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-rw-r--r--arch/powerpc/platforms/pseries/hvconsole.c2
-rw-r--r--drivers/tty/hvc/hvc_vio.c16
2 files changed, 16 insertions, 2 deletions
diff --git a/arch/powerpc/platforms/pseries/hvconsole.c b/arch/powerpc/platforms/pseries/hvconsole.c
index 74da18de853a..73ec15cd2708 100644
--- a/arch/powerpc/platforms/pseries/hvconsole.c
+++ b/arch/powerpc/platforms/pseries/hvconsole.c
@@ -62,7 +62,7 @@ EXPORT_SYMBOL(hvc_get_chars);
* @vtermno: The vtermno or unit_address of the adapter from which the data
* originated.
* @buf: The character buffer that contains the character data to send to
- * firmware.
+ * firmware. Must be at least 16 bytes, even if count is less than 16.
* @count: Send this number of characters.
*/
int hvc_put_chars(uint32_t vtermno, const char *buf, int count)
diff --git a/drivers/tty/hvc/hvc_vio.c b/drivers/tty/hvc/hvc_vio.c
index 6de6d4a1a221..7af54d6ed5b8 100644
--- a/drivers/tty/hvc/hvc_vio.c
+++ b/drivers/tty/hvc/hvc_vio.c
@@ -107,6 +107,14 @@ static int hvterm_raw_get_chars(uint32_t vtermno, char *buf, int count)
return got;
}
+/**
+ * hvterm_raw_put_chars: send characters to firmware for given vterm adapter
+ * @vtermno: The virtual terminal number.
+ * @buf: The characters to send. Because of the underlying hypercall in
+ * hvc_put_chars(), this buffer must be at least 16 bytes long, even if
+ * you are sending fewer chars.
+ * @count: number of chars to send.
+ */
static int hvterm_raw_put_chars(uint32_t vtermno, const char *buf, int count)
{
struct hvterm_priv *pv = hvterm_privs[vtermno];
@@ -219,6 +227,7 @@ static const struct hv_ops hvterm_hvsi_ops = {
static void udbg_hvc_putc(char c)
{
int count = -1;
+ unsigned char bounce_buffer[16];
if (!hvterm_privs[0])
return;
@@ -229,7 +238,12 @@ static void udbg_hvc_putc(char c)
do {
switch(hvterm_privs[0]->proto) {
case HV_PROTOCOL_RAW:
- count = hvterm_raw_put_chars(0, &c, 1);
+ /*
+ * hvterm_raw_put_chars requires at least a 16-byte
+ * buffer, so go via the bounce buffer
+ */
+ bounce_buffer[0] = c;
+ count = hvterm_raw_put_chars(0, bounce_buffer, 1);
break;
case HV_PROTOCOL_HVSI:
count = hvterm_hvsi_put_chars(0, &c, 1);