[PATCH 5.4 59/78] arm: Implement copy_thread_tls

Greg Kroah-Hartman
2020-01-14T10:05:38Z

From: Amanieu d'Antras <amanieu@gmail.com>

commit 167ee0b82429cb5df272808c7a21370b7c961ab2 upstream.

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
Link: https://lore.kernel.org/r/20200102172413.654385-4-amanieu@gmail.com
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/arm/Kconfig | 1 +
arch/arm/kernel/process.c | 6 +++---
2 files changed, 4 insertions(+), 3 deletions(-)

--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -73,6 +73,7 @@ config ARM
select HAVE_ARM_SMCCC if CPU_V7
select HAVE_EBPF_JIT if !CPU_ENDIAN_BE32
select HAVE_CONTEXT_TRACKING
+ select HAVE_COPY_THREAD_TLS
select HAVE_C_RECORDMCOUNT
select HAVE_DEBUG_KMEMLEAK
select HAVE_DMA_CONTIGUOUS if MMU
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -224,8 +224,8 @@ void release_thread(struct task_struct *
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)
+copy_thread_tls(unsigned long clone_flags, unsigned long stack_start,
+ unsigned long stk_sz, struct task_struct *p, unsigned long tls)
{
struct thread_info *thread = task_thread_info(p);
struct pt_regs *childregs = task_pt_regs(p);
@@ -259,7 +259,7 @@ copy_thread(unsigned long clone_flags, u
clear_ptrace_hw_breakpoint(p);

if (clone_flags & CLONE_SETTLS)
- thread->tp_value[0] = childregs->ARM_r3;
+ thread->tp_value[0] = tls;
thread->tp_value[1] = get_tpuser();

thread_notify(THREAD_NOTIFY_COPY, thread);