[PATCH 1/6] ARM: fix be8 support for phys/virt address conversion
Junxiao Bi
junxiao.bi at windriver.com
Thu Dec 8 05:07:47 EST 2011
phys_to_virt() and virt_to_phys() is implemented by one assembler instruction,
add/sub an offset between the physical and virtual address. For some arm machines
with CONFIG_ARM_PATCH_PHYS_VIRT defined, this offset is unknown at compile time,
it is calculated dynamically at run time and then patched to the add/sub instruction.
To support BE8 mode, firstly we need to convert the instruntion to big-endian after
loading it from the memory, and then modify its offset field, at last convert it to
little-endian and write it back to the memory.
Reviewed-by: Nicolas Pitre <nico at linaro.org>
Signed-off-by: Junxiao Bi <junxiao.bi at windriver.com>
---
arch/arm/kernel/head.S | 12 ++++++++++++
1 files changed, 12 insertions(+), 0 deletions(-)
diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index 54fa641..a52aec7 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -565,8 +565,14 @@ __fixup_a_pv_table:
b 2f
1: add r7, r3
ldrh ip, [r7, #2]
+#ifdef CONFIG_CPU_ENDIAN_BE8
+ rev16 ip, ip
+#endif
and ip, 0x8f00
orr ip, r6 @ mask in offset bits 31-24
+#ifdef CONFIG_CPU_ENDIAN_BE8
+ rev16 ip, ip
+#endif
strh ip, [r7, #2]
2: cmp r4, r5
ldrcc r7, [r4], #4 @ use branch for delay slot
@@ -575,8 +581,14 @@ __fixup_a_pv_table:
#else
b 2f
1: ldr ip, [r7, r3]
+#ifdef CONFIG_CPU_ENDIAN_BE8
+ rev ip, ip
+#endif
bic ip, ip, #0x000000ff
orr ip, ip, r6 @ mask in offset bits 31-24
+#ifdef CONFIG_CPU_ENDIAN_BE8
+ rev ip, ip
+#endif
str ip, [r7, r3]
2: cmp r4, r5
ldrcc r7, [r4], #4 @ use branch for delay slot
--
1.7.0.4
More information about the linux-mtd
mailing list