1 // SPDX-License-Identifier: GPL-2.0-only
3  * Copyright (C) 2022 - Google LLC
19 // This minimal DWARF CFI parser is partially based on the code in
21 // https://refspecs.linuxbase.org/LSB_4.0.0/LSB-Core-generic/LSB-Core-generic/ehframechpt.html
64 static void __always_inline scs_patch_loc(u64 loc)  in scs_patch_loc()  argument
66 	u32 insn = le32_to_cpup((void *)loc);  in scs_patch_loc()
70 		*(u32 *)loc = cpu_to_le32(SCS_PUSH);  in scs_patch_loc()
73 		*(u32 *)loc = cpu_to_le32(SCS_POP);  in scs_patch_loc()
88 		asm("dc civac, %0" :: "r"(loc));  in scs_patch_loc()
91 		    :: "r"(loc));  in scs_patch_loc()
104 		size--;  in skip_xleb128()
154 	int size = frame->size - offsetof(struct eh_frame, opcodes) + 4;  in scs_handle_fde_frame()
155 	u64 loc = (u64)offset_to_ptr(&frame->initial_loc);  in scs_handle_fde_frame()  local
156 	const u8 *opcode = frame->opcodes;  in scs_handle_fde_frame()
160 		loc = (u64)&frame->initial_loc64 + frame->initial_loc64;  in scs_handle_fde_frame()
161 		opcode = frame->opcodes64;  in scs_handle_fde_frame()
162 		size -= 8;  in scs_handle_fde_frame()
171 	size -= l + 1;  in scs_handle_fde_frame()
174 	 * Starting from 'loc', apply the CFA opcodes that advance the location  in scs_handle_fde_frame()
177 	while (size-- > 0) {  in scs_handle_fde_frame()
185 			loc += *opcode++ * code_alignment_factor;  in scs_handle_fde_frame()
186 			size--;  in scs_handle_fde_frame()
190 			loc += *opcode++ * code_alignment_factor;  in scs_handle_fde_frame()
191 			loc += (*opcode++ << 8) * code_alignment_factor;  in scs_handle_fde_frame()
192 			size -= 2;  in scs_handle_fde_frame()
210 				scs_patch_loc(loc - 4);  in scs_handle_fde_frame()
214 			// advance loc  in scs_handle_fde_frame()
215 			loc += (opcode[-1] & 0x3f) * code_alignment_factor;  in scs_handle_fde_frame()
238 		if (frame->size == 0 ||  in scs_patch()
239 		    frame->size == U32_MAX ||  in scs_patch()
240 		    frame->size > size)  in scs_patch()
243 		if (frame->cie_id_or_pointer == 0) {  in scs_patch()
249 			if (strcmp(frame->augmentation_string, "zR"))  in scs_patch()
253 			 * The code alignment factor is a uleb128 encoded field  in scs_patch()
260 			if ((frame->code_alignment_factor & BIT(7)) ||  in scs_patch()
261 			    (frame->data_alignment_factor & BIT(7)) ||  in scs_patch()
262 			    frame->return_address_register != 30 ||  in scs_patch()
263 			    frame->augmentation_data_size != 1)  in scs_patch()
266 			code_alignment_factor = frame->code_alignment_factor;  in scs_patch()
268 			switch (frame->fde_pointer_format) {  in scs_patch()
287 		p += sizeof(frame->size) + frame->size;  in scs_patch()
288 		size -= sizeof(frame->size) + frame->size;  in scs_patch()