* Re: [PATCH] powerpc/build: vdso linker warning for orphan sections [not found] <20230609051002.3342-1-npiggin@gmail.com> @ 2023-07-17 19:43 ` John Ogness 2023-07-18 12:59 ` Michael Ellerman 0 siblings, 1 reply; 5+ messages in thread From: John Ogness @ 2023-07-17 19:43 UTC (permalink / raw) To: Nicholas Piggin; +Cc: linuxppc-dev, Michael Ellerman, linux-kernel Hi Nicholas, On 2023-06-09, Nicholas Piggin <npiggin@gmail.com> wrote: > Add --orphan-handlin for vdsos, and adjust vdso linker scripts to deal > with orphan sections. I'm reporting that I am getting a linker warning with 6.5-rc2. The warning message is: ld: warning: discarding dynamic section .rela.opd and bisects to: 8ad57add77d3 ("powerpc/build: vdso linker warning for orphan sections") Despite the warning, my ppc64 system seems to run fine. Let me know if you need any other information from me. I noticed [0] this with 6.5-rc1 but didn't contact the right people. John Ogness [0] https://lore.kernel.org/lkml/871qhf1q3j.fsf@jogness.linutronix.de ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] powerpc/build: vdso linker warning for orphan sections 2023-07-17 19:43 ` [PATCH] powerpc/build: vdso linker warning for orphan sections John Ogness @ 2023-07-18 12:59 ` Michael Ellerman 2023-07-18 14:22 ` John Ogness 0 siblings, 1 reply; 5+ messages in thread From: Michael Ellerman @ 2023-07-18 12:59 UTC (permalink / raw) To: John Ogness, Nicholas Piggin; +Cc: linuxppc-dev, linux-kernel John Ogness <john.ogness@linutronix.de> writes: > Hi Nicholas, > > On 2023-06-09, Nicholas Piggin <npiggin@gmail.com> wrote: >> Add --orphan-handlin for vdsos, and adjust vdso linker scripts to deal >> with orphan sections. > > I'm reporting that I am getting a linker warning with 6.5-rc2. The > warning message is: > > ld: warning: discarding dynamic section .rela.opd > > and bisects to: > > 8ad57add77d3 ("powerpc/build: vdso linker warning for orphan sections") > > Despite the warning, my ppc64 system seems to run fine. Let me know if > you need any other information from me. We already discard .opd and .rela*, so I guess we should also be discarding .rela.opd. Can you test with a newer compiler/binutils? cheers ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] powerpc/build: vdso linker warning for orphan sections 2023-07-18 12:59 ` Michael Ellerman @ 2023-07-18 14:22 ` John Ogness 2023-07-19 11:55 ` Michael Ellerman 0 siblings, 1 reply; 5+ messages in thread From: John Ogness @ 2023-07-18 14:22 UTC (permalink / raw) To: Michael Ellerman, Nicholas Piggin; +Cc: linuxppc-dev, linux-kernel On 2023-07-18, Michael Ellerman <mpe@ellerman.id.au> wrote: >> ld: warning: discarding dynamic section .rela.opd >> >> and bisects to: >> >> 8ad57add77d3 ("powerpc/build: vdso linker warning for orphan sections") > > Can you test with a newer compiler/binutils? Testing the Debian release cross compilers/binutils: Debian 10 / gcc 8.3.0 / ld 2.31.1: generates the warning Debian 11 / gcc 10.2.1 / ld 2.35.2: generates the warning Debian 12 / gcc 12.2.0 / ld 2.40: does _not_ generate the warning I suppose moving to the newer toolchain is the workaround. Although it is a bit unusual to require such a modern toolchain in order to build a kernel without warnings. John Ogness ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] powerpc/build: vdso linker warning for orphan sections 2023-07-18 14:22 ` John Ogness @ 2023-07-19 11:55 ` Michael Ellerman 2023-07-19 17:10 ` John Ogness 0 siblings, 1 reply; 5+ messages in thread From: Michael Ellerman @ 2023-07-19 11:55 UTC (permalink / raw) To: John Ogness, Nicholas Piggin; +Cc: linuxppc-dev, linux-kernel John Ogness <john.ogness@linutronix.de> writes: > On 2023-07-18, Michael Ellerman <mpe@ellerman.id.au> wrote: >>> ld: warning: discarding dynamic section .rela.opd >>> >>> and