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Commit 94a6df25 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'powerpc-4.12-7' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux 

Pull powerpc fixes from Michael Ellerman:
 "Some more powerpc fixes for 4.12. Most of these actually came in last
  week but got held up for some more testing.

   - three fixes for kprobes/ftrace/livepatch interactions.

   - properly handle data breakpoints when using the Radix MMU.

   - fix for perf sampling of registers during call_usermodehelper().

   - properly initialise the thread_info on our emergency stacks

   - add an explicit flush when doing TLB invalidations for a process
     using NPU2.

  Thanks to: Alistair Popple, Naveen N. Rao, Nicholas Piggin, Ravi
  Bangoria, Masami Hiramatsu"

* tag 'powerpc-4.12-7' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/64: Initialise thread_info for emergency stacks
  powerpc/powernv/npu-dma: Add explicit flush when sending an ATSD
  powerpc/perf: Fix oops when kthread execs user process
  powerpc/64s: Handle data breakpoints in Radix mode
  powerpc/kprobes: Skip livepatch_handler() for jprobes
  powerpc/ftrace: Pass the correct stack pointer for DYNAMIC_FTRACE_WITH_REGS
  powerpc/kprobes: Pause function_graph tracing during jprobes handling
parents cd5545ae 34f19ff1

arch/powerpc/include/asm/kprobes.h

+1 −0
Original line number Diff line number Diff line
@@ -103,6 +103,7 @@ extern int kprobe_exceptions_notify(struct notifier_block *self, 
extern int kprobe_fault_handler(struct pt_regs *regs, int trapnr);

extern int kprobe_handler(struct pt_regs *regs);

extern int kprobe_post_handler(struct pt_regs *regs);

extern int is_current_kprobe_addr(unsigned long addr);

#ifdef CONFIG_KPROBES_ON_FTRACE

extern int skip_singlestep(struct kprobe *p, struct pt_regs *regs,

			   struct kprobe_ctlblk *kcb);

arch/powerpc/kernel/exceptions-64s.S

+7 −4
Original line number Diff line number Diff line
@@ -1411,10 +1411,8 @@ USE_TEXT_SECTION() 
	.balign	IFETCH_ALIGN_BYTES

do_hash_page:

#ifdef CONFIG_PPC_STD_MMU_64

	andis.	r0,r4,0xa410		/* weird error? */

	andis.	r0,r4,0xa450		/* weird error? */

	bne-	handle_page_fault	/* if not, try to insert a HPTE */

	andis.  r0,r4,DSISR_DABRMATCH@h

	bne-    handle_dabr_fault

	CURRENT_THREAD_INFO(r11, r1)

	lwz	r0,TI_PREEMPT(r11)	/* If we're in an "NMI" */

	andis.	r0,r0,NMI_MASK@h	/* (i.e. an irq when soft-disabled) */
@@ -1438,11 +1436,16 @@ do_hash_page: 


	/* Error */

	blt-	13f



	/* Reload DSISR into r4 for the DABR check below */

	ld      r4,_DSISR(r1)

#endif /* CONFIG_PPC_STD_MMU_64 */



/* Here we have a page fault that hash_page can't handle. */

handle_page_fault:

11:	ld	r4,_DAR(r1)

11:	andis.  r0,r4,DSISR_DABRMATCH@h

	bne-    handle_dabr_fault

	ld	r4,_DAR(r1)

	ld	r5,_DSISR(r1)

	addi	r3,r1,STACK_FRAME_OVERHEAD

	bl	do_page_fault

arch/powerpc/kernel/kprobes.c

+17 −0
Original line number Diff line number Diff line
@@ -43,6 +43,12 @@ DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); 


struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}};



int is_current_kprobe_addr(unsigned long addr)

{

	struct kprobe *p = kprobe_running();

	return (p && (unsigned long)p->addr == addr) ? 1 : 0;

}



bool arch_within_kprobe_blacklist(unsigned long addr)

{

	return  (addr >= (unsigned long)__kprobes_text_start &&
@@ -617,6 +623,15 @@ int setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) 
	regs->gpr[2] = (unsigned long)(((func_descr_t *)jp->entry)->toc);

#endif



	/*

	 * jprobes use jprobe_return() which skips the normal return

	 * path of the function, and this messes up the accounting of the

	 * function graph tracer.

	 *

	 * Pause function graph tracing while performing the jprobe function.

	 */

	pause_graph_tracing();



	return 1;

}

NOKPROBE_SYMBOL(setjmp_pre_handler);
@@ -642,6 +657,8 @@ int longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) 
	 * saved regs...

	 */

	memcpy(regs, &kcb->jprobe_saved_regs, sizeof(struct pt_regs));

	/* It's OK to start function graph tracing again */

	unpause_graph_tracing();

	preempt_enable_no_resched();

	return 1;

}

arch/powerpc/kernel/setup_64.c

+28 −3
Original line number Diff line number Diff line
@@ -615,6 +615,24 @@ void __init exc_lvl_early_init(void) 
}

#endif



/*

 * Emergency stacks are used for a range of things, from asynchronous

 * NMIs (system reset, machine check) to synchronous, process context.

