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Commit c12ae95c authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile 

* git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile:
  arch/tile: fix memchr() not to dereference memory for zero length
  arch/tile: make glibc's sysconf(_SC_NPROCESSORS_CONF) work correctly
  arch/tile: fix rwlock so would-be write lockers don't block new readers
parents 47143b09 3edabee2

arch/tile/kernel/setup.c

+1 −1
Original line number Diff line number Diff line
@@ -840,7 +840,7 @@ static int __init topology_init(void) 
	for_each_online_node(i)

		register_one_node(i);



	for_each_present_cpu(i)

	for (i = 0; i < smp_height * smp_width; ++i)

		register_cpu(&cpu_devices[i], i);



	return 0;

arch/tile/lib/memchr_32.c

+19 −16
Original line number Diff line number Diff line
@@ -18,12 +18,24 @@ 


void *memchr(const void *s, int c, size_t n)

{

	const uint32_t *last_word_ptr;

	const uint32_t *p;

	const char *last_byte_ptr;

	uintptr_t s_int;

	uint32_t goal, before_mask, v, bits;

	char *ret;



	if (__builtin_expect(n == 0, 0)) {

		/* Don't dereference any memory if the array is empty. */

		return NULL;

	}



	/* Get an aligned pointer. */

	const uintptr_t s_int = (uintptr_t) s;

	const uint32_t *p = (const uint32_t *)(s_int & -4);

	s_int = (uintptr_t) s;

	p = (const uint32_t *)(s_int & -4);



	/* Create four copies of the byte for which we are looking. */

	const uint32_t goal = 0x01010101 * (uint8_t) c;

	goal = 0x01010101 * (uint8_t) c;



	/* Read the first word, but munge it so that bytes before the array

	 * will not match goal.
@@ -31,23 +43,14 @@ void *memchr(const void *s, int c, size_t n) 
	 * Note that this shift count expression works because we know

	 * shift counts are taken mod 32.

	 */

	const uint32_t before_mask = (1 << (s_int << 3)) - 1;

	uint32_t v = (*p | before_mask) ^ (goal & before_mask);

	before_mask = (1 << (s_int << 3)) - 1;

	v = (*p | before_mask) ^ (goal & before_mask);



	/* Compute the address of the last byte. */

	const char *const last_byte_ptr = (const char *)s + n - 1;

	last_byte_ptr = (const char *)s + n - 1;



	/* Compute the address of the word containing the last byte. */

	const uint32_t *const last_word_ptr =

	    (const uint32_t *)((uintptr_t) last_byte_ptr & -4);



	uint32_t bits;

	char *ret;



	if (__builtin_expect(n == 0, 0)) {

		/* Don't dereference any memory if the array is empty. */

		return NULL;

	}

	last_word_ptr = (const uint32_t *)((uintptr_t) last_byte_ptr & -4);



	while ((bits = __insn_seqb(v, goal)) == 0) {

		if (__builtin_expect(p == last_word_ptr, 0)) {

arch/tile/lib/spinlock_32.c

+18 −11
Original line number Diff line number Diff line
@@ -167,23 +167,30 @@ void arch_write_lock_slow(arch_rwlock_t *rwlock, u32 val) 
	 * when we compare them.

	 */

	u32 my_ticket_;

	u32 iterations = 0;



	/* Take out the next ticket; this will also stop would-be readers. */

	if (val & 1)

		val = get_rwlock(rwlock);

	rwlock->lock = __insn_addb(val, 1 << WR_NEXT_SHIFT);

	/*

	 * Wait until there are no readers, then bump up the next

	 * field and capture the ticket value.

	 */

	for (;;) {

		if (!(val & 1)) {

			if ((val >> RD_COUNT_SHIFT) == 0)

				break;

			rwlock->lock = val;

		}

		delay_backoff(iterations++);

		val = __insn_tns((int *)&rwlock->lock);

	}



	/* Extract my ticket value from the original word. */

	/* Take out the next ticket and extract my ticket value. */

	rwlock->lock = __insn_addb(val, 1 << WR_NEXT_SHIFT);

	my_ticket_ = val >> WR_NEXT_SHIFT;



	/*

	 * Wait until the "current" field matches our ticket, and

	 * there are no remaining readers.

	 */

	/* Wait until the "current" field matches our ticket. */

	for (;;) {

		u32 curr_ = val >> WR_CURR_SHIFT;

		u32 readers = val >> RD_COUNT_SHIFT;

		u32 delta = ((my_ticket_ - curr_) & WR_MASK) + !!readers;

		u32 delta = ((my_ticket_ - curr_) & WR_MASK);

		if (likely(delta == 0))

			break;