ARM: Allow SMP kernels to boot on UP systems
UP systems do not implement all the instructions that SMP systems have,
so in order to boot a SMP kernel on a UP system, we need to rewrite
parts of the kernel.
Do this using an 'alternatives' scheme, where the kernel code and data
is modified prior to initialization to replace the SMP instructions,
thereby rendering the problematical code ineffectual. We use the linker
to generate a list of 32-bit word locations and their replacement values,
and run through these replacements when we detect a UP system.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mm/cache-v7.S b/arch/arm/mm/cache-v7.S
index 37c8157..e8ea1a0 100644
--- a/arch/arm/mm/cache-v7.S
+++ b/arch/arm/mm/cache-v7.S
@@ -91,11 +91,8 @@
THUMB( stmfd sp!, {r4-r7, r9-r11, lr} )
bl v7_flush_dcache_all
mov r0, #0
-#ifdef CONFIG_SMP
- mcr p15, 0, r0, c7, c1, 0 @ invalidate I-cache inner shareable
-#else
- mcr p15, 0, r0, c7, c5, 0 @ I+BTB cache invalidate
-#endif
+ ALT_SMP(mcr p15, 0, r0, c7, c1, 0) @ invalidate I-cache inner shareable
+ ALT_UP(mcr p15, 0, r0, c7, c5, 0) @ I+BTB cache invalidate
ARM( ldmfd sp!, {r4-r5, r7, r9-r11, lr} )
THUMB( ldmfd sp!, {r4-r7, r9-r11, lr} )
mov pc, lr
@@ -171,11 +168,8 @@
cmp r0, r1
blo 1b
mov r0, #0
-#ifdef CONFIG_SMP
- mcr p15, 0, r0, c7, c1, 6 @ invalidate BTB Inner Shareable
-#else
- mcr p15, 0, r0, c7, c5, 6 @ invalidate BTB
-#endif
+ ALT_SMP(mcr p15, 0, r0, c7, c1, 6) @ invalidate BTB Inner Shareable
+ ALT_UP(mcr p15, 0, r0, c7, c5, 6) @ invalidate BTB
dsb
isb
mov pc, lr