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authorMeador Inge <meadori@codesourcery.com>2012-07-26 16:50:01 +0000
committerPeter Maydell <peter.maydell@linaro.org>2012-08-14 20:26:55 +0100
commitdce104013d1b393d39a89c4417d7771d928c08f3 (patch)
treeb626753ce53025a28859fb6c94562ed6bd27d451
parentcd8e407d24657569e0d6e323b2e8c274fafab590 (diff)
downloadqemu-arm-dce104013d1b393d39a89c4417d7771d928c08f3.tar.gz
linux-user: Factor out guest space probing into a function
Signed-off-by: Meador Inge <meadori@codesourcery.com> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
-rw-r--r--linux-user/elfload.c110
-rw-r--r--linux-user/qemu.h13
2 files changed, 90 insertions, 33 deletions
diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index 6b622d4ff9..cbc7617765 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -1426,6 +1426,73 @@ bool guest_validate_base(unsigned long guest_base)
}
#endif
+unsigned long init_guest_space(unsigned long host_start,
+ unsigned long host_size,
+ unsigned long guest_start,
+ bool fixed)
+{
+ unsigned long current_start, real_start;
+ int flags;
+
+ assert(host_start || host_size);
+
+ /* 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 - guest_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)
{
@@ -1452,46 +1519,23 @@ 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, loaddr, false);
+ 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 7b299b7bc3..7d4e23e4c1 100644
--- a/linux-user/qemu.h
+++ b/linux-user/qemu.h
@@ -210,6 +210,19 @@ 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. The guest_start parameter
+ * specifies the start address of the guest space. guest_base will be the
+ * difference between the host start address computed by this function and
+ * guest_start. If fixed is specified, then the mapped address space must
+ * start at host_start. The real start address of the mapped memory space is
+ * returned or -1 if there was an error.
+ */
+unsigned long init_guest_space(unsigned long host_start,
+ unsigned long host_size,
+ unsigned long guest_start,
+ bool fixed);
+
#include "qemu-log.h"
/* strace.c */