Re: [PATCH 5/6] powerpc/livepatch: Add livepatch stack to struct thread_info

2016-03-31 Thread Balbir Singh 


On 24/03/16 22:04, Michael Ellerman wrote:
> In order to support live patching we need to maintain an alternate
> stack of TOC & LR values. We use the base of the stack for this, and
> store the "live patch stack pointer" in struct thread_info.
>
> Unlike the other fields of thread_info, we can not statically initialise
> that value, so it must be done at run time.
>
> This patch just adds the code to support that, it is not enabled until
> the next patch which actually adds live patch support.
>
> Signed-off-by: Michael Ellerman 
> ---
>  arch/powerpc/include/asm/livepatch.h   |  8 
>  arch/powerpc/include/asm/thread_info.h |  4 +++-
>  arch/powerpc/kernel/irq.c  |  3 +++
>  arch/powerpc/kernel/process.c  |  6 +-
>  arch/powerpc/kernel/setup_64.c | 17 ++---
>  5 files changed, 29 insertions(+), 9 deletions(-)
>
>

Acked-by: Balbir Singh

Re: [PATCH 5/6] powerpc/livepatch: Add livepatch stack to struct thread_info

2016-03-31 Thread Balbir Singh 


On 24/03/16 22:04, Michael Ellerman wrote:
> In order to support live patching we need to maintain an alternate
> stack of TOC & LR values. We use the base of the stack for this, and
> store the "live patch stack pointer" in struct thread_info.
>
> Unlike the other fields of thread_info, we can not statically initialise
> that value, so it must be done at run time.
>
> This patch just adds the code to support that, it is not enabled until
> the next patch which actually adds live patch support.
>
> Signed-off-by: Michael Ellerman 
> ---
>  arch/powerpc/include/asm/livepatch.h   |  8 
>  arch/powerpc/include/asm/thread_info.h |  4 +++-
>  arch/powerpc/kernel/irq.c  |  3 +++
>  arch/powerpc/kernel/process.c  |  6 +-
>  arch/powerpc/kernel/setup_64.c | 17 ++---
>  5 files changed, 29 insertions(+), 9 deletions(-)
>
>

Acked-by: Balbir Singh

Re: [PATCH 5/6] powerpc/livepatch: Add livepatch stack to struct thread_info

2016-03-28 Thread Balbir Singh 

>> At this point ti->livepatch_sp points to the next CPUs thread_info for 
>> softirq_ctx?
> Sorry I'm not sure what you mean.
>
> None of this relates to the current CPUs thread info.
Oh! I meant that klp_init_thread_info points to the end of (struct thread_info 
{} + 1) in the stack of the thread/task, but with the irq_contexts they are a 
separate array and not on stack
>>> diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
>>> index 3807fb05b6de..1b6cabb8e715 100644
>>> --- a/arch/powerpc/kernel/setup_64.c
>>> +++ b/arch/powerpc/kernel/setup_64.c
>>> @@ -69,6 +69,7 @@
>>>  #include 
>>>  #include 
>>>  #include 
>>> +#include 
>>>  
>>>  #ifdef DEBUG
>>>  #define DBG(fmt...) udbg_printf(fmt)
>>> @@ -667,16 +668,16 @@ static void __init emergency_stack_init(void)
>>> limit = min(safe_stack_limit(), ppc64_rma_size);
>>>  
>>> for_each_possible_cpu(i) {
>>> -   unsigned long sp;
>>> -   sp  = memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit);
>>> -   sp += THREAD_SIZE;
>>> -   paca[i].emergency_sp = __va(sp);
>>> +   struct thread_info *ti;
>>> +   ti = __va(memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit));
>>> +   klp_init_thread_info(ti);
>>> +   paca[i].emergency_sp = (void *)ti + THREAD_SIZE;
>>  
>> Does emergency_sp still end up 128 byte aligned after this?
> It should end up THREAD_SIZE aligned as before, due to the 
> memblock_alloc_base().
Yep.. I missed it.. so where is the space for ti? The stack is going to go grow 
downwards from ti+THREAD_SIZE
>>>  #ifdef CONFIG_PPC_BOOK3S_64
>>> /* emergency stack for machine check exception handling. */
>>> -   sp  = memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit);
>>> -   sp += THREAD_SIZE;
>>> -   paca[i].mc_emergency_sp = __va(sp);
>>> +   ti = __va(memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit));
>>> +   klp_init_thread_info(ti);
>> Do we care about live-patching in this context? Are we mixing per-thread and 
>> per-cpu contexts?
> Well we probably don't want to be doing live patching when we're on the
> emergency stacks. But we have no control over whether that happens so we have
> to support it.
>

OK.. I was wondering if the code will even work.. I wonder if the ftrace data 
structures will work in real mode, including the hash/etc.

