Re: [PATCH v6 4/4] risc/purgatory: Add linker script

On Mon, May 01, 2023 at 07:18:12PM +0200, Ricardo Ribalda wrote:

On Mon, 1 May 2023 at 18:19, Nick Desaulniers [off-list ref] wrote:

quoted

On Mon, May 1, 2023 at 5:39 AM Ricardo Ribalda [off-list ref] wrote:

quoted

If PGO is enabled, the purgatory ends up with multiple .text sections.
This is not supported by kexec and crashes the system.

Cc: stable@vger.kernel.org
Fixes: 930457057abe ("kernel/kexec_file.c: split up __kexec_load_puragory")
Signed-off-by: Ricardo Ribalda <redacted>

Hi Ricardo,
Thanks for the series.  Does this patch 4/4 need a new online commit
description? It's not adding a linker script (maybe an earlier version
was).

Thanks for catching this. It should have said

risc/purgatory: Remove profile optimization flags

     ^^
Perhaps with the omitted v added too?

Also while playing the $subject nitpicking game, is it not called
"profile**-guided** optimisation" (and ditto in the comments)?

Cheers,
Conor.

Will fix it on my local branch in case there is a next version of the
series. Otherwise, please the maintainer fix the subject.

quoted

quoted

---
 arch/riscv/purgatory/Makefile | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/riscv/purgatory/Makefile b/arch/riscv/purgatory/Makefile
index 5730797a6b40..cf3a44121a90 100644
--- a/arch/riscv/purgatory/Makefile
+++ b/arch/riscv/purgatory/Makefile

@@ -35,6 +35,11 @@ CFLAGS_sha256.o := -D__DISABLE_EXPORTS
 CFLAGS_string.o := -D__DISABLE_EXPORTS
 CFLAGS_ctype.o := -D__DISABLE_EXPORTS

+# When profile optimization is enabled, llvm emits two different overlapping
+# text sections, which is not supported by kexec. Remove profile optimization
+# flags.
+KBUILD_CFLAGS := $(filter-out -fprofile-sample-use=% -fprofile-use=%,$(KBUILD_CFLAGS))
+
 # When linking purgatory.ro with -r unresolved symbols are not checked,
 # also link a purgatory.chk binary without -r to check for unresolved symbols.
 PURGATORY_LDFLAGS := -e purgatory_start -z nodefaultlib

--

2.40.1.495.gc816e09b53d-goog

--
Thanks,
~Nick Desaulniers

-- 
Ricardo Ribalda

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