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 f34082da009a..b6ed34de14e1 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);
         }
 }