[PATCH 1/4] MIPS: Replace _PAGE_READ with _PAGE_NO_READ

[PATCH 1/4] MIPS: Replace _PAGE_READ with _PAGE_NO_READ

[Kevin Cernekee]

Reuse more of the same definitions for the non-RIXI and RIXI cases.  This
avoids having special cases for kernel_uses_smartmips_rixi cluttering up
the pgtable*.h files.

On hardware that does not support RI/XI, EntryLo bits 31:30 / 63:62 will
remain unset and RI/XI permissions will not be enforced.

Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
---
 arch/mips/include/asm/pgtable-bits.h |   23 ++++++++---------------
 arch/mips/include/asm/pgtable.h      |   21 ++++++++-------------
 arch/mips/mm/tlbex.c                 |   17 +++++------------
 3 files changed, 21 insertions(+), 40 deletions(-)

diff --git a/arch/mips/include/asm/pgtable-bits.h b/arch/mips/include/asm/pgtable-bits.h
index e9fe7e9..7afba78 100644
--- a/arch/mips/include/asm/pgtable-bits.h
+++ b/arch/mips/include/asm/pgtable-bits.h
@@ -35,7 +35,7 @@
 #if defined(CONFIG_64BIT_PHYS_ADDR) && defined(CONFIG_CPU_MIPS32)
 
 #define _PAGE_PRESENT               (1<<6)  /* implemented in software */
-#define _PAGE_READ                  (1<<7)  /* implemented in software */
+#define _PAGE_NO_READ               (1<<7)  /* implemented in software */
 #define _PAGE_WRITE                 (1<<8)  /* implemented in software */
 #define _PAGE_ACCESSED              (1<<9)  /* implemented in software */
 #define _PAGE_MODIFIED              (1<<10) /* implemented in software */
@@ -53,7 +53,7 @@
 #elif defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
 
 #define _PAGE_PRESENT               (1<<0)  /* implemented in software */
-#define _PAGE_READ                  (1<<1)  /* implemented in software */
+#define _PAGE_NO_READ               (1<<1)  /* implemented in software */
 #define _PAGE_WRITE                 (1<<2)  /* implemented in software */
 #define _PAGE_ACCESSED              (1<<3)  /* implemented in software */
 #define _PAGE_MODIFIED              (1<<4)  /* implemented in software */
@@ -79,11 +79,8 @@
 /* implemented in software */
 #define _PAGE_PRESENT_SHIFT	(0)
 #define _PAGE_PRESENT		(1 << _PAGE_PRESENT_SHIFT)
-/* implemented in software, should be unused if kernel_uses_smartmips_rixi. */
-#define _PAGE_READ_SHIFT	(kernel_uses_smartmips_rixi ? _PAGE_PRESENT_SHIFT : _PAGE_PRESENT_SHIFT + 1)
-#define _PAGE_READ ({if (kernel_uses_smartmips_rixi) BUG(); 1 << _PAGE_READ_SHIFT; })
 /* implemented in software */
-#define _PAGE_WRITE_SHIFT	(_PAGE_READ_SHIFT + 1)
+#define _PAGE_WRITE_SHIFT	(_PAGE_PRESENT_SHIFT + 1)
 #define _PAGE_WRITE		(1 << _PAGE_WRITE_SHIFT)
 /* implemented in software */
 #define _PAGE_ACCESSED_SHIFT	(_PAGE_WRITE_SHIFT + 1)
@@ -104,12 +101,12 @@
 #endif
 
 /* Page cannot be executed */
-#define _PAGE_NO_EXEC_SHIFT	(kernel_uses_smartmips_rixi ? _PAGE_HUGE_SHIFT + 1 : _PAGE_HUGE_SHIFT)
-#define _PAGE_NO_EXEC		({if (!kernel_uses_smartmips_rixi) BUG(); 1 << _PAGE_NO_EXEC_SHIFT; })
+#define _PAGE_NO_EXEC_SHIFT	(_PAGE_HUGE_SHIFT + 1)
+#define _PAGE_NO_EXEC		(1 << _PAGE_NO_EXEC_SHIFT)
 
 /* Page cannot be read */
-#define _PAGE_NO_READ_SHIFT	(kernel_uses_smartmips_rixi ? _PAGE_NO_EXEC_SHIFT + 1 : _PAGE_NO_EXEC_SHIFT)
-#define _PAGE_NO_READ		({if (!kernel_uses_smartmips_rixi) BUG(); 1 << _PAGE_NO_READ_SHIFT; })
+#define _PAGE_NO_READ_SHIFT	(_PAGE_NO_EXEC_SHIFT + 1)
+#define _PAGE_NO_READ		(1 << _PAGE_NO_READ_SHIFT)
 
 #define _PAGE_GLOBAL_SHIFT	(_PAGE_NO_READ_SHIFT + 1)
 #define _PAGE_GLOBAL		(1 << _PAGE_GLOBAL_SHIFT)
@@ -136,10 +133,6 @@
 #endif
 #define _PFN_MASK		(~((1 << (_PFN_SHIFT)) - 1))
 
-#ifndef _PAGE_NO_READ
-#define _PAGE_NO_READ ({BUG(); 0; })
-#define _PAGE_NO_READ_SHIFT ({BUG(); 0; })
-#endif
 #ifndef _PAGE_NO_EXEC
 #define _PAGE_NO_EXEC ({BUG(); 0; })
 #endif
@@ -220,7 +213,7 @@ static inline uint64_t pte_to_entrylo(unsigned long pte_val)
 
 #endif
 
-#define __READABLE	(_PAGE_SILENT_READ | _PAGE_ACCESSED | (kernel_uses_smartmips_rixi ? 0 : _PAGE_READ))
+#define __READABLE	(_PAGE_SILENT_READ | _PAGE_ACCESSED)
 #define __WRITEABLE	(_PAGE_WRITE | _PAGE_SILENT_WRITE | _PAGE_MODIFIED)
 
 #define _PAGE_CHG_MASK  (_PFN_MASK | _PAGE_ACCESSED | _PAGE_MODIFIED | _CACHE_MASK)
diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h
index 7e40f37..0b3e7c6 100644
--- a/arch/mips/include/asm/pgtable.h
+++ b/arch/mips/include/asm/pgtable.h
@@ -22,15 +22,15 @@ struct mm_struct;
 struct vm_area_struct;
 
