From b8c4d76738c091ce972e522ec36c8dce6642f6fb Mon Sep 17 00:00:00 2001
From: jah <jah@FreeBSD.org>
Date: Tue, 4 Aug 2015 19:46:13 +0000
Subject: Add two new pmap functions: vm_offset_t
 pmap_quick_enter_page(vm_page_t m) void pmap_quick_remove_page(vm_offset_t
 kva)

These will create and destroy a temporary, CPU-local KVA mapping of a specified page.

Guarantees:
--Will not sleep and will not fail.
--Safe to call under a non-sleepable lock or from an ithread

Restrictions:
--Not guaranteed to be safe to call from an interrupt filter or under a spin mutex on all platforms
--Current implementation does not guarantee more than one page of mapping space across all platforms. MI code should not make nested calls to pmap_quick_enter_page.
--MI code should not perform locking while holding onto a mapping created by pmap_quick_enter_page

The idea is to use this in busdma, for bounce buffer copies as well as virtually-indexed cache maintenance on mips and arm.

NOTE: the non-i386, non-amd64 implementations of these functions still need review and testing.

Reviewed by:	kib
Approved by:	kib (mentor)
Differential Revision:	http://reviews.freebsd.org/D3013
---
 sys/sparc64/include/pcpu.h |  3 +-
 sys/sparc64/sparc64/pmap.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 70 insertions(+), 1 deletion(-)

(limited to 'sys/sparc64')

diff --git a/sys/sparc64/include/pcpu.h b/sys/sparc64/include/pcpu.h
index dbcc59c..df43810 100644
--- a/sys/sparc64/include/pcpu.h
+++ b/sys/sparc64/include/pcpu.h
@@ -51,6 +51,7 @@ struct pmap;
 	struct	intr_request *pc_irfree;				\
 	struct	pmap *pc_pmap;						\
 	vm_offset_t pc_addr;						\
+	vm_offset_t pc_qmap_addr;					\
 	u_long	pc_tickref;						\
 	u_long	pc_tickadj;						\
 	u_long	pc_tickincrement;					\
@@ -61,7 +62,7 @@ struct pmap;
 	u_int	pc_tlb_ctx;						\
 	u_int	pc_tlb_ctx_max;						\
 	u_int	pc_tlb_ctx_min;						\
-	char	__pad[405]
+	char	__pad[397]
 
 #ifdef _KERNEL
 
diff --git a/sys/sparc64/sparc64/pmap.c b/sys/sparc64/sparc64/pmap.c
index f10678e..e0dca86 100644
--- a/sys/sparc64/sparc64/pmap.c
+++ b/sys/sparc64/sparc64/pmap.c
@@ -143,6 +143,7 @@ static int pmap_protect_tte(struct pmap *pm1, struct pmap *pm2,
     struct tte *tp, vm_offset_t va);
 static int pmap_unwire_tte(pmap_t pm, pmap_t pm2, struct tte *tp,
     vm_offset_t va);
+static void pmap_init_qpages(void);
 
 /*
  * Map the given physical page at the specified virtual address in the
@@ -680,6 +681,25 @@ pmap_bootstrap(u_int cpu_impl)
 	tlb_flush_nonlocked();
 }
 
+static void
+pmap_init_qpages(void)
+{
+	struct pcpu *pc;
+	int i;
+
+	if (dcache_color_ignore != 0)
+		return;
+
+	CPU_FOREACH(i) {
+		pc = pcpu_find(i);
+		pc->pc_qmap_addr = kva_alloc(PAGE_SIZE * DCACHE_COLORS);
+		if (pc->pc_qmap_addr == 0)
+			panic("pmap_init_qpages: unable to allocate KVA");
+	}
+}
+
+SYSINIT(qpages_init, SI_SUB_CPU, SI_ORDER_ANY, pmap_init_qpages, NULL);
+
 /*
  * Map the 4MB kernel TSB pages.
  */
@@ -1934,6 +1954,54 @@ pmap_copy_page(vm_page_t msrc, vm_page_t mdst)
 	}
 }
 
+vm_offset_t
+pmap_quick_enter_page(vm_page_t m)
+{
+	vm_paddr_t pa;
+	vm_offset_t qaddr;
+	struct tte *tp;
+
+	pa = VM_PAGE_TO_PHYS(m);
+	if (dcache_color_ignore != 0 || m->md.color == DCACHE_COLOR(pa))
+		return (TLB_PHYS_TO_DIRECT(pa));
+
+	critical_enter();
+	qaddr = PCPU_GET(qmap_addr);
+	qaddr += (PAGE_SIZE * ((DCACHE_COLORS + DCACHE_COLOR(pa) -
+	    DCACHE_COLOR(qaddr)) % DCACHE_COLORS));
+	tp = tsb_kvtotte(qaddr);
+
+	KASSERT(tp->tte_data == 0, ("pmap_quick_enter_page: PTE busy"));
+	
+	tp->tte_data = TD_V | TD_8K | TD_PA(pa) | TD_CP | TD_CV | TD_W;
+	tp->tte_vpn = TV_VPN(qaddr, TS_8K);
+
+	return (qaddr);
+}
+
+void
+pmap_quick_remove_page(vm_offset_t addr)
+{
+	vm_offset_t qaddr;
+	struct tte *tp;
+
+	if (addr >= VM_MIN_DIRECT_ADDRESS)
+		return;
+
+	tp = tsb_kvtotte(addr);
+	qaddr = PCPU_GET(qmap_addr);
+	
+	KASSERT((addr >= qaddr) && (addr < (qaddr + (PAGE_SIZE * DCACHE_COLORS))),
+	    ("pmap_quick_remove_page: invalid address"));
+	KASSERT(tp->tte_data != 0, ("pmap_quick_remove_page: PTE not in use"));
+	
+	stxa(TLB_DEMAP_VA(addr) | TLB_DEMAP_NUCLEUS | TLB_DEMAP_PAGE, ASI_DMMU_DEMAP, 0);
+	stxa(TLB_DEMAP_VA(addr) | TLB_DEMAP_NUCLEUS | TLB_DEMAP_PAGE, ASI_IMMU_DEMAP, 0);
+	flush(KERNBASE);
+	TTE_ZERO(tp);
+	critical_exit();
+}
+
 int unmapped_buf_allowed;
 
 void
-- 
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