Implement kprobes support for PA-RISC.
Signed-off-by: Sven Schnelle <svens@xxxxxxxxxxxxxx>
---
arch/parisc/Kconfig | 1 +
arch/parisc/include/asm/kprobes.h | 55 +++++++++
arch/parisc/kernel/Makefile | 1 +
arch/parisc/kernel/kprobes.c | 183 ++++++++++++++++++++++++++++++
arch/parisc/kernel/traps.c | 14 +++
5 files changed, 254 insertions(+)
create mode 100644 arch/parisc/include/asm/kprobes.h
create mode 100644 arch/parisc/kernel/kprobes.c
diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig
index a80c19c7fc0e..7712688608f4 100644
--- a/arch/parisc/Kconfig
+++ b/arch/parisc/Kconfig
@@ -55,6 +55,7 @@ config PARISC
select NEED_DMA_MAP_STATE
select NEED_SG_DMA_LENGTH
select HAVE_ARCH_KGDB
+ select HAVE_KPROBES
help
The PA-RISC microprocessor is designed by Hewlett-Packard and used
diff --git a/arch/parisc/include/asm/kprobes.h b/arch/parisc/include/asm/kprobes.h
new file mode 100644
index 000000000000..e09cf2deeafe
--- /dev/null
+++ b/arch/parisc/include/asm/kprobes.h
@@ -0,0 +1,55 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * arch/parisc/include/asm/kprobes.h
+ *
+ * PA-RISC kprobes implementation
+ *
+ * Copyright (c) 2019 Sven Schnelle <svens@xxxxxxxxxxxxxx>
+ */
+
+#ifndef _PARISC_KPROBES_H
+#define _PARISC_KPROBES_H
+
+#ifdef CONFIG_KPROBES
+
+#include <asm-generic/kprobes.h>
+#include <linux/types.h>
+#include <linux/ptrace.h>
+#include <linux/notifier.h>
+
+#define PARISC_KPROBES_BREAK_INSN 0x3ff801f
+#define __ARCH_WANT_KPROBES_INSN_SLOT
+#define MAX_INSN_SIZE 1
+
+typedef u32 kprobe_opcode_t;
+struct kprobe;
+
+void arch_remove_kprobe(struct kprobe *p);
+
+#define flush_insn_slot(p) \
+ flush_icache_range((unsigned long)&(p)->ainsn.insn[0], \
+ (unsigned long)&(p)->ainsn.insn[0] + \
+ sizeof(kprobe_opcode_t))
+
+#define kretprobe_blacklist_size 0
+
+struct arch_specific_insn {
+ kprobe_opcode_t *insn;
+};
+
+struct prev_kprobe {
+ struct kprobe *kp;
+ unsigned long status;
+};
+
+struct kprobe_ctlblk {
+ unsigned int kprobe_status;
+ struct prev_kprobe prev_kprobe;
+ unsigned long iaoq[2];
+};
+
+int __kprobes parisc_kprobe_break_handler(struct pt_regs *regs);
+int __kprobes parisc_kprobe_ss_handler(struct pt_regs *regs);
+
+#endif /* CONFIG_KPROBES */
+#endif /* _PARISC_KPROBES_H */
diff --git a/arch/parisc/kernel/Makefile b/arch/parisc/kernel/Makefile
index 5012da96c196..b818b28c8a99 100644
--- a/arch/parisc/kernel/Makefile
+++ b/arch/parisc/kernel/Makefile
@@ -34,3 +34,4 @@ obj-$(CONFIG_PARISC_CPU_TOPOLOGY) += topology.o
obj-$(CONFIG_FUNCTION_TRACER) += ftrace.o
obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += ftrace.o
obj-$(CONFIG_KGDB) += kgdb.o
+obj-$(CONFIG_KPROBES) += kprobes.o
diff --git a/arch/parisc/kernel/kprobes.c b/arch/parisc/kernel/kprobes.c
new file mode 100644
index 000000000000..8b1977cd3eb9
--- /dev/null
+++ b/arch/parisc/kernel/kprobes.c
@@ -0,0 +1,183 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * arch/parisc/kernel/kprobes.c
+ *
+ * PA-RISC kprobes implementation
+ *
+ * Copyright (c) 2019 Sven Schnelle <svens@xxxxxxxxxxxxxx>
+ */
+
+#include <linux/types.h>
+#include <linux/kprobes.h>
+#include <linux/slab.h>
+#include <asm/cacheflush.h>
+#include <asm/patch.h>
+
+DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
+DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
+
+int __kprobes arch_prepare_kprobe(struct kprobe *p)
+{
+ if ((unsigned long)p->addr & 3UL)
+ return -EINVAL;
+
+ p->ainsn.insn = get_insn_slot();
+ if (!p->ainsn.insn)
+ return -ENOMEM;
+
+ memcpy(p->ainsn.insn, p->addr,
+ MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
+ p->opcode = *p->addr;
+ flush_insn_slot(p);
+ return 0;
+}
+
+void __kprobes arch_remove_kprobe(struct kprobe *p)
+{
+ if (!p->ainsn.insn)
+ return;
+
+ free_insn_slot(p->ainsn.insn, 0);
+ p->ainsn.insn = NULL;
+}
+
+void __kprobes arch_arm_kprobe(struct kprobe *p)
+{
+ patch_text(p->addr, PARISC_KPROBES_BREAK_INSN);
+}
+
+void __kprobes arch_disarm_kprobe(struct kprobe *p)
+{
+ patch_text(p->addr, p->opcode);
+}
+
+static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
+{
+ kcb->prev_kprobe.kp = kprobe_running();
+ kcb->prev_kprobe.status = kcb->kprobe_status;
+}
+
+static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
+{
+ __this_cpu_write(current_kprobe, kcb->prev_kprobe.kp);
+ kcb->kprobe_status = kcb->prev_kprobe.status;
+}
+
+static inline void __kprobes set_current_kprobe(struct kprobe *p)
+{
+ __this_cpu_write(current_kprobe, p);
+}
+
+static void __kprobes setup_singlestep(struct kprobe *p,
+ struct kprobe_ctlblk *kcb, struct pt_regs *regs)
+{
+ kcb->iaoq[0] = regs->iaoq[0];
+ kcb->iaoq[1] = regs->iaoq[1];
+ regs->iaoq[0] = (unsigned long)p->ainsn.insn;
+ mtctl(0, 0);
+ regs->gr[0] |= PSW_R;
+}
+
+int __kprobes parisc_kprobe_break_handler(struct pt_regs *regs)
+{
+ struct kprobe *p;
+ struct kprobe_ctlblk *kcb;
+
+ preempt_disable();
+
+ kcb = get_kprobe_ctlblk();
+ p = get_kprobe((unsigned long *)regs->iaoq[0]);
+
+ if (!p) {
+ preempt_enable_no_resched();
+ return 0;
+ }
+
+ if (kprobe_running()) {
+ /*
+ * We have reentered the kprobe_handler, since another kprobe
+ * was hit while within the handler, we save the original
+ * kprobes and single step on the instruction of the new probe
+ * without calling any user handlers to avoid recursive
+ * kprobes.
