tools/power/acpi: Add userspace AML interface support

This patch adds a userspace tool to access Linux kernel AML debugger
interface.

Tow modes are supported by this tool:
1. Interactive: Users are able to launch a debugging shell to talk with
   in-kernel AML debugger.
   Note that it's user duty to ensure kernel runtime integrity by using
   this debugging tool:
   A. Some control methods evaluated by the users may result in kernel
      panics if those control methods shouldn't be evaluated by the OSPMs
      according to the current BIOS/OS configurations.
   B. Currently if a single stepping evaluation couldn't run to an end,
      then the synchronization primitives acquired by the evaluation may
      block normal OSPM control method evaluations.
2. Batch: Users are able to execute debugger commands in a script.
   Note that in addition to the above duties, it's user duty to ensure
   script runtime integrity by using this debugging tool in this mode:
   C. Currently only those commands that are not used for single stepping
      are suitable to be used in this mode.
   D. If the execution of the command may cause a failure that could result
      in an endless kernel execution, the execution of the script may also
      get blocked.
To exit the utility, currently "exit/quit" commands are recommended, but
ctrl-C" can also be used.

Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

3 files changed, 473 insertions, 8 deletions

diff --git a/tools/power/acpi/Makefile b/tools/power/acpi/Makefile
index e882c8320135..a8bf9081512b 100644
--- a/tools/power/acpi/Makefile
+++ b/tools/power/acpi/Makefile
@@ -10,18 +10,18 @@
 
 include ../../scripts/Makefile.include
 
-all: acpidump ec
-clean: acpidump_clean ec_clean
-install: acpidump_install ec_install
-uninstall: acpidump_uninstall ec_uninstall
+all: acpidbg acpidump ec
+clean: acpidbg_clean acpidump_clean ec_clean
+install: acpidbg_install acpidump_install ec_install
+uninstall: acpidbg_uninstall acpidump_uninstall ec_uninstall
 
-acpidump ec: FORCE
+acpidbg acpidump ec: FORCE
 	$(call descend,tools/$@,all)
-acpidump_clean ec_clean:
+acpidbg_clean acpidump_clean ec_clean:
 	$(call descend,tools/$(@:_clean=),clean)
-acpidump_install ec_install:
+acpidbg_install acpidump_install ec_install:
 	$(call descend,tools/$(@:_install=),install)
-acpidump_uninstall ec_uninstall:
+acpidbg_uninstall acpidump_uninstall ec_uninstall:
 	$(call descend,tools/$(@:_uninstall=),uninstall)
 