 #define PAGE_NONE	__pgprot(_PAGE_PRESENT | _CACHE_CACHABLE_NONCOHERENT)
-#define PAGE_SHARED	__pgprot(_PAGE_PRESENT | _PAGE_WRITE | (kernel_uses_smartmips_rixi ? 0 : _PAGE_READ) | \
+#define PAGE_SHARED	__pgprot(_PAGE_PRESENT | _PAGE_WRITE | \
 				 _page_cachable_default)
-#define PAGE_COPY	__pgprot(_PAGE_PRESENT | (kernel_uses_smartmips_rixi ? 0 : _PAGE_READ) | \
-				 (kernel_uses_smartmips_rixi ?  _PAGE_NO_EXEC : 0) | _page_cachable_default)
-#define PAGE_READONLY	__pgprot(_PAGE_PRESENT | (kernel_uses_smartmips_rixi ? 0 : _PAGE_READ) | \
+#define PAGE_COPY	__pgprot(_PAGE_PRESENT | _PAGE_NO_EXEC | \
+				 _page_cachable_default)
+#define PAGE_READONLY	__pgprot(_PAGE_PRESENT | \
 				 _page_cachable_default)
 #define PAGE_KERNEL	__pgprot(_PAGE_PRESENT | __READABLE | __WRITEABLE | \
 				 _PAGE_GLOBAL | _page_cachable_default)
-#define PAGE_USERIO	__pgprot(_PAGE_PRESENT | (kernel_uses_smartmips_rixi ? 0 : _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)
@@ -250,7 +250,7 @@ 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_low  |= _PAGE_SILENT_READ;
 		pte.pte_high |= _PAGE_SILENT_READ;
 	}
@@ -299,13 +299,8 @@ static inline pte_t pte_mkdirty(pte_t pte)
 static inline pte_t pte_mkyoung(pte_t pte)
 {
 	pte_val(pte) |= _PAGE_ACCESSED;
-	if (kernel_uses_smartmips_rixi) {
-		if (!(pte_val(pte) & _PAGE_NO_READ))
-			pte_val(pte) |= _PAGE_SILENT_READ;
-	} else {
-		if (pte_val(pte) & _PAGE_READ)
-			pte_val(pte) |= _PAGE_SILENT_READ;
-	}
+	if (!(pte_val(pte) & _PAGE_NO_READ))
+		pte_val(pte) |= _PAGE_SILENT_READ;
 	return pte;
 }
 
diff --git a/arch/mips/mm/tlbex.c b/arch/mips/mm/tlbex.c
index f5734c2..451735b 100644
--- a/arch/mips/mm/tlbex.c
+++ b/arch/mips/mm/tlbex.c
@@ -1463,19 +1463,12 @@ static void __cpuinit
 build_pte_present(u32 **p, struct uasm_reloc **r,
 		  unsigned int pte, unsigned int ptr, enum label_id lid)
 {
-	if (kernel_uses_smartmips_rixi) {
-		if (use_bbit_insns()) {
-			uasm_il_bbit0(p, r, pte, ilog2(_PAGE_PRESENT), lid);
-			uasm_i_nop(p);
-		} else {
-			uasm_i_andi(p, pte, pte, _PAGE_PRESENT);
-			uasm_il_beqz(p, r, pte, lid);
-			iPTE_LW(p, pte, ptr);
-		}
+	if (use_bbit_insns()) {
+		uasm_il_bbit0(p, r, pte, ilog2(_PAGE_PRESENT), lid);
+		uasm_i_nop(p);
 	} else {
-		uasm_i_andi(p, pte, pte, _PAGE_PRESENT | _PAGE_READ);
-		uasm_i_xori(p, pte, pte, _PAGE_PRESENT | _PAGE_READ);
-		uasm_il_bnez(p, r, pte, lid);
+		uasm_i_andi(p, pte, pte, _PAGE_PRESENT);
+		uasm_il_beqz(p, r, pte, lid);
 		iPTE_LW(p, pte, ptr);
 	}
 }
-- 
1.7.4.3

[PATCH 2/4] MIPS: Add dummy _PAGE_NO_EXEC field for R3000 and 64BIT_PHYS_ADDR cases

[Kevin Cernekee]

Add a non-functional (software-only) _PAGE_NO_EXEC bit for all MIPS
pte layouts.  This allows for the elimination of the special case for
non-RIXI when initializing the page protection map.

Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
---
 arch/mips/include/asm/pgtable-bits.h |   21 ++++++-------
 arch/mips/mm/cache.c                 |   54 ++++++++++-----------------------
 2 files changed, 27 insertions(+), 48 deletions(-)

diff --git a/arch/mips/include/asm/pgtable-bits.h b/arch/mips/include/asm/pgtable-bits.h
index 7afba78..c83eaca 100644
--- a/arch/mips/include/asm/pgtable-bits.h
+++ b/arch/mips/include/asm/pgtable-bits.h
@@ -36,10 +36,11 @@
 
 #define _PAGE_PRESENT               (1<<6)  /* implemented in software */
 #define _PAGE_NO_READ               (1<<7)  /* implemented in software */
-#define _PAGE_WRITE                 (1<<8)  /* implemented in software */
-#define _PAGE_ACCESSED              (1<<9)  /* implemented in software */
-#define _PAGE_MODIFIED              (1<<10) /* implemented in software */
-#define _PAGE_FILE                  (1<<10) /* set:pagecache unset:swap */
+#define _PAGE_NO_EXEC               (1<<8)  /* implemented in software */
+#define _PAGE_WRITE                 (1<<9)  /* implemented in software */
+#define _PAGE_ACCESSED              (1<<10) /* implemented in software */
+#define _PAGE_MODIFIED              (1<<11) /* implemented in software */
+#define _PAGE_FILE                  (1<<11) /* set:pagecache unset:swap */
 
 #define _PAGE_R4KBUG                (1<<0)  /* workaround for r4k bug  */
 #define _PAGE_GLOBAL                (1<<0)
@@ -54,10 +55,11 @@
 
 #define _PAGE_PRESENT               (1<<0)  /* implemented in software */
 #define _PAGE_NO_READ               (1<<1)  /* implemented in software */
-#define _PAGE_WRITE                 (1<<2)  /* implemented in software */
-#define _PAGE_ACCESSED              (1<<3)  /* implemented in software */
-#define _PAGE_MODIFIED              (1<<4)  /* implemented in software */
-#define _PAGE_FILE                  (1<<4)  /* set:pagecache unset:swap */
+#define _PAGE_NO_EXEC               (1<<2)  /* implemented in software */
+#define _PAGE_WRITE                 (1<<3)  /* implemented in software */
+#define _PAGE_ACCESSED              (1<<4)  /* implemented in software */
+#define _PAGE_MODIFIED              (1<<5)  /* implemented in software */
+#define _PAGE_FILE                  (1<<5)  /* set:pagecache unset:swap */
 
 #define _PAGE_GLOBAL                (1<<8)
 #define _PAGE_VALID                 (1<<9)
@@ -133,9 +135,6 @@
 #endif
 #define _PFN_MASK		(~((1 << (_PFN_SHIFT)) - 1))
 
