Le 27/08/2019 à 12:13, Nicholas Piggin a écrit :

Christophe Leroy's on August 27, 2019 4:07 pm:

quoted

Le 27/08/2019 à 05:30, Nicholas Piggin a écrit :

quoted

Commit 3033f14ab78c3 ("clone: support passing tls argument via C rather
than pt_regs magic") introduced the HAVE_COPY_THREAD_TLS option. Use it
to avoid a subtle assumption about the argument ordering of clone type
syscalls.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
   arch/powerpc/Kconfig          | 1 +
   arch/powerpc/kernel/process.c | 9 +++++----
   2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index d8dcd8820369..7477a3263225 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig

@@ -182,6 +182,7 @@ config PPC
   	select HAVE_STACKPROTECTOR		if PPC64 && $(cc-option,-mstack-protector-guard=tls -mstack-protector-guard-reg=r13)
   	select HAVE_STACKPROTECTOR		if PPC32 && $(cc-option,-mstack-protector-guard=tls -mstack-protector-guard-reg=r2)
   	select HAVE_CONTEXT_TRACKING		if PPC64
+	select HAVE_COPY_THREAD_TLS
   	select HAVE_DEBUG_KMEMLEAK
   	select HAVE_DEBUG_STACKOVERFLOW
   	select HAVE_DYNAMIC_FTRACE

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 8fc4de0d22b4..24621e7e5033 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c

@@ -1600,8 +1600,9 @@ static void setup_ksp_vsid(struct task_struct *p, unsigned long sp)
   /*
    * Copy architecture-specific thread state
    */
-int copy_thread(unsigned long clone_flags, unsigned long usp,
-		unsigned long kthread_arg, struct task_struct *p)
+int copy_thread_tls(unsigned long clone_flags, unsigned long usp,
+		unsigned long kthread_arg, struct task_struct *p,
+		unsigned long tls)
   {
   	struct pt_regs *childregs, *kregs;
   	extern void ret_from_fork(void);

@@ -1642,10 +1643,10 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
   		if (clone_flags & CLONE_SETTLS) {
   #ifdef CONFIG_PPC64

is_32bit_task() exists and always returns 1 on PPC32 so this gross ifdef
in the middle of an if/else is pointless, it should be dropped.

I could do that as another patch in the series.

Yes, would be good, because if I do an independant patch for that it 
will conflict with your series.

Thanks
Christophe