From: Alexey Kardashevskiy Date: Thu, 2 Mar 2017 06:41:24 +0000 (+1100) Subject: powerpc/powernv: Fix opal tracepoints with JUMP_LABEL=n X-Git-Tag: v4.11-rc2~37^2~7 X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=2a9c4f40ab2c281f95d41577ff0f7f78668feb73;p=linux.git 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 Signed-off-by: Alexey Kardashevskiy Signed-off-by: Michael Ellerman --- diff --git a/arch/powerpc/platforms/powernv/opal-wrappers.S b/arch/powerpc/platforms/powernv/opal-wrappers.S index 6693f75e93d1..da8a0f7a035c 100644 --- a/arch/powerpc/platforms/powernv/opal-wrappers.S +++ b/arch/powerpc/platforms/powernv/opal-wrappers.S @@ -39,8 +39,8 @@ opal_tracepoint_refcount: BEGIN_FTR_SECTION; \ b 1f; \ END_FTR_SECTION(0, 1); \ - ld r12,opal_tracepoint_refcount@toc(r2); \ - cmpdi r12,0; \ + ld r11,opal_tracepoint_refcount@toc(r2); \ + cmpdi r11,0; \ bne- LABEL; \ 1: