Disable SMAP temporarily to display userland traces.

ok visa@, deraadt@, mlarkin@, jasper@

diff --git a/sys/arch/amd64/amd64/db_trace.c b/sys/arch/amd64/amd64/db_trace.c
index 8783f4c..f3234a7 100644 (file)
--- a/sys/arch/amd64/amd64/db_trace.c
+++ b/sys/arch/amd64/amd64/db_trace.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: db_trace.c,v 1.36 2017/11/03 11:29:46 jasper Exp $    */
+/*     $OpenBSD: db_trace.c,v 1.37 2017/12/08 08:54:03 mpi Exp $       */
 /*     $NetBSD: db_trace.c,v 1.1 2003/04/26 18:39:27 fvdl Exp $        */
 
 /*
@@ -169,9 +169,11 @@ db_stack_trace_print(db_expr_t addr, boolean_t have_addr, db_expr_t count,
        struct callframe *frame, *lastframe;
        unsigned long   *argp, *arg0;
        db_addr_t       callpc;
+       unsigned int    cr4save = CR4_SMEP|CR4_SMAP;
        int             is_trap = 0;
        boolean_t       kernel_only = TRUE;
        boolean_t       trace_proc = FALSE;
+       struct proc     *p;
 
        {
                char *cp = modif;
@@ -185,22 +187,30 @@ db_stack_trace_print(db_expr_t addr, boolean_t have_addr, db_expr_t count,
                }
        }
 
+       if (trace_proc) {
+               p = tfind((pid_t)addr);
+               if (p == NULL) {
+                       (*pr) ("not found\n");
+                       return;
+               }
+       }
+
+       cr4save = rcr4();
+       if (cr4save & CR4_SMAP)
+               lcr4(cr4save & ~CR4_SMAP);
+
        if (!have_addr) {
                frame = (struct callframe *)ddb_regs.tf_rbp;
                callpc = (db_addr_t)ddb_regs.tf_rip;
+       } else if (trace_proc) {
+               frame = (struct callframe *)p->p_addr->u_pcb.pcb_rbp;
+               callpc = (db_addr_t)
+                   db_get_value((db_addr_t)&frame->f_retaddr, 8, FALSE);
+               frame = (struct callframe *)frame->f_frame;
        } else {
-               if (trace_proc) {
-                       struct proc *p = tfind((pid_t)addr);
-                       if (p == NULL) {
-                               (*pr) ("not found\n");
-                               return;
-                       }
-                       frame = (struct callframe *)p->p_addr->u_pcb.pcb_rbp;
-               } else {
-                       frame = (struct callframe *)addr;
-               }
+               frame = (struct callframe *)addr;
                callpc = (db_addr_t)
-                        db_get_value((db_addr_t)&frame->f_retaddr, 8, FALSE);
+                   db_get_value((db_addr_t)&frame->f_retaddr, 8, FALSE);
                frame = (struct callframe *)frame->f_frame;
        }
 
@@ -212,8 +222,13 @@ db_stack_trace_print(db_expr_t addr, boolean_t have_addr, db_expr_t count,
                db_expr_t       offset;
                Elf_Sym *       sym;
 
-               sym = db_search_symbol(callpc, DB_STGY_ANY, &offset);
-               db_symbol_values(sym, &name, NULL);
+               if (INKERNEL(frame)) {
+                       sym = db_search_symbol(callpc, DB_STGY_ANY, &offset);
+                       db_symbol_values(sym, &name, NULL);
+               } else {
+                       sym = NULL;
+                       name = NULL;
+               }
 
                if (lastframe == 0 && sym == NULL) {
                        /* Symbol not found, peek at code */
@@ -332,6 +347,9 @@ db_stack_trace_print(db_expr_t addr, boolean_t have_addr, db_expr_t count,
                db_printsym(callpc, DB_STGY_XTRN, pr);
                (*pr)(":\n");
        }
+
+       if (cr4save & CR4_SMAP)
+               lcr4(cr4save);
 }
 
 void

diff --git a/sys/arch/i386/i386/db_trace.c b/sys/arch/i386/i386/db_trace.c
index 8d7156b..0e5289f 100644 (file)
--- a/sys/arch/i386/i386/db_trace.c
+++ b/sys/arch/i386/i386/db_trace.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: db_trace.c,v 1.31 2017/11/03 11:29:46 jasper Exp $    */
+/*     $OpenBSD: db_trace.c,v 1.32 2017/12/08 08:54:03 mpi Exp $       */
 /*     $NetBSD: db_trace.c,v 1.18 1996/05/03 19:42:01 christos Exp $   */
 
