[PATCH v1 1/8] xen/riscv: make sure that identity mapping isn't bigger then page size

[Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>]

Signed-off-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
---
 xen/arch/riscv/xen.lds.S | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/xen/arch/riscv/xen.lds.S b/xen/arch/riscv/xen.lds.S
index 878130f313..74afbaab9b 100644
--- a/xen/arch/riscv/xen.lds.S
+++ b/xen/arch/riscv/xen.lds.S
@@ -20,6 +20,7 @@ SECTIONS
     . = XEN_VIRT_START;
     _start = .;
     .text : {
+        _idmap_start = .;
         _stext = .;            /* Text section */
         *(.text.header)
 
@@ -35,6 +36,7 @@ SECTIONS
         *(.gnu.warning)
         . = ALIGN(POINTER_ALIGN);
         _etext = .;             /* End of text section */
+        _idmap_end = .;
     } :text
 
     . = ALIGN(PAGE_SIZE);
@@ -174,3 +176,10 @@ ASSERT(!SIZEOF(.got),      ".got non-empty")
 ASSERT(!SIZEOF(.got.plt),  ".got.plt non-empty")
 
 ASSERT(_end - _start <= MB(2), "Xen too large for early-boot assumptions")
+
+/*
+ * We require that Xen is loaded at a page boundary, so this ensures that any
+ * code running on the identity map cannot cross a page boundary.
+ */
+ASSERT(IS_ALIGNED(_idmap_start, PAGE_SIZE), "_idmap_start should be 
page-aligned")
+ASSERT(_idmap_end - _idmap_start <= PAGE_SIZE, "Identity mapped code is larger 
than a page size")
-- 
2.40.1