Messages in this thread Patch in this message | | | Subject | Re: [PATCH v2 09/16] powerpc/watchpoint: Convert thread_struct->hw_brk to an array | From | Christophe Leroy <> | Date | Wed, 1 Apr 2020 08:43:57 +0200 |
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Le 01/04/2020 à 08:13, Ravi Bangoria a écrit : > So far powerpc hw supported only one watchpoint. But Future Power > architecture is introducing 2nd DAWR. Convert thread_struct->hw_brk > into an array. > > Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com> > --- > arch/powerpc/include/asm/processor.h | 2 +- > arch/powerpc/kernel/process.c | 61 ++++++++++++++--------- > arch/powerpc/kernel/ptrace/ptrace-noadv.c | 40 +++++++++++---- > arch/powerpc/kernel/ptrace/ptrace32.c | 4 +- > arch/powerpc/kernel/signal.c | 9 +++- > 5 files changed, 77 insertions(+), 39 deletions(-) > > diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h > index 90f6dbc7ff00..65b03162cd67 100644 > --- a/arch/powerpc/include/asm/processor.h > +++ b/arch/powerpc/include/asm/processor.h > @@ -187,7 +187,7 @@ struct thread_struct { > */ > struct perf_event *last_hit_ubp; > #endif /* CONFIG_HAVE_HW_BREAKPOINT */ > - struct arch_hw_breakpoint hw_brk; /* info on the hardware breakpoint */ > + struct arch_hw_breakpoint hw_brk[HBP_NUM_MAX]; /* hardware breakpoint info */ > unsigned long trap_nr; /* last trap # on this thread */ > u8 load_slb; /* Ages out SLB preload cache entries */ > u8 load_fp; > diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c > index e0275fcd0c55..f5b4f21e822b 100644 > --- a/arch/powerpc/kernel/process.c > +++ b/arch/powerpc/kernel/process.c > @@ -704,21 +704,50 @@ void switch_booke_debug_regs(struct debug_reg *new_debug) > EXPORT_SYMBOL_GPL(switch_booke_debug_regs); > #else /* !CONFIG_PPC_ADV_DEBUG_REGS */ > #ifndef CONFIG_HAVE_HW_BREAKPOINT > -static void set_breakpoint(struct arch_hw_breakpoint *brk) > +static void set_breakpoint(struct arch_hw_breakpoint *brk, int i) > { > preempt_disable(); > - __set_breakpoint(brk, 0); > + __set_breakpoint(brk, i); > preempt_enable(); > } > > static void set_debug_reg_defaults(struct thread_struct *thread) > { > - thread->hw_brk.address = 0; > - thread->hw_brk.type = 0; > - thread->hw_brk.len = 0; > - thread->hw_brk.hw_len = 0; > - if (ppc_breakpoint_available()) > - set_breakpoint(&thread->hw_brk); > + int i; > + > + for (i = 0; i < nr_wp_slots(); i++) {
Maybe you could add the following that you added other places:
struct arch_hw_breakpoint null_brk = {0};
Then do
thread->hw_brk[i] = null_brk;
> + thread->hw_brk[i].address = 0; > + thread->hw_brk[i].type = 0; > + thread->hw_brk[i].len = 0; > + thread->hw_brk[i].hw_len = 0; > + if (ppc_breakpoint_available()) > + set_breakpoint(&thread->hw_brk[i], i); > + } > +} > + > +static inline bool hw_brk_match(struct arch_hw_breakpoint *a, > + struct arch_hw_breakpoint *b) > +{ > + if (a->address != b->address) > + return false; > + if (a->type != b->type) > + return false; > + if (a->len != b->len) > + return false; > + /* no need to check hw_len. it's calculated from address and len */ > + return true; > +} > + > +static void switch_hw_breakpoint(struct task_struct *new) > +{ > + int i; > + > + for (i = 0; i < nr_wp_slots(); i++) { > + if (unlikely(!hw_brk_match(this_cpu_ptr(¤t_brk[i]), > + &new->thread.hw_brk[i]))) { > + __set_breakpoint(&new->thread.hw_brk[i], i); > + }
