linux-user: Fix executable page of /proc/self/maps

The guest binary and libraries are not always map with the
executable bit in the host process. The guest may read a
/proc/self/maps with no executable address range. The
perm fields should be based on the guest permission inside
Qemu.

Signed-off-by: Nicolas Surbayrole <nsurbayrole@quarkslab.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Acked-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20210308091959.986540-1-nsurbayrole@quarkslab.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>

linux-user/syscall.c

@@ -7890,9 +7890,9 @@ static int open_self_maps(void *cpu_env, int fd)
             count = dprintf(fd, TARGET_ABI_FMT_ptr "-" TARGET_ABI_FMT_ptr
                             " %c%c%c%c %08" PRIx64 " %s %"PRId64,
                             h2g(min), h2g(max - 1) + 1,
-                            e->is_read ? 'r' : '-',
-                            e->is_write ? 'w' : '-',
-                            e->is_exec ? 'x' : '-',
+                            (flags & PAGE_READ) ? 'r' : '-',
+                            (flags & PAGE_WRITE_ORG) ? 'w' : '-',
+                            (flags & PAGE_EXEC) ? 'x' : '-',
                             e->is_priv ? 'p' : '-',
                             (uint64_t) e->offset, e->dev, e->inode);
             if (path) {