Messages in this thread | | | Date | Wed, 21 Nov 2012 11:45:47 -0800 | Subject | Re: [PATCH v3 01/12] x86, boot: move verify_cpu.S after 0x200 | From | Yinghai Lu <> |
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On Wed, Nov 21, 2012 at 9:23 AM, H. Peter Anvin <hpa@zytor.com> wrote: > On 11/20/2012 11:15 PM, Yinghai Lu wrote: >> >> We are short of space before 0x200 that is entry for startup_64. >> >> And we can not change startup_64 to other value --- ABI ? > > > Here you are saying "I don't understand how this works." It is YOUR > responsibility to find out and write a definite statement rather than > leaving that to the reader, or expect the maintainer to edit this.
actually, i can not find that out. in the code of arch/x86/boot/compressed/head_64.S
/* * Be careful here startup_64 needs to be at a predictable * address so I can export it in an ELF header. Bootloaders * should look at the ELF header to find this address, as * it may change in the future. */ .code64 .org 0x200 ENTRY(startup_64) /* * We come here either from startup_32 or directly from a * 64bit bootloader. If we come here from a bootloader we depend on * an identity mapped page table being provied that maps our * entire text+data+bss and hopefully all of memory. */ #ifdef CONFIG_EFI_STUB /* * The entry point for the PE/COFF executable is 0x210, so only * legacy boot loaders will execute this jmp. */ jmp preferred_addr
.org 0x210 mov %rcx, %rdi
and it says that 0x200 will be changed later..
so you said it has to stay with 0x200, do you mean 0x210 from PE/COFF force that?
wonder if you are considering attatched patch to move startup_64 down... we could kill one jmp.
Thanks
Yinghai [unhandled content-type:application/octet-stream] | |