@@ -543,7 +543,8 @@ void flush_cache_mm(struct mm_struct *mm)
rp3440, etc. So, avoid it if the mm isn't too big. */
if ((!IS_ENABLED(CONFIG_SMP) || !arch_irqs_disabled()) &&
mm_total_size(mm) >= parisc_cache_flush_threshold) {
- flush_tlb_all();
+ if (mm->context)
+ flush_tlb_all();
flush_cache_all();
return;
}
@@ -571,6 +572,8 @@ void flush_cache_mm(struct mm_struct *mm)
pfn = pte_pfn(*ptep);
if (!pfn_valid(pfn))
continue;
+ if (unlikely(mm->context))
+ flush_tlb_page(vma, addr);
__flush_cache_page(vma, addr, PFN_PHYS(pfn));
}
}
@@ -579,26 +582,46 @@ void flush_cache_mm(struct mm_struct *mm)
void flush_cache_range(struct vm_area_struct *vma,
unsigned long start, unsigned long end)
{
+ pgd_t *pgd;
+ unsigned long addr;
+
if ((!IS_ENABLED(CONFIG_SMP) || !arch_irqs_disabled()) &&
end - start >= parisc_cache_flush_threshold) {
- flush_tlb_range(vma, start, end);
+ if (vma->vm_mm->context)
+ flush_tlb_range(vma, start, end);
flush_cache_all();
return;
}
- flush_user_dcache_range_asm(start, end);
- if (vma->vm_flags & VM_EXEC)
- flush_user_icache_range_asm(start, end);
- flush_tlb_range(vma, start, end);
+ if (vma->vm_mm->context == mfsp(3)) {
+ flush_user_dcache_range_asm(start, end);
+ if (vma->vm_flags & VM_EXEC)
+ flush_user_icache_range_asm(start, end);
+ flush_tlb_range(vma, start, end);
+ return;
+ }
+
+ pgd = vma->vm_mm->pgd;
+ for (addr = vma->vm_start; addr < vma->vm_end; addr += PAGE_SIZE) {
+ unsigned long pfn;
+ pte_t *ptep = get_ptep(pgd, addr);
+ if (!ptep)
+ continue;
+ pfn = pte_pfn(*ptep);
+ if (pfn_valid(pfn)) {
+ if (unlikely(vma->vm_mm->context))
+ flush_tlb_page(vma, addr);
+ __flush_cache_page(vma, addr, PFN_PHYS(pfn));
+ }
+ }
}
void
flush_cache_page(struct vm_area_struct *vma, unsigned long vmaddr, unsigned long pfn)
{
- BUG_ON(!vma->vm_mm->context);
-
if (pfn_valid(pfn)) {
- flush_tlb_page(vma, vmaddr);
+ if (likely(vma->vm_mm->context))
+ flush_tlb_page(vma, vmaddr);
__flush_cache_page(vma, vmaddr, PFN_PHYS(pfn));
}
}
Just when I had decided that flush_cache_range() was always called with a valid context, Helge reported two cases where the "BUG_ON(!vma->vm_mm->context);" was hit on the phantom buildd: [549700.051761] NET: Registered protocol family 38 [552929.287236] systemd-logind[1672]: New session 11638 of user root. [555698.899355] ------------[ cut here ]------------ [555698.955264] kernel BUG at /mnt/sdb6/linux/linux-4.15.4/arch/parisc/kernel/cache.c:587! [555699.051275] CPU: 1 PID: 3254 Comm: kworker/1:2 Tainted: G D 4.15.0-1-parisc64-smp #1 Debian 4.15.4-1+b1 [555699.179274] Workqueue: events free_ioctx [555699.247243] YZrvWESTHLNXBCVMcbcbcbcbOGFRQPDI [555699.303248] PSW: 00001000000001001111111100001111 Tainted: G D [555699.391249] r00-03 000000ff0804ff0f 0000000040d22760 00000000404a6980 000000014a990b30 [555699.487249] r04-07 0000000040d01f60 00000000f40da000 00000000f40db000 00000041320c1ed8 [555699.583242] r08-11 000000014a9907e8 000000014a990728 000000014a990728 000000411617cd80 [555699.679256] r12-15 000000004107f150 0000000041080e48 0000000040d28760 0000000000000002 [555699.779246] r16-19 0000004133f50140 00000000f40da000 0000000066279900 00000000f40db000 [555699.875239] r20-23 00000000000044d5 fcfaa60000000000 000000014a990728 00000000f40db000 [555699.971239] r24-27 00000000f40db000 00000000f40da000 0000000008478800 0000000040d01f60 [555700.067237] r28-31 0000000007ac0000 000000014a990b00 000000014a990bd0 0000000000001000 [555700.167238] sr00-03 0000000007ac0000 0000000007ac0000 0000000007ac0000 0000000007ac0000 [555700.263236] sr04-07 0000000000000000 0000000000000000 0000000000000000 0000000000000000 [555700.379234] IASQ: 0000000000000000 0000000000000000 IAOQ: 000000004021c0b4 000000004021c0b8 [555700.483234] IIR: 03ffe01f ISR: 0000000000000000 IOR: 0000000000000000 [555700.567233] CPU: 1 CR30: 000000014a990000 CR31: ffffffffffffffff [555700.647233] ORIG_R28: 0000000040d01f60 [555700.695237] IAOQ[0]: flush_cache_range+0x164/0x168 [555700.755237] IAOQ[1]: flush_cache_page+0x0/0x1c8 [555700.811240] RP(r2): unmap_page_range+0xae8/0xb88 [555700.867231] Backtrace: [555700.899249] [<00000000404a6980>] unmap_page_range+0xae8/0xb88 [555700.971238] [<00000000404a6ae0>] unmap_single_vma+0xc0/0x188 [555701.039238] [<00000000404a6cdc>] zap_page_range_single+0x134/0x1f8 [555701.115240] [<00000000404a702c>] unmap_mapping_range+0x1cc/0x208 [555701.191238] [<0000000040461518>] truncate_pagecache+0x98/0x108 [555701.263239] [<0000000040461624>] truncate_setsize+0x9c/0xb8 [555701.331263] [<00000000405d7f30>] put_aio_ring_file+0x80/0x100 [555701.403238] [<00000000405d803c>] aio_free_ring+0x8c/0x290 [555701.467236] [<00000000405d82c0>] free_ioctx+0x80/0x180 [555701.531287] [<0000000040284e6c>] process_one_work+0x21c/0x668 [555701.603237] [<00000000402854c4>] worker_thread+0x20c/0x778 [555701.671235] [<0000000040291d44>] kthread+0x2d4/0x2e0 [555701.735235] [<0000000040204020>] end_fault_vector+0x20/0xc0 This indicates that we need to handle the no context case in flush_cache_range() as we do in flush_cache_mm(). In thinking about this, I realized that we don't need to flush the TLB when there is no context. So, I added context checks to the large flush cases in flush_cache_mm() and flush_cache_range(). The large flush case occurs frequently in flush_cache_mm() and the change should improve fork performance. The v2 version of this change removes the BUG_ON from flush_cache_page() by skipping the TLB flush when there is no context. I also added code to flush the TLB in flush_cache_mm() and flush_cache_range() when we have a context that's not current. Now all three routines handle TLB flushes in a similar manner. Signed-off-by: John David Anglin <dave.anglin@bell.net>