Merge branches 'fixes' and 'misc' into for-linus

1 files changed, 125 insertions, 68 deletions

diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index bfbad08a1207..49d8422767b4 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -57,7 +57,7 @@ system_call_common:
 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 BEGIN_FTR_SECTION
 	extrdi.	r10, r12, 1, (63-MSR_TS_T_LG) /* transaction active? */
-	bne	tabort_syscall
+	bne	.Ltabort_syscall
 END_FTR_SECTION_IFSET(CPU_FTR_TM)
 #endif
 	andi.	r10,r12,MSR_PR
@@ -143,6 +143,7 @@ END_FW_FTR_SECTION_IFSET(FW_FEATURE_SPLPAR)
 	mtmsrd	r11,1
 #endif /* CONFIG_PPC_BOOK3E */
 
+system_call:			/* label this so stack traces look sane */
 	/* We do need to set SOFTE in the stack frame or the return
 	 * from interrupt will be painful
 	 */
@@ -152,11 +153,11 @@ END_FW_FTR_SECTION_IFSET(FW_FEATURE_SPLPAR)
 	CURRENT_THREAD_INFO(r11, r1)
 	ld	r10,TI_FLAGS(r11)
 	andi.	r11,r10,_TIF_SYSCALL_DOTRACE
-	bne	syscall_dotrace		/* does not return */
+	bne	.Lsyscall_dotrace		/* does not return */
 	cmpldi	0,r0,NR_syscalls
-	bge-	syscall_enosys
+	bge-	.Lsyscall_enosys
 
-system_call:			/* label this so stack traces look sane */
+.Lsyscall:
 /*
  * Need to vector to 32 Bit or default sys_call_table here,
  * based on caller's run-mode / personality.
@@ -185,8 +186,20 @@ system_call:			/* label this so stack traces look sane */
 #ifdef CONFIG_PPC_BOOK3S
 	/* No MSR:RI on BookE */
 	andi.	r10,r8,MSR_RI
-	beq-	unrecov_restore
+	beq-	.Lunrecov_restore
 #endif
+
+/*
+ * This is a few instructions into the actual syscall exit path (which actually
+ * starts at .Lsyscall_exit) to cater to kprobe blacklisting and to reduce the
+ * number of visible symbols for profiling purposes.
+ *
+ * We can probe from system_call until this point as MSR_RI is set. But once it
+ * is cleared below, we won't be able to take a trap.
+ *
+ * This is blacklisted from kprobes further below with _ASM_NOKPROBE_SYMBOL().
+ */
+system_call_exit:
 	/*
 	 * Disable interrupts so current_thread_info()->flags can't change,
 	 * and so that we don't get interrupted after loading SRR0/1.
@@ -208,31 +221,21 @@ system_call:			/* label this so stack traces look sane */
 	ld	r9,TI_FLAGS(r12)
 	li	r11,-MAX_ERRNO
 	andi.	r0,r9,(_TIF_SYSCALL_DOTRACE|_TIF_SINGLESTEP|_TIF_USER_WORK_MASK|_TIF_PERSYSCALL_MASK)
-	bne-	syscall_exit_work
+	bne-	.Lsyscall_exit_work
 
-	andi.	r0,r8,MSR_FP
-	beq 2f
+	/* If MSR_FP and MSR_VEC are set in user msr, then no need to restore */
+	li	r7,MSR_FP
 #ifdef CONFIG_ALTIVEC
-	andis.	r0,r8,MSR_VEC@h
-	bne	3f
-#endif
-2:	addi    r3,r1,STACK_FRAME_OVERHEAD
-#ifdef CONFIG_PPC_BOOK3S
-	li	r10,MSR_RI
-	mtmsrd	r10,1		/* Restore RI */
-#endif
-	bl	restore_math
-#ifdef CONFIG_PPC_BOOK3S
-	li	r11,0
-	mtmsrd	r11,1
+	oris	r7,r7,MSR_VEC@h
 #endif
-	ld	r8,_MSR(r1)
-	ld	r3,RESULT(r1)
-	li	r11,-MAX_ERRNO
+	and	r0,r8,r7
+	cmpd	r0,r7
+	bne	.Lsyscall_restore_math
+.Lsyscall_restore_math_cont:
 
