1 files changed, 34 insertions, 7 deletions

diff --git a/arch/x86/kernel/suspend_asm_64.S b/arch/x86/kernel/suspend_asm_64.S
index 16d183f67bc1..40a209e0525c 100644
--- a/arch/x86/kernel/suspend_asm_64.S
+++ b/arch/x86/kernel/suspend_asm_64.S
@@ -2,8 +2,8 @@
  *
  * Distribute under GPLv2.
  *
- * swsusp_arch_resume may not use any stack, nor any variable that is
- * not "NoSave" during copying pages:
+ * swsusp_arch_resume must not use any stack or any nonlocal variables while
+ * copying pages:
  *
  * Its rewriting one kernel image with another. What is stack in "old"
  * image could very well be data page in "new" image, and overwriting
@@ -36,6 +36,10 @@ ENTRY(swsusp_arch_suspend)
         movq %r15, saved_context_r15(%rip)
         pushfq ; popq saved_context_eflags(%rip)
 
+        /* save the address of restore_registers */
+        movq    $restore_registers, %rax
+        movq    %rax, restore_jump_address(%rip)
+
         call swsusp_save
         ret
 
@@ -54,7 +58,16 @@ ENTRY(restore_image)
         movq    %rcx, %cr3;
         movq    %rax, %cr4;  # turn PGE back on
 
+        /* prepare to jump to the image kernel */
+        movq    restore_jump_address(%rip), %rax
+
+        /* prepare to copy image data to their original locations */
         movq    restore_pblist(%rip), %rdx
+        movq    relocated_restore_code(%rip), %rcx
+        jmpq    *%rcx
+
+        /* code below has been relocated to a safe page */
+ENTRY(core_restore_code)
 loop:
         testq   %rdx, %rdx
         jz      done
@@ -62,7 +75,7 @@ loop:
         /* get addresses from the pbe and copy the page */
         movq    pbe_address(%rdx), %rsi
         movq    pbe_orig_address(%rdx), %rdi
-        movq    $512, %rcx
+        movq    $(PAGE_SIZE >> 3), %rcx
         rep
         movsq
 
@@ -70,6 +83,20 @@ loop:
         movq    pbe_next(%rdx), %rdx
         jmp     loop
 done:
+        /* jump to the restore_registers address from the image header */
+        jmpq    *%rax
+        /*
+         * NOTE: This assumes that the boot kernel's text mapping covers the
+         * image kernel's page containing restore_registers and the address of
+         * this page is the same as in the image kernel's text mapping (it
+         * should always be true, because the text mapping is linear, starting
+         * from 0, and is supposed to cover the entire kernel text for every
+         * kernel).
+         *
+         * code below belongs to the image kernel
+         */
+
+ENTRY(restore_registers)
         /* go back to the original page tables */
         movq    $(init_level4_pgt - __START_KERNEL_map), %rax
         addq    phys_base(%rip), %rax
@@ -84,12 +111,9 @@ done:
         movq    %rcx, %cr3
         movq    %rax, %cr4;  # turn PGE back on
 
-        movl    $24, %eax
-        movl    %eax, %ds
-
         movq saved_context_esp(%rip), %rsp
         movq saved_context_ebp(%rip), %rbp
-        /* Don't restore %rax, it must be 0 anyway */
+        /* restore GPRs (we don't restore %rax, it must be 0 anyway) */
         movq saved_context_ebx(%rip), %rbx
         movq saved_context_ecx(%rip), %rcx
         movq saved_context_edx(%rip), %rdx
@@ -107,4 +131,7 @@ done:
 
         xorq    %rax, %rax
 
+        /* tell the hibernation core that we've just restored the memory */
+        movq    %rax, in_suspend(%rip)
+
         ret