Re: [PATCH v8 1/3] riscv: Introduce CONFIG_RELOCATABLE

From: Palmer Dabbelt
Date: Fri May 12 2023 - 14:41:27 EST


On Thu, 11 May 2023 11:18:23 PDT (-0700), schwab@xxxxxxxxxxxxxx wrote:
On Mai 09 2023, Alexandre Ghiti wrote:

On 5/9/23 21:07, Andreas Schwab wrote:
That does not work with UEFI booting:

Loading Linux 6.4.0-rc1-1.g668187d-default ...
Loading initial ramdisk ...
Unhandled exception: Instruction access fault
EPC: ffffffff80016d56 RA: 000000008020334e TVAL: 0000007f80016d56
EPC: ffffffff002d1d56 RA: 00000000004be34e reloc adjusted
Unhandled exception: Load access fault
EPC: 00000000fff462d4 RA: 00000000fff462d0 TVAL: ffffffff80016d56
EPC: 00000000802012d4 RA: 00000000802012d0 reloc adjusted

Code: c825 8e0d 05b3 40b4 d0ef 0636 7493 ffe4 (d783 0004)
UEFI image [0x00000000fe65e000:0x00000000fe6e3fff] '/efi\boot\bootriscv64.efi'
UEFI image [0x00000000daa82000:0x00000000dcc2afff]


I need more details please, as I have a UEFI bootflow and it works great
(KASLR is based on a relocatable kernel and works fine in UEFI too).

It also crashes without UEFI. Disabling CONFIG_RELOCATABLE fixes that.
This was tested on the HiFive Unmatched board.
The kernel image I tested is available from
<https://download.opensuse.org/repositories/Kernel:/HEAD/RISCV/>. The
same kernel with CONFIG_RELOCATABLE disabled is available from
<https://download.opensuse.org/repositories/home:/Andreas_Schwab:/riscv:/kernel/standard/>.

Sorry I missed this earlier, there's been some other reports of boot failures on rc1 showing up but those were all a lot more vague. Just setting CONFIG_RELOCATABLE=y doesn't manifest a boot failure on QEMU on my end and I don't have an UNmatched floating around.

Alex says he's going to look into it (and IIRC he has my Unmatched...).