[PATCH 5.4 62/78] xtensa: Implement copy_thread_tls

Greg Kroah-Hartman
2020-01-14T10:06:56Z

From: Amanieu d'Antras <amanieu@gmail.com>

commit c346b94f8c5d1b7d637522c908209de93305a8eb upstream.

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
Link: https://lore.kernel.org/r/20200102172413.654385-7-amanieu@gmail.com
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/xtensa/Kconfig | 1 +
arch/xtensa/kernel/process.c | 8 ++++----
2 files changed, 5 insertions(+), 4 deletions(-)

--- a/arch/xtensa/Kconfig
+++ b/arch/xtensa/Kconfig
@@ -22,6 +22,7 @@ config XTENSA
select HAVE_ARCH_JUMP_LABEL
select HAVE_ARCH_KASAN if MMU
select HAVE_ARCH_TRACEHOOK
+ select HAVE_COPY_THREAD_TLS
select HAVE_DEBUG_KMEMLEAK
select HAVE_DMA_CONTIGUOUS
select HAVE_EXIT_THREAD
--- a/arch/xtensa/kernel/process.c
+++ b/arch/xtensa/kernel/process.c
@@ -202,8 +202,9 @@ int arch_dup_task_struct(struct task_str
* 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);

@@ -264,9 +265,8 @@ int copy_thread(unsigned long clone_flag
&regs->areg[XCHAL_NUM_AREGS - len/4], len);
}

- /* 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);