Re: [Qemu-devel] [PATCH] arm: fix arm kernel boot for non zero start addr

[Aurelien Jarno <aurelien@aurel32.net>]

On Sat, May 08, 2010 at 10:43:35PM +0200, Lars Munch wrote:
> Booting an arm kernel has been broken a while when booting from non zero start
> address. This is due to the order of events: board init loads the kernel and
> sets register 15 to the start address and then qemu_system_reset reset the cpu
> making register 15 zero again.
> 
> This patch fixes the usage of the register 15 start address trick in
> combination with arm_load_kernel.
> 
> Signed-off-by: Lars Munch <lars@segv.dk>
> ---
>  hw/arm_boot.c       |    1 +
>  hw/gumstix.c        |    4 ----
>  hw/mainstone.c      |    3 ---
>  hw/nseries.c        |    7 -------
>  hw/omap_sx1.c       |    5 -----
>  hw/palm.c           |    4 ----
>  hw/spitz.c          |    3 ---
>  hw/tosa.c           |    3 ---
>  target-arm/helper.c |    1 -
>  9 files changed, 1 insertions(+), 30 deletions(-)
> 
> diff --git a/hw/arm_boot.c b/hw/arm_boot.c
> index df031a5..620550b 100644
> --- a/hw/arm_boot.c
> +++ b/hw/arm_boot.c
> @@ -187,6 +187,7 @@ static void main_cpu_reset(void *opaque)
>              env->regs[15] = info->entry & 0xfffffffe;
>              env->thumb = info->entry & 1;
>          } else {
> +            env->regs[15] = info->loader_start;
>              if (old_param) {
>                  set_kernel_args_old(info, info->initrd_size,
>                                      info->loader_start);

This parts looks fine.

