csky: Remove prologue of page fault handler in entry.S

There is a prologue on page fault handler which marking pages dirty
and/or accessed in page attributes, but all of these have been
handled in handle_pte_fault.

- Add flush_tlb_one in vmalloc page fault instead of prologue.
- Using cmxchg_fixup C codes in do_page_fault instead of ASM one.

Signed-off-by: Guo Ren <[e-mail]>

arch/csky/kernel/atomic.S

···
 2:
 	sync.is
 #else
-1:
+GLOBAL(csky_cmpxchg_ldw)
 	ldw	a3, (a2)
 	cmpne	a0, a3
 	bt16	3f
-2:
+GLOBAL(csky_cmpxchg_stw)
 	stw	a1, (a2)
 3:
 #endif
···
 	KSPTOUSP
 	rte
 END(csky_cmpxchg)
-
-#ifndef CONFIG_CPU_HAS_LDSTEX
-/*
- * Called from tlbmodified exception
- */
-ENTRY(csky_cmpxchg_fixup)
-	mfcr	a0, epc
-	lrw	a1, 2b
-	cmpne	a1, a0
-	bt	1f
-	subi	a1, (2b - 1b)
-	stw	a1, (sp, LSAVE_PC)
-1:
-	rts
-END(csky_cmpxchg_fixup)
-#endif

arch/csky/kernel/entry.S

···
 #include <asm/page.h>
 #include <asm/thread_info.h>
 
-#define PTE_INDX_MSK    0xffc
-#define PTE_INDX_SHIFT  10
-#define _PGDIR_SHIFT    22
-
 .macro	zero_fp
 #ifdef CONFIG_STACKTRACE
 	movi	r8, 0
···
 #endif
 .endm
 
-.macro tlbop_begin name, val0, val1, val2
-ENTRY(csky_\name)
-	mtcr    a3, ss2
-	mtcr    r6, ss3
-	mtcr    a2, ss4
-
-	RD_PGDR	r6
-	RD_MEH	a3
-	WR_MEH	a3
-#ifdef CONFIG_CPU_HAS_TLBI
-	tlbi.vaas a3
-	sync.is
-
-	btsti	a3, 31
-	bf	1f
-	RD_PGDR_K r6
-1:
-#else
-	bgeni	a2, 31
-	WR_MCIR	a2
-	bgeni	a2, 25
-	WR_MCIR	a2
-#endif
-	bclri   r6, 0
-	lrw	a2, PAGE_OFFSET
-	add	r6, a2
-	lrw	a2, va_pa_offset
-	ld.w	a2, (a2, 0)
-	subu	r6, a2
-
-	mov     a2, a3
-	lsri    a2, _PGDIR_SHIFT
-	lsli    a2, 2
-	addu    r6, a2
-	ldw     r6, (r6)
-
-	lrw	a2, PAGE_OFFSET
-	add	r6, a2
-	lrw	a2, va_pa_offset
-	ld.w	a2, (a2, 0)
-	subu	r6, a2
-
-	lsri    a3, PTE_INDX_SHIFT
-	lrw     a2, PTE_INDX_MSK
-	and     a3, a2
-	addu    r6, a3
-	ldw     a3, (r6)
-
-	movi	a2, (_PAGE_PRESENT | \val0)
-	and     a3, a2
-	cmpne   a3, a2
-	bt	\name
-
-	/* First read/write the page, just update the flags */
-	ldw     a3, (r6)
-	bgeni   a2, PAGE_VALID_BIT
-	bseti   a2, PAGE_ACCESSED_BIT
-	bseti   a2, \val1
-	bseti   a2, \val2
-	or      a3, a2
-	stw     a3, (r6)
-
-	/* Some cpu tlb-hardrefill bypass the cache */
-#ifdef CONFIG_CPU_NEED_TLBSYNC
-	movi	a2, 0x22
-	bseti	a2, 6
-	mtcr	r6, cr22
-	mtcr	a2, cr17
-	sync
-#endif
-
-	mfcr    a3, ss2
-	mfcr    r6, ss3
-	mfcr    a2, ss4
-	rte
-\name:
-	mfcr    a3, ss2
-	mfcr    r6, ss3
-	mfcr    a2, ss4
+.text
+ENTRY(csky_pagefault)
 	SAVE_ALL 0
-.endm
-.macro tlbop_end is_write
 	zero_fp
 	context_tracking
-	RD_MEH	a2
 	psrset  ee, ie
 	mov     a0, sp
-	movi    a1, \is_write
 	jbsr    do_page_fault
 	jmpi    ret_from_exception
-.endm
-
-.text
-
-tlbop_begin tlbinvalidl, _PAGE_READ, PAGE_VALID_BIT, PAGE_ACCESSED_BIT
-tlbop_end 0
-
-tlbop_begin tlbinvalids, _PAGE_WRITE, PAGE_DIRTY_BIT, PAGE_MODIFIED_BIT
-tlbop_end 1
-
-tlbop_begin tlbmodified, _PAGE_WRITE, PAGE_DIRTY_BIT, PAGE_MODIFIED_BIT
-#ifndef CONFIG_CPU_HAS_LDSTEX
-jbsr csky_cmpxchg_fixup
-#endif
-tlbop_end 1
 
