[ARM] Set bit 4 on section mappings correctly depending on CPU

On some CPUs, bit 4 of section mappings means "update the
cache when written to".  On others, this bit is required to
be one, and others it's required to be zero.  Finally, on
ARMv6 and above, setting it turns on "no execute" and prevents
speculative prefetches.

With all these combinations, no one value fits all CPUs, so we
have to pick a value depending on the CPU type, and the area
we're mapping.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/kernel/asm-offsets.c

@@ -105,6 +105,7 @@ int main(void)
   BLANK();
   DEFINE(PROC_INFO_SZ,		sizeof(struct proc_info_list));
   DEFINE(PROCINFO_INITFUNC,	offsetof(struct proc_info_list, __cpu_flush));
-  DEFINE(PROCINFO_MMUFLAGS,	offsetof(struct proc_info_list, __cpu_mmu_flags));
+  DEFINE(PROCINFO_MM_MMUFLAGS,	offsetof(struct proc_info_list, __cpu_mm_mmu_flags));
+  DEFINE(PROCINFO_IO_MMUFLAGS,	offsetof(struct proc_info_list, __cpu_io_mmu_flags));
   return 0; 
 }

arch/arm/kernel/head.S

@@ -221,7 +221,7 @@ __create_page_tables:
 	teq	r0, r6
 	bne	1b
 
-	ldr	r7, [r10, #PROCINFO_MMUFLAGS]	@ mmuflags
+	ldr	r7, [r10, #PROCINFO_MM_MMUFLAGS] @ mm_mmuflags
 
 	/*
 	 * Create identity mapping for first MB of kernel to
@@ -272,8 +272,7 @@ __create_page_tables:
 #endif
 
 #ifdef CONFIG_DEBUG_LL
-	bic	r7, r7, #0x0c			@ turn off cacheable
-						@ and bufferable bits
+	ldr	r7, [r10, #PROCINFO_IO_MMUFLAGS] @ io_mmuflags
 	/*
 	 * Map in IO space for serial debugging.
 	 * This allows debug messages to be output

arch/arm/mm/mm-armv.c

@@ -303,16 +303,16 @@ static struct mem_types mem_types[] __initdata = {
 		.prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
 				L_PTE_WRITE,
 		.prot_l1   = PMD_TYPE_TABLE,
-		.prot_sect = PMD_TYPE_SECT | PMD_SECT_UNCACHED |
+		.prot_sect = PMD_TYPE_SECT | PMD_BIT4 | PMD_SECT_UNCACHED |
 				PMD_SECT_AP_WRITE,
 		.domain    = DOMAIN_IO,
 	},
 	[MT_CACHECLEAN] = {
-		.prot_sect = PMD_TYPE_SECT,
+		.prot_sect = PMD_TYPE_SECT | PMD_BIT4,
 		.domain    = DOMAIN_KERNEL,
 	},
 	[MT_MINICLEAN] = {
-		.prot_sect = PMD_TYPE_SECT | PMD_SECT_MINICACHE,
+		.prot_sect = PMD_TYPE_SECT | PMD_BIT4 | PMD_SECT_MINICACHE,
 		.domain    = DOMAIN_KERNEL,
 	},
 	[MT_LOW_VECTORS] = {
@@ -328,25 +328,25 @@ static struct mem_types mem_types[] __initdata = {
 		.domain    = DOMAIN_USER,
 	},
 	[MT_MEMORY] = {
-		.prot_sect = PMD_TYPE_SECT | PMD_SECT_AP_WRITE,
+		.prot_sect = PMD_TYPE_SECT | PMD_BIT4 | PMD_SECT_AP_WRITE,
 		.domain    = DOMAIN_KERNEL,
 	},
 	[MT_ROM] = {
-		.prot_sect = PMD_TYPE_SECT,
+		.prot_sect = PMD_TYPE_SECT | PMD_BIT4,
 		.domain    = DOMAIN_KERNEL,
 	},
 	[MT_IXP2000_DEVICE] = { /* IXP2400 requires XCB=101 for on-chip I/O */
 		.prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
 				L_PTE_WRITE,
 		.prot_l1   = PMD_TYPE_TABLE,
-		.prot_sect = PMD_TYPE_SECT | PMD_SECT_UNCACHED |
+		.prot_sect = PMD_TYPE_SECT | PMD_BIT4 | PMD_SECT_UNCACHED |
 				PMD_SECT_AP_WRITE | PMD_SECT_BUFFERABLE |
 				PMD_SECT_TEX(1),
 		.domain    = DOMAIN_IO,
 	},
 	[MT_NONSHARED_DEVICE] = {
 		.prot_l1   = PMD_TYPE_TABLE,
-		.prot_sect = PMD_TYPE_SECT | PMD_SECT_NONSHARED_DEV |
+		.prot_sect = PMD_TYPE_SECT | PMD_BIT4 | PMD_SECT_NONSHARED_DEV |
 				PMD_SECT_AP_WRITE,
 		.domain    = DOMAIN_IO,
 	}
@@ -376,14 +376,21 @@ void __init build_mem_type_table(void)
 		ecc_mask = 0;
 	}
 
