linux-user: Pass last not end to probe_guest_base

Pass the address of the last byte of the image, rather than
the first address past the last byte.  This avoids overflow
when the last page of the address space is involved.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

linux-user/elfload.c

@@ -2504,7 +2504,7 @@ static void pgb_have_guest_base(const char *image_name, abi_ulong guest_loaddr,
         if (guest_hiaddr > reserved_va) {
             error_report("%s: requires more than reserved virtual "
                          "address space (0x%" PRIx64 " > 0x%lx)",
-                         image_name, (uint64_t)guest_hiaddr, reserved_va);
+                         image_name, (uint64_t)guest_hiaddr + 1, reserved_va);
             exit(EXIT_FAILURE);
         }
     } else {
@@ -2512,7 +2512,7 @@ static void pgb_have_guest_base(const char *image_name, abi_ulong guest_loaddr,
         if ((guest_hiaddr - guest_base) > ~(uintptr_t)0) {
             error_report("%s: requires more virtual address space "
                          "than the host can provide (0x%" PRIx64 ")",
-                         image_name, (uint64_t)guest_hiaddr - guest_base);
+                         image_name, (uint64_t)guest_hiaddr + 1 - guest_base);
             exit(EXIT_FAILURE);
         }
 #endif
@@ -2525,18 +2525,18 @@ static void pgb_have_guest_base(const char *image_name, abi_ulong guest_loaddr,
     if (reserved_va) {
         guest_loaddr = (guest_base >= mmap_min_addr ? 0
                         : mmap_min_addr - guest_base);
-        guest_hiaddr = reserved_va;
+        guest_hiaddr = reserved_va - 1;
     }
 
     /* Reserve the address space for the binary, or reserved_va. */
     test = g2h_untagged(guest_loaddr);
-    addr = mmap(test, guest_hiaddr - guest_loaddr, PROT_NONE, flags, -1, 0);
+    addr = mmap(test, guest_hiaddr - guest_loaddr + 1, PROT_NONE, flags, -1, 0);
     if (test != addr) {
         pgb_fail_in_use(image_name);
     }
     qemu_log_mask(CPU_LOG_PAGE,
-                  "%s: base @ %p for " TARGET_ABI_FMT_ld " bytes\n",
-                  __func__, addr, guest_hiaddr - guest_loaddr);
+                  "%s: base @ %p for %" PRIu64 " bytes\n",
+                  __func__, addr, (uint64_t)guest_hiaddr - guest_loaddr + 1);
 }
 
 /**
@@ -2680,7 +2680,7 @@ static void pgb_static(const char *image_name, abi_ulong orig_loaddr,
     if (hiaddr != orig_hiaddr) {
         error_report("%s: requires virtual address space that the "
                      "host cannot provide (0x%" PRIx64 ")",
-                     image_name, (uint64_t)orig_hiaddr);
+                     image_name, (uint64_t)orig_hiaddr + 1);
         exit(EXIT_FAILURE);
     }
 
@@ -2694,7 +2694,7 @@ static void pgb_static(const char *image_name, abi_ulong orig_loaddr,
          * arithmetic wraps around.
          */
         if (sizeof(uintptr_t) == 8 || loaddr >= 0x80000000u) {
-            hiaddr = (uintptr_t) 4 << 30;
+            hiaddr = UINT32_MAX;
         } else {
             offset = -(HI_COMMPAGE & -align);
         }
@@ -2702,7 +2702,7 @@ static void pgb_static(const char *image_name, abi_ulong orig_loaddr,
         loaddr = MIN(loaddr, LO_COMMPAGE & -align);
     }
 
-    addr = pgb_find_hole(loaddr, hiaddr - loaddr, align, offset);
+    addr = pgb_find_hole(loaddr, hiaddr - loaddr + 1, align, offset);
     if (addr == -1) {
         /*
          * If HI_COMMPAGE, there *might* be a non-consecutive allocation
@@ -2755,7 +2755,7 @@ static void pgb_reserved_va(const char *image_name, abi_ulong guest_loaddr,
     if (guest_hiaddr > reserved_va) {
         error_report("%s: requires more than reserved virtual "
                      "address space (0x%" PRIx64 " > 0x%lx)",
-                     image_name, (uint64_t)guest_hiaddr, reserved_va);
+                     image_name, (uint64_t)guest_hiaddr + 1, reserved_va);
         exit(EXIT_FAILURE);
     }
 
@@ -3021,7 +3021,7 @@ static void load_elf_image(const char *image_name, int image_fd,
             if (a < loaddr) {
                 loaddr = a;
             }
-            a = eppnt->p_vaddr + eppnt->p_memsz;
+            a = eppnt->p_vaddr + eppnt->p_memsz - 1;
             if (a > hiaddr) {
                 hiaddr = a;
             }
@@ -3112,7 +3112,7 @@ static void load_elf_image(const char *image_name, int image_fd,
      * In both cases, we will overwrite pages in this range with mappings
      * from the executable.
      */
-    load_addr = target_mmap(loaddr, hiaddr - loaddr, PROT_NONE,
+    load_addr = target_mmap(loaddr, (size_t)hiaddr - loaddr + 1, PROT_NONE,
                             MAP_PRIVATE | MAP_ANON | MAP_NORESERVE |
                             (ehdr->e_type == ET_EXEC ? MAP_FIXED : 0),
                             -1, 0);

linux-user/flatload.c

@@ -448,7 +448,7 @@ static int load_flat_file(struct linux_binprm * bprm,
      * Allocate the address space.
      */
     probe_guest_base(bprm->filename, 0,
-                     text_len + data_len + extra + indx_len);
+                     text_len + data_len + extra + indx_len - 1);
 
     /*
      * there are a couple of cases here,  the separate code/data

linux-user/user-internals.h

@@ -76,19 +76,19 @@ void fork_end(int child);
 /**
  * probe_guest_base:
  * @image_name: the executable being loaded
- * @loaddr: the lowest fixed address in the executable
- * @hiaddr: the highest fixed address in the executable
+ * @loaddr: the lowest fixed address within the executable
+ * @hiaddr: the highest fixed address within the executable
  *
  * Creates the initial guest address space in the host memory space.
  *
- * If @loaddr == 0, then no address in the executable is fixed,
- * i.e. it is fully relocatable.  In that case @hiaddr is the size
- * of the executable.
+ * If @loaddr == 0, then no address in the executable is fixed, i.e.
+ * it is fully relocatable.  In that case @hiaddr is the size of the
+ * executable minus one.
  *
  * This function will not return if a valid value for guest_base
  * cannot be chosen.  On return, the executable loader can expect
  *
- *    target_mmap(loaddr, hiaddr - loaddr, ...)
+ *    target_mmap(loaddr, hiaddr - loaddr + 1, ...)
  *
  * to succeed.
  */