X-Git-Url: https://review.openocd.org/gitweb?p=openocd.git;a=blobdiff_plain;f=src%2Ftarget%2Farm_semihosting.c;h=9117a74426b056cbb487c4f1b969578dd5ea0657;hp=f31f901f0b7bd328e19f7319f796aab2645d1780;hb=a851b91c4c1db76dd1e26a7d1a99124ad456b020;hpb=ef49b34b2af5bae85e5ee887c49eed02eb227feb

diff --git a/src/target/arm_semihosting.c b/src/target/arm_semihosting.c
index f31f901f0b..9117a74426 100644
--- a/src/target/arm_semihosting.c
+++ b/src/target/arm_semihosting.c
@@ -8,6 +8,9 @@
  *   Copyright (C) 2016 by Square, Inc.                                    *
  *   Steven Stallion <stallion@squareup.com>                               *
  *                                                                         *
+ *   Copyright (C) 2018 by Liviu Ionescu                                   *
+ *   <ilg@livius.net>                                                      *
+ *                                                                         *
  *   This program is free software; you can redistribute it and/or modify  *
  *   it under the terms of the GNU General Public License as published by  *
  *   the Free Software Foundation; either version 2 of the License, or     *
@@ -43,6 +46,7 @@
 #include "arm7_9_common.h"
 #include "armv7m.h"
 #include "armv7a.h"
+#include "armv8.h"
 #include "cortex_m.h"
 #include "register.h"
 #include "arm_opcodes.h"
@@ -52,25 +56,35 @@
 #include <helper/log.h>
 #include <sys/stat.h>
 
-static const int open_modeflags[12] = {
-	O_RDONLY,
-	O_RDONLY | O_BINARY,
-	O_RDWR,
-	O_RDWR | O_BINARY,
-	O_WRONLY | O_CREAT | O_TRUNC,
-	O_WRONLY | O_CREAT | O_TRUNC | O_BINARY,
-	O_RDWR | O_CREAT | O_TRUNC,
-	O_RDWR | O_CREAT | O_TRUNC | O_BINARY,
-	O_WRONLY | O_CREAT | O_APPEND,
-	O_WRONLY | O_CREAT | O_APPEND | O_BINARY,
-	O_RDWR | O_CREAT | O_APPEND,
-	O_RDWR | O_CREAT | O_APPEND | O_BINARY
-};
+static int arm_semihosting_resume(struct target *target, int *retval)
+{
+	if (is_armv8(target_to_armv8(target))) {
+		struct armv8_common *armv8 = target_to_armv8(target);
+		if (armv8->last_run_control_op == ARMV8_RUNCONTROL_RESUME) {
+			*retval = target_resume(target, 1, 0, 0, 0);
+			if (*retval != ERROR_OK) {
+				LOG_ERROR("Failed to resume target");
+				return 0;
+			}
+		} else if (armv8->last_run_control_op == ARMV8_RUNCONTROL_STEP)
+			target->debug_reason = DBG_REASON_SINGLESTEP;
+	} else {
+		*retval = target_resume(target, 1, 0, 0, 0);
+		if (*retval != ERROR_OK) {
+			LOG_ERROR("Failed to resume target");
+			return 0;
+		}
+	}
+	return 1;
+}
 
 static int post_result(struct target *target)
 {
 	struct arm *arm = target_to_arm(target);
 
+	if (!target->semihosting)
+		return ERROR_FAIL;
+
 	/* REVISIT this looks wrong ... ARM11 and Cortex-A8
 	 * should work this way at least sometimes.
 	 */
@@ -79,7 +93,7 @@ static int post_result(struct target *target)
 		uint32_t spsr;
 
 		/* return value in R0 */
-		buf_set_u32(arm->core_cache->reg_list[0].value, 0, 32, arm->semihosting_result);
+		buf_set_u32(arm->core_cache->reg_list[0].value, 0, 32, target->semihosting->result);
 		arm->core_cache->reg_list[0].dirty = 1;
 
 		/* LR --> PC */
@@ -100,528 +114,28 @@ static int post_result(struct target *target)
 		if (spsr & 0x20)
 			arm->core_state = ARM_STATE_THUMB;
 