-	if (cpu_arch <= CPU_ARCH_ARMv5TEJ && !cpu_is_xscale()) {
-		for (i = 0; i < ARRAY_SIZE(mem_types); i++) {
+	/*
+	 * Xscale must not have PMD bit 4 set for section mappings.
+	 */
+	if (cpu_is_xscale())
+		for (i = 0; i < ARRAY_SIZE(mem_types); i++)
+			mem_types[i].prot_sect &= ~PMD_BIT4;
+
+	/*
+	 * ARMv5 and lower, excluding Xscale, bit 4 must be set for
+	 * page tables.
+	 */
+	if (cpu_arch < CPU_ARCH_ARMv6 && !cpu_is_xscale())
+		for (i = 0; i < ARRAY_SIZE(mem_types); i++)
 			if (mem_types[i].prot_l1)
 				mem_types[i].prot_l1 |= PMD_BIT4;
-			if (mem_types[i].prot_sect)
-				mem_types[i].prot_sect |= PMD_BIT4;
-		}
-	}
 
 	cp = &cache_policies[cachepolicy];
 	kern_pgprot = user_pgprot = cp->pte;
@@ -407,8 +414,8 @@ void __init build_mem_type_table(void)
 		 * bit 4 becomes XN which we must clear for the
 		 * kernel memory mapping.
 		 */
-		mem_types[MT_MEMORY].prot_sect &= ~PMD_BIT4;
-		mem_types[MT_ROM].prot_sect &= ~PMD_BIT4;
+		mem_types[MT_MEMORY].prot_sect &= ~PMD_SECT_XN;
+		mem_types[MT_ROM].prot_sect &= ~PMD_SECT_XN;
 
 		/*
 		 * Mark cache clean areas and XIP ROM read only

arch/arm/mm/proc-arm1020.S

@@ -524,6 +524,9 @@ cpu_arm1020_name:
 __arm1020_proc_info:
 	.long	0x4104a200			@ ARM 1020T (Architecture v5T)
 	.long	0xff0ffff0
+	.long   PMD_TYPE_SECT | \
+		PMD_SECT_AP_WRITE | \
+		PMD_SECT_AP_READ
 	.long   PMD_TYPE_SECT | \
 		PMD_SECT_AP_WRITE | \
 		PMD_SECT_AP_READ

arch/arm/mm/proc-arm1020e.S

@@ -488,6 +488,10 @@ cpu_arm1020e_name:
 __arm1020e_proc_info:
 	.long	0x4105a200			@ ARM 1020TE (Architecture v5TE)
 	.long	0xff0ffff0
+	.long   PMD_TYPE_SECT | \
+		PMD_BIT4 | \
+		PMD_SECT_AP_WRITE | \
+		PMD_SECT_AP_READ
 	.long   PMD_TYPE_SECT | \
 		PMD_BIT4 | \
 		PMD_SECT_AP_WRITE | \

