Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit c79a1373 authored by Jane Chu's avatar Jane Chu Committed by David S. Miller
Browse files

arch/sparc: support NR_CPUS = 4096 



Linux SPARC64 limits NR_CPUS to 4064 because init_cpu_send_mondo_info()
only allocates a single page for NR_CPUS mondo entries. Thus we cannot
use all 4096 CPUs on some SPARC platforms.

To fix, allocate (2^order) pages where order is set according to the size
of cpu_list for possible cpus. Since cpu_list_pa and cpu_mondo_block_pa
are not used in asm code, there are no imm13 offsets from the base PA
that will break because they can only reach one page.

Orabug: 25505750

Signed-off-by: default avatarJane Chu <jane.chu@oracle.com>

Reviewed-by: default avatarBob Picco <bob.picco@oracle.com>
Reviewed-by: default avatarAtish Patra <atish.patra@oracle.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 1b4af13f

arch/sparc/Kconfig

+2 −2
Original line number Diff line number Diff line
@@ -192,9 +192,9 @@ config NR_CPUS 
	int "Maximum number of CPUs"

	depends on SMP

	range 2 32 if SPARC32

	range 2 1024 if SPARC64

	range 2 4096 if SPARC64

	default 32 if SPARC32

	default 64 if SPARC64

	default 4096 if SPARC64



source kernel/Kconfig.hz

arch/sparc/kernel/irq_64.c

+13 −4
Original line number Diff line number Diff line
@@ -1034,17 +1034,26 @@ static void __init init_cpu_send_mondo_info(struct trap_per_cpu *tb) 
{

#ifdef CONFIG_SMP

	unsigned long page;

	void *mondo, *p;



	BUILD_BUG_ON((NR_CPUS * sizeof(u16)) > (PAGE_SIZE - 64));

	BUILD_BUG_ON((NR_CPUS * sizeof(u16)) > PAGE_SIZE);



	/* Make sure mondo block is 64byte aligned */

	p = kzalloc(127, GFP_KERNEL);

	if (!p) {

		prom_printf("SUN4V: Error, cannot allocate mondo block.\n");

		prom_halt();

	}

	mondo = (void *)(((unsigned long)p + 63) & ~0x3f);

	tb->cpu_mondo_block_pa = __pa(mondo);



	page = get_zeroed_page(GFP_KERNEL);

	if (!page) {

		prom_printf("SUN4V: Error, cannot allocate cpu mondo page.\n");

		prom_printf("SUN4V: Error, cannot allocate cpu list page.\n");

		prom_halt();

	}



	tb->cpu_mondo_block_pa = __pa(page);

	tb->cpu_list_pa = __pa(page + 64);

	tb->cpu_list_pa = __pa(page);

#endif

}