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Re: [PATCH v2] mbi: use per segment a separate relocator chunk
From: |
Alexander Boettcher |
Subject: |
Re: [PATCH v2] mbi: use per segment a separate relocator chunk |
Date: |
Tue, 12 Jun 2018 20:18:19 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 |
Agree, resend it as v3 patch.
On 11.06.2018 22:09, Daniel Kiper wrote:
> 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 <address@hidden>
>> ---
>> 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
>
> _______________________________________________
> Grub-devel mailing list
> address@hidden
> https://lists.gnu.org/mailman/listinfo/grub-devel
>
--
Alexander Boettcher
Genode Labs
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