| Message ID | 1373441632-17323-1-git-send-email-grant.likely@linaro.org |
|---|---|
| State | New |
| Headers | show |
On 10 July 2013 08:33, Grant Likely <grant.likely@linaro.org> wrote: > Sometimes we want to boot the system via firmware instead of loading a > kernel into ram with the -kernel parameter. This patch makes the -kernel > parameter optional so that a bios image provided by the -pflash flag > will be executed. > > For example: > qemu-system-arm -M vexpress-a15 -pflash <filename> > > Note: Currently the file must be at least the size of the emulated flash > device (64M) otherwise QEMU will silently not use the data. This will be > fixed in a separate patch > > This is part of the larger solution. For this to work it requires the > platform to have flash mapped or aliased to address 0 so that there is > some code for the emulator to execute. That patch is already on list :-) > Signed-off-by: Grant Likely <grant.likely@linaro.org> > Cc: Peter Maydell <peter.maydell@linaro.org> > Cc: qemu-devel@nongnu.org > --- > > hw/arm/boot.c | 47 ++++++++++++++++++++++------------------------- > 1 file changed, 22 insertions(+), 25 deletions(-) > > diff --git a/hw/arm/boot.c b/hw/arm/boot.c > index 7c0090f..3b9e108 100644 > --- a/hw/arm/boot.c > +++ b/hw/arm/boot.c > @@ -361,12 +361,6 @@ void arm_load_kernel(ARMCPU *cpu, struct arm_boot_info *info) > int big_endian; > QemuOpts *machine_opts; > > - /* Load the kernel. */ > - if (!info->kernel_filename) { > - fprintf(stderr, "Kernel image must be specified\n"); > - exit(1); > - } Why can't we just return from the function here? If we don't have a kernel we can assume we don't have a dtb or an initrd either. I don't think we want to do any of the other weird stuff with setting up a reset handler or boot pen for the secondary CPUs either -- we should just assume the bootrom image in the flash handles this. thanks -- PMM
On Wed, Jul 10, 2013 at 8:44 AM, Peter Maydell <peter.maydell@linaro.org> wrote: > On 10 July 2013 08:33, Grant Likely <grant.likely@linaro.org> wrote: >> Sometimes we want to boot the system via firmware instead of loading a >> kernel into ram with the -kernel parameter. This patch makes the -kernel >> parameter optional so that a bios image provided by the -pflash flag >> will be executed. >> >> For example: >> qemu-system-arm -M vexpress-a15 -pflash <filename> >> >> Note: Currently the file must be at least the size of the emulated flash >> device (64M) otherwise QEMU will silently not use the data. This will be >> fixed in a separate patch >> >> This is part of the larger solution. For this to work it requires the >> platform to have flash mapped or aliased to address 0 so that there is >> some code for the emulator to execute. > > That patch is already on list :-) Heh, I wrote the above before grabbing and testing your patch. >> diff --git a/hw/arm/boot.c b/hw/arm/boot.c >> index 7c0090f..3b9e108 100644 >> --- a/hw/arm/boot.c >> +++ b/hw/arm/boot.c >> @@ -361,12 +361,6 @@ void arm_load_kernel(ARMCPU *cpu, struct arm_boot_info *info) >> int big_endian; >> QemuOpts *machine_opts; >> >> - /* Load the kernel. */ >> - if (!info->kernel_filename) { >> - fprintf(stderr, "Kernel image must be specified\n"); >> - exit(1); >> - } > > Why can't we just return from the function here? If we don't > have a kernel we can assume we don't have a dtb or an initrd > either. I don't think we want to do any of the other weird > stuff with setting up a reset handler or boot pen for the > secondary CPUs either -- we should just assume the bootrom > image in the flash handles this. I've just tested this, and you're right. I assumed that some of the other stuff would be necessary, but it does work just fine to return. Second version of the patch posted now. g.
diff --git a/hw/arm/boot.c b/hw/arm/boot.c index 7c0090f..3b9e108 100644 --- a/hw/arm/boot.c +++ b/hw/arm/boot.c @@ -361,12 +361,6 @@ void arm_load_kernel(ARMCPU *cpu, struct arm_boot_info *info) int big_endian; QemuOpts *machine_opts; - /* Load the kernel. */ - if (!info->kernel_filename) { - fprintf(stderr, "Kernel image must be specified\n"); - exit(1); - } - machine_opts = qemu_opts_find(qemu_find_opts("machine"), 0); if (machine_opts) { info->dtb_filename = qemu_opt_get(machine_opts, "dtb"); @@ -403,26 +397,29 @@ void arm_load_kernel(ARMCPU *cpu, struct arm_boot_info *info) info->initrd_start = info->loader_start + MIN(info->ram_size / 2, 128 * 1024 * 1024); - /* Assume that raw images are linux kernels, and ELF images are not. */ - kernel_size = load_elf(info->kernel_filename, NULL, NULL, &elf_entry, - NULL, NULL, big_endian, ELF_MACHINE, 1); - entry = elf_entry; - if (kernel_size < 0) { - kernel_size = load_uimage(info->kernel_filename, &entry, NULL, - &is_linux); - } - if (kernel_size < 0) { - entry = info->loader_start + KERNEL_LOAD_ADDR; - kernel_size = load_image_targphys(info->kernel_filename, entry, - info->ram_size - KERNEL_LOAD_ADDR); - is_linux = 1; - } - if (kernel_size < 0) { - fprintf(stderr, "qemu: could not load kernel '%s'\n", - info->kernel_filename); - exit(1); + if (info->kernel_filename) { + /* Assume that raw images are linux kernels, and ELF images are not. */ + kernel_size = load_elf(info->kernel_filename, NULL, NULL, &elf_entry, + NULL, NULL, big_endian, ELF_MACHINE, 1); + entry = elf_entry; + if (kernel_size < 0) { + kernel_size = load_uimage(info->kernel_filename, &entry, NULL, + &is_linux); + } + if (kernel_size < 0) { + entry = info->loader_start + KERNEL_LOAD_ADDR; + kernel_size = load_image_targphys(info->kernel_filename, entry, + info->ram_size - KERNEL_LOAD_ADDR); + is_linux = 1; + } + if (kernel_size < 0) { + fprintf(stderr, "qemu: could not load kernel '%s'\n", + info->kernel_filename); + exit(1); + } + info->entry = entry; } - info->entry = entry; + if (is_linux) { if (info->initrd_filename) { initrd_size = load_image_targphys(info->initrd_filename,
Sometimes we want to boot the system via firmware instead of loading a kernel into ram with the -kernel parameter. This patch makes the -kernel parameter optional so that a bios image provided by the -pflash flag will be executed. For example: qemu-system-arm -M vexpress-a15 -pflash <filename> Note: Currently the file must be at least the size of the emulated flash device (64M) otherwise QEMU will silently not use the data. This will be fixed in a separate patch This is part of the larger solution. For this to work it requires the platform to have flash mapped or aliased to address 0 so that there is some code for the emulator to execute. Signed-off-by: Grant Likely <grant.likely@linaro.org> Cc: Peter Maydell <peter.maydell@linaro.org> Cc: qemu-devel@nongnu.org --- hw/arm/boot.c | 47 ++++++++++++++++++++++------------------------- 1 file changed, 22 insertions(+), 25 deletions(-)