Messages in this thread | | | Date | Thu, 27 Jul 2023 11:55:30 +0100 | From | Joey Gouly <> | Subject | Re: [PATCH] arm64: vdso: remove two .altinstructions related symbols |
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Hi,
On Thu, Jul 27, 2023 at 11:19:27AM +0100, Will Deacon wrote: > On Thu, Jul 27, 2023 at 01:36:19AM +0800, Jisheng Zhang wrote: > > The two symbols __alt_instructions and __alt_instructions_end are not > > used, remove them. > > > > Signed-off-by: Jisheng Zhang <jszhang@kernel.org> > > --- > > arch/arm64/kernel/vdso/vdso.lds.S | 2 -- > > 1 file changed, 2 deletions(-) > > > > diff --git a/arch/arm64/kernel/vdso/vdso.lds.S b/arch/arm64/kernel/vdso/vdso.lds.S > > index 6028f1fe2d1c..45354f2ddf70 100644 > > --- a/arch/arm64/kernel/vdso/vdso.lds.S > > +++ b/arch/arm64/kernel/vdso/vdso.lds.S > > @@ -50,9 +50,7 @@ SECTIONS > > > > . = ALIGN(4); > > .altinstructions : { > > - __alt_instructions = .; > > *(.altinstructions) > > - __alt_instructions_end = .; > > } > > If we don't need the symbols, then why do we need this section at all?
Looks like it was a copy/paste from my commit 4e3bca8f7cdd ("arm64: alternative: patch alternatives in the vDSO"). The VDSO patching code searches for a section named '.altinstructions' by reading the VDSO as an ELF file, and doesn't use the __alt_instructions / __alt_instructions_end symbols. The kernel patching code uses the __alt_instructions symbol (from the vmlinux.ld.S linker script).
So it's safe to remove these, but the section itself needs to stay.
Thanks, Joey
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