[PATCH 6.18.y 3/4] ACPI: TAD: Rearrange RT data validation checking

[Sasha Levin <sashal@kernel.org>]

From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>

[ Upstream commit 3329a1416c3350449081ca5daaa94802a65b2992 ]

Move RT data validation checks from acpi_tad_set_real_time() to
a separate function called acpi_tad_rt_is_invalid() and use it
also in acpi_tad_get_real_time() to validate data coming from
the platform firmware.

Also make acpi_tad_set_real_time() return -EINVAL when the RT data
passed to it is invalid (instead of -ERANGE which is somewhat
confusing) and introduce ACPI_TAD_TZ_UNSPEC to represent the
"unspecified timezone" value.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://patch.msgid.link/3409319.aeNJFYEL58@rafael.j.wysocki
Stable-dep-of: a3df8bbe0a70 ("ACPI: TAD: Add locking around AML evaluations")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/acpi/acpi_tad.c | 142 +++++++++++++++++++++++++++-------------
 include/linux/acpi.h    |   4 ++
 2 files changed, 101 insertions(+), 45 deletions(-)

diff --git a/drivers/acpi/acpi_tad.c b/drivers/acpi/acpi_tad.c
index fcebfa7d507f5..65f0a1c91d6f5 100644
--- a/drivers/acpi/acpi_tad.c
+++ b/drivers/acpi/acpi_tad.c
@@ -49,6 +49,9 @@ MODULE_AUTHOR("Rafael J. Wysocki");
 /* Special value for disabled timer or expired timer wake policy. */
 #define ACPI_TAD_WAKE_DISABLED	(~(u32)0)
 
+/* ACPI TAD RTC */
+#define ACPI_TAD_TZ_UNSPEC	2047
+
 struct acpi_tad_driver_data {
 	u32 capabilities;
 };
@@ -67,6 +70,16 @@ struct acpi_tad_rt {
 	u8 padding[3]; /* must be 0 */
 } __packed;
 
+static bool acpi_tad_rt_is_invalid(struct acpi_tad_rt *rt)
+{
+	return rt->year < 1900 || rt->year > 9999 ||
+	    rt->month < 1 || rt->month > 12 ||
+	    rt->hour > 23 || rt->minute > 59 || rt->second > 59 ||
+	    rt->tz < -1440 ||
+	    (rt->tz > 1440 && rt->tz != ACPI_TAD_TZ_UNSPEC) ||
+	    rt->daylight > 3;
+}
+
 static int acpi_tad_set_real_time(struct device *dev, struct acpi_tad_rt *rt)
 {
 	acpi_handle handle = ACPI_HANDLE(dev);
@@ -80,12 +93,8 @@ static int acpi_tad_set_real_time(struct device *dev, struct acpi_tad_rt *rt)
 	unsigned long long retval;
 	acpi_status status;
 
-	if (rt->year < 1900 || rt->year > 9999 ||
-	    rt->month < 1 || rt->month > 12 ||
-	    rt->hour > 23 || rt->minute > 59 || rt->second > 59 ||
-	    rt->tz < -1440 || (rt->tz > 1440 && rt->tz != 2047) ||
-	    rt->daylight > 3)
-		return -ERANGE;
+	if (acpi_tad_rt_is_invalid(rt))
+		return -EINVAL;
 
 	args[0].buffer.pointer = (u8 *)rt;
 	args[0].buffer.length = sizeof(*rt);
@@ -102,7 +111,7 @@ static int acpi_tad_set_real_time(struct device *dev, struct acpi_tad_rt *rt)
 	return 0;
 }
 
-static int acpi_tad_get_real_time(struct device *dev, struct acpi_tad_rt *rt)
+static int acpi_tad_evaluate_grt(struct device *dev, struct acpi_tad_rt *rt)
 {
 	acpi_handle handle = ACPI_HANDLE(dev);
 	struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER };
@@ -111,12 +120,7 @@ static int acpi_tad_get_real_time(struct device *dev, struct acpi_tad_rt *rt)
 	acpi_status status;
 	int ret = -EIO;
 
-	pm_runtime_get_sync(dev);
-
 	status = acpi_evaluate_object(handle, "_GRT", NULL, &output);
-
-	pm_runtime_put_sync(dev);
-
 	if (ACPI_FAILURE(status))
 		goto out_free;
 
@@ -139,6 +143,80 @@ static int acpi_tad_get_real_time(struct device *dev, struct acpi_tad_rt *rt)
 	return ret;
 }
 