 /*
@@ -184,18 +184,17 @@ db_stack_trace_print(db_expr_t addr, boolean_t have_addr, db_expr_t count,
        struct callframe *frame, *lastframe;
        int             *argp, *arg0;
        db_addr_t       callpc;
+       unsigned int    cr4save = CR4_SMEP|CR4_SMAP;
        int             is_trap = 0;
        boolean_t       kernel_only = TRUE;
-       boolean_t       trace_thread = FALSE;
        boolean_t       trace_proc = FALSE;
+       struct proc     *p;
 
        {
                char *cp = modif;
                char c;
 
                while ((c = *cp++) != 0) {
-                       if (c == 't')
-                               trace_thread = TRUE;
                        if (c == 'p')
                                trace_proc = TRUE;
                        if (c == 'u')
@@ -206,24 +205,33 @@ db_stack_trace_print(db_expr_t addr, boolean_t have_addr, db_expr_t count,
        if (count == -1)
                count = 65535;
 
-       if (!have_addr) {
-               frame = (struct callframe *)ddb_regs.tf_ebp;
-               callpc = (db_addr_t)ddb_regs.tf_eip;
-       } else if (trace_thread) {
-               (*pr) ("%s: can't trace thread\n", __func__);
-       } else if (trace_proc) {
-               struct proc *p = tfind((pid_t)addr);
+       if (trace_proc) {
+               p = tfind((pid_t)addr);
                if (p == NULL) {
                        (*pr) ("not found\n");
                        return;
                }
+       }
+
+       if (curcpu()->ci_feature_sefflags_ebx & SEFF0EBX_SMAP) {
+               cr4save = rcr4();
+               if (cr4save & CR4_SMAP)
+                       lcr4(cr4save & ~CR4_SMAP);
+       } else {
+               cr4save = 0;
+       }
+
+       if (!have_addr) {
+               frame = (struct callframe *)ddb_regs.tf_ebp;
+               callpc = (db_addr_t)ddb_regs.tf_eip;
+       } else if (trace_proc) {
                frame = (struct callframe *)p->p_addr->u_pcb.pcb_ebp;
                callpc = (db_addr_t)
                    db_get_value((int)&frame->f_retaddr, 4, FALSE);
        } else {
                frame = (struct callframe *)addr;
                callpc = (db_addr_t)
-                        db_get_value((int)&frame->f_retaddr, 4, FALSE);
+                   db_get_value((int)&frame->f_retaddr, 4, FALSE);
        }
 
        lastframe = 0;
@@ -233,8 +241,13 @@ db_stack_trace_print(db_expr_t addr, boolean_t have_addr, db_expr_t count,
                db_expr_t       offset;
                Elf_Sym         *sym;
 
-               sym = db_search_symbol(callpc, DB_STGY_ANY, &offset);
-               db_symbol_values(sym, &name, NULL);
+               if (INKERNEL(frame)) {
+                       sym = db_search_symbol(callpc, DB_STGY_ANY, &offset);
+                       db_symbol_values(sym, &name, NULL);
+               } else {
+                       sym = NULL;
+                       name = NULL;
+               }
 
                if (lastframe == 0 && sym == NULL) {
                        /* Symbol not found, peek at code */
@@ -306,8 +319,10 @@ db_stack_trace_print(db_expr_t addr, boolean_t have_addr, db_expr_t count,
                        }
                } else if (INKERNEL(lastframe)) {
                        /* switch from user to kernel */
-                       if (kernel_only)
+                       if (kernel_only) {
+                               (*pr)("end of kernel\n");
                                break;  /* kernel stack only */
+                       }
                } else {
                        /* in user */
                        if (frame <= lastframe) {
@@ -323,6 +338,9 @@ db_stack_trace_print(db_expr_t addr, boolean_t have_addr, db_expr_t count,
                db_printsym(callpc, DB_STGY_XTRN, pr);
                (*pr)(":\n");
        }
+
+       if (cr4save & CR4_SMAP)
+               lcr4(cr4save);
 }
 
 void