linux-kernel - [PATCH 5.4 044/111] gcov: fix clang-11+ support

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Date:   Mon, 29 Mar 2021 09:57:52 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Nick Desaulniers <ndesaulniers@...gle.com>,
        Prasad Sodagudi <psodagud@...cinc.com>,
        Nathan Chancellor <nathan@...nel.org>,
        Fangrui Song <maskray@...gle.com>,
        Peter Oberparleiter <oberpar@...ux.ibm.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>
Subject: [PATCH 5.4 044/111] gcov: fix clang-11+ support

From: Nick Desaulniers <ndesaulniers@...gle.com>

commit 60bcf728ee7c60ac2a1f9a0eaceb3a7b3954cd2b upstream.

LLVM changed the expected function signatures for llvm_gcda_start_file()
and llvm_gcda_emit_function() in the clang-11 release.  Users of
clang-11 or newer may have noticed their kernels failing to boot due to
a panic when enabling CONFIG_GCOV_KERNEL=y +CONFIG_GCOV_PROFILE_ALL=y.
Fix up the function signatures so calling these functions doesn't panic
the kernel.

Link: https://reviews.llvm.org/rGcdd683b516d147925212724b09ec6fb792a40041
Link: https://reviews.llvm.org/rG13a633b438b6500ecad9e4f936ebadf3411d0f44
Link: https://lkml.kernel.org/r/20210312224132.3413602-2-ndesaulniers@google.com
Signed-off-by: Nick Desaulniers <ndesaulniers@...gle.com>
Reported-by: Prasad Sodagudi <psodagud@...cinc.com>
Suggested-by: Nathan Chancellor <nathan@...nel.org>
Reviewed-by: Fangrui Song <maskray@...gle.com>
Tested-by: Nathan Chancellor <nathan@...nel.org>
Acked-by: Peter Oberparleiter <oberpar@...ux.ibm.com>
Reviewed-by: Nathan Chancellor <nathan@...nel.org>
Cc: <stable@...r.kernel.org>	[5.4+]
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 kernel/gcov/clang.c |   69 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 69 insertions(+)

--- a/kernel/gcov/clang.c
+++ b/kernel/gcov/clang.c
@@ -75,7 +75,9 @@ struct gcov_fn_info {
 
 	u32 num_counters;
 	u64 *counters;
+#if CONFIG_CLANG_VERSION < 110000
 	const char *function_name;
+#endif
 };
 
 static struct gcov_info *current_info;
@@ -105,6 +107,7 @@ void llvm_gcov_init(llvm_gcov_callback w
 }
 EXPORT_SYMBOL(llvm_gcov_init);
 
+#if CONFIG_CLANG_VERSION < 110000
 void llvm_gcda_start_file(const char *orig_filename, const char version[4],
 		u32 checksum)
 {
@@ -113,7 +116,17 @@ void llvm_gcda_start_file(const char *or
 	current_info->checksum = checksum;
 }
 EXPORT_SYMBOL(llvm_gcda_start_file);
+#else
+void llvm_gcda_start_file(const char *orig_filename, u32 version, u32 checksum)
+{
+	current_info->filename = orig_filename;
+	current_info->version = version;
+	current_info->checksum = checksum;
+}
+EXPORT_SYMBOL(llvm_gcda_start_file);
+#endif
 
+#if CONFIG_CLANG_VERSION < 110000
 void llvm_gcda_emit_function(u32 ident, const char *function_name,
 		u32 func_checksum, u8 use_extra_checksum, u32 cfg_checksum)
 {
@@ -133,6 +146,24 @@ void llvm_gcda_emit_function(u32 ident,
 	list_add_tail(&info->head, &current_info->functions);
 }
 EXPORT_SYMBOL(llvm_gcda_emit_function);
+#else
+void llvm_gcda_emit_function(u32 ident, u32 func_checksum,
+		u8 use_extra_checksum, u32 cfg_checksum)
+{
+	struct gcov_fn_info *info = kzalloc(sizeof(*info), GFP_KERNEL);
+
+	if (!info)
+		return;
+
+	INIT_LIST_HEAD(&info->head);
+	info->ident = ident;
+	info->checksum = func_checksum;
+	info->use_extra_checksum = use_extra_checksum;
+	info->cfg_checksum = cfg_checksum;
+	list_add_tail(&info->head, &current_info->functions);
+}
+EXPORT_SYMBOL(llvm_gcda_emit_function);
+#endif
 
 void llvm_gcda_emit_arcs(u32 num_counters, u64 *counters)
 {
@@ -295,6 +326,7 @@ void gcov_info_add(struct gcov_info *dst
 	}
 }
 
+#if CONFIG_CLANG_VERSION < 110000
 static struct gcov_fn_info *gcov_fn_info_dup(struct gcov_fn_info *fn)
 {
 	size_t cv_size; /* counter values size */
@@ -322,6 +354,28 @@ err_name:
 	kfree(fn_dup);
 	return NULL;
 }
+#else
+static struct gcov_fn_info *gcov_fn_info_dup(struct gcov_fn_info *fn)
+{
+	size_t cv_size; /* counter values size */
+	struct gcov_fn_info *fn_dup = kmemdup(fn, sizeof(*fn),
+			GFP_KERNEL);
+	if (!fn_dup)
+		return NULL;
+	INIT_LIST_HEAD(&fn_dup->head);
+
+	cv_size = fn->num_counters * sizeof(fn->counters[0]);
+	fn_dup->counters = vmalloc(cv_size);
+	if (!fn_dup->counters) {
+		kfree(fn_dup);
+		return NULL;
+	}
+
+	memcpy(fn_dup->counters, fn->counters, cv_size);
+
+	return fn_dup;
+}
+#endif
 
 /**
  * gcov_info_dup - duplicate profiling data set
@@ -362,6 +416,7 @@ err:
  * gcov_info_free - release memory for profiling data set duplicate
  * @info: profiling data set duplicate to free
  */
+#if CONFIG_CLANG_VERSION < 110000
 void gcov_info_free(struct gcov_info *info)
 {
 	struct gcov_fn_info *fn, *tmp;
@@ -375,6 +430,20 @@ void gcov_info_free(struct gcov_info *in
 	kfree(info->filename);
 	kfree(info);
 }
+#else
+void gcov_info_free(struct gcov_info *info)
+{
+	struct gcov_fn_info *fn, *tmp;
+
+	list_for_each_entry_safe(fn, tmp, &info->functions, head) {
+		vfree(fn->counters);
+		list_del(&fn->head);
+		kfree(fn);
+	}
+	kfree(info->filename);
+	kfree(info);
+}
+#endif
 
 #define ITER_STRIDE	PAGE_SIZE