arm64: Dynamic shadow call stack fixes

index 2e010ea76be2..934e9217cd74 100644
@@ -46,6 +46,13 @@ static inline void dynamic_scs_init(void)
 static inline void dynamic_scs_init(void) {}
 #endif
 
+enum {
+	EDYNSCS_INVALID_CIE_HEADER		= 1,
+	EDYNSCS_INVALID_CIE_SDATA_SIZE		= 2,
+	EDYNSCS_INVALID_FDE_AUGM_DATA_SIZE	= 3,
+	EDYNSCS_INVALID_CFA_OPCODE		= 4,
+};
+
 int __pi_scs_patch(const u8 eh_frame[], int size);
 asmlinkage void __pi_scs_patch_vmlinux(void);
 

index 36b25af56324..06bb680bfe97 100644
@@ -462,14 +462,20 @@ int module_finalize(const Elf_Ehdr *hdr,
 		    struct module *me)
 {
 	const Elf_Shdr *s;
+	int ret;
+
 	s = find_section(hdr, sechdrs, ".altinstructions");
 	if (s)
 		apply_alternatives_module((void *)s->sh_addr, s->sh_size);
 
 	if (scs_is_dynamic()) {
 		s = find_section(hdr, sechdrs, ".init.eh_frame");
-		if (s)
-			__pi_scs_patch((void *)s->sh_addr, s->sh_size);
+		if (s) {
+			ret = __pi_scs_patch((void *)s->sh_addr, s->sh_size);
+			if (ret)
+				pr_err("module %s: error occurred during dynamic SCS patching (%d)\n",
+				       me->name, ret);
+		}
 	}
 
 	return module_init_ftrace_plt(hdr, sechdrs, me);

114 lines not on this page · raw message

index cec8f0a52bbc..55d0cd64ef71 100644
@@ -50,6 +50,10 @@ bool dynamic_scs_is_enabled;
 #define DW_CFA_GNU_negative_offset_extended 0x2f
 #define DW_CFA_hi_user                      0x3f
 
+#define DW_EH_PE_sdata4                     0x0b
+#define DW_EH_PE_sdata8                     0x0c
+#define DW_EH_PE_pcrel                      0x10
+
 enum {
 	PACIASP		= 0xd503233f,
 	AUTIASP		= 0xd50323bf,

@@ -125,6 +129,7 @@ struct eh_frame {
 			u8	data_alignment_factor;
 			u8	return_address_register;
 			u8	augmentation_data_size;
+			u8	fde_pointer_format;
 		};
 
 		struct { // FDE

@@ -132,11 +137,18 @@ struct eh_frame {
 			s32	range;
 			u8	opcodes[];
 		};
+
+		struct { // FDE
+			s64	initial_loc64;
+			s64	range64;
+			u8	opcodes64[];
+		};
 	};
 };
 
 static int scs_handle_fde_frame(const struct eh_frame *frame,
 				int code_alignment_factor,
+				bool use_sdata8,
 				bool dry_run)
 {
 	int size = frame->size - offsetof(struct eh_frame, opcodes) + 4;

@@ -144,6 +156,12 @@ static int scs_handle_fde_frame(const struct eh_frame *frame,
 	const u8 *opcode = frame->opcodes;
 	int l;
 
+	if (use_sdata8) {
+		loc = (u64)&frame->initial_loc64 + frame->initial_loc64;
+		opcode = frame->opcodes64;
+		size -= 8;
+	}
+
 	// assume single byte uleb128_t for augmentation data size
 	if (*opcode & BIT(7))
 		return EDYNSCS_INVALID_FDE_AUGM_DATA_SIZE;

@@ -210,6 +228,7 @@ static int scs_handle_fde_frame(const struct eh_frame *frame,
 int scs_patch(const u8 eh_frame[], int size)
 {
 	int code_alignment_factor = 1;
+	bool fde_use_sdata8 = false;
 	const u8 *p = eh_frame;
 
 	while (size > 4) {

@@ -245,13 +264,24 @@ int scs_patch(const u8 eh_frame[], int size)
 				return EDYNSCS_INVALID_CIE_HEADER;
 
 			code_alignment_factor = frame->code_alignment_factor;
+
+			switch (frame->fde_pointer_format) {
+			case DW_EH_PE_pcrel | DW_EH_PE_sdata4:
+				fde_use_sdata8 = false;
+				break;
+			case DW_EH_PE_pcrel | DW_EH_PE_sdata8:
+				fde_use_sdata8 = true;
+				break;
+			default:
+				return EDYNSCS_INVALID_CIE_SDATA_SIZE;
+			}
 		} else {
 			ret = scs_handle_fde_frame(frame, code_alignment_factor,
-						   true);
+						   fde_use_sdata8, true);
 			if (ret)
 				return ret;
 			scs_handle_fde_frame(frame, code_alignment_factor,
-					     false);
+					     fde_use_sdata8, false);
 		}
 
 		p += sizeof(frame->size) + frame->size;

index 934e9217cd74..a76f9b387a26 100644
@@ -54,7 +54,6 @@ enum {
 };
 
 int __pi_scs_patch(const u8 eh_frame[], int size);
-asmlinkage void __pi_scs_patch_vmlinux(void);
 
 #endif /* __ASSEMBLY __ */