[PATCH] x86-64: do not use virt_to_page on kernel data address

o virt_to_page() call should be used on kernel linear addresses and not
  on kernel text and data addresses. Swsusp code uses it on kernel data
  (statically allocated swsusp_header).

o Allocate swsusp_header dynamically so that virt_to_page() can be used
  safely.

o I am changing this because in next few patches, __pa() on x86_64 will
  no longer support kernel text and data addresses and hibernation breaks.

Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Andi Kleen <ak@suse.de>

1 files changed, 27 insertions, 15 deletions

diff --git a/kernel/power/swap.c b/kernel/power/swap.c
index 3581f8f86ac..b18c155cbb6 100644
--- a/kernel/power/swap.c
+++ b/kernel/power/swap.c
@@ -33,12 +33,14 @@ extern char resume_file[];
 
 #define SWSUSP_SIG      "S1SUSPEND"
 
-static struct swsusp_header {
+struct swsusp_header {
         char reserved[PAGE_SIZE - 20 - sizeof(sector_t)];
         sector_t image;
         char    orig_sig[10];
         char    sig[10];
-} __attribute__((packed, aligned(PAGE_SIZE))) swsusp_header;
+} __attribute__((packed));
+
+static struct swsusp_header *swsusp_header;
 
 /*
  * General things
@@ -141,14 +143,14 @@ static int mark_swapfiles(sector_t start)
 {
         int error;
 
-        bio_read_page(swsusp_resume_block, &swsusp_header, NULL);
-        if (!memcmp("SWAP-SPACE",swsusp_header.sig, 10) ||
-            !memcmp("SWAPSPACE2",swsusp_header.sig, 10)) {
-                memcpy(swsusp_header.orig_sig,swsusp_header.sig, 10);
-                memcpy(swsusp_header.sig,SWSUSP_SIG, 10);
-                swsusp_header.image = start;
+        bio_read_page(swsusp_resume_block, swsusp_header, NULL);
+        if (!memcmp("SWAP-SPACE",swsusp_header->sig, 10) ||
+            !memcmp("SWAPSPACE2",swsusp_header->sig, 10)) {
+                memcpy(swsusp_header->orig_sig,swsusp_header->sig, 10);
+                memcpy(swsusp_header->sig,SWSUSP_SIG, 10);
+                swsusp_header->image = start;
                 error = bio_write_page(swsusp_resume_block,
-                                        &swsusp_header, NULL);
+                                        swsusp_header, NULL);
         } else {
                 printk(KERN_ERR "swsusp: Swap header not found!\n");
                 error = -ENODEV;
@@ -564,7 +566,7 @@ int swsusp_read(void)
         if (error < PAGE_SIZE)
                 return error < 0 ? error : -EFAULT;
         header = (struct swsusp_info *)data_of(snapshot);
-        error = get_swap_reader(&handle, swsusp_header.image);
+        error = get_swap_reader(&handle, swsusp_header->image);
         if (!error)
                 error = swap_read_page(&handle, header, NULL);
         if (!error)
@@ -591,17 +593,17 @@ int swsusp_check(void)
         resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_READ);
         if (!IS_ERR(resume_bdev)) {
                 set_blocksize(resume_bdev, PAGE_SIZE);
-                memset(&swsusp_header, 0, sizeof(swsusp_header));
+                memset(swsusp_header, 0, sizeof(PAGE_SIZE));
                 error = bio_read_page(swsusp_resume_block,
-                                        &swsusp_header, NULL);
+                                        swsusp_header, NULL);
                 if (error)
                         return error;
 
-                if (!memcmp(SWSUSP_SIG, swsusp_header.sig, 10)) {
-                        memcpy(swsusp_header.sig, swsusp_header.orig_sig, 10);
+                if (!memcmp(SWSUSP_SIG, swsusp_header->sig, 10)) {
+                        memcpy(swsusp_header->sig, swsusp_header->orig_sig, 10);
                         /* Reset swap signature now */
                         error = bio_write_page(swsusp_resume_block,
-                                                &swsusp_header, NULL);
+                                                swsusp_header, NULL);
                 } else {
                         return -EINVAL;
                 }
@@ -632,3 +634,13 @@ void swsusp_close(void)
 
         blkdev_put(resume_bdev);
 }
+
+static int swsusp_header_init(void)
+{
+        swsusp_header = (struct swsusp_header*) __get_free_page(GFP_KERNEL);
+        if (!swsusp_header)
+                panic("Could not allocate memory for swsusp_header\n");
+        return 0;
+}
+
+core_initcall(swsusp_header_init);