File 0006-librtas-Use-dev-papr-indices-when-available-for-get-.patch of Package librtas
From ba73b7e26a517396bc0b053e1e3dab658cbde890 Mon Sep 17 00:00:00 2001
From: Haren Myneni <haren@linux.ibm.com>
Date: Sun, 9 Mar 2025 16:29:12 -0700
Subject: [PATCH 6/9] librtas: Use /dev/papr-indices when available for
get-dynamic-sensor-state
The current rtas_get_dynamic_sensor() allocates RTAS work area
and invokes sys_rtas() in the user space. But this interface will
not work under system lockdown due to restricted access to /dev/mem.
This patch add changes to use new kernel interface provided by
/dev/papr-indices entry with PAPR_DYNAMIC_SENSOR_IOC_GET ioctl.
The new state of sensor token will be returned from the user
passed papr_indices_io_block to the ioctl.
If /dev/papr-indices entry is available, the new kernel interface
is used with the following programming model:
fd = open("/dev/papr-indices", O_RDWR);
copy location-code to
papr_indices_io_block.dynamic_param.location_code_str
papr_indices_io_block.dynamic_param.token = token-val;
ret = ioctl(fd, PAPR_DYNAMIC_SENSOR_IOC_GET,
papr_indices_io_block);
state = papr_indices_io_block.dynamic_param.state
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
---
librtas_src/indices.c | 90 ++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 89 insertions(+), 1 deletion(-)
diff --git a/librtas_src/indices.c b/librtas_src/indices.c
index 67744c9..27d537c 100644
--- a/librtas_src/indices.c
+++ b/librtas_src/indices.c
@@ -34,7 +34,7 @@ static const char indices_devpath[] = "/dev/papr-indices";
* @param state reference to state variable
* @return 0 on success, !0 otherwise
*/
-int rtas_get_dynamic_sensor(int sensor, void *loc_code, int *state)
+int get_dynamic_sensor_fallback(int sensor, void *loc_code, int *state)
{
uint32_t loc_pa = 0;
void *locbuf;
@@ -217,6 +217,85 @@ static int get_indices_chardev(int is_sensor, int type, char *workarea,
return rtas_status;
}
+/*
+ * Only to be used when converting an actual error from a syscall.
+ */
+static int chardev_backconvert_errno(int saved_errno)
+{
+ const struct {
+ int linux_errno;
+ int rtas_status;
+ } map[] = {
+#define errno_to_status(e, s) { .linux_errno = (e), .rtas_status = (s), }
+ errno_to_status(EINVAL, -9999),
+ errno_to_status(EPERM, -9002),
+ errno_to_status(EOPNOTSUPP, -3),
+ errno_to_status(EIO, -1),
+ errno_to_status(EFAULT, -1),
+#undef errno_to_status
+ };
+
+ for (size_t i = 0; i < sizeof(map) / sizeof(map[0]); ++i)
+ if (map[i].linux_errno == saved_errno)
+ return map[i].rtas_status;
+ return -1;
+}
+
+static int dynamic_common_io_setup(unsigned long ioctalval,
+ void *loc_code,
+ struct papr_indices_io_block *buf)
+{
+ size_t length;
+ char *loc_str;
+ int fd, ret = -EINVAL;
+
+ fd = open(indices_devpath, O_RDWR);
+ if (fd < 0) {
+ /*
+ * Should not be here. May be /dev/papr-indices removed
+ */
+ return -1;
+ }
+
+ length = be32toh(*(uint32_t *)loc_code);
+
+ if (length < 1) {
+ dbg("Invalid length(%lu) of location code string\n", length);
+ goto out;
+ }
+
+ loc_str = (char *)((char *)loc_code + sizeof(uint32_t));
+ if (strlen(loc_str) != (length - 1)) {
+ dbg("location code string length is not matched with the passed length(%lu)\n", length);
+ goto out;
+ }
+
+ memcpy(&buf->dynamic_param.location_code_str, loc_str, length);
+
+ ret = ioctl(fd, ioctalval, buf);
+ if (ret != 0)
+ ret = chardev_backconvert_errno(errno);
+out:
+ close(fd);
+ return ret;
+}
+
+static int get_dynamic_sensor_chardev(int sensor, void *loc_code, int *state)
+{
+ struct papr_indices_io_block buf = {};
+ int ret;
+
+ buf.dynamic_param.token = sensor;
+ ret = dynamic_common_io_setup(PAPR_DYNAMIC_SENSOR_IOC_GET,
+ loc_code, &buf);
+ if (ret != 0)
+ return ret;
+
+ *state = buf.dynamic_param.state;
+
+ return 0;
+}
+
static bool indices_can_use_chardev(void)
{
struct stat statbuf;
@@ -235,6 +314,7 @@ static bool indices_can_use_chardev(void)
static int (*get_indices_fn)(int is_sensor, int type, char *workarea,
size_t size, int start, int *next);
+static int (*get_dynamic_sensor_fn)(int sensor, void *loc_code, int *state);
static void indices_fn_setup(void)
{
@@ -242,6 +322,8 @@ static void indices_fn_setup(void)
get_indices_fn = use_chardev ?
get_indices_chardev : get_indices_fallback;
+ get_dynamic_sensor_fn = use_chardev ?
+ get_dynamic_sensor_chardev : get_dynamic_sensor_fallback;
}
static pthread_once_t indices_fn_setup_once = PTHREAD_ONCE_INIT;
@@ -253,3 +335,9 @@ int rtas_get_indices(int is_sensor, int type, char *workarea, size_t size,
return get_indices_fn(is_sensor, type, workarea, size,
start, next);
}
+
+int rtas_get_dynamic_sensor(int sensor, void *loc_code, int *state)
+{
+ pthread_once(&indices_fn_setup_once, indices_fn_setup);
+ return get_dynamic_sensor_fn(sensor, loc_code, state);
+}
--
2.47.1
