arm64: Implement copy_thread_tls

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
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20200102172413.654385-3-amanieu@gmail.com
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index b1b4476..e688dfa 100644 (file)
--- 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 71f788c..d54586d 100644 (file)
--- 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;