[v5,03/23] arm64: Build vDSO with -ffixed-x18

Message ID	20190222122430.21180-4-vincenzo.frascino@arm.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org> From: Vincenzo Frascino <vincenzo.frascino@arm.com> To: linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH v5 03/23] arm64: Build vDSO with -ffixed-x18 Date: Fri, 22 Feb 2019 12:24:10 +0000 Message-Id: <20190222122430.21180-4-vincenzo.frascino@arm.com> In-Reply-To: <20190222122430.21180-1-vincenzo.frascino@arm.com> References: <20190222122430.21180-1-vincenzo.frascino@arm.com> MIME-Version: 1.0 Precedence: list Cc: Shuah Khan <shuah@kernel.org>, Arnd Bergmann <arnd@arndb.de>, Catalin Marinas <catalin.marinas@arm.com>, Daniel Lezcano <daniel.lezcano@linaro.org>, Will Deacon <will.deacon@arm.com>, Russell King <linux@armlinux.org.uk>, Ralf Baechle <ralf@linux-mips.org>, Mark Salyzyn <salyzyn@android.com>, Paul Burton <paul.burton@mips.com>, Dmitry Safonov <0x7f454c46@gmail.com>, Rasmus Villemoes <linux@rasmusvillemoes.dk>, Thomas Gleixner <tglx@linutronix.de>, Peter Collingbourne <pcc@google.com>, Mark Salyzyn <salyzyn@google.com> Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" <linux-arm-kernel-bounces@lists.infradead.org> Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org
Series	Unify vDSOs across more architectures \| expand [v5,00/23] Unify vDSOs across more architectures [v5,01/23] kernel: Standardize vdso_datapage [v5,02/23] kernel: Define gettimeofday vdso common code [v5,03/23] arm64: Build vDSO with -ffixed-x18 [v5,04/23] arm64: Substitute gettimeofday with C implementation [v5,05/23] arm64: compat: Alloc separate pages for vectors and sigpage [v5,06/23] arm64: compat: Split kuser32 [v5,07/23] arm64: compat: Refactor aarch32_alloc_vdso_pages() [v5,08/23] arm64: compat: Add KUSER_HELPERS config option [v5,09/23] arm64: compat: Add missing syscall numbers [v5,10/23] arm64: compat: Expose signal related structures [v5,11/23] arm64: compat: Generate asm offsets for signals [v5,12/23] lib: vdso: Add compat support [v5,13/23] arm64: compat: Add vDSO [v5,14/23] arm64: Refactor vDSO code [v5,15/23] arm64: compat: vDSO setup for compat layer [v5,16/23] arm64: elf: vDSO code page discovery [v5,17/23] arm64: compat: Get sigreturn trampolines from vDSO [v5,18/23] arm64: Add vDSO compat support [v5,19/23] arm64: Enable compat vDSO support [v5,20/23] arm: Add support for generic vDSO [v5,21/23] mips: Add support for generic vDSO [v5,22/23] x86: Add support for generic vDSO [v5,23/23] kselftest: Extend vDSO selftest

Message ID

20190222122430.21180-4-vincenzo.frascino@arm.com (mailing list archive)

State

New, archived

Headers

From: Vincenzo Frascino <vincenzo.frascino@arm.com>
To: linux-arch@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH v5 03/23] arm64: Build vDSO with -ffixed-x18
Date: Fri, 22 Feb 2019 12:24:10 +0000
Message-Id: <20190222122430.21180-4-vincenzo.frascino@arm.com>
In-Reply-To: <20190222122430.21180-1-vincenzo.frascino@arm.com>
References: <20190222122430.21180-1-vincenzo.frascino@arm.com>
MIME-Version: 1.0
Precedence: list
Cc: Shuah Khan <shuah@kernel.org>, Arnd Bergmann <arnd@arndb.de>,
 Catalin Marinas <catalin.marinas@arm.com>,
 Daniel Lezcano <daniel.lezcano@linaro.org>,
 Will Deacon <will.deacon@arm.com>,
 Russell King <linux@armlinux.org.uk>, Ralf Baechle <ralf@linux-mips.org>,
 Mark Salyzyn <salyzyn@android.com>, Paul Burton <paul.burton@mips.com>,
 Dmitry Safonov <0x7f454c46@gmail.com>,
 Rasmus Villemoes <linux@rasmusvillemoes.dk>,
 Thomas Gleixner <tglx@linutronix.de>, Peter Collingbourne <pcc@google.com>,
 Mark Salyzyn <salyzyn@google.com>
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 linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org

Series

Unify vDSOs across more architectures | expand

Commit Message

Vincenzo Frascino Feb. 22, 2019, 12:24 p.m. UTC

From: Peter Collingbourne <pcc@google.com>

The vDSO needs to be build with x18 reserved in order to accommodate
userspace platform ABIs built on top of Linux that use the register
to carry inter-procedural state, as provided for by the AAPCS.
An example of such a platform ABI is the one that will be used by an
upcoming version of Android.

Although this change is currently a no-op due to the fact that the vDSO
is currently implemented in pure assembly on arm64, it is necessary
in order to prepare for another change [1] that will add C code to
the vDSO.

[1] https://patchwork.kernel.org/patch/10044501/

Signed-off-by: Peter Collingbourne <pcc@google.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Mark Salyzyn <salyzyn@google.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
---
 arch/arm64/kernel/vdso/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile
index b215c712d897..8cd4707f832a 100644
--- a/arch/arm64/kernel/vdso/Makefile
+++ b/arch/arm64/kernel/vdso/Makefile
@@ -12,7 +12,7 @@  obj-vdso := gettimeofday.o note.o sigreturn.o
 targets := $(obj-vdso) vdso.so vdso.so.dbg
 obj-vdso := $(addprefix $(obj)/, $(obj-vdso))
 
-ccflags-y := -shared -fno-common -fno-builtin
+ccflags-y := -shared -fno-common -fno-builtin -ffixed-x18
 ccflags-y += -nostdlib -Wl,-soname=linux-vdso.so.1 \
 		$(call cc-ldoption, -Wl$(comma)--hash-style=sysv)

[v5,03/23] arm64: Build vDSO with -ffixed-x18

Commit Message

Patch