gcov: fix clang-11+ support

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@google.com>
Reported-by: Prasad Sodagudi <psodagud@quicinc.com>
Suggested-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Fangrui Song <maskray@google.com>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Cc: <stable@vger.kernel.org>	[5.4+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/kernel/gcov/clang.c b/kernel/gcov/clang.c
index c94b820a1b62c59e76a089393761aaf2445b09b8..8743150db2acc527f6b253131388281530c68b3e 100644 (file)
--- 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 writeout, llvm_gcov_callback flush)
 }
 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 *orig_filename, const char version[4],
        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, const char *function_name,
        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, struct gcov_info *src)
        }
 }
 
+#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 @@ static struct gcov_fn_info *gcov_fn_info_dup(struct gcov_fn_info *fn)
        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 @@ struct gcov_info *gcov_info_dup(struct gcov_info *info)
  * 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 *info)
        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