x86, realmode: Move SMP trampoline to unified realmode code

Migrated SMP trampoline code to the real mode blob.
SMP trampoline code is not yet removed from
.x86_trampoline because it is needed by the wakeup
code.

[ hpa: always enable compiling startup_32_smp in head_32.S... it is
  only a few instructions which go into .init on UP builds, and it makes
  the rest of the code less #ifdef ugly. ]

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@intel.com>
Link: http://lkml.kernel.org/r/1336501366-28617-6-git-send-email-jarkko.sakkinen@intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

9 files changed, 316 insertions, 16 deletions

diff --git a/arch/x86/include/asm/realmode.h b/arch/x86/include/asm/realmode.h
index bf26b0681931..9b4a5da5e22e 100644
--- a/arch/x86/include/asm/realmode.h
+++ b/arch/x86/include/asm/realmode.h
@@ -13,6 +13,17 @@ struct real_mode_header {
 #ifdef CONFIG_X86_32
         u32     machine_real_restart_asm;
 #endif
+        /* SMP trampoline */
+        u32     trampoline_data;
+        u32     trampoline_status;
+#ifdef CONFIG_X86_32
+        u32     startup_32_smp;
+        u32     boot_gdt;
+#else
+        u32     startup_64_smp;
+        u32     level3_ident_pgt;
+        u32     level3_kernel_pgt;
+#endif
 } __attribute__((__packed__));
 
 extern struct real_mode_header real_mode_header;
@@ -25,6 +36,13 @@ extern unsigned long initial_gs;
 extern unsigned char real_mode_blob[];
 extern unsigned char real_mode_relocs[];
 
+#ifdef CONFIG_X86_32
+extern unsigned char startup_32_smp[];
+extern unsigned char boot_gdt[];
+#else
+extern unsigned char secondary_startup_64[];
+#endif
+
 extern void __init setup_real_mode(void);
 
 #endif /* _ARCH_X86_REALMODE_H */
diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S
index ce0be7cd085e..a3c2b4ffebc6 100644
--- a/arch/x86/kernel/head_32.S
+++ b/arch/x86/kernel/head_32.S
@@ -273,10 +273,7 @@ num_subarch_entries = (. - subarch_entries) / 4
  * If cpu hotplug is not supported then this code can go in init section
  * which will be freed later
  */
-
 __CPUINIT
-
-#ifdef CONFIG_SMP
 ENTRY(startup_32_smp)
         cld
         movl $(__BOOT_DS),%eax
@@ -287,7 +284,7 @@ ENTRY(startup_32_smp)
         movl pa(stack_start),%ecx
         movl %eax,%ss
         leal -__PAGE_OFFSET(%ecx),%esp
-#endif /* CONFIG_SMP */
+
 default_entry:
 
 /*
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index 40f4eb3766d1..d70bc2eb202b 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -136,10 +136,6 @@ ident_complete:
         /* Fixup phys_base */
         addq    %rbp, phys_base(%rip)
 
-        /* Fixup trampoline */
-        addq    %rbp, trampoline_level4_pgt + 0(%rip)
-        addq    %rbp, trampoline_level4_pgt + (511*8)(%rip)
-
         /* Due to ENTRY(), sometimes the empty space gets filled with
          * zeros. Better take a jmp than relying on empty space being
          * filled with 0x90 (nop)
diff --git a/arch/x86/kernel/realmode.c b/arch/x86/kernel/realmode.c
index 7415c42547ac..a465775b32f2 100644
--- a/arch/x86/kernel/realmode.c
+++ b/arch/x86/kernel/realmode.c
@@ -58,6 +58,20 @@ void __init setup_real_mode(void)
         /* Copied header will contain relocated physical addresses. */
         memcpy(&real_mode_header, real_mode_base,
                sizeof(struct real_mode_header));
+
+#ifdef CONFIG_X86_32
+        *((u32 *)__va(real_mode_header.startup_32_smp)) = __pa(startup_32_smp);
+        *((u32 *)__va(real_mode_header.boot_gdt)) = __pa(boot_gdt);
+#else
+        *((u64 *) __va(real_mode_header.startup_64_smp)) =
+                (u64) __pa(secondary_startup_64);
+
+        *((u64 *) __va(real_mode_header.level3_ident_pgt)) =
+                __pa(level3_ident_pgt) + _KERNPG_TABLE;
+
+        *((u64 *) __va(real_mode_header.level3_kernel_pgt)) =
+                __pa(level3_kernel_pgt) + _KERNPG_TABLE;
+#endif
 }
 
