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Commit c1bd55f9 authored by Josh Triplett's avatar Josh Triplett Committed by Linus Torvalds
Browse files

x86: opt into HAVE_COPY_THREAD_TLS, for both 32-bit and 64-bit 



For 32-bit userspace on a 64-bit kernel, this requires modifying
stub32_clone to actually swap the appropriate arguments to match
CONFIG_CLONE_BACKWARDS, rather than just leaving the C argument for tls
broken.

Patch co-authored by Josh Triplett and Thiago Macieira.

Signed-off-by: default avatarJosh Triplett <josh@joshtriplett.org>
Acked-by: default avatarAndy Lutomirski <luto@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thiago Macieira <thiago.macieira@intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 20263029

arch/x86/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -88,6 +88,7 @@ config X86 
	select HAVE_CMPXCHG_DOUBLE

	select HAVE_CMPXCHG_LOCAL

	select HAVE_CONTEXT_TRACKING		if X86_64

	select HAVE_COPY_THREAD_TLS

	select HAVE_C_RECORDMCOUNT

	select HAVE_DEBUG_KMEMLEAK

	select HAVE_DEBUG_STACKOVERFLOW

arch/x86/kernel/process_32.c

+3 −3
Original line number Diff line number Diff line
@@ -128,8 +128,8 @@ void release_thread(struct task_struct *dead_task) 
	release_vm86_irqs(dead_task);

}



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)

{

	struct pt_regs *childregs = task_pt_regs(p);

	struct task_struct *tsk;
@@ -184,7 +184,7 @@ int copy_thread(unsigned long clone_flags, unsigned long sp, 
	 */

	if (clone_flags & CLONE_SETTLS)

		err = do_set_thread_area(p, -1,

			(struct user_desc __user *)childregs->si, 0);

			(struct user_desc __user *)tls, 0);



	if (err && p->thread.io_bitmap_ptr) {

		kfree(p->thread.io_bitmap_ptr);

arch/x86/kernel/process_64.c

+4 −4
Original line number Diff line number Diff line
@@ -150,8 +150,8 @@ static inline u32 read_32bit_tls(struct task_struct *t, int tls) 
	return get_desc_base(&t->thread.tls_array[tls]);

}



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)

{

	int err;

	struct pt_regs *childregs;
@@ -207,10 +207,10 @@ int copy_thread(unsigned long clone_flags, unsigned long sp, 
#ifdef CONFIG_IA32_EMULATION

		if (is_ia32_task())

			err = do_set_thread_area(p, -1,

				(struct user_desc __user *)childregs->si, 0);

				(struct user_desc __user *)tls, 0);

		else

#endif

			err = do_arch_prctl(p, ARCH_SET_FS, childregs->r8);

			err = do_arch_prctl(p, ARCH_SET_FS, tls);

		if (err)

			goto out;

	}