3 files changed, 38 insertions, 6 deletions

diff --git a/arch/arm/common/Makefile b/arch/arm/common/Makefile
index b070671033ae..9ec273188ccb 100644
--- a/arch/arm/common/Makefile
+++ b/arch/arm/common/Makefile
@@ -11,4 +11,4 @@ obj-$(CONFIG_SHARP_PARAM)	+= sharpsl_param.o
 obj-$(CONFIG_SHARP_SCOOP)       += scoop.o
 obj-$(CONFIG_PCI_HOST_ITE8152)  += it8152.o
 obj-$(CONFIG_ARM_TIMER_SP804)   += timer-sp.o
-obj-$(CONFIG_MCPM)              += mcpm_head.o mcpm_entry.o
+obj-$(CONFIG_MCPM)              += mcpm_head.o mcpm_entry.o vlock.o
diff --git a/arch/arm/common/mcpm_head.S b/arch/arm/common/mcpm_head.S
index 7d729bd72674..8178705c4b24 100644
--- a/arch/arm/common/mcpm_head.S
+++ b/arch/arm/common/mcpm_head.S
@@ -16,6 +16,8 @@
 #include <linux/linkage.h>
 #include <asm/mcpm.h>
 
+#include "vlock.h"
+
 .if MCPM_SYNC_CLUSTER_CPUS
 .error "cpus must be the first member of struct mcpm_sync_struct"
 .endif
@@ -69,10 +71,11 @@ ENTRY(mcpm_entry_point)
          * position independent way.
          */
         adr     r5, 3f
-        ldmia   r5, {r6, r7, r8}
+        ldmia   r5, {r6, r7, r8, r11}
         add     r6, r5, r6                      @ r6 = mcpm_entry_vectors
         ldr     r7, [r5, r7]                    @ r7 = mcpm_power_up_setup_phys
         add     r8, r5, r8                      @ r8 = mcpm_sync
+        add     r11, r5, r11                    @ r11 = first_man_locks
 
         mov     r0, #MCPM_SYNC_CLUSTER_SIZE
         mla     r8, r0, r10, r8                 @ r8 = sync cluster base
@@ -86,13 +89,22 @@ ENTRY(mcpm_entry_point)
         @ At this point, the cluster cannot unexpectedly enter the GOING_DOWN
         @ state, because there is at least one active CPU (this CPU).
 
-        @ Note: the following is racy as another CPU might be testing
-        @ the same flag at the same moment.  That'll be fixed later.
+        mov     r0, #VLOCK_SIZE
+        mla     r11, r0, r10, r11               @ r11 = cluster first man lock
+        mov     r0, r11
+        mov     r1, r9                          @ cpu
+        bl      vlock_trylock                   @ implies DMB
+
+        cmp     r0, #0                          @ failed to get the lock?
+        bne     mcpm_setup_wait         @ wait for cluster setup if so
+
         ldrb    r0, [r8, #MCPM_SYNC_CLUSTER_CLUSTER]
         cmp     r0, #CLUSTER_UP                 @ cluster already up?
         bne     mcpm_setup                      @ if not, set up the cluster
 
-        @ Otherwise, skip setup:
+        @ Otherwise, release the first man lock and skip setup:
+        mov     r0, r11
+        bl      vlock_unlock
         b       mcpm_setup_complete
 
 mcpm_setup:
@@ -142,6 +154,19 @@ mcpm_setup_leave:
         dsb
         sev
 
+        mov     r0, r11
+        bl      vlock_unlock    @ implies DMB
+        b       mcpm_setup_complete
+
+        @ In the contended case, non-first men wait here for cluster setup
+        @ to complete:
+mcpm_setup_wait:
+        ldrb    r0, [r8, #MCPM_SYNC_CLUSTER_CLUSTER]
+        cmp     r0, #CLUSTER_UP
+        wfene
+        bne     mcpm_setup_wait
+        dmb
+
 mcpm_setup_complete:
         @ If a platform-specific CPU setup hook is needed, it is
         @ called from here.
@@ -173,11 +198,17 @@ mcpm_entry_gated:
 3:      .word   mcpm_entry_vectors - .
         .word   mcpm_power_up_setup_phys - 3b
         .word   mcpm_sync - 3b
+        .word   first_man_locks - 3b
 
 ENDPROC(mcpm_entry_point)
 
         .bss
-        .align  5
+
+        .align  CACHE_WRITEBACK_ORDER
+        .type   first_man_locks, #object
+first_man_locks:
+        .space  VLOCK_SIZE * MAX_NR_CLUSTERS
+        .align  CACHE_WRITEBACK_ORDER
 
         .type   mcpm_entry_vectors, #object
 ENTRY(mcpm_entry_vectors)
diff --git a/arch/arm/kernel/asm-offsets.c b/arch/arm/kernel/asm-offsets.c
index 1bed82a0a9e0..3f088225e71c 100644
--- a/arch/arm/kernel/asm-offsets.c
+++ b/arch/arm/kernel/asm-offsets.c
@@ -150,6 +150,7 @@ int main(void)
   DEFINE(DMA_TO_DEVICE,         DMA_TO_DEVICE);
   DEFINE(DMA_FROM_DEVICE,       DMA_FROM_DEVICE);
   BLANK();
+  DEFINE(CACHE_WRITEBACK_ORDER, __CACHE_WRITEBACK_ORDER);
   DEFINE(CACHE_WRITEBACK_GRANULE, __CACHE_WRITEBACK_GRANULE);
   BLANK();
 #ifdef CONFIG_KVM_ARM_HOST