> diff --git a/hw/gumstix.c b/hw/gumstix.c
> index 3fd31f4..b64e04e 100644
> --- a/hw/gumstix.c
> +++ b/hw/gumstix.c
> @@ -74,8 +74,6 @@ static void connex_init(ram_addr_t ram_size,
>          exit(1);
>      }
>  
> -    cpu->env->regs[15] = 0x00000000;
> -
>      /* Interrupt line of NIC is connected to GPIO line 36 */
>      smc91c111_init(&nd_table[0], 0x04000300,
>                      pxa2xx_gpio_in_get(cpu->gpio)[36]);
> @@ -114,8 +112,6 @@ static void verdex_init(ram_addr_t ram_size,
>          exit(1);
>      }
>  
> -    cpu->env->regs[15] = 0x00000000;
> -
>      /* Interrupt line of NIC is connected to GPIO line 99 */
>      smc91c111_init(&nd_table[0], 0x04000300,
>                      pxa2xx_gpio_in_get(cpu->gpio)[99]);
> diff --git a/hw/mainstone.c b/hw/mainstone.c
> index a4379e3..54bacfb 100644
> --- a/hw/mainstone.c
> +++ b/hw/mainstone.c
> @@ -89,9 +89,6 @@ static void mainstone_common_init(ram_addr_t ram_size,
>      cpu_register_physical_memory(0, MAINSTONE_ROM,
>                      qemu_ram_alloc(MAINSTONE_ROM) | IO_MEM_ROM);
>  
> -    /* Setup initial (reset) machine state */
> -    cpu->env->regs[15] = mainstone_binfo.loader_start;
> -
>  #ifdef TARGET_WORDS_BIGENDIAN
>      be = 1;
>  #else
> diff --git a/hw/nseries.c b/hw/nseries.c
> index 0273eee..04a028d 100644
> --- a/hw/nseries.c
> +++ b/hw/nseries.c
> @@ -1016,7 +1016,6 @@ static void n8x0_boot_init(void *opaque)
>      n800_dss_init(&s->blizzard);
>  
>      /* CPU setup */
> -    s->cpu->env->regs[15] = s->cpu->env->boot_info->loader_start;
>      s->cpu->env->GE = 0x5;
>  
>      /* If the machine has a slided keyboard, open it */
> @@ -1317,11 +1316,6 @@ static void n8x0_init(ram_addr_t ram_size, const char *boot_device,
>      if (usb_enabled)
>          n8x0_usb_setup(s);
>  
> -    /* Setup initial (reset) machine state */
> -
> -    /* Start at the OneNAND bootloader.  */
> -    s->cpu->env->regs[15] = 0;
> -
>      if (kernel_filename) {
>          /* Or at the linux loader.  */
>          binfo->kernel_filename = kernel_filename;
> @@ -1330,7 +1324,6 @@ static void n8x0_init(ram_addr_t ram_size, const char *boot_device,
>          arm_load_kernel(s->cpu->env, binfo);
>  
>          qemu_register_reset(n8x0_boot_init, s);
> -        n8x0_boot_init(s);
>      }
>  
>      if (option_rom[0] && (boot_device[0] == 'n' || !kernel_filename)) {
> diff --git a/hw/omap_sx1.c b/hw/omap_sx1.c
> index ca0a7d1..2e9879f 100644
> --- a/hw/omap_sx1.c
> +++ b/hw/omap_sx1.c
> @@ -195,15 +195,10 @@ static void sx1_init(ram_addr_t ram_size,
>  
>      /* Load the kernel.  */
>      if (kernel_filename) {
> -        /* Start at bootloader.  */
> -        cpu->env->regs[15] = sx1_binfo.loader_start;
> -
>          sx1_binfo.kernel_filename = kernel_filename;
>          sx1_binfo.kernel_cmdline = kernel_cmdline;
>          sx1_binfo.initrd_filename = initrd_filename;
>          arm_load_kernel(cpu->env, &sx1_binfo);
> -    } else {
> -        cpu->env->regs[15] = 0x00000000;
>      }
>  
>      /* TODO: fix next line */
> diff --git a/hw/palm.c b/hw/palm.c
> index ba7c398..8db133d 100644
> --- a/hw/palm.c
> +++ b/hw/palm.c
> @@ -243,7 +243,6 @@ static void palmte_init(ram_addr_t ram_size,
>              rom_size = load_image_targphys(option_rom[0], OMAP_CS0_BASE,
>                                             flash_size);
>              rom_loaded = 1;
> -            cpu->env->regs[15] = 0x00000000;
>          }
>          if (rom_size < 0) {
>              fprintf(stderr, "%s: error loading '%s'\n",
> @@ -258,9 +257,6 @@ static void palmte_init(ram_addr_t ram_size,
>  
>      /* Load the kernel.  */
>      if (kernel_filename) {
> -        /* Start at bootloader.  */
> -        cpu->env->regs[15] = palmte_binfo.loader_start;
> -
>          palmte_binfo.kernel_filename = kernel_filename;
>          palmte_binfo.kernel_cmdline = kernel_cmdline;
>          palmte_binfo.initrd_filename = initrd_filename;
> diff --git a/hw/spitz.c b/hw/spitz.c
> index c3b5cd8..4f82e24 100644
> --- a/hw/spitz.c
> +++ b/hw/spitz.c
> @@ -993,9 +993,6 @@ static void spitz_common_init(ram_addr_t ram_size,
>          /* A 4.0 GB microdrive is permanently sitting in CF slot 0.  */
>          spitz_microdrive_attach(cpu, 0);
>  
> -    /* Setup initial (reset) machine state */
> -    cpu->env->regs[15] = spitz_binfo.loader_start;
> -
>      spitz_binfo.kernel_filename = kernel_filename;
>      spitz_binfo.kernel_cmdline = kernel_cmdline;
>      spitz_binfo.initrd_filename = initrd_filename;
> diff --git a/hw/tosa.c b/hw/tosa.c
> index bc6591f..fbe8d8c 100644
> --- a/hw/tosa.c
> +++ b/hw/tosa.c
> @@ -229,9 +229,6 @@ static void tosa_init(ram_addr_t ram_size,
>  
>      tosa_tg_init(cpu);
>  
> -    /* Setup initial (reset) machine state */
> -    cpu->env->regs[15] = tosa_binfo.loader_start;
> -
>      tosa_binfo.kernel_filename = kernel_filename;
>      tosa_binfo.kernel_cmdline = kernel_cmdline;
>      tosa_binfo.initrd_filename = initrd_filename;
> diff --git a/target-arm/helper.c b/target-arm/helper.c
> index 99e0394..63e5dc7 100644
> --- a/target-arm/helper.c
> +++ b/target-arm/helper.c
> @@ -207,7 +207,6 @@ 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.  Initial SP and PC are loaded from ROM.  */
>      if (IS_M(env)) {

This part doesn't. The register reset should be kept in case in case the
test "if (info)" in main_cpu_reset() is false.

-- 
Aurelien Jarno                          GPG: 1024D/F1BCDB73
aurelien@aurel32.net                 http://www.aurel32.net