kernel_optimize_test/arch/arm/include/asm/smp_mpidr.h
Russell King f00ec48fad 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>
2010-10-04 20:23:36 +01:00

18 lines
373 B
C

#ifndef ASMARM_SMP_MIDR_H
#define ASMARM_SMP_MIDR_H
#define hard_smp_processor_id() \
({ \
unsigned int cpunum; \
__asm__("\n" \
"1: mrc p15, 0, %0, c0, c0, 5\n" \
" .pushsection \".alt.smp.init\", \"a\"\n"\
" .long 1b\n" \
" mov %0, #0\n" \
" .popsection" \
: "=r" (cpunum)); \
cpunum &= 0x0F; \
})
#endif