Add "machine sysregs" command to DDB

From Alex Wilson, Thanks!

diff --git a/sys/arch/amd64/amd64/db_interface.c b/sys/arch/amd64/amd64/db_interface.c
index de64b05..186fb4d 100644 (file)
--- a/sys/arch/amd64/amd64/db_interface.c
+++ b/sys/arch/amd64/amd64/db_interface.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: db_interface.c,v 1.36 2021/05/30 15:05:32 visa Exp $  */
+/*     $OpenBSD: db_interface.c,v 1.37 2021/08/31 14:37:49 mlarkin Exp $       */
 /*     $NetBSD: db_interface.c,v 1.1 2003/04/26 18:39:27 fvdl Exp $    */
 
 /*
@@ -47,6 +47,7 @@
 #include <machine/cpuvar.h>
 #include <machine/i82093var.h>
 #include <machine/atomic.h>
+#include <machine/specialreg.h>
 
 #include <ddb/db_sym.h>
 #include <ddb/db_command.h>
@@ -161,6 +162,45 @@ db_ktrap(int type, int code, db_regs_t *regs)
        return (1);
 }
 
+void
+db_sysregs_cmd(db_expr_t addr, int have_addr, db_expr_t count, char *modif)
+{
+       int64_t idtr, gdtr;
+       uint64_t cr;
+       uint16_t ldtr, tr;
+       uint64_t gsb;
+
+       __asm__ volatile("sidt %0" : "=m" (idtr));
+       db_printf("idtr:   0x%08llx/%04llx\n", idtr >> 16, idtr & 0xffff);
+
+       __asm__ volatile("sgdt %0" : "=m" (gdtr));
+       db_printf("gdtr:   0x%08llx/%04llx\n", gdtr >> 16, gdtr & 0xffff);
+
+       __asm__ volatile("sldt %0" : "=g" (ldtr));
+       db_printf("ldtr:   0x%04x\n", ldtr);
+
+       __asm__ volatile("str %0" : "=g" (tr));
+       db_printf("tr:     0x%04x\n", tr);
+
+       __asm__ volatile("movq %%cr0,%0" : "=r" (cr));
+       db_printf("cr0:    0x%016llx\n", cr);
+
+       __asm__ volatile("movq %%cr2,%0" : "=r" (cr));
+       db_printf("cr2:    0x%016llx\n", cr);
+
+       __asm__ volatile("movq %%cr3,%0" : "=r" (cr));
+       db_printf("cr3:    0x%016llx\n", cr);
+
+       __asm__ volatile("movq %%cr4,%0" : "=r" (cr));
+       db_printf("cr4:    0x%016llx\n", cr);
+
+       gsb = rdmsr(MSR_GSBASE);
+       db_printf("gsb:    0x%016llx\n", gsb);
+
+       gsb = rdmsr(MSR_KERNELGSBASE);
+       db_printf("kgsb:   0x%016llx\n", gsb);
+}
+
 
 #ifdef MULTIPROCESSOR
 void
@@ -369,6 +409,7 @@ struct db_command db_machine_command_table[] = {
        { "startcpu",   db_startproc_cmd,       0,      0 },
        { "stopcpu",    db_stopproc_cmd,        0,      0 },
        { "ddbcpu",     db_ddbproc_cmd,         0,      0 },
+       { "sysregs",    db_sysregs_cmd,         0,      0 },
 #endif
 #if NACPI > 0
        { "acpi",       NULL,                   0,      db_acpi_cmds },