Add a pseudo-driver to "kexec" an OpenBSD/powerpc64 kernel. Heavily

based on the octboot driver that we use for octeon.  To be used in the
bootloader kernel.

6 files changed, 283 insertions, 4 deletions

diff --git a/sys/arch/powerpc64/conf/files.powerpc64 b/sys/arch/powerpc64/conf/files.powerpc64
index f3c4518717d..68af464f2e1 100644
--- a/sys/arch/powerpc64/conf/files.powerpc64
+++ b/sys/arch/powerpc64/conf/files.powerpc64
@@ -1,4 +1,4 @@
-# $OpenBSD: files.powerpc64,v 1.21 2020/07/14 20:39:40 kettenis Exp $
+# $OpenBSD: files.powerpc64,v 1.22 2020/07/16 19:37:58 kettenis Exp $
 
 maxpartitions	16
 maxusers	2 8 128
@@ -38,6 +38,10 @@ file	arch/powerpc64/dev/pci_machdep.c
 file	netinet/in_cksum.c
 file	netinet/in4_cksum.c
 
+pseudo-device	kexec
+file	arch/powerpc64/dev/kexec.c		kexec needs-flag
+file	arch/powerpc64/dev/kexec_subr.S		kexec needs-flag
+
 pseudo-device	openprom
 file	arch/powerpc64/powerpc64/openprom.c	openprom needs-flag
 