 ENTRY(csky_systemcall)
 	SAVE_ALL TRAP0_SIZE

arch/csky/kernel/traps.c

···
 asmlinkage void csky_get_tls(void);
 asmlinkage void csky_irq(void);
 
-asmlinkage void csky_tlbinvalidl(void);
-asmlinkage void csky_tlbinvalids(void);
-asmlinkage void csky_tlbmodified(void);
+asmlinkage void csky_pagefault(void);
 
 /* Defined in head.S */
 asmlinkage void _start_smp_secondary(void);
···
 	VEC_INIT(VEC_TRAP3, csky_get_tls);
 
 	/* setup MMU TLB exception */
-	VEC_INIT(VEC_TLBINVALIDL, csky_tlbinvalidl);
-	VEC_INIT(VEC_TLBINVALIDS, csky_tlbinvalids);
-	VEC_INIT(VEC_TLBMODIFIED, csky_tlbmodified);
+	VEC_INIT(VEC_TLBINVALIDL, csky_pagefault);
+	VEC_INIT(VEC_TLBINVALIDS, csky_pagefault);
+	VEC_INIT(VEC_TLBMODIFIED, csky_pagefault);
 
 #ifdef CONFIG_CPU_HAS_FPU
 	init_fpu();

arch/csky/mm/fault.c

···
 	return 0;
 }
 
+static inline bool is_write(struct pt_regs *regs)
+{
+	switch (trap_no(regs)) {
+	case VEC_TLBINVALIDS:
+		return true;
+	case VEC_TLBMODIFIED:
+		return true;
+	}
+
+	return false;
+}
+
+#ifdef CONFIG_CPU_HAS_LDSTEX
+static inline void csky_cmpxchg_fixup(struct pt_regs *regs)
+{
+	return;
+}
+#else
+extern unsigned long csky_cmpxchg_ldw;
+extern unsigned long csky_cmpxchg_stw;
+static inline void csky_cmpxchg_fixup(struct pt_regs *regs)
+{
+	if (trap_no(regs) != VEC_TLBMODIFIED)
+		return;
+
+	if (instruction_pointer(regs) == csky_cmpxchg_stw)
+		instruction_pointer_set(regs, csky_cmpxchg_ldw);
+	return;
+}
+#endif
+
 /*
  * This routine handles page faults. It determines the address,
  * and the problem, and then passes it off to one of the appropriate
  * routines.
  */
-asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long write,
-			      unsigned long mmu_meh)
+asmlinkage void do_page_fault(struct pt_regs *regs)
 {
 	struct vm_area_struct *vma = NULL;
 	struct task_struct *tsk = current;
 	struct mm_struct *mm = tsk->mm;
 	int si_code;
 	int fault;
-	unsigned long address = mmu_meh & PAGE_MASK;
+	unsigned long address = read_mmu_entryhi() & PAGE_MASK;
+
+	csky_cmpxchg_fixup(regs);
 
 	if (kprobe_page_fault(regs, tsk->thread.trap_no))
 		return;
···
 		pte_k = pte_offset_kernel(pmd_k, address);
 		if (!pte_present(*pte_k))
 			goto no_context;
+
+		flush_tlb_one(address);
+
 		return;
 	}
 
···
 good_area:
 	si_code = SEGV_ACCERR;
 
-	if (write) {
+	if (is_write(regs)) {
 		if (!(vma->vm_flags & VM_WRITE))
 			goto bad_area;
 	} else {
···
 	 * make sure we exit gracefully rather than endlessly redo
 	 * the fault.
 	 */
-	fault = handle_mm_fault(vma, address, write ? FAULT_FLAG_WRITE : 0,
+	fault = handle_mm_fault(vma, address, is_write(regs) ? FAULT_FLAG_WRITE : 0,
 				regs);
 	if (unlikely(fault & VM_FAULT_ERROR)) {
 		if (fault & VM_FAULT_OOM)