1 files changed, 56 insertions, 0 deletions

diff --git a/meta/recipes-devtools/qemu/qemu/0001-linux-user-x86_64-Handle-the-vsyscall-page-in-open_s.patch b/meta/recipes-devtools/qemu/qemu/0001-linux-user-x86_64-Handle-the-vsyscall-page-in-open_s.patch
new file mode 100644
index 0000000000..2eaebe883c
--- /dev/null
+++ b/meta/recipes-devtools/qemu/qemu/0001-linux-user-x86_64-Handle-the-vsyscall-page-in-open_s.patch
@@ -0,0 +1,56 @@
+From 4517e2046610722879761bcdb60edbb2b929c848 Mon Sep 17 00:00:00 2001
+From: Richard Henderson <richard.henderson@linaro.org>
+Date: Wed, 28 Feb 2024 10:25:14 -1000
+Subject: [PATCH 1/5] linux-user/x86_64: Handle the vsyscall page in
+ open_self_maps_{2,4}
+
+This is the only case in which we expect to have no host memory backing
+for a guest memory page, because in general linux user processes cannot
+map any pages in the top half of the 64-bit address space.
+
+Upstream-Status: Submitted [https://www.mail-archive.com/qemu-devel@nongnu.org/msg1026793.html]
+
+Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2170
+Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
+Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
+---
+ linux-user/syscall.c | 16 ++++++++++++++++
+ 1 file changed, 16 insertions(+)
+
+diff --git a/linux-user/syscall.c b/linux-user/syscall.c
+index a114f29a8..8307a8a61 100644
+--- a/linux-user/syscall.c
++++ b/linux-user/syscall.c
+@@ -7922,6 +7922,10 @@ static void open_self_maps_4(const struct open_self_maps_data *d,
+         path = "[heap]";
+     } else if (start == info->vdso) {
+         path = "[vdso]";
++#ifdef TARGET_X86_64
++    } else if (start == TARGET_VSYSCALL_PAGE) {
++        path = "[vsyscall]";
++#endif
+     }
+ 
+     /* Except null device (MAP_ANON), adjust offset for this fragment. */
+@@ -8010,6 +8014,18 @@ static int open_self_maps_2(void *opaque, target_ulong guest_start,
+     uintptr_t host_start = (uintptr_t)g2h_untagged(guest_start);
+     uintptr_t host_last = (uintptr_t)g2h_untagged(guest_end - 1);
+ 
++#ifdef TARGET_X86_64
++    /*
++     * Because of the extremely high position of the page within the guest
++     * virtual address space, this is not backed by host memory at all.
++     * Therefore the loop below would fail.  This is the only instance
++     * of not having host backing memory.
++     */
++    if (guest_start == TARGET_VSYSCALL_PAGE) {
++        return open_self_maps_3(opaque, guest_start, guest_end, flags);
++    }
++#endif
++
+     while (1) {
+         IntervalTreeNode *n =
+             interval_tree_iter_first(d->host_maps, host_start, host_start);
+-- 
+2.34.1
+