From 816242da3735957bee99aeba40aa60c4f120a101 Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Mon, 23 May 2005 15:52:08 -0700 Subject: [SPARC64]: Add boot option to force UltraSPARC-III P-Cache on. Older UltraSPARC-III chips have a P-Cache bug that makes us disable it by default at boot time. However, this does hurt performance substantially, particularly with memcpy(), and the bug is _incredibly_ obscure. I have never seen it triggered in practice, ever. So provide a "-P" boot option that forces the P-Cache on. It taints the kernel, so if it does trigger and cause some data corruption or OOPS, we will find out in the logs that this option was on when it happened. Signed-off-by: David S. Miller --- arch/sparc64/kernel/setup.c | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'arch/sparc64/kernel/setup.c') diff --git a/arch/sparc64/kernel/setup.c b/arch/sparc64/kernel/setup.c index 12c3d84b746..b7e6a91952b 100644 --- a/arch/sparc64/kernel/setup.c +++ b/arch/sparc64/kernel/setup.c @@ -383,6 +383,17 @@ static void __init process_switch(char c) /* Use PROM debug console. */ register_console(&prom_debug_console); break; + case 'P': + /* Force UltraSPARC-III P-Cache on. */ + if (tlb_type != cheetah) { + printk("BOOT: Ignoring P-Cache force option.\n"); + break; + } + cheetah_pcache_forced_on = 1; + add_taint(TAINT_MACHINE_CHECK); + cheetah_enable_pcache(); + break; + default: printk("Unknown boot switch (-%c)\n", c); break; -- cgit v1.2.3