Merge 5.18-rc5 into char-misc-next

We need the char-misc fixes in here as well.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

3 files changed, 29 insertions, 19 deletions

diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 9717e6f6fb31..33c1ed581522 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -231,7 +231,7 @@ objtool_args =								\
 	$(if $(part-of-module), --module)				\
 	$(if $(CONFIG_X86_KERNEL_IBT), --lto --ibt)			\
 	$(if $(CONFIG_FRAME_POINTER),, --no-fp)				\
-	$(if $(CONFIG_GCOV_KERNEL)$(CONFIG_LTO_CLANG), --no-unreachable)\
+	$(if $(CONFIG_GCOV_KERNEL), --no-unreachable)			\
 	$(if $(CONFIG_RETPOLINE), --retpoline)				\
 	$(if $(CONFIG_X86_SMAP), --uaccess)				\
 	$(if $(CONFIG_FTRACE_MCOUNT_USE_OBJTOOL), --mcount)		\
diff --git a/scripts/gcc-plugins/latent_entropy_plugin.c b/scripts/gcc-plugins/latent_entropy_plugin.c
index 589454bce930..8425da41de0d 100644
--- a/scripts/gcc-plugins/latent_entropy_plugin.c
+++ b/scripts/gcc-plugins/latent_entropy_plugin.c
@@ -86,25 +86,31 @@ static struct plugin_info latent_entropy_plugin_info = {
 	.help		= "disable\tturn off latent entropy instrumentation\n",
 };
 
-static unsigned HOST_WIDE_INT seed;
-/*
- * get_random_seed() (this is a GCC function) generates the seed.
- * This is a simple random generator without any cryptographic security because
- * the entropy doesn't come from here.
- */
+static unsigned HOST_WIDE_INT deterministic_seed;
+static unsigned HOST_WIDE_INT rnd_buf[32];
+static size_t rnd_idx = ARRAY_SIZE(rnd_buf);
+static int urandom_fd = -1;
+
 static unsigned HOST_WIDE_INT get_random_const(void)
 {
-	unsigned int i;
-	unsigned HOST_WIDE_INT ret = 0;
-
-	for (i = 0; i < 8 * sizeof(ret); i++) {
-		ret = (ret << 1) | (seed & 1);
-		seed >>= 1;
-		if (ret & 1)
-			seed ^= 0xD800000000000000ULL;
+	if (deterministic_seed) {
+		unsigned HOST_WIDE_INT w = deterministic_seed;
+		w ^= w << 13;
+		w ^= w >> 7;
+		w ^= w << 17;
+		deterministic_seed = w;
+		return deterministic_seed;
 	}
 
-	return ret;
+	if (urandom_fd < 0) {
+		urandom_fd = open("/dev/urandom", O_RDONLY);
+		gcc_assert(urandom_fd >= 0);
+	}
+	if (rnd_idx >= ARRAY_SIZE(rnd_buf)) {
+		gcc_assert(read(urandom_fd, rnd_buf, sizeof(rnd_buf)) == sizeof(rnd_buf));
+		rnd_idx = 0;
+	}
+	return rnd_buf[rnd_idx++];
 }
 
 static tree tree_get_random_const(tree type)
@@ -537,8 +543,6 @@ static void latent_entropy_start_unit(void *gcc_data __unused,
 	tree type, id;
 	int quals;
 
-	seed = get_random_seed(false);
-
 	if (in_lto_p)
 		return;
 
@@ -573,6 +577,12 @@ __visible int plugin_init(struct plugin_name_args *plugin_info,
 	const struct plugin_argument * const argv = plugin_info->argv;
 	int i;
 
+	/*
+	 * Call get_random_seed() with noinit=true, so that this returns
+	 * 0 in the case where no seed has been passed via -frandom-seed.
+	 */
+	deterministic_seed = get_random_seed(true);
+
 	static const struct ggc_root_tab gt_ggc_r_gt_latent_entropy[] = {
 		{
 			.base = &latent_entropy_decl,
diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index 20f44504a644..9361a1ef02c9 100755
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -140,7 +140,7 @@ objtool_link()
 		if ! is_enabled CONFIG_FRAME_POINTER; then
 			objtoolopt="${objtoolopt} --no-fp"
 		fi
-		if is_enabled CONFIG_GCOV_KERNEL || is_enabled CONFIG_LTO_CLANG; then
+		if is_enabled CONFIG_GCOV_KERNEL; then
 			objtoolopt="${objtoolopt} --no-unreachable"
 		fi
 		if is_enabled CONFIG_RETPOLINE; then