linux-kernel - [PATCH] riscv: disable generation of unwind tables

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Message-ID: <mvmzg9xybqu.fsf@suse.de>
Date:   Wed, 01 Feb 2023 10:29:45 +0100
From:   Andreas Schwab <schwab@...e.de>
To:     linux-riscv@...ts.infradead.org
Cc:     Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>, linux-kernel@...r.kernel.org
Subject: [PATCH] riscv: disable generation of unwind tables

GCC 13 will enable -fasynchronous-unwind-tables by default on riscv.  In
the kernel, we don't have any use for unwind tables yet, so disable them.
More importantly, the .eh_frame section brings relocations
(R_RISC_32_PCREL, R_RISCV_SET{6,8,16}, R_RISCV_SUB{6,8,16}) into modules
that we are not prepared to handle.

Signed-off-by: Andreas Schwab <schwab@...e.de>
---
 arch/riscv/Makefile | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile
index faf2c2177094..82153960ac00 100644
--- a/arch/riscv/Makefile
+++ b/arch/riscv/Makefile
@@ -80,6 +80,9 @@ ifeq ($(CONFIG_PERF_EVENTS),y)
         KBUILD_CFLAGS += -fno-omit-frame-pointer
 endif
 
+# Avoid generating .eh_frame sections.
+KBUILD_CFLAGS += -fno-asynchronous-unwind-tables -fno-unwind-tables
+
 KBUILD_CFLAGS_MODULE += $(call cc-option,-mno-relax)
 KBUILD_AFLAGS_MODULE += $(call as-option,-Wa$(comma)-mno-relax)
 
-- 
2.39.1


-- 
Andreas Schwab, SUSE Labs, schwab@...e.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."