-#ifndef _PAGE_NO_EXEC
-#define _PAGE_NO_EXEC ({BUG(); 0; })
-#endif
 #ifndef _PAGE_GLOBAL_SHIFT
 #define _PAGE_GLOBAL_SHIFT ilog2(_PAGE_GLOBAL)
 #endif
diff --git a/arch/mips/mm/cache.c b/arch/mips/mm/cache.c
index 12af739..7c251e6 100644
--- a/arch/mips/mm/cache.c
+++ b/arch/mips/mm/cache.c
@@ -137,43 +137,23 @@ EXPORT_SYMBOL(_page_cachable_default);
 
 static inline void setup_protection_map(void)
 {
-	if (kernel_uses_smartmips_rixi) {
-		protection_map[0]  = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ);
-		protection_map[1]  = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC);
-		protection_map[2]  = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ);
-		protection_map[3]  = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC);
-		protection_map[4]  = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_READ);
-		protection_map[5]  = __pgprot(_page_cachable_default | _PAGE_PRESENT);
-		protection_map[6]  = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_READ);
-		protection_map[7]  = __pgprot(_page_cachable_default | _PAGE_PRESENT);
-
-		protection_map[8]  = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ);
-		protection_map[9]  = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC);
-		protection_map[10] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE | _PAGE_NO_READ);
-		protection_map[11] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE);
-		protection_map[12] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_READ);
-		protection_map[13] = __pgprot(_page_cachable_default | _PAGE_PRESENT);
-		protection_map[14] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_WRITE  | _PAGE_NO_READ);
-		protection_map[15] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_WRITE);
-
-	} else {
-		protection_map[0] = PAGE_NONE;
-		protection_map[1] = PAGE_READONLY;
-		protection_map[2] = PAGE_COPY;
-		protection_map[3] = PAGE_COPY;
-		protection_map[4] = PAGE_READONLY;
-		protection_map[5] = PAGE_READONLY;
-		protection_map[6] = PAGE_COPY;
-		protection_map[7] = PAGE_COPY;
-		protection_map[8] = PAGE_NONE;
-		protection_map[9] = PAGE_READONLY;
-		protection_map[10] = PAGE_SHARED;
-		protection_map[11] = PAGE_SHARED;
-		protection_map[12] = PAGE_READONLY;
-		protection_map[13] = PAGE_READONLY;
-		protection_map[14] = PAGE_SHARED;
-		protection_map[15] = PAGE_SHARED;
-	}
+	protection_map[0]  = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ);
+	protection_map[1]  = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC);
+	protection_map[2]  = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ);
+	protection_map[3]  = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC);
+	protection_map[4]  = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_READ);
+	protection_map[5]  = __pgprot(_page_cachable_default | _PAGE_PRESENT);
+	protection_map[6]  = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_READ);
+	protection_map[7]  = __pgprot(_page_cachable_default | _PAGE_PRESENT);
+
+	protection_map[8]  = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ);
+	protection_map[9]  = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC);
+	protection_map[10] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE | _PAGE_NO_READ);
+	protection_map[11] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE);
+	protection_map[12] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_READ);
+	protection_map[13] = __pgprot(_page_cachable_default | _PAGE_PRESENT);
+	protection_map[14] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_WRITE  | _PAGE_NO_READ);
+	protection_map[15] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_WRITE);
 }
 
 void __cpuinit cpu_cache_init(void)
-- 
1.7.4.3

Re: [PATCH 2/4] MIPS: Add dummy _PAGE_NO_EXEC field for R3000 and 64BIT_PHYS_ADDR cases

[Ralf Baechle]

Queued for 2.6.40.  Thanks Kevin!

  Ralf

[PATCH 3/4] MIPS: Clean up protection_map[] initialization

[Kevin Cernekee]

Fix long lines, factor out cut&paste flags, and add comments to explain
the pgprot flags used.

Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
---
 arch/mips/mm/cache.c |   42 +++++++++++++++++++++++++-----------------
 1 files changed, 25 insertions(+), 17 deletions(-)

diff --git a/arch/mips/mm/cache.c b/arch/mips/mm/cache.c
index 7c251e6..edb003f 100644
--- a/arch/mips/mm/cache.c
+++ b/arch/mips/mm/cache.c
@@ -137,23 +137,31 @@ EXPORT_SYMBOL(_page_cachable_default);
 
 static inline void setup_protection_map(void)
 {
-	protection_map[0]  = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ);
-	protection_map[1]  = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC);
-	protection_map[2]  = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ);
-	protection_map[3]  = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC);
-	protection_map[4]  = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_READ);
-	protection_map[5]  = __pgprot(_page_cachable_default | _PAGE_PRESENT);
-	protection_map[6]  = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_READ);
-	protection_map[7]  = __pgprot(_page_cachable_default | _PAGE_PRESENT);
-
-	protection_map[8]  = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ);
-	protection_map[9]  = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC);
-	protection_map[10] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE | _PAGE_NO_READ);
-	protection_map[11] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE);
-	protection_map[12] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_READ);
-	protection_map[13] = __pgprot(_page_cachable_default | _PAGE_PRESENT);
-	protection_map[14] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_WRITE  | _PAGE_NO_READ);
-	protection_map[15] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_WRITE);
+	int i;
+	const unsigned long prot[] = {
+		/* private mappings (clear the dirty bit until written) */
+		[0]	= _PAGE_NO_EXEC | _PAGE_NO_READ,	/* --- */
+		[1]	= _PAGE_NO_EXEC,			/* r-- */
+		[2]	= _PAGE_NO_EXEC | _PAGE_NO_READ,	/* -w- */
+		[3]	= _PAGE_NO_EXEC,			/* rw- */
+		[4]	= _PAGE_NO_READ,			/* --x */
+		[5]	= 0,					/* r-x */
+		[6]	= _PAGE_NO_READ,			/* -wx */
+		[7]	= 0,					/* rwx */
+		/* shared mappings */
+		[8]	= _PAGE_NO_EXEC | _PAGE_NO_READ,	/* --- */
+		[9]	= _PAGE_NO_EXEC,			/* r-- */
+		[10]	= _PAGE_NO_EXEC | _PAGE_WRITE | _PAGE_NO_READ, /* -w- */
+		[11]	= _PAGE_NO_EXEC | _PAGE_WRITE,		/* rw- */
+		[12]	= _PAGE_NO_READ,			/* --x */
+		[13]	= 0,					/* r-x */
+		[14]	= _PAGE_WRITE | _PAGE_NO_READ,		/* -wx */
+		[15]	= _PAGE_WRITE,				/* rwx */
+	};
+
+	for (i = 0; i < ARRAY_SIZE(protection_map); i++)
+		protection_map[i] = __pgprot(_page_cachable_default |
+					     _PAGE_PRESENT | prot[i]);
 }
 
 void __cpuinit cpu_cache_init(void)
-- 
1.7.4.3

Re: [PATCH 3/4] MIPS: Clean up protection_map[] initialization

[Ralf Baechle]

Queued for 2.6.40.  Thanks Kevin!

