From f13ae30e1397e3bfb38feb3b6e889af5d021f13d Mon Sep 17 00:00:00 2001
From: Alex Chiang <achiang@hp.com>
Date: Thu, 8 May 2008 14:03:23 -0600
Subject: [PATCH] [IA64] allow user to force_pal_cache_flush
The sequence executed in check_sal_cache_flush:
- pend a timer interrupt
- call SAL_CACHE_FLUSH
- see if interrupt is still pending
can hang HP machines with buggy SAL_CACHE_FLUSH implementations.
Provide a kernel command-line argument to allow users skip this
check if desired. Using this parameter will force ia64_sal_cache_flush
to call ia64_pal_cache_flush() instead of SAL_CACHE_FLUSH.
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
---
Documentation/kernel-parameters.txt | 6 ++++++
arch/ia64/kernel/sal.c | 11 +++++++++++
2 files changed, 17 insertions(+)
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index cdd5b934f43ea..654d630f67514 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -689,6 +689,12 @@ and is between 256 and 4096 characters. It is defined in the file
floppy= [HW]
See Documentation/floppy.txt.
+ force_pal_cache_flush
+ [IA-64] Avoid check_sal_cache_flush which may hang on
+ buggy SAL_CACHE_FLUSH implementations. Using this
+ parameter will force ia64_sal_cache_flush to call
+ ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
+
gamecon.map[2|3]=
[HW,JOY] Multisystem joystick and NES/SNES/PSX pad
support via parallel port (up to 5 devices per port)
diff --git a/arch/ia64/kernel/sal.c b/arch/ia64/kernel/sal.c
index a3022dc48ef84..7e0259709c041 100644
--- a/arch/ia64/kernel/sal.c
+++ b/arch/ia64/kernel/sal.c
@@ -229,6 +229,14 @@ static void __init sal_desc_ap_wakeup(void *p) { }
*/
static int sal_cache_flush_drops_interrupts;
+static int __init
+force_pal_cache_flush(char *str)
+{
+ sal_cache_flush_drops_interrupts = 1;
+ return 0;
+}
+early_param("force_pal_cache_flush", force_pal_cache_flush);
+
void __init
check_sal_cache_flush (void)
{
@@ -237,6 +245,9 @@ check_sal_cache_flush (void)
u64 vector, cache_type = 3;
struct ia64_sal_retval isrv;
+ if (sal_cache_flush_drops_interrupts)
+ return;
+
cpu = get_cpu();
local_irq_save(flags);
--
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