+	} else if (is_armv8(target_to_armv8(target))) {
+		if (arm->core_state == ARM_STATE_AARCH64) {
+			/* return value in R0 */
+			buf_set_u64(arm->core_cache->reg_list[0].value, 0, 64, target->semihosting->result);
+			arm->core_cache->reg_list[0].dirty = 1;
+
+			uint64_t pc = buf_get_u64(arm->core_cache->reg_list[32].value, 0, 64);
+			buf_set_u64(arm->pc->value, 0, 64, pc + 4);
+			arm->pc->dirty = 1;
+		}
 	} else {
 		/* resume execution, this will be pc+2 to skip over the
 		 * bkpt instruction */
 
 		/* return result in R0 */
-		buf_set_u32(arm->core_cache->reg_list[0].value, 0, 32, arm->semihosting_result);
+		buf_set_u32(arm->core_cache->reg_list[0].value, 0, 32, target->semihosting->result);
 		arm->core_cache->reg_list[0].dirty = 1;
 	}
 
 	return ERROR_OK;
 }
 
-static int do_semihosting(struct target *target)
-{
-	struct arm *arm = target_to_arm(target);
-	struct gdb_fileio_info *fileio_info = target->fileio_info;
-	uint32_t r0 = buf_get_u32(arm->core_cache->reg_list[0].value, 0, 32);
-	uint32_t r1 = buf_get_u32(arm->core_cache->reg_list[1].value, 0, 32);
-	uint8_t params[16];
-	int retval;
-
-	/*
-	 * TODO: lots of security issues are not considered yet, such as:
-	 * - no validation on target provided file descriptors
-	 * - no safety checks on opened/deleted/renamed file paths
-	 * Beware the target app you use this support with.
-	 *
-	 * TODO: unsupported semihosting fileio operations could be
-	 * implemented if we had a small working area at our disposal.
-	 */
-	switch ((arm->semihosting_op = r0)) {
-	case 0x01:	/* SYS_OPEN */
-		retval = target_read_memory(target, r1, 4, 3, params);
-		if (retval != ERROR_OK)
-			return retval;
-		else {
-			uint32_t a = target_buffer_get_u32(target, params+0);
-			uint32_t m = target_buffer_get_u32(target, params+4);
-			uint32_t l = target_buffer_get_u32(target, params+8);
-			uint8_t fn[256];
-			retval = target_read_memory(target, a, 1, l, fn);
-			if (retval != ERROR_OK)
-				return retval;
-			fn[l] = 0;
-			if (arm->is_semihosting_fileio) {
-				if (strcmp((char *)fn, ":tt") == 0)
-					arm->semihosting_result = 0;
-				else {
-					arm->semihosting_hit_fileio = true;
-					fileio_info->identifier = "open";
-					fileio_info->param_1 = a;
-					fileio_info->param_2 = l;
-					fileio_info->param_3 = open_modeflags[m];
-					fileio_info->param_4 = 0644;
-				}
-			} else {
-				if (l <= 255 && m <= 11) {
-					if (strcmp((char *)fn, ":tt") == 0) {
-						if (m < 4)
-							arm->semihosting_result = dup(STDIN_FILENO);
-						else
-							arm->semihosting_result = dup(STDOUT_FILENO);
-					} else {
-						/* cygwin requires the permission setting
-						 * otherwise it will fail to reopen a previously
-						 * written file */
-						arm->semihosting_result = open((char *)fn, open_modeflags[m], 0644);
-					}
-					arm->semihosting_errno =  errno;
-				} else {
-					arm->semihosting_result = -1;
-					arm->semihosting_errno = EINVAL;
-				}
-			}
-		}
-		break;
-
-	case 0x02:	/* SYS_CLOSE */
-		retval = target_read_memory(target, r1, 4, 1, params);
-		if (retval != ERROR_OK)
-			return retval;
-		else {
-			int fd = target_buffer_get_u32(target, params+0);
-			if (arm->is_semihosting_fileio) {
-				arm->semihosting_hit_fileio = true;
-				fileio_info->identifier = "close";
-				fileio_info->param_1 = fd;
-			} else {