Balbir

Re: [PATCH 5/6] powerpc/livepatch: Add livepatch stack to struct thread_info

2016-03-28 Thread Balbir Singh 

>> At this point ti->livepatch_sp points to the next CPUs thread_info for 
>> softirq_ctx?
> Sorry I'm not sure what you mean.
>
> None of this relates to the current CPUs thread info.
Oh! I meant that klp_init_thread_info points to the end of (struct thread_info 
{} + 1) in the stack of the thread/task, but with the irq_contexts they are a 
separate array and not on stack
>>> diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
>>> index 3807fb05b6de..1b6cabb8e715 100644
>>> --- a/arch/powerpc/kernel/setup_64.c
>>> +++ b/arch/powerpc/kernel/setup_64.c
>>> @@ -69,6 +69,7 @@
>>>  #include 
>>>  #include 
>>>  #include 
>>> +#include 
>>>  
>>>  #ifdef DEBUG
>>>  #define DBG(fmt...) udbg_printf(fmt)
>>> @@ -667,16 +668,16 @@ static void __init emergency_stack_init(void)
>>> limit = min(safe_stack_limit(), ppc64_rma_size);
>>>  
>>> for_each_possible_cpu(i) {
>>> -   unsigned long sp;
>>> -   sp  = memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit);
>>> -   sp += THREAD_SIZE;
>>> -   paca[i].emergency_sp = __va(sp);
>>> +   struct thread_info *ti;
>>> +   ti = __va(memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit));
>>> +   klp_init_thread_info(ti);
>>> +   paca[i].emergency_sp = (void *)ti + THREAD_SIZE;
>>  
>> Does emergency_sp still end up 128 byte aligned after this?
> It should end up THREAD_SIZE aligned as before, due to the 
> memblock_alloc_base().
Yep.. I missed it.. so where is the space for ti? The stack is going to go grow 
downwards from ti+THREAD_SIZE
>>>  #ifdef CONFIG_PPC_BOOK3S_64
>>> /* emergency stack for machine check exception handling. */
>>> -   sp  = memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit);
>>> -   sp += THREAD_SIZE;
>>> -   paca[i].mc_emergency_sp = __va(sp);
>>> +   ti = __va(memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit));
>>> +   klp_init_thread_info(ti);
>> Do we care about live-patching in this context? Are we mixing per-thread and 
>> per-cpu contexts?
> Well we probably don't want to be doing live patching when we're on the
> emergency stacks. But we have no control over whether that happens so we have
> to support it.
>

OK.. I was wondering if the code will even work.. I wonder if the ftrace data 
structures will work in real mode, including the hash/etc.

Balbir

Re: [PATCH 5/6] powerpc/livepatch: Add livepatch stack to struct thread_info

2016-03-28 Thread Michael Ellerman 
On Tue, 2016-03-29 at 10:58 +1100, Balbir Singh wrote:
> On 24/03/16 22:04, Michael Ellerman wrote:
> > diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
> > index 290559df1e8b..3cb46a3b1de7 100644
> > --- a/arch/powerpc/kernel/irq.c
> > +++ b/arch/powerpc/kernel/irq.c
> > @@ -66,6 +66,7 @@
> >  #include 
> >  #include 
> >  #include 
> > +#include 
> >  
> >  #ifdef CONFIG_PPC64
> >  #include 
> > @@ -607,10 +608,12 @@ void irq_ctx_init(void)
> > memset((void *)softirq_ctx[i], 0, THREAD_SIZE);
> > tp = softirq_ctx[i];
> > tp->cpu = i;
> > +   klp_init_thread_info(tp);

> At this point ti->livepatch_sp points to the next CPUs thread_info for 
> softirq_ctx?

Sorry I'm not sure what you mean.

None of this relates to the current CPUs thread info.

> > diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
> > index 3807fb05b6de..1b6cabb8e715 100644
> > --- a/arch/powerpc/kernel/setup_64.c
> > +++ b/arch/powerpc/kernel/setup_64.c
> > @@ -69,6 +69,7 @@
> >  #include 
> >  #include 
> >  #include 
> > +#include 
> >  
> >  #ifdef DEBUG
> >  #define DBG(fmt...) udbg_printf(fmt)
> > @@ -667,16 +668,16 @@ static void __init emergency_stack_init(void)
> > limit = min(safe_stack_limit(), ppc64_rma_size);
> >  
> > for_each_possible_cpu(i) {
> > -   unsigned long sp;
> > -   sp  = memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit);
> > -   sp += THREAD_SIZE;
> > -   paca[i].emergency_sp = __va(sp);
> > +   struct thread_info *ti;
> > +   ti = __va(memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit));
> > +   klp_init_thread_info(ti);
> > +   paca[i].emergency_sp = (void *)ti + THREAD_SIZE;
>  
> Does emergency_sp still end up 128 byte aligned after this?

It should end up THREAD_SIZE aligned as before, due to the 
memblock_alloc_base().

> >  #ifdef CONFIG_PPC_BOOK3S_64
> > /* emergency stack for machine check exception handling. */
> > -   sp  = memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit);
> > -   sp += THREAD_SIZE;
> > -   paca[i].mc_emergency_sp = __va(sp);
> > +   ti = __va(memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit));
> > +   klp_init_thread_info(ti);

> Do we care about live-patching in this context? Are we mixing per-thread and 
> per-cpu contexts?

Well we probably don't want to be doing live patching when we're on the
emergency stacks. But we have no control over whether that happens so we have
to support it.

cheers

Re: [PATCH 5/6] powerpc/livepatch: Add livepatch stack to struct thread_info

2016-03-28 Thread Michael Ellerman 
On Tue, 2016-03-29 at 10:58 +1100, Balbir Singh wrote:
> On 24/03/16 22:04, Michael Ellerman wrote:
> > diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
> > index 290559df1e8b..3cb46a3b1de7 100644
> > --- a/arch/powerpc/kernel/irq.c
> > +++ b/arch/powerpc/kernel/irq.c
> > @@ -66,6 +66,7 @@
> >  #include 
> >  #include 
> >  #include 
> > +#include 
> >  
> >  #ifdef CONFIG_PPC64
> >  #include 
> > @@ -607,10 +608,12 @@ void irq_ctx_init(void)
> > memset((void *)softirq_ctx[i], 0, THREAD_SIZE);
> > tp = softirq_ctx[i];
> > tp->cpu = i;
> > +   klp_init_thread_info(tp);

> At this point ti->livepatch_sp points to the next CPUs thread_info for 
> softirq_ctx?

Sorry I'm not sure what you mean.

None of this relates to the current CPUs thread info.

> > diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
> > index 3807fb05b6de..1b6cabb8e715 100644
> > --- a/arch/powerpc/kernel/setup_64.c
> > +++ b/arch/powerpc/kernel/setup_64.c
> > @@ -69,6 +69,7 @@
> >  #include 
> >  #include 
> >  #include 
> > +#include 
> >  
> >  #ifdef DEBUG
> >  #define DBG(fmt...) udbg_printf(fmt)
> > @@ -667,16 +668,16 @@ static void __init emergency_stack_init(void)
> > limit = min(safe_stack_limit(), ppc64_rma_size);
> >  
> > for_each_possible_cpu(i) {
> > -   unsigned long sp;
> > -   sp  = memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit);
> > -   sp += THREAD_SIZE;
> > -   paca[i].emergency_sp = __va(sp);
> > +   struct thread_info *ti;
> > +   ti = __va(memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit));
> > +   klp_init_thread_info(ti);
> > +   paca[i].emergency_sp = (void *)ti + THREAD_SIZE;
>  
> Does emergency_sp still end up 128 byte aligned after this?

It should end up THREAD_SIZE aligned as before, due to the 
memblock_alloc_base().

> >  #ifdef CONFIG_PPC_BOOK3S_64
> > /* emergency stack for machine check exception handling. */
> > -   sp  = memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit);
> > -   sp += THREAD_SIZE;
> > -   paca[i].mc_emergency_sp = __va(sp);
> > +   ti = __va(memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit));
> > +   klp_init_thread_info(ti);

> Do we care about live-patching in this context? Are we mixing per-thread and 
> per-cpu contexts?

