Re: [PATCH 09/15] powerpc/watchpoint: Convert thread_struct->hw_brk to an array
From: Christophe Leroy
Date: Tue Mar 17 2020 - 06:37:55 EST
Le 09/03/2020 Ã 09:58, Ravi Bangoria a ÃcritÂ:
So far powerpc hw supported only one watchpoint. But Future Power
architecture is introducing 2nd DAWR. Convert thread_struct->hw_brk
into an array.
Looks like you are doing a lot more than that in this patch.
Should this patch be splitted in two parts ?
Christophe
Signed-off-by: Ravi Bangoria <ravi.bangoria@xxxxxxxxxxxxx>
---
arch/powerpc/include/asm/processor.h | 2 +-
arch/powerpc/kernel/process.c | 43 ++++++++++++++++++++--------
arch/powerpc/kernel/ptrace.c | 42 ++++++++++++++++++++-------
arch/powerpc/kernel/ptrace32.c | 4 +--
arch/powerpc/kernel/signal.c | 9 ++++--
5 files changed, 72 insertions(+), 28 deletions(-)
diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h
index 666b2825278c..57a8fac2e72b 100644
--- a/arch/powerpc/include/asm/processor.h
+++ b/arch/powerpc/include/asm/processor.h
@@ -183,7 +183,7 @@ 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 f6bb2586fa5d..42ff62ef749c 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -704,21 +704,25 @@ 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++) {
+ 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);
+ }
}
#endif /* !CONFIG_HAVE_HW_BREAKPOINT */
#endif /* CONFIG_PPC_ADV_DEBUG_REGS */
@@ -1141,6 +1145,24 @@ static inline void restore_sprs(struct thread_struct *old_thread,
thread_pkey_regs_restore(new_thread, old_thread);
}
+#ifndef CONFIG_HAVE_HW_BREAKPOINT
+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);
+ }
+ }
+}
+#else
+static void switch_hw_breakpoint(struct task_struct *new)
+{
+}
+#endif
+
struct task_struct *__switch_to(struct task_struct *prev,
struct task_struct *new)
{
@@ -1172,10 +1194,7 @@ struct task_struct *__switch_to(struct task_struct *prev,
* For PPC_BOOK3S_64, we use the hw-breakpoint interfaces that would
* 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);
-#endif /* CONFIG_HAVE_HW_BREAKPOINT */
+ switch_hw_breakpoint(new);
#endif
/*
diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
index dd46e174dbe7..f6d7955fc61e 100644
--- a/arch/powerpc/kernel/ptrace.c
+++ b/arch/powerpc/kernel/ptrace.c
@@ -2382,6 +2382,11 @@ void ptrace_triggered(struct perf_event *bp,
}
#endif /* CONFIG_HAVE_HW_BREAKPOINT */
+/*
+ * 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.
+ */
static int ptrace_set_debugreg(struct task_struct *task, unsigned long addr,
unsigned long data)
{
@@ -2451,7 +2456,7 @@ static int ptrace_set_debugreg(struct task_struct *task, unsigned long addr,
return ret;
}
thread->ptrace_bps[0] = bp;
- thread->hw_brk = hw_brk;
+ thread->hw_brk[0] = hw_brk;
return 0;
}
@@ -2473,7 +2478,7 @@ static int ptrace_set_debugreg(struct task_struct *task, unsigned long addr,
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;
#else /* CONFIG_PPC_ADV_DEBUG_REGS */
/* As described above, it was assumed 3 bits were passed with the data
* address, but we will assume only the mode bits will be passed
@@ -2824,9 +2829,23 @@ static int set_dac_range(struct task_struct *child,
}
#endif /* CONFIG_PPC_ADV_DEBUG_DAC_RANGE */
+#ifndef CONFIG_PPC_ADV_DEBUG_REGS
+static int 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;
+}
+#endif
+
static 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);
@@ -2919,15 +2938,16 @@ static long ppc_set_hwdebug(struct task_struct *child,
if (bp_info->addr_mode != PPC_BREAKPOINT_MODE_EXACT)
return -EINVAL;
- if (child->thread.hw_brk.address)
+ i = 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;
#endif /* !CONFIG_PPC_ADV_DEBUG_DVCS */
}
@@ -2955,7 +2975,7 @@ static long ppc_del_hwdebug(struct task_struct *child, long data)
}
return rc;
#else
- if (data != 1)
+ if (data < 1 || data > nr_wp_slots())
return -EINVAL;
#ifdef CONFIG_HAVE_HW_BREAKPOINT
@@ -2967,11 +2987,11 @@ static long ppc_del_hwdebug(struct task_struct *child, long data)
ret = -ENOENT;
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;
@@ -3124,8 +3144,8 @@ long arch_ptrace(struct task_struct *child, long request,
#ifdef CONFIG_PPC_ADV_DEBUG_REGS
ret = put_user(child->thread.debug.dac1, datalp);
#else
- 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));
ret = put_user(dabr_fake, datalp);
#endif
break;
diff --git a/arch/powerpc/kernel/ptrace32.c b/arch/powerpc/kernel/ptrace32.c
index f37eb53de1a1..e227cd320b46 100644
--- a/arch/powerpc/kernel/ptrace32.c
+++ b/arch/powerpc/kernel/ptrace32.c
@@ -270,8 +270,8 @@ 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 8bc6cc55420a..3116896e89a6 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);
+ }
#endif
/* Re-enable the breakpoints for the signal stack */
thread_change_pc(tsk, tsk->thread.regs);