-				arm->semihosting_result = close(fd);
-				arm->semihosting_errno = errno;
-			}
-		}
-		break;
-
-	case 0x03:	/* SYS_WRITEC */
-		if (arm->is_semihosting_fileio) {
-			arm->semihosting_hit_fileio = true;
-			fileio_info->identifier = "write";
-			fileio_info->param_1 = 1;
-			fileio_info->param_2 = r1;
-			fileio_info->param_3 = 1;
-		} else {
-			unsigned char c;
-			retval = target_read_memory(target, r1, 1, 1, &c);
-			if (retval != ERROR_OK)
-				return retval;
-			putchar(c);
-			arm->semihosting_result = 0;
-		}
-		break;
-
-	case 0x04:	/* SYS_WRITE0 */
-		if (arm->is_semihosting_fileio) {
-			size_t count = 0;
-			for (uint32_t a = r1;; a++) {
-				unsigned char c;
-				retval = target_read_memory(target, a, 1, 1, &c);
-				if (retval != ERROR_OK)
-					return retval;
-				if (c == '\0')
-					break;
-				count++;
-			}
-			arm->semihosting_hit_fileio = true;
-			fileio_info->identifier = "write";
-			fileio_info->param_1 = 1;
-			fileio_info->param_2 = r1;
-			fileio_info->param_3 = count;
-		} else {
-			do {
-				unsigned char c;
-				retval = target_read_memory(target, r1++, 1, 1, &c);
-				if (retval != ERROR_OK)
-					return retval;
-				if (!c)
-					break;
-				putchar(c);
-			} while (1);
-			arm->semihosting_result = 0;
-		}
-		break;
-
-	case 0x05:	/* SYS_WRITE */
-		retval = target_read_memory(target, r1, 4, 3, params);
-		if (retval != ERROR_OK)
-			return retval;
-		else {
-			int fd = target_buffer_get_u32(target, params+0);
-			uint32_t a = target_buffer_get_u32(target, params+4);
-			size_t l = target_buffer_get_u32(target, params+8);
-			if (arm->is_semihosting_fileio) {
-				arm->semihosting_hit_fileio = true;
-				fileio_info->identifier = "write";
-				fileio_info->param_1 = fd;
-				fileio_info->param_2 = a;
-				fileio_info->param_3 = l;
-			} else {
-				uint8_t *buf = malloc(l);
-				if (!buf) {
-					arm->semihosting_result = -1;
-					arm->semihosting_errno = ENOMEM;
-				} else {
-					retval = target_read_buffer(target, a, l, buf);
-					if (retval != ERROR_OK) {
-						free(buf);
-						return retval;
-					}
-					arm->semihosting_result = write(fd, buf, l);
-					arm->semihosting_errno = errno;
-					if (arm->semihosting_result >= 0)
-						arm->semihosting_result = l - arm->semihosting_result;
-					free(buf);
-				}
-			}
-		}
-		break;
-
-	case 0x06:	/* SYS_READ */
-		retval = target_read_memory(target, r1, 4, 3, params);
-		if (retval != ERROR_OK)
-			return retval;
-		else {
-			int fd = target_buffer_get_u32(target, params+0);
-			uint32_t a = target_buffer_get_u32(target, params+4);
-			ssize_t l = target_buffer_get_u32(target, params+8);
-			if (arm->is_semihosting_fileio) {
-				arm->semihosting_hit_fileio = true;
-				fileio_info->identifier = "read";
-				fileio_info->param_1 = fd;
-				fileio_info->param_2 = a;
-				fileio_info->param_3 = l;
-			} else {
-				uint8_t *buf = malloc(l);
-				if (!buf) {
-					arm->semihosting_result = -1;
-					arm->semihosting_errno = ENOMEM;
-				} else {
-					arm->semihosting_result = read(fd, buf, l);
-					arm->semihosting_errno = errno;
-					if (arm->semihosting_result >= 0) {
-						retval = target_write_buffer(target, a, arm->semihosting_result, buf);
-						if (retval != ERROR_OK) {
-							free(buf);
-							return retval;
-						}
-						arm->semihosting_result = l - arm->semihosting_result;