Well we probably don't want to be doing live patching when we're on the
emergency stacks. But we have no control over whether that happens so we have
to support it.

cheers

Re: [PATCH 5/6] powerpc/livepatch: Add livepatch stack to struct thread_info

2016-03-28 Thread Balbir Singh 


On 24/03/16 22:04, Michael Ellerman wrote:
> In order to support live patching we need to maintain an alternate
> stack of TOC & LR values. We use the base of the stack for this, and
> store the "live patch stack pointer" in struct thread_info.
>
> Unlike the other fields of thread_info, we can not statically initialise
> that value, so it must be done at run time.
>
> This patch just adds the code to support that, it is not enabled until
> the next patch which actually adds live patch support.
>
> Signed-off-by: Michael Ellerman 
> ---
>  arch/powerpc/include/asm/livepatch.h   |  8 
>  arch/powerpc/include/asm/thread_info.h |  4 +++-
>  arch/powerpc/kernel/irq.c  |  3 +++
>  arch/powerpc/kernel/process.c  |  6 +-
>  arch/powerpc/kernel/setup_64.c | 17 ++---
>  5 files changed, 29 insertions(+), 9 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/livepatch.h 
> b/arch/powerpc/include/asm/livepatch.h
> index ad36e8e34fa1..a402f7f94896 100644
> --- a/arch/powerpc/include/asm/livepatch.h
> +++ b/arch/powerpc/include/asm/livepatch.h
> @@ -49,6 +49,14 @@ static inline unsigned long 
> klp_get_ftrace_location(unsigned long faddr)
>*/
>   return ftrace_location_range(faddr, faddr + 16);
>  }
> +
> +static inline void klp_init_thread_info(struct thread_info *ti)
> +{
> + /* + 1 to account for STACK_END_MAGIC */
> + ti->livepatch_sp = (unsigned long *)(ti + 1) + 1;
> +}
> +#else
> +static void klp_init_thread_info(struct thread_info *ti) { }
>  #endif /* CONFIG_LIVEPATCH */
>  
>  #endif /* _ASM_POWERPC_LIVEPATCH_H */
> diff --git a/arch/powerpc/include/asm/thread_info.h 
> b/arch/powerpc/include/asm/thread_info.h
> index 7efee4a3240b..8febc3f66d53 100644
> --- a/arch/powerpc/include/asm/thread_info.h
> +++ b/arch/powerpc/include/asm/thread_info.h
> @@ -43,7 +43,9 @@ struct thread_info {
>   int preempt_count;  /* 0 => preemptable,
>  <0 => BUG */
>   unsigned long   local_flags;/* private flags for thread */
> -
> +#ifdef CONFIG_LIVEPATCH
> + unsigned long *livepatch_sp;
> +#endif
>   /* low level flags - has atomic operations done on it */
>   unsigned long   flags cacheline_aligned_in_smp;
>  };
> diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
> index 290559df1e8b..3cb46a3b1de7 100644
> --- a/arch/powerpc/kernel/irq.c
> +++ b/arch/powerpc/kernel/irq.c
> @@ -66,6 +66,7 @@
>  #include 
>  #include 
>  #include 
> +#include 
>  
>  #ifdef CONFIG_PPC64
>  #include 
> @@ -607,10 +608,12 @@ void irq_ctx_init(void)
>   memset((void *)softirq_ctx[i], 0, THREAD_SIZE);
>   tp = softirq_ctx[i];
>   tp->cpu = i;
> + klp_init_thread_info(tp);
At this point ti->livepatch_sp points to the next CPUs thread_info for 
softirq_ctx?
>  
>   memset((void *)hardirq_ctx[i], 0, THREAD_SIZE);
>   tp = hardirq_ctx[i];
>   tp->cpu = i;
> + klp_init_thread_info(tp);
Same question here
>   }
>  }
>  
> diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
> index 612df305886b..c27215e6ef48 100644
> --- a/arch/powerpc/kernel/process.c
> +++ b/arch/powerpc/kernel/process.c
> @@ -55,6 +55,8 @@
>  #include 
>  #endif
>  #include 
> +#include 
> +
>  #include 
>  #include 
>  
> @@ -1400,13 +1402,15 @@ int copy_thread(unsigned long clone_flags, unsigned 
> long usp,
>   extern void ret_from_kernel_thread(void);
>   void (*f)(void);
>   unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
> + struct thread_info *ti = task_thread_info(p);
> +
> + klp_init_thread_info(ti);
>  
>   /* Copy registers */
>   sp -= sizeof(struct pt_regs);
>   childregs = (struct pt_regs *) sp;
>   if (unlikely(p->flags & PF_KTHREAD)) {
>   /* kernel thread */
> - struct thread_info *ti = (void *)task_stack_page(p);
>   memset(childregs, 0, sizeof(struct pt_regs));
>   childregs->gpr[1] = sp + sizeof(struct pt_regs);
>   /* function */
> diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
> index 3807fb05b6de..1b6cabb8e715 100644
> --- a/arch/powerpc/kernel/setup_64.c
> +++ b/arch/powerpc/kernel/setup_64.c
> @@ -69,6 +69,7 @@
>  #include 
>  #include 
>  #include 
> +#include 
>  
>  #ifdef DEBUG
>  #define DBG(fmt...) udbg_printf(fmt)
> @@ -667,16 +668,16 @@ static void __init emergency_stack_init(void)
>   limit = min(safe_stack_limit(), ppc64_rma_size);
>  
>   for_each_possible_cpu(i) {
> - unsigned long sp;
> - sp  = memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit);
> - sp += THREAD_SIZE;
> - paca[i].emergency_sp = __va(sp);
> + struct thread_info *ti;
> + ti = __va(memblock_alloc_base(THREAD_SIZE,

