| Message ID | 20210104204850.990966-1-natechancellor@gmail.com |
|---|---|
| State | Accepted |
| Commit | 3ce47d95b7346dcafd9bed3556a8d072cb2b8571 |
| Headers | show |
| Series | powerpc: Handle .text.{hot,unlikely}.* in linker script | expand |
On Mon, 4 Jan 2021 13:59:53 -0700, Nathan Chancellor wrote: > Commit eff8728fe698 ("vmlinux.lds.h: Add PGO and AutoFDO input > sections") added ".text.unlikely.*" and ".text.hot.*" due to an LLVM > change [1]. > > After another LLVM change [2], these sections are seen in some PowerPC > builds, where there is a orphan section warning then build failure: > > [...] Applied to powerpc/fixes. [1/1] powerpc: Handle .text.{hot,unlikely}.* in linker script https://git.kernel.org/powerpc/c/3ce47d95b7346dcafd9bed3556a8d072cb2b8571 cheers
Hi! Very late of course, and the patch is fine, but: On Mon, Jan 04, 2021 at 01:59:53PM -0700, Nathan Chancellor wrote: > Commit eff8728fe698 ("vmlinux.lds.h: Add PGO and AutoFDO input > sections") added ".text.unlikely.*" and ".text.hot.*" due to an LLVM > change [1]. > > After another LLVM change [2], these sections are seen in some PowerPC > builds, where there is a orphan section warning then build failure: > > $ make -skj"$(nproc)" \ > ARCH=powerpc CROSS_COMPILE=powerpc64le-linux-gnu- LLVM=1 O=out \ > distclean powernv_defconfig zImage.epapr > ld.lld: warning: kernel/built-in.a(panic.o):(.text.unlikely.) is being placed in '.text.unlikely.' Is the section really called ".text.unlikely.", i.e. the name ending in a dot? How very unusual, is there some bug elsewhere? Segher
On Sat, Jan 16, 2021 at 12:44:38PM -0600, Segher Boessenkool wrote: > Hi! > > Very late of course, and the patch is fine, but: > > On Mon, Jan 04, 2021 at 01:59:53PM -0700, Nathan Chancellor wrote: > > Commit eff8728fe698 ("vmlinux.lds.h: Add PGO and AutoFDO input > > sections") added ".text.unlikely.*" and ".text.hot.*" due to an LLVM > > change [1]. > > > > After another LLVM change [2], these sections are seen in some PowerPC > > builds, where there is a orphan section warning then build failure: > > > > $ make -skj"$(nproc)" \ > > ARCH=powerpc CROSS_COMPILE=powerpc64le-linux-gnu- LLVM=1 O=out \ > > distclean powernv_defconfig zImage.epapr > > ld.lld: warning: kernel/built-in.a(panic.o):(.text.unlikely.) is being placed in '.text.unlikely.' > > Is the section really called ".text.unlikely.", i.e. the name ending in > a dot? How very unusual, is there some bug elsewhere? No, this was an intention change done by LLVM: https://reviews.llvm.org/D79600 Cheers, Nathan
diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S index 0318ba436f34..8e0b1298bf19 100644 --- a/arch/powerpc/kernel/vmlinux.lds.S +++ b/arch/powerpc/kernel/vmlinux.lds.S @@ -85,7 +85,7 @@ SECTIONS ALIGN_FUNCTION(); #endif /* careful! __ftr_alt_* sections need to be close to .text */ - *(.text.hot TEXT_MAIN .text.fixup .text.unlikely .fixup __ftr_alt_* .ref.text); + *(.text.hot .text.hot.* TEXT_MAIN .text.fixup .text.unlikely .text.unlikely.* .fixup __ftr_alt_* .ref.text); #ifdef CONFIG_PPC64 *(.tramp.ftrace.text); #endif
Commit eff8728fe698 ("vmlinux.lds.h: Add PGO and AutoFDO input sections") added ".text.unlikely.*" and ".text.hot.*" due to an LLVM change [1]. After another LLVM change [2], these sections are seen in some PowerPC builds, where there is a orphan section warning then build failure: $ make -skj"$(nproc)" \ ARCH=powerpc CROSS_COMPILE=powerpc64le-linux-gnu- LLVM=1 O=out \ distclean powernv_defconfig zImage.epapr ld.lld: warning: kernel/built-in.a(panic.o):(.text.unlikely.) is being placed in '.text.unlikely.' ... ld.lld: warning: address (0xc000000000009314) of section .text is not a multiple of alignment (256) ... ERROR: start_text address is c000000000009400, should be c000000000008000 ERROR: try to enable LD_HEAD_STUB_CATCH config option ERROR: see comments in arch/powerpc/tools/head_check.sh ... Explicitly handle these sections like in the main linker script so there is no more build failure. Cc: stable@vger.kernel.org Fixes: 83a092cf95f2 ("powerpc: Link warning for orphan sections") Link: https://github.com/ClangBuiltLinux/linux/issues/1218 Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> --- arch/powerpc/kernel/vmlinux.lds.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) base-commit: d8a4f20584d5906093a8fc6aa06622102a501095