+ */
+ save_previous_kprobe(kcb);
+ set_current_kprobe(p);
+ kprobes_inc_nmissed_count(p);
+ setup_singlestep(p, kcb, regs);
+ kcb->kprobe_status = KPROBE_REENTER;
+ return 1;
+ }
+
+ set_current_kprobe(p);
+ kcb->kprobe_status = KPROBE_HIT_ACTIVE;
+
+ /* If we have no pre-handler or it returned 0, we continue with
+ * normal processing. If we have a pre-handler and it returned
+ * non-zero - which means user handler setup registers to exit
+ * to another instruction, we must skip the single stepping.
+ */
+
+ if (!p->pre_handler || !p->pre_handler(p, regs)) {
+ setup_singlestep(p, kcb, regs);
+ kcb->kprobe_status = KPROBE_HIT_SS;
+ } else {
+ reset_current_kprobe();
+ preempt_enable_no_resched();
+ }
+ return 1;
+}
+
+int __kprobes parisc_kprobe_ss_handler(struct pt_regs *regs)
+{
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+ struct kprobe *p = kprobe_running();
+
+ if (regs->iaoq[0] != (unsigned long)p->ainsn.insn+4)
+ return 0;
+
+ /* restore back original saved kprobe variables and continue */
+ if (kcb->kprobe_status == KPROBE_REENTER) {
+ restore_previous_kprobe(kcb);
+ return 1;
+ }
+
+ /* for absolute branch instructions we can copy iaoq_b. for relative
+ * branch instructions we need to calculate the new address based on the
+ * difference between iaoq_f and iaoq_b. We cannot use iaoq_b without
+ * modificationt because it's based on our ainsn.insn address.
+ */
+
+ if (p->post_handler)
+ p->post_handler(p, regs, 0);
+
+ switch (regs->iir >> 26) {
+ case 0x38: /* BE */
+ case 0x39: /* BE,L */
+ case 0x3a: /* BV */
+ case 0x3b: /* BVE */
+ /* for absolute branches, regs->iaoq[1] has already the right
+ * address
+ */
+ regs->iaoq[0] = kcb->iaoq[1];
+ break;
+ default:
+ regs->iaoq[1] = kcb->iaoq[0];
+ regs->iaoq[1] += (regs->iaoq[1] - regs->iaoq[0]) + 4;
+ regs->iaoq[0] = kcb->iaoq[1];
+ break;
+ }
+ kcb->kprobe_status = KPROBE_HIT_SSDONE;
+ reset_current_kprobe();
+ return 1;
+}
+
+bool arch_kprobe_on_func_entry(unsigned long offset)
+{
+ return !offset;
+}
+
+int __init arch_init_kprobes(void)
+{
+ return 0;
+}
diff --git a/arch/parisc/kernel/traps.c b/arch/parisc/kernel/traps.c
index 4a0516524f2a..096e319adeb3 100644
--- a/arch/parisc/kernel/traps.c
+++ b/arch/parisc/kernel/traps.c
@@ -43,6 +43,7 @@
#include <asm/tlbflush.h>
#include <asm/cacheflush.h>
#include <linux/kgdb.h>
+#include <linux/kprobes.h>
#include "../math-emu/math-emu.h" /* for handle_fpe() */
@@ -294,6 +295,14 @@ static void handle_break(struct pt_regs *regs)
(tt == BUG_TRAP_TYPE_NONE) ? 9 : 0);
}
+#ifdef CONFIG_KPROBES
+ if (unlikely(iir == PARISC_KPROBES_BREAK_INSN)) {
+ parisc_kprobe_break_handler(regs);
+ return;
+ }
+
+#endif
+
#ifdef CONFIG_KGDB
if (unlikely(iir == PARISC_KGDB_COMPILED_BREAK_INSN ||
iir == PARISC_KGDB_BREAK_INSN)) {
@@ -528,6 +537,11 @@ void notrace handle_interruption(int code, struct pt_regs *regs)
/* Recovery counter trap */
regs->gr[0] &= ~PSW_R;
+#ifdef CONFIG_KPROBES
+ if (parisc_kprobe_ss_handler(regs))
+ return;
+#endif
+
#ifdef CONFIG_KGDB
if (kgdb_single_step) {
kgdb_handle_exception(0, SIGTRAP, 0, regs);
--
2.20.1