Re: [PATCH 5/6] powerpc/livepatch: Add livepatch stack to struct thread_info

2016-03-28 Thread Balbir Singh 


On 24/03/16 22:04, Michael Ellerman wrote:
> In order to support live patching we need to maintain an alternate
> stack of TOC & LR values. We use the base of the stack for this, and
> store the "live patch stack pointer" in struct thread_info.
>
> Unlike the other fields of thread_info, we can not statically initialise
> that value, so it must be done at run time.
>
> This patch just adds the code to support that, it is not enabled until
> the next patch which actually adds live patch support.
>
> Signed-off-by: Michael Ellerman 
> ---
>  arch/powerpc/include/asm/livepatch.h   |  8 
>  arch/powerpc/include/asm/thread_info.h |  4 +++-
>  arch/powerpc/kernel/irq.c  |  3 +++
>  arch/powerpc/kernel/process.c  |  6 +-
>  arch/powerpc/kernel/setup_64.c | 17 ++---
>  5 files changed, 29 insertions(+), 9 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/livepatch.h 
> b/arch/powerpc/include/asm/livepatch.h
> index ad36e8e34fa1..a402f7f94896 100644
> --- a/arch/powerpc/include/asm/livepatch.h
> +++ b/arch/powerpc/include/asm/livepatch.h
> @@ -49,6 +49,14 @@ static inline unsigned long 
> klp_get_ftrace_location(unsigned long faddr)
>*/
>   return ftrace_location_range(faddr, faddr + 16);
>  }
> +
> +static inline void klp_init_thread_info(struct thread_info *ti)
> +{
> + /* + 1 to account for STACK_END_MAGIC */
> + ti->livepatch_sp = (unsigned long *)(ti + 1) + 1;
> +}
> +#else
> +static void klp_init_thread_info(struct thread_info *ti) { }
>  #endif /* CONFIG_LIVEPATCH */
>  
>  #endif /* _ASM_POWERPC_LIVEPATCH_H */
> diff --git a/arch/powerpc/include/asm/thread_info.h 
> b/arch/powerpc/include/asm/thread_info.h
> index 7efee4a3240b..8febc3f66d53 100644
> --- a/arch/powerpc/include/asm/thread_info.h
> +++ b/arch/powerpc/include/asm/thread_info.h
> @@ -43,7 +43,9 @@ struct thread_info {
>   int preempt_count;  /* 0 => preemptable,
>  <0 => BUG */
>   unsigned long   local_flags;/* private flags for thread */
> -
> +#ifdef CONFIG_LIVEPATCH
> + unsigned long *livepatch_sp;
> +#endif
>   /* low level flags - has atomic operations done on it */
>   unsigned long   flags cacheline_aligned_in_smp;
>  };
> diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
> index 290559df1e8b..3cb46a3b1de7 100644
> --- a/arch/powerpc/kernel/irq.c
> +++ b/arch/powerpc/kernel/irq.c
> @@ -66,6 +66,7 @@
>  #include 
>  #include 
>  #include 
> +#include 
>  
>  #ifdef CONFIG_PPC64
>  #include 
> @@ -607,10 +608,12 @@ void irq_ctx_init(void)
>   memset((void *)softirq_ctx[i], 0, THREAD_SIZE);
>   tp = softirq_ctx[i];
>   tp->cpu = i;
> + klp_init_thread_info(tp);
At this point ti->livepatch_sp points to the next CPUs thread_info for 
softirq_ctx?
>  
>   memset((void *)hardirq_ctx[i], 0, THREAD_SIZE);
>   tp = hardirq_ctx[i];
>   tp->cpu = i;
> + klp_init_thread_info(tp);
Same question here
>   }
>  }
>  
> diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
> index 612df305886b..c27215e6ef48 100644
