Here is the detailed description for memrchr:
void *memrchr(const void *s, int c, size_t n);
The memrchr() function is like the memchr() function, except
that it searches backward from the end of the n bytes pointed
to by s instead of forward from the beginning.
The memrchr() functions return a pointer to the matching byte
or NULL if the character does not occur in the given memory
area.
Signed-off-by: Xiang Xiao <[email protected]>
---
include/linux/string.h | 1 +
lib/string.c | 21 +++++++++++++++++++++
2 files changed, 22 insertions(+)
diff --git a/include/linux/string.h b/include/linux/string.h
index 7927b87..f380f4b 100644
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -167,6 +167,7 @@ static inline void memcpy_flushcache(void *dst, const void *src, size_t cnt)
memcpy(dst, src, cnt);
}
#endif
+void *memrchr(const void *s, int c, size_t n);
void *memchr_inv(const void *s, int c, size_t n);
char *strreplace(char *s, char old, char new);
diff --git a/lib/string.c b/lib/string.c
index 38e4ca0..92914f6 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -964,6 +964,27 @@ void *memchr(const void *s, int c, size_t n)
EXPORT_SYMBOL(memchr);
#endif
+/**
+ * memrchr - Find a character in an area of memory.
+ * @s: The memory area
+ * @c: The byte to search for
+ * @n: The size of the area.
+ *
+ * returns the address of the last occurrence of @c, or %NULL
+ * if @c is not found
+ */
+void *memrchr(const void *s, int c, size_t n)
+{
+ const unsigned char *p = s + n;
+
+ while (n-- != 0) {
+ if ((unsigned char)c == *--p)
+ return (void *)p;
+ }
+ return NULL;
+}
+EXPORT_SYMBOL(memrchr);
+
static void *check_bytes8(const u8 *start, u8 value, unsigned int bytes)
{
while (bytes) {
--
2.7.4
From: Guiding Li <[email protected]>
This driver allows the remote processor redirect the output of
syslog/printf into the kernel log, which is very useful to see
what happen in the remote side.
Signed-off-by: Guiding Li <[email protected]>
---
drivers/rpmsg/Kconfig | 12 ++++
drivers/rpmsg/Makefile | 1 +
drivers/rpmsg/rpmsg_syslog.c | 163 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 176 insertions(+)
create mode 100644 drivers/rpmsg/rpmsg_syslog.c
diff --git a/drivers/rpmsg/Kconfig b/drivers/rpmsg/Kconfig
index d0322b4..d701614 100644
--- a/drivers/rpmsg/Kconfig
+++ b/drivers/rpmsg/Kconfig
@@ -15,6 +15,18 @@ config RPMSG_CHAR
in /dev. They make it possible for user-space programs to send and
receive rpmsg packets.
+config RPMSG_SYSLOG
+ tristate "RPMSG syslog redirection"
+ depends on RPMSG
+ help
+ Say Y here to redirect the syslog/printf from remote processor into
+ the kernel log which is very useful to see what happen in the remote
+ side.
+
+ If the remote processor hang during bootup or panic at the runtime,
+ We can even cat /sys/kernel/debug/remoteproc/remoteprocX/trace0 to
+ get the last log which doesn't output yet.
+
config RPMSG_QCOM_GLINK_NATIVE
tristate
select RPMSG
diff --git a/drivers/rpmsg/Makefile b/drivers/rpmsg/Makefile
index 9aa8595..bfd22df 100644
--- a/drivers/rpmsg/Makefile
+++ b/drivers/rpmsg/Makefile
@@ -1,6 +1,7 @@
# SPDX-License-Identifier: GPL-2.0
obj-$(CONFIG_RPMSG) += rpmsg_core.o
obj-$(CONFIG_RPMSG_CHAR) += rpmsg_char.o
+obj-$(CONFIG_RPMSG_SYSLOG) += rpmsg_syslog.o
obj-$(CONFIG_RPMSG_QCOM_GLINK_RPM) += qcom_glink_rpm.o
obj-$(CONFIG_RPMSG_QCOM_GLINK_NATIVE) += qcom_glink_native.o
obj-$(CONFIG_RPMSG_QCOM_GLINK_SMEM) += qcom_glink_smem.o
diff --git a/drivers/rpmsg/rpmsg_syslog.c b/drivers/rpmsg/rpmsg_syslog.c
new file mode 100644
index 0000000..b7a0d27
--- /dev/null
+++ b/drivers/rpmsg/rpmsg_syslog.c
@@ -0,0 +1,163 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2017 Pinecone Inc.
+ *
+ * redirect syslog/printf from remote to the kernel.