 * We set preempt_count to zero, even though that isn't necessarily correct. To

 * get the right value we'd need to copy it from the previous thread_info, but

 * doing that might fault causing more problems.

 * TODO: what to do with accounting?

 */

static void emerg_stack_init_thread_info(struct thread_info *ti, int cpu)

{

	ti->task = NULL;

	ti->cpu = cpu;

	ti->preempt_count = 0;

	ti->local_flags = 0;

	ti->flags = 0;

	klp_init_thread_info(ti);

}



/*

 * Stack space used when we detect a bad kernel stack pointer, and

 * early in SMP boots before relocation is enabled. Exclusive emergency
@@ -633,24 +651,31 @@ void __init emergency_stack_init(void) 
	 * Since we use these as temporary stacks during secondary CPU

	 * bringup, we need to get at them in real mode. This means they

	 * must also be within the RMO region.

	 *

	 * The IRQ stacks allocated elsewhere in this file are zeroed and

	 * initialized in kernel/irq.c. These are initialized here in order

	 * to have emergency stacks available as early as possible.

	 */

	limit = min(safe_stack_limit(), ppc64_rma_size);



	for_each_possible_cpu(i) {

		struct thread_info *ti;

		ti = __va(memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit));

		klp_init_thread_info(ti);

		memset(ti, 0, THREAD_SIZE);

		emerg_stack_init_thread_info(ti, i);

		paca[i].emergency_sp = (void *)ti + THREAD_SIZE;



#ifdef CONFIG_PPC_BOOK3S_64

		/* emergency stack for NMI exception handling. */

		ti = __va(memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit));

		klp_init_thread_info(ti);

		memset(ti, 0, THREAD_SIZE);

		emerg_stack_init_thread_info(ti, i);

		paca[i].nmi_emergency_sp = (void *)ti + THREAD_SIZE;



		/* emergency stack for machine check exception handling. */

		ti = __va(memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit));

		klp_init_thread_info(ti);

		memset(ti, 0, THREAD_SIZE);

		emerg_stack_init_thread_info(ti, i);

		paca[i].mc_emergency_sp = (void *)ti + THREAD_SIZE;

#endif

	}

arch/powerpc/kernel/trace/ftrace_64_mprofile.S

+46 −13
Original line number Diff line number Diff line
@@ -45,10 +45,14 @@ _GLOBAL(ftrace_caller) 
	stdu	r1,-SWITCH_FRAME_SIZE(r1)



	/* Save all gprs to pt_regs */

	SAVE_8GPRS(0,r1)

	SAVE_8GPRS(8,r1)

	SAVE_8GPRS(16,r1)

	SAVE_8GPRS(24,r1)

	SAVE_GPR(0, r1)

	SAVE_10GPRS(2, r1)

	SAVE_10GPRS(12, r1)

	SAVE_10GPRS(22, r1)



	/* Save previous stack pointer (r1) */

	addi	r8, r1, SWITCH_FRAME_SIZE

	std	r8, GPR1(r1)



	/* Load special regs for save below */

	mfmsr   r8
@@ -95,18 +99,44 @@ ftrace_call: 
	bl	ftrace_stub

	nop



	/* Load ctr with the possibly modified NIP */

	ld	r3, _NIP(r1)

	mtctr	r3

	/* Load the possibly modified NIP */

	ld	r15, _NIP(r1)



#ifdef CONFIG_LIVEPATCH

	cmpd	r14,r3		/* has NIP been altered? */

	cmpd	r14, r15	/* has NIP been altered? */

#endif



#if defined(CONFIG_LIVEPATCH) && defined(CONFIG_KPROBES_ON_FTRACE)

	/* NIP has not been altered, skip over further checks */

	beq	1f



	/* Check if there is an active kprobe on us */

	subi	r3, r14, 4

	bl	is_current_kprobe_addr

	nop



	/*

	 * If r3 == 1, then this is a kprobe/jprobe.

	 * else, this is livepatched function.

	 *

	 * The conditional branch for livepatch_handler below will use the

	 * result of this comparison. For kprobe/jprobe, we just need to branch to

	 * the new NIP, not call livepatch_handler. The branch below is bne, so we

	 * want CR0[EQ] to be true if this is a kprobe/jprobe. Which means we want

	 * CR0[EQ] = (r3 == 1).

	 */

	cmpdi	r3, 1

1:

#endif



	/* Load CTR with the possibly modified NIP */

	mtctr	r15



	/* Restore gprs */

	REST_8GPRS(0,r1)

	REST_8GPRS(8,r1)

	REST_8GPRS(16,r1)

	REST_8GPRS(24,r1)

	REST_GPR(0,r1)

	REST_10GPRS(2,r1)

	REST_10GPRS(12,r1)

	REST_10GPRS(22,r1)



	/* Restore possibly modified LR */

	ld	r0, _LINK(r1)
@@ -119,7 +149,10 @@ ftrace_call: 
	addi r1, r1, SWITCH_FRAME_SIZE



#ifdef CONFIG_LIVEPATCH

        /* Based on the cmpd above, if the NIP was altered handle livepatch */

        /*

	 * Based on the cmpd or cmpdi above, if the NIP was altered and we're

	 * not on a kprobe/jprobe, then handle livepatch.

	 */

	bne-	livepatch_handler

#endif