From: David S. Miller <davem@sunset.davemloft.net>
Date: Sun, 14 Oct 2007 04:51:37 +0000 (-0700)
Subject: [SPARC64]: Use sun4v VIRQ interfaces as intended.
X-Git-Tag: v2.6.24-rc1~1325^2~6
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b80e6998120eecec00781658bc43702494117ea8;p=linux-2.6

[SPARC64]: Use sun4v VIRQ interfaces as intended.

We were simply concatenating the devhandle and devino and using that
as the cookie, which defeats the entire purpose of the VIRQ hypervisor
interfaces.

Now that we use physical addresses for the INO buckets, we can
allocate them dynamically for VIRQs and encode the cookies as
~__pa(bucket).  This allows us to test for and decode the cookie with
a simple:

	brlz	$reg1, 1f
	 xnor	$reg1, %g0, $reg2

sequence.

This works because bit 64 is never set in traditional
INO vectors, and it is also never set in a physical
address.  So xnor'ing the physical address of the bucket
always gives us a negative number, and thus a unique
condition we can test cheaply.

Inspired by ideas from Greg Onufer.

Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/arch/sparc64/kernel/irq.c b/arch/sparc64/kernel/irq.c
index 5a92851296..4e9537c967 100644
--- a/arch/sparc64/kernel/irq.c
+++ b/arch/sparc64/kernel/irq.c
@@ -643,27 +643,42 @@ unsigned int sun4v_build_irq(u32 devhandle, unsigned int devino)
 
 unsigned int sun4v_build_virq(u32 devhandle, unsigned int devino)
 {
-	unsigned long sysino, hv_err;
-	unsigned int virq;
+	struct irq_handler_data *data;
+	struct ino_bucket *bucket;
+	unsigned long hv_err, cookie;
+
+	bucket = kzalloc(sizeof(struct ino_bucket), GFP_ATOMIC);
+	if (unlikely(!bucket))
+		return 0;
+
+	bucket->virt_irq = virt_irq_alloc(__irq(bucket));
+	set_irq_chip(bucket->virt_irq, &sun4v_virq);
 
-	BUG_ON(devhandle & devino);
+	data = kzalloc(sizeof(struct irq_handler_data), GFP_ATOMIC);
+	if (unlikely(!data))
+		return 0;
 
-	sysino = devhandle | devino;
-	BUG_ON(sysino & ~(IMAP_IGN | IMAP_INO));
+	set_irq_chip_data(bucket->virt_irq, data);
 
-	hv_err = sun4v_vintr_set_cookie(devhandle, devino, sysino);
+	/* Catch accidental accesses to these things.  IMAP/ICLR handling
+	 * is done by hypervisor calls on sun4v platforms, not by direct
+	 * register accesses.
+	 */
+	data->imap = ~0UL;
+	data->iclr = ~0UL;
+
+	cookie = ~__pa(bucket);
+	hv_err = sun4v_vintr_set_cookie(devhandle, devino, cookie);
 	if (hv_err) {
 		prom_printf("IRQ: Fatal, cannot set cookie for [%x:%x] "
 			    "err=%lu\n", devhandle, devino, hv_err);
 		prom_halt();
 	}
 
-	virq = sun4v_build_common(sysino, &sun4v_virq);
-
-	virt_to_real_irq_table[virq].dev_handle = devhandle;
-	virt_to_real_irq_table[virq].dev_ino = devino;
+	virt_to_real_irq_table[bucket->virt_irq].dev_handle = devhandle;
+	virt_to_real_irq_table[bucket->virt_irq].dev_ino = devino;
 
-	return virq;
+	return bucket->virt_irq;
 }
 
 void ack_bad_irq(unsigned int virt_irq)
diff --git a/arch/sparc64/kernel/sun4v_ivec.S b/arch/sparc64/kernel/sun4v_ivec.S
index 16d3064459..e2f8e1b488 100644
--- a/arch/sparc64/kernel/sun4v_ivec.S
+++ b/arch/sparc64/kernel/sun4v_ivec.S
@@ -98,13 +98,17 @@ sun4v_dev_mondo:
 
 	TRAP_LOAD_IRQ_WORK_PA(%g1, %g4)
 
+	/* For VIRQs, cookie is encoded as ~bucket_phys_addr  */
+	brlz,pt %g3, 1f
+	 xnor	%g3, %g0, %g4
+
 	/* Get __pa(&ivector_table[IVEC]) into %g4.  */
 	sethi	%hi(ivector_table_pa), %g4
 	ldx	[%g4 + %lo(ivector_table_pa)], %g4
 	sllx	%g3, 4, %g3
 	add	%g4, %g3, %g4
 
-	ldx	[%g1], %g2
+1:	ldx	[%g1], %g2
 	stxa	%g2, [%g4] ASI_PHYS_USE_EC
 	stx	%g4, [%g1]