Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Sat, 17 Dec 2022 12:44:34 +0800
In-Reply-To: <20221217044436.4138642-1-davidgow@google.com>
Mime-Version: 1.0
References: <20221217044436.4138642-1-davidgow@google.com>
Message-ID: <20221217044436.4138642-2-davidgow@google.com>
Subject: [PATCH 1/3] rust: arch/um: Use 'pie' relocation mode under UML
From:   David Gow <davidgow@google.com>
To:     Miguel Ojeda <ojeda@kernel.org>,
        "=?UTF-8?q?Bj=C3=B6rn=20Roy=20Baron?=" <bjorn3_gh@protonmail.com>,
        Richard Weinberger <richard@nod.at>,
        Anton Ivanov <anton.ivanov@cambridgegreys.com>,
        Johannes Berg <johannes@sipsolutions.net>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>
Cc:     David Gow <davidgow@google.com>, rust-for-linux@vger.kernel.org,
        linux-um@lists.infradead.org, llvm@lists.linux.dev,
        linux-doc@vger.kernel.org, kunit-dev@googlegroups.com,
        x86@kernel.org, linux-kernel@vger.kernel.org,
        Wedson Almeida Filho <wedsonaf@gmail.com>,
        Gary Guo <gary@garyguo.net>,
        Brendan Higgins <brendan.higgins@linux.dev>,
        Daniel Latypov <dlatypov@google.com>,
        Jonathan Corbet <corbet@lwn.net>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

UML expects a position independent executable for some reason, so tell
rustc to generate pie objects. Otherwise we get a bunch of relocations
we can't deal with in libcore.

Signed-off-by: David Gow <davidgow@google.com>
---
 arch/um/Makefile | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/um/Makefile b/arch/um/Makefile
index f1d4d67157be..ae321282dc6f 100644
--- a/arch/um/Makefile
+++ b/arch/um/Makefile
@@ -68,6 +68,8 @@ KBUILD_CFLAGS += $(CFLAGS) $(CFLAGS-y) -D__arch_um__ \
 	-Din6addr_loopback=kernel_in6addr_loopback \
 	-Din6addr_any=kernel_in6addr_any -Dstrrchr=kernel_strrchr
 
+KBUILD_RUSTFLAGS += -Crelocation-model=pie
+
 KBUILD_AFLAGS += $(ARCH_INCLUDE)
 
 USER_CFLAGS = $(patsubst $(KERNEL_DEFINES),,$(patsubst -I%,,$(KBUILD_CFLAGS))) \
-- 
2.39.0.314.g84b9a713c41-goog