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Commit 3bec6ded authored by Lennert Buytenhek's avatar Lennert Buytenhek Committed by Russell King
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[ARM] 3664/1: crunch: add signal frame save/restore 



Patch from Lennert Buytenhek

This patch makes the kernel save Crunch state in userland signal frames,
so that any userland signal handler can safely use the Crunch coprocessor
without corrupting the Crunch state of the code it preempted.

Signed-off-by: default avatarLennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 562ca1e3

arch/arm/kernel/signal.c

+39 −0
Original line number Original line Diff line number Diff line
@@ -132,6 +132,37 @@ sys_sigaction(int sig, const struct old_sigaction __user *act, 
	return ret;

	return ret;

}

}





#ifdef CONFIG_CRUNCH

static int preserve_crunch_context(struct crunch_sigframe *frame)

{

	char kbuf[sizeof(*frame) + 8];

	struct crunch_sigframe *kframe;



	/* the crunch context must be 64 bit aligned */

	kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7);

	kframe->magic = CRUNCH_MAGIC;

	kframe->size = CRUNCH_STORAGE_SIZE;

	crunch_task_copy(current_thread_info(), &kframe->storage);

	return __copy_to_user(frame, kframe, sizeof(*frame));

}



static int restore_crunch_context(struct crunch_sigframe *frame)

{

	char kbuf[sizeof(*frame) + 8];

	struct crunch_sigframe *kframe;



	/* the crunch context must be 64 bit aligned */

	kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7);

	if (__copy_from_user(kframe, frame, sizeof(*frame)))

		return -1;

	if (kframe->magic != CRUNCH_MAGIC ||

	    kframe->size != CRUNCH_STORAGE_SIZE)

		return -1;

	crunch_task_restore(current_thread_info(), &kframe->storage);

	return 0;

}

#endif



#ifdef CONFIG_IWMMXT

#ifdef CONFIG_IWMMXT





static int preserve_iwmmxt_context(struct iwmmxt_sigframe *frame)

static int preserve_iwmmxt_context(struct iwmmxt_sigframe *frame)
@@ -214,6 +245,10 @@ static int restore_sigframe(struct pt_regs *regs, struct sigframe __user *sf) 
	err |= !valid_user_regs(regs);

	err |= !valid_user_regs(regs);





	aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;

	aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;

#ifdef CONFIG_CRUNCH

	if (err == 0)

		err |= restore_crunch_context(&aux->crunch);

#endif

#ifdef CONFIG_IWMMXT

#ifdef CONFIG_IWMMXT

	if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))

	if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))

		err |= restore_iwmmxt_context(&aux->iwmmxt);

		err |= restore_iwmmxt_context(&aux->iwmmxt);
@@ -333,6 +368,10 @@ setup_sigframe(struct sigframe __user *sf, struct pt_regs *regs, sigset_t *set) 
	err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set));

	err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set));





	aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;

	aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;

#ifdef CONFIG_CRUNCH

	if (err == 0)

		err |= preserve_crunch_context(&aux->crunch);

#endif

#ifdef CONFIG_IWMMXT

#ifdef CONFIG_IWMMXT

	if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))

	if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))

		err |= preserve_iwmmxt_context(&aux->iwmmxt);

		err |= preserve_iwmmxt_context(&aux->iwmmxt);

include/asm-arm/ucontext.h

+14 −0
Original line number Original line Diff line number Diff line
@@ -35,6 +35,17 @@ struct ucontext { 
 * bytes, to prevent unpredictable padding in the signal frame.

 * bytes, to prevent unpredictable padding in the signal frame.

 */

 */





#ifdef CONFIG_CRUNCH

#define CRUNCH_MAGIC		0x5065cf03

#define CRUNCH_STORAGE_SIZE	(CRUNCH_SIZE + 8)



struct crunch_sigframe {

	unsigned long	magic;

	unsigned long	size;

	struct crunch_state	storage;

} __attribute__((__aligned__(8)));

#endif



#ifdef CONFIG_IWMMXT

#ifdef CONFIG_IWMMXT

/* iwmmxt_area is 0x98 bytes long, preceeded by 8 bytes of signature */

/* iwmmxt_area is 0x98 bytes long, preceeded by 8 bytes of signature */

#define IWMMXT_MAGIC		0x12ef842a

#define IWMMXT_MAGIC		0x12ef842a
@@ -74,6 +85,9 @@ struct vfp_sigframe 
 * one of these.

 * one of these.

 */

 */

struct aux_sigframe {

struct aux_sigframe {

#ifdef CONFIG_CRUNCH

	struct crunch_sigframe	crunch;

#endif

#ifdef CONFIG_IWMMXT

#ifdef CONFIG_IWMMXT

	struct iwmmxt_sigframe	iwmmxt;

	struct iwmmxt_sigframe	iwmmxt;

#endif

#endif