Re: Relocation overflow on RISC-V with multi-range memory layout

[Vladimir 'phcoder' Serbinenko]

That is not the correct solution. Correct solution is to use trampoline facility like e.g. ppc does. Can you post the full reproduction instructions?

Le lun. 25 sept. 2023, 10:53, Wu, Fei <fei2.wu@intel.com> a écrit :

Hi All,

I'm enabling PCIe passthrough on qemu riscv, the physical memory
range between 3GB and 4GB is reserved. Therefore if guest has 4GB ram,
two ranges are created as [2G, 3G) and [4G, 7G). More details can be
found here:
https://lore.kernel.org/all/CAKmqyKMtAzt5saCUMd4vXYfgAQibpzQJAhtTSuSb+yeKhcYpfw@mail.gmail.com/T/

When run grub.efi from uefi shell, a relocation problem happened in
grub_arch_dl_relocate_symbols() of grub-core/kern/riscv/dl.c:

        case R_RISCV_CALL:
        case R_RISCV_CALL_PLT:
          {
            grub_uint32_t *abs_place = place;
            grub_ssize_t off = sym_addr - (grub_addr_t) place;
            grub_uint32_t hi20, lo12;

            if (off != (grub_int32_t) off)
              return grub_error (GRUB_ERR_BAD_MODULE, "relocation
overflow");

It requires `off' in the range of int32, but it's not enforced since the
>4GB memory can be used. I'm not familiar with grub, but this patch does
work for me:

--- a/include/grub/riscv64/efi/memory.h
+++ b/include/grub/riscv64/efi/memory.h
@@ -1,6 +1,6 @@
 #ifndef GRUB_MEMORY_CPU_HEADER
 #include <grub/efi/memory.h>

-#define GRUB_EFI_MAX_USABLE_ADDRESS 0xffffffffffffULL
+#define GRUB_EFI_MAX_USABLE_ADDRESS 0xffffffffULL

Any comments?

Thanks,
Fei.

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