  Ralf

[PATCH 4/4] MIPS: Remove unused PAGE_* definitions

[Kevin Cernekee]

PAGE_{NONE,READONLY,COPY,SHARED} are no longer needed after refactoring
setup_protection_map() to explicitly list r/w/x permissions.

Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
---
 arch/mips/include/asm/pgtable.h |    7 -------
 1 files changed, 0 insertions(+), 7 deletions(-)

diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h
index 0b3e7c6..718991c 100644
--- a/arch/mips/include/asm/pgtable.h
+++ b/arch/mips/include/asm/pgtable.h
@@ -21,13 +21,6 @@
 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_cachable_default)
-#define PAGE_COPY	__pgprot(_PAGE_PRESENT | _PAGE_NO_EXEC | \
-				 _page_cachable_default)
-#define PAGE_READONLY	__pgprot(_PAGE_PRESENT | \
-				 _page_cachable_default)
 #define PAGE_KERNEL	__pgprot(_PAGE_PRESENT | __READABLE | __WRITEABLE | \
 				 _PAGE_GLOBAL | _page_cachable_default)
 #define PAGE_USERIO	__pgprot(_PAGE_PRESENT | _PAGE_WRITE | \
-- 
1.7.4.3

Re: [PATCH 4/4] MIPS: Remove unused PAGE_* definitions

[Ralf Baechle]

Queued for 2.6.40.  Thanks Kevin!

  Ralf

Re: [PATCH 1/4] MIPS: Replace _PAGE_READ with _PAGE_NO_READ

[David Daney]

On 04/16/2011 09:44 AM, Kevin Cernekee wrote:
> Reuse more of the same definitions for the non-RIXI and RIXI cases.  This
> avoids having special cases for kernel_uses_smartmips_rixi cluttering up
> the pgtable*.h files.
>
> On hardware that does not support RI/XI, EntryLo bits 31:30 / 63:62 will
> remain unset and RI/XI permissions will not be enforced.
>
> Signed-off-by: Kevin Cernekee<cernekee@gmail.com>
> ---
>   arch/mips/include/asm/pgtable-bits.h |   23 ++++++++---------------
>   arch/mips/include/asm/pgtable.h      |   21 ++++++++-------------
>   arch/mips/mm/tlbex.c                 |   17 +++++------------
>   3 files changed, 21 insertions(+), 40 deletions(-)
>
[...]

I like this patch.

How much testing have you done on non-RI/XI CPUs?

David Daney

Re: [PATCH 1/4] MIPS: Replace _PAGE_READ with _PAGE_NO_READ

[Kevin Cernekee]

On Mon, Apr 18, 2011 at 10:32 AM, David Daney <ddaney@caviumnetworks.com> wrote:
> How much testing have you done on non-RI/XI CPUs?

On a non-RIXI CPU I was able to boot the system, run a basic GUI
application, create R/W shared mappings to /dev/mem, insert/remove
kernel modules, run a broken program that dumps core, etc.

I guess it would be a good idea to make sure swap still works.  Didn't
try that yet.

Can you think of anything else that might exercise the bits that were
touched by the patch?  Were there any tests you ran during the
development of RIXI support which uncovered subtle issues?

Thanks.

Re: [PATCH 1/4] MIPS: Replace _PAGE_READ with _PAGE_NO_READ

[David Daney]

On 04/18/2011 11:24 AM, Kevin Cernekee wrote:
> On Mon, Apr 18, 2011 at 10:32 AM, David Daney<ddaney@caviumnetworks.com>  wrote:
>> How much testing have you done on non-RI/XI CPUs?
>
> On a non-RIXI CPU I was able to boot the system, run a basic GUI
> application, create R/W shared mappings to /dev/mem, insert/remove
> kernel modules, run a broken program that dumps core, etc.
>
> I guess it would be a good idea to make sure swap still works.  Didn't
> try that yet.
>
> Can you think of anything else that might exercise the bits that were
> touched by the patch?  Were there any tests you ran during the
> development of RIXI support which uncovered subtle issues?
>

We run the LTP, I think it tests these things.  We also have a small 
test case that tests for both the no-read and no-execute parts, but that 
would be expected to fail on platforms that don't have RI/XI bits.

David Daney

Re: [PATCH 1/4] MIPS: Replace _PAGE_READ with _PAGE_NO_READ

[Ralf Baechle]

Queued for 2.6.40.  Thanks Kevin!

  Ralf

Re: [PATCH 1/4] MIPS: Replace _PAGE_READ with _PAGE_NO_READ

[Ralf Baechle]

On Sat, Apr 16, 2011 at 09:44:29AM -0700, Kevin Cernekee wrote:

> Reuse more of the same definitions for the non-RIXI and RIXI cases.  This
> avoids having special cases for kernel_uses_smartmips_rixi cluttering up
> the pgtable*.h files.
> 
> On hardware that does not support RI/XI, EntryLo bits 31:30 / 63:62 will
> remain unset and RI/XI permissions will not be enforced.

Nice idea but it breaks on 64-bit hardware running 32-bit kernels.  On
those the RI/XI bits written to c0_entrylo0/1 31:30 will be interpreted as
physical address bits 37:36.

I'm removing this patch series from the 2.6.40 patch queue until we can
sort this out.

  Ralf

Re: [PATCH 1/4] MIPS: Replace _PAGE_READ with _PAGE_NO_READ

[Kevin Cernekee]

On Fri, May 13, 2011 at 8:07 AM, Ralf Baechle <ralf@linux-mips.org> wrote:
>> Reuse more of the same definitions for the non-RIXI and RIXI cases.  This
>> avoids having special cases for kernel_uses_smartmips_rixi cluttering up
>> the pgtable*.h files.
>>
>> On hardware that does not support RI/XI, EntryLo bits 31:30 / 63:62 will
>> remain unset and RI/XI permissions will not be enforced.
>
> Nice idea but it breaks on 64-bit hardware running 32-bit kernels.  On
> those the RI/XI bits written to c0_entrylo0/1 31:30 will be interpreted as
> physical address bits 37:36.

Hmm, are you sure?  (Unfortunately I do not have a 64-bit machine to
test it on.)

