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authorBenjamin Herrenschmidt <benh@kernel.crashing.org>2013-08-21 13:03:20 +1000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2013-08-27 17:43:50 +1000
commit13906db670a128864714c30c244b866dce119494 (patch)
tree3f615ce7648aa6b15cbd8ff8eaf2c51250f57cd9
parentee372bc1c6ab2f411d098337936ebb994af264c4 (diff)
downloadlinux-13906db670a128864714c30c244b866dce119494.tar.gz
powerpc/powernv: Return secondary CPUs to firmware on kexec
With OPAL v3 we can return secondary CPUs to firmware on kexec. This
allows firmware to do various cleanups making things generally more
reliable, and will enable the "new" kernel to call OPAL to perform
some reconfiguration tasks early on that can only be done while
all the CPUs are in firmware.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
-rw-r--r--arch/powerpc/include/asm/opal.h2
-rw-r--r--arch/powerpc/platforms/powernv/opal-wrappers.S1
-rw-r--r--arch/powerpc/platforms/powernv/setup.c11
3 files changed, 14 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/opal.h b/arch/powerpc/include/asm/opal.h
index 48ad6780c6d9..c5cd72833d6e 100644
--- a/arch/powerpc/include/asm/opal.h
+++ b/arch/powerpc/include/asm/opal.h
@@ -128,6 +128,7 @@ extern int opal_enter_rtas(struct rtas_args *args,
 #define OPAL_XSCOM_WRITE			66
 #define OPAL_LPC_READ				67
 #define OPAL_LPC_WRITE				68
+#define OPAL_RETURN_CPU				69
 
 #ifndef __ASSEMBLY__
 
@@ -646,6 +647,7 @@ int64_t opal_set_system_attention_led(uint8_t led_action);
 int64_t opal_pci_next_error(uint64_t phb_id, uint64_t *first_frozen_pe,
 			    uint16_t *pci_error_type, uint16_t *severity);
 int64_t opal_pci_poll(uint64_t phb_id);
+int64_t opal_return_cpu(void);
 
 int64_t opal_xscom_read(uint32_t gcid, uint32_t pcb_addr, uint64_t *val);
 int64_t opal_xscom_write(uint32_t gcid, uint32_t pcb_addr, uint64_t val);
diff --git a/arch/powerpc/platforms/powernv/opal-wrappers.S b/arch/powerpc/platforms/powernv/opal-wrappers.S
index 42c06fba3994..8f3844535fbb 100644
--- a/arch/powerpc/platforms/powernv/opal-wrappers.S
+++ b/arch/powerpc/platforms/powernv/opal-wrappers.S
@@ -115,3 +115,4 @@ OPAL_CALL(opal_xscom_read,			OPAL_XSCOM_READ);
 OPAL_CALL(opal_xscom_write,			OPAL_XSCOM_WRITE);
 OPAL_CALL(opal_lpc_read,			OPAL_LPC_READ);
 OPAL_CALL(opal_lpc_write,			OPAL_LPC_WRITE);
+OPAL_CALL(opal_return_cpu,			OPAL_RETURN_CPU);
diff --git a/arch/powerpc/platforms/powernv/setup.c b/arch/powerpc/platforms/powernv/setup.c
index 4ddb339700b9..e239dcfa224c 100644
--- a/arch/powerpc/platforms/powernv/setup.c
+++ b/arch/powerpc/platforms/powernv/setup.c
@@ -31,6 +31,7 @@
 #include <asm/xics.h>
 #include <asm/rtas.h>
 #include <asm/opal.h>
+#include <asm/kexec.h>
 
 #include "powernv.h"
 
@@ -153,6 +154,16 @@ static void pnv_shutdown(void)
 static void pnv_kexec_cpu_down(int crash_shutdown, int secondary)
 {
 	xics_kexec_teardown_cpu(secondary);
+
+	/* Return secondary CPUs to firmware on OPAL v3 */
+	if (firmware_has_feature(FW_FEATURE_OPALv3) && secondary) {
+		mb();
+		get_paca()->kexec_state = KEXEC_STATE_REAL_MODE;
+		mb();
+
+		/* Return the CPU to OPAL */
+		opal_return_cpu();
+	}
 }
 #endif /* CONFIG_KEXEC */