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From:   Ricardo Ribalda <ribalda@chromium.org>
Date:   Fri, 19 May 2023 16:47:39 +0200
Subject: [PATCH v7 4/4] riscv/purgatory: Remove PGO flags
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Message-Id: <20230321-kexec_clang16-v7-4-b05c520b7296@chromium.org>
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To:     Eric Biederman <ebiederm@xmission.com>,
        Philipp Rudo <prudo@linux.vnet.ibm.com>,
        Dave Young <dyoung@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>, x86@kernel.org,
        "H. Peter Anvin" <hpa@zytor.com>,
        Nathan Chancellor <nathan@kernel.org>,
        Tom Rix <trix@redhat.com>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Nicholas Piggin <npiggin@gmail.com>,
        Christophe Leroy <christophe.leroy@csgroup.eu>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>
Cc:     Baoquan He <bhe@redhat.com>, Philipp Rudo <prudo@redhat.com>,
        kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
        Ross Zwisler <zwisler@google.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Simon Horman <horms@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        llvm@lists.linux.dev, linuxppc-dev@lists.ozlabs.org,
        linux-riscv@lists.infradead.org,
        Ricardo Ribalda <ribalda@chromium.org>, stable@vger.kernel.org,
        Palmer Dabbelt <palmer@rivosinc.com>
Precedence: bulk

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")
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
---
 arch/riscv/purgatory/Makefile | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/riscv/purgatory/Makefile b/arch/riscv/purgatory/Makefile
index 5730797a6b40..bd2e27f82532 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-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