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-rw-r--r--arch/riscv/kernel/probes/uprobes.c188
1 files changed, 188 insertions, 0 deletions
diff --git a/arch/riscv/kernel/probes/uprobes.c b/arch/riscv/kernel/probes/uprobes.c
new file mode 100644
index 0000000000..4b3dc8beaf
--- /dev/null
+++ b/arch/riscv/kernel/probes/uprobes.c
@@ -0,0 +1,188 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/highmem.h>
+#include <linux/ptrace.h>
+#include <linux/uprobes.h>
+#include <asm/insn.h>
+
+#include "decode-insn.h"
+
+#define UPROBE_TRAP_NR UINT_MAX
+
+bool is_swbp_insn(uprobe_opcode_t *insn)
+{
+#ifdef CONFIG_RISCV_ISA_C
+ return (*insn & 0xffff) == UPROBE_SWBP_INSN;
+#else
+ return *insn == UPROBE_SWBP_INSN;
+#endif
+}
+
+bool is_trap_insn(uprobe_opcode_t *insn)
+{
+ return riscv_insn_is_ebreak(*insn) || riscv_insn_is_c_ebreak(*insn);
+}
+
+unsigned long uprobe_get_swbp_addr(struct pt_regs *regs)
+{
+ return instruction_pointer(regs);
+}
+
+int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm,
+ unsigned long addr)
+{
+ probe_opcode_t opcode;
+
+ opcode = *(probe_opcode_t *)(&auprobe->insn[0]);
+
+ auprobe->insn_size = GET_INSN_LENGTH(opcode);
+
+ switch (riscv_probe_decode_insn(&opcode, &auprobe->api)) {
+ case INSN_REJECTED:
+ return -EINVAL;
+
+ case INSN_GOOD_NO_SLOT:
+ auprobe->simulate = true;
+ break;
+
+ case INSN_GOOD:
+ auprobe->simulate = false;
+ break;
+
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+int arch_uprobe_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
+{
+ struct uprobe_task *utask = current->utask;
+
+ utask->autask.saved_cause = current->thread.bad_cause;
+ current->thread.bad_cause = UPROBE_TRAP_NR;
+
+ instruction_pointer_set(regs, utask->xol_vaddr);
+
+ return 0;
+}
+
+int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
+{
+ struct uprobe_task *utask = current->utask;
+
+ WARN_ON_ONCE(current->thread.bad_cause != UPROBE_TRAP_NR);
+ current->thread.bad_cause = utask->autask.saved_cause;
+
+ instruction_pointer_set(regs, utask->vaddr + auprobe->insn_size);
+
+ return 0;
+}
+
+bool arch_uprobe_xol_was_trapped(struct task_struct *t)
+{
+ if (t->thread.bad_cause != UPROBE_TRAP_NR)
+ return true;
+
+ return false;
+}
+
+bool arch_uprobe_skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs)
+{
+ probe_opcode_t insn;
+ unsigned long addr;
+
+ if (!auprobe->simulate)
+ return false;
+
+ insn = *(probe_opcode_t *)(&auprobe->insn[0]);
+ addr = instruction_pointer(regs);
+
+ if (auprobe->api.handler)
+ auprobe->api.handler(insn, addr, regs);
+
+ return true;
+}
+
+void arch_uprobe_abort_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
+{
+ struct uprobe_task *utask = current->utask;
+
+ current->thread.bad_cause = utask->autask.saved_cause;
+ /*
+ * Task has received a fatal signal, so reset back to probbed
+ * address.
+ */
+ instruction_pointer_set(regs, utask->vaddr);
+}
+
+bool arch_uretprobe_is_alive(struct return_instance *ret, enum rp_check ctx,
+ struct pt_regs *regs)
+{
+ if (ctx == RP_CHECK_CHAIN_CALL)
+ return regs->sp <= ret->stack;
+ else
+ return regs->sp < ret->stack;
+}
+
+unsigned long
+arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr,
+ struct pt_regs *regs)
+{
+ unsigned long ra;
+
+ ra = regs->ra;
+
+ regs->ra = trampoline_vaddr;
+
+ return ra;
+}
+
+int arch_uprobe_exception_notify(struct notifier_block *self,
+ unsigned long val, void *data)
+{
+ return NOTIFY_DONE;
+}
+
+bool uprobe_breakpoint_handler(struct pt_regs *regs)
+{
+ if (uprobe_pre_sstep_notifier(regs))
+ return true;
+
+ return false;
+}
+
+bool uprobe_single_step_handler(struct pt_regs *regs)
+{
+ if (uprobe_post_sstep_notifier(regs))
+ return true;
+
+ return false;
+}
+
+void arch_uprobe_copy_ixol(struct page *page, unsigned long vaddr,
+ void *src, unsigned long len)
+{
+ /* Initialize the slot */
+ void *kaddr = kmap_atomic(page);
+ void *dst = kaddr + (vaddr & ~PAGE_MASK);
+
+ memcpy(dst, src, len);
+
+ /* Add ebreak behind opcode to simulate singlestep */
+ if (vaddr) {
+ dst += GET_INSN_LENGTH(*(probe_opcode_t *)src);
+ *(uprobe_opcode_t *)dst = __BUG_INSN_32;
+ }
+
+ kunmap_atomic(kaddr);
+
+ /*
+ * We probably need flush_icache_user_page() but it needs vma.
+ * This should work on most of architectures by default. If
+ * architecture needs to do something different it can define
+ * its own version of the function.
+ */
+ flush_dcache_page(page);
+}