[PATCH 5.10 073/221] gcov: fix clang-11+ support

From: Greg Kroah-Hartman
Date: Mon Mar 29 2021 - 04:31:30 EST


From: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>

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@xxxxxxxxxx
Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Reported-by: Prasad Sodagudi <psodagud@xxxxxxxxxxx>
Suggested-by: Nathan Chancellor <nathan@xxxxxxxxxx>
Reviewed-by: Fangrui Song <maskray@xxxxxxxxxx>
Tested-by: Nathan Chancellor <nathan@xxxxxxxxxx>
Acked-by: Peter Oberparleiter <oberpar@xxxxxxxxxxxxx>
Reviewed-by: Nathan Chancellor <nathan@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> [5.4+]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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