Merge tag 'clk-fixes-for-linus' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/clk/linux

Pull clk fixes from Stephen Boyd: "Two fixes for the NKMP clks on Allwinner SoCs, a locking fix for clkdev where we forgot to hold a lock while iterating a list that can change, and finally a build fix that adds some stubs for clk APIs that are used by devfreq drivers on platforms without the clk APIs" * tag 'clk-fixes-for-linus' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/clk/linux: clk: Add missing stubs for a few functions clkdev: Hold clocks_mutex while iterating clocks list clk: sunxi-ng: nkmp: Explain why zero width check is needed clk: sunxi-ng: nkmp: Avoid GENMASK(-1, 0)

Linus Torvalds committed 7 years ago

Commit 8f762162 parents 46572f7 b88c9f43 files · +40 −5Browse files

Unified · Split

3 files

drivers/clk/clkdev.c +5 −0
drivers/clk/sunxi-ng/ccu_nkmp.c +19 −5
include/linux/clk.h +16 −0

drivers/clk/clkdev.c+5−0

 	if (con_id)
 		best_possible += 1;
+	lockdep_assert_held(&clocks_mutex);
 	list_for_each_entry(p, &clocks, node) {
 		match = 0;
 		if (p->dev_id) {
 	struct clk_lookup *cl;
 	int rval;
+	mutex_lock(&clocks_mutex);
 	cl = clk_find(dev_id, con_id);
+	mutex_unlock(&clocks_mutex);
 	WARN_ON(!cl);
 	rval = devres_release(dev, devm_clkdev_release,
 			      devm_clk_match_clkdev, cl);

drivers/clk/sunxi-ng/ccu_nkmp.c+19−5

 			   unsigned long parent_rate)
 {
 	struct ccu_nkmp *nkmp = hw_to_ccu_nkmp(hw);
-	u32 n_mask, k_mask, m_mask, p_mask;
+	u32 n_mask = 0, k_mask = 0, m_mask = 0, p_mask = 0;
 	struct _ccu_nkmp _nkmp;
 	unsigned long flags;
 	u32 reg;
 	ccu_nkmp_find_best(parent_rate, rate, &_nkmp);
-	n_mask = GENMASK(nkmp->n.width + nkmp->n.shift - 1, nkmp->n.shift);
+	/*
-	k_mask = GENMASK(nkmp->k.width + nkmp->k.shift - 1, nkmp->k.shift);
+	 * If width is 0, GENMASK() macro may not generate expected mask (0)
-	m_mask = GENMASK(nkmp->m.width + nkmp->m.shift - 1, nkmp->m.shift);
+	 * as it falls under undefined behaviour by C standard due to shifts
-	p_mask = GENMASK(nkmp->p.width + nkmp->p.shift - 1, nkmp->p.shift);
+	 * which are equal or greater than width of left operand. This can
+	 * be easily avoided by explicitly checking if width is 0.
+	 */
+	if (nkmp->n.width)
+		n_mask = GENMASK(nkmp->n.width + nkmp->n.shift - 1,
+				 nkmp->n.shift);
+	if (nkmp->k.width)
+		k_mask = GENMASK(nkmp->k.width + nkmp->k.shift - 1,
+				 nkmp->k.shift);
+	if (nkmp->m.width)
+		m_mask = GENMASK(nkmp->m.width + nkmp->m.shift - 1,
+				 nkmp->m.shift);
+	if (nkmp->p.width)
+		p_mask = GENMASK(nkmp->p.width + nkmp->p.shift - 1,
+				 nkmp->p.shift);
 	spin_lock_irqsave(nkmp->common.lock, flags);

include/linux/clk.h+16−0

@@ -811,6 +811,22 @@ static inline bool clk_has_parent(struct clk clk, struct clk parent) · 810 unmodified lines
811	return true;	811	return true;
812	}	812	}
813		813
		814	static inline int clk_set_rate_range(struct clk *clk, unsigned long min,
		815	unsigned long max)
		816	{
		817	return 0;
		818	}
		819
		820	static inline int clk_set_min_rate(struct clk *clk, unsigned long rate)
		821	{
		822	return 0;
		823	}
		824
		825	static inline int clk_set_max_rate(struct clk *clk, unsigned long rate)
		826	{
		827	return 0;
		828	}
		829
814	static inline int clk_set_parent(struct clk clk, struct clk parent)	830	static inline int clk_set_parent(struct clk clk, struct clk parent)
815	{	831	{
816	return 0;	832	return 0;