Hello,
On 06.04.2018 14:28, Daniel Kiper wrote:
> On Thu, Mar 29, 2018 at 11:20:37AM +0200, Alexander Boettcher wrote:
>
>> Can you please have a look and check regarding what should/could be
>> changed to get it upstream? We did not test the dynamic relocation part,
>
> Sure thing, please take a look below...
>
>> since we have no such (kernel) setup. Thanks in advance.
>
> You can use Xen (git://xenbits.xen.org/xen.git) for tests.
> Just compile hypervisor without any tools and use xen.gz.
> It produces nice output and you can see it is relocated or not.
> Of course you have to use Multiboot2 protocol.
Thanks, I managed to setup it. Based on your comments and on the Xen
test case I had to re-work the patch, so that it now works for
relocation and non-relocation kernels.
Please review again.
> However, this does not mean that I will not take this patch. Though
> it requires some tweaking.
>
> First of all, lack of SOB.
What is a SOB ?
Cheers,
--
Alexander Boettcher
Genode Labs
http://www.genode-labs.com - http://www.genode.org
Genode Labs GmbH - Amtsgericht Dresden - HRB 28424 - Sitz Dresden
Geschäftsführer: Dr.-Ing. Norman Feske, Christian Helmuth
From c37727840be8aeb81ea4bbc95ac09a1b1e3d3658 Mon Sep 17 00:00:00 2001
From: Alexander Boettcher <alexander.boettc...@genode-labs.com>
Date: Fri, 13 Apr 2018 23:37:01 +0200
Subject: [PATCH] mbi: use per segment a separate relocator chunk
if elf is non relocatable.
If the segments are not dense packed, the original code set up a huge
relocator chunk comprising all segments.
During the final relocation in grub_relocator_prepare_relocs, the chunk
is moved to its desired place and overrides memory which are actually not
covered/touched by the specified segments.
The overriden memory may contain device memory (vga text mode e.g.), which
leads to strange boot behaviour.
---
grub-core/loader/multiboot_elfxx.c | 56 ++++++++++++++++++++++++--------------
1 file changed, 35 insertions(+), 21 deletions(-)
diff --git a/grub-core/loader/multiboot_elfxx.c b/grub-core/loader/multiboot_elfxx.c
index 67daf59..d936223 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;
/* Calculate lowest and highest load address. */
for (i = 0; i < ehdr->e_phnum; i++)
@@ -108,27 +109,19 @@ 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
- 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;
- }
+ 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);
+ 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);
-
- 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);
+ 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);
+ }
/* Load every loadable segment in memory. */
for (i = 0; i < ehdr->e_phnum; i++)
@@ -139,7 +132,24 @@ 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;
+ 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;
+ }
+
+ if (mld->load_base_addr > get_physical_target_address (ch))
+ mld->load_base_addr = get_physical_target_address (ch);
+
+ source = get_virtual_current_address (ch);
+ }
if (phdr(i)->p_filesz != 0)
{
@@ -163,6 +173,10 @@ CONCAT(grub_multiboot_load_elf, XX) (mbi_load_data_t *mld)
}
}
+ 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);
+
for (i = 0; i < ehdr->e_phnum; i++)
if (phdr(i)->p_vaddr <= ehdr->e_entry
&& phdr(i)->p_vaddr + phdr(i)->p_memsz > ehdr->e_entry)
--
2.7.4
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