From: Michael Ellerman Date: Thu, 25 Apr 2013 19:28:23 +0000 (+0000) Subject: powerpc/perf: Add an explict flag indicating presence of SLOT field X-Git-Tag: omap-for-v3.10/dt-fixes-for-merge-window~66^2~40 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7a7868326d77416018e8f3b4c4697a3c57444549;p=pandora-kernel.git powerpc/perf: Add an explict flag indicating presence of SLOT field In perf_ip_adjust() we potentially use the MMCRA[SLOT] field to adjust the reported IP of a sampled instruction. Currently the logic is written so that if the backend does NOT have the PPMU_ALT_SIPR flag set then we assume MMCRA[SLOT] exists. However on power8 we do not want to set ALT_SIPR (it's in a third location), and we also do not have MMCRA[SLOT]. So add a new flag which only indicates whether MMCRA[SLOT] exists. Naively we'd set it on everything except power6/7, because they set ALT_SIPR, and we've reversed the polarity of the flag. But it's more complicated than that. mpc7450 is 32-bit, and uses its own version of perf_ip_adjust() which doesn't use MMCRA[SLOT], so it doesn't need the new flag set and the behaviour is unchanged. PPC970 (and I assume power4) don't have MMCRA[SLOT], so shouldn't have the new flag set. This is a behaviour change on those cpus, though we were probably getting lucky and the bits in question were 0. power5 and power5+ set the new flag, behaviour unchanged. power6 & power7 do not set the new flag, behaviour unchanged. Signed-off-by: Michael Ellerman Acked-by: Paul Mackerras Signed-off-by: Benjamin Herrenschmidt --- Reading git-diff-tree failed