-3:	cmpld	r3,r11
+	cmpld	r3,r11
 	ld	r5,_CCR(r1)
-	bge-	syscall_error
+	bge-	.Lsyscall_error
 .Lsyscall_error_cont:
 	ld	r7,_NIP(r1)
 BEGIN_FTR_SECTION
@@ -258,14 +261,48 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
 	RFI
 	b	.	/* prevent speculative execution */
 
-syscall_error:	
+.Lsyscall_error:
 	oris	r5,r5,0x1000	/* Set SO bit in CR */
 	neg	r3,r3
 	std	r5,_CCR(r1)
 	b	.Lsyscall_error_cont
-	
+
+.Lsyscall_restore_math:
+	/*
+	 * Some initial tests from restore_math to avoid the heavyweight
+	 * C code entry and MSR manipulations.
+	 */
+	LOAD_REG_IMMEDIATE(r0, MSR_TS_MASK)
+	and.	r0,r0,r8
+	bne	1f
+
+	ld	r7,PACACURRENT(r13)
+	lbz	r0,THREAD+THREAD_LOAD_FP(r7)
+#ifdef CONFIG_ALTIVEC
+	lbz	r6,THREAD+THREAD_LOAD_VEC(r7)
+	add	r0,r0,r6
+#endif
+	cmpdi	r0,0
+	beq	.Lsyscall_restore_math_cont
+
+1:	addi    r3,r1,STACK_FRAME_OVERHEAD
+#ifdef CONFIG_PPC_BOOK3S
+	li	r10,MSR_RI
+	mtmsrd	r10,1		/* Restore RI */
+#endif
+	bl	restore_math
+#ifdef CONFIG_PPC_BOOK3S
+	li	r11,0
+	mtmsrd	r11,1
+#endif
+	/* Restore volatiles, reload MSR from updated one */
+	ld	r8,_MSR(r1)
+	ld	r3,RESULT(r1)
+	li	r11,-MAX_ERRNO
+	b	.Lsyscall_restore_math_cont
+
 /* Traced system call support */
-syscall_dotrace:
+.Lsyscall_dotrace:
 	bl	save_nvgprs
 	addi	r3,r1,STACK_FRAME_OVERHEAD
 	bl	do_syscall_trace_enter
@@ -286,23 +323,23 @@ syscall_dotrace:
 	ld	r7,GPR7(r1)
 	ld	r8,GPR8(r1)
 
-	/* Repopulate r9 and r10 for the system_call path */
+	/* Repopulate r9 and r10 for the syscall path */
 	addi	r9,r1,STACK_FRAME_OVERHEAD
 	CURRENT_THREAD_INFO(r10, r1)
 	ld	r10,TI_FLAGS(r10)
 
 	cmpldi	r0,NR_syscalls
-	blt+	system_call
+	blt+	.Lsyscall
 
 	/* Return code is already in r3 thanks to do_syscall_trace_enter() */
 	b	.Lsyscall_exit
 
 
-syscall_enosys:
+.Lsyscall_enosys:
 	li	r3,-ENOSYS
 	b	.Lsyscall_exit
 	
-syscall_exit_work:
+.Lsyscall_exit_work:
 #ifdef CONFIG_PPC_BOOK3S
 	li	r10,MSR_RI
 	mtmsrd	r10,1		/* Restore RI */
@@ -362,7 +399,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
 	b	ret_from_except
 
 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
-tabort_syscall:
+.Ltabort_syscall:
 	/* Firstly we need to enable TM in the kernel */
 	mfmsr	r10
 	li	r9, 1
@@ -388,6 +425,8 @@ tabort_syscall:
 	rfid
 	b	.	/* prevent speculative execution */
 #endif
+_ASM_NOKPROBE_SYMBOL(system_call_common);
+_ASM_NOKPROBE_SYMBOL(system_call_exit);
 
