Signed-off-by: Meador Inge <mead...@codesourcery.com>
---
linux-user/elfload.c | 111 +++++++++++++++++++++++++++++++++++---------------
linux-user/qemu.h | 11 +++++
2 files changed, 89 insertions(+), 33 deletions(-)
diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index f3b1552..44b4bdb 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -1385,6 +1385,74 @@ bool guest_validate_base(unsigned long guest_base)
}
#endif
+unsigned long init_guest_space(unsigned long host_start,
+ unsigned long host_size,
+ bool fixed)
+{
+ unsigned long current_start, real_start;
+ int flags;
+
+ /* Nothing to do here, move along. */
+ if (!host_start && !host_size) {
+ return 0;
+ }
+
+ /* If just a starting address is given, then just verify that
+ * address. */
+ if (host_start && !host_size) {
+ if (guest_validate_base(host_start)) {
+ return host_start;
+ } else {
+ return (unsigned long)-1;
+ }
+ }
+
+ /* Setup the initial flags and start address. */
+ current_start = host_start & qemu_host_page_mask;
+ flags = MAP_ANONYMOUS | MAP_PRIVATE | MAP_NORESERVE;
+ if (fixed) {
+ flags |= MAP_FIXED;
+ }
+
+ /* Otherwise, a non-zero size region of memory needs to be mapped
+ * and validated. */
+ while (1) {
+ /* Do not use mmap_find_vma here because that is limited to the
+ * guest address space. We are going to make the
+ * guest address space fit whatever we're given.
+ */
+ real_start = (unsigned long)
+ mmap((void *)current_start, host_size, PROT_NONE, flags, -1, 0);
+ if (real_start == (unsigned long)-1) {
+ return (unsigned long)-1;
+ }
+
+ if ((real_start == current_start) && guest_validate_base(real_start)) {
+ break;
+ }
+
+ /* That address didn't work. Unmap and try a different one.
+ * The address the host picked because is typically right at
+ * the top of the host address space and leaves the guest with
+ * no usable address space. Resort to a linear search. We
+ * already compensated for mmap_min_addr, so this should not
+ * happen often. Probably means we got unlucky and host
+ * address space randomization put a shared library somewhere
+ * inconvenient.
+ */
+ munmap((void *)real_start, host_size);
+ current_start += qemu_host_page_size;
+ if (host_start == current_start) {
+ /* Theoretically possible if host doesn't have any suitably
+ * aligned areas. Normally the first mmap will fail.
+ */
+ return (unsigned long)-1;
+ }
+ }
+
+ return real_start;
+}
+
static void probe_guest_base(const char *image_name,
abi_ulong loaddr, abi_ulong hiaddr)
{
@@ -1411,46 +1479,23 @@ static void probe_guest_base(const char *image_name,
}
}
host_size = hiaddr - loaddr;
- while (1) {
- /* Do not use mmap_find_vma here because that is limited to the
- guest address space. We are going to make the
- guest address space fit whatever we're given. */
- real_start = (unsigned long)
- mmap((void *)host_start, host_size, PROT_NONE,
- MAP_ANONYMOUS | MAP_PRIVATE | MAP_NORESERVE, -1, 0);
- if (real_start == (unsigned long)-1) {
- goto exit_perror;
- }
- guest_base = real_start - loaddr;
- if ((real_start == host_start) &&
- guest_validate_base(guest_base)) {
- break;
- }
- /* That address didn't work. Unmap and try a different one.
- The address the host picked because is typically right at
- the top of the host address space and leaves the guest with
- no usable address space. Resort to a linear search. We
- already compensated for mmap_min_addr, so this should not
- happen often. Probably means we got unlucky and host
- address space randomization put a shared library somewhere
- inconvenient. */
- munmap((void *)real_start, host_size);
- host_start += qemu_host_page_size;
- if (host_start == loaddr) {
- /* Theoretically possible if host doesn't have any suitably
- aligned areas. Normally the first mmap will fail. */
- errmsg = "Unable to find space for application";
- goto exit_errmsg;
- }
+
+ /* Setup the initial guest memory space with ranges gleaned from
+ * the ELF image that is being loaded.
+ */
+ real_start = init_guest_space(host_start, host_size, 0);
+ if (real_start == (unsigned long)-1) {
+ errmsg = "Unable to find space for application";
+ goto exit_errmsg;
}
+ guest_base = real_start - loaddr;
+
qemu_log("Relocating guest address space from 0x"
TARGET_ABI_FMT_lx " to 0x%lx\n",
loaddr, real_start);
}
return;
-exit_perror:
- errmsg = strerror(errno);
exit_errmsg:
fprintf(stderr, "%s: %s\n", image_name, errmsg);
exit(-1);
diff --git a/linux-user/qemu.h b/linux-user/qemu.h
index 7b299b7..c23dd8a 100644
--- a/linux-user/qemu.h
+++ b/linux-user/qemu.h
@@ -210,6 +210,17 @@ void fork_end(int child);
*/
bool guest_validate_base(unsigned long guest_base);
+/* Creates the initial guest address space in the host memory space using the
+ * given host start address hint and size. If fixed is specified, then the
+ * mapped address space must start at host_start. If host_start and host_size
+ * are both zero then nothing is done and zero is returned. Otherwise, the
+ * guest address space is initialized and the real start address of the mapped
+ * memory space is returned or -1 if there is was error.
+ */
+unsigned long init_guest_space(unsigned long host_start,
+ unsigned long host_size,
+ bool fixed);
+
#include "qemu-log.h"
/* strace.c */
--
1.7.7.6
