Unverified Commit 457677c7 authored by Amanieu d'Antras's avatar Amanieu d'Antras Committed by Christian Brauner
Browse files

um: Implement copy_thread_tls 



This is required for clone3 which passes the TLS value through a
struct rather than a register.

Signed-off-by: default avatarAmanieu d'Antras <amanieu@gmail.com>
Cc: linux-um@lists.infradead.org
Cc: <stable@vger.kernel.org> # 5.3.x
Link: https://lore.kernel.org/r/20200104123928.1048822-1-amanieu@gmail.com


Signed-off-by: default avatarChristian Brauner <christian.brauner@ubuntu.com>
parent dd499f7a

arch/um/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ config UML 
	select HAVE_FUTEX_CMPXCHG if FUTEX

	select HAVE_DEBUG_KMEMLEAK

	select HAVE_DEBUG_BUGVERBOSE

	select HAVE_COPY_THREAD_TLS

	select GENERIC_IRQ_SHOW

	select GENERIC_CPU_DEVICES

	select GENERIC_CLOCKEVENTS

arch/um/include/asm/ptrace-generic.h

+1 −1
Original line number Diff line number Diff line
@@ -36,7 +36,7 @@ extern long subarch_ptrace(struct task_struct *child, long request, 
extern unsigned long getreg(struct task_struct *child, int regno);

extern int putreg(struct task_struct *child, int regno, unsigned long value);



extern int arch_copy_tls(struct task_struct *new);

extern int arch_set_tls(struct task_struct *new, unsigned long tls);

extern void clear_flushed_tls(struct task_struct *task);

extern int syscall_trace_enter(struct pt_regs *regs);

extern void syscall_trace_leave(struct pt_regs *regs);

arch/um/kernel/process.c

+3 −3
Original line number Diff line number Diff line
@@ -153,8 +153,8 @@ void fork_handler(void) 
	userspace(&current->thread.regs.regs, current_thread_info()->aux_fp_regs);

}



int copy_thread(unsigned long clone_flags, unsigned long sp,

		unsigned long arg, struct task_struct * p)

int copy_thread_tls(unsigned long clone_flags, unsigned long sp,

		unsigned long arg, struct task_struct * p, unsigned long tls)

{

	void (*handler)(void);

	int kthread = current->flags & PF_KTHREAD;
@@ -188,7 +188,7 @@ int copy_thread(unsigned long clone_flags, unsigned long sp, 
		 * Set a new TLS for the child thread?

		 */

		if (clone_flags & CLONE_SETTLS)

			ret = arch_copy_tls(p);

			ret = arch_set_tls(p, tls);

	}



	return ret;

arch/x86/um/tls_32.c

+2 −4
Original line number Diff line number Diff line
@@ -215,14 +215,12 @@ static int set_tls_entry(struct task_struct* task, struct user_desc *info, 
	return 0;

}



int arch_copy_tls(struct task_struct *new)

int arch_set_tls(struct task_struct *new, unsigned long tls)

{

	struct user_desc info;

	int idx, ret = -EFAULT;



	if (copy_from_user(&info,

			   (void __user *) UPT_SI(&new->thread.regs.regs),

			   sizeof(info)))

	if (copy_from_user(&info, (void __user *) tls, sizeof(info)))

		goto out;



	ret = -EINVAL;

arch/x86/um/tls_64.c

+3 −4
Original line number Diff line number Diff line
@@ -6,14 +6,13 @@ void clear_flushed_tls(struct task_struct *task) 
{

}



int arch_copy_tls(struct task_struct *t)

int arch_set_tls(struct task_struct *t, unsigned long tls)

{

	/*

	 * If CLONE_SETTLS is set, we need to save the thread id

	 * (which is argument 5, child_tid, of clone) so it can be set

	 * during context switches.

	 * so it can be set during context switches.

	 */

	t->thread.arch.fs = t->thread.regs.regs.gp[R8 / sizeof(long)];

	t->thread.arch.fs = tls;



	return 0;

}

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