Just black screen after running Qemu

Question

I have just installed QEMU and compiled linux kernel with ARM support but when I run below command

qemu-system-arm -M versatilepb -m 128M -kernel /home/arit/         


        

Answer 1

As you asking Is this config file is responsible for setting up entry and load address of uImage

Yes make ARCH=arm CROSS_COMPILE=arm-none-linux-gnueabi- uImage

this command is responsible for loading entry point. How ? --->In kernel source code open vi scripts/mkuboot.sh

here check MKIMAGE=$(type -path "${CROSS_COMPILE}mkimage")

the script will take care to call scripts/Makefile.lib.

here in code

MKIMAGE := $(srctree)/scripts/mkuboot.sh

  UIMAGE_ARCH ?= $(SRCARCH)
  UIMAGE_COMPRESSION ?= $(if $(2),$(2),none)
  UIMAGE_OPTS-y ?=
  UIMAGE_TYPE ?= kernel
  UIMAGE_LOADADDR ?= arch_must_set_this
  UIMAGE_ENTRYADDR ?= $(UIMAGE_LOADADDR)
  UIMAGE_NAME ?= 'Linux-$(KERNELRELEASE)'
  UIMAGE_IN ?= $<
  UIMAGE_OUT ?= $@

-->

if the user doesnt mention LOADADDR in command line the address is took from below
UIMAGE_LOADADDR ?= arch_must_set_this

ifneq ($(LOADADDR),)
UIMAGE_LOADADDR=$(LOADADDR)
else
   ifeq ($(CONFIG_ZBOOT_ROM),y)
   UIMAGE_LOADADDR=$(CONFIG_ZBOOT_ROM_TEXT)
  else
UIMAGE_LOADADDR=$(ZRELADDR)
endif
endif

UIMAGE_LOADADDR=$(ZRELADDR) --> this variable responsible for loading entry address

the valve $(ZRELADDR) is took from board specific for in our case versatile so

arch/arm/mach-versatile/Makefile.boot

here

   zreladdr-y   += 0x00008000
params_phys-y   := 0x00000100
initrd_phys-y   := 0x00800000

This is how in kernel scripts are automated when make ARCH=arm CROSS_COMPILE=arm-none-linux-gnueabi- uImage

executed.