@@ -362,6 +362,13 @@ struct kimage {
size_t ima_buffer_size;
#endif
+#ifdef CONFIG_KEXEC_KHO
+ struct {
+ struct kexec_buf dt;
+ struct kexec_buf mem_cache;
+ } kho;
+#endif
+
/* Core ELF header buffer */
void *elf_headers;
unsigned long elf_headers_sz;
@@ -543,6 +550,7 @@ static inline bool is_kho_boot(void)
/* egest handover metadata */
void kho_reserve_scratch(void);
+int kho_fill_kimage(struct kimage *image);
int register_kho_notifier(struct notifier_block *nb);
int unregister_kho_notifier(struct notifier_block *nb);
bool kho_is_active(void);
@@ -560,6 +568,7 @@ static inline bool is_kho_boot(void) { return false; }
/* egest handover metadata */
static inline void kho_reserve_scratch(void) { }
+static inline int kho_fill_kimage(struct kimage *image) { return 0; }
static inline int register_kho_notifier(struct notifier_block *nb) { return -EINVAL; }
static inline int unregister_kho_notifier(struct notifier_block *nb) { return -EINVAL; }
static inline bool kho_is_active(void) { return false; }
@@ -113,6 +113,13 @@ void kimage_file_post_load_cleanup(struct kimage *image)
image->ima_buffer = NULL;
#endif /* CONFIG_IMA_KEXEC */
+#ifdef CONFIG_KEXEC_KHO
+ kvfree(image->kho.mem_cache.buffer);
+ image->kho.mem_cache = (struct kexec_buf) {};
+ kvfree(image->kho.dt.buffer);
+ image->kho.dt = (struct kexec_buf) {};
+#endif
+
/* See if architecture has anything to cleanup post load */
arch_kimage_file_post_load_cleanup(image);
@@ -249,6 +256,11 @@ kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
/* IMA needs to pass the measurement list to the next kernel. */
ima_add_kexec_buffer(image);
+ /* If KHO is active, add its images to the list */
+ ret = kho_fill_kimage(image);
+ if (ret)
+ goto out;
+
/* Call image load handler */
ldata = kexec_image_load_default(image);
@@ -518,6 +530,24 @@ static int locate_mem_hole_callback(struct resource *res, void *arg)
return locate_mem_hole_bottom_up(start, end, kbuf);
}
+#ifdef CONFIG_KEXEC_KHO
+static int kexec_walk_kho_scratch(struct kexec_buf *kbuf,
+ int (*func)(struct resource *, void *))
+{
+ int ret = 0;
+
+ struct resource res = {
+ .start = kho_scratch_phys,
+ .end = kho_scratch_phys + kho_scratch_len,
+ };
+
+ /* Try to fit the kimage into our KHO scratch region */
+ ret = func(&res, kbuf);
+
+ return ret;
+}
+#endif
+
#ifdef CONFIG_ARCH_KEEP_MEMBLOCK
static int kexec_walk_memblock(struct kexec_buf *kbuf,
int (*func)(struct resource *, void *))
@@ -612,6 +642,17 @@ int kexec_locate_mem_hole(struct kexec_buf *kbuf)
if (kbuf->mem != KEXEC_BUF_MEM_UNKNOWN)
return 0;
+#ifdef CONFIG_KEXEC_KHO
+ /*
+ * If KHO is active, only use KHO scratch memory. All other memory
+ * could potentially be handed over.
+ */
+ if (kho_is_active() && kbuf->image->type != KEXEC_TYPE_CRASH) {
+ ret = kexec_walk_kho_scratch(kbuf, locate_mem_hole_callback);
+ return ret == 1 ? 0 : -EADDRNOTAVAIL;
+ }
+#endif
+
if (!IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK))
ret = kexec_walk_resources(kbuf, locate_mem_hole_callback);
else
@@ -50,6 +50,216 @@ int unregister_kho_notifier(struct notifier_block *nb)
}
EXPORT_SYMBOL_GPL(unregister_kho_notifier);
+static int kho_mem_cache_add(void *fdt, struct kho_mem *mem_cache, int size,
+ struct kho_mem *new_mem)
+{
+ int entries = size / sizeof(*mem_cache);
+ u64 new_start = new_mem->addr;
+ u64 new_end = new_mem->addr + new_mem->len;
+ u64 prev_start = 0;
+ u64 prev_end = 0;
+ int i;
+
+ if (WARN_ON((new_start < (kho_scratch_phys + kho_scratch_len)) &&
+ (new_end > kho_scratch_phys))) {
+ pr_err("KHO memory runs over scratch memory");
+ return -EINVAL;
+ }
+
+ /*
+ * We walk the existing sorted mem cache and find the spot where this
+ * new entry would start, so we can insert it right there.
