On 7/7/2025 1:03 AM, Kirill A. Shutemov wrote:
> From: Sohil Mehta <sohil.mehta@xxxxxxxxx>
>
> For patching, the kernel initializes a temporary mm area in the lower
> half of the address range. See commit 4fc19708b165 ("x86/alternatives:
> Initialize temporary mm for patching").
>
> Disable LASS enforcement during patching to avoid triggering a #GP
> fault.
>
> The objtool warns due to a call to a non-allowed function that exists
> outside of the stac/clac guard, or references to any function with a
> dynamic function pointer inside the guard. See the Objtool warnings
> section #9 in the document tools/objtool/Documentation/objtool.txt.
>
> Considering that patching is usually small, replace the memcpy() and
> memset() functions in the text poking functions with their open coded
> versions.
>
> Signed-off-by: Sohil Mehta <sohil.mehta@xxxxxxxxx>
> Signed-off-by: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Kirill, it might be worth adding your co-developed-by tag. The patch has
more changes than I can claim credit for.
> ---
> arch/x86/include/asm/smap.h | 33 +++++++++++++++++++++++++++++++--
> arch/x86/kernel/alternative.c | 28 ++++++++++++++++++++++++++--
> 2 files changed, 57 insertions(+), 4 deletions(-)
>
