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From:   Song Shuai <songshuaishuai@tinylab.org>
To:     paul.walmsley@sifive.com, palmer@dabbelt.com,
        aou@eecs.berkeley.edu, conor.dooley@microchip.com,
        lihuafei1@huawei.com, songshuaishuai@tinylab.org,
        petr.tesarik.ext@huawei.com, duwe@suse.de, ribalda@chromium.org,
        akpm@linux-foundation.org, keescook@chromium.org, hi@alyssa.is,
        heiko@sntech.de, alexghiti@rivosinc.com, schwab@suse.de
Cc:     linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
        kexec@lists.infradead.org
Subject: [PATCH 2/2] riscv: kexec: Remove -fPIE for PURGATORY_CFLAGS
Date:   Wed, 11 Oct 2023 16:31:32 +0800
Message-Id: <20231011083132.2428720-3-songshuaishuai@tinylab.org>
In-Reply-To: <20231011083132.2428720-1-songshuaishuai@tinylab.org>
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With CONFIG_RELOCATABLE enabled, KBUILD_CFLAGS had a -fPIE option
and then the purgatory/string.o was built to reference _ctype symbol
via R_RISCV_GOT_HI20 relocations which can't be handled by purgatory.

As a consequence, the kernel failed kexec_load_file() with:

[  880.386562] kexec_image: The entry point of kernel at 0x80200000
[  880.388650] kexec_image: Unknown rela relocation: 20
[  880.389173] kexec_image: Error loading purgatory ret=-8

So remove the -fPIE option for PURGATORY_CFLAGS to generate
R_RISCV_PCREL_HI20 relocations type making puragtory work as it was.

Fixes: 39b33072941f ("riscv: Introduce CONFIG_RELOCATABLE")
Signed-off-by: Song Shuai <songshuaishuai@tinylab.org>
---
 arch/riscv/purgatory/Makefile | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/riscv/purgatory/Makefile b/arch/riscv/purgatory/Makefile
index 9e6476719abb..982fc8e77108 100644
--- a/arch/riscv/purgatory/Makefile
+++ b/arch/riscv/purgatory/Makefile
@@ -81,6 +81,10 @@ ifdef CONFIG_CFI_CLANG
 PURGATORY_CFLAGS_REMOVE		+= $(CC_FLAGS_CFI)
 endif
 
+ifdef CONFIG_RELOCATABLE
+PURGATORY_CFLAGS_REMOVE		+= -fPIE
+endif
+
 CFLAGS_REMOVE_purgatory.o	+= $(PURGATORY_CFLAGS_REMOVE)
 CFLAGS_purgatory.o		+= $(PURGATORY_CFLAGS)
 
-- 
2.20.1