 /*
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 6e1e406038c2..c7971ea74bd0 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -57,7 +57,7 @@
 #include <asm/nmi.h>
 #include <asm/irq.h>
 #include <asm/idle.h>
-#include <asm/trampoline.h>
+#include <asm/realmode.h>
 #include <asm/cpu.h>
 #include <asm/numa.h>
 #include <asm/pgtable.h>
@@ -73,6 +73,8 @@
 #include <asm/smpboot_hooks.h>
 #include <asm/i8259.h>
 
+#include <asm/realmode.h>
+
 /* State of each CPU */
 DEFINE_PER_CPU(int, cpu_state) = { 0 };
 
@@ -662,8 +664,12 @@ static void __cpuinit announce_cpu(int cpu, int apicid)
  */
 static int __cpuinit do_boot_cpu(int apicid, int cpu)
 {
+        volatile u32 *trampoline_status =
+                (volatile u32 *) __va(real_mode_header.trampoline_status);
+        /* start_ip had better be page-aligned! */
+        unsigned long start_ip = real_mode_header.trampoline_data;
+
         unsigned long boot_error = 0;
-        unsigned long start_ip;
         int timeout;
         struct create_idle c_idle = {
                 .cpu    = cpu,
@@ -713,9 +719,6 @@ do_rest:
         initial_code = (unsigned long)start_secondary;
         stack_start  = c_idle.idle->thread.sp;
 
-        /* start_ip had better be page-aligned! */
-        start_ip = trampoline_address();
-
         /* So we see what's up */
         announce_cpu(cpu, apicid);
 
@@ -778,8 +781,7 @@ do_rest:
                         pr_debug("CPU%d: has booted.\n", cpu);
                 } else {
                         boot_error = 1;
-                        if (*(volatile u32 *)TRAMPOLINE_SYM(trampoline_status)
-                            == 0xA5A5A5A5)
+                        if (*trampoline_status == 0xA5A5A5A5)
                                 /* trampoline started but...? */
                                 pr_err("CPU%d: Stuck ??\n", cpu);
                         else
@@ -805,7 +807,7 @@ do_rest:
         }
 
         /* mark "stuck" area as not stuck */
-        *(volatile u32 *)TRAMPOLINE_SYM(trampoline_status) = 0;
+        *trampoline_status = 0;
 
         if (get_uv_system_type() != UV_NON_UNIQUE_APIC) {
                 /*
diff --git a/arch/x86/realmode/rm/Makefile b/arch/x86/realmode/rm/Makefile
index 3f851c488593..56ec64f94e69 100644
--- a/arch/x86/realmode/rm/Makefile
+++ b/arch/x86/realmode/rm/Makefile
@@ -13,6 +13,7 @@ always := realmode.bin
 
 realmode-y                      += header.o
 realmode-$(CONFIG_X86_32)       += reboot_32.o
+realmode-y                      += trampoline_$(BITS).o
 
 targets += $(realmode-y)
 