I did not touch David's existing build_update_entries(), which makes a
point not to set the RI/XI bits when the RIXI feature is disabled:

        if (kernel_uses_smartmips_rixi) {
                UASM_i_SRL(p, tmp, tmp, ilog2(_PAGE_NO_EXEC));
                UASM_i_SRL(p, ptep, ptep, ilog2(_PAGE_NO_EXEC));
                UASM_i_ROTR(p, tmp, tmp, ilog2(_PAGE_GLOBAL) -
ilog2(_PAGE_NO_EXEC));
                if (r4k_250MHZhwbug())
                        UASM_i_MTC0(p, 0, C0_ENTRYLO0);
                UASM_i_MTC0(p, tmp, C0_ENTRYLO0); /* load it */
                UASM_i_ROTR(p, ptep, ptep, ilog2(_PAGE_GLOBAL) -
ilog2(_PAGE_NO_EXEC));
        } else {
                UASM_i_SRL(p, tmp, tmp, ilog2(_PAGE_GLOBAL)); /*
convert to entrylo0 */
                if (r4k_250MHZhwbug())
                        UASM_i_MTC0(p, 0, C0_ENTRYLO0);
                UASM_i_MTC0(p, tmp, C0_ENTRYLO0); /* load it */
                UASM_i_SRL(p, ptep, ptep, ilog2(_PAGE_GLOBAL)); /*
convert to entrylo1 */
                if (r45k_bvahwbug())
                        uasm_i_mfc0(p, tmp, C0_INDEX);
        }

If RIXI is enabled, it shifts the SW bits off the end of the register,
then rotates the RI/XI bits into place.

If RIXI is disabled, it shifts the SW bits + RI/XI bits off the end of
the register.  It should not be setting bits 31:30 or 63:62, ever.

(A side issue here is that ROTR is a MIPS R2 instruction, so we could
never remove the old handler and use the RIXI version of the TLB
handler on an R1 machine.)

If setting EntryLo bits 31:30 for RI/XI is illegal on a 64-bit system
running a 32-bit kernel, I suspect we will have a problem with the
existing RIXI TLB update code, regardless of whether my changes are
applied.

Re: [PATCH 1/4] MIPS: Replace _PAGE_READ with _PAGE_NO_READ

[Ralf Baechle]

On Fri, May 13, 2011 at 08:46:18AM -0700, Kevin Cernekee wrote:

> >> On hardware that does not support RI/XI, EntryLo bits 31:30 / 63:62 will
> >> remain unset and RI/XI permissions will not be enforced.
> >
> > Nice idea but it breaks on 64-bit hardware running 32-bit kernels.  On
> > those the RI/XI bits written to c0_entrylo0/1 31:30 will be interpreted as
> > physical address bits 37:36.
> 
> Hmm, are you sure?  (Unfortunately I do not have a 64-bit machine to
> test it on.)
> 
> I did not touch David's existing build_update_entries(), which makes a
> point not to set the RI/XI bits when the RIXI feature is disabled:
> 
>         if (kernel_uses_smartmips_rixi) {
>                 UASM_i_SRL(p, tmp, tmp, ilog2(_PAGE_NO_EXEC));
>                 UASM_i_SRL(p, ptep, ptep, ilog2(_PAGE_NO_EXEC));
>                 UASM_i_ROTR(p, tmp, tmp, ilog2(_PAGE_GLOBAL) -
> ilog2(_PAGE_NO_EXEC));
>                 if (r4k_250MHZhwbug())
>                         UASM_i_MTC0(p, 0, C0_ENTRYLO0);
>                 UASM_i_MTC0(p, tmp, C0_ENTRYLO0); /* load it */
>                 UASM_i_ROTR(p, ptep, ptep, ilog2(_PAGE_GLOBAL) -
> ilog2(_PAGE_NO_EXEC));
>         } else {
>                 UASM_i_SRL(p, tmp, tmp, ilog2(_PAGE_GLOBAL)); /*
> convert to entrylo0 */
>                 if (r4k_250MHZhwbug())
>                         UASM_i_MTC0(p, 0, C0_ENTRYLO0);
>                 UASM_i_MTC0(p, tmp, C0_ENTRYLO0); /* load it */
>                 UASM_i_SRL(p, ptep, ptep, ilog2(_PAGE_GLOBAL)); /*
> convert to entrylo1 */
>                 if (r45k_bvahwbug())
>                         uasm_i_mfc0(p, tmp, C0_INDEX);
>         }
> 
> If RIXI is enabled, it shifts the SW bits off the end of the register,
> then rotates the RI/XI bits into place.
> 
> If RIXI is disabled, it shifts the SW bits + RI/XI bits off the end of
> the register.  It should not be setting bits 31:30 or 63:62, ever.
> 
> (A side issue here is that ROTR is a MIPS R2 instruction, so we could
> never remove the old handler and use the RIXI version of the TLB
> handler on an R1 machine.)
> 
> If setting EntryLo bits 31:30 for RI/XI is illegal on a 64-bit system
> running a 32-bit kernel, I suspect we will have a problem with the
> existing RIXI TLB update code, regardless of whether my changes are
> applied.

I'm not totally certain with my explanation but it seemed like a good
working hypothesis.  Jayachandran C. bisected this morning's linux-queue
on his Netlogic XLR which is MIPS64 R1 and found this comment causing
the problem.

  Ralf

Re: [PATCH 1/4] MIPS: Replace _PAGE_READ with _PAGE_NO_READ

[Kevin Cernekee]

On Fri, May 13, 2011 at 8:56 AM, Ralf Baechle <ralf@linux-mips.org> wrote:
> I'm not totally certain with my explanation but it seemed like a good
> working hypothesis.  Jayachandran C. bisected this morning's linux-queue
> on his Netlogic XLR which is MIPS64 R1 and found this comment causing
> the problem.

Jayachandran, could you please confirm/deny the following:

Netlogic XLR is a MIPS64 R1 system.

You are running a 32-bit kernel.

You are using 64-bit physical addresses.

You are not enabling RI/XI.

The commit that caused the regression was "[PATCH 1/4] MIPS: Replace
_PAGE_READ with _PAGE_NO_READ" (not 2/4, 3/4, or 4/4).

Do you have a log showing the failure, or any other details of what happened?

Thanks.

Re: [PATCH 1/4] MIPS: Replace _PAGE_READ with _PAGE_NO_READ

[Jayachandran C.]

On Fri, May 13, 2011 at 09:55:21AM -0700, Kevin Cernekee wrote:
> On Fri, May 13, 2011 at 8:56 AM, Ralf Baechle <ralf@linux-mips.org> wrote:
> > I'm not totally certain with my explanation but it seemed like a good
> > working hypothesis.  Jayachandran C. bisected this morning's linux-queue
> > on his Netlogic XLR which is MIPS64 R1 and found this comment causing
> > the problem.
> 
> Jayachandran, could you please confirm/deny the following:
> 
> Netlogic XLR is a MIPS64 R1 system.
> 
> You are running a 32-bit kernel.
> 
> You are using 64-bit physical addresses.
> 
> You are not enabling RI/XI.
> 
> The commit that caused the regression was "[PATCH 1/4] MIPS: Replace
> _PAGE_READ with _PAGE_NO_READ" (not 2/4, 3/4, or 4/4).
> 
> Do you have a log showing the failure, or any other details of what happened?