arch/arm/mm/proc-arm1022.S

@@ -471,6 +471,10 @@ cpu_arm1022_name:
 __arm1022_proc_info:
 	.long	0x4105a220			@ ARM 1022E (v5TE)
 	.long	0xff0ffff0
+	.long   PMD_TYPE_SECT | \
+		PMD_BIT4 | \
+		PMD_SECT_AP_WRITE | \
+		PMD_SECT_AP_READ
 	.long   PMD_TYPE_SECT | \
 		PMD_BIT4 | \
 		PMD_SECT_AP_WRITE | \

arch/arm/mm/proc-arm1026.S

@@ -467,6 +467,10 @@ cpu_arm1026_name:
 __arm1026_proc_info:
 	.long	0x4106a260			@ ARM 1026EJ-S (v5TEJ)
 	.long	0xff0ffff0
+	.long   PMD_TYPE_SECT | \
+		PMD_BIT4 | \
+		PMD_SECT_AP_WRITE | \
+		PMD_SECT_AP_READ
 	.long   PMD_TYPE_SECT | \
 		PMD_BIT4 | \
 		PMD_SECT_AP_WRITE | \

arch/arm/mm/proc-arm6_7.S

@@ -355,6 +355,10 @@ __arm6_proc_info:
 		.long	0x41560600
 		.long	0xfffffff0
 		.long	0x00000c1e
+		.long   PMD_TYPE_SECT | \
+			PMD_BIT4 | \
+			PMD_SECT_AP_WRITE | \
+			PMD_SECT_AP_READ
 		b	__arm6_setup
 		.long	cpu_arch_name
 		.long	cpu_elf_name
@@ -371,6 +375,10 @@ __arm610_proc_info:
 		.long	0x41560610
 		.long	0xfffffff0
 		.long	0x00000c1e
+		.long   PMD_TYPE_SECT | \
+			PMD_BIT4 | \
+			PMD_SECT_AP_WRITE | \
+			PMD_SECT_AP_READ
 		b	__arm6_setup
 		.long	cpu_arch_name
 		.long	cpu_elf_name
@@ -387,6 +395,10 @@ __arm7_proc_info:
 		.long	0x41007000
 		.long	0xffffff00
 		.long	0x00000c1e
+		.long   PMD_TYPE_SECT | \
+			PMD_BIT4 | \
+			PMD_SECT_AP_WRITE | \
+			PMD_SECT_AP_READ
 		b	__arm7_setup
 		.long	cpu_arch_name
 		.long	cpu_elf_name
@@ -408,6 +420,10 @@ __arm710_proc_info:
 			PMD_BIT4 | \
 			PMD_SECT_AP_WRITE | \
 			PMD_SECT_AP_READ
+		.long   PMD_TYPE_SECT | \
+			PMD_BIT4 | \
+			PMD_SECT_AP_WRITE | \
+			PMD_SECT_AP_READ
 		b	__arm7_setup
 		.long	cpu_arch_name
 		.long	cpu_elf_name

arch/arm/mm/proc-arm720.S

@@ -246,6 +246,10 @@ __arm710_proc_info:
 			PMD_BIT4 | \
 			PMD_SECT_AP_WRITE | \
 			PMD_SECT_AP_READ
+		.long   PMD_TYPE_SECT | \
+			PMD_BIT4 | \
+			PMD_SECT_AP_WRITE | \
+			PMD_SECT_AP_READ
 		b	__arm710_setup				@ cpu_flush
 		.long	cpu_arch_name				@ arch_name
 		.long	cpu_elf_name				@ elf_name
@@ -267,6 +271,10 @@ __arm720_proc_info:
 			PMD_BIT4 | \
 			PMD_SECT_AP_WRITE | \
 			PMD_SECT_AP_READ
+		.long   PMD_TYPE_SECT | \
+			PMD_BIT4 | \
+			PMD_SECT_AP_WRITE | \
+			PMD_SECT_AP_READ
 		b	__arm720_setup				@ cpu_flush
 		.long	cpu_arch_name				@ arch_name
 		.long	cpu_elf_name				@ elf_name

