Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 07b047fc authored by akpm@osdl.org's avatar akpm@osdl.org Committed by Linus Torvalds
Browse files

[PATCH] i386: fix task_pt_regs() 



)

From: Al Viro <viro@ftp.linux.org.uk>

task_pt_regs() needs the same offset-by-8 to match copy_thread()

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 06b425d8

arch/i386/kernel/process.c

+2 −18
Original line number Original line Diff line number Diff line
@@ -424,18 +424,7 @@ int copy_thread(int nr, unsigned long clone_flags, unsigned long esp, 
	struct task_struct *tsk;

	struct task_struct *tsk;

	int err;

	int err;





	childregs = ((struct pt_regs *) (THREAD_SIZE + (unsigned long) p->thread_info)) - 1;

	childregs = task_pt_regs(p);

	/*

	 * The below -8 is to reserve 8 bytes on top of the ring0 stack.

	 * This is necessary to guarantee that the entire "struct pt_regs"

	 * is accessable even if the CPU haven't stored the SS/ESP registers

	 * on the stack (interrupt gate does not save these registers

	 * when switching to the same priv ring).

	 * Therefore beware: accessing the xss/esp fields of the

	 * "struct pt_regs" is possible, but they may contain the

	 * completely wrong values.

	 */

	childregs = (struct pt_regs *) ((unsigned long) childregs - 8);

	*childregs = *regs;

	*childregs = *regs;

	childregs->eax = 0;

	childregs->eax = 0;

	childregs->esp = esp;

	childregs->esp = esp;
@@ -540,12 +529,7 @@ EXPORT_SYMBOL(dump_thread); 
 */

 */

int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs)

int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs)

{

{

	struct pt_regs ptregs;

	struct pt_regs ptregs = *task_pt_regs(tsk);

	

	ptregs = *(struct pt_regs *)

		((unsigned long)tsk->thread_info +

		/* see comments in copy_thread() about -8 */

		THREAD_SIZE - sizeof(ptregs) - 8);

	ptregs.xcs &= 0xffff;

	ptregs.xcs &= 0xffff;

	ptregs.xds &= 0xffff;

	ptregs.xds &= 0xffff;

	ptregs.xes &= 0xffff;

	ptregs.xes &= 0xffff;

arch/i386/kernel/smpboot.c

+1 −2
Original line number Original line Diff line number Diff line
@@ -875,8 +875,7 @@ static inline struct task_struct * alloc_idle_task(int cpu) 
		/* initialize thread_struct.  we really want to avoid destroy

		/* initialize thread_struct.  we really want to avoid destroy

		 * idle tread

		 * idle tread

		 */

		 */

		idle->thread.esp = (unsigned long)(((struct pt_regs *)

		idle->thread.esp = (unsigned long)task_pt_regs(idle);

			(THREAD_SIZE + (unsigned long) idle->thread_info)) - 1);

		init_idle(idle, cpu);

		init_idle(idle, cpu);

		return idle;

		return idle;

	}

	}

include/asm-i386/processor.h

+11 −1
Original line number Original line Diff line number Diff line
@@ -561,10 +561,20 @@ unsigned long get_wchan(struct task_struct *p); 
       (unsigned long)(&__ptr[THREAD_SIZE_LONGS]);                     \

       (unsigned long)(&__ptr[THREAD_SIZE_LONGS]);                     \

})

})





/*

 * The below -8 is to reserve 8 bytes on top of the ring0 stack.

 * This is necessary to guarantee that the entire "struct pt_regs"

 * is accessable even if the CPU haven't stored the SS/ESP registers

 * on the stack (interrupt gate does not save these registers

 * when switching to the same priv ring).

 * Therefore beware: accessing the xss/esp fields of the

 * "struct pt_regs" is possible, but they may contain the

 * completely wrong values.

 */

#define task_pt_regs(task)                                             \

#define task_pt_regs(task)                                             \

({                                                                     \

({                                                                     \

       struct pt_regs *__regs__;                                       \

       struct pt_regs *__regs__;                                       \

       __regs__ = (struct pt_regs *)KSTK_TOP((task)->thread_info);     \

       __regs__ = (struct pt_regs *)(KSTK_TOP((task)->thread_info)-8); \

       __regs__ - 1;                                                   \

       __regs__ - 1;                                                   \

})

})