Yes, it is a MIPS64R1 system with 64-bit (well 40bit) physical address, we
don't have rixi either on hardware on in kernel overrides. git bisect pointed
the specific patch.

And with your patch it works only on 64 bit compile, 32 bit kernel fails on
init with:
|malloc: subst.c:521: assertion botched
|free: called with already freed block argument

For 32-bit the config is nlm_xlr_defconfig in the source tree. Let me know if
you need any further info.

Regards,
JC.

Re: [PATCH 1/4] MIPS: Replace _PAGE_READ with _PAGE_NO_READ

[Kevin Cernekee]

On Fri, May 13, 2011 at 10:36 AM, Jayachandran C.
<jayachandranc@netlogicmicro.com> wrote:
> For 32-bit the config is nlm_xlr_defconfig in the source tree. Let me know if
> you need any further info.

Would you be able to dump out the TLB handlers in this configuration,
per David's suggestion?

Thanks.

Re: [PATCH 1/4] MIPS: Replace _PAGE_READ with _PAGE_NO_READ

[Jayachandran C.]

On Fri, May 13, 2011 at 10:51:44AM -0700, Kevin Cernekee wrote:
> On Fri, May 13, 2011 at 10:36 AM, Jayachandran C.
> <jayachandranc@netlogicmicro.com> wrote:
> > For 32-bit the config is nlm_xlr_defconfig in the source tree. Let me know if
> > you need any further info.
> 
> Would you be able to dump out the TLB handlers in this configuration,
> per David's suggestion?

The current linux-mips queue works for me, and I don't have the old source
or binaries with me anymore. You surely should be able build with
nlm_xlr_defconfig and see if the rixi is enabled in the build, if you want
any config register dump on the CPU, please let me know.

JC.

Re: [PATCH 1/4] MIPS: Replace _PAGE_READ with _PAGE_NO_READ

[David Daney]

On 05/13/2011 11:45 AM, Jayachandran C. wrote:
> On Fri, May 13, 2011 at 10:51:44AM -0700, Kevin Cernekee wrote:
>> On Fri, May 13, 2011 at 10:36 AM, Jayachandran C.
>> <jayachandranc@netlogicmicro.com>  wrote:
>>> For 32-bit the config is nlm_xlr_defconfig in the source tree. Let me know if
>>> you need any further info.
>>
>> Would you be able to dump out the TLB handlers in this configuration,
>> per David's suggestion?
>
> The current linux-mips queue works for me, and I don't have the old source
> or binaries with me anymore. You surely should be able build with
> nlm_xlr_defconfig and see if the rixi is enabled in the build, if you want
> any config register dump on the CPU, please let me know.

The problem is that we don't have your hardware to test anything on.

Kevin's patches are a good cleanup, but we cannot use them if they break 
things.  So the ideal situation would be for people maintaining the 
failing ports to help figure out where they fail.

David Daney

Re: [PATCH 1/4] MIPS: Replace _PAGE_READ with _PAGE_NO_READ

[Arnaud Patard]

d

Re: [PATCH 1/4] MIPS: Replace _PAGE_READ with _PAGE_NO_READ

[Kevin Cernekee]

On Fri, May 13, 2011 at 11:45 AM, Jayachandran C.
<jayachandranc@netlogicmicro.com> wrote:
> The current linux-mips queue works for me, and I don't have the old source
> or binaries with me anymore. You surely should be able build with
> nlm_xlr_defconfig and see if the rixi is enabled in the build, if you want
> any config register dump on the CPU, please let me know.

I was able to locate an old MIPS R5000 based system and get linux-mips
queue running on it.  Here are the settings:

CONFIG_ARCH_DMA_ADDR_T_64BIT=y
CONFIG_64BIT_PHYS_ADDR=y
CONFIG_ARCH_PHYS_ADDR_T_64BIT=y
CONFIG_PHYS_ADDR_T_64BIT=y
CONFIG_SYS_SUPPORTS_32BIT_KERNEL=y
CONFIG_CPU_SUPPORTS_32BIT_KERNEL=y
CONFIG_SYS_SUPPORTS_64BIT_KERNEL=y
CONFIG_CPU_SUPPORTS_64BIT_KERNEL=y
CONFIG_32BIT=y
# CONFIG_64BIT is not set
CONFIG_SMP=y

This was intended to mimic the XLR configuration: 32-bit kernel on a
64-bit CPU with 64-bit physical addressing, SMP (albeit with 1 CPU),
no RI/XI.

After applying all 4 of my page cleanup patches, the system still
booted and ran normally.

Userspace is glibc with a bash shell (also tried uClibc w/bash, same
result).  Since the reported assertion appeared to be in bash.

Jayachandran - how do you think we should debug this?  It seems like
the problem only shows up on XLR.  Since this is a relatively new
platform, is it possible that something else might be broken still?

FWIW, here are the TLB handlers:

Refill:

    80000000:   401b2000        mfc0    k1,c0_context
    80000004:   3c1a80a5        lui     k0,0x80a5
    80000008:   001bddc2        srl     k1,k1,0x17
    8000000c:   035bd821        addu    k1,k0,k1
    80000010:   401a4000        mfc0    k0,c0_badvaddr
    80000014:   8f7b4000        lw      k1,16384(k1)
    80000018:   001ad542        srl     k0,k0,0x15
    8000001c:   001ad080        sll     k0,k0,0x2
    80000020:   037ad821        addu    k1,k1,k0
    80000024:   401a2000        mfc0    k0,c0_context
    80000028:   8f7b0000        lw      k1,0(k1)
    8000002c:   335a0ff0        andi    k0,k0,0xff0
    80000030:   037ad821        addu    k1,k1,k0
    80000034:   df7a0000        ld      k0,0(k1)
    80000038:   df7b0008        ld      k1,8(k1)
    8000003c:   001ad1ba        dsrl    k0,k0,0x6
    80000040:   409a1000        mtc0    k0,c0_entrylo0
    80000044:   001bd9ba        dsrl    k1,k1,0x6
    80000048:   409b1800        mtc0    k1,c0_entrylo1
    8000004c:   00000000        nop
    80000050:   42000006        tlbwr
    80000054:   42000018        eret

Load:

