[PATCH v3 12/16] xenctx: Add -d <daddr> option to dump memory at daddr as a stack.

[Don Slutz <dslutz@verizon.com>]

From: Don Slutz <Don@CloudSwitch.com>

Also switch from read_stack_word to read_mem_word since the provided
address may not be aligned.

Signed-off-by: Don Slutz <Don@CloudSwitch.com>
---
Changed since v2:
  * Do this patch after -m patch.
  * Reworked option handling to allow multiple actions to work.
  * Add check for NO_TRANSLATION where needed.
  * More info in commit message.

 tools/xentrace/xenctx.c | 72 ++++++++++++++++++++++++++++++++++---------------
 1 file changed, 50 insertions(+), 22 deletions(-)

diff --git a/tools/xentrace/xenctx.c b/tools/xentrace/xenctx.c
index 98202f8..ee3dcb9 100644
--- a/tools/xentrace/xenctx.c
+++ b/tools/xentrace/xenctx.c
@@ -67,7 +67,9 @@ static struct xenctx {
     int all_vcpus;
 #ifndef NO_TRANSLATION
     guest_word_t mem_addr;
+    guest_word_t stk_addr;
     int do_memory;
+    int do_stack;
 #endif
     int self_paused;
     xc_dominfo_t dominfo;
@@ -728,15 +730,13 @@ static int print_code(vcpu_guest_context_any_t *ctx, int vcpu)
         else
             printf("%02x ", *c);
     }
-    printf("\n");
-
-    printf("\n");
+    printf("\n\n\n");
     return 0;
 }
 
-static int print_stack(vcpu_guest_context_any_t *ctx, int vcpu, int width)
+static int print_stack(vcpu_guest_context_any_t *ctx, int vcpu, int width, guest_word_t stk_addr_start)
 {
-    guest_word_t stack = stack_pointer(ctx);
+    guest_word_t stack = stk_addr_start;
     guest_word_t stack_limit;
     guest_word_t frame;
     guest_word_t word;
@@ -746,11 +746,10 @@ static int print_stack(vcpu_guest_context_any_t *ctx, int vcpu, int width)
 
     if (width)
         xenctx.bytes_per_line = ((xenctx.bytes_per_line + width - 1) / width) * width;
-    stack_limit = ((stack_pointer(ctx) + XC_PAGE_SIZE)
+    stack_limit = ((stack + XC_PAGE_SIZE)
                    & ~((guest_word_t) XC_PAGE_SIZE - 1));
     if (xenctx.two_pages)
         stack_limit += XC_PAGE_SIZE;
-    printf("\n");
     if (xenctx.lines) {
         printf("Stack:\n");
         for (i = 1; i < xenctx.lines + 1 && stack < stack_limit; i++) {
@@ -762,11 +761,11 @@ static int print_stack(vcpu_guest_context_any_t *ctx, int vcpu, int width)
                 printf(":");
             }
             while(stack < stack_limit &&
-                  stack < stack_pointer(ctx) + i * xenctx.bytes_per_line) {
+                  stack < stk_addr_start + i * xenctx.bytes_per_line) {
                 p = map_page(ctx, vcpu, stack);
                 if (!p)
                     return -1;
-                word = read_stack_word(p, width);
+                word = read_mem_word(ctx, vcpu, stack, width);
                 if (xenctx.decode_as_ascii)
                     ascii[j++] = word;
                 printf(" ");
@@ -799,14 +798,16 @@ static int print_stack(vcpu_guest_context_any_t *ctx, int vcpu, int width)
         printf("Stack Trace:\n");
     else
         printf("Call Trace:\n");
-    if (xenctx.tag_call_trace)
-        printf(" %*s", width*2, "");
-    printf("%c [<", xenctx.stack_trace ? '*' : ' ');
-    print_stack_word(instr_pointer(ctx), width);
-    printf(">]");
-
-    print_symbol(instr_pointer(ctx));
-    printf(" <--\n");
+    if (!xenctx.do_stack) {
+        if (xenctx.tag_call_trace)
+            printf(" %*s", width*2, "");
+        printf("%c [<", xenctx.stack_trace ? '*' : ' ');
+        print_stack_word(instr_pointer(ctx), width);
+        printf(">]");
+
+        print_symbol(instr_pointer(ctx));
+        printf(" <--\n");
+    }
     if (xenctx.frame_ptrs) {
         stack = stack_pointer(ctx);
         frame = frame_pointer(ctx);
@@ -865,12 +866,12 @@ static int print_stack(vcpu_guest_context_any_t *ctx, int vcpu, int width)
             }
         }
     } else {
-        stack = stack_pointer(ctx);
+        stack = stk_addr_start;
         while(stack < stack_limit) {
             p = map_page(ctx, vcpu, stack);
             if (!p)
                 return -1;
-            word = read_stack_word(p, width);
+            word = read_mem_word(ctx, vcpu, stack, width);
             if (is_kernel_text(word)) {
                 if (xenctx.tag_call_trace) {
                     print_stack_word(stack, width);
@@ -943,13 +944,17 @@ static void dump_ctx(int vcpu)
         print_mem(&ctx, vcpu, guest_word_size, xenctx.mem_addr);
         return;
     }
+    if (xenctx.do_stack) {
+        print_stack(&ctx, vcpu, guest_word_size, xenctx.stk_addr);
+        return;
+    }
 #endif
     print_ctx(&ctx);
 #ifndef NO_TRANSLATION
     if (print_code(&ctx, vcpu))
         return;
     if (is_kernel_text(instr_pointer(&ctx)))
-        if (print_stack(&ctx, vcpu, guest_word_size))
+        if (print_stack(&ctx, vcpu, guest_word_size, stack_pointer(&ctx)))
             return;
 #endif
 }
@@ -1000,6 +1005,8 @@ static void usage(void)
 #ifndef NO_TRANSLATION
     printf("  -m maddr, --memory=maddr\n");
     printf("                     dump memory at maddr.\n");
+    printf("  -d daddr, --dump-as-stack=daddr\n");
+    printf("                     dump memory as a stack at daddr.\n");
 #endif
 }
 