arch/arm/mm/proc-arm920.S

@@ -461,6 +461,10 @@ __arm920_proc_info:
 		PMD_BIT4 | \
 		PMD_SECT_AP_WRITE | \
 		PMD_SECT_AP_READ
+	.long   PMD_TYPE_SECT | \
+		PMD_BIT4 | \
+		PMD_SECT_AP_WRITE | \
+		PMD_SECT_AP_READ
 	b	__arm920_setup
 	.long	cpu_arch_name
 	.long	cpu_elf_name

arch/arm/mm/proc-arm922.S

@@ -465,6 +465,10 @@ __arm922_proc_info:
 		PMD_BIT4 | \
 		PMD_SECT_AP_WRITE | \
 		PMD_SECT_AP_READ
+	.long   PMD_TYPE_SECT | \
+		PMD_BIT4 | \
+		PMD_SECT_AP_WRITE | \
+		PMD_SECT_AP_READ
 	b	__arm922_setup
 	.long	cpu_arch_name
 	.long	cpu_elf_name

arch/arm/mm/proc-arm925.S

@@ -522,6 +522,10 @@ cpu_arm925_name:
 __arm925_proc_info:
 	.long	0x54029250
 	.long	0xfffffff0
+	.long   PMD_TYPE_SECT | \
+		PMD_BIT4 | \
+		PMD_SECT_AP_WRITE | \
+		PMD_SECT_AP_READ
 	.long   PMD_TYPE_SECT | \
 		PMD_BIT4 | \
 		PMD_SECT_AP_WRITE | \
@@ -541,6 +545,10 @@ __arm925_proc_info:
 __arm915_proc_info:
 	.long	0x54029150
 	.long	0xfffffff0
+	.long   PMD_TYPE_SECT | \
+		PMD_BIT4 | \
+		PMD_SECT_AP_WRITE | \
+		PMD_SECT_AP_READ
 	.long   PMD_TYPE_SECT | \
 		PMD_BIT4 | \
 		PMD_SECT_AP_WRITE | \

arch/arm/mm/proc-arm926.S

@@ -477,6 +477,10 @@ __arm926_proc_info:
 		PMD_BIT4 | \
 		PMD_SECT_AP_WRITE | \
 		PMD_SECT_AP_READ
+	.long   PMD_TYPE_SECT | \
+		PMD_BIT4 | \
+		PMD_SECT_AP_WRITE | \
+		PMD_SECT_AP_READ
 	b	__arm926_setup
 	.long	cpu_arch_name
 	.long	cpu_elf_name

arch/arm/mm/proc-sa110.S

@@ -255,6 +255,9 @@ __sa110_proc_info:
 		PMD_SECT_CACHEABLE | \
 		PMD_SECT_AP_WRITE | \
 		PMD_SECT_AP_READ
+	.long   PMD_TYPE_SECT | \
+		PMD_SECT_AP_WRITE | \
+		PMD_SECT_AP_READ
 	b	__sa110_setup
 	.long	cpu_arch_name
 	.long	cpu_elf_name

arch/arm/mm/proc-sa1100.S

@@ -276,6 +276,9 @@ __sa1100_proc_info:
 		PMD_SECT_CACHEABLE | \
 		PMD_SECT_AP_WRITE | \
 		PMD_SECT_AP_READ
+	.long   PMD_TYPE_SECT | \
+		PMD_SECT_AP_WRITE | \
+		PMD_SECT_AP_READ
 	b	__sa1100_setup
 	.long	cpu_arch_name
 	.long	cpu_elf_name
@@ -296,6 +299,9 @@ __sa1110_proc_info:
 		PMD_SECT_CACHEABLE | \
 		PMD_SECT_AP_WRITE | \
 		PMD_SECT_AP_READ
+	.long   PMD_TYPE_SECT | \
+		PMD_SECT_AP_WRITE | \
+		PMD_SECT_AP_READ
 	b	__sa1100_setup
 	.long	cpu_arch_name
 	.long	cpu_elf_name

