| Message ID | 1496781149-648310-1-git-send-email-jane.chu@oracle.com |
|---|---|
| State | Accepted |
| Delegated to: | David Miller |
| Headers | show |
From: Jane Chu <jane.chu@oracle.com> Date: Tue, 6 Jun 2017 14:32:29 -0600 > 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@oracle.com> > > Reviewed-by: Bob Picco <bob.picco@oracle.com> > Reviewed-by: Atish Patra <atish.patra@oracle.com> Looks a lot better, applied, thanks! -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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..99dd133 100644 --- a/arch/sparc/kernel/irq_64.c +++ b/arch/sparc/kernel/irq_64.c @@ -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 }