MIPS: mm: Standardise on _PAGE_NO_READ, drop _PAGE_READ

Ever since support for RI/XI was implemented by commit 6dd9344cfc41
("MIPS: Implement Read Inhibit/eXecute Inhibit") we've had a mixture of
_PAGE_READ & _PAGE_NO_READ bits. Rather than keep both around, switch
away from using _PAGE_READ to determine page presence & instead invert
the use to _PAGE_NO_READ. Wherever we formerly had no definition for
_PAGE_NO_READ, change what was _PAGE_READ to _PAGE_NO_READ. The end
result is that we consistently use _PAGE_NO_READ to determine whether a
page is readable, regardless of whether RI/XI is implemented.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Cc: David Daney <david.daney@cavium.com>
Cc: Huacai Chen <chenhc@lemote.com>
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Alex Smith <alex.smith@imgtec.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/13116/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/include/asm/pgtable-bits.h

@@ -49,7 +49,6 @@ enum pgtable_bits {
 
 	/* Used only by software (masked out before writing EntryLo*) */
 	_PAGE_PRESENT_SHIFT = 24,
-	_PAGE_READ_SHIFT,
 	_PAGE_WRITE_SHIFT,
 	_PAGE_ACCESSED_SHIFT,
 	_PAGE_MODIFIED_SHIFT,
@@ -66,7 +65,7 @@ enum pgtable_bits {
 enum pgtable_bits {
 	/* Used only by software (writes to EntryLo ignored) */
 	_PAGE_PRESENT_SHIFT,
-	_PAGE_READ_SHIFT,
+	_PAGE_NO_READ_SHIFT,
 	_PAGE_WRITE_SHIFT,
 	_PAGE_ACCESSED_SHIFT,
 	_PAGE_MODIFIED_SHIFT,
@@ -85,7 +84,7 @@ enum pgtable_bits {
 	/* Used only by software (masked out before writing EntryLo*) */
 	_PAGE_PRESENT_SHIFT,
 #if !defined(CONFIG_CPU_MIPSR2) && !defined(CONFIG_CPU_MIPSR6)
-	_PAGE_READ_SHIFT,
+	_PAGE_NO_READ_SHIFT,
 #endif
 	_PAGE_WRITE_SHIFT,
 	_PAGE_ACCESSED_SHIFT,
@@ -98,7 +97,6 @@ enum pgtable_bits {
 #if defined(CONFIG_CPU_MIPSR2) || defined(CONFIG_CPU_MIPSR6)
 	_PAGE_NO_EXEC_SHIFT,
 	_PAGE_NO_READ_SHIFT,
-	_PAGE_READ_SHIFT = _PAGE_NO_READ_SHIFT,
 #endif
 	_PAGE_GLOBAL_SHIFT,
 	_PAGE_VALID_SHIFT,
@@ -110,11 +108,6 @@ enum pgtable_bits {
 
 /* Used only by software */
 #define _PAGE_PRESENT		(1 << _PAGE_PRESENT_SHIFT)
-#if defined(CONFIG_CPU_MIPSR2) || defined(CONFIG_CPU_MIPSR6)
-# define _PAGE_READ		(cpu_has_rixi ? 0 : (1 << _PAGE_READ_SHIFT))
-#else
-# define _PAGE_READ		(1 << _PAGE_READ_SHIFT)
-#endif
 #define _PAGE_WRITE		(1 << _PAGE_WRITE_SHIFT)
 #define _PAGE_ACCESSED		(1 << _PAGE_ACCESSED_SHIFT)
 #define _PAGE_MODIFIED		(1 << _PAGE_MODIFIED_SHIFT)
@@ -125,11 +118,10 @@ enum pgtable_bits {
 /* Used by TLB hardware (placed in EntryLo*) */
 #if (defined(CONFIG_PHYS_ADDR_T_64BIT) && defined(CONFIG_CPU_MIPS32))
 # define _PAGE_NO_EXEC		(1 << _PAGE_NO_EXEC_SHIFT)
-# define _PAGE_NO_READ		(1 << _PAGE_NO_READ_SHIFT)
 #elif defined(CONFIG_CPU_MIPSR2) || defined(CONFIG_CPU_MIPSR6)
 # define _PAGE_NO_EXEC		(cpu_has_rixi ? (1 << _PAGE_NO_EXEC_SHIFT) : 0)
-# define _PAGE_NO_READ		(cpu_has_rixi ? (1 << _PAGE_NO_READ_SHIFT) : 0)
 #endif
+#define _PAGE_NO_READ		(1 << _PAGE_NO_READ_SHIFT)
 #define _PAGE_GLOBAL		(1 << _PAGE_GLOBAL_SHIFT)
 #define _PAGE_VALID		(1 << _PAGE_VALID_SHIFT)
 #define _PAGE_DIRTY		(1 << _PAGE_DIRTY_SHIFT)
@@ -145,9 +137,6 @@ enum pgtable_bits {
 #ifndef _PAGE_NO_EXEC
 #define _PAGE_NO_EXEC		0
 #endif
-#ifndef _PAGE_NO_READ
-#define _PAGE_NO_READ		0
-#endif
 
