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author | Linus Torvalds <torvalds@linux-foundation.org> | 2017-06-23 17:53:16 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-06-23 17:53:16 -0700 |
commit | 94a6df251dd08c6436ebd6d10c68f03659148ce1 (patch) | |
tree | 51aca5d25d4bffa9860d8c1b1d96d3a64cd28a38 /arch/powerpc/kernel | |
parent | cd5545ae87ed9ca76dba7753b436713ce8df2872 (diff) | |
parent | 34f19ff1b5a0d11e46df479623d6936460105c9f (diff) | |
download | linux-94a6df251dd08c6436ebd6d10c68f03659148ce1.tar.bz2 |
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
Diffstat (limited to 'arch/powerpc/kernel')
-rw-r--r-- | arch/powerpc/kernel/exceptions-64s.S | 11 | ||||
-rw-r--r-- | arch/powerpc/kernel/kprobes.c | 17 | ||||
-rw-r--r-- | arch/powerpc/kernel/setup_64.c | 31 | ||||
-rw-r--r-- | arch/powerpc/kernel/trace/ftrace_64_mprofile.S | 59 |
4 files changed, 98 insertions, 20 deletions
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index ae418b85c17c..b886795060fd 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -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 diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c index fc4343514bed..01addfb0ed0a 100644 --- a/arch/powerpc/kernel/kprobes.c +++ b/arch/powerpc/kernel/kprobes.c @@ -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; } diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c index a8c1f99e9607..4640f6d64f8b 100644 --- a/arch/powerpc/kernel/setup_64.c +++ b/arch/powerpc/kernel/setup_64.c @@ -616,6 +616,24 @@ 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 * stack for machine checks. @@ -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 } diff --git a/arch/powerpc/kernel/trace/ftrace_64_mprofile.S b/arch/powerpc/kernel/trace/ftrace_64_mprofile.S index 7c933a99f5d5..c98e90b4ea7b 100644 --- a/arch/powerpc/kernel/trace/ftrace_64_mprofile.S +++ b/arch/powerpc/kernel/trace/ftrace_64_mprofile.S @@ -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 |