 /* Save non-volatile GPRs, if not already saved. */
 _GLOBAL(save_nvgprs)
@@ -398,6 +437,7 @@ _GLOBAL(save_nvgprs)
 	clrrdi	r0,r11,1
 	std	r0,_TRAP(r1)
 	blr
+_ASM_NOKPROBE_SYMBOL(save_nvgprs);
 
 	
 /*
@@ -488,33 +528,30 @@ _GLOBAL(_switch)
 	std	r23,_CCR(r1)
 	std	r1,KSP(r3)	/* Set old stack pointer */
 
-#ifdef CONFIG_SMP
-	/* We need a sync somewhere here to make sure that if the
-	 * previous task gets rescheduled on another CPU, it sees all
-	 * stores it has performed on this one.
+	/*
+	 * On SMP kernels, care must be taken because a task may be
+	 * scheduled off CPUx and on to CPUy. Memory ordering must be
+	 * considered.
+	 *
+	 * Cacheable stores on CPUx will be visible when the task is
+	 * scheduled on CPUy by virtue of the core scheduler barriers
+	 * (see "Notes on Program-Order guarantees on SMP systems." in
+	 * kernel/sched/core.c).
+	 *
+	 * Uncacheable stores in the case of involuntary preemption must
+	 * be taken care of. The smp_mb__before_spin_lock() in __schedule()
+	 * is implemented as hwsync on powerpc, which orders MMIO too. So
+	 * long as there is an hwsync in the context switch path, it will
+	 * be executed on the source CPU after the task has performed
+	 * all MMIO ops on that CPU, and on the destination CPU before the
+	 * task performs any MMIO ops there.
 	 */
-	sync
-#endif /* CONFIG_SMP */
 
 	/*
-	 * If we optimise away the clear of the reservation in system
-	 * calls because we know the CPU tracks the address of the
-	 * reservation, then we need to clear it here to cover the
-	 * case that the kernel context switch path has no larx
-	 * instructions.
+	 * The kernel context switch path must contain a spin_lock,
+	 * which contains larx/stcx, which will clear any reservation
+	 * of the task being switched.
 	 */
-BEGIN_FTR_SECTION
-	ldarx	r6,0,r1
-END_FTR_SECTION_IFSET(CPU_FTR_STCX_CHECKS_ADDRESS)
-
-BEGIN_FTR_SECTION
-/*
- * A cp_abort (copy paste abort) here ensures that when context switching, a
- * copy from one process can't leak into the paste of another.
- */
-	PPC_CP_ABORT
-END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)
-
 #ifdef CONFIG_PPC_BOOK3S
 /* Cancel all explict user streams as they will have no use after context
  * switch and will stop the HW from creating streams itself
@@ -583,6 +620,14 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_1T_SEGMENT)
 	   top of the kernel stack. */
 	addi	r7,r7,THREAD_SIZE-SWITCH_FRAME_SIZE
 
+	/*
+	 * PMU interrupts in radix may come in here. They will use r1, not
+	 * PACAKSAVE, so this stack switch will not cause a problem. They
+	 * will store to the process stack, which may then be migrated to
+	 * another CPU. However the rq lock release on this CPU paired with
+	 * the rq lock acquire on the new CPU before the stack becomes
+	 * active on the new CPU, will order those stores.
+	 */
 	mr	r1,r8		/* start using new stack pointer */
 	std	r7,PACAKSAVE(r13)
 
@@ -763,11 +808,11 @@ restore:
 	ld	r5,SOFTE(r1)
 	lbz	r6,PACASOFTIRQEN(r13)
 	cmpwi	cr0,r5,0
-	beq	restore_irq_off
+	beq	.Lrestore_irq_off
 
 	/* We are enabling, were we already enabled ? Yes, just return */
 	cmpwi	cr0,r6,1
-	beq	cr0,do_restore
+	beq	cr0,.Ldo_restore
 
 	/*
 	 * We are about to soft-enable interrupts (we are hard disabled
@@ -776,14 +821,14 @@ restore:
 	 */
 	lbz	r0,PACAIRQHAPPENED(r13)
 	cmpwi	cr0,r0,0
-	bne-	restore_check_irq_replay
+	bne-	.Lrestore_check_irq_replay
 
