From: Andrew Cooper <andrew.cooper3@citrix.com>
Date: Thu, 22 Mar 2018 11:50:50 +0000 (+0000)
Subject: Use a linker ASSERT() to check that the mappings are within l1_identmap[]
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=1ae15cb320a59276c2333ee20fef7c7549ffc0f7;p=xtf.git

Use a linker ASSERT() to check that the mappings are within l1_identmap[]

This avoids needing the runtime checks in hvm's arch_init_traps()

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---

diff --git a/arch/x86/hvm/traps.c b/arch/x86/hvm/traps.c
index 9d732e6..96374aa 100644
--- a/arch/x86/hvm/traps.c
+++ b/arch/x86/hvm/traps.c
@@ -133,17 +133,11 @@ void arch_init_traps(void)
     {
         unsigned long gfn = virt_to_gfn(user_stack);
 
-        if ( gfn >= ARRAY_SIZE(l1_identmap) )
-            panic("user_stack[] outside of l1_identmap[]\n");
-
         l1_identmap[gfn] |= _PAGE_USER;
 
         extern const char __start_user_text[], __end_user_text[];
         unsigned long end = virt_to_gfn(__end_user_text);
 
-        if ( gfn >= ARRAY_SIZE(l1_identmap) )
-            panic("__{start,end}_user_text[] outside of l1_identmap[]\n");
-
         for ( gfn = virt_to_gfn(__start_user_text); gfn < end; ++gfn )
             l1_identmap[gfn] |= _PAGE_USER;
 
diff --git a/arch/x86/link.lds.S b/arch/x86/link.lds.S
index 03c9455..db77d35 100644
--- a/arch/x86/link.lds.S
+++ b/arch/x86/link.lds.S
@@ -92,6 +92,9 @@ ASSERT(IS_ALIGNED(__end_user_text,   PAGE_SIZE), "__end_user_text misaligned");
 
 #ifdef CONFIG_HVM
 
+/* Check everything lives within l1_identmap[] for user and r/o mappings. */
+ASSERT(_end < (1 << (PT_ORDER + PAGE_SHIFT)), "Mappings exceed l1_identmap[]");
+
 ASSERT(IS_ALIGNED(pae_l1_identmap, PAGE_SIZE), "pae_l1_identmap misaligned");
 ASSERT(IS_ALIGNED(pae_l2_identmap, PAGE_SIZE), "pae_l2_identmap misaligned");
 ASSERT(IS_ALIGNED(pae_l3_identmap, PAGE_SIZE), "pae_l3_identmap misaligned");