Attachment 50658 Details for Bug 117197

[patch] Add boot param pdc=off to disable pdc

amd64-pdc-disable_10_0.diff (text/plain), 2.09 KB, created by Thomas Renninger on 2005-09-22 14:19:54 UTC

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Creator: Thomas Renninger

Created: 2005-09-22 14:19:54 UTC

Size: 2.09 KB

patch

obsolete

>From: okir@suse.de 
>(inverted on/off logic by trenn@suse.de)
>
>Subject: add boot option to enable advanced PDC
>References: 72919 and 117197
>
>This patch is a workaround to disable the advanced page directory cache
>on AMD64 machines via boot parameter pdc=off. Based on sample code by AMD.
>
>On some Opteron-SMP pdc leads to strange segfault ... error 4
>messages. This generally can be fixed with a BIOS update (recommended).
>If no new BIOS is available setting pdc=off should help
>
>
>--- x/arch/x86_64/kernel/setup.c.orig	2005-09-22 16:06:07.000000000 +0200
>+++ y/arch/x86_64/kernel/setup.c	2005-09-22 16:12:07.000000000 +0200
>@@ -76,6 +76,9 @@
> extern acpi_interrupt_flags	acpi_sci_flags;
> int __initdata acpi_force = 0;
> #endif
>+#ifdef CONFIG_SMP
>+static int amd_pdc_disable = 0;
>+#endif
> 
> int acpi_numa __initdata;
> 
>@@ -366,6 +369,10 @@
> 			iommu_setup(from+6); 
> 		}
> #endif
>+#ifdef  CONFIG_SMP
>+		if (!memcmp(from, "pdc=off", 6))
>+			amd_pdc_disable = 1;
>+#endif
> 
> 		if (!memcmp(from,"oops=panic", 10))
> 			panic_on_oops = 1;
>@@ -798,6 +805,20 @@
> #endif
> }
> 
>+static inline void amd_disable_advanced_pdc(void)
>+{
>+	__asm__ __volatile__ (
>+		" movl	 $0x9c5a203a,%%edi   \n" /* msr enable       */
>+		" movl	 $0xC0011023,%%ecx   \n" /* msr addr	     */
>+		" rdmsr			     \n" /* get reg val	     */
>+		" orl	 $0x00000001,%%edx   \n" /* set bit 32	     */
>+		" wrmsr			     \n" /* put it back	     */
>+		" xorl	%%edi, %%edi	     \n" /* clear msr enable */
>+		: /* no outputs */
>+		: /* no inputs, either */
>+		: "%eax","%ecx","%edx","%edi" /* clobbered regs */ );
>+}
>+
> static int __init init_amd(struct cpuinfo_x86 *c)
> {
> 	int r;
>@@ -812,6 +833,21 @@
> 	if ((level >= 0x0f48 && level < 0x0f50) || level >= 0x0f58)
> 		set_bit(X86_FEATURE_K8_C, &c->x86_capability);
> 
>+#ifdef  CONFIG_SMP
>+	if (amd_pdc_disable) {
>+		int family;
>+
>+		family = (level & 0xf00) >> 8;
>+		if (family == 0x0f)
>+			family += (level & 0xff00000) >> 20;
>+
>+		if (family == 0x0f || family == 0x10) {
>+			/* printk(KERN_INFO "Disabling advanced PDC\n"); */
>+			amd_disable_advanced_pdc();
>+		}
>+	}
>+#endif
>+
> 	r = get_model_name(c);
> 	if (!r) { 
> 		switch (c->x86) {

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Attachments on bug 117197: 50658