Add 4Kn kernel dump support

(And 4Kn minidump support, but only for amd64.)

Make sure all I/O to the dump device is of the native sector size.  To
that end, we keep a native sector sized buffer associated with dump
devices (di->blockbuf) and use it to pad smaller objects as needed (e.g.
kerneldumpheader).

Add dump_write_pad() as a convenience API to dump smaller objects with
zero padding.  (Rather than pull in NPM leftpad, we wrote our own.)

Savecore(1) has been updated to deal with these dumps.  The format for
512-byte sector dumps should remain backwards compatible.

Minidumps for other architectures are left as an exercise for the
reader.

PR:		194279
Submitted by:	ambrisko@
Reviewed by:	cem (earlier version), rpokala
Tested by:	rpokala (4Kn/512 except 512 fulldump), cem (512 fulldump)
Relnotes:	yes
Sponsored by:	EMC / Isilon Storage Division
Differential Revision:	https://reviews.freebsd.org/D5848

1 files changed, 7 insertions, 9 deletions

diff --git a/sys/amd64/amd64/minidump_machdep.c b/sys/amd64/amd64/minidump_machdep.c
index cc32cdc..df04f42 100644
--- a/sys/amd64/amd64/minidump_machdep.c
+++ b/sys/amd64/amd64/minidump_machdep.c
@@ -56,9 +56,6 @@ CTASSERT(sizeof(struct kerneldumpheader) == 512);
  */
 #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))
-
 uint64_t *vm_page_dump;
 int vm_page_dump_size;
 
@@ -222,6 +219,7 @@ minidumpsys(struct dumperinfo *di)
 	int error;
 	uint64_t bits;
 	uint64_t *pml4, *pdp, *pd, *pt, pa;
+	size_t size;
 	int i, ii, j, k, n, bit;
 	int retry_count;
 	struct minidumphdr mdhdr;
@@ -319,12 +317,12 @@ minidumpsys(struct dumperinfo *di)
 	dumpsize += PAGE_SIZE;
 
 	/* Determine dump offset on device. */
-	if (di->mediasize < SIZEOF_METADATA + dumpsize + sizeof(kdh) * 2) {
+	if (di->mediasize < SIZEOF_METADATA + dumpsize + di->blocksize * 2) {
 		error = E2BIG;
 		goto fail;
 	}
 	dumplo = di->mediaoffset + di->mediasize - dumpsize;
-	dumplo -= sizeof(kdh) * 2;
+	dumplo -= di->blocksize * 2;
 	progress = dumpsize;
 
 	/* Initialize mdhdr */
@@ -344,10 +342,10 @@ minidumpsys(struct dumperinfo *di)
 	    ptoa((uintmax_t)physmem) / 1048576);
 
 	/* Dump leader */
-	error = dump_write(di, &kdh, 0, dumplo, sizeof(kdh));
+	error = dump_write_pad(di, &kdh, 0, dumplo, sizeof(kdh), &size);
 	if (error)
 		goto fail;
-	dumplo += sizeof(kdh);
+	dumplo += size;
 
 	/* Dump my header */
 	bzero(&fakepd, sizeof(fakepd));
@@ -432,10 +430,10 @@ minidumpsys(struct dumperinfo *di)
 		goto fail;
 
 	/* Dump trailer */
-	error = dump_write(di, &kdh, 0, dumplo, sizeof(kdh));
+	error = dump_write_pad(di, &kdh, 0, dumplo, sizeof(kdh), &size);
 	if (error)
 		goto fail;
-	dumplo += sizeof(kdh);
+	dumplo += size;
 
 	/* Signal completion, signoff and exit stage left. */
 	dump_write(di, NULL, 0, 0, 0);