Move initial stack-pointer adjustment into assembly

bootstrap code. Avoids need for indirection thru
reset_stack_and_jump() in C code (which was incorrect for
secondary CPUs since nothing was pushed on the stack on
that initial call, hence the masking operation had no
effect and we ended up running on a bogus stack pointer).

Signed-off-by: Keir Fraser <keir@xensource.com>

4 files changed, 14 insertions, 29 deletions

diff --git a/xen/arch/x86/boot/x86_32.S b/xen/arch/x86/boot/x86_32.S
index d510c1fa1b..b98e1c72bc 100644
--- a/xen/arch/x86/boot/x86_32.S
+++ b/xen/arch/x86/boot/x86_32.S
@@ -1,5 +1,6 @@
 #include <xen/config.h>
 #include <public/xen.h>
+#include <asm/asm_defns.h>
 #include <asm/desc.h>
 #include <asm/page.h>
 #include <asm/msr.h>
@@ -53,6 +54,7 @@ __start:
         mov     %ecx,%gs
         ljmp    $(__HYPERVISOR_CS),$(1f)-__PAGE_OFFSET
 1:      lss     stack_start-__PAGE_OFFSET,%esp
+        add     $(STACK_SIZE-CPUINFO_sizeof-__PAGE_OFFSET),%esp
 
         /* Reset EFLAGS (subsumes CLI and CLD). */
 	pushl	$0
@@ -167,7 +169,7 @@ no_execute_disable:
         lidt    idt_descr
                 
         cmp     $(SECONDARY_CPU_FLAG),%ebx
-        je      init_secondary
+        je      start_secondary
 
         /* Call into main C routine. This should never return.*/
        	call	__start_xen
@@ -189,7 +191,7 @@ ignore_int:
 /*** STACK LOCATION ***/
         
 ENTRY(stack_start)
-        .long cpu0_stack + STACK_SIZE - __PAGE_OFFSET
+        .long cpu0_stack
         .long __HYPERVISOR_DS
         
 /*** DESCRIPTOR TABLES ***/
diff --git a/xen/arch/x86/boot/x86_64.S b/xen/arch/x86/boot/x86_64.S
index d89b7bf51a..3ab012aad8 100644
--- a/xen/arch/x86/boot/x86_64.S
+++ b/xen/arch/x86/boot/x86_64.S
@@ -1,5 +1,6 @@
 #include <xen/config.h>
 #include <public/xen.h>
+#include <asm/asm_defns.h>
 #include <asm/desc.h>
 #include <asm/page.h>
 #include <asm/msr.h>
@@ -121,7 +122,8 @@ skip_boot_checks:
         mov     %rcx,%cr4
 
         mov     stack_start(%rip),%rsp
-        
+        or      $(STACK_SIZE-CPUINFO_sizeof),%rsp
+
         /* Reset EFLAGS (subsumes CLI and CLD). */
         pushq   $0
         popf
@@ -140,9 +142,9 @@ __high_start:
         mov     %ecx,%ss
 
         lidt    idt_descr(%rip)
-                
+
         cmp     $(SECONDARY_CPU_FLAG),%ebx
-        je      init_secondary
+        je      start_secondary
 
         /* Initialize BSS (no nasty surprises!) */
         lea     __bss_start(%rip),%rdi
@@ -219,7 +221,7 @@ idt:
         .quad   idt_table
 
 ENTRY(stack_start)
-        .quad   cpu0_stack + STACK_SIZE
+        .quad   cpu0_stack
 
 high_start:
         .quad   __high_start
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index f39a43c185..38fb25d16e 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -142,9 +142,7 @@ static void __init do_initcalls(void)
 
 static struct e820entry e820_raw[E820MAX];
 
-static multiboot_info_t *mbi;
-
-void __init start_of_day(void)
+void __init __start_xen(multiboot_info_t *mbi)
 {
     unsigned long vgdt, gdt_pfn;
     char *cmdline;
@@ -561,12 +559,6 @@ void __init start_of_day(void)
     startup_cpu_idle_loop();
 }
 
-void __init __start_xen(multiboot_info_t *__mbi)
-{
-    mbi = __mbi;
-    reset_stack_and_jump(start_of_day);
-}
-
 void arch_get_xen_caps(xen_capabilities_info_t info)
 {
     char *p = info;
diff --git a/xen/arch/x86/smpboot.c b/xen/arch/x86/smpboot.c
index 96117b0727..30ca4864b2 100644
--- a/xen/arch/x86/smpboot.c
+++ b/xen/arch/x86/smpboot.c
@@ -429,7 +429,7 @@ static void construct_percpu_idt(unsigned int cpu)
 /*
  * Activate a secondary processor.
  */
-void __init start_secondary(void)
+void __init start_secondary(void *unused)
 {
 	unsigned int cpu = cpucount;
 
@@ -472,11 +472,6 @@ void __init start_secondary(void)
 	startup_cpu_idle_loop();
 }
 
-void __init init_secondary(void)
-{
-    reset_stack_and_jump(start_secondary);
-}
-
 extern struct {
 	void * esp;
 	unsigned short ss;
@@ -768,7 +763,6 @@ static int __init do_boot_cpu(int apicid)
 {
 	struct domain *idle;
 	struct vcpu *v;
-	void *stack;
 	unsigned long boot_error;
 	int timeout, cpu;
 	unsigned long start_eip;
@@ -791,15 +785,10 @@ static int __init do_boot_cpu(int apicid)
 	/* So we see what's up   */
 	printk("Booting processor %d/%d eip %lx\n", cpu, apicid, start_eip);
 
-	stack = alloc_xenheap_pages(STACK_ORDER);
-#if defined(__i386__)
-	stack_start.esp = (void *)__pa(stack) + STACK_SIZE;
-#elif defined(__x86_64__)
-	stack_start.esp = stack + STACK_SIZE;
-#endif
+	stack_start.esp = alloc_xenheap_pages(STACK_ORDER);
 
 	/* Debug build: detect stack overflow by setting up a guard page. */
-	memguard_guard_stack(stack);
+	memguard_guard_stack(stack_start.esp);
 
 	/*
 	 * This grunge runs the startup process for