add new system file

hc

2024-02-20 102a0743326a03cd1a1202ceda21e175b7d3575c

 kernel/arch/nds32/mm/fault.c
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@@ -9,8 +9,8 @@
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 #include <linux/init.h>
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 #include <linux/hardirq.h>
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 #include <linux/uaccess.h>
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+#include <linux/perf_event.h>
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-#include <asm/pgtable.h>
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 #include <asm/tlbflush.h>
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 extern void die(const char *str, struct pt_regs *regs, long err);
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@@ -30,6 +30,8 @@
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 	pr_alert("[%08lx] *pgd=%08lx", addr, pgd_val(*pgd));
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 	do {
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+		p4d_t *p4d;
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+		pud_t *pud;
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 		pmd_t *pmd;
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 		if (pgd_none(*pgd))
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@@ -40,7 +42,9 @@
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 			break;
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 		}
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-		pmd = pmd_offset(pgd, addr);
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+		p4d = p4d_offset(pgd, addr);
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+		pud = pud_offset(p4d, addr);
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+		pmd = pmd_offset(pud, addr);
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 #if PTRS_PER_PMD != 1
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 		pr_alert(", *pmd=%08lx", pmd_val(*pmd));
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 #endif
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@@ -74,8 +78,8 @@
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 	struct vm_area_struct *vma;
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 	int si_code;
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 	vm_fault_t fault;
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-	unsigned int mask = VM_READ | VM_WRITE | VM_EXEC;
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-	unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
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+	unsigned int mask = VM_ACCESS_FLAGS;
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+	unsigned int flags = FAULT_FLAG_DEFAULT;
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 	error_code = error_code & (ITYPE_mskINST | ITYPE_mskETYPE);
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 	tsk = current;
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@@ -117,17 +121,19 @@
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 	if (unlikely(faulthandler_disabled() || !mm))
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 		goto no_context;
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+	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr);
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+
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 	/*
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 	 * As per x86, we may deadlock here. However, since the kernel only
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 	 * validly references user space from well defined areas of the code,
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 	 * we can bug out early if this is from code which shouldn't.
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 	 */
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-	if (unlikely(!down_read_trylock(&mm->mmap_sem))) {
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+	if (unlikely(!mmap_read_trylock(mm))) {
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 		if (!user_mode(regs) &&
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 		    !search_exception_tables(instruction_pointer(regs)))
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 			goto no_context;
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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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 	} else {
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 		/*
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 		 * The above down_read_trylock() might have succeeded in which
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@@ -169,8 +175,6 @@
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 			mask = VM_EXEC;
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 		else {
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 			mask = VM_READ | VM_WRITE;
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-			if (vma->vm_flags & VM_WRITE)
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-				flags |= FAULT_FLAG_WRITE;
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 		}
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 	} else if (entry == ENTRY_TLB_MISC) {
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 		switch (error_code & ITYPE_mskETYPE) {
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@@ -204,14 +208,14 @@
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 	 * the fault.
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 	 */
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-	fault = handle_mm_fault(vma, addr, flags);
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+	fault = handle_mm_fault(vma, addr, flags, regs);
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 	/*
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 	 * If we need to retry but a fatal signal is pending, handle the
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-	 * signal first. We do not need to release the mmap_sem because it
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+	 * signal first. We do not need to release the mmap_lock because it
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 	 * would already be released in __lock_page_or_retry in mm/filemap.c.
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 	 */
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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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 		if (!user_mode(regs))
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 			goto no_context;
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 		return;
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@@ -226,21 +230,11 @@
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 			goto bad_area;
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 	}
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-	/*
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-	 * Major/minor page fault accounting is only done on the initial
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-	 * attempt. If we go through a retry, it is extremely likely that the
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-	 * 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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-			tsk->maj_flt++;
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-		else
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-			tsk->min_flt++;
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 		if (fault & VM_FAULT_RETRY) {
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-			flags &= ~FAULT_FLAG_ALLOW_RETRY;
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 			flags |= FAULT_FLAG_TRIED;
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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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@@ -248,7 +242,7 @@
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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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@@ -256,7 +250,7 @@
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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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@@ -266,7 +260,7 @@
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 		tsk->thread.address = addr;
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 		tsk->thread.error_code = error_code;
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 		tsk->thread.trap_no = entry;
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-		force_sig_fault(SIGSEGV, si_code, (void __user *)addr, tsk);
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+		force_sig_fault(SIGSEGV, si_code, (void __user *)addr);
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 		return;
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 	}
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@@ -316,14 +310,14 @@
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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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@@ -335,7 +329,7 @@
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 	tsk->thread.address = addr;
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 	tsk->thread.error_code = error_code;
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 	tsk->thread.trap_no = entry;
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-	force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *)addr, tsk);
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+	force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *)addr);
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 	return;
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@@ -354,6 +348,7 @@
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 		unsigned int index = pgd_index(addr);
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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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@@ -364,8 +359,13 @@
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 		if (!pgd_present(*pgd_k))
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 			goto no_context;
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-		pud = pud_offset(pgd, addr);
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-		pud_k = pud_offset(pgd_k, addr);
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+		p4d = p4d_offset(pgd, addr);
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+		p4d_k = p4d_offset(pgd_k, addr);
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+		if (!p4d_present(*p4d_k))
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+			goto no_context;
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+
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+		pud = pud_offset(p4d, addr);
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+		pud_k = pud_offset(p4d_k, addr);
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 		if (!pud_present(*pud_k))
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 			goto no_context;
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