v4.19.13 snapshot.
diff --git a/arch/sh/kernel/hw_breakpoint.c b/arch/sh/kernel/hw_breakpoint.c
new file mode 100644
index 0000000..d9ff3b4
--- /dev/null
+++ b/arch/sh/kernel/hw_breakpoint.c
@@ -0,0 +1,410 @@
+/*
+ * arch/sh/kernel/hw_breakpoint.c
+ *
+ * Unified kernel/user-space hardware breakpoint facility for the on-chip UBC.
+ *
+ * Copyright (C) 2009 - 2010 Paul Mundt
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+#include <linux/init.h>
+#include <linux/perf_event.h>
+#include <linux/sched/signal.h>
+#include <linux/hw_breakpoint.h>
+#include <linux/percpu.h>
+#include <linux/kallsyms.h>
+#include <linux/notifier.h>
+#include <linux/kprobes.h>
+#include <linux/kdebug.h>
+#include <linux/io.h>
+#include <linux/clk.h>
+#include <asm/hw_breakpoint.h>
+#include <asm/mmu_context.h>
+#include <asm/ptrace.h>
+#include <asm/traps.h>
+
+/*
+ * Stores the breakpoints currently in use on each breakpoint address
+ * register for each cpus
+ */
+static DEFINE_PER_CPU(struct perf_event *, bp_per_reg[HBP_NUM]);
+
+/*
+ * A dummy placeholder for early accesses until the CPUs get a chance to
+ * register their UBCs later in the boot process.
+ */
+static struct sh_ubc ubc_dummy = { .num_events = 0 };
+
+static struct sh_ubc *sh_ubc __read_mostly = &ubc_dummy;
+
+/*
+ * Install a perf counter breakpoint.
+ *
+ * We seek a free UBC channel and use it for this breakpoint.
+ *
+ * Atomic: we hold the counter->ctx->lock and we only handle variables
+ * and registers local to this cpu.
+ */
+int arch_install_hw_breakpoint(struct perf_event *bp)
+{
+ struct arch_hw_breakpoint *info = counter_arch_bp(bp);
+ int i;
+
+ for (i = 0; i < sh_ubc->num_events; i++) {
+ struct perf_event **slot = this_cpu_ptr(&bp_per_reg[i]);
+
+ if (!*slot) {
+ *slot = bp;
+ break;
+ }
+ }
+
+ if (WARN_ONCE(i == sh_ubc->num_events, "Can't find any breakpoint slot"))
+ return -EBUSY;
+
+ clk_enable(sh_ubc->clk);
+ sh_ubc->enable(info, i);
+
+ return 0;
+}
+
+/*
+ * Uninstall the breakpoint contained in the given counter.
+ *
+ * First we search the debug address register it uses and then we disable
+ * it.
+ *
+ * Atomic: we hold the counter->ctx->lock and we only handle variables
+ * and registers local to this cpu.
+ */
+void arch_uninstall_hw_breakpoint(struct perf_event *bp)
+{
+ struct arch_hw_breakpoint *info = counter_arch_bp(bp);
+ int i;
+
+ for (i = 0; i < sh_ubc->num_events; i++) {
+ struct perf_event **slot = this_cpu_ptr(&bp_per_reg[i]);
+
+ if (*slot == bp) {
+ *slot = NULL;
+ break;
+ }
+ }
+
+ if (WARN_ONCE(i == sh_ubc->num_events, "Can't find any breakpoint slot"))
+ return;
+
+ sh_ubc->disable(info, i);
+ clk_disable(sh_ubc->clk);
+}
+
+static int get_hbp_len(u16 hbp_len)
+{
+ unsigned int len_in_bytes = 0;
+
+ switch (hbp_len) {
+ case SH_BREAKPOINT_LEN_1:
+ len_in_bytes = 1;
+ break;
+ case SH_BREAKPOINT_LEN_2:
+ len_in_bytes = 2;
+ break;
+ case SH_BREAKPOINT_LEN_4:
+ len_in_bytes = 4;
+ break;
+ case SH_BREAKPOINT_LEN_8:
+ len_in_bytes = 8;
+ break;
+ }
+ return len_in_bytes;
+}
+
+/*
+ * Check for virtual address in kernel space.