    801fe000:   401b2000        mfc0    k1,c0_context
    801fe004:   3c1a80a5        lui     k0,0x80a5
    801fe008:   001bddc2        srl     k1,k1,0x17
    801fe00c:   035bd821        addu    k1,k0,k1
    801fe010:   401a4000        mfc0    k0,c0_badvaddr
    801fe014:   8f7b4000        lw      k1,16384(k1)
    801fe018:   001ad542        srl     k0,k0,0x15
    801fe01c:   001ad080        sll     k0,k0,0x2
    801fe020:   037ad821        addu    k1,k1,k0
    801fe024:   401a4000        mfc0    k0,c0_badvaddr
    801fe028:   8f7b0000        lw      k1,0(k1)
    801fe02c:   001ad242        srl     k0,k0,0x9
    801fe030:   335a0ff8        andi    k0,k0,0xff8
    801fe034:   037ad821        addu    k1,k1,k0
    801fe038:   d37a0000        lld     k0,0(k1)
    801fe03c:   42000008        tlbp
    801fe040:   335a0001        andi    k0,k0,0x1
    801fe044:   13400010        beqz    k0,0x801fe088
    801fe048:   d37a0000        lld     k0,0(k1)
    801fe04c:   375a0084        ori     k0,k0,0x84
    801fe050:   f37a0000        scd     k0,0(k1)
    801fe054:   1340fff8        beqz    k0,0x801fe038
    801fe058:   00000000        nop
    801fe05c:   377b0008        ori     k1,k1,0x8
    801fe060:   3b7b0008        xori    k1,k1,0x8
    801fe064:   df7a0000        ld      k0,0(k1)
    801fe068:   df7b0008        ld      k1,8(k1)
    801fe06c:   001ad1ba        dsrl    k0,k0,0x6
    801fe070:   409a1000        mtc0    k0,c0_entrylo0
    801fe074:   001bd9ba        dsrl    k1,k1,0x6
    801fe078:   409b1800        mtc0    k1,c0_entrylo1
    801fe07c:   00000000        nop
    801fe080:   42000002        tlbwi
    801fe084:   42000018        eret
    801fe088:   080036d8        j       0x8000db60
    801fe08c:   00000000        nop

Store:

    801fe200:   401b2000        mfc0    k1,c0_context
    801fe204:   3c1a80a5        lui     k0,0x80a5
    801fe208:   001bddc2        srl     k1,k1,0x17
    801fe20c:   035bd821        addu    k1,k0,k1
    801fe210:   401a4000        mfc0    k0,c0_badvaddr
    801fe214:   8f7b4000        lw      k1,16384(k1)
    801fe218:   001ad542        srl     k0,k0,0x15
    801fe21c:   001ad080        sll     k0,k0,0x2
    801fe220:   037ad821        addu    k1,k1,k0
    801fe224:   401a4000        mfc0    k0,c0_badvaddr
    801fe228:   8f7b0000        lw      k1,0(k1)
    801fe22c:   001ad242        srl     k0,k0,0x9
    801fe230:   335a0ff8        andi    k0,k0,0xff8
    801fe234:   037ad821        addu    k1,k1,k0
    801fe238:   d37a0000        lld     k0,0(k1)
    801fe23c:   42000008        tlbp
    801fe240:   335a0003        andi    k0,k0,0x3
    801fe244:   3b5a0003        xori    k0,k0,0x3
    801fe248:   17400010        bnez    k0,0x801fe28c
    801fe24c:   d37a0000        lld     k0,0(k1)
    801fe250:   375a018c        ori     k0,k0,0x18c
    801fe254:   f37a0000        scd     k0,0(k1)
    801fe258:   1340fff7        beqz    k0,0x801fe238
    801fe25c:   00000000        nop
    801fe260:   377b0008        ori     k1,k1,0x8
    801fe264:   3b7b0008        xori    k1,k1,0x8
    801fe268:   df7a0000        ld      k0,0(k1)
    801fe26c:   df7b0008        ld      k1,8(k1)
    801fe270:   001ad1ba        dsrl    k0,k0,0x6
    801fe274:   409a1000        mtc0    k0,c0_entrylo0
    801fe278:   001bd9ba        dsrl    k1,k1,0x6
    801fe27c:   409b1800        mtc0    k1,c0_entrylo1
    801fe280:   00000000        nop
    801fe284:   42000002        tlbwi
    801fe288:   42000018        eret
    801fe28c:   0800371d        j       0x8000dc74
    801fe290:   00000000        nop

Modify:

    801fe400:   401b2000        mfc0    k1,c0_context
    801fe404:   3c1a80a5        lui     k0,0x80a5
    801fe408:   001bddc2        srl     k1,k1,0x17
    801fe40c:   035bd821        addu    k1,k0,k1
    801fe410:   401a4000        mfc0    k0,c0_badvaddr
    801fe414:   8f7b4000        lw      k1,16384(k1)
    801fe418:   001ad542        srl     k0,k0,0x15
    801fe41c:   001ad080        sll     k0,k0,0x2
    801fe420:   037ad821        addu    k1,k1,k0
    801fe424:   401a4000        mfc0    k0,c0_badvaddr
    801fe428:   8f7b0000        lw      k1,0(k1)
    801fe42c:   001ad242        srl     k0,k0,0x9
    801fe430:   335a0ff8        andi    k0,k0,0xff8
    801fe434:   037ad821        addu    k1,k1,k0
    801fe438:   d37a0000        lld     k0,0(k1)
    801fe43c:   42000008        tlbp
    801fe440:   335a0002        andi    k0,k0,0x2
    801fe444:   13400010        beqz    k0,0x801fe488
    801fe448:   d37a0000        lld     k0,0(k1)
    801fe44c:   375a018c        ori     k0,k0,0x18c
    801fe450:   f37a0000        scd     k0,0(k1)
    801fe454:   1340fff8        beqz    k0,0x801fe438
    801fe458:   00000000        nop
    801fe45c:   377b0008        ori     k1,k1,0x8
    801fe460:   3b7b0008        xori    k1,k1,0x8
    801fe464:   df7a0000        ld      k0,0(k1)
    801fe468:   df7b0008        ld      k1,8(k1)
    801fe46c:   001ad1ba        dsrl    k0,k0,0x6
    801fe470:   409a1000        mtc0    k0,c0_entrylo0
    801fe474:   001bd9ba        dsrl    k1,k1,0x6
    801fe478:   409b1800        mtc0    k1,c0_entrylo1
    801fe47c:   00000000        nop
    801fe480:   42000002        tlbwi
    801fe484:   42000018        eret
    801fe488:   0800371d        j       0x8000dc74
    801fe48c:   00000000        nop

Re: [PATCH 1/4] MIPS: Replace _PAGE_READ with _PAGE_NO_READ

[Jayachandran C.]

