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: Jane Chu <jane.chu@xxxxxxxxxx>
Reviewed-by: Bob Picco <bob.picco@xxxxxxxxxx>
Reviewed-by: Atish Patra <atish.patra@xxxxxxxxxx>
---
arch/sparc/Kconfig | 4 ++--
arch/sparc/kernel/irq_64.c | 8 ++++----
2 files changed, 6 insertions(+), 6 deletions(-)
diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index 58243b0..4399be7 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -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
diff --git a/arch/sparc/kernel/irq_64.c b/arch/sparc/kernel/irq_64.c
index 4d0248a..5b19108 100644
--- a/arch/sparc/kernel/irq_64.c
+++ b/arch/sparc/kernel/irq_64.c
@@ -1034,12 +1034,12 @@ static void __init init_cpu_send_mondo_info(struct trap_per_cpu *tb)
{
#ifdef CONFIG_SMP
unsigned long page;
+ unsigned int order;
- BUILD_BUG_ON((NR_CPUS * sizeof(u16)) > (PAGE_SIZE - 64));
-
- page = get_zeroed_page(GFP_KERNEL);
+ order = get_order(num_possible_cpus() * sizeof(u16) + 64);
+ page = __get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
if (!page) {
- prom_printf("SUN4V: Error, cannot allocate cpu mondo page.\n");
+ prom_printf("SUN4V: Error, cannot allocate cpu mondo pages.\n");
prom_halt();
}
--
1.7.1
--
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