Factor out duplicated code from dumpsys() on each architecture into generic

code in sys/kern/kern_dump.c. Most dumpsys() implementations are nearly
identical and simply redefine a number of constants and helper subroutines;
a generic implementation will make it easier to implement features around
kernel core dumps. This change does not alter any minidump code and should
have no functional impact.

PR:		193873
Differential Revision:	https://reviews.freebsd.org/D904
Submitted by:	Conrad Meyer <conrad.meyer@isilon.com>
Reviewed by:	jhibbits (earlier version)
Sponsored by:	EMC / Isilon Storage Division

1 files changed, 393 insertions, 0 deletions

diff --git a/sys/kern/kern_dump.c b/sys/kern/kern_dump.c
new file mode 100644
index 000000000000..b33247c51033
--- /dev/null
+++ b/sys/kern/kern_dump.c
@@ -0,0 +1,393 @@
+/*-
+ * Copyright (c) 2002 Marcel Moolenaar
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include "opt_watchdog.h"
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/conf.h>
+#include <sys/cons.h>
+#include <sys/kernel.h>
+#include <sys/proc.h>
+#include <sys/kerneldump.h>
+#ifdef SW_WATCHDOG
+#include <sys/watchdog.h>
+#endif
+#include <vm/vm.h>
+#include <vm/vm_param.h>
+#include <vm/pmap.h>
+#include <machine/dump.h>
+#include <machine/elf.h>
+#include <machine/md_var.h>
+#include <machine/pcb.h>
+
+CTASSERT(sizeof(struct kerneldumpheader) == 512);
+
+/*
+ * Don't touch the first SIZEOF_METADATA bytes on the dump device. This
+ * is to protect us from metadata and to protect metadata from us.
+ */
+#define	SIZEOF_METADATA		(64*1024)
+
+#define	MD_ALIGN(x)	(((off_t)(x) + PAGE_MASK) & ~PAGE_MASK)
+#define	DEV_ALIGN(x)	(((off_t)(x) + (DEV_BSIZE-1)) & ~(DEV_BSIZE-1))
+
+off_t dumplo;
+
+/* Handle buffered writes. */
+static char buffer[DEV_BSIZE];
+static size_t fragsz;
+
+struct dump_pa dump_map[DUMPSYS_MD_PA_NPAIRS];
+
+void
+dumpsys_gen_pa_init(void)
+{
+#if !defined(__sparc__) && !defined(__powerpc__)
+	int n, idx;
+
+	bzero(dump_map, sizeof(dump_map));
+	for (n = 0; n < sizeof(dump_map) / sizeof(dump_map[0]); n++) {
+		idx = n * 2;
+		if (dump_avail[idx] == 0 && dump_avail[idx + 1] == 0)
+			break;
+		dump_map[n].pa_start = dump_avail[idx];
+		dump_map[n].pa_size = dump_avail[idx + 1] - dump_avail[idx];
+	}
+#endif
+}
+
+struct dump_pa *
+dumpsys_gen_pa_next(struct dump_pa *mdp)
+{
+
+	if (mdp == NULL)
+		return (&dump_map[0]);
+
+	mdp++;
+	if (mdp->pa_size == 0)
+		mdp = NULL;
+	return (mdp);
+}
+
+void
+dumpsys_gen_wbinv_all(void)
+{
+}
+
+void
+dumpsys_gen_unmap_chunk(vm_paddr_t pa __unused, size_t chunk __unused,
+    void *va __unused)
+{
+}
+
+int
+dumpsys_gen_write_aux_headers(struct dumperinfo *di)
+{
+
+	return (0);
+}
+
+int
+dumpsys_buf_write(struct dumperinfo *di, char *ptr, size_t sz)
+{
+	size_t len;
+	int error;
+
+	while (sz) {
+		len = DEV_BSIZE - fragsz;
+		if (len > sz)
+			len = sz;
+		bcopy(ptr, buffer + fragsz, len);
+		fragsz += len;
+		ptr += len;
+		sz -= len;
+		if (fragsz == DEV_BSIZE) {
+			error = dump_write(di, buffer, 0, dumplo,
+			    DEV_BSIZE);
