On 2024-11-12 06:38, Rong Xu wrote:
I compared the System.map files from Klara Modin. The linker script is
doing what I expected: relocating the unlikely executed functions to the
beginning of the .text section.
However, the problem is with the _stext symbol. It belongs to the
.text section, so
it is positioned after the unlikely (or hot) functions. But it really
needs to be
the start of the text section.
I checked all vmlinux.lds.S in arch/, I found that most archs
explicitly assign _stext to the same address as _text, with the
following 3 exceptions:
arch/sh/kernel/vmlinux.lds.S
arch/mips/kernel/vmlinux.lds.S
arch/sparc/kernel/vmlinux.lds.S
Note that we already partially handled arch/sparc/kernel/vmlinux.lds.S
for sparc64.
But we need to handle sparc32 also.
Additionally, the boot/compressed/vmlinux.lds.S also the TEXT_TEXT
template. However,
I presume these files do not generate the .text.unlikely. or
.text.hot.* sections.
I sent the following patch to Klara because I don't have an
environment to build and test.
====================
diff --git a/arch/mips/kernel/vmlinux.lds.S b/arch/mips/kernel/vmlinux.lds.S
index 9ff55cb80a64..5f130af44247 100644
--- a/arch/mips/kernel/vmlinux.lds.S
+++ b/arch/mips/kernel/vmlinux.lds.S
@@ -61,6 +61,7 @@ SECTIONS
/* read-only */
_text = .; /* Text and read-only data */
.text : {
+ _stext = .;
TEXT_TEXT
SCHED_TEXT
LOCK_TEXT
======================
If Klara confirms the fix, I will send the patch for review.
Thanks,
-Rong
This does indeed fix the issue for me.
Thanks,
Tested-by: Klara Modin <klarasmodin@xxxxxxxxx>
