Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6

torvalds · torvalds · commit d9cee5d4f66e · 2015-05-05T09:03:52.000-07:00
Pull crypto fixes from Herbert Xu:
 "This fixes a build problem with bcm63xx and yet another fix to the
  memzero_explicit function to ensure that the memset is not elided"

* git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
  hwrng: bcm63xx - Fix driver compilation
  lib: make memzero_explicit more robust against dead store elimination
diff --git a/drivers/char/hw_random/bcm63xx-rng.c b/drivers/char/hw_random/bcm63xx-rng.c
@@ -57,7 +57,7 @@ static void bcm63xx_rng_cleanup(struct hwrng *rng)
 	val &= ~RNG_EN;
 	__raw_writel(val, priv->regs + RNG_CTRL);
 
-	clk_didsable_unprepare(prov->clk);
+	clk_disable_unprepare(priv->clk);
 }
 
 static int bcm63xx_rng_data_present(struct hwrng *rng, int wait)
@@ -97,14 +97,14 @@ static int bcm63xx_rng_probe(struct platform_device *pdev)
 	priv->rng.name = pdev->name;
 	priv->rng.init = bcm63xx_rng_init;
 	priv->rng.cleanup = bcm63xx_rng_cleanup;
-	prov->rng.data_present = bcm63xx_rng_data_present;
+	priv->rng.data_present = bcm63xx_rng_data_present;
 	priv->rng.data_read = bcm63xx_rng_data_read;
 
 	priv->clk = devm_clk_get(&pdev->dev, "ipsec");
 	if (IS_ERR(priv->clk)) {
-		error = PTR_ERR(priv->clk);
-		dev_err(&pdev->dev, "no clock for device: %d\n", error);
-		return error;
+		ret = PTR_ERR(priv->clk);
+		dev_err(&pdev->dev, "no clock for device: %d\n", ret);
+		return ret;
 	}
 
 	if (!devm_request_mem_region(&pdev->dev, r->start,
@@ -120,11 +120,11 @@ static int bcm63xx_rng_probe(struct platform_device *pdev)
 		return -ENOMEM;
 	}
 
-	error = devm_hwrng_register(&pdev->dev, &priv->rng);
-	if (error) {
+	ret = devm_hwrng_register(&pdev->dev, &priv->rng);
+	if (ret) {
 		dev_err(&pdev->dev, "failed to register rng device: %d\n",
-			error);
-		return error;
+			ret);
+		return ret;
 	}
 
 	dev_info(&pdev->dev, "registered RNG driver\n");
diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
@@ -9,10 +9,24 @@
 		   + __GNUC_MINOR__ * 100 \
 		   + __GNUC_PATCHLEVEL__)
 
-
 /* Optimization barrier */
+
 /* The "volatile" is due to gcc bugs */
 #define barrier() __asm__ __volatile__("": : :"memory")
+/*
+ * This version is i.e. to prevent dead stores elimination on @ptr
+ * where gcc and llvm may behave differently when otherwise using
+ * normal barrier(): while gcc behavior gets along with a normal
+ * barrier(), llvm needs an explicit input variable to be assumed
+ * clobbered. The issue is as follows: while the inline asm might
+ * access any memory it wants, the compiler could have fit all of
+ * @ptr into memory registers instead, and since @ptr never escaped
+ * from that, it proofed that the inline asm wasn't touching any of
+ * it. This version works well with both compilers, i.e. we're telling
+ * the compiler that the inline asm absolutely may see the contents
+ * of @ptr. See also: https://llvm.org/bugs/show_bug.cgi?id=15495
+ */
+#define barrier_data(ptr) __asm__ __volatile__("": :"r"(ptr) :"memory")
 
 /*
  * This macro obfuscates arithmetic on a variable address so that gcc
diff --git a/include/linux/compiler-intel.h b/include/linux/compiler-intel.h
@@ -13,9 +13,12 @@
 /* Intel ECC compiler doesn't support gcc specific asm stmts.
  * It uses intrinsics to do the equivalent things.
  */
+#undef barrier_data
 #undef RELOC_HIDE
 #undef OPTIMIZER_HIDE_VAR
 
+#define barrier_data(ptr) barrier()
+
 #define RELOC_HIDE(ptr, off)					\
   ({ unsigned long __ptr;					\
      __ptr = (unsigned long) (ptr);				\
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
@@ -169,6 +169,10 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect);
 # define barrier() __memory_barrier()
 #endif
 
+#ifndef barrier_data
+# define barrier_data(ptr) barrier()
+#endif
+
 /* Unreachable code */
 #ifndef unreachable
 # define unreachable() do { } while (1)
diff --git a/lib/string.c b/lib/string.c
@@ -607,7 +607,7 @@ EXPORT_SYMBOL(memset);
 void memzero_explicit(void *s, size_t count)
 {
 	memset(s, 0, count);
-	barrier();
+	barrier_data(s);
 }
 EXPORT_SYMBOL(memzero_explicit);
 

Original file line number	Diff line number	Diff line change
`@@ -607,7 +607,7 @@ EXPORT_SYMBOL(memset);`
`607`	`607`	`void memzero_explicit(void *s, size_t count)`
`608`	`608`	`{`
`609`	`609`	`memset(s, 0, count);`
`610`		`- barrier();`
	`610`	`+ barrier_data(s);`
`611`	`611`	`}`
`612`	`612`	`EXPORT_SYMBOL(memzero_explicit);`
`613`	`613`