/+attachment/1780598/+files/project.tar.bz2

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https://bugs.launchpad.net/bugs/696094

Title:
  TI Stellaris lm3s811evb (ARM Cortex-M3) : Systick interrupt not working

Status in QEMU:
  New

Bug description:
  I've tried to create a small project that uses the CMSIS as base library.
The problem is that the SysTick_interrupt_handler() doesn't get executed when 
the systick event is detected in QEMU. Furthermore, it seems asif QEMU gets 
stuck in an endless loop. QEMU doesn't respond to Ctrl-C on the command line 
and the GDB session also stalls. 'kill -9' is the only way to stop QEMU.

It seems asif the initialisation of the NVIC works fine. I've traced the 
function calls in QEMU as follows:
stellaris.c: stellaris_init() - Perform generic armv7 init: armv7m_init()
   armv7m.c: armv7m_init() - Create and init the nvic:
                               nvic = qdev_create(NULL, "armv7m_nvic");
                               env->nvic = nvic;
                               qdev_init_nofail(nvic);
                           - Configure the programmable interrupt controller:
                               Call: arm_pic_init_cpu() 
                                        qemu_allocate_irqs(arm_pic_cpu_handler)
                           - Initialise 64 interrupt structures.

The following call sequence is observed when the systick event occur:
armv7m_nvic.c: systick_timer_tick(): set pending interrupt
armv7m_nvic.c: armv7m_nvic_set_pending() for irq:15
  arm_gic.c: gic_set_pending_private(): GIC_SET_PENDING(15,)
    arm_gic.c: gic_update() - Raise IRQ with qemu_set_irq()
       irq.c: eqmu_set_irq() - Call the irq->handler 
                               -- I assume the irq handler is 
'arm_pic_cpu_handler()',
                                  since that was passed as the parameter when
                                  qemu_allocate_irqs() was called in ...
          arm_pic.c: arm_pic_cpu_handler() - After evaluation, call 
cpu_interrupt()
             exec.c: cpu_interrupt() is called.     

The tools that were used during the testing of this project:
  GCC: Codesourcery ARM eabi 2010q3
  QEMU: Checked out on 31/12/2010 - Last commit: 
0fcec41eec0432c77645b4a407d3a3e030c4abc4
The project files are attached, for reproducing of the errors.
   Note: The CMSIS wants to perform byte accesses to the NVIC. For the 
Cortex-M3, unaligned 8 bit and 16 bit accesses are allowed. The current QEMU 
implementation doesn't yet cater for it. As a work around, updated versions of
arm_gic.c armv7m_nvic.h armv7m_nvic.c is also included.

Launch project with: go_gdb.sh
Attach debugger with: arm-none-eabi-gdbtui --command=gdbCommands_tui
(s = step, n = next, c = continue, Ctrl-C = stop, print <variable> to look at 
variable contents)