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From: Khem Raj <raj.khem@gmail.com>
To: linux-riscv@lists.infradead.org, clang-built-linux@googlegroups.com
Cc: Khem Raj <raj.khem@gmail.com>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Nathan Chancellor <nathan@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>
Subject: [PATCH] riscv: Use -mno-relax when using lld linker
Date: Fri, 14 May 2021 13:56:43 -0700	[thread overview]
Message-ID: <20210514205643.383422-1-raj.khem@gmail.com> (raw)

lld does not implement the RISCV relaxation optimizations like GNU ld
therefore disable it when building with LLVM=1, Also pass it to
assembler when using external GNU assembler ( LLVM_IAS != 1 ), this
ensures that relevant assembler option is also enabled along. if these
options are not used then we see following relocations in objects

0000000000000000 R_RISCV_ALIGN     *ABS*+0x0000000000000002

These are then rejected by lld
ld.lld: error: capability.c:(.fixup+0x0): relocation R_RISCV_ALIGN requires unimplemented linker relaxation; recompile with -mno-relax but the .o is already compiled with -mno-relax

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
---
 arch/riscv/Makefile | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile
index 3eb9590a0775..519f133e0d53 100644
--- a/arch/riscv/Makefile
+++ b/arch/riscv/Makefile
@@ -38,6 +38,15 @@ else
 	KBUILD_LDFLAGS += -melf32lriscv
 endif
 
+ifeq ($(LLVM),1)
+	KBUILD_CFLAGS += -mno-relax
+	KBUILD_AFLAGS += -mno-relax
+ifneq ($(LLVM_IAS),1)
+	KBUILD_CFLAGS += -Wa,-mno-relax
+	KBUILD_AFLAGS += -Wa,-mno-relax
+endif
+endif
+
 # ISA string setting
 riscv-march-$(CONFIG_ARCH_RV32I)	:= rv32ima
 riscv-march-$(CONFIG_ARCH_RV64I)	:= rv64ima
-- 
2.31.1


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             reply	other threads:[~2021-05-14 20:57 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-14 20:56 Khem Raj [this message]
2021-05-14 21:14 ` [PATCH] riscv: Use -mno-relax when using lld linker Nathan Chancellor
2021-05-14 21:14 ` Fāng-ruì Sòng
2021-05-29 18:40 ` Palmer Dabbelt
2021-05-29 18:42   ` Palmer Dabbelt

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