-					}
-					free(buf);
-				}
-			}
-		}
-		break;
-
-	case 0x07:	/* SYS_READC */
-		if (arm->is_semihosting_fileio) {
-			LOG_ERROR("SYS_READC not supported by semihosting fileio");
-			return ERROR_FAIL;
-		}
-		arm->semihosting_result = getchar();
-		break;
-
-	case 0x08:	/* SYS_ISERROR */
-		retval = target_read_memory(target, r1, 4, 1, params);
-		if (retval != ERROR_OK)
-			return retval;
-		arm->semihosting_result = (target_buffer_get_u32(target, params+0) != 0);
-		break;
-
-	case 0x09:	/* SYS_ISTTY */
-		if (arm->is_semihosting_fileio) {
-			arm->semihosting_hit_fileio = true;
-			fileio_info->identifier = "isatty";
-			fileio_info->param_1 = r1;
-		} else {
-			retval = target_read_memory(target, r1, 4, 1, params);
-			if (retval != ERROR_OK)
-				return retval;
-			arm->semihosting_result = isatty(target_buffer_get_u32(target, params+0));
-		}
-		break;
-
-	case 0x0a:	/* SYS_SEEK */
-		retval = target_read_memory(target, r1, 4, 2, params);
-		if (retval != ERROR_OK)
-			return retval;
-		else {
-			int fd = target_buffer_get_u32(target, params+0);
-			off_t pos = target_buffer_get_u32(target, params+4);
-			if (arm->is_semihosting_fileio) {
-				arm->semihosting_hit_fileio = true;
-				fileio_info->identifier = "lseek";
-				fileio_info->param_1 = fd;
-				fileio_info->param_2 = pos;
-				fileio_info->param_3 = SEEK_SET;
-			} else {
-				arm->semihosting_result = lseek(fd, pos, SEEK_SET);
-				arm->semihosting_errno = errno;
-				if (arm->semihosting_result == pos)
-					arm->semihosting_result = 0;
-			}
-		}
-		break;
-
-	case 0x0c:	/* SYS_FLEN */
-		if (arm->is_semihosting_fileio) {
-			LOG_ERROR("SYS_FLEN not supported by semihosting fileio");
-			return ERROR_FAIL;
-		}
-		retval = target_read_memory(target, r1, 4, 1, params);
-		if (retval != ERROR_OK)
-			return retval;
-		else {
-			int fd = target_buffer_get_u32(target, params+0);
-			struct stat buf;
-			arm->semihosting_result = fstat(fd, &buf);
-			if (arm->semihosting_result == -1) {
-				arm->semihosting_errno = errno;
-				arm->semihosting_result = -1;
-				break;
-			}
-			arm->semihosting_result = buf.st_size;
-		}
-		break;
-
-	case 0x0e:	/* SYS_REMOVE */
-		retval = target_read_memory(target, r1, 4, 2, params);
-		if (retval != ERROR_OK)
-			return retval;
-		else {
-			uint32_t a = target_buffer_get_u32(target, params+0);
-			uint32_t l = target_buffer_get_u32(target, params+4);
-			if (arm->is_semihosting_fileio) {
-				arm->semihosting_hit_fileio = true;
-				fileio_info->identifier = "unlink";
-				fileio_info->param_1 = a;
-				fileio_info->param_2 = l;
-			} else {
-				if (l <= 255) {
-					uint8_t fn[256];
-					retval = target_read_memory(target, a, 1, l, fn);
-					if (retval != ERROR_OK)
-						return retval;
-					fn[l] = 0;
-					arm->semihosting_result = remove((char *)fn);
-					arm->semihosting_errno =  errno;
-				} else {
-					arm->semihosting_result = -1;
-					arm->semihosting_errno = EINVAL;
-				}
-			}
-		}
-		break;
-
-	case 0x0f:	/* SYS_RENAME */
-		retval = target_read_memory(target, r1, 4, 4, params);
-		if (retval != ERROR_OK)
-			return retval;
-		else {
-			uint32_t a1 = target_buffer_get_u32(target, params+0);
-			uint32_t l1 = target_buffer_get_u32(target, params+4);
-			uint32_t a2 = target_buffer_get_u32(target, params+8);
-			uint32_t l2 = target_buffer_get_u32(target, params+12);
