[PATCH v6 09/16] powerpc/watchpoint: Convert thread_struct->hw_brk to an array
Ravi Bangoria
ravi.bangoria at linux.ibm.com
Thu May 14 21:17:34 AEST 2020
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 <ravi.bangoria at linux.ibm.com>
Reviewed-by: Michael Neuling <mikey at neuling.org>
---
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);
--
2.26.2
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