diff options
| author | Heiko Carstens <hca@linux.ibm.com> | 2025-03-10 10:33:40 +0100 |
|---|---|---|
| committer | Vasily Gorbik <gor@linux.ibm.com> | 2025-03-18 17:13:04 +0100 |
| commit | 4797e9b5067e3682020b3f6745a929d690370be3 (patch) | |
| tree | 25332b8d11925a1311f88a15ec2375cac448fe3e | |
| parent | 65c07e91cc31700ca8484d3bcd96e49b0053b57b (diff) | |
s390/smp: Implement raw_smp_processor_id() with inline assembly
Implement raw_smp_processor_id() with an inline assembly, which makes
use of the ALTERNATIVE macro, to read cpu_nr from lowcore. Provide an
alternative instruction with a different offset in case lowcore is
relocated.
This replaces sequences of two instructions with one instruction.
Before:
1000b6: a5 1e 00 00 llilh %r1,0
1000ba: 58 20 13 a0 l %r2,928(%r1)
After:
1000b6: e3 20 03 a0 00 58 ly %r2,928
Kernel image size change:
add/remove: 753/755 grow/shrink: 230/1510 up/down: 30538/-35832 (-5294)
Acked-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
| -rw-r--r-- | arch/s390/include/asm/smp.h | 24 |
1 files changed, 21 insertions, 3 deletions
diff --git a/arch/s390/include/asm/smp.h b/arch/s390/include/asm/smp.h index 7feca96c48c6..03f4d01664f8 100644 --- a/arch/s390/include/asm/smp.h +++ b/arch/s390/include/asm/smp.h @@ -7,11 +7,29 @@ #ifndef __ASM_SMP_H #define __ASM_SMP_H -#include <asm/sigp.h> -#include <asm/lowcore.h> #include <asm/processor.h> +#include <asm/lowcore.h> +#include <asm/machine.h> +#include <asm/sigp.h> + +static __always_inline unsigned int raw_smp_processor_id(void) +{ + unsigned long lc_cpu_nr; + unsigned int cpu; + + BUILD_BUG_ON(sizeof_field(struct lowcore, cpu_nr) != sizeof(cpu)); + lc_cpu_nr = offsetof(struct lowcore, cpu_nr); + asm_inline( + ALTERNATIVE(" ly %[cpu],%[offzero](%%r0)\n", + " ly %[cpu],%[offalt](%%r0)\n", + ALT_FEATURE(MFEATURE_LOWCORE)) + : [cpu] "=d" (cpu) + : [offzero] "i" (lc_cpu_nr), + [offalt] "i" (lc_cpu_nr + LOWCORE_ALT_ADDRESS), + "m" (((struct lowcore *)0)->cpu_nr)); + return cpu; +} -#define raw_smp_processor_id() (get_lowcore()->cpu_nr) #define arch_scale_cpu_capacity smp_cpu_get_capacity extern struct mutex smp_cpu_state_mutex; |