arm64: tls: Avoid unconditional zeroing of tpidrro_el0 for native tasks

[android-x86/kernel.git] / arch / arm64 / kernel / process.c

diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 0e73949..0972ce5 100644 (file)
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -306,17 +306,17 @@ int copy_thread(unsigned long clone_flags, unsigned long stack_start,
 
 static void tls_thread_switch(struct task_struct *next)
 {
-       unsigned long tpidr, tpidrro;
+       unsigned long tpidr;
 
        tpidr = read_sysreg(tpidr_el0);
        *task_user_tls(current) = tpidr;
 
-       tpidr = *task_user_tls(next);
-       tpidrro = is_compat_thread(task_thread_info(next)) ?
-                 next->thread.tp_value : 0;
+       if (is_compat_thread(task_thread_info(next)))
+               write_sysreg(next->thread.tp_value, tpidrro_el0);
+       else if (!arm64_kernel_unmapped_at_el0())
+               write_sysreg(0, tpidrro_el0);
 
-       write_sysreg(tpidr, tpidr_el0);
-       write_sysreg(tpidrro, tpidrro_el0);
+       write_sysreg(*task_user_tls(next), tpidr_el0);
 }
 
 /* Restore the UAO state depending on next's addr_limit */