arch/arm/mm/proc-v6.S

@@ -269,6 +269,10 @@ __v6_proc_info:
 		PMD_SECT_CACHEABLE | \
 		PMD_SECT_AP_WRITE | \
 		PMD_SECT_AP_READ
+	.long   PMD_TYPE_SECT | \
+		PMD_SECT_XN | \
+		PMD_SECT_AP_WRITE | \
+		PMD_SECT_AP_READ
 	b	__v6_setup
 	.long	cpu_arch_name
 	.long	cpu_elf_name

arch/arm/mm/proc-xsc3.S

@@ -487,7 +487,14 @@ cpu_xsc3_name:
 __xsc3_proc_info:
 	.long	0x69056000
 	.long	0xffffe000
-	.long	0x00000c0e
+	.long	PMD_TYPE_SECT | \
+		PMD_SECT_BUFFERABLE | \
+		PMD_SECT_CACHEABLE | \
+		PMD_SECT_AP_WRITE | \
+		PMD_SECT_AP_READ
+	.long   PMD_TYPE_SECT | \
+		PMD_SECT_AP_WRITE | \
+		PMD_SECT_AP_READ
 	b	__xsc3_setup
 	.long	cpu_arch_name
 	.long	cpu_elf_name

arch/arm/mm/proc-xscale.S

@@ -595,6 +595,9 @@ __80200_proc_info:
 		PMD_SECT_CACHEABLE | \
 		PMD_SECT_AP_WRITE | \
 		PMD_SECT_AP_READ
+	.long   PMD_TYPE_SECT | \
+		PMD_SECT_AP_WRITE | \
+		PMD_SECT_AP_READ
 	b	__xscale_setup
 	.long	cpu_arch_name
 	.long	cpu_elf_name
@@ -615,6 +618,9 @@ __8032x_proc_info:
 		PMD_SECT_CACHEABLE | \
 		PMD_SECT_AP_WRITE | \
 		PMD_SECT_AP_READ
+	.long   PMD_TYPE_SECT | \
+		PMD_SECT_AP_WRITE | \
+		PMD_SECT_AP_READ
 	b	__xscale_setup
 	.long	cpu_arch_name
 	.long	cpu_elf_name
@@ -635,6 +641,9 @@ __8033x_proc_info:
 		PMD_SECT_CACHEABLE | \
 		PMD_SECT_AP_WRITE | \
 		PMD_SECT_AP_READ
+	.long   PMD_TYPE_SECT | \
+		PMD_SECT_AP_WRITE | \
+		PMD_SECT_AP_READ
 	b	__xscale_setup
 	.long	cpu_arch_name
 	.long	cpu_elf_name
@@ -655,6 +664,9 @@ __pxa250_proc_info:
 		PMD_SECT_CACHEABLE | \
 		PMD_SECT_AP_WRITE | \
 		PMD_SECT_AP_READ
+	.long   PMD_TYPE_SECT | \
+		PMD_SECT_AP_WRITE | \
+		PMD_SECT_AP_READ
 	b	__xscale_setup
 	.long	cpu_arch_name
 	.long	cpu_elf_name
@@ -675,6 +687,9 @@ __pxa210_proc_info:
 		PMD_SECT_CACHEABLE | \
 		PMD_SECT_AP_WRITE | \
 		PMD_SECT_AP_READ
+	.long   PMD_TYPE_SECT | \
+		PMD_SECT_AP_WRITE | \
+		PMD_SECT_AP_READ
 	b	__xscale_setup
 	.long	cpu_arch_name
 	.long	cpu_elf_name
@@ -695,6 +710,9 @@ __ixp2400_proc_info:
 		PMD_SECT_CACHEABLE | \
 		PMD_SECT_AP_WRITE | \
 		PMD_SECT_AP_READ
+	.long   PMD_TYPE_SECT | \
+		PMD_SECT_AP_WRITE | \
+		PMD_SECT_AP_READ
 	b       __xscale_setup