-			if (arm->is_semihosting_fileio) {
-				arm->semihosting_hit_fileio = true;
-				fileio_info->identifier = "rename";
-				fileio_info->param_1 = a1;
-				fileio_info->param_2 = l1;
-				fileio_info->param_3 = a2;
-				fileio_info->param_4 = l2;
-			} else {
-				if (l1 <= 255 && l2 <= 255) {
-					uint8_t fn1[256], fn2[256];
-					retval = target_read_memory(target, a1, 1, l1, fn1);
-					if (retval != ERROR_OK)
-						return retval;
-					retval = target_read_memory(target, a2, 1, l2, fn2);
-					if (retval != ERROR_OK)
-						return retval;
-					fn1[l1] = 0;
-					fn2[l2] = 0;
-					arm->semihosting_result = rename((char *)fn1, (char *)fn2);
-					arm->semihosting_errno =  errno;
-				} else {
-					arm->semihosting_result = -1;
-					arm->semihosting_errno = EINVAL;
-				}
-			}
-		}
-		break;
-
-	case 0x11:	/* SYS_TIME */
-		arm->semihosting_result = time(NULL);
-		break;
-
-	case 0x13:	/* SYS_ERRNO */
-		arm->semihosting_result = arm->semihosting_errno;
-		break;
-
-	case 0x15:	/* SYS_GET_CMDLINE */
-		retval = target_read_memory(target, r1, 4, 2, params);
-		if (retval != ERROR_OK)
-			return retval;
-		else {
-			uint32_t a = target_buffer_get_u32(target, params+0);
-			uint32_t l = target_buffer_get_u32(target, params+4);
-			char *arg = arm->semihosting_cmdline != NULL ? arm->semihosting_cmdline : "";
-			uint32_t s = strlen(arg) + 1;
-			if (l < s)
-				arm->semihosting_result = -1;
-			else {
-				retval = target_write_buffer(target, a, s, (uint8_t *)arg);
-				if (retval != ERROR_OK)
-					return retval;
-				arm->semihosting_result = 0;
-			}
-		}
-		break;
-
-	case 0x16:	/* SYS_HEAPINFO */
-		retval = target_read_memory(target, r1, 4, 1, params);
-		if (retval != ERROR_OK)
-			return retval;
-		else {
-			uint32_t a = target_buffer_get_u32(target, params+0);
-			/* tell the remote we have no idea */
-			memset(params, 0, 4*4);
-			retval = target_write_memory(target, a, 4, 4, params);
-			if (retval != ERROR_OK)
-				return retval;
-			arm->semihosting_result = 0;
-		}
-		break;
-
-	case 0x18:	/* angel_SWIreason_ReportException */
-		switch (r1) {
-		case 0x20026:	/* ADP_Stopped_ApplicationExit */
-			fprintf(stderr, "semihosting: *** application exited ***\n");
-			break;
-		case 0x20000:	/* ADP_Stopped_BranchThroughZero */
-		case 0x20001:	/* ADP_Stopped_UndefinedInstr */
-		case 0x20002:	/* ADP_Stopped_SoftwareInterrupt */
-		case 0x20003:	/* ADP_Stopped_PrefetchAbort */
-		case 0x20004:	/* ADP_Stopped_DataAbort */
-		case 0x20005:	/* ADP_Stopped_AddressException */
-		case 0x20006:	/* ADP_Stopped_IRQ */
-		case 0x20007:	/* ADP_Stopped_FIQ */
-		case 0x20020:	/* ADP_Stopped_BreakPoint */
-		case 0x20021:	/* ADP_Stopped_WatchPoint */
-		case 0x20022:	/* ADP_Stopped_StepComplete */
-		case 0x20023:	/* ADP_Stopped_RunTimeErrorUnknown */
-		case 0x20024:	/* ADP_Stopped_InternalError */
-		case 0x20025:	/* ADP_Stopped_UserInterruption */
-		case 0x20027:	/* ADP_Stopped_StackOverflow */
-		case 0x20028:	/* ADP_Stopped_DivisionByZero */
-		case 0x20029:	/* ADP_Stopped_OSSpecific */
-		default:
-			fprintf(stderr, "semihosting: exception %#x\n",
-					(unsigned) r1);
-		}
-		return target_call_event_callbacks(target, TARGET_EVENT_HALTED);
-
-	case 0x12:	/* SYS_SYSTEM */
-		/* Provide SYS_SYSTEM functionality.  Uses the
-		 * libc system command, there may be a reason *NOT*