> --- a/arch/powerpc/kernel/process.c
> +++ b/arch/powerpc/kernel/process.c
> @@ -55,6 +55,8 @@
>  #include 
>  #endif
>  #include 
> +#include 
> +
>  #include 
>  #include 
>  
> @@ -1400,13 +1402,15 @@ int copy_thread(unsigned long clone_flags, unsigned 
> long usp,
>   extern void ret_from_kernel_thread(void);
>   void (*f)(void);
>   unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
> + struct thread_info *ti = task_thread_info(p);
> +
> + klp_init_thread_info(ti);
>  
>   /* Copy registers */
>   sp -= sizeof(struct pt_regs);
>   childregs = (struct pt_regs *) sp;
>   if (unlikely(p->flags & PF_KTHREAD)) {
>   /* kernel thread */
> - struct thread_info *ti = (void *)task_stack_page(p);
>   memset(childregs, 0, sizeof(struct pt_regs));
>   childregs->gpr[1] = sp + sizeof(struct pt_regs);
>   /* function */
> diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
> index 3807fb05b6de..1b6cabb8e715 100644
> --- a/arch/powerpc/kernel/setup_64.c
> +++ b/arch/powerpc/kernel/setup_64.c
> @@ -69,6 +69,7 @@
>  #include 
>  #include 
>  #include 
> +#include 
>  
>  #ifdef DEBUG
>  #define DBG(fmt...) udbg_printf(fmt)
> @@ -667,16 +668,16 @@ static void __init emergency_stack_init(void)
>   limit = min(safe_stack_limit(), ppc64_rma_size);
>  
>   for_each_possible_cpu(i) {
> - unsigned long sp;
> - sp  = memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit);
> - sp += THREAD_SIZE;
> - paca[i].emergency_sp = __va(sp);
> + struct thread_info *ti;
> + ti = __va(memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit));
> +

[PATCH 5/6] powerpc/livepatch: Add livepatch stack to struct thread_info

2016-03-24 Thread Michael Ellerman 
In order to support live patching we need to maintain an alternate
stack of TOC & LR values. We use the base of the stack for this, and
store the "live patch stack pointer" in struct thread_info.

Unlike the other fields of thread_info, we can not statically initialise
that value, so it must be done at run time.

This patch just adds the code to support that, it is not enabled until
the next patch which actually adds live patch support.

Signed-off-by: Michael Ellerman 
---
 arch/powerpc/include/asm/livepatch.h   |  8 
 arch/powerpc/include/asm/thread_info.h |  4 +++-
 arch/powerpc/kernel/irq.c  |  3 +++
 arch/powerpc/kernel/process.c  |  6 +-
 arch/powerpc/kernel/setup_64.c | 17 ++---
 5 files changed, 29 insertions(+), 9 deletions(-)

diff --git a/arch/powerpc/include/asm/livepatch.h 
b/arch/powerpc/include/asm/livepatch.h
index ad36e8e34fa1..a402f7f94896 100644
--- a/arch/powerpc/include/asm/livepatch.h
+++ b/arch/powerpc/include/asm/livepatch.h
@@ -49,6 +49,14 @@ static inline unsigned long klp_get_ftrace_location(unsigned 
long faddr)
 */
return ftrace_location_range(faddr, faddr + 16);
 }
+
+static inline void klp_init_thread_info(struct thread_info *ti)
+{
+   /* + 1 to account for STACK_END_MAGIC */
+   ti->livepatch_sp = (unsigned long *)(ti + 1) + 1;
+}
+#else
+static void klp_init_thread_info(struct thread_info *ti) { }
 #endif /* CONFIG_LIVEPATCH */
 
