[PATCH v4 10/16] powerpc/watchpoint: Use loop for thread_struct->ptrace_bps
From: Ravi Bangoria <hidden>
Date: 2020-04-30 04:35:42
Also in:
lkml
Subsystem:
linux for powerpc (32-bit and 64-bit), ptrace support, the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Oleg Nesterov, Linus Torvalds
ptrace_bps is already an array of size HBP_NUM_MAX. But we use hardcoded index 0 while fetching/updating it. Convert such code to loop over array. ptrace interface to use multiple watchpoint remains same. eg: two PPC_PTRACE_SETHWDEBUG calls will create two watchpoint if hw underneath supports it. Signed-off-by: Ravi Bangoria <redacted> Reviewed-by: Michael Neuling <redacted> --- arch/powerpc/kernel/hw_breakpoint.c | 7 ++++-- arch/powerpc/kernel/process.c | 6 ++++- arch/powerpc/kernel/ptrace/ptrace-noadv.c | 28 +++++++++++++++++------ 3 files changed, 31 insertions(+), 10 deletions(-)
diff --git a/arch/powerpc/kernel/hw_breakpoint.c b/arch/powerpc/kernel/hw_breakpoint.c
index 5826f1f2cab9..772b2c953220 100644
--- a/arch/powerpc/kernel/hw_breakpoint.c
+++ b/arch/powerpc/kernel/hw_breakpoint.c@@ -419,10 +419,13 @@ NOKPROBE_SYMBOL(hw_breakpoint_exceptions_notify); */ void flush_ptrace_hw_breakpoint(struct task_struct *tsk) { + int i; struct thread_struct *t = &tsk->thread; - unregister_hw_breakpoint(t->ptrace_bps[0]); - t->ptrace_bps[0] = NULL; + for (i = 0; i < nr_wp_slots(); i++) { + unregister_hw_breakpoint(t->ptrace_bps[i]); + t->ptrace_bps[i] = NULL; + } } void hw_breakpoint_pmu_read(struct perf_event *bp)
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 6d1b7cede900..41a59a37383b 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c@@ -1604,6 +1604,9 @@ int copy_thread_tls(unsigned long clone_flags, unsigned long usp, void (*f)(void); unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE; struct thread_info *ti = task_thread_info(p); +#ifdef CONFIG_HAVE_HW_BREAKPOINT + int i; +#endif klp_init_thread_info(p);
@@ -1663,7 +1666,8 @@ int copy_thread_tls(unsigned long clone_flags, unsigned long usp, p->thread.ksp_limit = (unsigned long)end_of_stack(p); #endif #ifdef CONFIG_HAVE_HW_BREAKPOINT - p->thread.ptrace_bps[0] = NULL; + for (i = 0; i < nr_wp_slots(); i++) + p->thread.ptrace_bps[i] = NULL; #endif p->thread.fp_save_area = NULL;
diff --git a/arch/powerpc/kernel/ptrace/ptrace-noadv.c b/arch/powerpc/kernel/ptrace/ptrace-noadv.c
index 0dbb35392dd2..08cb8c1b504c 100644
--- a/arch/powerpc/kernel/ptrace/ptrace-noadv.c
+++ b/arch/powerpc/kernel/ptrace/ptrace-noadv.c@@ -168,6 +168,19 @@ int ptrace_set_debugreg(struct task_struct *task, unsigned long addr, unsigned l return 0; } +#ifdef CONFIG_HAVE_HW_BREAKPOINT +static int find_empty_ptrace_bp(struct thread_struct *thread) +{ + int i; + + for (i = 0; i < nr_wp_slots(); i++) { + if (!thread->ptrace_bps[i]) + return i; + } + return -1; +} +#endif + static int find_empty_hw_brk(struct thread_struct *thread) { int i;
@@ -217,8 +230,9 @@ long ppc_set_hwdebug(struct task_struct *child, struct ppc_hw_breakpoint *bp_inf len = 1; else return -EINVAL; - bp = thread->ptrace_bps[0]; - if (bp) + + i = find_empty_ptrace_bp(thread); + if (i < 0) return -ENOSPC; /* Create a new breakpoint request if one doesn't exist already */
@@ -228,13 +242,13 @@ long ppc_set_hwdebug(struct task_struct *child, struct ppc_hw_breakpoint *bp_inf arch_bp_generic_fields(brk.type, &attr.bp_type); bp = register_user_hw_breakpoint(&attr, ptrace_triggered, NULL, child); - thread->ptrace_bps[0] = bp; + thread->ptrace_bps[i] = bp; if (IS_ERR(bp)) { - thread->ptrace_bps[0] = NULL; + thread->ptrace_bps[i] = NULL; return PTR_ERR(bp); } - return 1; + return i + 1; #endif /* CONFIG_HAVE_HW_BREAKPOINT */ if (bp_info->addr_mode != PPC_BREAKPOINT_MODE_EXACT)
@@ -263,10 +277,10 @@ long ppc_del_hwdebug(struct task_struct *child, long data) return -EINVAL; #ifdef CONFIG_HAVE_HW_BREAKPOINT - bp = thread->ptrace_bps[0]; + bp = thread->ptrace_bps[data - 1]; if (bp) { unregister_hw_breakpoint(bp); - thread->ptrace_bps[0] = NULL; + thread->ptrace_bps[data - 1] = NULL; } else { ret = -ENOENT; }
--
2.21.1