Eliminate hard coded items from x86_64 __xen_guest section

to avoid problems when the position of the hypercall page changes.
Further, clean up many things to avoid needless differences to native
code, while also adding a couple of adjustments that only will be
submitted for native code inclusion, that simplify code, or that
remove unused elements.

From: Jan Beulich <JBeulich@novell.com>
Signed-off-by: Christian Limpach <Christian.Limpach@cl.cam.ac.uk>

diff --git a/linux-2.6-xen-sparse/arch/x86_64/kernel/head-xen.S b/linux-2.6-xen-sparse/arch/x86_64/kernel/head-xen.S
index 6289c8a26f4079641bea5566b04efc5464b8ef9a..90769eee1d5798c497c3df1066c6ffebb7cb40ec 100644 (file)
--- a/linux-2.6-xen-sparse/arch/x86_64/kernel/head-xen.S
+++ b/linux-2.6-xen-sparse/arch/x86_64/kernel/head-xen.S
@@ -14,15 +14,6 @@
 
 
 #include <linux/linkage.h>
-
-.section __xen_guest
-       .ascii  "GUEST_OS=linux,GUEST_VER=2.6"
-       .ascii  ",XEN_VER=xen-3.0"
-       .ascii  ",VIRT_BASE=0xffffffff80000000"
-       .ascii  ",HYPERCALL_PAGE=0x10a" /* __pa(hypercall_page) >> 12 */
-       .ascii  ",LOADER=generic"
-       .byte   0
-      
 #include <linux/threads.h>
 #include <linux/init.h>
 #include <asm/desc.h>
@@ -30,64 +21,21 @@
 #include <asm/page.h>
 #include <asm/msr.h>
 #include <asm/cache.h>
-       
-/* we are not able to switch in one step to the final KERNEL ADRESS SPACE
- * because we need identity-mapped pages on setup so define __START_KERNEL to
- * 0x100000 for this stage
- * 
- */
 
        .text
        .code64
        .globl startup_64
 startup_64:
 ENTRY(_start)
-       movq %rsi,xen_start_info(%rip)
-
-#ifdef CONFIG_SMP
-ENTRY(startup_64_smp)
-#endif /* CONFIG_SMP */
-
-       cld
-
-       movq init_rsp(%rip),%rsp
+       movq $(init_thread_union+THREAD_SIZE-8),%rsp
        /* zero EFLAGS after setting rsp */
        pushq $0
        popfq
-       movq    initial_code(%rip),%rax
-       jmp     *%rax
-
-       /* SMP bootup changes these two */      
-       .globl  initial_code
-initial_code:
-       .quad   x86_64_start_kernel
-       .globl init_rsp
-init_rsp:
-       .quad  init_thread_union+THREAD_SIZE-8
-
-ENTRY(early_idt_handler)
-       xorl %eax,%eax
-       movq 8(%rsp),%rsi       # get rip
-       movq (%rsp),%rdx
-       leaq early_idt_msg(%rip),%rdi
-1:     hlt                     # generate #GP
-       jmp 1b
 
-early_idt_msg:
-       .asciz "PANIC: early exception rip %lx error %lx cr2 %lx\n"
-
-#if 0
-ENTRY(lgdt_finish)
-        movl $(__USER_DS),%eax          # DS/ES contains default USER segment
-        movw %ax,%ds
-        movw %ax,%es
-        movl $(__KERNEL_DS),%eax        
-        movw %ax,%ss                    # after changing gdt.
-        popq %rax                       # get the retrun address
-        pushq $(__KERNEL_CS)
-        pushq %rax
-        lretq
-#endif 
+       /* rsi is pointer to startup info structure.
+          pass it to C */
+       movq %rsi,%rdi
+       jmp x86_64_start_kernel
 
 ENTRY(stext)
 ENTRY(_stext)
@@ -113,39 +61,9 @@ NEXT_PAGE(init_level4_pgt)
 NEXT_PAGE(init_level4_user_pgt)
        .fill   512,8,0
 
-       /*
-        * In Xen the following pre-initialized pgt entries are re-initialized.
-        */
 NEXT_PAGE(level3_kernel_pgt)
-       .fill   510,8,0
-       /* (2^48-(2*1024*1024*1024)-((2^39)*511))/(2^30) = 510 */
-       .quad   phys_level2_kernel_pgt | 0x007
-       .fill   1,8,0
-
-NEXT_PAGE(level2_ident_pgt)
-       /* 40MB for bootup.     */
-       i = 0
-       .rept 20
-       .quad   i << 21 | 0x083
-       i = i + 1
-       .endr
-       /* Temporary mappings for the super early allocator in arch/x86_64/mm/init.c */
-       .globl temp_boot_pmds
-temp_boot_pmds:
-       .fill   492,8,0
+       .fill   512,8,0
 
