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authorAndrew Cooper <andrew.cooper3@citrix.com>2013-08-27 11:28:26 +0200
committerJan Beulich <jbeulich@suse.com>2013-08-27 11:28:26 +0200
commit8a3c4acc9907cfec9aae9f1bc251fbf50af6828e (patch)
tree3e93a1da7124e4538579b65a894106e9ba0e01e0
parent483814219bc4d47db8a56116290ec7878b794c09 (diff)
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x86/boot: Explicitly clean pcpu stacks in debug builds
This reduces confusion when looking at a hexdump of the pcpu stacks and wondering were on earth some of the junk was coming from. Also leave some grep fodder for finding where the BSP switches stack (because it took me far longer to find than I care to admit to). Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
-rw-r--r--xen/arch/x86/boot/x86_64.S9
-rw-r--r--xen/arch/x86/smpboot.c4
2 files changed, 13 insertions, 0 deletions
diff --git a/xen/arch/x86/boot/x86_64.S b/xen/arch/x86/boot/x86_64.S
index ed3888d469..399541d19a 100644
--- a/xen/arch/x86/boot/x86_64.S
+++ b/xen/arch/x86/boot/x86_64.S
@@ -13,6 +13,15 @@
mov mmu_cr4_features(%rip),%rcx
mov %rcx,%cr4
+#ifndef NDEBUG
+ /* Clean stack. */
+ mov stack_start(%rip),%rdi
+ mov $(STACK_SIZE / 8),%rcx
+ xor %eax,%eax
+ rep stosq
+#endif
+
+ /* Switch to cpu0_stack. */
mov stack_start(%rip),%rsp
or $(STACK_SIZE-CPUINFO_sizeof),%rsp
diff --git a/xen/arch/x86/smpboot.c b/xen/arch/x86/smpboot.c
index 9f81c7ba62..8bfa151a40 100644
--- a/xen/arch/x86/smpboot.c
+++ b/xen/arch/x86/smpboot.c
@@ -659,6 +659,10 @@ static int cpu_smpboot_alloc(unsigned int cpu)
stack_base[cpu] = alloc_xenheap_pages(STACK_ORDER, 0);
if ( stack_base[cpu] == NULL )
goto oom;
+#ifndef NDEBUG
+ for ( order = 0 ; order < (1<<STACK_ORDER); ++order )
+ clear_page(stack_base[cpu] + order * PAGE_SIZE);
+#endif
memguard_guard_stack(stack_base[cpu]);
order = get_order_from_pages(NR_RESERVED_GDT_PAGES);