Re: [PATCH master v2 0/3] Fix GCC 11 THUMB2 relocate_to_current_adr miscompile

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

On 20.10.22 15:15, Ahmad Fatoum wrote:
> Since a8b788ba61eb ("relocate_to_current_adr: hang directly on error instead
> of panic()"),  GCC can prove that variables aren't supposed to overlap and as
> such it generated code than readded get_runtime_offset() on top of an
> already relocated linker-defined variable's address.
> See PATCH 2/3 for a disassembly of the affected code. Board code can
> be similarly micompiled, but that's a fix for another day.

v1 -> v2:
  - rename get_unrelocated() to runtime_address()
  - add Fixes: line after identifying why this issue only popped up now:
    removing panic() in relocate_to_current_adr() shifted code around
    enough for compiler to consider optimization worthwhile
  - fixed left-over + offset in RISC-V patch

> 
> Ahmad Fatoum (3):
>   include: asm-generic: reloc: implement runtime_address()
>   ARM: cpu: add compiler barrier around unrelocated access
>   RISC-V: add compiler barriers around unrelocated accesses
> 
>  arch/arm/cpu/common.c             | 15 ++++---
>  arch/arm/cpu/uncompress.c         |  4 +-
>  arch/riscv/boot/uncompress.c      |  4 +-
>  arch/riscv/include/asm/sections.h |  3 +-
>  arch/riscv/lib/reloc.c            | 10 +++--
>  include/asm-generic/reloc.h       | 69 +++++++++++++++++++++++++++++++
>  6 files changed, 91 insertions(+), 14 deletions(-)
> 


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