+ */
+
+#include <linux/module.h>
+#include <linux/rpmsg.h>
+#include <linux/slab.h>
+
+#define RPMSG_SYSLOG_TRANSFER 0
+#define RPMSG_SYSLOG_TRANSFER_DONE 1
+#define RPMSG_SYSLOG_SUSPEND 2
+#define RPMSG_SYSLOG_RESUME 3
+
+struct rpmsg_syslog_header {
+ u32 command;
+ s32 result;
+} __packed;
+
+struct rpmsg_syslog_transfer {
+ struct rpmsg_syslog_header header;
+ u32 count;
+ char data[0];
+} __packed;
+
+#define rpmsg_syslog_suspend rpmsg_syslog_header
+#define rpmsg_syslog_resume rpmsg_syslog_header
+#define rpmsg_syslog_transfer_done rpmsg_syslog_header
+
+struct rpmsg_syslog {
+ char *buf;
+ unsigned int next;
+ unsigned int size;
+};
+
+static int rpmsg_syslog_callback(struct rpmsg_device *rpdev,
+ void *data, int len, void *priv_, u32 src)
+{
+ struct rpmsg_syslog *priv = dev_get_drvdata(&rpdev->dev);
+ struct rpmsg_syslog_transfer *msg = data;
+ struct rpmsg_syslog_transfer_done done;
+ unsigned int copied = msg->count;
+ unsigned int printed = 0;
+ const char *nl;
+
+ if (msg->header.command != RPMSG_SYSLOG_TRANSFER)
+ return -EINVAL;
+
+ /* output the message before '\n' to the kernel log */
+ nl = memrchr(msg->data, '\n', msg->count);
+ if (nl) {
+ printed = nl + 1 - msg->data;
+ copied = msg->count - printed;
+
+ if (priv->next) {
+ pr_info("%.*s%.*s", priv->next,
+ priv->buf, printed, msg->data);
+ priv->next = 0;
+ } else {
+ pr_info("%.*s", printed, msg->data);
+ }
+ }
+
+ /* append the message after '\n' to the buffer */
+ if (copied != 0) {
+ unsigned int newsize = priv->next + copied;
+
+ if (newsize > priv->size) {
+ char *newbuf;
+
+ newbuf = krealloc(priv->buf, newsize, GFP_KERNEL);
+ if (newbuf) {
+ priv->buf = newbuf;
+ priv->size = newsize;
+ } else {
+ copied = priv->size - priv->next;
+ }
+ }
+
+ strncpy(priv->buf + priv->next, msg->data + printed, copied);
+ priv->next += copied;
+ }
+
+ done.command = RPMSG_SYSLOG_TRANSFER_DONE;
+ done.result = printed + copied;
+ return rpmsg_send(rpdev->ept, &done, sizeof(done));
+}
+
+static int rpmsg_syslog_probe(struct rpmsg_device *rpdev)
+{
+ struct rpmsg_syslog *priv;
+
+ priv = devm_kzalloc(&rpdev->dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ dev_set_drvdata(&rpdev->dev, priv);
+ return 0;
+}
+
+static void rpmsg_syslog_remove(struct rpmsg_device *rpdev)
+{
+ struct rpmsg_syslog *priv = dev_get_drvdata(&rpdev->dev);
+
+ /* flush the buffered log if need */
+ if (priv->next)
+ pr_info("%.*s\n", priv->next, priv->buf);
+ kfree(priv->buf);
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int rpmsg_syslog_dev_suspend(struct device *dev)
+{
+ struct rpmsg_device *rpdev = dev_get_drvdata(dev);
+ struct rpmsg_syslog_suspend msg = {
+ .command = RPMSG_SYSLOG_SUSPEND,
+ };
+
+ return rpmsg_send(rpdev->ept, &msg, sizeof(msg));
+}
+
+static int rpmsg_syslog_dev_resume(struct device *dev)
+{
+ struct rpmsg_device *rpdev = dev_get_drvdata(dev);
+ struct rpmsg_syslog_resume msg = {
+ .command = RPMSG_SYSLOG_RESUME,
+ };
+
+ return rpmsg_send(rpdev->ept, &msg, sizeof(msg));
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(rpmsg_syslog_pm,
+ rpmsg_syslog_dev_suspend,
+ rpmsg_syslog_dev_resume);
+
+static const struct rpmsg_device_id rpmsg_syslog_id_table[] = {
+ { .name = "rpmsg-syslog" },
+ { },
+};
+MODULE_DEVICE_TABLE(rpmsg, rpmsg_syslog_id_table);
+
+static struct rpmsg_driver rpmsg_syslog_driver = {
+ .drv = {
+ .name = "rpmsg_syslog",
+ .owner = THIS_MODULE,
+ .pm = &rpmsg_syslog_pm,
+ },
+
+ .id_table = rpmsg_syslog_id_table,
+ .probe = rpmsg_syslog_probe,
+ .callback = rpmsg_syslog_callback,
+ .remove = rpmsg_syslog_remove,
+};
+
+module_rpmsg_driver(rpmsg_syslog_driver);
+
+MODULE_ALIAS("rpmsg:rpmsg_syslog");
+MODULE_AUTHOR("Guiding Li <[email protected]>");
+MODULE_DESCRIPTION("rpmsg syslog redirection driver");
+MODULE_LICENSE("GPL v2");
--
2.7.4
On 2/13/19 7:48 PM, Xiang Xiao wrote:
> Here is the detailed description for memrchr:
>
> void *memrchr(const void *s, int c, size_t n);
>
> The memrchr() function is like the memchr() function, except
> that it searches backward from the end of the n bytes pointed
> to by s instead of forward from the beginning.