 .PHONY: FORCE
diff --git a/tools/power/acpi/tools/acpidbg/Makefile b/tools/power/acpi/tools/acpidbg/Makefile
new file mode 100644
index 000000000000..352df4b41ae9
--- /dev/null
+++ b/tools/power/acpi/tools/acpidbg/Makefile
@@ -0,0 +1,27 @@
+# tools/power/acpi/tools/acpidbg/Makefile - ACPI tool Makefile
+#
+# Copyright (c) 2015, Intel Corporation
+#   Author: Lv Zheng <lv.zheng@intel.com>
+#
+# 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; version 2
+# of the License.
+
+include ../../Makefile.config
+
+TOOL = acpidbg
+vpath %.c \
+	../../../../../drivers/acpi/acpica\
+	../../common\
+	../../os_specific/service_layers\
+	.
+CFLAGS += -DACPI_APPLICATION -DACPI_SINGLE_THREAD -DACPI_DEBUGGER\
+	-I.\
+	-I../../../../../drivers/acpi/acpica\
+	-I../../../../../include
+LDFLAGS += -lpthread
+TOOL_OBJS = \
+	acpidbg.o
+
+include ../../Makefile.rules
diff --git a/tools/power/acpi/tools/acpidbg/acpidbg.c b/tools/power/acpi/tools/acpidbg/acpidbg.c
new file mode 100644
index 000000000000..d070fccdba6d
--- /dev/null
+++ b/tools/power/acpi/tools/acpidbg/acpidbg.c
@@ -0,0 +1,438 @@
+/*
+ * ACPI AML interfacing userspace utility
+ *
+ * Copyright (C) 2015, Intel Corporation
+ * Authors: Lv Zheng <lv.zheng@intel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <acpi/acpi.h>
+
+/* Headers not included by include/acpi/platform/aclinux.h */
+#include <stdbool.h>
+#include <fcntl.h>
+#include <assert.h>
+#include <linux/circ_buf.h>
+
+#define ACPI_AML_FILE		"/sys/kernel/debug/acpi/acpidbg"
+#define ACPI_AML_SEC_TICK	1
+#define ACPI_AML_USEC_PEEK	200
+#define ACPI_AML_BUF_SIZE	4096
+
+#define ACPI_AML_BATCH_WRITE_CMD	0x00 /* Write command to kernel */
+#define ACPI_AML_BATCH_READ_LOG		0x01 /* Read log from kernel */
+#define ACPI_AML_BATCH_WRITE_LOG	0x02 /* Write log to console */
+
+#define ACPI_AML_LOG_START		0x00
+#define ACPI_AML_PROMPT_START		0x01
+#define ACPI_AML_PROMPT_STOP		0x02
+#define ACPI_AML_LOG_STOP		0x03
+#define ACPI_AML_PROMPT_ROLL		0x04
+
+#define ACPI_AML_INTERACTIVE	0x00
+#define ACPI_AML_BATCH		0x01
+
+#define circ_count(circ) \
+	(CIRC_CNT((circ)->head, (circ)->tail, ACPI_AML_BUF_SIZE))
+#define circ_count_to_end(circ) \
+	(CIRC_CNT_TO_END((circ)->head, (circ)->tail, ACPI_AML_BUF_SIZE))
+#define circ_space(circ) \
+	(CIRC_SPACE((circ)->head, (circ)->tail, ACPI_AML_BUF_SIZE))
+#define circ_space_to_end(circ) \
+	(CIRC_SPACE_TO_END((circ)->head, (circ)->tail, ACPI_AML_BUF_SIZE))
+
+#define acpi_aml_cmd_count()	circ_count(&acpi_aml_cmd_crc)
+#define acpi_aml_log_count()	circ_count(&acpi_aml_log_crc)
+#define acpi_aml_cmd_space()	circ_space(&acpi_aml_cmd_crc)
+#define acpi_aml_log_space()	circ_space(&acpi_aml_log_crc)
+
+#define ACPI_AML_DO(_fd, _op, _buf, _ret)				\
+	do {								\
+		_ret = acpi_aml_##_op(_fd, &acpi_aml_##_buf##_crc);	\
+		if (_ret == 0) {					\
+			fprintf(stderr,					\
+				"%s %s pipe closed.\n", #_buf, #_op);	\
+			return;						\
+		}							\
+	} while (0)
+#define ACPI_AML_BATCH_DO(_fd, _op, _buf, _ret)				\
+	do {								\
