[PATCH 5.4 61/78] riscv: Implement copy_thread_tls

Greg Kroah-Hartman
2020-01-14T10:05:44Z

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

commit 20bda4ed62f507ed72e30e817b43c65fdba60be7 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-riscv@lists.infradead.org
Cc: <stable@vger.kernel.org> # 5.3.x
Link: https://lore.kernel.org/r/20200102172413.654385-6-amanieu@gmail.com
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/riscv/Kconfig | 1 +
arch/riscv/kernel/process.c | 6 +++---
2 files changed, 4 insertions(+), 3 deletions(-)

--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -61,6 +61,7 @@ config RISCV
select SPARSEMEM_STATIC if 32BIT
select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU
select HAVE_ARCH_MMAP_RND_BITS
+ select HAVE_COPY_THREAD_TLS

config ARCH_MMAP_RND_BITS_MIN
default 18 if 64BIT
--- a/arch/riscv/kernel/process.c
+++ b/arch/riscv/kernel/process.c
@@ -99,8 +99,8 @@ int arch_dup_task_struct(struct task_str
return 0;
}

-int copy_thread(unsigned long clone_flags, unsigned long usp,
- unsigned long arg, struct task_struct *p)
+int copy_thread_tls(unsigned long clone_flags, unsigned long usp,
+ unsigned long arg, struct task_struct *p, unsigned long tls)
{
struct pt_regs *childregs = task_pt_regs(p);

@@ -120,7 +120,7 @@ int copy_thread(unsigned long clone_flag
if (usp) /* User fork */
childregs->sp = usp;
if (clone_flags & CLONE_SETTLS)
- childregs->tp = childregs->a5;
+ childregs->tp = tls;
childregs->a0 = 0; /* Return value of fork() */
p->thread.ra = (unsigned long)ret_from_fork;
}