riscv: Implement copy_thread_tls

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>

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 8eebbc8..ade9699 100644 (file)
--- 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

diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c
index 85e3c39..330b347 100644 (file)
--- a/arch/riscv/kernel/process.c
+++ b/arch/riscv/kernel/process.c
@@ -99,8 +99,8 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
        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_flags, unsigned long usp,
                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;
        }