@@ -1008,7 +1015,7 @@ int main(int argc, char **argv)
     int ch;
     int ret;
 #ifndef NO_TRANSLATION
-    static const char *sopts = "fs:hak:SC2b:l:DtTm:";
+    static const char *sopts = "fs:hak:SC2b:l:DtTm:d:";
 #else
     static const char *sopts = "fs:hak:SC2b:l:DtT";
 #endif
@@ -1023,6 +1030,7 @@ int main(int argc, char **argv)
         {"tag-call-trace", 0, NULL, 'T'},
 #ifndef NO_TRANSLATION
         {"memory", 1, NULL, 'm'},
+        {"dump-as-stack", 1, NULL, 'd'},
 #endif
         {"bytes-per-line", 1, NULL, 'b'},
         {"lines", 1, NULL, 'l'},
@@ -1097,6 +1105,11 @@ int main(int argc, char **argv)
             xenctx.do_memory = 1;
             do_default = 0;
             break;
+        case 'd':
+            xenctx.stk_addr = strtoull(optarg, NULL, 0);
+            xenctx.do_stack = 1;
+            do_default = 0;
+            break;
 #endif
         case 'h':
             usage();
@@ -1114,6 +1127,15 @@ int main(int argc, char **argv)
         exit(-1);
     }
 
+#ifndef NO_TRANSLATION
+    if (xenctx.frame_ptrs && xenctx.do_stack) {
+        fprintf(stderr,
+                "%s both --frame-pointers and --dump-as-stack is not supported\n",
+                argv[0]);
+        exit(-1);
+    }
+#endif
+
     xenctx.domid = atoi(argv[0]);
     if (xenctx.domid==0) {
             fprintf(stderr, "cannot trace dom0\n");
@@ -1150,10 +1172,16 @@ int main(int argc, char **argv)
 #ifndef NO_TRANSLATION
     if (xenctx.do_memory) {
         dump_ctx(vcpu);
-        if (xenctx.all_vcpus)
+        if (xenctx.do_stack || xenctx.all_vcpus)
             printf("\n");
     }
     xenctx.do_memory = 0;
+    if (xenctx.do_stack) {
+        dump_ctx(vcpu);
+        if (xenctx.all_vcpus)
+            printf("\n");
+    }
+    xenctx.do_stack = 0;
 #endif
     if (xenctx.all_vcpus)
         dump_all_vcpus();
-- 
1.8.4