[PARISC] pdc_console: fix bizarre panic on boot

Commit 721fdf34167580ff98263c74cead8871d76936e6 introduced a subtle bug
by accidently removing the "static" from iodc_dbuf. This resulted in, what
appeared to be, a trap without *current set to a task. Probably the result of
a trap in real mode while calling firmware.

Also do other misc clean ups. Since the only input from firmware is non
blocking, share iodc_dbuf between input and output, and spinlock the
only callers.

Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>

3 files changed, 35 insertions, 13 deletions

diff --git a/arch/parisc/kernel/firmware.c b/arch/parisc/kernel/firmware.c
index 4ab83d56974d..7177a6cd1b7f 100644
--- a/arch/parisc/kernel/firmware.c
+++ b/arch/parisc/kernel/firmware.c
@@ -1080,6 +1080,9 @@ void pdc_io_reset_devices(void)
         spin_unlock_irqrestore(&pdc_lock, flags);
 }
 
+/* locked by pdc_console_lock */
+static int __attribute__((aligned(8)))   iodc_retbuf[32];
+static char __attribute__((aligned(64))) iodc_dbuf[4096];
 
 /**
  * pdc_iodc_print - Console print using IODC.
@@ -1091,24 +1094,20 @@ void pdc_io_reset_devices(void)
  * Since the HP console requires CR+LF to perform a 'newline', we translate
  * "\n" to "\r\n".
  */
-int pdc_iodc_print(unsigned char *str, unsigned count)
+int pdc_iodc_print(const unsigned char *str, unsigned count)
 {
-        /* XXX Should we spinlock posx usage */
         static int posx;        /* for simple TAB-Simulation... */
-        int __attribute__((aligned(8)))   iodc_retbuf[32];
-        char __attribute__((aligned(64))) iodc_dbuf[4096];
         unsigned int i;
         unsigned long flags;
 
-        memset(iodc_dbuf, 0, 4096);
-        for (i = 0; i < count && i < 2048;) {
+        for (i = 0; i < count && i < 79;) {
                 switch(str[i]) {
                 case '\n':
                         iodc_dbuf[i+0] = '\r';
                         iodc_dbuf[i+1] = '\n';
                         i += 2;
                         posx = 0;
-                        break;
+                        goto print;
                 case '\t':
                         while (posx & 7) {
                                 iodc_dbuf[i] = ' ';
@@ -1124,6 +1123,16 @@ int pdc_iodc_print(unsigned char *str, unsigned count)
                 }
         }
 
+        /* if we're at the end of line, and not already inserting a newline,
+         * insert one anyway. iodc console doesn't claim to support >79 char
+         * lines. don't account for this in the return value.
+         */
+        if (i == 79 && iodc_dbuf[i-1] != '\n') {
+                iodc_dbuf[i+0] = '\r';
+                iodc_dbuf[i+1] = '\n';
+        }
+
+print:
         spin_lock_irqsave(&pdc_lock, flags);
         real32_call(PAGE0->mem_cons.iodc_io,
                     (unsigned long)PAGE0->mem_cons.hpa, ENTRY_IO_COUT,
@@ -1142,11 +1151,9 @@ int pdc_iodc_print(unsigned char *str, unsigned count)
  */
 int pdc_iodc_getc(void)
 {
-        unsigned long flags;
-        static int __attribute__((aligned(8)))   iodc_retbuf[32];
-        static char __attribute__((aligned(64))) iodc_dbuf[4096];
         int ch;
         int status;
+        unsigned long flags;
 
         /* Bail if no console input device. */
         if (!PAGE0->mem_kbd.iodc_io)
diff --git a/arch/parisc/kernel/pdc_cons.c b/arch/parisc/kernel/pdc_cons.c
index e7afc899d717..ccb68090781e 100644
--- a/arch/parisc/kernel/pdc_cons.c
+++ b/arch/parisc/kernel/pdc_cons.c
@@ -52,15 +52,30 @@
 #include <linux/tty.h>
 #include <asm/pdc.h>            /* for iodc_call() proto and friends */
 
+static spinlock_t pdc_console_lock = SPIN_LOCK_UNLOCKED;
 
 static void pdc_console_write(struct console *co, const char *s, unsigned count)
 {
-        pdc_iodc_print(s, count);
+        int i = 0;
+        unsigned long flags;
+
+        spin_lock_irqsave(&pdc_console_lock, flags);
+        do {
+                i += pdc_iodc_print(s + i, count - i);
+        } while (i < count);
+        spin_unlock_irqrestore(&pdc_console_lock, flags);
 }
 
 int pdc_console_poll_key(struct console *co)
 {
-        return pdc_iodc_getc();
+        int c;
+        unsigned long flags;
+
+        spin_lock_irqsave(&pdc_console_lock, flags);
+        c = pdc_iodc_getc();
+        spin_unlock_irqrestore(&pdc_console_lock, flags);
+
+        return c;
 }
 
 static int pdc_console_setup(struct console *co, char *options)
diff --git a/include/asm-parisc/pdc.h b/include/asm-parisc/pdc.h
index b340c42f6bbc..9eaa794c3e4a 100644
--- a/include/asm-parisc/pdc.h
+++ b/include/asm-parisc/pdc.h
@@ -645,7 +645,7 @@ int pdc_soft_power_button(int sw_control);
 void pdc_io_reset(void);
 void pdc_io_reset_devices(void);
 int pdc_iodc_getc(void);
-int pdc_iodc_print(unsigned char *str, unsigned count);
+int pdc_iodc_print(const unsigned char *str, unsigned count);
 
 void pdc_emergency_unlock(void);
 int pdc_sti_call(unsigned long func, unsigned long flags,