diff --git a/sys/arch/powerpc64/dev/kexec.c b/sys/arch/powerpc64/dev/kexec.c
new file mode 100644
index 00000000000..01c881603a7
--- /dev/null
+++ b/sys/arch/powerpc64/dev/kexec.c
@@ -0,0 +1,195 @@
+/*	$OpenBSD: kexec.c,v 1.1 2020/07/16 19:37:58 kettenis Exp $	*/
+
+/*
+ * Copyright (c) 2019-2020 Visa Hankala
+ * Copyright (c) 2020 Mark Kettenis <kettenis@openbsd.org>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/exec_elf.h>
+#include <sys/malloc.h>
+#include <sys/proc.h>
+
+#include <uvm/uvm_extern.h>
+
+#include <machine/kexec.h>
+#include <machine/opal.h>
+
+int	kexec_kexec(struct kexec_args *, struct proc *);
+int	kexec_read(struct kexec_args *, void *, size_t, off_t);
+void	kexec(paddr_t, paddr_t);
+
+void
+kexecattach(int num)
+{
+}
+
+int
+kexecopen(dev_t dev, int flags, int mode, struct proc *p)
+{
+	return (0);
+}
+
+int
+kexecclose(dev_t dev, int flags, int mode, struct proc *p)
+{
+	return (0);
+}
+
+int
+kexecioctl(dev_t dev, u_long cmd, caddr_t data, int flags, struct proc *p)
+{
+	int error = 0;
+
+	switch (cmd) {
+	case KIOC_KEXEC:
+		error = suser(p);
+		if (error != 0)
+			break;
+		error = kexec_kexec((struct kexec_args *)data, p);
+		break;
+
+	case KIOC_GETBOOTDUID:
+		memcpy(data, bootduid, sizeof(bootduid));
+		break;
+
+	default:
+		error = ENOTTY;
+		break;
+	}
+
+	return error;
+}
+
+int
+kexec_kexec(struct kexec_args *kargs, struct proc *p)
+{
+	extern paddr_t fdt_pa;
+	struct kmem_pa_mode kp_kexec = {
+		.kp_constraint = &no_constraint,
+		.kp_boundary = SEGMENT_SIZE,
+		.kp_maxseg = 1,
+		.kp_zero = 1
+	};
+	Elf_Ehdr eh;
+	Elf_Phdr *ph = NULL;
+	Elf_Shdr *sh = NULL;
+	vaddr_t start = VM_MAX_ADDRESS;
+	vaddr_t end = 0;
+	paddr_t start_pa;
+	vsize_t align = 0;;
+	caddr_t addr;
+	size_t phsize, shsize, size;
+	int error, i;
+
+	/*
+	 * Read the headers and validate them.
+	 */
+	error = kexec_read(kargs, &eh, sizeof(eh), 0);
+	if (error != 0)
+		goto fail;
+
+	/* Load program headers. */
+	ph = mallocarray(eh.e_phnum, sizeof(Elf_Phdr), M_TEMP, M_NOWAIT);
+	if (ph == NULL) {
+		error = ENOMEM;
+		goto fail;
+	}
+	phsize = eh.e_phnum * sizeof(Elf_Phdr);
+	error = kexec_read(kargs, ph, phsize, eh.e_phoff);
+	if (error != 0)
+		goto fail;
+
+	/* Load section headers. */
+	sh = mallocarray(eh.e_shnum, sizeof(Elf_Shdr), M_TEMP, M_NOWAIT);
+	if (sh == NULL) {
+		error = ENOMEM;
+		goto fail;
+	}
+	shsize = eh.e_shnum * sizeof(Elf_Shdr);
+	error = kexec_read(kargs, sh, shsize, eh.e_shoff);
+	if (error != 0)
+		goto fail;
+
+	/*
+	 * Allocate physical memory and load the segments.
+	 */
+
+	for (i = 0; i < eh.e_phnum; i++) {
+		if (ph[i].p_type != PT_LOAD)
+			continue;
+		start = MIN(start, ph[i].p_vaddr);
+		align = MAX(align, ph[i].p_align);
+		end = MAX(end, ph[i].p_vaddr + ph[i].p_memsz);
+	}
+	size = round_page(end) - start;
+
+	kp_kexec.kp_align = align;
+	addr = km_alloc(size, &kv_any, &kp_kexec, &kd_nowait);
+	if (addr == NULL) {
+		error = ENOMEM;
+		goto fail;
+	}
+
+	for (i = 0; i < eh.e_phnum; i++) {
+		if (ph[i].p_type != PT_LOAD)
+			continue;
+
+		error = kexec_read(kargs, addr + (ph[i].p_vaddr - start),
+		    ph[i].p_filesz, ph[i].p_offset);
+		if (error != 0)
+			goto fail;
+
+		/* Clear any BSS. */
+		if (ph[i].p_memsz > ph[i].p_filesz) {
+			memset(addr + (ph[i].p_vaddr + ph[i].p_filesz) - start,
+			    0, ph[i].p_memsz - ph[i].p_filesz);
+		}
+	}
+
+	for (i = 0; i < eh.e_phnum; i++) {
+		if (ph[i].p_type != PT_OPENBSD_RANDOMIZE)
+			continue;
+
+		/* Assume that the segment is inside a LOAD segment. */
+		arc4random_buf(addr + ph[i].p_vaddr - start, ph[i].p_filesz);
+	}
+
+	printf("launching kernel\n");
+
+	config_suspend_all(DVACT_POWERDOWN);
+
+	intr_disable();
+
+	pmap_extract(pmap_kernel(), (vaddr_t)addr, &start_pa);
+	kexec(start_pa + (eh.e_entry - start), fdt_pa);
+
+	for (;;)
+		continue;
+
+fail:
+	free(sh, M_TEMP, shsize);
+	free(ph, M_TEMP, phsize);
+	return error;
+}
+
+int
+kexec_read(struct kexec_args *kargs, void *buf, size_t size, off_t off)
+{
+	if (off + size < off || off + size > kargs->klen)
+		return ENOEXEC;
+	return copyin(kargs->kimg + off, buf, size);
+}
diff --git a/sys/arch/powerpc64/dev/kexec_subr.S b/sys/arch/powerpc64/dev/kexec_subr.S
new file mode 100644
index 00000000000..2f604996da8
--- /dev/null
+++ b/sys/arch/powerpc64/dev/kexec_subr.S
@@ -0,0 +1,35 @@
+/*	$OpenBSD: kexec_subr.S,v 1.1 2020/07/16 19:37:58 kettenis Exp $	*/
+
+/*
+ * Copyright (c) 2020 Mark Kettenis <kettenis@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include "assym.h"
+
+#include <machine/psl.h>
+
+	.abiversion 2
+
+	.text
+
+	.globl kexec
+kexec:
+	mtctr	%r3
+	mr	%r3, %r4
+	mfmsr	%r31
+	andi.	%r31, %r31, ~(PSL_DR|PSL_IR|PSL_ME|PSL_RI)@l
+	mtmsr	%r31
+	isync
+	bctr
diff --git a/sys/arch/powerpc64/include/conf.h b/sys/arch/powerpc64/include/conf.h
index 62f960b0155..28f660fe733 100644
--- a/sys/arch/powerpc64/include/conf.h
+++ b/sys/arch/powerpc64/include/conf.h
@@ -7,10 +7,18 @@ cdev_decl(mm);
 cdev_decl(opalcons);
 
