Fix PPC symbol resolution

Summary:
There were 2 issues that were preventing correct symbol resolution
on PowerPC/pseries:

1- memory corruption at chrp_attach() - this caused the inital
   part of the symbol table to become zeroed, which would cause
   the kernel linker to fail to parse it.
   (this was probably zeroing out other memory parts as well)

2- DDB symbol resolution wasn't working because symtab contained
   not relocated addresses but it was given relocated offsets.
   Although relocating the symbol table fixed this, it broke the
   linker, that already handled this case.
   Thus, the fix for this consists in adding a new DDB macro:
   DB_STOFFS(offs) that converts a (potentially) relocated offset
   into one that can be compared with symbol table values.

PR:		227093
Submitted by:	Leandro Lupori <leandro.lupori_gmail.com>
Differential Revision: https://reviews.freebsd.org/D15372

2 files changed, 5 insertions, 1 deletions

diff --git a/sys/powerpc/include/db_machdep.h b/sys/powerpc/include/db_machdep.h
index c0dd7415bcbf..ff516c9b9942 100644
--- a/sys/powerpc/include/db_machdep.h
+++ b/sys/powerpc/include/db_machdep.h
@@ -85,4 +85,8 @@ typedef	intptr_t	db_expr_t;	/* expression - signed */
 #define	inst_load(ins)		0
 #define	inst_store(ins)		0
 
+#ifdef __powerpc64__
+#define DB_STOFFS(offs)		((offs) & ~DMAP_BASE_ADDRESS)
+#endif
+
 #endif	/* _POWERPC_DB_MACHDEP_H_ */
diff --git a/sys/powerpc/pseries/platform_chrp.c b/sys/powerpc/pseries/platform_chrp.c
index b85b19d05cb3..c254c0f5c425 100644
--- a/sys/powerpc/pseries/platform_chrp.c
+++ b/sys/powerpc/pseries/platform_chrp.c
@@ -146,7 +146,7 @@ chrp_attach(platform_t plat)
 
 		/* Set up important VPA fields */
 		for (i = 0; i < MAXCPU; i++) {
-			bzero(splpar_vpa[i], sizeof(splpar_vpa));
+			bzero(splpar_vpa[i], sizeof(splpar_vpa[i]));
 			/* First two: VPA size */
 			splpar_vpa[i][4] =
 			    (uint8_t)((sizeof(splpar_vpa[i]) >> 8) & 0xff);