+ */
+int arch_check_bp_in_kernelspace(struct arch_hw_breakpoint *hw)
+{
+ unsigned int len;
+ unsigned long va;
+
+ va = hw->address;
+ len = get_hbp_len(hw->len);
+
+ return (va >= TASK_SIZE) && ((va + len - 1) >= TASK_SIZE);
+}
+
+int arch_bp_generic_fields(int sh_len, int sh_type,
+ int *gen_len, int *gen_type)
+{
+ /* Len */
+ switch (sh_len) {
+ case SH_BREAKPOINT_LEN_1:
+ *gen_len = HW_BREAKPOINT_LEN_1;
+ break;
+ case SH_BREAKPOINT_LEN_2:
+ *gen_len = HW_BREAKPOINT_LEN_2;
+ break;
+ case SH_BREAKPOINT_LEN_4:
+ *gen_len = HW_BREAKPOINT_LEN_4;
+ break;
+ case SH_BREAKPOINT_LEN_8:
+ *gen_len = HW_BREAKPOINT_LEN_8;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ /* Type */
+ switch (sh_type) {
+ case SH_BREAKPOINT_READ:
+ *gen_type = HW_BREAKPOINT_R;
+ case SH_BREAKPOINT_WRITE:
+ *gen_type = HW_BREAKPOINT_W;
+ break;
+ case SH_BREAKPOINT_RW:
+ *gen_type = HW_BREAKPOINT_W | HW_BREAKPOINT_R;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int arch_build_bp_info(struct perf_event *bp,
+ const struct perf_event_attr *attr,
+ struct arch_hw_breakpoint *hw)
+{
+ hw->address = attr->bp_addr;
+
+ /* Len */
+ switch (attr->bp_len) {
+ case HW_BREAKPOINT_LEN_1:
+ hw->len = SH_BREAKPOINT_LEN_1;
+ break;
+ case HW_BREAKPOINT_LEN_2:
+ hw->len = SH_BREAKPOINT_LEN_2;
+ break;
+ case HW_BREAKPOINT_LEN_4:
+ hw->len = SH_BREAKPOINT_LEN_4;
+ break;
+ case HW_BREAKPOINT_LEN_8:
+ hw->len = SH_BREAKPOINT_LEN_8;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ /* Type */
+ switch (attr->bp_type) {
+ case HW_BREAKPOINT_R:
+ hw->type = SH_BREAKPOINT_READ;
+ break;
+ case HW_BREAKPOINT_W:
+ hw->type = SH_BREAKPOINT_WRITE;
+ break;
+ case HW_BREAKPOINT_W | HW_BREAKPOINT_R:
+ hw->type = SH_BREAKPOINT_RW;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+/*
+ * Validate the arch-specific HW Breakpoint register settings
+ */
+int hw_breakpoint_arch_parse(struct perf_event *bp,
+ const struct perf_event_attr *attr,
+ struct arch_hw_breakpoint *hw)
+{
+ unsigned int align;
+ int ret;
+
+ ret = arch_build_bp_info(bp, attr, hw);
+ if (ret)
+ return ret;
+
+ ret = -EINVAL;
+
+ switch (hw->len) {
+ case SH_BREAKPOINT_LEN_1:
+ align = 0;
+ break;
+ case SH_BREAKPOINT_LEN_2:
+ align = 1;
+ break;
+ case SH_BREAKPOINT_LEN_4:
+ align = 3;
+ break;
+ case SH_BREAKPOINT_LEN_8:
+ align = 7;
+ break;
+ default:
+ return ret;
+ }
+
+ /*
+ * Check that the low-order bits of the address are appropriate
+ * for the alignment implied by len.
+ */
+ if (hw->address & align)
+ return -EINVAL;
+
+ return 0;
+}
+
+/*
+ * Release the user breakpoints used by ptrace
+ */
+void flush_ptrace_hw_breakpoint(struct task_struct *tsk)
+{
+ int i;
+ struct thread_struct *t = &tsk->thread;
+
+ for (i = 0; i < sh_ubc->num_events; i++) {
+ unregister_hw_breakpoint(t->ptrace_bps[i]);
+ t->ptrace_bps[i] = NULL;
+ }
+}
+
+static int __kprobes hw_breakpoint_handler(struct die_args *args)
+{
+ int cpu, i, rc = NOTIFY_STOP;
+ struct perf_event *bp;
+ unsigned int cmf, resume_mask;
+
+ /*
+ * Do an early return if none of the channels triggered.
