On Wed, 2007-04-04 at 13:03 -0300, Glauber de Oliveira Costa wrote:
> This is a new version of the unified lguest launcher that applies to
> the current tree. According to rusty's suggestion, I'm bothering less
> to be able to load 32 bit kernels on 64-bit machines: changing the
> launcher for such case would be the easy part! In the absence of
> further objections, I'll commit it.
>
> Signed-off-by: Glauber de Oliveira Costa <gcosta@xxxxxxxxxx>
Hi Glauber!
The patch looks more than reasonable, but I think we can go further with
the abstraction. If you could spin it again, I'll apply it. There may
be more cleanups after that, but I don't want to hold up your progress!
> --- /dev/null
> +++ linux-2.6.20/Documentation/lguest/i386/defines
> @@ -0,0 +1,4 @@
> +# We rely on CONFIG_PAGE_OFFSET to know where to put lguest binary.
> +# Some shells (dash - ubunu) can't handle numbers that big so we cheat.
> +include ../../.config
> +LGUEST_GUEST_TOP := ($(CONFIG_PAGE_OFFSET) - 0x08000000)
The include needs another ../ and seems redundant (the .config is
included from the Makefile anyway).
The shells comment is obsolete and should be deleted too, my bad.
> +++ linux-2.6.20/Documentation/lguest/i386/lguest_defs.h
> @@ -0,0 +1,9 @@
> +#ifndef _LGUEST_DEFS_H_
> +#define _LGUEST_DEFS_H_
> +
> +/* LGUEST_TOP_ADDRESS comes from the Makefile */
> +#define RESERVE_TOP_ADDRESS LGUEST_GUEST_TOP - 1024*1024
Why -1M? And RESERVE_TOP_ADDRESS isn't used in this patch?
> +static unsigned long map_elf(int elf_fd, const void *hdr,
> unsigned long *page_offset)
> {
> - void *addr;
> +#ifndef __x86_64__
> + const Elf32_Ehdr *ehdr = hdr;
> Elf32_Phdr phdr[ehdr->e_phnum];
> +#else
> + const Elf64_Ehdr *ehdr = hdr;
> + Elf64_Phdr phdr[ehdr->e_phnum];
> +#endif
The way we did this in the module code was to define Elf_Ehdr etc in the
arch-specific headers to avoid ifdefs. I think it would help this code,
too.
> + || ((ehdr->e_machine != EM_386) &&
> + (ehdr->e_machine != EM_X86_64))
Similarly define ELF_MACHINE?
> else if (*page_offset != phdr[i].p_vaddr - phdr[i].p_paddr)
> + else if ((*page_offset != phdr[i].p_vaddr - phdr[i].p_paddr)
> +#ifdef __x86_64__
> + && (phdr[i].p_vaddr != VSYSCALL_START)
> +#endif
> + )
Hmm, static inline bool is_vsyscall_segment(const Elf_Phdr *) maybe?
> +/* LGUEST_TOP_ADDRESS comes from the Makefile */
> +typedef uint64_t u64;
> +#include "../../../include/asm/lguest_user.h"
> +
> +#define RESERVE_TOP_ADDRESS LGUEST_GUEST_TOP
> +
> +
> +#define BOOT_PGTABLE "boot_level4_pgt"
The comment should refer to LGUEST_GUEST_TOP?
I think the typedef should be in the main code with the others: it
doesn't hurt i386 and it's neater.
I'm not sure the BOOT_PGTABLE define helps us here, either; it might be
clearer just to put it directly into the code.
Cheers!
Rusty.
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