Messages in this thread | | | Date | Sat, 20 Feb 2010 21:45:54 -0800 | From | "H. Peter Anvin" <> | Subject | Re: x86 embedded - Problem getting past 'move compressed kernel before decompression' |
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On 02/20/2010 06:03 PM, Graeme Russ wrote: > > The following is something I have hacked together to jump into the 32-bit > start address of the Linux Kernel: > > struct boot_params boot_params __attribute__((aligned(16))); > struct setup_header *hdr = (struct setup_header *)(0x90000 + 0x1f1); > > void boot_zimage(void *setup_base) > { > memset(&boot_params, 0x00, sizeof boot_params); > memcpy(&boot_params.hdr, hdr, sizeof (*hdr)); > > boot_params.alt_mem_k = 128 * 1024; > boot_params.e820_entries = 1; > boot_params.e820_map[0].addr = 0x00000000; > boot_params.e820_map[0].size = 128 * 1024; > boot_params.e820_map[0].type = 1; > > asm( "movw $0x18, %%cx\n" \ > "movl %%ecx, %%ds\n" \ > "movl %%ecx, %%es\n" \ > "movl %%ecx, %%fs\n" \ > "movl %%ecx, %%gs\n" \ > "movl %%ecx, %%ss\n" \ > "xorl %%ebp, %%ebp\n" \ > "xorl %%edi, %%edi\n" \ > "xorl %%ebx, %%ebx\n" \ > "movl %0, %%esi\n" ^^ > "movl $0x100000, %%eax\n" \ > "jmpl *%%eax" : : "r"(&boot_params)); ^
At this point you have probably clobbered the register that you have your boot_params in.
Instead, do something like:
asm volatile( "movl %0, %%ds\n" \ "movl %0, %%es\n" \ "movl %0, %%fs\n" \ "movl %0, %%gs\n" \ "movl %0, %%ss\n" \ "xorl %ebp, %ebp\n" \ "xorl %ebx, %ebx\n" \ "movl $0x100000, %%eax\n" \ "ljmpl $0x10,$0x100000" : : "S" (&boot_params), "D" (0), "c" (0x18));
-hpa
-- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.
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