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parisc: ensure broadcast tlb purge runs single threaded

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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>
This commit is contained in:
Helge Deller 2009-06-16 20:51:48 +00:00 committed by Kyle McMartin
parent 84be31be37
commit e82a3b7512
3 changed files with 30 additions and 19 deletions
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14
arch/parisc/include/asm/tlbflush.h
View File

@ -12,14 +12,12 @@
* N class systems, only one PxTLB inter processor broadcast can be
* active at any one time on the Merced bus. This tlb purge
* synchronisation is fairly lightweight and harmless so we activate
* it on all SMP systems not just the N class. We also need to have
* preemption disabled on uniprocessor machines, and spin_lock does that
* nicely.
* it on all systems not just the N class.
*/
extern spinlock_t pa_tlb_lock;
#define purge_tlb_start(x) spin_lock(&pa_tlb_lock)
#define purge_tlb_end(x) spin_unlock(&pa_tlb_lock)
#define purge_tlb_start(flags) spin_lock_irqsave(&pa_tlb_lock, flags)
#define purge_tlb_end(flags) spin_unlock_irqrestore(&pa_tlb_lock, flags)
extern void flush_tlb_all(void);
extern void flush_tlb_all_local(void *);
@ -63,14 +61,16 @@ static inline void flush_tlb_mm(struct mm_struct *mm)
static inline void flush_tlb_page(struct vm_area_struct *vma,
unsigned long addr)
{
unsigned long flags;
/* For one page, it's not worth testing the split_tlb variable */
mb();
mtsp(vma->vm_mm->context,1);
purge_tlb_start();
purge_tlb_start(flags);
pdtlb(addr);
pitlb(addr);
purge_tlb_end();
purge_tlb_end(flags);
}
void __flush_tlb_range(unsigned long sid,

23
arch/parisc/kernel/cache.c
View File

@ -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);
}
}

12
arch/parisc/kernel/pci-dma.c
View File

@ -90,12 +90,14 @@ static inline int map_pte_uncached(pte_t * pte,
if (end > PMD_SIZE)
end = PMD_SIZE;
do {
unsigned long flags;
if (!pte_none(*pte))
printk(KERN_ERR "map_pte_uncached: page already exists\n");
set_pte(pte, __mk_pte(*paddr_ptr, PAGE_KERNEL_UNC));
purge_tlb_start();
purge_tlb_start(flags);
pdtlb_kernel(orig_vaddr);
purge_tlb_end();
purge_tlb_end(flags);
vaddr += PAGE_SIZE;
orig_vaddr += PAGE_SIZE;
(*paddr_ptr) += PAGE_SIZE;
@ -168,11 +170,13 @@ static inline void unmap_uncached_pte(pmd_t * pmd, unsigned long vaddr,
if (end > PMD_SIZE)
end = PMD_SIZE;
do {
unsigned long flags;
pte_t page = *pte;
pte_clear(&init_mm, vaddr, pte);
purge_tlb_start();
purge_tlb_start(flags);
pdtlb_kernel(orig_vaddr);
purge_tlb_end();
purge_tlb_end(flags);
vaddr += PAGE_SIZE;
orig_vaddr += PAGE_SIZE;
pte++;