bisects to: >>> >>> 8ad57add77d3 ("powerpc/build: vdso linker warning for orphan sections") >> >> Can you test with a newer compiler/binutils? > > Testing the Debian release cross compilers/binutils: > > Debian 10 / gcc 8.3.0 / ld 2.31.1: generates the warning > > Debian 11 / gcc 10.2.1 / ld 2.35.2: generates the warning > > Debian 12 / gcc 12.2.0 / ld 2.40: does _not_ generate the warning > > I suppose moving to the newer toolchain is the workaround. Although it > is a bit unusual to require such a modern toolchain in order to build a > kernel without warnings. I didn't mean that you should move to a new toolchain to avoid the warning, I was just curious why you're the only person to see it. I regularly test with a gcc 5.5.0 / ld 2.29 toolchain and gcc 13.1.1 / ld 2.39, and I haven't seen the warning. I tried a bunch of others and can't reproduce it. Can you confirm that this makes the warning go away? cheers diff --git a/arch/powerpc/kernel/vdso/vdso64.lds.S b/arch/powerpc/kernel/vdso/vdso64.lds.S index bda6c8cdd459..286e1597c548 100644 --- a/arch/powerpc/kernel/vdso/vdso64.lds.S +++ b/arch/powerpc/kernel/vdso/vdso64.lds.S @@ -85,7 +85,7 @@ SECTIONS *(.branch_lt) *(.data .data.* .gnu.linkonce.d.* .sdata*) *(.bss .sbss .dynbss .dynsbss) - *(.opd) + *(.opd .rela.opd) *(.glink .iplt .plt .rela*) } } ^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] powerpc/build: vdso linker warning for orphan sections 2023-07-19 11:55 ` Michael Ellerman @ 2023-07-19 17:10 ` John Ogness 0 siblings, 0 replies; 5+ messages in thread From: John Ogness @ 2023-07-19 17:10 UTC (permalink / raw) To: Michael Ellerman, Nicholas Piggin; +Cc: linuxppc-dev, linux-kernel Hi Michael, On 2023-07-19, Michael Ellerman <mpe@ellerman.id.au> wrote: > I regularly test with a gcc 5.5.0 / ld 2.29 toolchain and gcc 13.1.1 / > ld 2.39, and I haven't seen the warning. I tried a bunch of others and > can't reproduce it. I will send my config in a separate email (without the lists in CC). Building the vdso_prepare target is all that is needed. > Can you confirm that this makes the warning go away? > > diff --git a/arch/powerpc/kernel/vdso/vdso64.lds.S b/arch/powerpc/kernel/vdso/vdso64.lds.S > index bda6c8cdd459..286e1597c548 100644 > --- a/arch/powerpc/kernel/vdso/vdso64.lds.S > +++ b/arch/powerpc/kernel/vdso/vdso64.lds.S > @@ -85,7 +85,7 @@ SECTIONS > *(.branch_lt) > *(.data .data.* .gnu.linkonce.d.* .sdata*) > *(.bss .sbss .dynbss .dynsbss) > - *(.opd) > + *(.opd .rela.opd) > *(.glink .iplt .plt .rela*) Hmmm. Not sure what that would change. And indeed it does not make the warning go away. Doing some testing it seems that previously .rela.opd was being silently placed in the .rela.dyn section. So doing that explicitly obviously gets rid of the warning: Index: linux-6.5-rc2/arch/powerpc/kernel/vdso/vdso64.lds.S =================================================================== --- linux-6.5-rc2.orig/arch/powerpc/kernel/vdso/vdso64.lds.S +++ linux-6.5-rc2/arch/powerpc/kernel/vdso/vdso64.lds.S @@ -69,7 +69,7 @@ SECTIONS .eh_frame_hdr : { *(.eh_frame_hdr) } :text :eh_frame_hdr .eh_frame : { KEEP (*(.eh_frame)) } :text .gcc_except_table : { *(.gcc_except_table) } - .rela.dyn ALIGN(8) : { *(.rela.dyn) } + .rela.dyn ALIGN(8) : { *(.rela.dyn) *(.rela.opd) } .got ALIGN(8) : { *(.got .toc) } But if the goal is to get rid of .rela.opd then the question is: why is the linker complaining about it being discarded? John ^ permalink raw reply [flat|nested] 5+ messages in thread
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2023-07-17 19:43 ` [PATCH] powerpc/build: vdso linker warning for orphan sections John Ogness
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2023-07-18 14:22 ` John Ogness
2023-07-19 11:55 ` Michael Ellerman
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