+ */
+ for (i = 0; i < entries; i++) {
+ struct kho_mem *mem = &mem_cache[i];
+ u64 mem_end = (mem->addr + mem->len);
+
+ if (mem_end < new_start) {
+ /* No overlap */
+ prev_start = mem->addr;
+ prev_end = mem->addr + mem->len;
+ continue;
+ } else if ((new_start >= mem->addr) && (new_end <= mem_end)) {
+ /* new_mem fits into mem, skip */
+ return size;
+ } else if ((new_end >= mem->addr) && (new_start <= mem_end)) {
+ /* new_mem and mem overlap, fold them */
+ bool remove = false;
+
+ mem->addr = min(new_start, mem->addr);
+ mem->len = max(mem_end, new_end) - mem->addr;
+ mem_end = (mem->addr + mem->len);
+
+ if (i > 0 && prev_end >= mem->addr) {
+ /* We now overlap with the previous mem, fold */
+ struct kho_mem *prev = &mem_cache[i - 1];
+
+ prev->addr = min(prev->addr, mem->addr);
+ prev->len = max(mem_end, prev_end) - prev->addr;
+ remove = true;
+ } else if (i < (entries - 1) && mem_end >= mem_cache[i + 1].addr) {
+ /* We now overlap with the next mem, fold */
+ struct kho_mem *next = &mem_cache[i + 1];
+ u64 next_end = (next->addr + next->len);
+
+ next->addr = min(next->addr, mem->addr);
+ next->len = max(mem_end, next_end) - next->addr;
+ remove = true;
+ }
+
+ if (remove) {
+ /* We folded this mem into another, remove it */
+ memmove(mem, mem + 1, (entries - i - 1) * sizeof(*mem));
+ size -= sizeof(*new_mem);
+ }
+
+ return size;
+ } else if (mem->addr > new_end) {
+ /*
+ * The mem cache is sorted. If we find the current
+ * entry start after our new_mem's end, we shot over
+ * which means we need to add it by creating a new
+ * hole right after the current entry.
+ */
+ memmove(mem + 1, mem, (entries - i) * sizeof(*mem));
+ break;
+ }
+ }
+
+ mem_cache[i] = *new_mem;
+ size += sizeof(*new_mem);
+
+ return size;
+}
+
+/**
+ * kho_alloc_mem_cache - Allocate and initialize the mem cache kexec_buf
+ */
+static int kho_alloc_mem_cache(struct kimage *image, void *fdt)
+{
+ int offset, depth, initial_depth, len;
+ void *mem_cache;
+ int size;
+
+ /* Count the elements inside all "mem" properties in the DT */
+ size = offset = depth = initial_depth = 0;
+ for (offset = 0;
+ offset >= 0 && depth >= initial_depth;
+ offset = fdt_next_node(fdt, offset, &depth)) {
+ const struct kho_mem *mems;
+
+ mems = fdt_getprop(fdt, offset, "mem", &len);
+ if (!mems || len & (sizeof(*mems) - 1))
+ continue;
+ size += len;
+ }
+
+ /* Allocate based on the max size we determined */
+ mem_cache = kvmalloc(size, GFP_KERNEL);
+ if (!mem_cache)
+ return -ENOMEM;
+
+ /* And populate the array */
+ size = offset = depth = initial_depth = 0;
+ for (offset = 0;
+ offset >= 0 && depth >= initial_depth;
+ offset = fdt_next_node(fdt, offset, &depth)) {
+ const struct kho_mem *mems;
+ int nr_mems, i;
+
+ mems = fdt_getprop(fdt, offset, "mem", &len);
+ if (!mems || len & (sizeof(*mems) - 1))
+ continue;
+
+ for (i = 0, nr_mems = len / sizeof(*mems); i < nr_mems; i++) {
+ const struct kho_mem *mem = &mems[i];
+ ulong mstart = PAGE_ALIGN_DOWN(mem->addr);
+ ulong mend = PAGE_ALIGN(mem->addr + mem->len);
+ struct kho_mem cmem = {
+ .addr = mstart,
+ .len = (mend - mstart),
+ };
+
+ size = kho_mem_cache_add(fdt, mem_cache, size, &cmem);
+ if (size < 0)
+ return size;
+ }
+ }
+
+ image->kho.mem_cache.buffer = mem_cache;
+ image->kho.mem_cache.bufsz = size;
+ image->kho.mem_cache.memsz = size;
+
+ return 0;
+}
+
+int kho_fill_kimage(struct kimage *image)
+{
+ int err = 0;
+ void *dt;
+
+ mutex_lock(&kho.lock);
+
+ if (!kho.active)
+ goto out;
+
+ /* Initialize kexec_buf for mem_cache */
+ image->kho.mem_cache = (struct kexec_buf) {
+ .image = image,
+ .buffer = NULL,
+ .bufsz = 0,
+ .mem = KEXEC_BUF_MEM_UNKNOWN,
+ .memsz = 0,
+ .buf_align = SZ_64K, /* Makes it easier to map */
+ .buf_max = ULONG_MAX,
+ .top_down = true,
+ };
+
+ /*
+ * We need to make all allocations visible here via the mem_cache so that
+ * kho_is_destination_range() can identify overlapping regions and ensure
+ * that no kimage (including the DT one) lands on handed over memory.
+ *
+ * Since we conveniently already built an array of all allocations, let's
+ * pass that on to the target kernel so that reuse it to initialize its
+ * memory blocks.
+ */
+ err = kho_alloc_mem_cache(image, kho.dt);
+ if (err)
+ goto out;
+
+ err = kexec_add_buffer(&image->kho.mem_cache);
+ if (err)
+ goto out;
+
+ /*
+ * Create a kexec copy of the DT here. We need this because lifetime may
+ * be different between kho.dt and the kimage
+ */
+ dt = kvmemdup(kho.dt, kho.dt_len, GFP_KERNEL);
+ if (!dt) {
+ err = -ENOMEM;
+ goto out;
+ }
+
+ /* Allocate target memory for kho dt */
+ image->kho.dt = (struct kexec_buf) {
+ .image = image,
+ .buffer = dt,
+ .bufsz = kho.dt_len,
+ .mem = KEXEC_BUF_MEM_UNKNOWN,
+ .memsz = kho.dt_len,
+ .buf_align = SZ_64K, /* Makes it easier to map */
+ .buf_max = ULONG_MAX,
+ .top_down = true,
+ };
+ err = kexec_add_buffer(&image->kho.dt);
+
+out:
+ mutex_unlock(&kho.lock);
+ return err;
+}
+
bool kho_is_active(void)
{
return kho.active;