Le 27/08/2019 à 05:30, Nicholas Piggin a écrit :
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 <npig...@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.
if (!is_32bit_task())
- childregs->gpr[13] = childregs->gpr[6];
+ childregs->gpr[13] = tls;
else
#endif
- childregs->gpr[2] = childregs->gpr[6];
+ childregs->gpr[2] = tls;
}
f = ret_from_fork;
Christophe