+static int __acpi_tad_get_real_time(struct device *dev, struct acpi_tad_rt *rt)
+{
+	int ret;
+
+	ret = acpi_tad_evaluate_grt(dev, rt);
+	if (ret)
+		return ret;
+
+	if (acpi_tad_rt_is_invalid(rt))
+		return -ENODATA;
+
+	return 0;
+}
+
+static int acpi_tad_get_real_time(struct device *dev, struct acpi_tad_rt *rt)
+{
+	int ret;
+
+	pm_runtime_get_sync(dev);
+
+	ret = __acpi_tad_get_real_time(dev, rt);
+
+	pm_runtime_put_sync(dev);
+
+	return ret;
+}
+
+static int __acpi_tad_wake_set(struct device *dev, char *method, u32 timer_id,
+			       u32 value)
+{
+	acpi_handle handle = ACPI_HANDLE(dev);
+	union acpi_object args[] = {
+		{ .type = ACPI_TYPE_INTEGER, },
+		{ .type = ACPI_TYPE_INTEGER, },
+	};
+	struct acpi_object_list arg_list = {
+		.pointer = args,
+		.count = ARRAY_SIZE(args),
+	};
+	unsigned long long retval;
+	acpi_status status;
+
+	args[0].integer.value = timer_id;
+	args[1].integer.value = value;
+
+	status = acpi_evaluate_integer(handle, method, &arg_list, &retval);
+	if (ACPI_FAILURE(status) || retval)
+		return -EIO;
+
+	return 0;
+}
+
+static int __acpi_tad_wake_read(struct device *dev, char *method, u32 timer_id,
+				unsigned long long *retval)
+{
+	acpi_handle handle = ACPI_HANDLE(dev);
+	union acpi_object args[] = {
+		{ .type = ACPI_TYPE_INTEGER, },
+	};
+	struct acpi_object_list arg_list = {
+		.pointer = args,
+		.count = ARRAY_SIZE(args),
+	};
+	acpi_status status;
+
+	args[0].integer.value = timer_id;
+
+	status = acpi_evaluate_integer(handle, method, &arg_list, retval);
+	if (ACPI_FAILURE(status))
+		return -EIO;
+
+	return 0;
+}
+
 static char *acpi_tad_rt_next_field(char *s, int *val)
 {
 	char *p;
@@ -251,31 +329,15 @@ static const struct attribute_group acpi_tad_time_attr_group = {
 static int acpi_tad_wake_set(struct device *dev, char *method, u32 timer_id,
 			     u32 value)
 {
-	acpi_handle handle = ACPI_HANDLE(dev);
-	union acpi_object args[] = {
-		{ .type = ACPI_TYPE_INTEGER, },
-		{ .type = ACPI_TYPE_INTEGER, },
-	};
-	struct acpi_object_list arg_list = {
-		.pointer = args,
-		.count = ARRAY_SIZE(args),
-	};
-	unsigned long long retval;
-	acpi_status status;
-
-	args[0].integer.value = timer_id;
-	args[1].integer.value = value;
+	int ret;
 
 	pm_runtime_get_sync(dev);
 
-	status = acpi_evaluate_integer(handle, method, &arg_list, &retval);
+	ret = __acpi_tad_wake_set(dev, method, timer_id, value);
 
 	pm_runtime_put_sync(dev);
 
-	if (ACPI_FAILURE(status) || retval)
-		return -EIO;
-
-	return 0;
+	return ret;
 }
 
 static int acpi_tad_wake_write(struct device *dev, const char *buf, char *method,
@@ -301,27 +363,17 @@ static int acpi_tad_wake_write(struct device *dev, const char *buf, char *method
 static ssize_t acpi_tad_wake_read(struct device *dev, char *buf, char *method,
 				  u32 timer_id, const char *specval)
 {
-	acpi_handle handle = ACPI_HANDLE(dev);
-	union acpi_object args[] = {
-		{ .type = ACPI_TYPE_INTEGER, },
-	};
-	struct acpi_object_list arg_list = {
-		.pointer = args,
-		.count = ARRAY_SIZE(args),
-	};
 	unsigned long long retval;
-	acpi_status status;
-
-	args[0].integer.value = timer_id;
+	int ret;
 
 	pm_runtime_get_sync(dev);
 
-	status = acpi_evaluate_integer(handle, method, &arg_list, &retval);
+	ret = __acpi_tad_wake_read(dev, method, timer_id, &retval);
 
 	pm_runtime_put_sync(dev);
 
-	if (ACPI_FAILURE(status))
-		return -EIO;
+	if (ret)
+		return ret;
 
 	if ((u32)retval == ACPI_TAD_WAKE_DISABLED)
 		return sprintf(buf, "%s\n", specval);
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 165ed21de842a..8871f2edca712 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -785,7 +785,11 @@ int acpi_mrrm_max_mem_region(void);
 	{ "PNP0B02", },		\
 	{ "", }
 
+#ifdef CONFIG_X86
 extern bool cmos_rtc_platform_device_present;
+#else
+#define cmos_rtc_platform_device_present	false
+#endif
 
 #else	/* !CONFIG_ACPI */
 
-- 
2.53.0