From 8fcd6c45f5a65621ec809b7866a3623e9a01d4ed Mon Sep 17 00:00:00 2001
From: Nicolas Pitre <nicolas.pitre@linaro.org>
Date: Fri, 28 Jul 2017 15:35:35 -0400
Subject: ARM: implement get_tls syscall

When there is no dedicated register to hold the tp value and no MMU
to provide a fixed address kuser helper entry point, all that is
left as fallback is a syscall.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Mickael GUENE <mickael.guene@st.com>
Tested-by: Vincent Abriou <vincent.abriou@st.com>
Tested-by: Andras Szemzo <szemzo.andras@gmail.com>
---
 arch/arm/kernel/traps.c | 3 +++
 1 file changed, 3 insertions(+)

(limited to 'arch/arm/kernel')

diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index 948c648fea00..43c0560f7b2d 100644
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -647,6 +647,9 @@ asmlinkage int arm_syscall(int no, struct pt_regs *regs)
 		set_tls(regs->ARM_r0);
 		return 0;
 
+	case NR(get_tls):
+		return current_thread_info()->tp_value[0];
+
 	default:
 		/* Calls 9f00xx..9f07ff are defined to return -ENOSYS
 		   if not implemented, rather than raising SIGILL.  This
-- 
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