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Date:      Wed, 21 Oct 2015 14:57:59 +0000 (UTC)
From:      Ian Lepore <ian@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r289699 - in head/sys/mips: include mips
Message-ID:  <201510211457.t9LEvx3H000101@repo.freebsd.org>
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Author: ian
Date: Wed Oct 21 14:57:59 2015
New Revision: 289699
URL: https://svnweb.freebsd.org/changeset/base/289699

Log:
  Switch from a stub to a real implementation of pmap_page_set_attr() for mips,
  and implement support for VM_MEMATTR_UNCACHEABLE.  This will be used in
  upcoming changes to support BUS_DMA_COHERENT in bus_dmamem_alloc().
  
  Reviewed by:	adrian, imp

Modified:
  head/sys/mips/include/pmap.h
  head/sys/mips/mips/pmap.c

Modified: head/sys/mips/include/pmap.h
==============================================================================
--- head/sys/mips/include/pmap.h	Wed Oct 21 13:59:00 2015	(r289698)
+++ head/sys/mips/include/pmap.h	Wed Oct 21 14:57:59 2015	(r289699)
@@ -74,6 +74,7 @@ struct md_page {
 };
 
 #define	PV_TABLE_REF		0x02	/* referenced */
+#define	PV_MEMATTR_UNCACHEABLE	0x04
 
 #define	ASID_BITS		8
 #define	ASIDGEN_BITS		(32 - ASID_BITS)
@@ -165,7 +166,6 @@ extern vm_paddr_t dump_avail[PHYS_AVAIL_
 #define	pmap_page_get_memattr(m)	VM_MEMATTR_DEFAULT
 #define	pmap_page_is_mapped(m)	(!TAILQ_EMPTY(&(m)->md.pv_list))
 #define	pmap_page_is_write_mapped(m)	(((m)->aflags & PGA_WRITEABLE) != 0)
-#define	pmap_page_set_memattr(m, ma)	(void)0
 
 void pmap_bootstrap(void);
 void *pmap_mapdev(vm_paddr_t, vm_size_t);
@@ -179,6 +179,7 @@ void pmap_kenter_temporary_free(vm_paddr
 void pmap_flush_pvcache(vm_page_t m);
 int pmap_emulate_modified(pmap_t pmap, vm_offset_t va);
 void pmap_grow_direct_page_cache(void);
+void pmap_page_set_memattr(vm_page_t, vm_memattr_t);
 
 #endif				/* _KERNEL */
 

Modified: head/sys/mips/mips/pmap.c
==============================================================================
--- head/sys/mips/mips/pmap.c	Wed Oct 21 13:59:00 2015	(r289698)
+++ head/sys/mips/mips/pmap.c	Wed Oct 21 14:57:59 2015	(r289699)
@@ -314,6 +314,15 @@ pmap_lmem_unmap(void)
 }
 #endif /* !__mips_n64 */
 
+static __inline int
+is_cacheable_page(vm_paddr_t pa, vm_page_t m)
+{
+
+	return ((m->md.pv_flags & PV_MEMATTR_UNCACHEABLE) == 0 &&
+	    is_cacheable_mem(pa));
+
+}
+
 /*
  * Page table entry lookup routines.
  */
@@ -2009,7 +2018,7 @@ pmap_enter(pmap_t pmap, vm_offset_t va, 
 		newpte |= PTE_W;
 	if (is_kernel_pmap(pmap))
 		newpte |= PTE_G;
-	if (is_cacheable_mem(pa))
+	if (is_cacheable_page(pa, m))
 		newpte |= PTE_C_CACHE;
 	else
 		newpte |= PTE_C_UNCACHED;
@@ -2280,7 +2289,7 @@ pmap_enter_quick_locked(pmap_t pmap, vm_
 	if ((m->oflags & VPO_UNMANAGED) == 0)
 		*pte |= PTE_MANAGED;
 
-	if (is_cacheable_mem(pa))
+	if (is_cacheable_page(pa, m))
 		*pte |= PTE_C_CACHE;
 	else
 		*pte |= PTE_C_UNCACHED;
@@ -2650,9 +2659,12 @@ pmap_quick_enter_page(vm_page_t m)
 
 	pa = VM_PAGE_TO_PHYS(m);
 
-	if (MIPS_DIRECT_MAPPABLE(pa))
-		return (MIPS_PHYS_TO_DIRECT(pa));
-
+	if (MIPS_DIRECT_MAPPABLE(pa)) {
+		if (m->md.pv_flags & PV_MEMATTR_UNCACHEABLE)
+			return (MIPS_PHYS_TO_DIRECT_UNCACHED(pa));
+		else
+			return (MIPS_PHYS_TO_DIRECT(pa));
+	}
 	critical_enter();
 	sysm = &sysmap_lmem[PCPU_GET(cpuid)];
 
@@ -2660,7 +2672,7 @@ pmap_quick_enter_page(vm_page_t m)
 
 	pte = pmap_pte(kernel_pmap, sysm->base);
 	*pte = TLBLO_PA_TO_PFN(pa) | PTE_D | PTE_V | PTE_G |
-	    (is_cacheable_mem(pa) ? PTE_C_CACHE : PTE_C_UNCACHED);
+	    (is_cacheable_page(pa, m) ? PTE_C_CACHE : PTE_C_UNCACHED);
 	sysm->valid1 = 1;
 
 	return (sysm->base);
@@ -3520,3 +3532,27 @@ pmap_flush_pvcache(vm_page_t m)
 		}
 	}
 }
+
+void
+pmap_page_set_memattr(vm_page_t m, vm_memattr_t ma)
+{
+
+	/*
+	 * It appears that this function can only be called before any mappings
+	 * for the page are established.  If this ever changes, this code will
+	 * need to walk the pv_list and make each of the existing mappings
+	 * uncacheable, being careful to sync caches and PTEs (and maybe
+	 * invalidate TLB?) for any current mapping it modifies.
+	 */
+	if (TAILQ_FIRST(&m->md.pv_list) != NULL)
+		panic("Can't change memattr on page with existing mappings");
+
+	/*
+	 * The only memattr we support is UNCACHEABLE, translate the (semi-)MI
+	 * representation of that into our internal flag in the page MD struct.
+	 */
+	if (ma == VM_MEMATTR_UNCACHEABLE)
+		m->md.pv_flags |= PV_MEMATTR_UNCACHEABLE;
+	else
+		m->md.pv_flags &= ~PV_MEMATTR_UNCACHEABLE;
+}

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