[PATCH v4 02/15] objtool: Add ASM_STACK_FRAME_NON_STANDARD

Sami Tolvanen
2021-09-30T18:05:44Z

To use the STACK_FRAME_NON_STANDARD macro for a static symbol
defined in inline assembly, we need a C declaration that implies
global visibility. This type mismatch confuses the compiler with
CONFIG_CFI_CLANG. This change adds an inline assembly version of
the macro to avoid the issue.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
---
include/linux/objtool.h | 6 ++++++
tools/include/linux/objtool.h | 6 ++++++
2 files changed, 12 insertions(+)

diff --git a/include/linux/objtool.h b/include/linux/objtool.h
index 7e72d975cb76..080e95174536 100644
--- a/include/linux/objtool.h
+++ b/include/linux/objtool.h
@@ -66,6 +66,11 @@ struct unwind_hint {
static void __used __section(".discard.func_stack_frame_non_standard") \
*__func_stack_frame_non_standard_##func = func

+#define ASM_STACK_FRAME_NON_STANDARD(func) \
+ ".pushsection .discard.func_stack_frame_non_standard, \"aw\"\n" \
+ ".long " __stringify(func) " - .\n" \
+ ".popsection\n"
+
#else /* __ASSEMBLY__ */

/*
@@ -127,6 +132,7 @@ struct unwind_hint {
#define UNWIND_HINT(sp_reg, sp_offset, type, end) \
"\n\t"
#define STACK_FRAME_NON_STANDARD(func)
+#define ASM_STACK_FRAME_NON_STANDARD(func)
#else
#define ANNOTATE_INTRA_FUNCTION_CALL
.macro UNWIND_HINT sp_reg:req sp_offset=0 type:req end=0
diff --git a/tools/include/linux/objtool.h b/tools/include/linux/objtool.h
index 7e72d975cb76..080e95174536 100644
--- a/tools/include/linux/objtool.h
+++ b/tools/include/linux/objtool.h
@@ -66,6 +66,11 @@ struct unwind_hint {
static void __used __section(".discard.func_stack_frame_non_standard") \
*__func_stack_frame_non_standard_##func = func

+#define ASM_STACK_FRAME_NON_STANDARD(func) \
+ ".pushsection .discard.func_stack_frame_non_standard, \"aw\"\n" \
+ ".long " __stringify(func) " - .\n" \
+ ".popsection\n"
+
#else /* __ASSEMBLY__ */

/*
@@ -127,6 +132,7 @@ struct unwind_hint {
#define UNWIND_HINT(sp_reg, sp_offset, type, end) \
"\n\t"
#define STACK_FRAME_NON_STANDARD(func)
+#define ASM_STACK_FRAME_NON_STANDARD(func)
#else
#define ANNOTATE_INTRA_FUNCTION_CALL
.macro UNWIND_HINT sp_reg:req sp_offset=0 type:req end=0
--
2.33.0.800.g4c38ced690-goog