add new system file

hc

2024-02-20 102a0743326a03cd1a1202ceda21e175b7d3575c

 kernel/arch/nios2/mm/fault.c
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@@ -24,7 +24,7 @@
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 #include <linux/mm.h>
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 #include <linux/extable.h>
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 #include <linux/uaccess.h>
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-#include <linux/ptrace.h>
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+#include <linux/perf_event.h>
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 #include <asm/mmu_context.h>
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 #include <asm/traps.h>
..
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@@ -48,7 +48,7 @@
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 	struct mm_struct *mm = tsk->mm;
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 	int code = SEGV_MAPERR;
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 	vm_fault_t fault;
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-	unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
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+	unsigned int flags = FAULT_FLAG_DEFAULT;
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 	cause >>= 2;
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..
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@@ -84,11 +84,13 @@
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 	if (user_mode(regs))
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 		flags |= FAULT_FLAG_USER;
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-	if (!down_read_trylock(&mm->mmap_sem)) {
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+	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
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+
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+	if (!mmap_read_trylock(mm)) {
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 		if (!user_mode(regs) && !search_exception_tables(regs->ea))
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 			goto bad_area_nosemaphore;
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 retry:
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-		down_read(&mm->mmap_sem);
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+		mmap_read_lock(mm);
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 	}
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 	vma = find_vma(mm, address);
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@@ -132,9 +134,9 @@
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 	 * make sure we exit gracefully rather than endlessly redo
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 	 * the fault.
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 	 */
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-	fault = handle_mm_fault(vma, address, flags);
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+	fault = handle_mm_fault(vma, address, flags, regs);
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-	if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
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+	if (fault_signal_pending(fault, regs))
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 		return;
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 	if (unlikely(fault & VM_FAULT_ERROR)) {
..
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@@ -147,24 +149,12 @@
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 		BUG();
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 	}
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-	/*
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-	 * Major/minor page fault accounting is only done on the
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-	 * initial attempt. If we go through a retry, it is extremely
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-	 * likely that the page will be found in page cache at that point.
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-	 */
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 	if (flags & FAULT_FLAG_ALLOW_RETRY) {
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-		if (fault & VM_FAULT_MAJOR)
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-			current->maj_flt++;
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-		else
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-			current->min_flt++;
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 		if (fault & VM_FAULT_RETRY) {
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-			/* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk
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-			 * of starvation. */
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-			flags &= ~FAULT_FLAG_ALLOW_RETRY;
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 			flags |= FAULT_FLAG_TRIED;
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 			/*
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-			 * No need to up_read(&mm->mmap_sem) as we would
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+			 * No need to mmap_read_unlock(mm) as we would
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 			 * have already released it in __lock_page_or_retry
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 			 * in mm/filemap.c.
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 			 */
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@@ -173,7 +163,7 @@
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 		}
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 	}
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-	up_read(&mm->mmap_sem);
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+	mmap_read_unlock(mm);
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 	return;
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 /*
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@@ -181,7 +171,7 @@
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  * Fix it, but check if it's kernel or user first..
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  */
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 bad_area:
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-	up_read(&mm->mmap_sem);
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+	mmap_read_unlock(mm);
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 bad_area_nosemaphore:
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 	/* User mode accesses just cause a SIGSEGV */
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@@ -219,14 +209,14 @@
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  * us unable to handle the page fault gracefully.
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  */
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 out_of_memory:
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-	up_read(&mm->mmap_sem);
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+	mmap_read_unlock(mm);
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 	if (!user_mode(regs))
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 		goto no_context;
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 	pagefault_out_of_memory();
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 	return;
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 do_sigbus:
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-	up_read(&mm->mmap_sem);
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+	mmap_read_unlock(mm);
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 	/* Kernel mode? Handle exceptions or die */
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 	if (!user_mode(regs))
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@@ -246,6 +236,7 @@
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 		 */
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 		int offset = pgd_index(address);
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 		pgd_t *pgd, *pgd_k;
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+		p4d_t *p4d, *p4d_k;
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 		pud_t *pud, *pud_k;
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 		pmd_t *pmd, *pmd_k;
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 		pte_t *pte_k;
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@@ -257,8 +248,12 @@
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 			goto no_context;
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 		set_pgd(pgd, *pgd_k);
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-		pud = pud_offset(pgd, address);
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-		pud_k = pud_offset(pgd_k, address);
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+		p4d = p4d_offset(pgd, address);
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+		p4d_k = p4d_offset(pgd_k, address);
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+		if (!p4d_present(*p4d_k))
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+			goto no_context;
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+		pud = pud_offset(p4d, address);
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+		pud_k = pud_offset(p4d_k, address);
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 		if (!pud_present(*pud_k))
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 			goto no_context;
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 		pmd = pmd_offset(pud, address);
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@@ -271,7 +266,7 @@
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 		if (!pte_present(*pte_k))
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 			goto no_context;
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-		flush_tlb_one(address);
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+		flush_tlb_kernel_page(address);
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 		return;
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 	}
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 }