 /* open, close, ioctl */
+#define cdev_kexec_init(c,n) { \
+	dev_init(c,n,open), dev_init(c,n,close), (dev_type_read((*))) enodev, \
+	(dev_type_write((*))) enodev, dev_init(c,n,ioctl), \
+	(dev_type_stop((*))) nullop, 0, selfalse, \
+	(dev_type_mmap((*))) enodev }
+
+/* open, close, ioctl */
 #define cdev_openprom_init(c,n) { \
 	dev_init(c,n,open), dev_init(c,n,close), (dev_type_read((*))) enodev, \
 	(dev_type_write((*))) enodev, dev_init(c,n,ioctl), \
 	(dev_type_stop((*))) nullop, 0, selfalse, \
 	(dev_type_mmap((*))) enodev }
 
+cdev_decl(kexec);
 cdev_decl(openprom);
diff --git a/sys/arch/powerpc64/include/kexec.h b/sys/arch/powerpc64/include/kexec.h
new file mode 100644
index 00000000000..ca018e00b0b
--- /dev/null
+++ b/sys/arch/powerpc64/include/kexec.h
@@ -0,0 +1,36 @@
+/*	$OpenBSD: kexec.h,v 1.1 2020/07/16 19:37:58 kettenis Exp $	*/
+
+/*
+ * Copyright (c) 2019-2020 Visa Hankala
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#ifndef _MACHINE_KEXEC_H_
+#define _MACHINE_KEXEC_H_
+
+#include <sys/ioccom.h>
+
+#define KEXEC_MAX_ARGS	8	/* maximum number of boot arguments */
+
+struct kexec_args {
+	char		*kimg;		/* kernel image buffer */
+	size_t		 klen;		/* size of kernel image */
+	char		*argv[KEXEC_MAX_ARGS];
+					/* kernel boot arguments */
+};
+
+#define KIOC_KEXEC		_IOW('K', 1, struct kexec_args)
+#define KIOC_GETBOOTDUID	_IOW('K', 2, char[8])
+
+#endif /* _MACHINE_KEXEC_H_ */
diff --git a/sys/arch/powerpc64/powerpc64/conf.c b/sys/arch/powerpc64/powerpc64/conf.c
index 34021ad6798..0165105b500 100644
--- a/sys/arch/powerpc64/powerpc64/conf.c
+++ b/sys/arch/powerpc64/powerpc64/conf.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: conf.c,v 1.8 2020/07/06 04:32:25 dlg Exp $	*/
+/*	$OpenBSD: conf.c,v 1.9 2020/07/16 19:37:58 kettenis Exp $	*/
 
 /*-
  * Copyright (c) 1991 The Regents of the University of California.
@@ -67,8 +67,9 @@ cdev_decl(com);
 #include "hotplug.h"
 #include "ipmi.h"
 #include "kcov.h"
-#include "ksyms.h"
+#include "kexec.h"
 #include "kstat.h"
+#include "ksyms.h"
 #include "lpt.h"
 cdev_decl(lpt);
 #include "midi.h"
@@ -117,7 +118,7 @@ struct cdevsw cdevsw[] =
 	cdev_dt_init(NDT,dt),		/* 13: dynamic tracer */
 	cdev_kcov_init(NKCOV,kcov),	/* 14: kcov */
 	cdev_kstat_init(NKSTAT,kstat),	/* 15: kernel statistics */
-	cdev_notdef(),			/* 16 */
+	cdev_kexec_init(NKEXEC,kexec),	/* 16: kexec */
 	cdev_notdef(),			/* 17 */
 	cdev_notdef(),			/* 18 */
 	cdev_notdef(),			/* 19 */