linux-user: Show heap address in /proc/pid/maps

Commit Message

Helge Deller Aug. 4, 2023, 8:46 a.m. UTC

Show the memory location of the heap in the /proc/pid/maps file inside
the guest. Store the heap address in ts->heap_base, which requires to
make that variable accessible for all guest architectures, not just
architectures for semihosted binaries (arm, m68k, riscv).

Show 32- and 64-bit pointers with 8 digits and leading zeros (%08x/%08lx).
For 64-bit we could use %16lx, but we mimic the Linux kernel, which shows
even 64-bit addresses with %08lx.

Example:

user@machine:/# uname -a
Linux paq 5.15.88+ #47 SMP Sun Jan 15 12:53:11 CET 2023 aarch64 GNU/Linux

user@machine:/# cat /proc/self/maps
Linux p100 6.4.4-200.fc38.x86_64 #1 SMP PREEMPT_DYNAMIC Wed Jul 19 16:32:49 UTC 2023 aarch64 GNU/Linux
5500000000-5500009000 r-xp 00000000 fd:00 570430                         /usr/bin/cat
5500009000-550001f000 ---p 00000000 00:00 0
550001f000-5500020000 r--p 0000f000 fd:00 570430                         /usr/bin/cat
5500020000-5500021000 rw-p 00010000 fd:00 570430                         /usr/bin/cat
5500021000-5500042000 rw-p 00000000 00:00 0                              [heap]
7000000000-7000001000 ---p 00000000 00:00 0
7000001000-7000801000 rw-p 00000000 00:00 0                              [stack]
7000801000-7000827000 r-xp 00000000 fd:00 571555                         /usr/lib/aarch64-linux-gnu/ld-linux-aarch64.so.1
7000827000-700083f000 ---p 00000000 00:00 0
700083f000-7000841000 r--p 0002e000 fd:00 571555                         /usr/lib/aarch64-linux-gnu/ld-linux-aarch64.so.1
7000841000-7000843000 rw-p 00030000 fd:00 571555                         /usr/lib/aarch64-linux-gnu/ld-linux-aarch64.so.1
7000843000-7000844000 r-xp 00000000 00:00 0
7000844000-7000846000 rw-p 00000000 00:00 0
7000850000-70009d7000 r-xp 00000000 fd:00 571558                         /usr/lib/aarch64-linux-gnu/libc.so.6
70009d7000-70009ed000 ---p 00187000 fd:00 571558                         /usr/lib/aarch64-linux-gnu/libc.so.6
70009ed000-70009f0000 r--p 0018d000 fd:00 571558                         /usr/lib/aarch64-linux-gnu/libc.so.6
70009f0000-70009f2000 rw-p 00190000 fd:00 571558                         /usr/lib/aarch64-linux-gnu/libc.so.6

Signed-off-by: Helge Deller <[e-mail]>
---
 include/exec/cpu_ldst.h | 4 ++--
 linux-user/main.c       | 1 +
 linux-user/qemu.h       | 4 ++--
 linux-user/syscall.c    | 8 ++++++--
 4 files changed, 11 insertions(+), 6 deletions(-)

--
2.41.0

Patch

diff --git a/include/exec/cpu_ldst.h b/include/exec/cpu_ldst.h
index 645476f0e5..f1e6f31e88 100644
--- a/include/exec/cpu_ldst.h
+++ b/include/exec/cpu_ldst.h
@@ -72,10 +72,10 @@ 
  */
 #if TARGET_VIRT_ADDR_SPACE_BITS <= 32
 typedef uint32_t abi_ptr;
-#define TARGET_ABI_FMT_ptr "%x"
+#define TARGET_ABI_FMT_ptr "%08x"
 #else
 typedef uint64_t abi_ptr;
-#define TARGET_ABI_FMT_ptr "%"PRIx64
+#define TARGET_ABI_FMT_ptr "%08"PRIx64
 #endif

 #ifndef TARGET_TAGGED_ADDRESSES
diff --git a/linux-user/main.c b/linux-user/main.c
index 51ee8649e2..c1838f5d4f 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -986,6 +986,7 @@  int main(int argc, char **argv, char **envp)
        the real value of GUEST_BASE into account.  */
     tcg_prologue_init(tcg_ctx);

+    ts->heap_base = info->brk;
     target_cpu_copy_regs(env, regs);

     if (gdbstub) {
diff --git a/linux-user/qemu.h b/linux-user/qemu.h
index 4f8b55e2fb..6d08453124 100644
--- a/linux-user/qemu.h
+++ b/linux-user/qemu.h
@@ -119,11 +119,11 @@  typedef struct TaskState {
 #ifdef TARGET_M68K
     abi_ulong tp_value;
 #endif
-#if defined(TARGET_ARM) || defined(TARGET_M68K) || defined(TARGET_RISCV)
+
     /* Extra fields for semihosted binaries.  */
     abi_ulong heap_base;
     abi_ulong heap_limit;
-#endif
+
     abi_ulong stack_base;
     int used; /* non zero if used */
     struct image_info *info;
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 7c2c2f6e2f..beba1c9cde 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -8090,14 +8090,18 @@  static int open_self_maps_1(CPUArchState *cpu_env, int fd, bool smaps)
                 continue;
             }

+            path = e->path;
+
+            if (ts->heap_base && h2g(min) == ts->heap_base) {
+                path = "[heap]";
+            }
+
 #ifdef TARGET_HPPA
             if (h2g(max) == ts->info->stack_limit) {
 #else
             if (h2g(min) == ts->info->stack_limit) {
 #endif
                 path = "[stack]";
-            } else {
-                path = e->path;
             }

             count = dprintf(fd, TARGET_ABI_FMT_ptr "-" TARGET_ABI_FMT_ptr