From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <4C64ED14.9070602@ozlabs.org> Date: Fri, 13 Aug 2010 16:58:28 +1000 From: Matt Evans MIME-Version: 1.0 To: linuxppc-dev@ozlabs.org Subject: [PATCH] powerpc: Initialise paca->kstack before early_setup_secondary Content-Type: text/plain; charset=ISO-8859-1 Cc: mjwolf@us.ibm.com List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , As early setup calls down to slb_initialize(), we must have kstack initialised before checking "should we add a bolted SLB entry for our kstack?" Failing to do so means stack access requires an SLB miss exception to refill an entry dynamically, if the stack isn't accessible via SLB(0) (kernel text & static data). It's not always allowable to take such a miss, and intermittent crashes will result. Primary CPUs don't have this issue; an SLB entry is not bolted for their stack anyway (as that lives within SLB(0)). This patch therefore only affects the init of secondaries. Signed-off-by: Matt Evans Cc: stable --- arch/powerpc/kernel/head_64.S | 6 +++--- 1 files changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S index 844a44b..4d6681d 100644 --- a/arch/powerpc/kernel/head_64.S +++ b/arch/powerpc/kernel/head_64.S @@ -572,9 +572,6 @@ __secondary_start: /* Set thread priority to MEDIUM */ HMT_MEDIUM - /* Do early setup for that CPU (stab, slb, hash table pointer) */ - bl .early_setup_secondary - /* Initialize the kernel stack. Just a repeat for iSeries. */ LOAD_REG_ADDR(r3, current_set) sldi r28,r24,3 /* get current_set[cpu#] */ @@ -582,6 +579,9 @@ __secondary_start: addi r1,r1,THREAD_SIZE-STACK_FRAME_OVERHEAD std r1,PACAKSAVE(r13) + /* Do early setup for that CPU (stab, slb, hash table pointer) */ + bl .early_setup_secondary + /* Clear backchain so we get nice backtraces */ li r7,0 mtlr r7 -- 1.7.0.4