Explicitly declare the gdt storage in struct cpu_info_full instead of

implicitly putting it in the padding to page-size.  This eliminates a
couple Coverity issues from the Meltdown work.

testing daniel@
ok mlarkin@

5 files changed, 16 insertions, 12 deletions

diff --git a/sys/arch/amd64/amd64/cpu.c b/sys/arch/amd64/amd64/cpu.c
index 00f8b8bd79e..e2f9fc9ac79 100644
--- a/sys/arch/amd64/amd64/cpu.c
+++ b/sys/arch/amd64/amd64/cpu.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: cpu.c,v 1.113 2018/03/13 05:10:40 guenther Exp $	*/
+/*	$OpenBSD: cpu.c,v 1.114 2018/03/29 01:21:02 guenther Exp $	*/
 /* $NetBSD: cpu.c,v 1.1 2003/04/26 18:39:26 fvdl Exp $ */
 
 /*-
@@ -352,7 +352,7 @@ cpu_attach(struct device *parent, struct device *self, void *aux)
 		ci = &cif->cif_cpu;
 #if defined(MULTIPROCESSOR)
 		ci->ci_tss = &cif->cif_tss;
-		ci->ci_gdt = (void *)(ci->ci_tss + 1);
+		ci->ci_gdt = &cif->cif_gdt;
 		memcpy(ci->ci_gdt, cpu_info_primary.ci_gdt, GDT_SIZE);
 		cpu_enter_pages(cif);
 		if (cpu_info[cpunum] != NULL)
diff --git a/sys/arch/amd64/amd64/machdep.c b/sys/arch/amd64/amd64/machdep.c
index dd0623b15c4..b05455ab943 100644
--- a/sys/arch/amd64/amd64/machdep.c
+++ b/sys/arch/amd64/amd64/machdep.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: machdep.c,v 1.239 2018/02/21 19:24:15 guenther Exp $	*/
+/*	$OpenBSD: machdep.c,v 1.240 2018/03/29 01:21:02 guenther Exp $	*/
 /*	$NetBSD: machdep.c,v 1.3 2003/05/07 22:58:18 fvdl Exp $	*/
 
 /*-
@@ -1617,7 +1617,7 @@ init_x86_64(paddr_t first_avail)
 
 	idt = (struct gate_descriptor *)idt_vaddr;
 	cpu_info_primary.ci_tss = &cpu_info_full_primary.cif_tss;
-	cpu_info_primary.ci_gdt = (void *)(cpu_info_primary.ci_tss + 1);
+	cpu_info_primary.ci_gdt = &cpu_info_full_primary.cif_gdt;
 
 	/* make gdt gates and memory segments */
 	set_mem_segment(GDT_ADDR_MEM(cpu_info_primary.ci_gdt, GCODE_SEL), 0,
diff --git a/sys/arch/amd64/include/cpu.h b/sys/arch/amd64/include/cpu.h
index 8f973ba1423..f456c1a4681 100644
--- a/sys/arch/amd64/include/cpu.h
+++ b/sys/arch/amd64/include/cpu.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: cpu.h,v 1.119 2018/02/21 19:24:15 guenther Exp $	*/
+/*	$OpenBSD: cpu.h,v 1.120 2018/03/29 01:21:02 guenther Exp $	*/
 /*	$NetBSD: cpu.h,v 1.1 2003/04/26 18:39:39 fvdl Exp $	*/
 
 /*-
@@ -177,7 +177,7 @@ struct cpu_info {
 	struct x86_cache_info ci_cinfo[CAI_COUNT];
 
 	struct	x86_64_tss *ci_tss;
-	char		*ci_gdt;
+	void		*ci_gdt;
 
 	volatile int	ci_ddb_paused;
 #define CI_DDB_RUNNING		0
diff --git a/sys/arch/amd64/include/cpu_full.h b/sys/arch/amd64/include/cpu_full.h
index 93c433f44dd..6350a6b4ae5 100644
--- a/sys/arch/amd64/include/cpu_full.h
+++ b/sys/arch/amd64/include/cpu_full.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: cpu_full.h,v 1.2 2018/02/22 20:27:14 bluhm Exp $	*/
+/*	$OpenBSD: cpu_full.h,v 1.3 2018/03/29 01:21:02 guenther Exp $	*/
 /*
  * Copyright (c) Philip Guenther <guenther@openbsd.org>
  *
@@ -29,10 +29,14 @@
 struct cpu_info_full {
 	/* page mapped kRO in u-k */
 	union {
-		struct x86_64_tss	u_tss; /* followed by gdt */
+		struct {
+			struct x86_64_tss	uu_tss;
+			uint64_t		uu_gdt[GDT_SIZE / 8];
+		} u_tssgdt;
 		char			u_align[PAGE_SIZE];
 	} cif_RO;
-#define cif_tss	cif_RO.u_tss
+#define cif_tss	cif_RO.u_tssgdt.uu_tss
+#define cif_gdt	cif_RO.u_tssgdt.uu_gdt
 
 	/* start of page mapped kRW in u-k */
 	uint64_t cif_tramp_stack[(PAGE_SIZE / 4
diff --git a/sys/arch/amd64/include/segments.h b/sys/arch/amd64/include/segments.h
index 0c6c8609d05..6ce184e88d1 100644
--- a/sys/arch/amd64/include/segments.h
+++ b/sys/arch/amd64/include/segments.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: segments.h,v 1.14 2015/09/30 05:44:32 guenther Exp $	*/
+/*	$OpenBSD: segments.h,v 1.15 2018/03/29 01:21:02 guenther Exp $	*/
 /*	$NetBSD: segments.h,v 1.1 2003/04/26 18:39:47 fvdl Exp $	*/
 
 /*-
@@ -263,9 +263,9 @@ void cpu_init_idt(void);
 #define GDT_SYS_OFFSET	(NGDT_MEM << 3)
 
 #define GDT_ADDR_MEM(s,i)	\
-    ((struct mem_segment_descriptor *)((s) + ((i) << 3)))
+    ((struct mem_segment_descriptor *)((char *)(s) + ((i) << 3)))
 #define GDT_ADDR_SYS(s,i)	\
-   ((struct sys_segment_descriptor *)((s) + (((i) << 4) + SYSSEL_START)))
+    ((struct sys_segment_descriptor *)((char *)(s) + ((i) << 4) + SYSSEL_START))
 
 /*
  * Checks for valid user selectors.