]> git.proxmox.com Git - mirror_ubuntu-eoan-kernel.git/commit
powerpc/powernv: Fix opal tracepoints with JUMP_LABEL=n
authorAlexey Kardashevskiy <aik@ozlabs.ru>
Thu, 2 Mar 2017 06:41:24 +0000 (17:41 +1100)
committerMichael Ellerman <mpe@ellerman.id.au>
Sat, 4 Mar 2017 10:48:49 +0000 (21:48 +1100)
commit2a9c4f40ab2c281f95d41577ff0f7f78668feb73
tree1c873cdeb3dd710e6173df90f5e877ce377095b7
parent3fb66a70a4ae886445743354e4b60e54058bb3ff
powerpc/powernv: Fix opal tracepoints with JUMP_LABEL=n

The recent commit to allow calling OPAL calls in real mode, commit
ab9bad0ead9a ("powerpc/powernv: Remove separate entry for OPAL real mode
calls"), introduced a bug when CONFIG_JUMP_LABEL=n.

The commit moved the "mfmsr r12" prior to the call to OPAL_BRANCH, but
we missed that OPAL_BRANCH clobbers r12 when jump labels are disabled.
This leads to us using the tracepoint refcount as the MSR value,
typically zero, and saving that into PACASAVEDMSR. When we return from
OPAL we use that value as the MSR value for rfid, meaning we switch to
32-bit BE real mode - hilarity ensues.

Fix it by using r11 in OPAL_BRANCH, which is not live at the time the
macro is used in OPAL_CALL.

Fixes: ab9bad0ead9a ("powerpc/powernv: Remove separate entry for OPAL real mode calls")
Suggested-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
arch/powerpc/platforms/powernv/opal-wrappers.S