On Tue, Jun 05, 2018 at 10:14:49PM +0200, Alexander Boettcher wrote:
> Instead of setting up a all comprising relocator chunk for all segments,
> use per segment a separate relocator chunk.
>
> If the ELF is non-relocatable, a single relocator chunk will comprise memory
> (between the segments) which gets overridden by the relst() invocation of the
> movers code in grub_relocator16/32/64_boot().
>
> The overridden memory may contain reserved ranges like VGA memory or ACPI
> tables, which leads to strange boot behaviour.
>
> Signed-off-by: Alexander Boettcher <alexander.boettc...@genode-labs.com>
> ---
> grub-core/loader/multiboot_elfxx.c | 60
> +++++++++++++++++++++++---------------
> 1 file changed, 37 insertions(+), 23 deletions(-)
>
> diff --git a/grub-core/loader/multiboot_elfxx.c
> b/grub-core/loader/multiboot_elfxx.c
> index 67daf59..6565b50 100644
> --- a/grub-core/loader/multiboot_elfxx.c
> +++ b/grub-core/loader/multiboot_elfxx.c
> @@ -57,9 +57,9 @@ CONCAT(grub_multiboot_load_elf, XX) (mbi_load_data_t *mld)
> char *phdr_base;
> grub_err_t err;
> grub_relocator_chunk_t ch;
> - grub_uint32_t load_offset, load_size;
> + grub_uint32_t load_offset = 0, load_size;
> int i;
> - void *source;
> + void *source = NULL;
>
> if (ehdr->e_ident[EI_MAG0] != ELFMAG0
> || ehdr->e_ident[EI_MAG1] != ELFMAG1
> @@ -83,6 +83,7 @@ CONCAT(grub_multiboot_load_elf, XX) (mbi_load_data_t *mld)
> #define phdr(i) ((Elf_Phdr *) (phdr_base + (i) *
> ehdr->e_phentsize))
>
> mld->link_base_addr = ~0;
> + mld->load_base_addr = ~0;
We do not need it. Please look below.
> /* Calculate lowest and highest load address. */
> for (i = 0; i < ehdr->e_phnum; i++)
> @@ -97,10 +98,15 @@ CONCAT(grub_multiboot_load_elf, XX) (mbi_load_data_t *mld)
> return grub_error (GRUB_ERR_BAD_OS, "segment crosses 4 GiB border");
> #endif
>
> - load_size = highest_load - mld->link_base_addr;
> + grub_dprintf ("multiboot_loader", "link_base_addr=0x%x, relocatable=%d, "
> + "align=0x%lx, preference=0x%x, avoid_efi_boot_services=%d\n",
> + mld->link_base_addr, mld->relocatable, (long) mld->align,
> + mld->preference, mld->avoid_efi_boot_services);
I have just realized that it does not make sense to print align,
preference and avoid_efi_boot_services if mld->relocatable is not
set. Please take a look at grub-core/loader/multiboot_mbi2.c for
more details. Sorry about that. In this case you can probably drop
this grub_dprintf() and...
> if (mld->relocatable)
> {
> + load_size = highest_load - mld->link_base_addr;
> +
> if (load_size > mld->max_addr || mld->min_addr > mld->max_addr -
> load_size)
> return grub_error (GRUB_ERR_BAD_OS, "invalid min/max address and/or
> load size");
>
> @@ -108,27 +114,16 @@ CONCAT(grub_multiboot_load_elf, XX) (mbi_load_data_t
> *mld)
> mld->min_addr, mld->max_addr -
> load_size,
> load_size, mld->align ?
> mld->align : 1,
> mld->preference,
> mld->avoid_efi_boot_services);
> - }
> - else
Please do not drop this else. You can put this here:
mld->load_base_addr = mld->link_base_addr;
load_base_addr == link_base_addr in non relocatable case.
Am I right?
> - err = grub_relocator_alloc_chunk_addr (GRUB_MULTIBOOT (relocator), &ch,
> - mld->link_base_addr, load_size);
> -
> - if (err)
> - {
> - grub_dprintf ("multiboot_loader", "Cannot allocate memory for OS
> image\n");
> - return err;
> - }
>
> - mld->load_base_addr = get_physical_target_address (ch);
> - source = get_virtual_current_address (ch);
> -
> - grub_dprintf ("multiboot_loader", "link_base_addr=0x%x,
> load_base_addr=0x%x, "
> - "load_size=0x%x, relocatable=%d\n", mld->link_base_addr,
> - mld->load_base_addr, load_size, mld->relocatable);
...you can leave this excluding load_size and...
> + if (err)
> + {
> + grub_dprintf ("multiboot_loader", "Cannot allocate memory for OS
> image\n");
> + return err;
> + }
>
> - if (mld->relocatable)
> - grub_dprintf ("multiboot_loader", "align=0x%lx, preference=0x%x,
> avoid_efi_boot_services=%d\n",
> - (long) mld->align, mld->preference,
> mld->avoid_efi_boot_services);
...you can leave this grub_dprintf() and move load_size from above.
You can put it after preference.
> + mld->load_base_addr = get_physical_target_address (ch);
> + source = get_virtual_current_address (ch);
> + }
>
> /* Load every loadable segment in memory. */
> for (i = 0; i < ehdr->e_phnum; i++)
> @@ -139,7 +134,26 @@ CONCAT(grub_multiboot_load_elf, XX) (mbi_load_data_t
> *mld)
> grub_dprintf ("multiboot_loader", "segment %d: paddr=0x%lx,
> memsz=0x%lx, vaddr=0x%lx\n",
> i, (long) phdr(i)->p_paddr, (long) phdr(i)->p_memsz,
> (long) phdr(i)->p_vaddr);
>
> - load_offset = phdr(i)->p_paddr - mld->link_base_addr;
> + if (mld->relocatable)
> + load_offset = phdr(i)->p_paddr - mld->link_base_addr;
Please add this here:
grub_dprintf ("multiboot_loader", "segment %d: load_offset=0x%x\n", i,
load_offset);
> + else
> + {
> + err = grub_relocator_alloc_chunk_addr (GRUB_MULTIBOOT
> (relocator), &ch,
> + phdr(i)->p_paddr,
> phdr(i)->p_memsz);
> +
> + if (err)
> + {
> + grub_dprintf ("multiboot_loader", "Cannot allocate memory for
> OS image\n");
> + return err;
> + }
> +
> + mld->load_base_addr = grub_min (mld->load_base_addr,
> get_physical_target_address (ch));
You can drop this. Please look above.
> +
> + source = get_virtual_current_address (ch);
> + }
> +
> + grub_dprintf ("multiboot_loader", "segment %d: load_base_addr=0x%x, "
> + "load_offset=0x%x\n", i, mld->load_base_addr,
> load_offset);
Please drop this grub_dprintf().
Daniel
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