+		_ret = acpi_aml_##_op##_batch_##_buf(_fd,		\
+			 &acpi_aml_##_buf##_crc);			\
+		if (_ret == 0)						\
+			return;						\
+	} while (0)
+
+
+static char acpi_aml_cmd_buf[ACPI_AML_BUF_SIZE];
+static char acpi_aml_log_buf[ACPI_AML_BUF_SIZE];
+static struct circ_buf acpi_aml_cmd_crc = {
+	.buf = acpi_aml_cmd_buf,
+	.head = 0,
+	.tail = 0,
+};
+static struct circ_buf acpi_aml_log_crc = {
+	.buf = acpi_aml_log_buf,
+	.head = 0,
+	.tail = 0,
+};
+static const char *acpi_aml_file_path = ACPI_AML_FILE;
+static unsigned long acpi_aml_mode = ACPI_AML_INTERACTIVE;
+static bool acpi_aml_exit;
+
+static bool acpi_aml_batch_drain;
+static unsigned long acpi_aml_batch_state;
+static char acpi_aml_batch_prompt;
+static char acpi_aml_batch_roll;
+static unsigned long acpi_aml_log_state;
+static char *acpi_aml_batch_cmd = NULL;
+static char *acpi_aml_batch_pos = NULL;
+
+static int acpi_aml_set_fl(int fd, int flags)
+{
+	int ret;
+
+	ret = fcntl(fd, F_GETFL, 0);
+	if (ret < 0) {
+		perror("fcntl(F_GETFL)");
+		return ret;
+	}
+	flags |= ret;
+	ret = fcntl(fd, F_SETFL, flags);
+	if (ret < 0) {
+		perror("fcntl(F_SETFL)");
+		return ret;
+	}
+	return ret;
+}
+
+static int acpi_aml_set_fd(int fd, int maxfd, fd_set *set)
+{
+	if (fd > maxfd)
+		maxfd = fd;
+	FD_SET(fd, set);
+	return maxfd;
+}
+
+static int acpi_aml_read(int fd, struct circ_buf *crc)
+{
+	char *p;
+	int len;
+
+	p = &crc->buf[crc->head];
+	len = circ_space_to_end(crc);
+	len = read(fd, p, len);
+	if (len < 0)
+		perror("read");
+	else if (len > 0)
+		crc->head = (crc->head + len) & (ACPI_AML_BUF_SIZE - 1);
+	return len;
+}
+
+static int acpi_aml_read_batch_cmd(int unused, struct circ_buf *crc)
+{
+	char *p;
+	int len;
+	int remained = strlen(acpi_aml_batch_pos);
+
+	p = &crc->buf[crc->head];
+	len = circ_space_to_end(crc);
+	if (len > remained) {
+		memcpy(p, acpi_aml_batch_pos, remained);
+		acpi_aml_batch_pos += remained;
+		len = remained;
+	} else {
+		memcpy(p, acpi_aml_batch_pos, len);
+		acpi_aml_batch_pos += len;
+	}
+	if (len > 0)
+		crc->head = (crc->head + len) & (ACPI_AML_BUF_SIZE - 1);
+	return len;
+}
+
+static int acpi_aml_read_batch_log(int fd, struct circ_buf *crc)
+{
+	char *p;
+	int len;
+	int ret = 0;
+
+	p = &crc->buf[crc->head];
+	len = circ_space_to_end(crc);
+	while (ret < len && acpi_aml_log_state != ACPI_AML_LOG_STOP) {
+		if (acpi_aml_log_state == ACPI_AML_PROMPT_ROLL) {
+			*p = acpi_aml_batch_roll;
+			len = 1;
+			crc->head = (crc->head + 1) & (ACPI_AML_BUF_SIZE - 1);
+			ret += 1;
+			acpi_aml_log_state = ACPI_AML_LOG_START;
+		} else {
+			len = read(fd, p, 1);
+			if (len <= 0) {
+				if (len < 0)
+					perror("read");
+				ret = len;
+				break;
+			}
+		}
+		switch (acpi_aml_log_state) {
+		case ACPI_AML_LOG_START:
+			if (*p == '\n')
+				acpi_aml_log_state = ACPI_AML_PROMPT_START;
+			crc->head = (crc->head + 1) & (ACPI_AML_BUF_SIZE - 1);
+			ret += 1;
+			break;
+		case ACPI_AML_PROMPT_START:
+			if (*p == ACPI_DEBUGGER_COMMAND_PROMPT ||
+			    *p == ACPI_DEBUGGER_EXECUTE_PROMPT) {
