x86, kexec: x86_64: add kexec jump support for x86_64

Impact: New major feature

This patch add kexec jump support for x86_64. More information about
kexec jump can be found in corresponding x86_32 support patch.

Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

3 files changed, 189 insertions, 37 deletions

diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
index 7cc5d3d01483..89cea4d44679 100644
--- a/arch/x86/kernel/machine_kexec_64.c
+++ b/arch/x86/kernel/machine_kexec_64.c
@@ -13,6 +13,7 @@
 #include <linux/numa.h>
 #include <linux/ftrace.h>
 #include <linux/io.h>
+#include <linux/suspend.h>
 
 #include <asm/pgtable.h>
 #include <asm/tlbflush.h>
@@ -270,19 +271,43 @@ void machine_kexec(struct kimage *image)
 {
         unsigned long page_list[PAGES_NR];
         void *control_page;
+        int save_ftrace_enabled;
 
-        tracer_disable();
+#ifdef CONFIG_KEXEC_JUMP
+        if (kexec_image->preserve_context)
+                save_processor_state();
+#endif
+
+        save_ftrace_enabled = __ftrace_enabled_save();
 
         /* Interrupts aren't acceptable while we reboot */
         local_irq_disable();
 
+        if (image->preserve_context) {
+#ifdef CONFIG_X86_IO_APIC
+                /*
+                 * We need to put APICs in legacy mode so that we can
+                 * get timer interrupts in second kernel. kexec/kdump
+                 * paths already have calls to disable_IO_APIC() in
+                 * one form or other. kexec jump path also need
+                 * one.
+                 */
+                disable_IO_APIC();
+#endif
+        }
+
         control_page = page_address(image->control_code_page) + PAGE_SIZE;
-        memcpy(control_page, relocate_kernel, PAGE_SIZE);
+        memcpy(control_page, relocate_kernel, KEXEC_CONTROL_CODE_MAX_SIZE);
 
         page_list[PA_CONTROL_PAGE] = virt_to_phys(control_page);
+        page_list[VA_CONTROL_PAGE] = (unsigned long)control_page;
         page_list[PA_TABLE_PAGE] =
           (unsigned long)__pa(page_address(image->control_code_page));
 
+        if (image->type == KEXEC_TYPE_DEFAULT)
+                page_list[PA_SWAP_PAGE] = (page_to_pfn(image->swap_page)
+                                                << PAGE_SHIFT);
+
         /*
          * The segment registers are funny things, they have both a
          * visible and an invisible part.  Whenever the visible part is
@@ -302,8 +327,17 @@ void machine_kexec(struct kimage *image)
         set_idt(phys_to_virt(0), 0);
 
         /* now call it */
-        relocate_kernel((unsigned long)image->head, (unsigned long)page_list,
-                        image->start);
+        image->start = relocate_kernel((unsigned long)image->head,
+                                       (unsigned long)page_list,
+                                       image->start,
+                                       image->preserve_context);
+
+#ifdef CONFIG_KEXEC_JUMP
+        if (kexec_image->preserve_context)
+                restore_processor_state();
+#endif
+
+        __ftrace_enabled_restore(save_ftrace_enabled);
 }
 
 void arch_crash_save_vmcoreinfo(void)
diff --git a/arch/x86/kernel/relocate_kernel_64.S b/arch/x86/kernel/relocate_kernel_64.S
index cfc0d24003dc..4de8f5b3d476 100644
--- a/arch/x86/kernel/relocate_kernel_64.S
+++ b/arch/x86/kernel/relocate_kernel_64.S
@@ -19,6 +19,24 @@
 #define PTR(x) (x << 3)
 #define PAGE_ATTR (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | _PAGE_DIRTY)
 