On Fri, May 13, 2011 at 03:06:35PM -0700, Kevin Cernekee wrote:
> On Fri, May 13, 2011 at 11:45 AM, Jayachandran C.
> <jayachandranc@netlogicmicro.com> wrote:
> > The current linux-mips queue works for me, and I don't have the old source
> > or binaries with me anymore. You surely should be able build with
> > nlm_xlr_defconfig and see if the rixi is enabled in the build, if you want
> > any config register dump on the CPU, please let me know.
> 
> I was able to locate an old MIPS R5000 based system and get linux-mips
> queue running on it.  Here are the settings:
> 
> CONFIG_ARCH_DMA_ADDR_T_64BIT=y
> CONFIG_64BIT_PHYS_ADDR=y
> CONFIG_ARCH_PHYS_ADDR_T_64BIT=y
> CONFIG_PHYS_ADDR_T_64BIT=y
> CONFIG_SYS_SUPPORTS_32BIT_KERNEL=y
> CONFIG_CPU_SUPPORTS_32BIT_KERNEL=y
> CONFIG_SYS_SUPPORTS_64BIT_KERNEL=y
> CONFIG_CPU_SUPPORTS_64BIT_KERNEL=y
> CONFIG_32BIT=y
> # CONFIG_64BIT is not set
> CONFIG_SMP=y
> 
> This was intended to mimic the XLR configuration: 32-bit kernel on a
> 64-bit CPU with 64-bit physical addressing, SMP (albeit with 1 CPU),
> no RI/XI.
> 
> After applying all 4 of my page cleanup patches, the system still
> booted and ran normally.
> 
> Userspace is glibc with a bash shell (also tried uClibc w/bash, same
> result).  Since the reported assertion appeared to be in bash.
> 
> Jayachandran - how do you think we should debug this?  It seems like
> the problem only shows up on XLR.  Since this is a relatively new
> platform, is it possible that something else might be broken still?

Can you send me the patchset which works on top of queue with any
debugging you want enabled?  I can try that and send you the results.

It is also possible that something is broken with the XLR platform code,
it is currently almost straight r4k...

Thanks,
JC.

Re: [PATCH 1/4] MIPS: Replace _PAGE_READ with _PAGE_NO_READ

[Kevin Cernekee]

On Fri, May 13, 2011 at 10:13 PM, Jayachandran C.
<jayachandranc@netlogicmicro.com> wrote:
> Can you send me the patchset which works on top of queue with any
> debugging you want enabled?  I can try that and send you the results.
>
> It is also possible that something is broken with the XLR platform code,
> it is currently almost straight r4k...

Well, David suggested adding "#define DEBUG 1" at the very top of
tlbex.c, then booting with "debug" and posting the TLB refill handler
to make sure the RI/XI code isn't getting enabled.  That seems like a
reasonable start.  Even if there's no smoking gun, we'd still be able
to compare our TLB handlers side-by-side.

Personally I don't have any other leads or patches to try.  These
changes work fine for me in every configuration I am able to test:

32-bit MIPS32 system, 32-bit kernel (non-RIXI)
32-bit MIPS32 system, 32-bit kernel (XI)
64-bit R5000 system, 32-bit kernel (non-RIXI, with 64-bit physical addresses)
64-bit R5000 system, 64-bit kernel (non-RIXI)

So it's really best for somebody to debug the problem hands-on, on the
system that showed the issue.

Would you be able to post your rootfs image?  Are you using
"usr/dev_file_list usr/rootfs" from CONFIG_INITRAMFS_SOURCE?  That
could eliminate one other potential difference between our
configurations.

Re: [PATCH 1/4] MIPS: Replace _PAGE_READ with _PAGE_NO_READ

[David Daney]

On 05/13/2011 08:56 AM, Ralf Baechle wrote:
> On Fri, May 13, 2011 at 08:46:18AM -0700, Kevin Cernekee wrote:
>
>>>> On hardware that does not support RI/XI, EntryLo bits 31:30 / 63:62 will
>>>> remain unset and RI/XI permissions will not be enforced.
>>>
>>> Nice idea but it breaks on 64-bit hardware running 32-bit kernels.  On
>>> those the RI/XI bits written to c0_entrylo0/1 31:30 will be interpreted as
>>> physical address bits 37:36.
>>
>> Hmm, are you sure?  (Unfortunately I do not have a 64-bit machine to
>> test it on.)
>>
>> I did not touch David's existing build_update_entries(), which makes a
>> point not to set the RI/XI bits when the RIXI feature is disabled:
>>
>>          if (kernel_uses_smartmips_rixi) {
>>                  UASM_i_SRL(p, tmp, tmp, ilog2(_PAGE_NO_EXEC));
>>                  UASM_i_SRL(p, ptep, ptep, ilog2(_PAGE_NO_EXEC));
>>                  UASM_i_ROTR(p, tmp, tmp, ilog2(_PAGE_GLOBAL) -
>> ilog2(_PAGE_NO_EXEC));
>>                  if (r4k_250MHZhwbug())
>>                          UASM_i_MTC0(p, 0, C0_ENTRYLO0);
>>                  UASM_i_MTC0(p, tmp, C0_ENTRYLO0); /* load it */
>>                  UASM_i_ROTR(p, ptep, ptep, ilog2(_PAGE_GLOBAL) -
>> ilog2(_PAGE_NO_EXEC));
>>          } else {
>>                  UASM_i_SRL(p, tmp, tmp, ilog2(_PAGE_GLOBAL)); /*
>> convert to entrylo0 */
>>                  if (r4k_250MHZhwbug())
>>                          UASM_i_MTC0(p, 0, C0_ENTRYLO0);
>>                  UASM_i_MTC0(p, tmp, C0_ENTRYLO0); /* load it */
>>                  UASM_i_SRL(p, ptep, ptep, ilog2(_PAGE_GLOBAL)); /*
>> convert to entrylo1 */
>>                  if (r45k_bvahwbug())
>>                          uasm_i_mfc0(p, tmp, C0_INDEX);
>>          }
>>
>> If RIXI is enabled, it shifts the SW bits off the end of the register,
>> then rotates the RI/XI bits into place.
>>
>> If RIXI is disabled, it shifts the SW bits + RI/XI bits off the end of
>> the register.  It should not be setting bits 31:30 or 63:62, ever.
>>
>> (A side issue here is that ROTR is a MIPS R2 instruction, so we could
>> never remove the old handler and use the RIXI version of the TLB
>> handler on an R1 machine.)
>>
>> If setting EntryLo bits 31:30 for RI/XI is illegal on a 64-bit system
>> running a 32-bit kernel, I suspect we will have a problem with the
>> existing RIXI TLB update code, regardless of whether my changes are
>> applied.
>
> I'm not totally certain with my explanation but it seemed like a good
> working hypothesis.  Jayachandran C. bisected this morning's linux-queue
> on his Netlogic XLR which is MIPS64 R1 and found this comment causing
> the problem.

He should dump out the TLB Refill handler with the patch set applied. 
Perhaps it is erroneously getting in RI/XI mode.

Put #define DEBUG 1 as the first line of tlbex.c, then boot the kernel 
with 'debug' on the command line.  Also it is best to have early printk 
enabled so you can see the dump.

David Daney.