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| author | Russell King <rmk+kernel@arm.linux.org.uk> | 2010-09-04 13:47:48 +0400 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2010-10-04 23:23:36 +0400 |
| commit | f00ec48fadf5e37e7889f14cff900aa70d18b644 (patch) | |
| tree | 421cbce97167a78532aa825624f380caade3c0d2 /arch/arm/include/asm/smp_plat.h | |
| parent | 067173526c3bbc2eaeefcf6b7b2a9d998b9e8042 (diff) | |
| download | linux-f00ec48fadf5e37e7889f14cff900aa70d18b644.tar.xz | |
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_plat.h')
| -rw-r--r-- | arch/arm/include/asm/smp_plat.h | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/arch/arm/include/asm/smp_plat.h b/arch/arm/include/asm/smp_plat.h index e6215305544a..7de5aa56c18b 100644 --- a/arch/arm/include/asm/smp_plat.h +++ b/arch/arm/include/asm/smp_plat.h @@ -18,4 +18,19 @@ static inline int cache_ops_need_broadcast(void) return ((read_cpuid_ext(CPUID_EXT_MMFR3) >> 12) & 0xf) < 1; } +/* + * Return true if we are running on a SMP platform + */ +static inline bool is_smp(void) +{ +#ifndef CONFIG_SMP + return false; +#elif defined(CONFIG_SMP_ON_UP) + extern unsigned int smp_on_up; + return !!smp_on_up; +#else + return true; +#endif +} + #endif |