parisc: ensure broadcast tlb purge runs single threaded

The TLB flushing functions on hppa, which causes PxTLB broadcasts on the system
bus, needs to be protected by irq-safe spinlocks to avoid irq handlers to deadlock
the kernel. The deadlocks only happened during I/O intensive loads and triggered
pretty seldom, which is why this bug went so long unnoticed.

Signed-off-by: Helge Deller <deller@gmx.de>
[edited to use spin_lock_irqsave on UP as well since we'd been locking there
 all this time anyway, --kyle]
Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>

1 files changed, 15 insertions, 8 deletions

diff --git a/arch/parisc/kernel/cache.c b/arch/parisc/kernel/cache.c
index f34082da009..b6ed34de14e 100644
--- a/arch/parisc/kernel/cache.c
+++ b/arch/parisc/kernel/cache.c
@@ -397,12 +397,13 @@ EXPORT_SYMBOL(flush_kernel_icache_range_asm);
 
 void clear_user_page_asm(void *page, unsigned long vaddr)
 {
+	unsigned long flags;
 	/* This function is implemented in assembly in pacache.S */
 	extern void __clear_user_page_asm(void *page, unsigned long vaddr);
 
-	purge_tlb_start();
+	purge_tlb_start(flags);
 	__clear_user_page_asm(page, vaddr);
-	purge_tlb_end();
+	purge_tlb_end(flags);
 }
 
 #define FLUSH_THRESHOLD 0x80000 /* 0.5MB */
@@ -443,20 +444,24 @@ extern void clear_user_page_asm(void *page, unsigned long vaddr);
 
 void clear_user_page(void *page, unsigned long vaddr, struct page *pg)
 {
+	unsigned long flags;
+
 	purge_kernel_dcache_page((unsigned long)page);
-	purge_tlb_start();
+	purge_tlb_start(flags);
 	pdtlb_kernel(page);
-	purge_tlb_end();
+	purge_tlb_end(flags);
 	clear_user_page_asm(page, vaddr);
 }
 EXPORT_SYMBOL(clear_user_page);
 
 void flush_kernel_dcache_page_addr(void *addr)
 {
+	unsigned long flags;
+
 	flush_kernel_dcache_page_asm(addr);
-	purge_tlb_start();
+	purge_tlb_start(flags);
 	pdtlb_kernel(addr);
-	purge_tlb_end();
+	purge_tlb_end(flags);
 }
 EXPORT_SYMBOL(flush_kernel_dcache_page_addr);
 
@@ -489,8 +494,10 @@ void __flush_tlb_range(unsigned long sid, unsigned long start,
 	if (npages >= 512)  /* 2MB of space: arbitrary, should be tuned */
 		flush_tlb_all();
 	else {
+		unsigned long flags;
+
 		mtsp(sid, 1);
-		purge_tlb_start();
+		purge_tlb_start(flags);
 		if (split_tlb) {
 			while (npages--) {
 				pdtlb(start);
@@ -503,7 +510,7 @@ void __flush_tlb_range(unsigned long sid, unsigned long start,
 				start += PAGE_SIZE;
 			}
 		}
-		purge_tlb_end();
+		purge_tlb_end(flags);
 	}
 }