+/*
+ * control_page + KEXEC_CONTROL_CODE_MAX_SIZE
+ * ~ control_page + PAGE_SIZE are used as data storage and stack for
+ * jumping back
+ */
+#define DATA(offset)            (KEXEC_CONTROL_CODE_MAX_SIZE+(offset))
+
+/* Minimal CPU state */
+#define RSP                     DATA(0x0)
+#define CR0                     DATA(0x8)
+#define CR3                     DATA(0x10)
+#define CR4                     DATA(0x18)
+
+/* other data */
+#define CP_PA_TABLE_PAGE        DATA(0x20)
+#define CP_PA_SWAP_PAGE         DATA(0x28)
+#define CP_PA_BACKUP_PAGES_MAP  DATA(0x30)
+
         .text
         .align PAGE_SIZE
         .code64
@@ -28,8 +46,27 @@ relocate_kernel:
          * %rdi indirection_page
          * %rsi page_list
          * %rdx start address
+         * %rcx preserve_context
          */
 
+        /* Save the CPU context, used for jumping back */
+        pushq %rbx
+        pushq %rbp
+        pushq %r12
+        pushq %r13
+        pushq %r14
+        pushq %r15
+        pushf
+
+        movq    PTR(VA_CONTROL_PAGE)(%rsi), %r11
+        movq    %rsp, RSP(%r11)
+        movq    %cr0, %rax
+        movq    %rax, CR0(%r11)
+        movq    %cr3, %rax
+        movq    %rax, CR3(%r11)
+        movq    %cr4, %rax
+        movq    %rax, CR4(%r11)
+
         /* zero out flags, and disable interrupts */
         pushq $0
         popfq
@@ -41,10 +78,18 @@ relocate_kernel:
         movq    PTR(PA_CONTROL_PAGE)(%rsi), %r8
 
         /* get physical address of page table now too */
-        movq    PTR(PA_TABLE_PAGE)(%rsi), %rcx
+        movq    PTR(PA_TABLE_PAGE)(%rsi), %r9
+
+        /* get physical address of swap page now */
+        movq    PTR(PA_SWAP_PAGE)(%rsi), %r10
+
+        /* save some information for jumping back */
+        movq    %r9, CP_PA_TABLE_PAGE(%r11)
+        movq    %r10, CP_PA_SWAP_PAGE(%r11)
+        movq    %rdi, CP_PA_BACKUP_PAGES_MAP(%r11)
 
         /* Switch to the identity mapped page tables */
-        movq    %rcx, %cr3
+        movq    %r9, %cr3
 
         /* setup a new stack at the end of the physical control page */
         lea     PAGE_SIZE(%r8), %rsp
@@ -83,9 +128,87 @@ identity_mapped:
 1:
 
         /* Flush the TLB (needed?) */
-        movq    %rcx, %cr3
+        movq    %r9, %cr3
+
+        movq    %rcx, %r11
+        call    swap_pages
+
+        /*
+         * To be certain of avoiding problems with self-modifying code
+         * I need to execute a serializing instruction here.
+         * So I flush the TLB by reloading %cr3 here, it's handy,
+         * and not processor dependent.
+         */
+        movq    %cr3, %rax
+        movq    %rax, %cr3
+
+        /*
+         * set all of the registers to known values
+         * leave %rsp alone
+         */
+
+        testq   %r11, %r11
+        jnz 1f
+        xorq    %rax, %rax
+        xorq    %rbx, %rbx
+        xorq    %rcx, %rcx
+        xorq    %rdx, %rdx
+        xorq    %rsi, %rsi
+        xorq    %rdi, %rdi
+        xorq    %rbp, %rbp
+        xorq    %r8,  %r8
+        xorq    %r9,  %r9
+        xorq    %r10, %r9
+        xorq    %r11, %r11
+        xorq    %r12, %r12
+        xorq    %r13, %r13
+        xorq    %r14, %r14
+        xorq    %r15, %r15
+
+        ret
+
+1:
+        popq    %rdx
+        leaq    PAGE_SIZE(%r10), %rsp
+        call    *%rdx
+
+        /* get the re-entry point of the peer system */
+        movq    0(%rsp), %rbp
+        call    1f
+1:
+        popq    %r8
+        subq    $(1b - relocate_kernel), %r8
+        movq    CP_PA_SWAP_PAGE(%r8), %r10
+        movq    CP_PA_BACKUP_PAGES_MAP(%r8), %rdi
+        movq    CP_PA_TABLE_PAGE(%r8), %rax
+        movq    %rax, %cr3
+        lea     PAGE_SIZE(%r8), %rsp
+        call    swap_pages
+        movq    $virtual_mapped, %rax
+        pushq   %rax
+        ret
+
+virtual_mapped:
+        movq    RSP(%r8), %rsp
+        movq    CR4(%r8), %rax
+        movq    %rax, %cr4
+        movq    CR3(%r8), %rax
+        movq    CR0(%r8), %r8
+        movq    %rax, %cr3
+        movq    %r8, %cr0
+        movq    %rbp, %rax
+
+        popf
+        popq    %r15
+        popq    %r14
+        popq    %r13
+        popq    %r12
+        popq    %rbp
+        popq    %rbx
+        ret
 
