Re: [PATCH v2 2/3] ppc64: Avoid rfid if no need to clear MSR_LE
From: Simon Horman <horms@verge.net.au>
Date: 2015-10-16 01:54:51
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kexec
On Tue, Oct 06, 2015 at 05:55:49PM -0500, Scott Wood wrote:
Commit a304e2d82a8c3 ("ppc64: purgatory: Reset primary cpu endian to
big-endian) changed bctr to rfid. rfid is book3s-only and will cause a
fatal exception on book3e.
Purgatory is an isolated environment which makes importing information
about the subarch awkward, so instead rely on the fact that MSR_LE
should never be set on book3e, and the rfid is only needed if MSR_LE is
set (and thus needs to be cleared). In theory that MSR bit is reserved
on book3e, rather than zero, but in practice I have not seen it set.
Signed-off-by: Scott Wood <redacted>
Cc: Samuel Mendoza-Jonas <redacted>
---
v2: new patchCould I get a review of this from at lest one ppc person?
quoted hunk ↗ jump to hunk
purgatory/arch/ppc64/v2wrap.S | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)diff --git a/purgatory/arch/ppc64/v2wrap.S b/purgatory/arch/ppc64/v2wrap.S index 179ade9..3534080 100644 --- a/purgatory/arch/ppc64/v2wrap.S +++ b/purgatory/arch/ppc64/v2wrap.S@@ -116,9 +116,17 @@ master: stw 7,0x5c(4) # and patch it into the kernel mr 3,16 # restore dt address + mfmsr 5 + andi. 10,5,1 # test MSR_LE + bne little_endian + + li 5,0 # r5 will be 0 for kernel + mtctr 4 # prepare branch to + bctr # start kernel + +little_endian: # book3s-only mtsrr0 4 # prepare branch to - mfmsr 5 clrrdi 5,5,1 # clear MSR_LE mtsrr1 5-- 2.1.4 _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec