[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>

diff --git a/kernel/power/swap.c b/kernel/power/swap.c
index 3581f8f86acdc430d4fdd8edb09dfc8d31d2b5c0..b18c155cbb6003f44a343f2d76a91283931bc110 100644 (file)
--- 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);