From 7f3bbb82e0c371d6881129f776c90130ba66f051 Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Fri, 12 Jul 2013 09:36:21 -0700 Subject: alpha: Primitive support for CPU power down. Use WTINT to wait for the next interrupt. Squash the WTINT call if the PALcode doesn't support it (e.g. MILO). No attempt is yet made to skip clock ticks during normal scheduling in order to stay in power down mode longer. Signed-off-by: Richard Henderson --- arch/alpha/kernel/traps.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'arch/alpha/kernel/traps.c') diff --git a/arch/alpha/kernel/traps.c b/arch/alpha/kernel/traps.c index bd0665cdc840..9c4c189eb22f 100644 --- a/arch/alpha/kernel/traps.c +++ b/arch/alpha/kernel/traps.c @@ -241,6 +241,21 @@ do_entIF(unsigned long type, struct pt_regs *regs) (const char *)(data[1] | (long)data[2] << 32), data[0]); } +#ifdef CONFIG_ALPHA_WTINT + if (type == 4) { + /* If CALL_PAL WTINT is totally unsupported by the + PALcode, e.g. MILO, "emulate" it by overwriting + the insn. */ + unsigned int *pinsn + = (unsigned int *) regs->pc - 1; + if (*pinsn == PAL_wtint) { + *pinsn = 0x47e01400; /* mov 0,$0 */ + imb(); + regs->r0 = 0; + return; + } + } +#endif /* ALPHA_WTINT */ die_if_kernel((type == 1 ? "Kernel Bug" : "Instruction fault"), regs, type, NULL); } -- cgit