[PATCH 2/6] parisc: Fix locking in pdc_iodc_print() firmware call

[Helge Deller <deller@xxxxxx>]

Utilize pdc_lock spinlock to protect parallel modifications of the
iodc_dbuf[] buffer, check length to prevent buffer overflow of
iodc_dbuf[], drop the iodc_retbuf[] buffer and fix some wrong
indentings.

Signed-off-by: Helge Deller <deller@xxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # 6.0+
---
 arch/parisc/kernel/firmware.c | 23 ++++++++++++-----------
 1 file changed, 12 insertions(+), 11 deletions(-)

diff --git a/arch/parisc/kernel/firmware.c b/arch/parisc/kernel/firmware.c
index 6a7e315bcc2e..5bccf0025fbd 100644
--- a/arch/parisc/kernel/firmware.c
+++ b/arch/parisc/kernel/firmware.c
@@ -1288,9 +1288,8 @@ void pdc_io_reset_devices(void)

 #endif /* defined(BOOTLOADER) */

-/* locked by pdc_console_lock */
-static int __attribute__((aligned(8)))   iodc_retbuf[32];
-static char __attribute__((aligned(64))) iodc_dbuf[4096];
+/* locked by pdc_lock */
+static char iodc_dbuf[4096] __page_aligned_bss;

 /**
  * pdc_iodc_print - Console print using IODC.
@@ -1307,6 +1306,9 @@ int pdc_iodc_print(const unsigned char *str, unsigned count)
 	unsigned int i;
 	unsigned long flags;

+	count = min_t(unsigned int, count, sizeof(iodc_dbuf));
+
+	spin_lock_irqsave(&pdc_lock, flags);
 	for (i = 0; i < count;) {
 		switch(str[i]) {
 		case '\n':
@@ -1322,12 +1324,11 @@ int pdc_iodc_print(const unsigned char *str, unsigned count)
 	}

 print:
-        spin_lock_irqsave(&pdc_lock, flags);
-        real32_call(PAGE0->mem_cons.iodc_io,
-                    (unsigned long)PAGE0->mem_cons.hpa, ENTRY_IO_COUT,
-                    PAGE0->mem_cons.spa, __pa(PAGE0->mem_cons.dp.layers),
-                    __pa(iodc_retbuf), 0, __pa(iodc_dbuf), i, 0);
-        spin_unlock_irqrestore(&pdc_lock, flags);
+	real32_call(PAGE0->mem_cons.iodc_io,
+		(unsigned long)PAGE0->mem_cons.hpa, ENTRY_IO_COUT,
+		PAGE0->mem_cons.spa, __pa(PAGE0->mem_cons.dp.layers),
+		__pa(pdc_result), 0, __pa(iodc_dbuf), i, 0);
+	spin_unlock_irqrestore(&pdc_lock, flags);

 	return i;
 }
@@ -1354,10 +1355,10 @@ int pdc_iodc_getc(void)
 	real32_call(PAGE0->mem_kbd.iodc_io,
 		    (unsigned long)PAGE0->mem_kbd.hpa, ENTRY_IO_CIN,
 		    PAGE0->mem_kbd.spa, __pa(PAGE0->mem_kbd.dp.layers),
-		    __pa(iodc_retbuf), 0, __pa(iodc_dbuf), 1, 0);
+		    __pa(pdc_result), 0, __pa(iodc_dbuf), 1, 0);

 	ch = *iodc_dbuf;
-	status = *iodc_retbuf;
+	status = *pdc_result;
 	spin_unlock_irqrestore(&pdc_lock, flags);

 	if (status == 0)
--
2.38.1