>
> The memrchr() functions return a pointer to the matching byte
> or NULL if the character does not occur in the given memory
> area.
>
> Signed-off-by: Xiang Xiao <[email protected]>
> ---
> include/linux/string.h | 1 +
> lib/string.c | 21 +++++++++++++++++++++
> 2 files changed, 22 insertions(+)
>
> diff --git a/include/linux/string.h b/include/linux/string.h
> index 7927b87..f380f4b 100644
> --- a/include/linux/string.h
> +++ b/include/linux/string.h
> @@ -167,6 +167,7 @@ static inline void memcpy_flushcache(void *dst, const void *src, size_t cnt)
> memcpy(dst, src, cnt);
> }
> #endif
> +void *memrchr(const void *s, int c, size_t n);
> void *memchr_inv(const void *s, int c, size_t n);
> char *strreplace(char *s, char old, char new);
>
> diff --git a/lib/string.c b/lib/string.c
> index 38e4ca0..92914f6 100644
> --- a/lib/string.c
> +++ b/lib/string.c
> @@ -964,6 +964,27 @@ void *memchr(const void *s, int c, size_t n)
> EXPORT_SYMBOL(memchr);
> #endif
>
> +/**
> + * memrchr - Find a character in an area of memory.
This should say up front that this is a reverse search, from the end of
the memory area backwards.
> + * @s: The memory area
> + * @c: The byte to search for
> + * @n: The size of the area.
> + *
> + * returns the address of the last occurrence of @c, or %NULL
* Return: the address of the last occurrence of @c, or %NULL
> + * if @c is not found
> + */
> +void *memrchr(const void *s, int c, size_t n)
> +{
> + const unsigned char *p = s + n;
> +
> + while (n-- != 0) {
> + if ((unsigned char)c == *--p)
> + return (void *)p;
> + }
> + return NULL;
> +}
> +EXPORT_SYMBOL(memrchr);
> +
> static void *check_bytes8(const u8 *start, u8 value, unsigned int bytes)
> {
> while (bytes) {
>
--
~Randy
On 2/13/19 7:48 PM, Xiang Xiao wrote:
> From: Guiding Li <[email protected]>
>
> This driver allows the remote processor redirect the output of
processor to redirect
> syslog/printf into the kernel log, which is very useful to see
> what happen in the remote side.
>
> Signed-off-by: Guiding Li <[email protected]>
> ---
> drivers/rpmsg/Kconfig | 12 ++++
> drivers/rpmsg/Makefile | 1 +
> drivers/rpmsg/rpmsg_syslog.c | 163 +++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 176 insertions(+)
> create mode 100644 drivers/rpmsg/rpmsg_syslog.c
>
> diff --git a/drivers/rpmsg/Kconfig b/drivers/rpmsg/Kconfig
> index d0322b4..d701614 100644
> --- a/drivers/rpmsg/Kconfig
> +++ b/drivers/rpmsg/Kconfig
> @@ -15,6 +15,18 @@ config RPMSG_CHAR
> in /dev. They make it possible for user-space programs to send and
> receive rpmsg packets.
>
> +config RPMSG_SYSLOG
> + tristate "RPMSG syslog redirection"
> + depends on RPMSG
> + help
> + Say Y here to redirect the syslog/printf from remote processor into
> + the kernel log which is very useful to see what happen in the remote
see what happens
or see what happened
> + side.
> +
> + If the remote processor hang during bootup or panic at the runtime,
hangs during bootup or panics during runtime,
> + We can even cat /sys/kernel/debug/remoteproc/remoteprocX/trace0 to
we
> + get the last log which doesn't output yet.
get the last log which hasn't been output yet.
> +
> config RPMSG_QCOM_GLINK_NATIVE
> tristate
> select RPMSG
--
~Randy