On Thu, 10 May 2018, Kirill A. Shutemov wrote:
> + /*
> + * paging_prepare() and cleanup_trampoline() below can have GOT
> + * references. Adjust the table with address we are running at.
> + */
> +
> + /* The GOP was not adjusted before */
GOP == EFI speak for Graphics Output Protocol. What the heck?
> + xorq %rax, %rax
And this clearing of RAX is related to this because? Sure you need it for
adjust_got() but adding a comment to that is too much asked for, right?
> + /* Calculate the address the binary is loaded at. */
> + call 1f
> +1: popq %rdi
> + subq $1b, %rdi
> +
> + call adjust_gop
> +
> /*
> * At this point we are in long mode with 4-level paging enabled,
> * but we might want to enable 5-level paging or vice versa.
> @@ -381,6 +396,24 @@ trampoline_return:
> pushq $0
> popfq
>
> + /*
> + * Previously we've adjusted the GOT with address the binary was
> + * loaded at. Now we need to re-adjust for relocation address.
> + */
Breaking up those comments makes it more readable, right?
> + /*
> + * Calculate the address the binary is loaded at.
> + * This address was used to adjust the table before and we need to
> + * undo the change.
> + */
> + call 1f
> +1: popq %rax
> + subq $1b, %rax
> +
> + /* The new adjustment is relocation address */
is the relocation address
> + movq %rbx, %rdi
> + call adjust_gop
> +
> /*
> * Copy the compressed kernel to the end of our buffer
> * where decompression in place becomes safe.
> @@ -481,19 +514,6 @@ relocated:
> shrq $3, %rcx
> rep stosq
>
> -/*
> - * Adjust our own GOT
> - */
> - leaq _got(%rip), %rdx
> - leaq _egot(%rip), %rcx
> -1:
> - cmpq %rcx, %rdx
> - jae 2f
> - addq %rbx, (%rdx)
> - addq $8, %rdx
> - jmp 1b
> -2:
> -
> /*
> * Do the extraction, and jump to the new kernel..
> */
> @@ -512,6 +532,26 @@ relocated:
> */
> jmp *%rax
>
> +/*
> + * Adjust global offest table
offest?
> + *
> + * RAX is previous adjustment of the table to undo (0 if it's the first time
> we touch GOP).
is the previous
And there is no reason to make that line overly long.
> + * RDI is the new adjustment to apply.
> + */
> +adjust_gop:
> + /* Walk through the GOT adding the address to the entries */
> + leaq _got(%rip), %rdx
> + leaq _egot(%rip), %rcx
> +1:
> + cmpq %rcx, %rdx
> + jae 2f
> + subq %rax, (%rdx) /* Undo previous adjustment */
> + addq %rdi, (%rdx) /* Apply the new adjustment */
> + addq $8, %rdx
> + jmp 1b
> +2:
> + ret
I'm really tired of your carelessness. The amount of half baken stuff you
submit is way above the tolerance level by now. I asked you several times
to be more careful, but you simply do not care at all. Get your act
together finally.
Thanks,
tglx