 #define _PAGE_SILENT_READ	_PAGE_VALID
 #define _PAGE_SILENT_WRITE	_PAGE_DIRTY
@@ -245,7 +234,7 @@ static inline uint64_t pte_to_entrylo(unsigned long pte_val)
 #define _CACHE_UNCACHED_ACCELERATED	(7<<_CACHE_SHIFT)
 #endif
 
-#define __READABLE	(_PAGE_SILENT_READ | _PAGE_READ | _PAGE_ACCESSED)
+#define __READABLE	(_PAGE_SILENT_READ | _PAGE_ACCESSED)
 #define __WRITEABLE	(_PAGE_SILENT_WRITE | _PAGE_WRITE | _PAGE_MODIFIED)
 
 #define _PAGE_CHG_MASK	(_PAGE_ACCESSED | _PAGE_MODIFIED |	\

arch/mips/include/asm/pgtable.h

@@ -23,18 +23,19 @@
 struct mm_struct;
 struct vm_area_struct;
 
-#define PAGE_NONE	__pgprot(_PAGE_PRESENT | _CACHE_CACHABLE_NONCOHERENT)
-#define PAGE_SHARED	__pgprot(_PAGE_PRESENT | _PAGE_WRITE | _PAGE_READ | \
+#define PAGE_NONE	__pgprot(_PAGE_PRESENT | _PAGE_NO_READ | \
+				 _CACHE_CACHABLE_NONCOHERENT)
+#define PAGE_SHARED	__pgprot(_PAGE_PRESENT | _PAGE_WRITE | \
 				 _page_cachable_default)
-#define PAGE_COPY	__pgprot(_PAGE_PRESENT | _PAGE_READ | _PAGE_NO_EXEC | \
+#define PAGE_COPY	__pgprot(_PAGE_PRESENT | _PAGE_NO_EXEC | \
 				 _page_cachable_default)
-#define PAGE_READONLY	__pgprot(_PAGE_PRESENT | _PAGE_READ | \
+#define PAGE_READONLY	__pgprot(_PAGE_PRESENT | \
 				 _page_cachable_default)
 #define PAGE_KERNEL	__pgprot(_PAGE_PRESENT | __READABLE | __WRITEABLE | \
 				 _PAGE_GLOBAL | _page_cachable_default)
 #define PAGE_KERNEL_NC	__pgprot(_PAGE_PRESENT | __READABLE | __WRITEABLE | \
 				 _PAGE_GLOBAL | _CACHE_CACHABLE_NONCOHERENT)
-#define PAGE_USERIO	__pgprot(_PAGE_PRESENT | _PAGE_READ | _PAGE_WRITE | \
+#define PAGE_USERIO	__pgprot(_PAGE_PRESENT | _PAGE_WRITE | \
 				 _page_cachable_default)
 #define PAGE_KERNEL_UNCACHED __pgprot(_PAGE_PRESENT | __READABLE | \
 			__WRITEABLE | _PAGE_GLOBAL | _CACHE_UNCACHED)
@@ -338,7 +339,7 @@ static inline pte_t pte_mkdirty(pte_t pte)
 static inline pte_t pte_mkyoung(pte_t pte)
 {
 	pte.pte_low |= _PAGE_ACCESSED;
-	if (pte.pte_low & _PAGE_READ)
+	if (!(pte.pte_low & _PAGE_NO_READ))
 		pte.pte_high |= _PAGE_SILENT_READ;
 	return pte;
 }
@@ -384,13 +385,8 @@ static inline pte_t pte_mkdirty(pte_t pte)
 static inline pte_t pte_mkyoung(pte_t pte)
 {
 	pte_val(pte) |= _PAGE_ACCESSED;
-#if defined(CONFIG_CPU_MIPSR2) || defined(CONFIG_CPU_MIPSR6) || defined(CONFIG_CPU_LOONGSON3)
 	if (!(pte_val(pte) & _PAGE_NO_READ))
 		pte_val(pte) |= _PAGE_SILENT_READ;
-	else
-#endif
-	if (pte_val(pte) & _PAGE_READ)
-		pte_val(pte) |= _PAGE_SILENT_READ;
 	return pte;
 }
 
