parisc : Remove broken line wrapping handling pdc_iodc_print()

commit fbea668498e93bb38ac9226c7af9120a25957375 upstream.

Remove the broken line wrapping handling in pdc_iodc_print().
It is broken in 3 ways :
  - It doesn't keep track of the current screen position, it just
    assumes that the new buffer will be printed at the begining of the
    screen.
  - It doesn't take in account that non printable characters won't
    increase the current position on the screen.
  - And last but not least, it triggers a kernel panic if a backspace
    is the first char in the provided buffer :

 Backtrace:
  [<0000000040128ec4>] pdc_console_write+0x44/0x78
  [<0000000040128f18>] pdc_console_tty_write+0x20/0x38
  [<000000004032f1ac>] n_tty_write+0x2a4/0x550
  [<000000004032b158>] tty_write+0x1e0/0x2d8
  [<00000000401bb420>] vfs_write+0xb8/0x188
  [<00000000401bb630>] sys_write+0x68/0xb8
  [<0000000040104eb8>] syscall_exit+0x0/0x14

Most terminals handle the line wrapping just fine. I've confirmed that
it works correctly on a C8000 with both vga and serial output.

Signed-off-by: Guy Martin <gmsoft@tuxicoman.be>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/arch/parisc/kernel/firmware.c b/arch/parisc/kernel/firmware.c
index df971fa..4896ed0 100644 (file)
--- a/arch/parisc/kernel/firmware.c
+++ b/arch/parisc/kernel/firmware.c
@@ -1126,15 +1126,13 @@ int pdc_iodc_print(const unsigned char *str, unsigned count)
        unsigned int i;
        unsigned long flags;
 
-       for (i = 0; i < count && i < 79;) {
+       for (i = 0; i < count;) {
                switch(str[i]) {
                case '\n':
                        iodc_dbuf[i+0] = '\r';
                        iodc_dbuf[i+1] = '\n';
                        i += 2;
                        goto print;
-               case '\b':      /* BS */
-                       i--; /* overwrite last */
                default:
                        iodc_dbuf[i] = str[i];
                        i++;
@@ -1142,15 +1140,6 @@ int pdc_iodc_print(const 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,