Or could be:
if (likely(hw_brk_match(this_cpu_ptr(¤t_brk[i]), &new->thread.hw_brk[i]))) continue; __set_breakpoint(&new->thread.hw_brk[i], i);
> + } > } > #endif /* !CONFIG_HAVE_HW_BREAKPOINT */ > #endif /* CONFIG_PPC_ADV_DEBUG_REGS */ > @@ -822,19 +851,6 @@ bool ppc_breakpoint_available(void) > } > EXPORT_SYMBOL_GPL(ppc_breakpoint_available); > > -static inline bool hw_brk_match(struct arch_hw_breakpoint *a, > - struct arch_hw_breakpoint *b) > -{ > - if (a->address != b->address) > - return false; > - if (a->type != b->type) > - return false; > - if (a->len != b->len) > - return false; > - /* no need to check hw_len. it's calculated from address and len */ > - return true; > -} > - > #ifdef CONFIG_PPC_TRANSACTIONAL_MEM > > static inline bool tm_enabled(struct task_struct *tsk) > @@ -1167,8 +1183,7 @@ struct task_struct *__switch_to(struct task_struct *prev, > * schedule DABR > */ > #ifndef CONFIG_HAVE_HW_BREAKPOINT > - if (unlikely(!hw_brk_match(this_cpu_ptr(¤t_brk[0]), &new->thread.hw_brk))) > - __set_breakpoint(&new->thread.hw_brk, 0); > + switch_hw_breakpoint(new); > #endif /* CONFIG_HAVE_HW_BREAKPOINT */ > #endif > > diff --git a/arch/powerpc/kernel/ptrace/ptrace-noadv.c b/arch/powerpc/kernel/ptrace/ptrace-noadv.c > index 12962302d6a4..0dbb35392dd2 100644 > --- a/arch/powerpc/kernel/ptrace/ptrace-noadv.c > +++ b/arch/powerpc/kernel/ptrace/ptrace-noadv.c > @@ -67,11 +67,16 @@ int ptrace_get_debugreg(struct task_struct *child, unsigned long addr, > /* We only support one DABR and no IABRS at the moment */ > if (addr > 0) > return -EINVAL; > - dabr_fake = ((child->thread.hw_brk.address & (~HW_BRK_TYPE_DABR)) | > - (child->thread.hw_brk.type & HW_BRK_TYPE_DABR)); > + dabr_fake = ((child->thread.hw_brk[0].address & (~HW_BRK_TYPE_DABR)) | > + (child->thread.hw_brk[0].type & HW_BRK_TYPE_DABR)); > return put_user(dabr_fake, datalp); > } > > +/* > + * ptrace_set_debugreg() fakes DABR and DABR is only one. So even if > + * internal hw supports more than one watchpoint, we support only one > + * watchpoint with this interface. > + */ > int ptrace_set_debugreg(struct task_struct *task, unsigned long addr, unsigned long data) > { > #ifdef CONFIG_HAVE_HW_BREAKPOINT > @@ -137,7 +142,7 @@ int ptrace_set_debugreg(struct task_struct *task, unsigned long addr, unsigned l > return ret; > > thread->ptrace_bps[0] = bp; > - thread->hw_brk = hw_brk; > + thread->hw_brk[0] = hw_brk; > return 0; > } > > @@ -159,12 +164,24 @@ int ptrace_set_debugreg(struct task_struct *task, unsigned long addr, unsigned l > if (set_bp && (!ppc_breakpoint_available())) > return -ENODEV; > #endif /* CONFIG_HAVE_HW_BREAKPOINT */ > - task->thread.hw_brk = hw_brk; > + task->thread.hw_brk[0] = hw_brk; > return 0; > } > > +static int find_empty_hw_brk(struct thread_struct *thread) > +{ > + int i; > + > + for (i = 0; i < nr_wp_slots(); i++) { > + if (!thread->hw_brk[i].address) > + return i; > + } > + return -1; > +} > + > long ppc_set_hwdebug(struct task_struct *child, struct ppc_hw_breakpoint *bp_info) > { > + int i; > #ifdef CONFIG_HAVE_HW_BREAKPOINT > int len = 0; > struct thread_struct *thread = &child->thread; > @@ -223,15 +240,16 @@ long ppc_set_hwdebug(struct task_struct *child, struct ppc_hw_breakpoint *bp_inf > if (bp_info->addr_mode != PPC_BREAKPOINT_MODE_EXACT) > return -EINVAL; > > - if (child->thread.hw_brk.address) > + i = find_empty_hw_brk(&child->thread); > + if (i < 0) > return -ENOSPC; > > if (!ppc_breakpoint_available()) > return -ENODEV; > > - child->thread.hw_brk = brk; > + child->thread.hw_brk[i] = brk; > > - return 1; > + return i + 1; > } > > long ppc_del_hwdebug(struct task_struct *child, long data) > @@ -241,7 +259,7 @@ long ppc_del_hwdebug(struct task_struct *child, long data) > struct thread_struct *thread = &child->thread; > struct perf_event *bp; > #endif /* CONFIG_HAVE_HW_BREAKPOINT */ > - if (data != 1) > + if (data < 1 || data > nr_wp_slots()) > return -EINVAL; > > #ifdef CONFIG_HAVE_HW_BREAKPOINT > @@ -254,11 +272,11 @@ long ppc_del_hwdebug(struct task_struct *child, long data) > } > return ret; > #else /* CONFIG_HAVE_HW_BREAKPOINT */ > - if (child->thread.hw_brk.address == 0) > + if (child->thread.hw_brk[data - 1].address == 0) > return -ENOENT; > > - child->thread.hw_brk.address = 0; > - child->thread.hw_brk.type = 0; > + child->thread.hw_brk[data - 1].address = 0; > + child->thread.hw_brk[data - 1].type = 0; > #endif /* CONFIG_HAVE_HW_BREAKPOINT */ > > return 0; > diff --git a/arch/powerpc/kernel/ptrace/ptrace32.c b/arch/powerpc/kernel/ptrace/ptrace32.c > index 7976ddf29c0e..7589a9665ffb 100644 > --- a/arch/powerpc/kernel/ptrace/ptrace32.c > +++ b/arch/powerpc/kernel/ptrace/ptrace32.c > @@ -259,8 +259,8 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request, > ret = put_user(child->thread.debug.dac1, (u32 __user *)data); > #else > dabr_fake = ( > - (child->thread.hw_brk.address & (~HW_BRK_TYPE_DABR)) | > - (child->thread.hw_brk.type & HW_BRK_TYPE_DABR)); > + (child->thread.hw_brk[0].address & (~HW_BRK_TYPE_DABR)) | > + (child->thread.hw_brk[0].type & HW_BRK_TYPE_DABR)); > ret = put_user(dabr_fake, (u32 __user *)data); > #endif > break; > diff --git a/arch/powerpc/kernel/signal.c b/arch/powerpc/kernel/signal.c > index bbf237f072d4..b559b114d03d 100644 > --- a/arch/powerpc/kernel/signal.c > +++ b/arch/powerpc/kernel/signal.c > @@ -107,6 +107,9 @@ static void do_signal(struct task_struct *tsk) > struct ksignal ksig = { .sig = 0 }; > int ret; > int is32 = is_32bit_task(); > +#ifndef CONFIG_PPC_ADV_DEBUG_REGS > + int i; > +#endif > > BUG_ON(tsk != current); > > @@ -128,8 +131,10 @@ static void do_signal(struct task_struct *tsk) > * user space. The DABR will have been cleared if it > * triggered inside the kernel. > */ > - if (tsk->thread.hw_brk.address && tsk->thread.hw_brk.type) > - __set_breakpoint(&tsk->thread.hw_brk, 0); > + for (i = 0; i < nr_wp_slots(); i++) { > + if (tsk->thread.hw_brk[i].address && tsk->thread.hw_brk[i].type) > + __set_breakpoint(&tsk->thread.hw_brk[i], i); > + }
thread.hwbrk also exists when CONFIG_PPC_ADV_DEBUG_REGS is selected.
You could replace the #ifndef CONFIG_PPC_ADV_DEBUG_REGS by an if (!IS_ENABLED(CONFIG_PPC_ADV_DEBUG_REGS)) and then no need of an ifdef when declaring the int i;
> #endif > /* Re-enable the breakpoints for the signal stack */ > thread_change_pc(tsk, tsk->thread.regs); >
Christophe
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