ARM: 7657/1: head: fix swapper and idmap population with LPAE and big-endian

The LPAE page table format uses 64-bit descriptors, so we need to take
endianness into account when populating the swapper and idmap tables
during early initialisation.

This patch ensures that we store the two words making up each page table
entry in the correct order when running big-endian.

Cc: <stable@vger.kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 22 insertions, 4 deletions

diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index 486a15ae9011..e0eb9a1cae77 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -184,13 +184,22 @@ __create_page_tables:
         orr     r3, r3, #3                      @ PGD block type
         mov     r6, #4                          @ PTRS_PER_PGD
         mov     r7, #1 << (55 - 32)             @ L_PGD_SWAPPER
-1:      str     r3, [r0], #4                    @ set bottom PGD entry bits
+1:
+#ifdef CONFIG_CPU_ENDIAN_BE8
         str     r7, [r0], #4                    @ set top PGD entry bits
+        str     r3, [r0], #4                    @ set bottom PGD entry bits
+#else
+        str     r3, [r0], #4                    @ set bottom PGD entry bits
+        str     r7, [r0], #4                    @ set top PGD entry bits
+#endif
         add     r3, r3, #0x1000                 @ next PMD table
         subs    r6, r6, #1
         bne     1b
 
         add     r4, r4, #0x1000                 @ point to the PMD tables
+#ifdef CONFIG_CPU_ENDIAN_BE8
+        add     r4, r4, #4                      @ we only write the bottom word
+#endif
 #endif
 
         ldr     r7, [r10, #PROCINFO_MM_MMUFLAGS] @ mm_mmuflags
@@ -258,6 +267,11 @@ __create_page_tables:
         addne   r6, r6, #1 << SECTION_SHIFT
         strne   r6, [r3]
 
+#if defined(CONFIG_LPAE) && defined(CONFIG_CPU_ENDIAN_BE8)
+        sub     r4, r4, #4                      @ Fixup page table pointer
+                                                @ for 64-bit descriptors
+#endif
+
 #ifdef CONFIG_DEBUG_LL
 #if !defined(CONFIG_DEBUG_ICEDCC) && !defined(CONFIG_DEBUG_SEMIHOSTING)
         /*
@@ -276,13 +290,17 @@ __create_page_tables:
         orr     r3, r7, r3, lsl #SECTION_SHIFT
 #ifdef CONFIG_ARM_LPAE
         mov     r7, #1 << (54 - 32)             @ XN
+#ifdef CONFIG_CPU_ENDIAN_BE8
+        str     r7, [r0], #4
+        str     r3, [r0], #4
 #else
-        orr     r3, r3, #PMD_SECT_XN
-#endif
         str     r3, [r0], #4
-#ifdef CONFIG_ARM_LPAE
         str     r7, [r0], #4
 #endif
+#else
+        orr     r3, r3, #PMD_SECT_XN
+        str     r3, [r0], #4
+#endif
 
 #else /* CONFIG_DEBUG_ICEDCC || CONFIG_DEBUG_SEMIHOSTING */
         /* we don't need any serial debugging mappings */