+ */
+ cmf = sh_ubc->triggered_mask();
+ if (unlikely(!cmf))
+ return NOTIFY_DONE;
+
+ /*
+ * By default, resume all of the active channels.
+ */
+ resume_mask = sh_ubc->active_mask();
+
+ /*
+ * Disable breakpoints during exception handling.
+ */
+ sh_ubc->disable_all();
+
+ cpu = get_cpu();
+ for (i = 0; i < sh_ubc->num_events; i++) {
+ unsigned long event_mask = (1 << i);
+
+ if (likely(!(cmf & event_mask)))
+ continue;
+
+ /*
+ * The counter may be concurrently released but that can only
+ * occur from a call_rcu() path. We can then safely fetch
+ * the breakpoint, use its callback, touch its counter
+ * while we are in an rcu_read_lock() path.
+ */
+ rcu_read_lock();
+
+ bp = per_cpu(bp_per_reg[i], cpu);
+ if (bp)
+ rc = NOTIFY_DONE;
+
+ /*
+ * Reset the condition match flag to denote completion of
+ * exception handling.
+ */
+ sh_ubc->clear_triggered_mask(event_mask);
+
+ /*
+ * bp can be NULL due to concurrent perf counter
+ * removing.
+ */
+ if (!bp) {
+ rcu_read_unlock();
+ break;
+ }
+
+ /*
+ * Don't restore the channel if the breakpoint is from
+ * ptrace, as it always operates in one-shot mode.
+ */
+ if (bp->overflow_handler == ptrace_triggered)
+ resume_mask &= ~(1 << i);
+
+ perf_bp_event(bp, args->regs);
+
+ /* Deliver the signal to userspace */
+ if (!arch_check_bp_in_kernelspace(&bp->hw.info)) {
+ force_sig_fault(SIGTRAP, TRAP_HWBKPT,
+ (void __user *)NULL, current);
+ }
+
+ rcu_read_unlock();
+ }
+
+ if (cmf == 0)
+ rc = NOTIFY_DONE;
+
+ sh_ubc->enable_all(resume_mask);
+
+ put_cpu();
+
+ return rc;
+}
+
+BUILD_TRAP_HANDLER(breakpoint)
+{
+ unsigned long ex = lookup_exception_vector();
+ TRAP_HANDLER_DECL;
+
+ notify_die(DIE_BREAKPOINT, "breakpoint", regs, 0, ex, SIGTRAP);
+}
+
+/*
+ * Handle debug exception notifications.
+ */
+int __kprobes hw_breakpoint_exceptions_notify(struct notifier_block *unused,
+ unsigned long val, void *data)
+{
+ struct die_args *args = data;
+
+ if (val != DIE_BREAKPOINT)
+ return NOTIFY_DONE;
+
+ /*
+ * If the breakpoint hasn't been triggered by the UBC, it's
+ * probably from a debugger, so don't do anything more here.
+ *
+ * This also permits the UBC interface clock to remain off for
+ * non-UBC breakpoints, as we don't need to check the triggered
+ * or active channel masks.
+ */
+ if (args->trapnr != sh_ubc->trap_nr)
+ return NOTIFY_DONE;
+
+ return hw_breakpoint_handler(data);
+}
+
+void hw_breakpoint_pmu_read(struct perf_event *bp)
+{
+ /* TODO */
+}
+
+int register_sh_ubc(struct sh_ubc *ubc)
+{
+ /* Bail if it's already assigned */
+ if (sh_ubc != &ubc_dummy)
+ return -EBUSY;
+ sh_ubc = ubc;
+
+ pr_info("HW Breakpoints: %s UBC support registered\n", ubc->name);
+
+ WARN_ON(ubc->num_events > HBP_NUM);
+
+ return 0;
+}