kexec: support for kexec on panic using new system call

[linux.git] / kernel / kexec.c

diff --git a/kernel/kexec.c b/kernel/kexec.c
index 0926f2a3ed03122565339310ae540ae9f0a924b9..f18c780f971657eaee0580e195dfd2cc48184c90 100644 (file)
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -548,6 +548,7 @@ kimage_file_alloc_init(struct kimage **rimage, int kernel_fd,
 {
        int ret;
        struct kimage *image;
+       bool kexec_on_panic = flags & KEXEC_FILE_ON_CRASH;
 
        image = do_kimage_alloc_init();
        if (!image)
@@ -555,6 +556,12 @@ kimage_file_alloc_init(struct kimage **rimage, int kernel_fd,
 
        image->file_mode = 1;
 
+       if (kexec_on_panic) {
+               /* Enable special crash kernel control page alloc policy. */
+               image->control_page = crashk_res.start;
+               image->type = KEXEC_TYPE_CRASH;
+       }
+
        ret = kimage_file_prepare_segments(image, kernel_fd, initrd_fd,
                                           cmdline_ptr, cmdline_len, flags);
        if (ret)
@@ -572,10 +579,12 @@ kimage_file_alloc_init(struct kimage **rimage, int kernel_fd,
                goto out_free_post_load_bufs;
        }
 
-       image->swap_page = kimage_alloc_control_pages(image, 0);
-       if (!image->swap_page) {
-               pr_err(KERN_ERR "Could not allocate swap buffer\n");
-               goto out_free_control_pages;
+       if (!kexec_on_panic) {
+               image->swap_page = kimage_alloc_control_pages(image, 0);
+               if (!image->swap_page) {
+                       pr_err(KERN_ERR "Could not allocate swap buffer\n");
+                       goto out_free_control_pages;
+               }
        }
 
        *rimage = image;
@@ -1113,10 +1122,14 @@ static int kimage_load_crash_segment(struct kimage *image,
        unsigned long maddr;
        size_t ubytes, mbytes;
        int result;
-       unsigned char __user *buf;
+       unsigned char __user *buf = NULL;
+       unsigned char *kbuf = NULL;
 
        result = 0;
-       buf = segment->buf;
+       if (image->file_mode)
+               kbuf = segment->kbuf;
+       else
+               buf = segment->buf;
        ubytes = segment->bufsz;
        mbytes = segment->memsz;
        maddr = segment->mem;
@@ -1139,7 +1152,12 @@ static int kimage_load_crash_segment(struct kimage *image,
                        /* Zero the trailing part of the page */
                        memset(ptr + uchunk, 0, mchunk - uchunk);
                }
-               result = copy_from_user(ptr, buf, uchunk);
+
+               /* For file based kexec, source pages are in kernel memory */
+               if (image->file_mode)
+                       memcpy(ptr, kbuf, uchunk);
+               else
+                       result = copy_from_user(ptr, buf, uchunk);
                kexec_flush_icache_page(page);
                kunmap(page);
                if (result) {
@@ -1148,7 +1166,10 @@ static int kimage_load_crash_segment(struct kimage *image,
                }
                ubytes -= uchunk;
                maddr  += mchunk;
-               buf += mchunk;
+               if (image->file_mode)
+                       kbuf += mchunk;
+               else
+                       buf += mchunk;
                mbytes -= mchunk;
        }
 out:
@@ -2127,7 +2148,14 @@ int kexec_add_buffer(struct kimage *image, char *buffer, unsigned long bufsz,
        kbuf->top_down = top_down;
 
        /* Walk the RAM ranges and allocate a suitable range for the buffer */
-       ret = walk_system_ram_res(0, -1, kbuf, locate_mem_hole_callback);
+       if (image->type == KEXEC_TYPE_CRASH)
+               ret = walk_iomem_res("Crash kernel",
+                                    IORESOURCE_MEM | IORESOURCE_BUSY,
+                                    crashk_res.start, crashk_res.end, kbuf,
+                                    locate_mem_hole_callback);
+       else
+               ret = walk_system_ram_res(0, -1, kbuf,
+                                         locate_mem_hole_callback);
        if (ret != 1) {
                /* A suitable memory range could not be found for buffer */
                return -EADDRNOTAVAIL;