+				acpi_aml_batch_prompt = *p;
+				acpi_aml_log_state = ACPI_AML_PROMPT_STOP;
+			} else {
+				if (*p != '\n')
+					acpi_aml_log_state = ACPI_AML_LOG_START;
+				crc->head = (crc->head + 1) & (ACPI_AML_BUF_SIZE - 1);
+				ret += 1;
+			}
+			break;
+		case ACPI_AML_PROMPT_STOP:
+			if (*p == ' ') {
+				acpi_aml_log_state = ACPI_AML_LOG_STOP;
+				acpi_aml_exit = true;
+			} else {
+				/* Roll back */
+				acpi_aml_log_state = ACPI_AML_PROMPT_ROLL;
+				acpi_aml_batch_roll = *p;
+				*p = acpi_aml_batch_prompt;
+				crc->head = (crc->head + 1) & (ACPI_AML_BUF_SIZE - 1);
+				ret += 1;
+			}
+			break;
+		default:
+			assert(0);
+			break;
+		}
+	}
+	return ret;
+}
+
+static int acpi_aml_write(int fd, struct circ_buf *crc)
+{
+	char *p;
+	int len;
+
+	p = &crc->buf[crc->tail];
+	len = circ_count_to_end(crc);
+	len = write(fd, p, len);
+	if (len < 0)
+		perror("write");
+	else if (len > 0)
+		crc->tail = (crc->tail + len) & (ACPI_AML_BUF_SIZE - 1);
+	return len;
+}
+
+static int acpi_aml_write_batch_log(int fd, struct circ_buf *crc)
+{
+	char *p;
+	int len;
+
+	p = &crc->buf[crc->tail];
+	len = circ_count_to_end(crc);
+	if (!acpi_aml_batch_drain) {
+		len = write(fd, p, len);
+		if (len < 0)
+			perror("write");
+	}
+	if (len > 0)
+		crc->tail = (crc->tail + len) & (ACPI_AML_BUF_SIZE - 1);
+	return len;
+}
+
+static int acpi_aml_write_batch_cmd(int fd, struct circ_buf *crc)
+{
+	int len;
+
+	len = acpi_aml_write(fd, crc);
+	if (circ_count_to_end(crc) == 0)
+		acpi_aml_batch_state = ACPI_AML_BATCH_READ_LOG;
+	return len;
+}
+
+static void acpi_aml_loop(int fd)
+{
+	fd_set rfds;
+	fd_set wfds;
+	struct timeval tv;
+	int ret;
+	int maxfd = 0;
+
+	if (acpi_aml_mode == ACPI_AML_BATCH) {
+		acpi_aml_log_state = ACPI_AML_LOG_START;
+		acpi_aml_batch_pos = acpi_aml_batch_cmd;
+		if (acpi_aml_batch_drain)
+			acpi_aml_batch_state = ACPI_AML_BATCH_READ_LOG;
+		else
+			acpi_aml_batch_state = ACPI_AML_BATCH_WRITE_CMD;
+	}
+	acpi_aml_exit = false;
+	while (!acpi_aml_exit) {
+		tv.tv_sec = ACPI_AML_SEC_TICK;
+		tv.tv_usec = 0;
+		FD_ZERO(&rfds);
+		FD_ZERO(&wfds);
+
+		if (acpi_aml_cmd_space()) {
+			if (acpi_aml_mode == ACPI_AML_INTERACTIVE)
+				maxfd = acpi_aml_set_fd(STDIN_FILENO, maxfd, &rfds);
+			else if (strlen(acpi_aml_batch_pos) &&
+				 acpi_aml_batch_state == ACPI_AML_BATCH_WRITE_CMD)
+				ACPI_AML_BATCH_DO(STDIN_FILENO, read, cmd, ret);
+		}
+		if (acpi_aml_cmd_count() &&
+		    (acpi_aml_mode == ACPI_AML_INTERACTIVE ||
+		     acpi_aml_batch_state == ACPI_AML_BATCH_WRITE_CMD))
+			maxfd = acpi_aml_set_fd(fd, maxfd, &wfds);
+		if (acpi_aml_log_space() &&
+		    (acpi_aml_mode == ACPI_AML_INTERACTIVE ||
+		     acpi_aml_batch_state == ACPI_AML_BATCH_READ_LOG))
+			maxfd = acpi_aml_set_fd(fd, maxfd, &rfds);
+		if (acpi_aml_log_count())
+			maxfd = acpi_aml_set_fd(STDOUT_FILENO, maxfd, &wfds);
+
+		ret = select(maxfd+1, &rfds, &wfds, NULL, &tv);
+		if (ret < 0) {
+			perror("select");
+			break;
+		}
+		if (ret > 0) {
+			if (FD_ISSET(STDIN_FILENO, &rfds))
+				ACPI_AML_DO(STDIN_FILENO, read, cmd, ret);
