Just love to find this during my exploration of linux Kernel Worshipper ARM assembly code made yourself pleasure !
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/*
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/linkage.h>
#include <linux/init.h>
__CPUINIT
ENTRY(special_secondary_startup)
mrc p15, 0, r0, c0, c0, 5 @Read MPIDR
and r0, r0, #15 @Mask CPUID
adr r4, 1f
ldmia r4, {r5, r6}
sub r4, r4, r5
add r6, r6, r4
pen: ldr r7, [r6]
cmp r7, r0
bne pen
* we've been released from the holding pen: secondary_stack
* should now contain the SVC stack for this core
b secondary_startup
.align
1: .long .
.long pen_release
==================================
Who can tell me where it comes from and what it is used for?