+			if (error)
+				return (error);
+			dumplo += DEV_BSIZE;
+			fragsz = 0;
+		}
+	}
+	return (0);
+}
+
+int
+dumpsys_buf_flush(struct dumperinfo *di)
+{
+	int error;
+
+	if (fragsz == 0)
+		return (0);
+
+	error = dump_write(di, buffer, 0, dumplo, DEV_BSIZE);
+	dumplo += DEV_BSIZE;
+	fragsz = 0;
+	return (error);
+}
+
+CTASSERT(PAGE_SHIFT < 20);
+#define PG2MB(pgs) ((pgs + (1 << (20 - PAGE_SHIFT)) - 1) >> (20 - PAGE_SHIFT))
+
+int
+dumpsys_cb_dumpdata(struct dump_pa *mdp, int seqnr, void *arg)
+{
+	struct dumperinfo *di = (struct dumperinfo*)arg;
+	vm_paddr_t pa;
+	void *va;
+	uint64_t pgs;
+	size_t counter, sz, chunk;
+	int c, error;
+	u_int maxdumppgs;
+
+	error = 0;	/* catch case in which chunk size is 0 */
+	counter = 0;	/* Update twiddle every 16MB */
+	va = 0;
+	pgs = mdp->pa_size / PAGE_SIZE;
+	pa = mdp->pa_start;
+	maxdumppgs = min(di->maxiosize / PAGE_SIZE, MAXDUMPPGS);
+	if (maxdumppgs == 0)	/* seatbelt */
+		maxdumppgs = 1;
+
+	printf("  chunk %d: %juMB (%ju pages)", seqnr, (uintmax_t)PG2MB(pgs),
+	    (uintmax_t)pgs);
+
+	dumpsys_wbinv_all();
+	while (pgs) {
+		chunk = pgs;
+		if (chunk > maxdumppgs)
+			chunk = maxdumppgs;
+		sz = chunk << PAGE_SHIFT;
+		counter += sz;
+		if (counter >> 24) {
+			printf(" %ju", (uintmax_t)PG2MB(pgs));
+			counter &= (1 << 24) - 1;
+		}
+
+		dumpsys_map_chunk(pa, chunk, &va);
+#ifdef SW_WATCHDOG
+		wdog_kern_pat(WD_LASTVAL);
+#endif
+
+		error = dump_write(di, va, 0, dumplo, sz);
+		dumpsys_unmap_chunk(pa, chunk, va);
+		if (error)
+			break;
+		dumplo += sz;
+		pgs -= chunk;
+		pa += sz;
+
+		/* Check for user abort. */
+		c = cncheckc();
+		if (c == 0x03)
+			return (ECANCELED);
+		if (c != -1)
+			printf(" (CTRL-C to abort) ");
+	}
+	printf(" ... %s\n", (error) ? "fail" : "ok");
+	return (error);
+}
+
+int
+dumpsys_foreach_chunk(dumpsys_callback_t cb, void *arg)
+{
+	struct dump_pa *mdp;
+	int error, seqnr;
+
+	seqnr = 0;
+	mdp = dumpsys_pa_next(NULL);
+	while (mdp != NULL) {
+		error = (*cb)(mdp, seqnr++, arg);
+		if (error)
+			return (-error);
+		mdp = dumpsys_pa_next(mdp);
+	}
+	return (seqnr);
+}
+
+static off_t fileofs;
+
+static int
+cb_dumphdr(struct dump_pa *mdp, int seqnr, void *arg)
+{
+	struct dumperinfo *di = (struct dumperinfo*)arg;
+	Elf_Phdr phdr;
+	uint64_t size;
+	int error;
+
+	size = mdp->pa_size;
+	bzero(&phdr, sizeof(phdr));
+	phdr.p_type = PT_LOAD;
+	phdr.p_flags = PF_R;			/* XXX */
+	phdr.p_offset = fileofs;
+#ifdef __powerpc__
+	phdr.p_vaddr = (do_minidump? mdp->pa_start : ~0L);
+	phdr.p_paddr = (do_minidump? ~0L : mdp->pa_start);
+#else
+	phdr.p_vaddr = mdp->pa_start;
+	phdr.p_paddr = mdp->pa_start;
+#endif
+	phdr.p_filesz = size;
+	phdr.p_memsz = size;
+	phdr.p_align = PAGE_SIZE;
+
+	error = dumpsys_buf_write(di, (char*)&phdr, sizeof(phdr));
+	fileofs += phdr.p_filesz;
+	return (error);
+}
+
+static int
+cb_size(struct dump_pa *mdp, int seqnr, void *arg)
+{
+	uint64_t *sz;
+
+	sz = (uint64_t *)arg;
+	*sz += (uint64_t)mdp->pa_size;
+	return (0);
+}
+
+int
+dumpsys_generic(struct dumperinfo *di)
+{