@@ -570,13 +566,8 @@ static inline pmd_t pmd_mkyoung(pmd_t pmd)
 {
 	pmd_val(pmd) |= _PAGE_ACCESSED;
 
-#if defined(CONFIG_CPU_MIPSR2) || defined(CONFIG_CPU_MIPSR6) || defined(CONFIG_CPU_LOONGSON3)
 	if (!(pmd_val(pmd) & _PAGE_NO_READ))
 		pmd_val(pmd) |= _PAGE_SILENT_READ;
-	else
-#endif
-	if (pmd_val(pmd) & _PAGE_READ)
-		pmd_val(pmd) |= _PAGE_SILENT_READ;
 
 	return pmd;
 }

arch/mips/mm/tlbex.c

@@ -234,20 +234,16 @@ static void output_pgtable_bits_defines(void)
 	pr_debug("\n");
 
 	pr_define("_PAGE_PRESENT_SHIFT %d\n", _PAGE_PRESENT_SHIFT);
-	pr_define("_PAGE_READ_SHIFT %d\n", _PAGE_READ_SHIFT);
+	pr_define("_PAGE_NO_READ_SHIFT %d\n", _PAGE_NO_READ_SHIFT);
 	pr_define("_PAGE_WRITE_SHIFT %d\n", _PAGE_WRITE_SHIFT);
 	pr_define("_PAGE_ACCESSED_SHIFT %d\n", _PAGE_ACCESSED_SHIFT);
 	pr_define("_PAGE_MODIFIED_SHIFT %d\n", _PAGE_MODIFIED_SHIFT);
 #ifdef CONFIG_MIPS_HUGE_TLB_SUPPORT
 	pr_define("_PAGE_HUGE_SHIFT %d\n", _PAGE_HUGE_SHIFT);
 #endif
-#if defined(CONFIG_CPU_MIPSR2) || defined(CONFIG_CPU_MIPSR6)
-	if (cpu_has_rixi) {
 #ifdef _PAGE_NO_EXEC_SHIFT
+	if (cpu_has_rixi)
 		pr_define("_PAGE_NO_EXEC_SHIFT %d\n", _PAGE_NO_EXEC_SHIFT);
-		pr_define("_PAGE_NO_READ_SHIFT %d\n", _PAGE_NO_READ_SHIFT);
-#endif
-	}
 #endif
 	pr_define("_PAGE_GLOBAL_SHIFT %d\n", _PAGE_GLOBAL_SHIFT);
 	pr_define("_PAGE_VALID_SHIFT %d\n", _PAGE_VALID_SHIFT);
@@ -1728,9 +1724,8 @@ build_pte_present(u32 **p, struct uasm_reloc **r,
 			cur = t;
 		}
 		uasm_i_andi(p, t, cur,
-			(_PAGE_PRESENT | _PAGE_READ) >> _PAGE_PRESENT_SHIFT);
-		uasm_i_xori(p, t, t,
-			(_PAGE_PRESENT | _PAGE_READ) >> _PAGE_PRESENT_SHIFT);
+			(_PAGE_PRESENT | _PAGE_NO_READ) >> _PAGE_PRESENT_SHIFT);
+		uasm_i_xori(p, t, t, _PAGE_PRESENT >> _PAGE_PRESENT_SHIFT);
 		uasm_il_bnez(p, r, t, lid);
 		if (pte == t)
 			/* You lose the SMP race :-(*/