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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-xtensa@linux-xtensa.org
Subject: [PATCH 6/7] xtensa: Implement copy_thread_tls
Date:   Thu,  2 Jan 2020 18:24:12 +0100
Message-Id: <20200102172413.654385-7-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-xtensa@linux-xtensa.org
Cc: <stable@vger.kernel.org> # 5.3.x
---
 arch/xtensa/Kconfig          | 1 +
 arch/xtensa/kernel/process.c | 8 ++++----
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig
index 4a3fa295d8fe..296c5324dace 100644
--- a/arch/xtensa/Kconfig
+++ b/arch/xtensa/Kconfig
@@ -24,6 +24,7 @@ config XTENSA
 	select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL
 	select HAVE_ARCH_KASAN if MMU && !XIP_KERNEL
 	select HAVE_ARCH_TRACEHOOK
+	select HAVE_COPY_THREAD_TLS
 	select HAVE_DEBUG_KMEMLEAK
 	select HAVE_DMA_CONTIGUOUS
 	select HAVE_EXIT_THREAD
diff --git a/arch/xtensa/kernel/process.c b/arch/xtensa/kernel/process.c
index 9e1c49134c07..3edecc41ef8c 100644
--- a/arch/xtensa/kernel/process.c
+++ b/arch/xtensa/kernel/process.c
@@ -202,8 +202,9 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
  * involved.  Much simpler to just not copy those live frames across.
  */
 
-int copy_thread(unsigned long clone_flags, unsigned long usp_thread_fn,
-		unsigned long thread_fn_arg, struct task_struct *p)
+int copy_thread_tls(unsigned long clone_flags, unsigned long usp_thread_fn,
+		unsigned long thread_fn_arg, struct task_struct *p,
+		unsigned long tls)
 {
 	struct pt_regs *childregs = task_pt_regs(p);
 
@@ -266,9 +267,8 @@ int copy_thread(unsigned long clone_flags, unsigned long usp_thread_fn,
 
 		childregs->syscall = regs->syscall;
 
-		/* The thread pointer is passed in the '4th argument' (= a5) */
 		if (clone_flags & CLONE_SETTLS)
-			childregs->threadptr = childregs->areg[5];
+			childregs->threadptr = tls;
 	} else {
 		p->thread.ra = MAKE_RA_FOR_CALL(
 				(unsigned long)ret_from_kernel_thread, 1);
-- 
2.24.1