-		 * to use this, but as I can't think of one, I
-		 * implemented it this way.
-		 */
-		retval = target_read_memory(target, r1, 4, 2, params);
-		if (retval != ERROR_OK)
-			return retval;
-		else {
-			uint32_t len = target_buffer_get_u32(target, params+4);
-			uint32_t c_ptr = target_buffer_get_u32(target, params);
-			if (arm->is_semihosting_fileio) {
-				arm->semihosting_hit_fileio = true;
-				fileio_info->identifier = "system";
-				fileio_info->param_1 = c_ptr;
-				fileio_info->param_2 = len;
-			} else {
-				uint8_t cmd[256];
-				if (len > 255) {
-					arm->semihosting_result = -1;
-					arm->semihosting_errno = EINVAL;
-				} else {
-					memset(cmd, 0x0, 256);
-					retval = target_read_memory(target, c_ptr, 1, len, cmd);
-					if (retval != ERROR_OK)
-						return retval;
-					else
-						arm->semihosting_result = system((const char *)cmd);
-				}
-			}
-		}
-		break;
-	case 0x0d:	/* SYS_TMPNAM */
-	case 0x10:	/* SYS_CLOCK */
-	case 0x17:	/* angel_SWIreason_EnterSVC */
-	case 0x30:	/* SYS_ELAPSED */
-	case 0x31:	/* SYS_TICKFREQ */
-	default:
-		fprintf(stderr, "semihosting: unsupported call %#x\n",
-				(unsigned) r0);
-		arm->semihosting_result = -1;
-		arm->semihosting_errno = ENOTSUP;
-	}
-
-	return ERROR_OK;
-}
-
-static int get_gdb_fileio_info(struct target *target, struct gdb_fileio_info *fileio_info)
-{
-	struct arm *arm = target_to_arm(target);
-
-	/* To avoid uneccessary duplication, semihosting prepares the
-	 * fileio_info structure out-of-band when the target halts. See
-	 * do_semihosting for more detail.
-	 */
-	if (!arm->is_semihosting_fileio || !arm->semihosting_hit_fileio)
-		return ERROR_FAIL;
-
-	return ERROR_OK;
-}
-
-static int gdb_fileio_end(struct target *target, int result, int fileio_errno, bool ctrl_c)
-{
-	struct arm *arm = target_to_arm(target);
-	struct gdb_fileio_info *fileio_info = target->fileio_info;
-
-	/* clear pending status */
-	arm->semihosting_hit_fileio = false;
-
-	arm->semihosting_result = result;
-	arm->semihosting_errno = fileio_errno;
-
-	/* Some fileio results do not match up with what the semihosting
-	 * operation expects; for these operations, we munge the results
-	 * below:
-	 */
-	switch (arm->semihosting_op) {
-	case 0x05:	/* SYS_WRITE */
-		if (result < 0)
-			arm->semihosting_result = fileio_info->param_3;
-		else
-			arm->semihosting_result = 0;
-		break;
-
-	case 0x06:	/* SYS_READ */
-		if (result == (int)fileio_info->param_3)
-			arm->semihosting_result = 0;
-		if (result <= 0)
-			arm->semihosting_result = fileio_info->param_3;
-		break;
-
-	case 0x0a:	/* SYS_SEEK */
-		if (result > 0)
-			arm->semihosting_result = 0;
-		break;
-	}
-
-	return post_result(target);
-}
-
 /**
  * Initialize ARM semihosting support.
  *
@@ -630,14 +144,9 @@ static int gdb_fileio_end(struct target *target, int result, int fileio_errno, b
  */
 int arm_semihosting_init(struct target *target)
 {
-	target->fileio_info = malloc(sizeof(*target->fileio_info));
-	if (target->fileio_info == NULL) {
-		LOG_ERROR("out of memory");
-		return ERROR_FAIL;
-	}
-
-	target->type->get_gdb_fileio_info = get_gdb_fileio_info;
-	target->type->gdb_fileio_end = gdb_fileio_end;
+	struct arm *arm = target_to_arm(target);
+	assert(arm->setup_semihosting);
+	semihosting_common_init(target, arm->setup_semihosting, post_result);
 
