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Sun, 04 Oct 2026 16:48:29 -0700 (PDT) Received: from ryzen.lan ([2601:644:8000:7a86::e35]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2e49f6cd764sm26207215ad.48.2026.10.04.16.48.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 04 Oct 2026 16:48:29 -0700 (PDT) From: Rosen Penev To: linux-mips@vger.kernel.org Cc: Thomas Bogendoerfer , Nathan Chancellor , Nick Desaulniers , Bill Wendling , Justin Stitt , Paul Burton , linux-kernel@vger.kernel.org (open list), llvm@lists.linux.dev (open list:CLANG/LLVM BUILD SUPPORT:Keyword:\b(?i:clang|llvm)\b) Subject: [PATCH] MIPS: Avoid dead code/data elimination when using recordmcount Date: Sun, 4 Oct 2026 16:48:26 -0700 Message-ID: <20261004234826.541468-1-rosenp@gmail.com> X-Mailer: git-send-email 2.56.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit CONFIG_LD_DEAD_CODE_DATA_ELIMINATION builds with -ffunction-sections, placing every function in its own section. recordmcount refuses to use weak symbols as section bases, as a strong definition could override them, so a weak function alone in its section, such as the generic pcibios_fixup_bus() stub, breaks the build: Cannot find symbol for section 88: .text.pcibios_fixup_bus. drivers/pci/probe.o: failed MIPS always records mcount locations with recordmcount, so this hits any config with the function tracer and dead code elimination enabled, e.g. malta_defconfig built with LLVM=1. Only offer dead code elimination when recordmcount is not used, as powerpc does since commit f8b2336f15f3 ("powerpc: Avoid dead code/data elimination when using recordmcount"). In practice this makes it unavailable together with the function tracer on MIPS. Fixes: c0436b503591 ("MIPS: Enable dead code elimination") Signed-off-by: Rosen Penev --- arch/mips/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig index ddabe25d6bf7..f4f82bd75b66 100644 --- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig @@ -79,7 +79,7 @@ config MIPS select HAVE_IRQ_TIME_ACCOUNTING select HAVE_KPROBES select HAVE_KRETPROBES - select HAVE_LD_DEAD_CODE_DATA_ELIMINATION + select HAVE_LD_DEAD_CODE_DATA_ELIMINATION if !FTRACE_MCOUNT_USE_RECORDMCOUNT select HAVE_MOD_ARCH_SPECIFIC select HAVE_NMI select HAVE_PAGE_SIZE_4KB if !CPU_LOONGSON2EF && !CPU_LOONGSON64 -- 2.56.0