Re: [PATCH] x86/Kconfig: rust: Patchable function Rust compat

From: Martin Rodriguez Reboredo
Date: Mon Dec 11 2023 - 10:47:06 EST


On 12/11/23 12:07, Matthew Maurer wrote:
Rust doesn't yet support patchable entry, but likely will soon. Disable
function padding when Rust is used but doesn't support it, and propagate
the flag when it does.

Signed-off-by: Matthew Maurer <mmaurer@xxxxxxxxxx>
---
[...]
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 1a068de12a56..0228af62742e 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -211,7 +211,9 @@ endif
ifdef CONFIG_CALL_PADDING
PADDING_CFLAGS := -fpatchable-function-entry=$(CONFIG_FUNCTION_PADDING_BYTES),$(CONFIG_FUNCTION_PADDING_BYTES)
+PADDING_RUSTFLAGS := -Zpatchable-function-entry=$(CONFIG_FUNCTION_PADDING_BYTES),$(CONFIG_FUNCTION_PADDING_BYTES)

It seems that at a glance there's no discussion around this, neither an
issue, branch, PR or commit. Do you happen to have a link to it?

KBUILD_CFLAGS += $(PADDING_CFLAGS)
+KBUILD_RUSTFLAGS += $(PADDING_RUSTFLAGS)
export PADDING_CFLAGS
endif