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authorPaul Brook <paul@codesourcery.com>2009-07-17 12:48:08 +0100
committerPaul Brook <paul@codesourcery.com>2009-07-17 13:12:41 +0100
commit379f6698d73f476de38682b3ff96ecb226728c43 (patch)
tree35ec0c77416322f16fa27d646af50c60363168e3 /linux-user
parenta9ff9df188615d653a5a904bafbe724d40143e35 (diff)
Userspace guest address offsetting
Re-implement GUEST_BASE support. Offset guest ddress space by default if the guest binary contains regions below the host mmap_min_addr. Implement support for i386, x86-64 and arm hosts. Signed-off-by: Riku Voipio <riku.voipio@iki.fi> Signed-off-by: Paul Brook <paul@codesourcery.com>
Diffstat (limited to 'linux-user')
-rw-r--r--linux-user/elfload.c23
-rw-r--r--linux-user/main.c45
-rw-r--r--linux-user/qemu.h3
3 files changed, 71 insertions, 0 deletions
diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index d31cca71d1..d4c9274206 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -1545,6 +1545,29 @@ int load_elf_binary(struct linux_binprm * bprm, struct target_pt_regs * regs,
info->mmap = 0;
elf_entry = (abi_ulong) elf_ex.e_entry;
+#if defined(CONFIG_USE_GUEST_BASE)
+ /*
+ * In case where user has not explicitly set the guest_base, we
+ * probe here that should we set it automatically.
+ */
+ if (!have_guest_base) {
+ /*
+ * Go through ELF program header table and find out whether
+ * any of the segments drop below our current mmap_min_addr and
+ * in that case set guest_base to corresponding address.
+ */
+ for (i = 0, elf_ppnt = elf_phdata; i < elf_ex.e_phnum;
+ i++, elf_ppnt++) {
+ if (elf_ppnt->p_type != PT_LOAD)
+ continue;
+ if (HOST_PAGE_ALIGN(elf_ppnt->p_vaddr) < mmap_min_addr) {
+ guest_base = HOST_PAGE_ALIGN(mmap_min_addr);
+ break;
+ }
+ }
+ }
+#endif /* CONFIG_USE_GUEST_BASE */
+
/* Do this so that we can load the interpreter, if need be. We will
change some of these later */
info->rss = 0;
diff --git a/linux-user/main.c b/linux-user/main.c
index 9038b58e7e..4388c04c9a 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -39,6 +39,11 @@
char *exec_path;
int singlestep;
+#if defined(CONFIG_USE_GUEST_BASE)
+unsigned long mmap_min_addr;
+unsigned long guest_base;
+int have_guest_base;
+#endif
static const char *interp_prefix = CONFIG_QEMU_PREFIX;
const char *qemu_uname_release = CONFIG_UNAME_RELEASE;
@@ -2320,6 +2325,9 @@ static void usage(void)
"-E var=value sets/modifies targets environment variable(s)\n"
"-U var unsets targets environment variable(s)\n"
"-0 argv0 forces target process argv[0] to be argv0\n"
+#if defined(CONFIG_USE_GUEST_BASE)
+ "-B address set guest_base address to address\n"
+#endif
"\n"
"Debug options:\n"
"-d options activate log (logfile=%s)\n"
@@ -2495,6 +2503,11 @@ int main(int argc, char **argv, char **envp)
#endif
exit(1);
}
+#if defined(CONFIG_USE_GUEST_BASE)
+ } else if (!strcmp(r, "B")) {
+ guest_base = strtol(argv[optind++], NULL, 0);
+ have_guest_base = 1;
+#endif
} else if (!strcmp(r, "drop-ld-preload")) {
(void) envlist_unsetenv(envlist, "LD_PRELOAD");
} else if (!strcmp(r, "singlestep")) {
@@ -2572,6 +2585,35 @@ int main(int argc, char **argv, char **envp)
target_environ = envlist_to_environ(envlist, NULL);
envlist_free(envlist);
+#if defined(CONFIG_USE_GUEST_BASE)
+ /*
+ * Now that page sizes are configured in cpu_init() we can do
+ * proper page alignment for guest_base.
+ */
+ guest_base = HOST_PAGE_ALIGN(guest_base);
+
+ /*
+ * Read in mmap_min_addr kernel parameter. This value is used
+ * When loading the ELF image to determine whether guest_base
+ * is needed.
+ *
+ * When user has explicitly set the quest base, we skip this
+ * test.
+ */
+ if (!have_guest_base) {
+ FILE *fp;
+
+ if ((fp = fopen("/proc/sys/vm/mmap_min_addr", "r")) != NULL) {
+ unsigned long tmp;
+ if (fscanf(fp, "%lu", &tmp) == 1) {
+ mmap_min_addr = tmp;
+ qemu_log("host mmap_min_addr=0x%lx\n", mmap_min_addr);
+ }
+ fclose(fp);
+ }
+ }
+#endif /* CONFIG_USE_GUEST_BASE */
+
/*
* Prepare copy of argv vector for target.
*/
@@ -2622,6 +2664,9 @@ int main(int argc, char **argv, char **envp)
free(target_environ);
if (qemu_log_enabled()) {
+#if defined(CONFIG_USE_GUEST_BASE)
+ qemu_log("guest_base 0x%lx\n", guest_base);
+#endif
log_page_dump();
qemu_log("start_brk 0x" TARGET_ABI_FMT_lx "\n", info->start_brk);
diff --git a/linux-user/qemu.h b/linux-user/qemu.h
index 83ad443c23..8e728a3d28 100644
--- a/linux-user/qemu.h
+++ b/linux-user/qemu.h
@@ -133,6 +133,9 @@ void init_task_state(TaskState *ts);
void task_settid(TaskState *);
void stop_all_tasks(void);
extern const char *qemu_uname_release;
+#if defined(CONFIG_USE_GUEST_BASE)
+extern unsigned long mmap_min_addr;
+#endif
/* ??? See if we can avoid exposing so much of the loader internals. */
/*