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authorHelge Deller <deller@gmx.de>2009-06-16 16:51:48 -0400
committerKyle McMartin <kyle@mcmartin.ca>2009-07-02 23:34:09 -0400
commite82a3b75127188f20c7780bec580e148beb29da7 (patch)
tree8a11d55123c20b5341a95941c77eb3d35e4ef9d8
parent84be31be3727d11b2a91781306b642e801c5a379 (diff)
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>
-rw-r--r--arch/parisc/include/asm/tlbflush.h14
-rw-r--r--arch/parisc/kernel/cache.c23
-rw-r--r--arch/parisc/kernel/pci-dma.c12
3 files changed, 30 insertions, 19 deletions
diff --git a/arch/parisc/include/asm/tlbflush.h b/arch/parisc/include/asm/tlbflush.h
index 1f6fd4fc05b9..8f1a8100bf2d 100644
--- a/arch/parisc/include/asm/tlbflush.h
+++ b/arch/parisc/include/asm/tlbflush.h
@@ -12,14 +12,12 @@
12 * N class systems, only one PxTLB inter processor broadcast can be 12 * N class systems, only one PxTLB inter processor broadcast can be
13 * active at any one time on the Merced bus. This tlb purge 13 * active at any one time on the Merced bus. This tlb purge
14 * synchronisation is fairly lightweight and harmless so we activate 14 * synchronisation is fairly lightweight and harmless so we activate
15 * it on all SMP systems not just the N class. We also need to have 15 * it on all systems not just the N class.
16 * preemption disabled on uniprocessor machines, and spin_lock does that
17 * nicely.
18 */ 16 */
19extern spinlock_t pa_tlb_lock; 17extern spinlock_t pa_tlb_lock;
20 18
21#define purge_tlb_start(x) spin_lock(&pa_tlb_lock) 19#define purge_tlb_start(flags) spin_lock_irqsave(&pa_tlb_lock, flags)
22#define purge_tlb_end(x) spin_unlock(&pa_tlb_lock) 20#define purge_tlb_end(flags) spin_unlock_irqrestore(&pa_tlb_lock, flags)
23 21
24extern void flush_tlb_all(void); 22extern void flush_tlb_all(void);
25extern void flush_tlb_all_local(void *); 23extern void flush_tlb_all_local(void *);
@@ -63,14 +61,16 @@ static inline void flush_tlb_mm(struct mm_struct *mm)
63static inline void flush_tlb_page(struct vm_area_struct *vma, 61static inline void flush_tlb_page(struct vm_area_struct *vma,
64 unsigned long addr) 62 unsigned long addr)
65{ 63{
64 unsigned long flags;
65
66 /* For one page, it's not worth testing the split_tlb variable */ 66 /* For one page, it's not worth testing the split_tlb variable */
67 67
68 mb(); 68 mb();
69 mtsp(vma->vm_mm->context,1); 69 mtsp(vma->vm_mm->context,1);
70 purge_tlb_start(); 70 purge_tlb_start(flags);
71 pdtlb(addr); 71 pdtlb(addr);
72 pitlb(addr); 72 pitlb(addr);
73 purge_tlb_end(); 73 purge_tlb_end(flags);
74} 74}
75 75
76void __flush_tlb_range(unsigned long sid, 76void __flush_tlb_range(unsigned long sid,
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);
397 397
398void clear_user_page_asm(void *page, unsigned long vaddr) 398void clear_user_page_asm(void *page, unsigned long vaddr)
399{ 399{
400 unsigned long flags;
400 /* This function is implemented in assembly in pacache.S */ 401 /* This function is implemented in assembly in pacache.S */
401 extern void __clear_user_page_asm(void *page, unsigned long vaddr); 402 extern void __clear_user_page_asm(void *page, unsigned long vaddr);
402 403
403 purge_tlb_start(); 404 purge_tlb_start(flags);
404 __clear_user_page_asm(page, vaddr); 405 __clear_user_page_asm(page, vaddr);
405 purge_tlb_end(); 406 purge_tlb_end(flags);
406} 407}
407 408
408#define FLUSH_THRESHOLD 0x80000 /* 0.5MB */ 409#define FLUSH_THRESHOLD 0x80000 /* 0.5MB */
@@ -443,20 +444,24 @@ extern void clear_user_page_asm(void *page, unsigned long vaddr);