+	static struct kerneldumpheader kdh;
+	Elf_Ehdr ehdr;
+	uint64_t dumpsize;
+	off_t hdrgap;
+	size_t hdrsz;
+	int error;
+
+#ifndef __powerpc__
+	if (do_minidump)
+		return (minidumpsys(di));
+#endif
+
+	bzero(&ehdr, sizeof(ehdr));
+	ehdr.e_ident[EI_MAG0] = ELFMAG0;
+	ehdr.e_ident[EI_MAG1] = ELFMAG1;
+	ehdr.e_ident[EI_MAG2] = ELFMAG2;
+	ehdr.e_ident[EI_MAG3] = ELFMAG3;
+	ehdr.e_ident[EI_CLASS] = ELF_CLASS;
+#if BYTE_ORDER == LITTLE_ENDIAN
+	ehdr.e_ident[EI_DATA] = ELFDATA2LSB;
+#else
+	ehdr.e_ident[EI_DATA] = ELFDATA2MSB;
+#endif
+	ehdr.e_ident[EI_VERSION] = EV_CURRENT;
+	ehdr.e_ident[EI_OSABI] = ELFOSABI_STANDALONE;	/* XXX big picture? */
+	ehdr.e_type = ET_CORE;
+	ehdr.e_machine = EM_VALUE;
+	ehdr.e_phoff = sizeof(ehdr);
+	ehdr.e_flags = 0;
+	ehdr.e_ehsize = sizeof(ehdr);
+	ehdr.e_phentsize = sizeof(Elf_Phdr);
+	ehdr.e_shentsize = sizeof(Elf_Shdr);
+
+	dumpsys_pa_init();
+
+	/* Calculate dump size. */
+	dumpsize = 0L;
+	ehdr.e_phnum = dumpsys_foreach_chunk(cb_size, &dumpsize) +
+	    DUMPSYS_NUM_AUX_HDRS;
+	hdrsz = ehdr.e_phoff + ehdr.e_phnum * ehdr.e_phentsize;
+	fileofs = MD_ALIGN(hdrsz);
+	dumpsize += fileofs;
+	hdrgap = fileofs - DEV_ALIGN(hdrsz);
+
+	/* Determine dump offset on device. */
+	if (di->mediasize < SIZEOF_METADATA + dumpsize + sizeof(kdh) * 2) {
+		error = ENOSPC;
+		goto fail;
+	}
+	dumplo = di->mediaoffset + di->mediasize - dumpsize;
+	dumplo -= sizeof(kdh) * 2;
+
+	mkdumpheader(&kdh, KERNELDUMPMAGIC, KERNELDUMP_ARCH_VERSION, dumpsize,
+	    di->blocksize);
+
+	printf("Dumping %ju MB (%d chunks)\n", (uintmax_t)dumpsize >> 20,
+	    ehdr.e_phnum - DUMPSYS_NUM_AUX_HDRS);
+
+	/* Dump leader */
+	error = dump_write(di, &kdh, 0, dumplo, sizeof(kdh));
+	if (error)
+		goto fail;
+	dumplo += sizeof(kdh);
+
+	/* Dump ELF header */
+	error = dumpsys_buf_write(di, (char*)&ehdr, sizeof(ehdr));
+	if (error)
+		goto fail;
+
+	/* Dump program headers */
+	error = dumpsys_foreach_chunk(cb_dumphdr, di);
+	if (error < 0)
+		goto fail;
+	error = dumpsys_write_aux_headers(di);
+	if (error < 0)
+		goto fail;
+	dumpsys_buf_flush(di);
+
+	/*
+	 * All headers are written using blocked I/O, so we know the
+	 * current offset is (still) block aligned. Skip the alignement
+	 * in the file to have the segment contents aligned at page
+	 * boundary. We cannot use MD_ALIGN on dumplo, because we don't
+	 * care and may very well be unaligned within the dump device.
+	 */
+	dumplo += hdrgap;
+
+	/* Dump memory chunks (updates dumplo) */
+	error = dumpsys_foreach_chunk(dumpsys_cb_dumpdata, di);
+	if (error < 0)
+		goto fail;
+
+	/* Dump trailer */
+	error = dump_write(di, &kdh, 0, dumplo, sizeof(kdh));
+	if (error)
+		goto fail;
+
+	/* Signal completion, signoff and exit stage left. */
+	dump_write(di, NULL, 0, 0, 0);
+	printf("\nDump complete\n");
+	return (0);
+
+ fail:
+	if (error < 0)
+		error = -error;
+
+	if (error == ECANCELED)
+		printf("\nDump aborted\n");
+	else if (error == ENOSPC)
+		printf("\nDump failed. Partition too small.\n");
+	else
+		printf("\n** DUMP FAILED (ERROR %d) **\n", error);
+	return (error);
+}