1 files changed, 147 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/crash_dump.c b/arch/powerpc/kernel/crash_dump.c
new file mode 100644
index 000000000..735e89337
--- /dev/null
+++ b/arch/powerpc/kernel/crash_dump.c
@@ -0,0 +1,147 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Routines for doing kexec-based kdump.
+ *
+ * Copyright (C) 2005, IBM Corp.
+ *
+ * Created by: Michael Ellerman
+ */
+
+#undef DEBUG
+
+#include <linux/crash_dump.h>
+#include <linux/io.h>
+#include <linux/memblock.h>
+#include <asm/code-patching.h>
+#include <asm/kdump.h>
+#include <asm/prom.h>
+#include <asm/firmware.h>
+#include <linux/uaccess.h>
+#include <asm/rtas.h>
+#include <asm/inst.h>
+
+#ifdef DEBUG
+#include <asm/udbg.h>
+#define DBG(fmt...) udbg_printf(fmt)
+#else
+#define DBG(fmt...)
+#endif
+
+#ifndef CONFIG_NONSTATIC_KERNEL
+void __init reserve_kdump_trampoline(void)
+{
+	memblock_reserve(0, KDUMP_RESERVE_LIMIT);
+}
+
+static void __init create_trampoline(unsigned long addr)
+{
+	struct ppc_inst *p = (struct ppc_inst *)addr;
+
+	/* The maximum range of a single instruction branch, is the current
+	 * instruction's address + (32 MB - 4) bytes. For the trampoline we
+	 * need to branch to current address + 32 MB. So we insert a nop at
+	 * the trampoline address, then the next instruction (+ 4 bytes)
+	 * does a branch to (32 MB - 4). The net effect is that when we
+	 * branch to "addr" we jump to ("addr" + 32 MB). Although it requires
+	 * two instructions it doesn't require any registers.
+	 */
+	patch_instruction(p, ppc_inst(PPC_INST_NOP));
+	patch_branch((void *)p + 4, addr + PHYSICAL_START, 0);
+}
+
+void __init setup_kdump_trampoline(void)
+{
+	unsigned long i;
+
+	DBG(" -> setup_kdump_trampoline()\n");
+
+	for (i = KDUMP_TRAMPOLINE_START; i < KDUMP_TRAMPOLINE_END; i += 8) {
+		create_trampoline(i);
+	}
+
+#ifdef CONFIG_PPC_PSERIES
+	create_trampoline(__pa(system_reset_fwnmi) - PHYSICAL_START);
+	create_trampoline(__pa(machine_check_fwnmi) - PHYSICAL_START);
+#endif /* CONFIG_PPC_PSERIES */
+
+	DBG(" <- setup_kdump_trampoline()\n");
+}
+#endif /* CONFIG_NONSTATIC_KERNEL */
+
+static size_t copy_oldmem_vaddr(void *vaddr, char *buf, size_t csize,
+                               unsigned long offset, int userbuf)
+{
+	if (userbuf) {
+		if (copy_to_user((char __user *)buf, (vaddr + offset), csize))
+			return -EFAULT;
+	} else
+		memcpy(buf, (vaddr + offset), csize);
+
+	return csize;
+}
+
+/**
+ * copy_oldmem_page - copy one page from "oldmem"
+ * @pfn: page frame number to be copied
+ * @buf: target memory address for the copy; this can be in kernel address
+ *      space or user address space (see @userbuf)
+ * @csize: number of bytes to copy
+ * @offset: offset in bytes into the page (based on pfn) to begin the copy
+ * @userbuf: if set, @buf is in user address space, use copy_to_user(),
+ *      otherwise @buf is in kernel address space, use memcpy().
+ *
+ * Copy a page from "oldmem". For this page, there is no pte mapped
+ * in the current kernel. We stitch up a pte, similar to kmap_atomic.
+ */
+ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
+			size_t csize, unsigned long offset, int userbuf)
+{
+	void  *vaddr;
+	phys_addr_t paddr;
+
+	if (!csize)
+		return 0;
+
+	csize = min_t(size_t, csize, PAGE_SIZE);
+	paddr = pfn << PAGE_SHIFT;
+
+	if (memblock_is_region_memory(paddr, csize)) {
+		vaddr = __va(paddr);
+		csize = copy_oldmem_vaddr(vaddr, buf, csize, offset, userbuf);
+	} else {
+		vaddr = ioremap_cache(paddr, PAGE_SIZE);
+		csize = copy_oldmem_vaddr(vaddr, buf, csize, offset, userbuf);
+		iounmap(vaddr);
+	}
+
+	return csize;
+}
+
+#ifdef CONFIG_PPC_RTAS
+/*
+ * The crashkernel region will almost always overlap the RTAS region, so
+ * we have to be careful when shrinking the crashkernel region.
+ */
+void crash_free_reserved_phys_range(unsigned long begin, unsigned long end)
+{
+	unsigned long addr;
+	const __be32 *basep, *sizep;
+	unsigned int rtas_start = 0, rtas_end = 0;
+
+	basep = of_get_property(rtas.dev, "linux,rtas-base", NULL);
+	sizep = of_get_property(rtas.dev, "rtas-size", NULL);
+
+	if (basep && sizep) {
+		rtas_start = be32_to_cpup(basep);
+		rtas_end = rtas_start + be32_to_cpup(sizep);
+	}
+
+	for (addr = begin; addr < end; addr += PAGE_SIZE) {
+		/* Does this page overlap with the RTAS region? */
+		if (addr <= rtas_end && ((addr + PAGE_SIZE) > rtas_start))
+			continue;
+
+		free_reserved_page(pfn_to_page(addr >> PAGE_SHIFT));
+	}
+}
+#endif