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Commit 7d2f6075 authored by Nathan Lynch's avatar Nathan Lynch Committed by Benjamin Herrenschmidt
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powerpc: kill useless SMT code in prom_hold_cpus 



This piece of code is broken for >2 threads, and possibly in some
other subtle ways (such as comparing a value obtained from an
"ibm,ppc-interrupt-server#s" property to a value obtained from a
"reg" property) and doesn't seem to have any useful purpose in the
first place other than a dubious warning in case NR_CPUS is too
small, which probably isn't the right place to do so.

Signed-off-by: default avatarNathan Lynch <ntl@pobox.com>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent ff8dc769

arch/powerpc/kernel/prom_init.c

+3 −36
Original line number Diff line number Diff line
@@ -205,8 +205,6 @@ static int __initdata mem_reserve_cnt; 
static cell_t __initdata regbuf[1024];





#define MAX_CPU_THREADS 2



/*

 * Error results ... some OF calls will return "-1" on error, some

 * will return 0, some will return either. To simplify, here are
@@ -1339,10 +1337,6 @@ static void __init prom_hold_cpus(void) 
	unsigned int reg;

	phandle node;

	char type[64];

	int cpuid = 0;

	unsigned int interrupt_server[MAX_CPU_THREADS];

	unsigned int cpu_threads, hw_cpu_num;

	int propsize;

	struct prom_t *_prom = &RELOC(prom);

	unsigned long *spinloop

		= (void *) LOW_ADDR(__secondary_hold_spinloop);
@@ -1386,7 +1380,6 @@ static void __init prom_hold_cpus(void) 
		reg = -1;

		prom_getprop(node, "reg", &reg, sizeof(reg));



		prom_debug("\ncpuid        = 0x%x\n", cpuid);

		prom_debug("cpu hw idx   = 0x%x\n", reg);



		/* Init the acknowledge var which will be reset by
@@ -1395,28 +1388,9 @@ static void __init prom_hold_cpus(void) 
		 */

		*acknowledge = (unsigned long)-1;



		propsize = prom_getprop(node, "ibm,ppc-interrupt-server#s",

					&interrupt_server,

					sizeof(interrupt_server));

		if (propsize < 0) {

			/* no property.  old hardware has no SMT */

			cpu_threads = 1;

			interrupt_server[0] = reg; /* fake it with phys id */

		} else {

			/* We have a threaded processor */

			cpu_threads = propsize / sizeof(u32);

			if (cpu_threads > MAX_CPU_THREADS) {

				prom_printf("SMT: too many threads!\n"

					    "SMT: found %x, max is %x\n",

					    cpu_threads, MAX_CPU_THREADS);

				cpu_threads = 1; /* ToDo: panic? */

			}

		}



		hw_cpu_num = interrupt_server[0];

		if (hw_cpu_num != _prom->cpu) {

		if (reg != _prom->cpu) {

			/* Primary Thread of non-boot cpu */

			prom_printf("%x : starting cpu hw idx %x... ", cpuid, reg);

			prom_printf("starting cpu hw idx %x... ", reg);

			call_prom("start-cpu", 3, 0, node,

				  secondary_hold, reg);
@@ -1431,17 +1405,10 @@ static void __init prom_hold_cpus(void) 
		}

#ifdef CONFIG_SMP

		else

			prom_printf("%x : boot cpu     %x\n", cpuid, reg);

			prom_printf("boot cpu hw idx %x\n", reg);

#endif /* CONFIG_SMP */



		/* Reserve cpu #s for secondary threads.   They start later. */

		cpuid += cpu_threads;

	}



	if (cpuid > NR_CPUS)

		prom_printf("WARNING: maximum CPUs (" __stringify(NR_CPUS)

			    ") exceeded: ignoring extras\n");



	prom_debug("prom_hold_cpus: end...\n");

}