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From:   Amanieu d'Antras <amanieu@gmail.com>
To:     linux-kernel@vger.kernel.org
Cc:     Christian Brauner <christian@brauner.io>, stable@vger.kernel.org,
        Amanieu d'Antras <amanieu@gmail.com>,
        linux-arm-kernel@lists.infradead.org
Subject: [PATCH 2/7] arm64: Implement copy_thread_tls
Date:   Thu,  2 Jan 2020 18:24:08 +0100
Message-Id: <20200102172413.654385-3-amanieu@gmail.com>
In-Reply-To: <20200102172413.654385-1-amanieu@gmail.com>
References: <20200102172413.654385-1-amanieu@gmail.com>
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This is required for clone3 which passes the TLS value through a
struct rather than a register.

Signed-off-by: Amanieu d'Antras <amanieu@gmail.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: <stable@vger.kernel.org> # 5.3.x
---
 arch/arm64/Kconfig          |  1 +
 arch/arm64/kernel/process.c | 10 +++++-----
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index b1b4476ddb83..e688dfad0b72 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -138,6 +138,7 @@ config ARM64
 	select HAVE_CMPXCHG_DOUBLE
 	select HAVE_CMPXCHG_LOCAL
 	select HAVE_CONTEXT_TRACKING
+	select HAVE_COPY_THREAD_TLS
 	select HAVE_DEBUG_BUGVERBOSE
 	select HAVE_DEBUG_KMEMLEAK
 	select HAVE_DMA_CONTIGUOUS
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 71f788cd2b18..d54586d5b031 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -360,8 +360,8 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
 
 asmlinkage void ret_from_fork(void) asm("ret_from_fork");
 
-int copy_thread(unsigned long clone_flags, unsigned long stack_start,
-		unsigned long stk_sz, struct task_struct *p)
+int copy_thread_tls(unsigned long clone_flags, unsigned long stack_start,
+		unsigned long stk_sz, struct task_struct *p, unsigned long tls)
 {
 	struct pt_regs *childregs = task_pt_regs(p);
 
@@ -394,11 +394,11 @@ int copy_thread(unsigned long clone_flags, unsigned long stack_start,
 		}
 
 		/*
-		 * If a TLS pointer was passed to clone (4th argument), use it
-		 * for the new thread.
+		 * If a TLS pointer was passed to clone, use it for the new
+		 * thread.
 		 */
 		if (clone_flags & CLONE_SETTLS)
-			p->thread.uw.tp_value = childregs->regs[3];
+			p->thread.uw.tp_value = tls;
 	} else {
 		memset(childregs, 0, sizeof(struct pt_regs));
 		childregs->pstate = PSR_MODE_EL1h;
-- 
2.24.1