 	.long   cpu_arch_name
 	.long   cpu_elf_name
@@ -715,6 +733,9 @@ __ixp2800_proc_info:
 		PMD_SECT_CACHEABLE | \
 		PMD_SECT_AP_WRITE | \
 		PMD_SECT_AP_READ
+	.long   PMD_TYPE_SECT | \
+		PMD_SECT_AP_WRITE | \
+		PMD_SECT_AP_READ
 	b       __xscale_setup
 	.long   cpu_arch_name
 	.long   cpu_elf_name
@@ -735,6 +756,9 @@ __ixp42x_proc_info:
 		PMD_SECT_CACHEABLE | \
 		PMD_SECT_AP_WRITE | \
 		PMD_SECT_AP_READ
+	.long   PMD_TYPE_SECT | \
+		PMD_SECT_AP_WRITE | \
+		PMD_SECT_AP_READ
 	b       __xscale_setup
 	.long   cpu_arch_name
 	.long   cpu_elf_name
@@ -750,7 +774,14 @@ __ixp42x_proc_info:
 __ixp46x_proc_info:
 	.long   0x69054200
 	.long   0xffffff00
-	.long   0x00000c0e
+	.long   PMD_TYPE_SECT | \
+		PMD_SECT_BUFFERABLE | \
+		PMD_SECT_CACHEABLE | \
+		PMD_SECT_AP_WRITE | \
+		PMD_SECT_AP_READ
+	.long   PMD_TYPE_SECT | \
+		PMD_SECT_AP_WRITE | \
+		PMD_SECT_AP_READ
 	b       __xscale_setup
 	.long   cpu_arch_name
 	.long   cpu_elf_name
@@ -771,6 +802,9 @@ __pxa255_proc_info:
 		PMD_SECT_CACHEABLE | \
 		PMD_SECT_AP_WRITE | \
 		PMD_SECT_AP_READ
+	.long   PMD_TYPE_SECT | \
+		PMD_SECT_AP_WRITE | \
+		PMD_SECT_AP_READ
 	b	__xscale_setup
 	.long	cpu_arch_name
 	.long	cpu_elf_name
@@ -791,6 +825,9 @@ __pxa270_proc_info:
 		PMD_SECT_CACHEABLE | \
 		PMD_SECT_AP_WRITE | \
 		PMD_SECT_AP_READ
+	.long   PMD_TYPE_SECT | \
+		PMD_SECT_AP_WRITE | \
+		PMD_SECT_AP_READ
 	b	__xscale_setup
 	.long	cpu_arch_name
 	.long	cpu_elf_name

include/asm-arm/pgtable-hwdef.h

@@ -28,6 +28,7 @@
  */
 #define PMD_SECT_BUFFERABLE	(1 << 2)
 #define PMD_SECT_CACHEABLE	(1 << 3)
+#define PMD_SECT_XN		(1 << 4)	/* v6 */
 #define PMD_SECT_AP_WRITE	(1 << 10)
 #define PMD_SECT_AP_READ	(1 << 11)
 #define PMD_SECT_TEX(x)		((x) << 12)	/* v5 */

include/asm-arm/procinfo.h

@@ -29,7 +29,8 @@ struct processor;
 struct proc_info_list {
 	unsigned int		cpu_val;
 	unsigned int		cpu_mask;
-	unsigned long		__cpu_mmu_flags;	/* used by head.S */
+	unsigned long		__cpu_mm_mmu_flags;	/* used by head.S */
+	unsigned long		__cpu_io_mmu_flags;	/* used by head.S */
 	unsigned long		__cpu_flush;		/* used by head.S */
 	const char		*arch_name;
 	const char		*elf_name;