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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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f533c3d340
This does a bit of chainsawing of the idle loop code to get light sleep working on SMP. Previously this was forcing secondary CPUs in to sleep mode with them not coming back if they didn't have their own local timers. Given that we use clockevents broadcasting by default, the CPU managing the clockevents can't have IRQs disabled before entering its sleep state. This unfortunately leaves us with the age-old need_resched() race in between local_irq_enable() and cpu_sleep(), but at present this is unavoidable. After some more experimentation it may be possible to layer on SR.BL bit manipulation over top of this scheme to inhibit the race condition, but given the current potential for missing wakeups, this is left as a future exercise. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
78 lines
1.3 KiB
C
78 lines
1.3 KiB
C
#ifndef __ASM_SH_BUGS_H
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#define __ASM_SH_BUGS_H
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/*
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* This is included by init/main.c to check for architecture-dependent bugs.
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*
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* Needs:
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* void check_bugs(void);
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*/
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/*
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* I don't know of any Super-H bugs yet.
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*/
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#include <asm/processor.h>
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extern void select_idle_routine(void);
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static void __init check_bugs(void)
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{
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extern unsigned long loops_per_jiffy;
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char *p = &init_utsname()->machine[2]; /* "sh" */
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select_idle_routine();
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current_cpu_data.loops_per_jiffy = loops_per_jiffy;
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switch (current_cpu_data.family) {
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case CPU_FAMILY_SH2:
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*p++ = '2';
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break;
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case CPU_FAMILY_SH2A:
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*p++ = '2';
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*p++ = 'a';
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break;
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case CPU_FAMILY_SH3:
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*p++ = '3';
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break;
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case CPU_FAMILY_SH4:
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*p++ = '4';
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break;
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case CPU_FAMILY_SH4A:
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*p++ = '4';
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*p++ = 'a';
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break;
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case CPU_FAMILY_SH4AL_DSP:
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*p++ = '4';
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*p++ = 'a';
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*p++ = 'l';
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*p++ = '-';
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*p++ = 'd';
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*p++ = 's';
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*p++ = 'p';
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break;
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case CPU_FAMILY_SH5:
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*p++ = '6';
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*p++ = '4';
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break;
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case CPU_FAMILY_UNKNOWN:
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/*
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* Specifically use CPU_FAMILY_UNKNOWN rather than
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* default:, so we're able to have the compiler whine
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* about unhandled enumerations.
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*/
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break;
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}
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printk("CPU: %s\n", get_cpu_subtype(¤t_cpu_data));
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#ifndef __LITTLE_ENDIAN__
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/* 'eb' means 'Endian Big' */
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*p++ = 'e';
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*p++ = 'b';
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#endif
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*p = '\0';
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}
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#endif /* __ASM_SH_BUGS_H */
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