 #endif /* _ASM_POWERPC_LIVEPATCH_H */
diff --git a/arch/powerpc/include/asm/thread_info.h 
b/arch/powerpc/include/asm/thread_info.h
index 7efee4a3240b..8febc3f66d53 100644
--- a/arch/powerpc/include/asm/thread_info.h
+++ b/arch/powerpc/include/asm/thread_info.h
@@ -43,7 +43,9 @@ struct thread_info {
int preempt_count;  /* 0 => preemptable,
   <0 => BUG */
unsigned long   local_flags;/* private flags for thread */
-
+#ifdef CONFIG_LIVEPATCH
+   unsigned long *livepatch_sp;
+#endif
/* low level flags - has atomic operations done on it */
unsigned long   flags cacheline_aligned_in_smp;
 };
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 290559df1e8b..3cb46a3b1de7 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -66,6 +66,7 @@
 #include 
 #include 
 #include 
+#include 
 
 #ifdef CONFIG_PPC64
 #include 
@@ -607,10 +608,12 @@ void irq_ctx_init(void)
memset((void *)softirq_ctx[i], 0, THREAD_SIZE);
tp = softirq_ctx[i];
tp->cpu = i;
+   klp_init_thread_info(tp);
 
memset((void *)hardirq_ctx[i], 0, THREAD_SIZE);
tp = hardirq_ctx[i];
tp->cpu = i;
+   klp_init_thread_info(tp);
}
 }
 
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 612df305886b..c27215e6ef48 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -55,6 +55,8 @@
 #include 
 #endif
 #include 
+#include 
+
 #include 
 #include 
 
@@ -1400,13 +1402,15 @@ int copy_thread(unsigned long clone_flags, unsigned 
long usp,
extern void ret_from_kernel_thread(void);
void (*f)(void);
unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
+   struct thread_info *ti = task_thread_info(p);
+
+   klp_init_thread_info(ti);
 
/* Copy registers */
sp -= sizeof(struct pt_regs);
childregs = (struct pt_regs *) sp;
if (unlikely(p->flags & PF_KTHREAD)) {
/* kernel thread */
-   struct thread_info *ti = (void *)task_stack_page(p);
memset(childregs, 0, sizeof(struct pt_regs));
childregs->gpr[1] = sp + sizeof(struct pt_regs);
/* function */
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index 3807fb05b6de..1b6cabb8e715 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -69,6 +69,7 @@
 #include 
 #include 
 #include 
+#include 
 
 #ifdef DEBUG
 #define DBG(fmt...) udbg_printf(fmt)
@@ -667,16 +668,16 @@ static void __init emergency_stack_init(void)
limit = min(safe_stack_limit(), ppc64_rma_size);
 
for_each_possible_cpu(i) {
-   unsigned long sp;
-   sp  = memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit);
-   sp += THREAD_SIZE;
-   paca[i].emergency_sp = __va(sp);
+   struct thread_info *ti;
+   ti = __va(memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit));
+   klp_init_thread_info(ti);
+   paca[i].emergency_sp = (void *)ti + THREAD_SIZE;
 
 #ifdef CONFIG_PPC_BOOK3S_64
/* emergency stack for machine check exception handling. */
-   sp  = memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit);
-   sp +=

[PATCH 5/6] powerpc/livepatch: Add livepatch stack to struct thread_info

2016-03-24 Thread Michael Ellerman 
In order to support live patching we need to maintain an alternate
stack of TOC & LR values. We use the base of the stack for this, and
store the "live patch stack pointer" in struct thread_info.

Unlike the other fields of thread_info, we can not statically initialise
that value, so it must be done at run time.

This patch just adds the code to support that, it is not enabled until
the next patch which actually adds live patch support.