         /* Do the copies */
+swap_pages:
         movq    %rdi, %rcx      /* Put the page_list in %rcx */
         xorq    %rdi, %rdi
         xorq    %rsi, %rsi
@@ -117,39 +240,27 @@ identity_mapped:
         movq    %rcx,   %rsi  /* For ever source page do a copy */
         andq    $0xfffffffffffff000, %rsi
 
+        movq    %rdi, %rdx
+        movq    %rsi, %rax
+
+        movq    %r10, %rdi
         movq    $512,   %rcx
         rep ; movsq
-        jmp     0b
-3:
 
-        /*
-         * To be certain of avoiding problems with self-modifying code
-         * I need to execute a serializing instruction here.
-         * So I flush the TLB by reloading %cr3 here, it's handy,
-         * and not processor dependent.
-         */
-        movq    %cr3, %rax
-        movq    %rax, %cr3
-
-        /*
-         * set all of the registers to known values
-         * leave %rsp alone
-         */
+        movq    %rax, %rdi
+        movq    %rdx, %rsi
+        movq    $512,   %rcx
+        rep ; movsq
 
-        xorq    %rax, %rax
-        xorq    %rbx, %rbx
-        xorq    %rcx, %rcx
-        xorq    %rdx, %rdx
-        xorq    %rsi, %rsi
-        xorq    %rdi, %rdi
-        xorq    %rbp, %rbp
-        xorq    %r8,  %r8
-        xorq    %r9,  %r9
-        xorq    %r10, %r9
-        xorq    %r11, %r11
-        xorq    %r12, %r12
-        xorq    %r13, %r13
-        xorq    %r14, %r14
-        xorq    %r15, %r15
+        movq    %rdx, %rdi
+        movq    %r10, %rsi
+        movq    $512,   %rcx
+        rep ; movsq
 
+        lea     PAGE_SIZE(%rax), %rsi
+        jmp     0b
+3:
         ret
+
+        .globl kexec_control_code_size
+.set kexec_control_code_size, . - relocate_kernel
diff --git a/arch/x86/kernel/vmlinux_64.lds.S b/arch/x86/kernel/vmlinux_64.lds.S
index fbfced6f6800..5bf54e40c6ef 100644
--- a/arch/x86/kernel/vmlinux_64.lds.S
+++ b/arch/x86/kernel/vmlinux_64.lds.S
@@ -275,3 +275,10 @@ ASSERT((_end - _text <= KERNEL_IMAGE_SIZE),
 ASSERT((per_cpu__irq_stack_union == 0),
         "irq_stack_union is not at start of per-cpu area");
 #endif
+
+#ifdef CONFIG_KEXEC
+#include <asm/kexec.h>
+
+ASSERT(kexec_control_code_size <= KEXEC_CONTROL_CODE_MAX_SIZE,
+       "kexec control code size is too big")
+#endif