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authorCatalin Marinas <catalin.marinas@arm.com>2019-07-23 19:58:39 +0200
committerWill Deacon <will@kernel.org>2019-08-06 18:08:45 +0100
commit63f0c60379650d82250f22e4cf4137ef3dc4f43d (patch)
treeaf76cdc5d0eeca023d86c43664d073af25d63546 /arch/arm64/include/asm/thread_info.h
parent2b835e24b5c6f9c633ff51973581ee7ca7b3e8ec (diff)
downloadlinux-63f0c60379650d82250f22e4cf4137ef3dc4f43d.tar.bz2
arm64: Introduce prctl() options to control the tagged user addresses ABI
It is not desirable to relax the ABI to allow tagged user addresses into the kernel indiscriminately. This patch introduces a prctl() interface for enabling or disabling the tagged ABI with a global sysctl control for preventing applications from enabling the relaxed ABI (meant for testing user-space prctl() return error checking without reconfiguring the kernel). The ABI properties are inherited by threads of the same application and fork()'ed children but cleared on execve(). A Kconfig option allows the overall disabling of the relaxed ABI. The PR_SET_TAGGED_ADDR_CTRL will be expanded in the future to handle MTE-specific settings like imprecise vs precise exceptions. Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'arch/arm64/include/asm/thread_info.h')
-rw-r--r--arch/arm64/include/asm/thread_info.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h
index 180b34ec5965..012238d8e58d 100644
--- a/arch/arm64/include/asm/thread_info.h
+++ b/arch/arm64/include/asm/thread_info.h
@@ -90,6 +90,7 @@ void arch_release_task_struct(struct task_struct *tsk);
#define TIF_SVE 23 /* Scalable Vector Extension in use */
#define TIF_SVE_VL_INHERIT 24 /* Inherit sve_vl_onexec across exec */
#define TIF_SSBD 25 /* Wants SSB mitigation */
+#define TIF_TAGGED_ADDR 26 /* Allow tagged user addresses */
#define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)