Signed-off-by: Michael Ellerman 
---
 arch/powerpc/include/asm/livepatch.h   |  8 
 arch/powerpc/include/asm/thread_info.h |  4 +++-
 arch/powerpc/kernel/irq.c  |  3 +++
 arch/powerpc/kernel/process.c  |  6 +-
 arch/powerpc/kernel/setup_64.c | 17 ++---
 5 files changed, 29 insertions(+), 9 deletions(-)

diff --git a/arch/powerpc/include/asm/livepatch.h 
b/arch/powerpc/include/asm/livepatch.h
index ad36e8e34fa1..a402f7f94896 100644
--- a/arch/powerpc/include/asm/livepatch.h
+++ b/arch/powerpc/include/asm/livepatch.h
@@ -49,6 +49,14 @@ static inline unsigned long klp_get_ftrace_location(unsigned 
long faddr)
 */
return ftrace_location_range(faddr, faddr + 16);
 }
+
+static inline void klp_init_thread_info(struct thread_info *ti)
+{
+   /* + 1 to account for STACK_END_MAGIC */
+   ti->livepatch_sp = (unsigned long *)(ti + 1) + 1;
+}
+#else
+static void klp_init_thread_info(struct thread_info *ti) { }
 #endif /* CONFIG_LIVEPATCH */
 
 #endif /* _ASM_POWERPC_LIVEPATCH_H */
diff --git a/arch/powerpc/include/asm/thread_info.h 
b/arch/powerpc/include/asm/thread_info.h
index 7efee4a3240b..8febc3f66d53 100644
--- a/arch/powerpc/include/asm/thread_info.h
+++ b/arch/powerpc/include/asm/thread_info.h
@@ -43,7 +43,9 @@ struct thread_info {
int preempt_count;  /* 0 => preemptable,
   <0 => BUG */
unsigned long   local_flags;/* private flags for thread */
-
+#ifdef CONFIG_LIVEPATCH
+   unsigned long *livepatch_sp;
+#endif
/* low level flags - has atomic operations done on it */
unsigned long   flags cacheline_aligned_in_smp;
 };
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 290559df1e8b..3cb46a3b1de7 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -66,6 +66,7 @@
 #include 
 #include 
 #include 
+#include 
 
 #ifdef CONFIG_PPC64
 #include 
@@ -607,10 +608,12 @@ void irq_ctx_init(void)
memset((void *)softirq_ctx[i], 0, THREAD_SIZE);
tp = softirq_ctx[i];
tp->cpu = i;
+   klp_init_thread_info(tp);
 
memset((void *)hardirq_ctx[i], 0, THREAD_SIZE);
tp = hardirq_ctx[i];
tp->cpu = i;
+   klp_init_thread_info(tp);
}
 }
 
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 612df305886b..c27215e6ef48 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -55,6 +55,8 @@
 #include 
 #endif
 #include 
+#include 
+
 #include 
 #include 
 
@@ -1400,13 +1402,15 @@ int copy_thread(unsigned long clone_flags, unsigned 
long usp,
extern void ret_from_kernel_thread(void);
void (*f)(void);
unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
+   struct thread_info *ti = task_thread_info(p);
+
+   klp_init_thread_info(ti);
 
/* Copy registers */
sp -= sizeof(struct pt_regs);
childregs = (struct pt_regs *) sp;
if (unlikely(p->flags & PF_KTHREAD)) {
/* kernel thread */
-   struct thread_info *ti = (void *)task_stack_page(p);
memset(childregs, 0, sizeof(struct pt_regs));
childregs->gpr[1] = sp + sizeof(struct pt_regs);
/* function */
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index 3807fb05b6de..1b6cabb8e715 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -69,6 +69,7 @@
 #include 
 #include 
 #include 
+#include 
 
 #ifdef DEBUG
 #define DBG(fmt...) udbg_printf(fmt)
@@ -667,16 +668,16 @@ static void __init emergency_stack_init(void)
limit = min(safe_stack_limit(), ppc64_rma_size);
 
for_each_possible_cpu(i) {
-   unsigned long sp;
-   sp  = memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit);
-   sp += THREAD_SIZE;
-   paca[i].emergency_sp = __va(sp);
+   struct thread_info *ti;
+   ti = __va(memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit));
+   klp_init_thread_info(ti);
+   paca[i].emergency_sp = (void *)ti + THREAD_SIZE;
 
 #ifdef CONFIG_PPC_BOOK3S_64
/* emergency stack for machine check exception handling. */
-   sp  = memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit);
-   sp += THREAD_SIZE;
-