 	/*
 	 * Get here when nothing happened while soft-disabled, just
 	 * soft-enable and move-on. We will hard-enable as a side
 	 * effect of rfi
 	 */
-restore_no_replay:
+.Lrestore_no_replay:
 	TRACE_ENABLE_INTS
 	li	r0,1
 	stb	r0,PACASOFTIRQEN(r13);
@@ -791,7 +836,7 @@ restore_no_replay:
 	/*
 	 * Final return path. BookE is handled in a different file
 	 */
-do_restore:
+.Ldo_restore:
 #ifdef CONFIG_PPC_BOOK3E
 	b	exception_return_book3e
 #else
@@ -825,7 +870,7 @@ fast_exception_return:
 	REST_8GPRS(5, r1)
 
 	andi.	r0,r3,MSR_RI
-	beq-	unrecov_restore
+	beq-	.Lunrecov_restore
 
 	/* Load PPR from thread struct before we clear MSR:RI */
 BEGIN_FTR_SECTION
@@ -883,7 +928,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
 	 * make sure that in this case, we also clear PACA_IRQ_HARD_DIS
 	 * or that bit can get out of sync and bad things will happen
 	 */
-restore_irq_off:
+.Lrestore_irq_off:
 	ld	r3,_MSR(r1)
 	lbz	r7,PACAIRQHAPPENED(r13)
 	andi.	r0,r3,MSR_EE
@@ -893,13 +938,13 @@ restore_irq_off:
 1:	li	r0,0
 	stb	r0,PACASOFTIRQEN(r13);
 	TRACE_DISABLE_INTS
-	b	do_restore
+	b	.Ldo_restore
 
 	/*
 	 * Something did happen, check if a re-emit is needed
 	 * (this also clears paca->irq_happened)
 	 */
-restore_check_irq_replay:
+.Lrestore_check_irq_replay:
 	/* XXX: We could implement a fast path here where we check
 	 * for irq_happened being just 0x01, in which case we can
 	 * clear it and return. That means that we would potentially
@@ -909,7 +954,7 @@ restore_check_irq_replay:
 	 */
 	bl	__check_irq_replay
 	cmpwi	cr0,r3,0
- 	beq	restore_no_replay
+	beq	.Lrestore_no_replay
  
 	/*
 	 * We need to re-emit an interrupt. We do so by re-using our
@@ -958,10 +1003,18 @@ restore_check_irq_replay:
 #endif /* CONFIG_PPC_DOORBELL */
 1:	b	ret_from_except /* What else to do here ? */
  
-unrecov_restore:
+.Lunrecov_restore:
 	addi	r3,r1,STACK_FRAME_OVERHEAD
 	bl	unrecoverable_exception
-	b	unrecov_restore
+	b	.Lunrecov_restore
+
+_ASM_NOKPROBE_SYMBOL(ret_from_except);
+_ASM_NOKPROBE_SYMBOL(ret_from_except_lite);
+_ASM_NOKPROBE_SYMBOL(resume_kernel);
+_ASM_NOKPROBE_SYMBOL(fast_exc_return_irq);
+_ASM_NOKPROBE_SYMBOL(restore);
+_ASM_NOKPROBE_SYMBOL(fast_exception_return);
+
 
 #ifdef CONFIG_PPC_RTAS
 /*
@@ -1038,6 +1091,8 @@ _GLOBAL(enter_rtas)
         rldicr  r9,r9,MSR_SF_LG,(63-MSR_SF_LG)
 	ori	r9,r9,MSR_IR|MSR_DR|MSR_FE0|MSR_FE1|MSR_FP|MSR_RI|MSR_LE
 	andc	r6,r0,r9
+
+__enter_rtas:
 	sync				/* disable interrupts so SRR0/1 */
 	mtmsrd	r0			/* don't get trashed */
 
@@ -1074,6 +1129,8 @@ rtas_return_loc:
 	mtspr	SPRN_SRR1,r4
 	rfid
 	b	.	/* prevent speculative execution */
+_ASM_NOKPROBE_SYMBOL(__enter_rtas)
+_ASM_NOKPROBE_SYMBOL(rtas_return_loc)
 
 	.align	3
 1:	.llong	rtas_restore_regs