-NEXT_PAGE(level2_kernel_pgt)
-       /* 40MB kernel mapping. The kernel code cannot be bigger than that.
-          When you change this change KERNEL_TEXT_SIZE in page.h too. */
-       /* (2^48-(2*1024*1024*1024)-((2^39)*511)-((2^30)*510)) = 0 */
-       i = 0
-       .rept 20
-       .quad   i << 21 | 0x183
-       i = i + 1
-       .endr
-       /* Module mapping starts here */
-       .fill   492,8,0
-       
         /*
          * This is used for vsyscall area mapping as we have a different
          * level4 page table for user.
@@ -153,81 +71,19 @@ NEXT_PAGE(level2_kernel_pgt)
 NEXT_PAGE(level3_user_pgt)
         .fill  512,8,0
 
-NEXT_PAGE(cpu_gdt_table)
-/* The TLS descriptors are currently at a different place compared to i386.
-   Hopefully nobody expects them at a fixed place (Wine?) */
-       .quad   0x0000000000000000      /* NULL descriptor */
-       .quad   0x0                     /* unused */
-       .quad   0x00affa000000ffff      /* __KERNEL_CS */
-       .quad   0x00cff2000000ffff      /* __KERNEL_DS */
-               .quad   0x00cffa000000ffff      /* __USER32_CS */
-       .quad   0x00cff2000000ffff      /* __USER_DS, __USER32_DS  */           
-       .quad   0x00affa000000ffff      /* __USER_CS */
-       .quad   0x00cffa000000ffff      /* __KERNEL32_CS */        
-       .quad   0,0                     /* TSS */
-       .quad   0,0                     /* LDT */
-       .quad   0,0,0                   /* three TLS descriptors */ 
-       .quad   0                       /* unused */
-gdt_end:
-#if 0
-       /* asm/segment.h:GDT_ENTRIES must match this */ 
-       /* This should be a multiple of the cache line size */
-       /* GDTs of other CPUs are now dynamically allocated */
-
-       /* zero the remaining page */
-       .fill PAGE_SIZE / 8 - GDT_ENTRIES,8,0
-#endif
+NEXT_PAGE(level2_kernel_pgt)
+       .fill   512,8,0
 
 NEXT_PAGE(empty_zero_page)
-
-NEXT_PAGE(level3_physmem_pgt)
-       .quad   phys_level2_kernel_pgt | 0x007  /* so that __va works even before pagetable_init */
+       .skip PAGE_SIZE
 
 NEXT_PAGE(hypercall_page)
-.if (phys_hypercall_page - 0x10a000)
-       /* cause compiler error if the hypercall_page is at a
-        * different address than expected. */
-       .quad   __adjust_hypercall_page_in_header
-.endif
        .fill   512,8,0
 
 #undef NEXT_PAGE
 
        .data
 
-#ifndef CONFIG_XEN
-#ifdef CONFIG_ACPI_SLEEP
-       .align PAGE_SIZE
-ENTRY(wakeup_level4_pgt)
-       .quad   phys_level3_ident_pgt | 0x007
-       .fill   255,8,0
-       .quad   phys_level3_physmem_pgt | 0x007
-       .fill   254,8,0
-       /* (2^48-(2*1024*1024*1024))/(2^39) = 511 */
-       .quad   phys_level3_kernel_pgt | 0x007
-#endif
-
-#ifndef CONFIG_HOTPLUG_CPU
-       __INITDATA
-#endif
-       /*
-        * This default setting generates an ident mapping at address 0x100000
-        * and a mapping for the kernel that precisely maps virtual address
-        * 0xffffffff80000000 to physical address 0x000000. (always using
-        * 2Mbyte large pages provided by PAE mode)
-        */
-       .align PAGE_SIZE
-ENTRY(boot_level4_pgt)
-       .quad   phys_level3_ident_pgt | 0x007
-       .fill   255,8,0
-       .quad   phys_level3_physmem_pgt | 0x007
-       .fill   254,8,0
-       /* (2^48-(2*1024*1024*1024))/(2^39) = 511 */
-       .quad   phys_level3_kernel_pgt | 0x007
-#endif
-
-       .data
-
        .align 16
        .globl cpu_gdt_descr
 cpu_gdt_descr:
@@ -246,11 +102,59 @@ gdt:
  * Also sysret mandates a special GDT layout 
  */
                                
-.align PAGE_SIZE
+       .section .data.page_aligned, "aw"
+       .align PAGE_SIZE
 
