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powerpc: convert to copy_thread_tls

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Commit 3033f14ab7 ("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>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190827033010.28090-2-npiggin@gmail.com
This commit is contained in:
Nicholas Piggin 2019-08-27 13:30:06 +10:00 committed by Michael Ellerman
parent c7bf1252d5
commit facd04a904
2 changed files with 6 additions and 4 deletions
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1
arch/powerpc/Kconfig
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@ -184,6 +184,7 @@ 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

9
arch/powerpc/kernel/process.c
View File

@ -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
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;