From mboxrd@z Thu Jan 1 00:00:00 1970 From: santosh.shilimkar@ti.com (Santosh Shilimkar) Date: Sat, 12 Jan 2013 00:00:08 +0530 Subject: [PATCH 01/16] ARM: b.L: secondary kernel entry code In-Reply-To: References: <1357777251-13541-1-git-send-email-nicolas.pitre@linaro.org> <1357777251-13541-2-git-send-email-nicolas.pitre@linaro.org> <50F048D7.6000904@ti.com> Message-ID: <50F05A30.7030704@ti.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Friday 11 January 2013 11:40 PM, Nicolas Pitre wrote: > On Fri, 11 Jan 2013, Santosh Shilimkar wrote: > >> On Thursday 10 January 2013 05:50 AM, Nicolas Pitre wrote: >>> +ENTRY(bL_entry_point) >>> + >>> + THUMB( adr r12, BSYM(1f) ) >>> + THUMB( bx r12 ) >>> + THUMB( .thumb ) >>> +1: >>> + mrc p15, 0, r0, c0, c0, 5 >>> + ubfx r9, r0, #0, #4 @ r9 = cpu >>> + ubfx r10, r0, #8, #4 @ r10 = cluster >>> + mov r3, #BL_CPUS_PER_CLUSTER >>> + mla r4, r3, r10, r9 @ r4 = canonical CPU index >>> + cmp r4, #(BL_CPUS_PER_CLUSTER * BL_NR_CLUSTERS) >>> + blo 2f >>> + >>> + /* We didn't expect this CPU. Try to make it quiet. */ >>> +1: wfi >>> + wfe >> >> Why do you need a wfe followed by wif ? >> Just curious. > > If the WFI doesn't work because an interrupt is pending then the WFE > might work better. But as I mentioned before, this is not intended to > be used for other purposes than "we're really screwed so at least let's > try to cheaply quieten this CPU" case. > Thanks for clarification. Regards Santosh