+/* The TLS descriptors are currently at a different place compared to i386.
+   Hopefully nobody expects them at a fixed place (Wine?) */
+
+ENTRY(cpu_gdt_table)
+       .quad   0x0000000000000000      /* NULL descriptor */
+       .quad   0x0                     /* unused */
+       .quad   0x00affa000000ffff      /* __KERNEL_CS */
+       .quad   0x00cff2000000ffff      /* __KERNEL_DS */
+       .quad   0x00cffa000000ffff      /* __USER32_CS */
+       .quad   0x00cff2000000ffff      /* __USER_DS, __USER32_DS  */
+       .quad   0x00affa000000ffff      /* __USER_CS */
+       .quad   0x00cffa000000ffff      /* __KERNEL32_CS */
+       .quad   0,0                     /* TSS */
+       .quad   0,0                     /* LDT */
+       .quad   0,0,0                   /* three TLS descriptors */
+       .quad   0                       /* unused */
+gdt_end:
+       /* asm/segment.h:GDT_ENTRIES must match this */
+       /* This should be a multiple of the cache line size */
+       /* GDTs of other CPUs are now dynamically allocated */
+
+       /* zero the remaining page */
+       .fill PAGE_SIZE / 8 - GDT_ENTRIES,8,0
+
+       .section .bss, "aw", @nobits
+       .align L1_CACHE_BYTES
 ENTRY(idt_table)       
        .rept   256
        .quad   0
        .quad   0
        .endr
 
+/*
+ * __xen_guest information
+ */
+.macro utoh value
+ .if (\value) < 0 || (\value) >= 0x10
+       utoh (((\value)>>4)&0x0fffffffffffffff)
+ .endif
+ .if ((\value) & 0xf) < 10
+  .byte '0' + ((\value) & 0xf)
+ .else
+  .byte 'A' + ((\value) & 0xf) - 10
+ .endif
+.endm
+
+.section __xen_guest
+       .ascii  "GUEST_OS=linux,GUEST_VER=2.6"
+       .ascii  ",XEN_VER=xen-3.0"
+       .ascii  ",VIRT_BASE=0x"; utoh __START_KERNEL_map
+       .ascii  ",HYPERCALL_PAGE=0x"; utoh (phys_hypercall_page >> PAGE_SHIFT)
+       .ascii  ",LOADER=generic"
+       .byte   0

diff --git a/linux-2.6-xen-sparse/arch/x86_64/kernel/head64-xen.c b/linux-2.6-xen-sparse/arch/x86_64/kernel/head64-xen.c
index 82f0e9d89993c38d6f788f5295d95ee06d3e9ede..77176d0a321af269d55e842f02ba0980e0f4881e 100644 (file)
--- a/linux-2.6-xen-sparse/arch/x86_64/kernel/head64-xen.c
+++ b/linux-2.6-xen-sparse/arch/x86_64/kernel/head64-xen.c
@@ -47,7 +47,7 @@ extern char saved_command_line[];
 
 static void __init copy_bootdata(char *real_mode_data)
 {
-#if 0
+#ifndef CONFIG_XEN
        int new_data;
        char * command_line;
 
@@ -63,7 +63,6 @@ static void __init copy_bootdata(char *real_mode_data)
        }
        command_line = (char *) ((u64)(new_data));
        memcpy(saved_command_line, command_line, COMMAND_LINE_SIZE);
-       printk("Bootdata ok (command line is %s)\n", saved_command_line);
 #else
        int max_cmdline;
        
@@ -71,8 +70,8 @@ static void __init copy_bootdata(char *real_mode_data)
                max_cmdline = COMMAND_LINE_SIZE;
        memcpy(saved_command_line, xen_start_info->cmd_line, max_cmdline);
        saved_command_line[max_cmdline-1] = '\0';
-       printk("Bootdata ok (command line is %s)\n", saved_command_line);
 #endif
+       printk("Bootdata ok (command line is %s)\n", saved_command_line);
 }
 
 static void __init setup_boot_cpu_data(void)
@@ -98,6 +97,7 @@ void __init x86_64_start_kernel(char * real_mode_data)
        char *s;
        int i;
 
+       xen_start_info = (struct start_info *)real_mode_data;
        if (!xen_feature(XENFEAT_auto_translated_physmap)) {
                phys_to_machine_mapping =
                        (unsigned long *)xen_start_info->mfn_list;
@@ -105,9 +105,9 @@ void __init x86_64_start_kernel(char * real_mode_data)
                        xen_start_info->nr_pt_frames;
        }
 
+#if 0
        for (i = 0; i < 256; i++)
                set_intr_gate(i, early_idt_handler);
-#if 0
        asm volatile("lidt %0" :: "m" (idt_descr));
 #endif