diff --git a/arch/x86/realmode/rm/header.S b/arch/x86/realmode/rm/header.S
index db21401c0c57..a97900409c61 100644
--- a/arch/x86/realmode/rm/header.S
+++ b/arch/x86/realmode/rm/header.S
@@ -16,4 +16,15 @@ ENTRY(real_mode_header)
 #ifdef CONFIG_X86_32
                 .long   pa_machine_real_restart_asm
 #endif
+                /* SMP trampoline */
+                .long   pa_trampoline_data
+                .long   pa_trampoline_status
+#ifdef CONFIG_X86_32
+                .long   pa_startup_32_smp
+                .long   pa_boot_gdt
+#else
+                .long   pa_startup_64_smp
+                .long   pa_level3_ident_pgt
+                .long   pa_level3_kernel_pgt
+#endif
 END(real_mode_header)
diff --git a/arch/x86/realmode/rm/trampoline_32.S b/arch/x86/realmode/rm/trampoline_32.S
new file mode 100644
index 000000000000..18cb7fc9fad4
--- /dev/null
+++ b/arch/x86/realmode/rm/trampoline_32.S
@@ -0,0 +1,86 @@
+/*
+ *
+ *      Trampoline.S    Derived from Setup.S by Linus Torvalds
+ *
+ *      4 Jan 1997 Michael Chastain: changed to gnu as.
+ *
+ *      This is only used for booting secondary CPUs in SMP machine
+ *
+ *      Entry: CS:IP point to the start of our code, we are
+ *      in real mode with no stack, but the rest of the
+ *      trampoline page to make our stack and everything else
+ *      is a mystery.
+ *
+ *      We jump into arch/x86/kernel/head_32.S.
+ *
+ *      On entry to trampoline_data, the processor is in real mode
+ *      with 16-bit addressing and 16-bit data.  CS has some value
+ *      and IP is zero.  Thus, we load CS to the physical segment
+ *      of the real mode code before doing anything further.
+ *
+ *      The structure real_mode_header includes entries that need
+ *      to be set up before executing this code:
+ *
+ *      startup_32_smp
+ *      boot_gdt
+ */
+
+#include <linux/linkage.h>
+#include <linux/init.h>
+#include <asm/segment.h>
+#include <asm/page_types.h>
+
+        .text
+        .code16
+        .globl trampoline_data
+
+        .balign PAGE_SIZE
+trampoline_data:
+        wbinvd                  # Needed for NUMA-Q should be harmless for others
+
+        .byte   0xea            # ljmpw
+        .word   1f              # Offset
+        .word   real_mode_seg   # Segment
+1:
+        mov     %cs, %ax        # Code and data in the same place
+        mov     %ax, %ds
+
+        cli                     # We should be safe anyway
+
+        movl    $0xA5A5A5A5, trampoline_status
+                                # write marker for master knows we're running
+
+        /* GDT tables in non default location kernel can be beyond 16MB and
+         * lgdt will not be able to load the address as in real mode default
+         * operand size is 16bit. Use lgdtl instead to force operand size
+         * to 32 bit.
+         */
+
+        lidtl   boot_idt_descr          # load idt with 0, 0
+        lgdtl   boot_gdt_descr          # load gdt with whatever is appropriate
+
+        xor     %ax, %ax
+        inc     %ax                     # protected mode (PE) bit
+        lmsw    %ax                     # into protected mode
+
+        # flush prefetch and jump to startup_32_smp in arch/i386/kernel/head.S
+        ljmpl   *(startup_32_smp)
+
+        .data
+        .globl startup_32_smp, boot_gdt, trampoline_status
+
+boot_gdt_descr:
+        .word   __BOOT_DS + 7                   # gdt limit
+boot_gdt:
+        .long   0                               # gdt base
+
+boot_idt_descr:
+        .word   0                               # idt limit = 0
+        .long   0                               # idt base = 0L
+
+trampoline_status:
+        .long   0
+
+startup_32_smp:
+        .long   0x00000000
+        .word   __BOOT_CS, 0
diff --git a/arch/x86/realmode/rm/trampoline_64.S b/arch/x86/realmode/rm/trampoline_64.S
new file mode 100644
index 000000000000..063da008d520
--- /dev/null
+++ b/arch/x86/realmode/rm/trampoline_64.S
@@ -0,0 +1,175 @@
+/*
+ *
+ *      Trampoline.S    Derived from Setup.S by Linus Torvalds
+ *
+ *      4 Jan 1997 Michael Chastain: changed to gnu as.
+ *      15 Sept 2005 Eric Biederman: 64bit PIC support
+ *
+ *      Entry: CS:IP point to the start of our code, we are
+ *      in real mode with no stack, but the rest of the
+ *      trampoline page to make our stack and everything else
+ *      is a mystery.
+ *
+ *      On entry to trampoline_data, the processor is in real mode
+ *      with 16-bit addressing and 16-bit data.  CS has some value
+ *      and IP is zero.  Thus, data addresses need to be absolute
+ *      (no relocation) and are taken with regard to r_base.
+ *
+ *      With the addition of trampoline_level4_pgt this code can