443 444
444void clear_user_page(void *page, unsigned long vaddr, struct page *pg) 445void clear_user_page(void *page, unsigned long vaddr, struct page *pg)
445{ 446{
447 unsigned long flags;
448
446 purge_kernel_dcache_page((unsigned long)page); 449 purge_kernel_dcache_page((unsigned long)page);
447 purge_tlb_start(); 450 purge_tlb_start(flags);
448 pdtlb_kernel(page); 451 pdtlb_kernel(page);
449 purge_tlb_end(); 452 purge_tlb_end(flags);
450 clear_user_page_asm(page, vaddr); 453 clear_user_page_asm(page, vaddr);
451} 454}
452EXPORT_SYMBOL(clear_user_page); 455EXPORT_SYMBOL(clear_user_page);
453 456
454void flush_kernel_dcache_page_addr(void *addr) 457void flush_kernel_dcache_page_addr(void *addr)
455{ 458{
459 unsigned long flags;
460
456 flush_kernel_dcache_page_asm(addr); 461 flush_kernel_dcache_page_asm(addr);
457 purge_tlb_start(); 462 purge_tlb_start(flags);
458 pdtlb_kernel(addr); 463 pdtlb_kernel(addr);
459 purge_tlb_end(); 464 purge_tlb_end(flags);
460} 465}
461EXPORT_SYMBOL(flush_kernel_dcache_page_addr); 466EXPORT_SYMBOL(flush_kernel_dcache_page_addr);
462 467
@@ -489,8 +494,10 @@ void __flush_tlb_range(unsigned long sid, unsigned long start,
489 if (npages >= 512) /* 2MB of space: arbitrary, should be tuned */ 494 if (npages >= 512) /* 2MB of space: arbitrary, should be tuned */
490 flush_tlb_all(); 495 flush_tlb_all();
491 else { 496 else {
497 unsigned long flags;
498
492 mtsp(sid, 1); 499 mtsp(sid, 1);
493 purge_tlb_start(); 500 purge_tlb_start(flags);
494 if (split_tlb) { 501 if (split_tlb) {
495 while (npages--) { 502 while (npages--) {
496 pdtlb(start); 503 pdtlb(start);
@@ -503,7 +510,7 @@ void __flush_tlb_range(unsigned long sid, unsigned long start,
503 start += PAGE_SIZE; 510 start += PAGE_SIZE;
504 } 511 }
505 } 512 }
506 purge_tlb_end(); 513 purge_tlb_end(flags);
507 } 514 }
508} 515}
509 516
diff --git a/arch/parisc/kernel/pci-dma.c b/arch/parisc/kernel/pci-dma.c
index 7d927eac932b..c07f618ff7da 100644
--- a/arch/parisc/kernel/pci-dma.c
+++ b/arch/parisc/kernel/pci-dma.c
@@ -90,12 +90,14 @@ static inline int map_pte_uncached(pte_t * pte,
90 if (end > PMD_SIZE) 90 if (end > PMD_SIZE)
91 end = PMD_SIZE; 91 end = PMD_SIZE;
92 do { 92 do {
93 unsigned long flags;
94
93 if (!pte_none(*pte)) 95 if (!pte_none(*pte))
94 printk(KERN_ERR "map_pte_uncached: page already exists\n"); 96 printk(KERN_ERR "map_pte_uncached: page already exists\n");
95 set_pte(pte, __mk_pte(*paddr_ptr, PAGE_KERNEL_UNC)); 97 set_pte(pte, __mk_pte(*paddr_ptr, PAGE_KERNEL_UNC));
96 purge_tlb_start(); 98 purge_tlb_start(flags);
97 pdtlb_kernel(orig_vaddr); 99 pdtlb_kernel(orig_vaddr);
98 purge_tlb_end(); 100 purge_tlb_end(flags);
99 vaddr += PAGE_SIZE; 101 vaddr += PAGE_SIZE;
100 orig_vaddr += PAGE_SIZE; 102 orig_vaddr += PAGE_SIZE;
101 (*paddr_ptr) += PAGE_SIZE; 103 (*paddr_ptr) += PAGE_SIZE;
@@ -168,11 +170,13 @@ static inline void unmap_uncached_pte(pmd_t * pmd, unsigned long vaddr,
168 if (end > PMD_SIZE) 170 if (end > PMD_SIZE)
169 end = PMD_SIZE; 171 end = PMD_SIZE;
170 do { 172 do {
173 unsigned long flags;
171 pte_t page = *pte; 174 pte_t page = *pte;
175
172 pte_clear(&init_mm, vaddr, pte); 176 pte_clear(&init_mm, vaddr, pte);
173 purge_tlb_start(); 177 purge_tlb_start(flags);
174 pdtlb_kernel(orig_vaddr); 178 pdtlb_kernel(orig_vaddr);
175 purge_tlb_end(); 179 purge_tlb_end(flags);
176 vaddr += PAGE_SIZE; 180 vaddr += PAGE_SIZE;
177 orig_vaddr += PAGE_SIZE; 181 orig_vaddr += PAGE_SIZE;
178 pte++; 182 pte++;