diff options
| author | Russell King <rmk+kernel@arm.linux.org.uk> | 2010-09-04 10:47:48 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2010-10-04 20:23:36 +0100 |
| commit | f00ec48fadf5e37e7889f14cff900aa70d18b644 (patch) | |
| tree | 421cbce97167a78532aa825624f380caade3c0d2 /arch/arm/include/asm/smp_mpidr.h | |
| parent | 067173526c3bbc2eaeefcf6b7b2a9d998b9e8042 (diff) | |
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>
Diffstat (limited to 'arch/arm/include/asm/smp_mpidr.h')
| -rw-r--r-- | arch/arm/include/asm/smp_mpidr.h | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/arch/arm/include/asm/smp_mpidr.h b/arch/arm/include/asm/smp_mpidr.h index 7da7105e83e5..6a9307d64900 100644 --- a/arch/arm/include/asm/smp_mpidr.h +++ b/arch/arm/include/asm/smp_mpidr.h @@ -4,7 +4,12 @@ #define hard_smp_processor_id() \ ({ \ unsigned int cpunum; \ - __asm__("mrc p15, 0, %0, c0, c0, 5\n" \ + __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; \ }) |