From 5b1de5204776284283019e18a3a45310c6e83be6 Mon Sep 17 00:00:00 2001
From: Peter Maydell <peter.maydell@linaro.org>
Date: Sun, 29 Nov 2020 20:39:20 +0000
Subject: [PATCH] hw/core/loader.c: Track last-seen ROM in
 rom_check_and_register_reset()

In rom_check_and_register_reset() we detect overlaps by looking at
whether the ROM blob we're currently examining is in the same address
space and starts before the previous ROM blob ends.  (This works
because the ROM list is kept sorted in order by AddressSpace and then
by address.)

Instead of keeping the AddressSpace and last address of the previous ROM
blob in local variables, just keep a pointer to it.

This will allow us to print more useful information when we do detect
an overlap.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20201129203923.10622-2-peter.maydell@linaro.org
---
 hw/core/loader.c | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/hw/core/loader.c b/hw/core/loader.c
index fea22d265c..45aaba6158 100644
--- a/hw/core/loader.c
+++ b/hw/core/loader.c
@@ -1166,28 +1166,35 @@ static void rom_reset(void *unused)
     }
 }
 
+/* Return true if two consecutive ROMs in the ROM list overlap */
+static bool roms_overlap(Rom *last_rom, Rom *this_rom)
+{
+    if (!last_rom) {
+        return false;
+    }
+    return last_rom->as == this_rom->as &&
+        last_rom->addr + last_rom->romsize > this_rom->addr;
+}
+
 int rom_check_and_register_reset(void)
 {
-    hwaddr addr = 0;
     MemoryRegionSection section;
-    Rom *rom;
-    AddressSpace *as = NULL;
+    Rom *rom, *last_rom = NULL;
 
     QTAILQ_FOREACH(rom, &roms, next) {
         if (rom->fw_file) {
             continue;
         }
         if (!rom->mr) {
-            if ((addr > rom->addr) && (as == rom->as)) {
+            if (roms_overlap(last_rom, rom)) {
                 fprintf(stderr, "rom: requested regions overlap "
                         "(rom %s. free=0x" TARGET_FMT_plx
                         ", addr=0x" TARGET_FMT_plx ")\n",
-                        rom->name, addr, rom->addr);
+                        rom->name, last_rom->addr + last_rom->romsize,
+                        rom->addr);
                 return -1;
             }
-            addr  = rom->addr;
-            addr += rom->romsize;
-            as = rom->as;
+            last_rom = rom;
         }
         section = memory_region_find(rom->mr ? rom->mr : get_system_memory(),
                                      rom->addr, 1);