Don't need two 16K static buffers to checksum the GPT entries and find the

OpenBSD partition. Just one 128-byte stack copy of a single entry.

Problems with EFI installs involving many disks reported by and fix
tested by Thomas Bohl.

Stefan Kempf pointed finger of suspicion at the addition of the 2nd
16K static buffer for softraid GPT and suggested/reviewed several
versions of the diff.

Tweaked and ok jsing@

1 files changed, 23 insertions, 19 deletions

diff --git a/sys/arch/amd64/stand/efiboot/efidev.c b/sys/arch/amd64/stand/efiboot/efidev.c
index 62dd84b7f11..e6bd1014305 100644
--- a/sys/arch/amd64/stand/efiboot/efidev.c
+++ b/sys/arch/amd64/stand/efiboot/efidev.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: efidev.c,v 1.14 2015/12/24 21:37:25 krw Exp $	*/
+/*	$OpenBSD: efidev.c,v 1.15 2016/01/03 15:01:31 krw Exp $	*/
 
 /*
  * Copyright (c) 1996 Michael Shalayeff
@@ -292,14 +292,14 @@ findopenbsd_gpt(efi_diskinfo_t ed, const char **err)
 {
 	EFI_STATUS		 status;
 	struct			 gpt_header gh;
-	int			 i, part;
+	int			 i, part, found;
 	uint64_t		 lba;
 	uint32_t		 orig_csum, new_csum;
 	uint32_t		 ghsize, ghpartsize, ghpartnum, ghpartspersec;
+	uint32_t		 gpsectors;
 	const char		 openbsd_uuid_code[] = GPT_UUID_OPENBSD;
+	struct gpt_partition	 gp;
 	static struct uuid	*openbsd_uuid = NULL, openbsd_uuid_space;
-	static struct gpt_partition
-				 gp[NGPTPARTITIONS];
 	static u_char		 buf[4096];
 
 	/* Prepare OpenBSD UUID */
@@ -363,28 +363,32 @@ findopenbsd_gpt(efi_diskinfo_t ed, const char **err)
 	ghpartsize = letoh32(gh.gh_part_size);
 	ghpartspersec = ed->blkio->Media->BlockSize / ghpartsize;
 	ghpartnum = letoh32(gh.gh_part_num);
-	for (i = 0; i < (ghpartnum + ghpartspersec - 1) / ghpartspersec;
-	    i++, lba++) {
+	gpsectors = (ghpartnum + ghpartspersec - 1) / ghpartspersec;
+	new_csum = crc32(0L, Z_NULL, 0);
+	found = 0;
+	for (i = 0; i < gpsectors; i++, lba++) {
 		status = efid_io(F_READ, ed, EFI_SECTOBLK(ed, lba),
 		    EFI_BLKSPERSEC(ed), buf);
 		if (EFI_ERROR(status)) {
 			*err = "Disk I/O Error";
 			return (-1);
 		}
-		memcpy(gp + i * ghpartspersec, buf,
-		    ghpartspersec * sizeof(struct gpt_partition));
-	}
-	new_csum = crc32(0, (unsigned char *)&gp, ghpartnum * ghpartsize);
-	if (new_csum != letoh32(gh.gh_part_csum)) {
-		*err = "bad GPT partitions checksum\n";
-		return (-1);
-	}
-
-	for (part = 0; part < ghpartnum; part++) {
-		if (memcmp(&gp[part].gp_type, openbsd_uuid,
-		    sizeof(struct uuid)) == 0)
-			return letoh64(gp[part].gp_lba_start);
+		for (part = 0; part < ghpartspersec; part++) {
+			if (ghpartnum == 0)
+				break;
+			new_csum = crc32(new_csum, buf + part * sizeof(gp),
+			    sizeof(gp));
+			ghpartnum--;
+			if (found)
+				continue;
+			memcpy(&gp, buf + part * sizeof(gp), sizeof(gp));
+			if (memcmp(&gp.gp_type, openbsd_uuid,
+			    sizeof(struct uuid)) == 0)
+				found = 1;
+		}
 	}
+	if (found && new_csum == letoh32(gh.gh_part_csum))
+		return letoh64(gp.gp_lba_start);
 
 	return (-1);
 }