From 303e6a9ddcdc168e92253c78cdb4bbe1e10d78b3 Mon Sep 17 00:00:00 2001 From: Ravi Bangoria Date: Thu, 14 May 2020 16:47:34 +0530 Subject: [PATCH] powerpc/watchpoint: Convert thread_struct->hw_brk to an array So far powerpc hw supported only one watchpoint. But Power10 is introducing 2nd DAWR. Convert thread_struct->hw_brk into an array. Signed-off-by: Ravi Bangoria Signed-off-by: Michael Ellerman Reviewed-by: Michael Neuling Link: https://lore.kernel.org/r/20200514111741.97993-10-ravi.bangoria@linux.ibm.com --- arch/powerpc/include/asm/processor.h | 2 +- arch/powerpc/kernel/process.c | 60 ++++++++++++++--------- arch/powerpc/kernel/ptrace/ptrace-noadv.c | 40 ++++++++++----- arch/powerpc/kernel/ptrace/ptrace32.c | 4 +- arch/powerpc/kernel/signal.c | 13 +++-- 5 files changed, 78 insertions(+), 41 deletions(-) diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h index f209c5703ee2..fba6b586e3c8 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 f303aea61794..d94d8925711c 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -711,21 +711,49 @@ 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(int i, struct arch_hw_breakpoint *brk) { preempt_disable(); - __set_breakpoint(0, brk); + __set_breakpoint(i, brk); 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; + struct arch_hw_breakpoint null_brk = {0}; + + for (i = 0; i < nr_wp_slots(); i++) { + thread->hw_brk[i] = null_brk; + if (ppc_breakpoint_available()) + set_breakpoint(i, &thread->hw_brk[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 (likely(hw_brk_match(this_cpu_ptr(¤t_brk[i]), + &new->thread.hw_brk[i]))) + continue; + + __set_breakpoint(i, &new->thread.hw_brk[i]); + } } #endif /* !CONFIG_HAVE_HW_BREAKPOINT */ #endif /* CONFIG_PPC_ADV_DEBUG_REGS */ @@ -829,19 +857,6 @@ 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) @@ -1174,8 +1189,7 @@ 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(0, &new->thread.hw_brk); + 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 8e29138a344a..b4143b6ff093 100644 --- a/arch/powerpc/kernel/signal.c +++ b/arch/powerpc/kernel/signal.c @@ -265,15 +265,20 @@ static void do_signal(struct task_struct *tsk) return; /* no signals delivered */ } -#ifndef CONFIG_PPC_ADV_DEBUG_REGS /* * Reenable the DABR before delivering the signal to * 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(0, &tsk->thread.hw_brk); -#endif + if (!IS_ENABLED(CONFIG_PPC_ADV_DEBUG_REGS)) { + int i; + + for (i = 0; i < nr_wp_slots(); i++) { + if (tsk->thread.hw_brk[i].address && tsk->thread.hw_brk[i].type) + __set_breakpoint(i, &tsk->thread.hw_brk[i]); + } + } + /* Re-enable the breakpoints for the signal stack */ thread_change_pc(tsk, tsk->thread.regs);