path: root/arch/powerpc/kernel/head_64.S
diff options
authorBenjamin Herrenschmidt <benh@kernel.crashing.org>2011-09-19 18:27:58 +0000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2011-09-20 16:09:47 +1000
commit27f4488872d9ef2a4b9aa2be58fb0789d6c0ba84 (patch)
tree204a12bb5b61beda8df7b5eaa78499191cb28721 /arch/powerpc/kernel/head_64.S
parent344eb010b2e399069bac474a9fd0ba04908a2601 (diff)
powerpc/powernv: Add OPAL takeover from PowerVM
On machines supporting the OPAL firmware version 1, the system is initially booted under pHyp. We then use a special hypercall to verify if OPAL is available and if it is, we then trigger a "takeover" which disables pHyp and loads the OPAL runtime firmware, giving control to the kernel in hypervisor mode. This patch add the necessary code to detect that the OPAL takeover capability is present when running under PowerVM (aka pHyp) and perform said takeover to get hypervisor control of the processor. To perform the takeover, we must first use RTAS (within Open Firmware runtime environment) to start all processors & threads, in order to give control to OPAL on all of them. We then call the takeover hypercall on everybody, OPAL will re-enter the kernel main entry point passing it a flat device-tree. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/kernel/head_64.S')
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S
index e708abe576d..dea8191253d 100644
--- a/arch/powerpc/kernel/head_64.S
+++ b/arch/powerpc/kernel/head_64.S
@@ -51,6 +51,10 @@
* For pSeries or server processors:
* 1. The MMU is off & open firmware is running in real mode.
* 2. The kernel is entered at __start
+ * -or- For OPAL entry:
+ * 1. The MMU is off, processor in HV mode, primary CPU enters at 0
+ * with device-tree in gpr3
+ * 2. Secondary processors enter at 0x60 with PIR in gpr3
* For iSeries:
* 1. The MMU is on (as it always is for iSeries)