 	return ERROR_OK;
 }
@@ -662,7 +171,11 @@ int arm_semihosting(struct target *target, int *retval)
 	uint32_t pc, lr, spsr;
 	struct reg *r;
 
-	if (!arm->is_semihosting)
+	struct semihosting *semihosting = target->semihosting;
+	if (!semihosting)
+		return 0;
+
+	if (!semihosting->is_active)
 		return 0;
 
 	if (is_arm7_9(target_to_arm7_9(target)) ||
@@ -758,6 +271,24 @@ int arm_semihosting(struct target *target, int *retval)
 		/* bkpt 0xAB */
 		if (insn != 0xBEAB)
 			return 0;
+	} else if (is_armv8(target_to_armv8(target))) {
+		if (target->debug_reason != DBG_REASON_BREAKPOINT)
+			return 0;
+
+		if (arm->core_state == ARM_STATE_AARCH64) {
+			uint32_t insn = 0;
+			r = arm->pc;
+			uint64_t pc64 = buf_get_u64(r->value, 0, 64);
+			*retval = target_read_u32(target, pc64, &insn);
+
+			if (*retval != ERROR_OK)
+				return 1;
+
+			/* bkpt 0xAB */
+			if (insn != 0xD45E0000)
+				return 0;
+		} else
+			return 1;
 	} else {
 		LOG_ERROR("Unsupported semi-hosting Target");
 		return 0;
@@ -766,32 +297,38 @@ int arm_semihosting(struct target *target, int *retval)
 	/* Perform semihosting if we are not waiting on a fileio
 	 * operation to complete.
 	 */
-	if (!arm->semihosting_hit_fileio) {
-		*retval = do_semihosting(target);
-		if (*retval != ERROR_OK) {
-			LOG_ERROR("Failed semihosting operation");
+	if (!semihosting->hit_fileio) {
+		if (is_armv8(target_to_armv8(target)) &&
+				arm->core_state == ARM_STATE_AARCH64) {
+			/* Read op and param from register x0 and x1 respectively. */
+			semihosting->op = buf_get_u64(arm->core_cache->reg_list[0].value, 0, 64);
+			semihosting->param = buf_get_u64(arm->core_cache->reg_list[1].value, 0, 64);
+			semihosting->word_size_bytes = 8;
+		} else {
+			/* Read op and param from register r0 and r1 respectively. */
+			semihosting->op = buf_get_u32(arm->core_cache->reg_list[0].value, 0, 32);
+			semihosting->param = buf_get_u32(arm->core_cache->reg_list[1].value, 0, 32);
+			semihosting->word_size_bytes = 4;
+		}
+
+		/* Check for ARM operation numbers. */
+		if (0 <= semihosting->op && semihosting->op <= 0x31) {
+			*retval = semihosting_common(target);
+			if (*retval != ERROR_OK) {
+				LOG_ERROR("Failed semihosting operation");
+				return 0;
+			}
+		} else {
+			/* Unknown operation number, not a semihosting call. */
 			return 0;
 		}
 	}
 
-	/* Post result to target if we are not waiting on a fileio
+	/* Resume if target it is resumable and we are not waiting on a fileio
 	 * operation to complete:
 	 */
-	if (!arm->semihosting_hit_fileio) {
-		*retval = post_result(target);
-		if (*retval != ERROR_OK) {
-			LOG_ERROR("Failed to post semihosting result");
-			return 0;
-		}
-
-		*retval = target_resume(target, 1, 0, 0, 0);
-		if (*retval != ERROR_OK) {
-			LOG_ERROR("Failed to resume target");
-			return 0;
-		}
-
-		return 1;
-	}
+	if (semihosting->is_resumable && !semihosting->hit_fileio)
+		return arm_semihosting_resume(target, retval);
 
 	return 0;
 }