From: Vincenzo Frascino <vincenzo.frascino@arm.com>
To: linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org,
linux-mm@kvack.org, linux-arch@vger.kernel.org,
linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Robin Murphy <robin.murphy@arm.com>,
Kees Cook <keescook@chromium.org>,
Kate Stewart <kstewart@linuxfoundation.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Ingo Molnar <mingo@kernel.org>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
Shuah Khan <shuah@kernel.org>,
Chintan Pandya <cpandya@codeaurora.org>,
Jacob Bramley <Jacob.Bramley@arm.com>,
Ruben Ayrapetyan <Ruben.Ayrapetyan@arm.com>,
Andrey Konovalov <andreyknvl@google.com>,
Lee Smith <Lee.Smith@arm.com>, Kostya Serebryany <kcc@google.com>,
Dmitry Vyukov <dvyukov@google.com>,
Ramana Radhakrishnan <Ramana.Radhakrishnan@arm.com>,
Luc Van Oostenryck <luc.vanoostenryck@gmail.com>,
Evgeniy Stepanov <eugenis@google.com>,
Alexander Viro <viro@zeniv.linux.org.uk>
Subject: [RFC][PATCH 3/3] arm64: elf: Advertise relaxed ABI
Date: Mon, 10 Dec 2018 14:30:44 +0000 [thread overview]
Message-ID: <20181210143044.12714-4-vincenzo.frascino@arm.com> (raw)
In-Reply-To: <20181210143044.12714-1-vincenzo.frascino@arm.com>
On arm64 the TCR_EL1.TBI0 bit has been set since Linux 3.x hence
the userspace (EL0) is allowed to set a non-zero value in the top
byte but the resulting pointers are not allowed at the user-kernel
syscall ABI boundary.
This patch sets ARM64_AT_FLAGS_SYSCALL_TBI (bit[0]) in the AT_FLAGS
to advertise the relaxation of the ABI to the userspace.
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
CC: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
---
arch/arm64/include/asm/atflags.h | 7 +++++++
arch/arm64/include/asm/elf.h | 5 +++++
arch/arm64/include/uapi/asm/atflags.h | 8 ++++++++
3 files changed, 20 insertions(+)
create mode 100644 arch/arm64/include/asm/atflags.h
create mode 100644 arch/arm64/include/uapi/asm/atflags.h
diff --git a/arch/arm64/include/asm/atflags.h b/arch/arm64/include/asm/atflags.h
new file mode 100644
index 000000000000..b20093d61bf2
--- /dev/null
+++ b/arch/arm64/include/asm/atflags.h
@@ -0,0 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __ASM_ATFLAGS_H
+#define __ASM_ATFLAGS_H
+
+#include <uapi/asm/atflags.h>
+
+#endif
diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h
index 433b9554c6a1..da5a6d310ff4 100644
--- a/arch/arm64/include/asm/elf.h
+++ b/arch/arm64/include/asm/elf.h
@@ -16,6 +16,7 @@
#ifndef __ASM_ELF_H
#define __ASM_ELF_H
+#include <asm/atflags.h>
#include <asm/hwcap.h>
/*
@@ -163,6 +164,10 @@ do { \
NEW_AUX_ENT(AT_IGNORE, 0); \
} while (0)
+/* Platform specific AT_FLAGS */
+#define ELF_AT_FLAGS ARM64_AT_FLAGS_SYSCALL_TBI
+#define COMPAT_ELF_AT_FLAGS 0
+
#define ARCH_HAS_SETUP_ADDITIONAL_PAGES
struct linux_binprm;
extern int arch_setup_additional_pages(struct linux_binprm *bprm,
diff --git a/arch/arm64/include/uapi/asm/atflags.h b/arch/arm64/include/uapi/asm/atflags.h
new file mode 100644
index 000000000000..1cf25692ffd6
--- /dev/null
+++ b/arch/arm64/include/uapi/asm/atflags.h
@@ -0,0 +1,8 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __UAPI_ASM_ATFLAGS_H
+#define __UAPI_ASM_ATFLAGS_H
+
+/* Platform specific AT_FLAGS */
+#define ARM64_AT_FLAGS_SYSCALL_TBI (1 << 0)
+
+#endif
--
2.19.2
next prev parent reply other threads:[~2018-12-10 14:31 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-10 12:50 [PATCH v9 0/8] arm64: untag user pointers passed to the kernel Andrey Konovalov
2018-12-10 12:50 ` [PATCH v9 1/8] arm64: add type casts to untagged_addr macro Andrey Konovalov
2018-12-10 12:50 ` [PATCH v9 2/8] uaccess: add untagged_addr definition for other arches Andrey Konovalov
2018-12-10 12:51 ` [PATCH v9 3/8] arm64: untag user addresses in access_ok and __uaccess_mask_ptr Andrey Konovalov
2018-12-10 12:51 ` [PATCH v9 4/8] mm, arm64: untag user addresses in mm/gup.c Andrey Konovalov
2018-12-10 12:51 ` [PATCH v9 5/8] lib, arm64: untag addrs passed to strncpy_from_user and strnlen_user Andrey Konovalov
2018-12-10 12:51 ` [PATCH v9 6/8] fs, arm64: untag user address in copy_mount_options Andrey Konovalov
2018-12-10 12:51 ` [PATCH v9 7/8] arm64: update Documentation/arm64/tagged-pointers.txt Andrey Konovalov
2018-12-10 12:51 ` [PATCH v9 8/8] selftests, arm64: add a selftest for passing tagged pointers to kernel Andrey Konovalov
2018-12-10 14:30 ` [RFC][PATCH 0/3] arm64 relaxed ABI Vincenzo Frascino
2018-12-10 14:30 ` [RFC][PATCH 1/3] elf: Make AT_FLAGS arch configurable Vincenzo Frascino
2018-12-10 14:30 ` [RFC][PATCH 2/3] arm64: Define Documentation/arm64/elf_at_flags.txt Vincenzo Frascino
2018-12-12 17:34 ` Dave Martin
2019-01-09 13:05 ` Vincenzo Frascino
2018-12-10 14:30 ` Vincenzo Frascino [this message]
2018-12-12 14:23 ` [RFC][PATCH 0/3] arm64 relaxed ABI Andrey Konovalov
2018-12-12 15:02 ` Catalin Marinas
2018-12-18 15:03 ` Andrey Konovalov
2018-12-18 17:59 ` Catalin Marinas
2018-12-19 12:52 ` Dave Martin
2019-02-11 17:28 ` Kevin Brodsky
2019-02-11 20:32 ` Evgenii Stepanov
2019-02-12 18:02 ` Catalin Marinas
2019-02-13 14:58 ` Dave Martin
2019-02-13 16:42 ` Kevin Brodsky
2019-02-13 17:43 ` Dave Martin
2019-02-13 21:41 ` Evgenii Stepanov
2019-02-14 11:22 ` Kevin Brodsky
2019-02-19 18:38 ` Szabolcs Nagy
2019-02-25 16:57 ` Catalin Marinas
2019-02-25 18:02 ` Szabolcs Nagy
2019-02-26 17:30 ` Kevin Brodsky
2018-12-12 17:01 ` [PATCH v9 0/8] arm64: untag user pointers passed to the kernel Dave Martin
2018-12-18 17:17 ` Andrey Konovalov
2019-02-11 11:35 ` Catalin Marinas
2019-02-11 17:02 ` Dave Martin
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