Provide private per-CPU GDTs on amd64. This is required at least for the

linux CB_GS32BIT to work.

Noted by:	nox
Reviewed by:	peter
MFC after:	1 week

2 files changed, 13 insertions, 5 deletions

diff --git a/sys/amd64/amd64/mp_machdep.c b/sys/amd64/amd64/mp_machdep.c
index 304deaa..5dc3228 100644
--- a/sys/amd64/amd64/mp_machdep.c
+++ b/sys/amd64/amd64/mp_machdep.c
@@ -436,7 +436,8 @@ init_secondary(void)
 {
 	struct pcpu *pc;
 	u_int64_t msr, cr0;
-	int cpu, gsel_tss;
+	int cpu, gsel_tss, x;
+	struct region_descriptor ap_gdt;
 
 	/* Set by the startup code for us to use */
 	cpu = bootAP;
@@ -447,11 +448,17 @@ init_secondary(void)
 	common_tss[cpu].tss_iobase = sizeof(struct amd64tss);
 	common_tss[cpu].tss_ist1 = (long)&doublefault_stack[PAGE_SIZE];
 
+	/* Prepare private GDT */
 	gdt_segs[GPROC0_SEL].ssd_base = (long) &common_tss[cpu];
 	ssdtosyssd(&gdt_segs[GPROC0_SEL],
-	   (struct system_segment_descriptor *)&gdt[GPROC0_SEL]);
-
-	lgdt(&r_gdt);			/* does magic intra-segment return */
+	   (struct system_segment_descriptor *)&gdt[NGDT * cpu + GPROC0_SEL]);
+	for (x = 0; x < NGDT; x++) {
+		if (x != GPROC0_SEL && x != (GPROC0_SEL + 1))
+			ssdtosd(&gdt_segs[x], &gdt[NGDT * cpu + x]);
+	}
+	ap_gdt.rd_limit = NGDT * sizeof(gdt[0]) - 1;
+	ap_gdt.rd_base =  (long) &gdt[NGDT * cpu];
+	lgdt(&ap_gdt);			/* does magic intra-segment return */
 
 	/* Get per-cpu data */
 	pc = &__pcpu[cpu];
diff --git a/sys/amd64/amd64/trap.c b/sys/amd64/amd64/trap.c
index 00e596f..8d710cd 100644
--- a/sys/amd64/amd64/trap.c
+++ b/sys/amd64/amd64/trap.c
@@ -692,7 +692,8 @@ trap_fatal(frame, eva)
 
 	code = frame->tf_err;
 	type = frame->tf_trapno;
-	sdtossd(&gdt[IDXSEL(frame->tf_cs & 0xffff)], &softseg);
+	sdtossd(&gdt[NGDT * PCPU_GET(cpuid) + IDXSEL(frame->tf_cs & 0xffff)],
+	    &softseg);
 
 	if (type <= MAX_TRAP_MSG)
 		msg = trap_msg[type];