Merge tag 'loongarch-5.20' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson

Pull LoongArch updates from Huacai Chen:

 - Optimise getcpu() with vDSO

 - PCI enablement on top of pci & irqchip changes

 - Stack unwinder and stack trace support

 - Some bug fixes and build error fixes

 - Update the default config file

* tag 'loongarch-5.20' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson:
  docs/zh_CN/LoongArch: Add I14 description
  docs/LoongArch: Add I14 description
  LoongArch: Update Loongson-3 default config file
  LoongArch: Add USER_STACKTRACE support
  LoongArch: Add STACKTRACE support
  LoongArch: Add prologue unwinder support
  LoongArch: Add guess unwinder support
  LoongArch: Add vDSO syscall __vdso_getcpu()
  LoongArch: Add PCI controller support
  LoongArch: Parse MADT to get multi-processor information
  LoongArch: Jump to the link address before enable PG
  LoongArch: Requires __force attributes for any casts
  LoongArch: Fix unsigned comparison with less than zero
  LoongArch: Adjust arch/loongarch/Kconfig
  LoongArch: cpuinfo: Fix a warning for CONFIG_CPUMASK_OFFSTACK

1 files changed, 78 insertions, 0 deletions

diff --git a/arch/loongarch/kernel/stacktrace.c b/arch/loongarch/kernel/stacktrace.c
new file mode 100644
index 000000000000..3a690f96f00c
--- /dev/null
+++ b/arch/loongarch/kernel/stacktrace.c
@@ -0,0 +1,78 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Stack trace management functions
+ *
+ * Copyright (C) 2022 Loongson Technology Corporation Limited
+ */
+#include <linux/sched.h>
+#include <linux/stacktrace.h>
+#include <linux/uaccess.h>
+
+#include <asm/stacktrace.h>
+#include <asm/unwind.h>
+
+void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
+		     struct task_struct *task, struct pt_regs *regs)
+{
+	unsigned long addr;
+	struct pt_regs dummyregs;
+	struct unwind_state state;
+
+	regs = &dummyregs;
+
+	if (task == current) {
+		regs->regs[3] = (unsigned long)__builtin_frame_address(0);
+		regs->csr_era = (unsigned long)__builtin_return_address(0);
+	} else {
+		regs->regs[3] = thread_saved_fp(task);
+		regs->csr_era = thread_saved_ra(task);
+	}
+
+	regs->regs[1] = 0;
+	for (unwind_start(&state, task, regs);
+	      !unwind_done(&state); unwind_next_frame(&state)) {
+		addr = unwind_get_return_address(&state);
+		if (!addr || !consume_entry(cookie, addr))
+			break;
+	}
+}
+
+static int
+copy_stack_frame(unsigned long fp, struct stack_frame *frame)
+{
+	int ret = 1;
+	unsigned long err;
+	unsigned long __user *user_frame_tail;
+
+	user_frame_tail = (unsigned long *)(fp - sizeof(struct stack_frame));
+	if (!access_ok(user_frame_tail, sizeof(*frame)))
+		return 0;
+
+	pagefault_disable();
+	err = (__copy_from_user_inatomic(frame, user_frame_tail, sizeof(*frame)));
+	if (err || (unsigned long)user_frame_tail >= frame->fp)
+		ret = 0;
+	pagefault_enable();
+
+	return ret;
+}
+
+void arch_stack_walk_user(stack_trace_consume_fn consume_entry, void *cookie,
+			  const struct pt_regs *regs)
+{
+	unsigned long fp = regs->regs[22];
+
+	while (fp && !((unsigned long)fp & 0xf)) {
+		struct stack_frame frame;
+
+		frame.fp = 0;
+		frame.ra = 0;
+		if (!copy_stack_frame(fp, &frame))
+			break;
+		if (!frame.ra)
+			break;
+		if (!consume_entry(cookie, frame.ra))
+			break;
+		fp = frame.fp;
+	}
+}