ARM: make the physical-relative calculation more obvious

The physical-relative calculation between the XIP text and data sections
introduced by the previous patch was far from obvious. Let's simplify it
by turning it into a macro which takes the two (virtual) addresses.

This allows us to arrange the calculation in a more obvious manner - we
can make it two sub-expressions which calculate the physical address for
each symbol, and then takes the difference of those physical addresses.

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

diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h
index ebdaaf7dd19f4b3bdd39169524ed70ee4caa1c34..51fc9b3b52eac073e53c022a85d29d0b292c774a 100644 (file)
--- a/arch/arm/include/asm/memory.h
+++ b/arch/arm/include/asm/memory.h
@@ -135,11 +135,18 @@
 #define PLAT_PHYS_OFFSET       UL(CONFIG_PHYS_OFFSET)
 
 #ifdef CONFIG_XIP_KERNEL
-#define PHYS_OFFSET_FIXUP \
-       ( XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR) - PAGE_OFFSET + \
-         PLAT_PHYS_OFFSET - CONFIG_XIP_PHYS_ADDR )
+/*
+ * When referencing data in RAM from the XIP region in a relative manner
+ * with the MMU off, we need the relative offset between the two physical
+ * addresses.  The macro below achieves this, which is:
+ *    __pa(v_data) - __xip_pa(v_text)
+ */
+#define PHYS_RELATIVE(v_data, v_text) \
+       (((v_data) - PAGE_OFFSET + PLAT_PHYS_OFFSET) - \
+        ((v_text) - XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR) + \
+          CONFIG_XIP_PHYS_ADDR))
 #else
-#define PHYS_OFFSET_FIXUP 0
+#define PHYS_RELATIVE(v_data, v_text) ((v_data) - (v_text))
 #endif
 
 #ifndef __ASSEMBLY__

diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
index 1595fb29ec12d2a664c3a0df7afa06d5b2514496..0f8963a7e7d9db28465c63a2bab69a615fb6a2cb 100644 (file)
--- a/arch/arm/mm/proc-v7.S
+++ b/arch/arm/mm/proc-v7.S
@@ -487,7 +487,7 @@ __errata_finish:
 
        .align  2
 __v7_setup_stack_ptr:
-       .word   __v7_setup_stack - . + PHYS_OFFSET_FIXUP
+       .word   PHYS_RELATIVE(__v7_setup_stack, .)
 ENDPROC(__v7_setup)
 
        .bss