+ *      now enter a 64bit kernel that lives at arbitrary 64bit
+ *      physical addresses.
+ *
+ *      If you work on this file, check the object module with objdump
+ *      --full-contents --reloc to make sure there are no relocation
+ *      entries.
+ */
+
+#include <linux/linkage.h>
+#include <linux/init.h>
+#include <asm/pgtable_types.h>
+#include <asm/page_types.h>
+#include <asm/msr.h>
+#include <asm/segment.h>
+#include <asm/processor-flags.h>
+
+        .text
+        .balign PAGE_SIZE
+        .code16
+
+ENTRY(trampoline_data)
+        cli                     # We should be safe anyway
+        wbinvd
+
+        .byte   0xea            # ljmpw
+        .word   1f              # Offset
+        .word   real_mode_seg   # Segment
+1:
+        mov     %cs, %ax        # Code and data in the same place
+        mov     %ax, %ds
+        mov     %ax, %es
+        mov     %ax, %ss
+
+        movl    $0xA5A5A5A5, trampoline_status
+        # write marker for master knows we're running
+
+        # Setup stack
+        movw    $trampoline_stack_end, %sp
+
+        call    verify_cpu              # Verify the cpu supports long mode
+        testl   %eax, %eax              # Check for return code
+        jnz     no_longmode
+
+        /*
+         * GDT tables in non default location kernel can be beyond 16MB and
+         * lgdt will not be able to load the address as in real mode default
+         * operand size is 16bit. Use lgdtl instead to force operand size
+         * to 32 bit.
+         */
+
+        lidtl   tidt    # load idt with 0, 0
+        lgdtl   tgdt    # load gdt with whatever is appropriate
+
+        mov     $X86_CR0_PE, %ax        # protected mode (PE) bit
+        lmsw    %ax                     # into protected mode
+
+        # flush prefetch and jump to startup_32
+        ljmpl   *(startup_32_vector)
+
+no_longmode:
+        hlt
+        jmp no_longmode
+#include "../kernel/verify_cpu.S"
+
+        .code32
+        .balign 4
+ENTRY(startup_32)
+        movl    $__KERNEL_DS, %eax      # Initialize the %ds segment register
+        movl    %eax, %ds
+
+        movl    $X86_CR4_PAE, %eax
+        movl    %eax, %cr4              # Enable PAE mode
+
+        movl    pa_startup_64_smp, %esi
+        movl    pa_startup_64_smp_high, %edi
+
+                                        # Setup trampoline 4 level pagetables
+        leal    pa_trampoline_level4_pgt, %eax
+        movl    %eax, %cr3
+
+        movl    $MSR_EFER, %ecx
+        movl    $(1 << _EFER_LME), %eax # Enable Long Mode
+        xorl    %edx, %edx
+        wrmsr
+
+        # Enable paging and in turn activate Long Mode
+        # Enable protected mode
+        movl    $(X86_CR0_PG | X86_CR0_PE), %eax
+        movl    %eax, %cr0
+
+        /*
+         * At this point we're in long mode but in 32bit compatibility mode
+         * with EFER.LME = 1, CS.L = 0, CS.D = 1 (and in turn
+         * EFER.LMA = 1). Now we want to jump in 64bit mode, to do that we use
+         * the new gdt/idt that has __KERNEL_CS with CS.L = 1.
+         */
+        ljmpl   *(pa_startup_64_vector)
+
+        .code64
+        .balign 4
+ENTRY(startup_64)
+        # Now jump into the kernel using virtual addresses
+        movl    %edi, %eax
+        shlq    $32, %rax
+        addl    %esi, %eax
+        jmp     *%rax
+
+        # Careful these need to be in the same 64K segment as the above;
+tidt:
+        .word   0                       # idt limit = 0
+        .word   0, 0                    # idt base = 0L
+
+        # Duplicate the global descriptor table
+        # so the kernel can live anywhere
+        .balign 4
+        .globl tgdt
+tgdt:
+        .short  tgdt_end - tgdt         # gdt limit
+        .long   pa_tgdt
+        .short  0
+        .quad   0x00cf9b000000ffff      # __KERNEL32_CS
+        .quad   0x00af9b000000ffff      # __KERNEL_CS
+        .quad   0x00cf93000000ffff      # __KERNEL_DS
+tgdt_end:
+
+        .balign 4
+startup_32_vector:
+        .long   pa_startup_32
+        .word   __KERNEL32_CS, 0
+
+        .balign 4
+        .globl startup_64_vector
+startup_64_vector:
+        .long   pa_startup_64
+        .word   __KERNEL_CS, 0
+
+        .data
+
+        .balign 4
+ENTRY(trampoline_status)
+        .long   0
+
+trampoline_stack:
+        .org 0x1000
+trampoline_stack_end:
+
+        .globl  level3_ident_pgt
+        .globl  level3_kernel_pgt
+ENTRY(trampoline_level4_pgt)
+        level3_ident_pgt:       .quad   0
+        .fill 510,8,0
+        level3_kernel_pgt:      .quad   0
+
+        .globl  startup_64_smp
+        .globl  startup_64_smp_high
+startup_64_smp:         .long 0
+startup_64_smp_high:    .long 0