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-rw-r--r--arch/arm/kernel/head.S50
1 files changed, 50 insertions, 0 deletions
diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index eb62bf947212..b44d21e1e344 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -86,6 +86,9 @@ ENTRY(stext)
movs r8, r5 @ invalid machine (r5=0)?
beq __error_a @ yes, error 'a'
bl __vet_atags
+#ifdef CONFIG_SMP_ON_UP
+ bl __fixup_smp
+#endif
bl __create_page_tables
/*
@@ -333,4 +336,51 @@ __create_page_tables:
ENDPROC(__create_page_tables)
.ltorg
+#ifdef CONFIG_SMP_ON_UP
+__fixup_smp:
+ mov r7, #0x00070000
+ orr r6, r7, #0xff000000 @ mask 0xff070000
+ orr r7, r7, #0x41000000 @ val 0x41070000
+ and r0, r9, r6
+ teq r0, r7 @ ARM CPU and ARMv6/v7?
+ bne __fixup_smp_on_up @ no, assume UP
+
+ orr r6, r6, #0x0000ff00
+ orr r6, r6, #0x000000f0 @ mask 0xff07fff0
+ orr r7, r7, #0x0000b000
+ orr r7, r7, #0x00000020 @ val 0x4107b020
+ and r0, r9, r6
+ teq r0, r7 @ ARM 11MPCore?
+ moveq pc, lr @ yes, assume SMP
+
+ mrc p15, 0, r0, c0, c0, 5 @ read MPIDR
+ tst r0, #1 << 31
+ movne pc, lr @ bit 31 => SMP
+
+__fixup_smp_on_up:
+ adr r0, 1f
+ ldmia r0, {r3, r6, r7}
+ sub r3, r0, r3
+ add r6, r6, r3
+ add r7, r7, r3
+2: cmp r6, r7
+ ldmia r6!, {r0, r4}
+ strlo r4, [r0, r3]
+ blo 2b
+ mov pc, lr
+ENDPROC(__fixup_smp)
+
+1: .word .
+ .word __smpalt_begin
+ .word __smpalt_end
+
+ .pushsection .data
+ .globl smp_on_up
+smp_on_up:
+ ALT_SMP(.long 1)
+ ALT_UP(.long 0)
+ .popsection
+
+#endif
+
#include "head-common.S"
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