+			if (FD_ISSET(fd, &wfds)) {
+				if (acpi_aml_mode == ACPI_AML_BATCH)
+					ACPI_AML_BATCH_DO(fd, write, cmd, ret);
+				else
+					ACPI_AML_DO(fd, write, cmd, ret);
+			}
+			if (FD_ISSET(fd, &rfds)) {
+				if (acpi_aml_mode == ACPI_AML_BATCH)
+					ACPI_AML_BATCH_DO(fd, read, log, ret);
+				else
+					ACPI_AML_DO(fd, read, log, ret);
+			}
+			if (FD_ISSET(STDOUT_FILENO, &wfds)) {
+				if (acpi_aml_mode == ACPI_AML_BATCH)
+					ACPI_AML_BATCH_DO(STDOUT_FILENO, write, log, ret);
+				else
+					ACPI_AML_DO(STDOUT_FILENO, write, log, ret);
+			}
+		}
+	}
+}
+
+static bool acpi_aml_readable(int fd)
+{
+	fd_set rfds;
+	struct timeval tv;
+	int ret;
+	int maxfd = 0;
+
+	tv.tv_sec = 0;
+	tv.tv_usec = ACPI_AML_USEC_PEEK;
+	FD_ZERO(&rfds);
+	maxfd = acpi_aml_set_fd(fd, maxfd, &rfds);
+	ret = select(maxfd+1, &rfds, NULL, NULL, &tv);
+	if (ret < 0)
+		perror("select");
+	if (ret > 0 && FD_ISSET(fd, &rfds))
+		return true;
+	return false;
+}
+
+/*
+ * This is a userspace IO flush implementation, replying on the prompt
+ * characters and can be turned into a flush() call after kernel implements
+ * .flush() filesystem operation.
+ */
+static void acpi_aml_flush(int fd)
+{
+	while (acpi_aml_readable(fd)) {
+		acpi_aml_batch_drain = true;
+		acpi_aml_loop(fd);
+		acpi_aml_batch_drain = false;
+	}
+}
+
+void usage(FILE *file, char *progname)
+{
+	fprintf(file, "usage: %s [-b cmd] [-f file] [-h]\n", progname);
+	fprintf(file, "\nOptions:\n");
+	fprintf(file, "  -b     Specify command to be executed in batch mode\n");
+	fprintf(file, "  -f     Specify interface file other than");
+	fprintf(file, "         /sys/kernel/debug/acpi/acpidbg\n");
+	fprintf(file, "  -h     Print this help message\n");
+}
+
+int main(int argc, char **argv)
+{
+	int fd = 0;
+	int ch;
+	int len;
+	int ret = EXIT_SUCCESS;
+
+	while ((ch = getopt(argc, argv, "b:f:h")) != -1) {
+		switch (ch) {
+		case 'b':
+			if (acpi_aml_batch_cmd) {
+				fprintf(stderr, "Already specify %s\n",
+					acpi_aml_batch_cmd);
+				ret = EXIT_FAILURE;
+				goto exit;
+			}
+			len = strlen(optarg);
+			acpi_aml_batch_cmd = calloc(len + 2, 1);
+			if (!acpi_aml_batch_cmd) {
+				perror("calloc");
+				ret = EXIT_FAILURE;
+				goto exit;
+			}
+			memcpy(acpi_aml_batch_cmd, optarg, len);
+			acpi_aml_batch_cmd[len] = '\n';
+			acpi_aml_mode = ACPI_AML_BATCH;
+			break;
+		case 'f':
+			acpi_aml_file_path = optarg;
+			break;
+		case 'h':
+			usage(stdout, argv[0]);
+			goto exit;
+			break;
+		case '?':
+		default:
+			usage(stderr, argv[0]);
+			ret = EXIT_FAILURE;
+			goto exit;
+			break;
+		}
+	}
+
+	fd = open(acpi_aml_file_path, O_RDWR | O_NONBLOCK);
+	if (fd < 0) {
+		perror("open");
+		ret = EXIT_FAILURE;
+		goto exit;
+	}
+	acpi_aml_set_fl(STDIN_FILENO, O_NONBLOCK);
+	acpi_aml_set_fl(STDOUT_FILENO, O_NONBLOCK);
+
+	if (acpi_aml_mode == ACPI_AML_BATCH)
+		acpi_aml_flush(fd);
+	acpi_aml_loop(fd);
+
+exit:
+	if (fd < 0)
+		close(fd);
+	if (acpi_aml_batch_cmd)
+		free(acpi_aml_batch_cmd);
+	return ret;
+}