Thread (11 messages) 11 messages, 3 authors, 2023-09-08
STALE1020d
Revisions (2)
  1. v6 [diff vs current]
  2. v7 current

[PATCH v7 2/4] x86/purgatory: Remove PGO flags

From: Ricardo Ribalda <hidden>
Date: 2023-05-19 14:48:44
Also in: kexec, linux-riscv, lkml, llvm, stable
Subsystem: the rest, x86 architecture (32-bit and 64-bit) · Maintainers: Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen

If profile-guided optimization 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>
---
 arch/x86/purgatory/Makefile | 5 +++++
 1 file changed, 5 insertions(+)
diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile
index 82fec66d46d2..42abd6af1198 100644
--- a/arch/x86/purgatory/Makefile
+++ b/arch/x86/purgatory/Makefile
@@ -14,6 +14,11 @@ $(obj)/sha256.o: $(srctree)/lib/crypto/sha256.c FORCE
 
 CFLAGS_sha256.o := -D__DISABLE_EXPORTS
 
+# When profile-guided 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
-- 
2.40.1.698.g37aff9b760-goog
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