Merge tag 'kexec-v7.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/liveupdate/linux

Pull kexec updates from Mike Rapoport:

 - Fix probe error codes and error propagation:

     - make architecture functions that probe loaded image consistenly
       return -ENOEXEC when they do not recognize the image format

     - make kexec_image_probe_default() distinguish image format
       mismatches (-ENOEXEC) from real errors (e.g. -ENOMEM),
       propagating real errors immediately and only continuing to the
       next loader on -ENOEXEC

 - Make sure the next kernel does not land on hardware-poisoned pages

 - Remove unused arch_kexec_locate_mem_hole hook

* tag 'kexec-v7.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/liveupdate/linux:
  kexec_file: remove unused arch_kexec_locate_mem_hole hook
  kexec: fix error propagation in kexec_image_probe_default()
  kexec: return -ENOEXEC from image probe functions on mismatch
  kexec: keep the next kernel off hardware-poisoned pages
  kexec_file: stop the top-down search before it underflows

3 files changed, 39 insertions, 9 deletions

diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index dc770b9a6d05..7ee8c9f078f6 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -213,6 +213,16 @@ int sanity_check_segment_list(struct kimage *image)
 #endif
 
 	/*
+	 * Reject destinations that land on hardware-poisoned memory: the
+	 * relocation copy would machine-check on the bad frame.
+	 */
+	for (i = 0; i < nr_segments; i++) {
+		if (range_first_hwpoison(image->segment[i].mem,
+					 image->segment[i].memsz) != PHYS_ADDR_MAX)
+			return -EHWPOISON;
+	}
+
+	/*
 	 * The destination addresses are searched from system RAM rather than
 	 * being allocated from the buddy allocator, so they are not guaranteed
 	 * to be accepted by the current kernel.  Accept the destination
diff --git a/kernel/kexec_elf.c b/kernel/kexec_elf.c
index 3a5c25b2adc9..89a444a00693 100644
--- a/kernel/kexec_elf.c
+++ b/kernel/kexec_elf.c
@@ -172,7 +172,7 @@ static int elf_read_ehdr(const char *buf, size_t len, struct elfhdr *ehdr)
 
 	default:
 		pr_debug("Unknown ELF class.\n");
-		return -EINVAL;
+		return -ENOEXEC;
 	}
 
 	return elf_is_ehdr_sane(ehdr, len) ? 0 : -ENOEXEC;
@@ -236,7 +236,7 @@ static int elf_read_phdr(const char *buf, size_t len,
 
 	default:
 		pr_debug("Unknown ELF class.\n");
-		return -EINVAL;
+		return -ENOEXEC;
 	}
 
 	return elf_is_phdr_sane(phdr, len) ? 0 : -ENOEXEC;
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 59fb9d71e9d8..a8455481f639 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -68,17 +68,19 @@ int kexec_image_probe_default(struct kimage *image, void *buf,
 			      unsigned long buf_len)
 {
 	const struct kexec_file_ops * const *fops;
-	int ret = -ENOEXEC;
 
 	for (fops = &kexec_file_loaders[0]; *fops && (*fops)->probe; ++fops) {
-		ret = (*fops)->probe(buf, buf_len);
-		if (!ret) {
+		int err = (*fops)->probe(buf, buf_len);
+
+		if (!err) {
 			image->fops = *fops;
-			return ret;
+			return 0;
 		}
+		if (err != -ENOEXEC)
+			return err;
 	}
 
-	return ret;
+	return -ENOEXEC;
 }
 
 static void *kexec_image_load_default(struct kimage *image)
@@ -475,6 +477,7 @@ static int locate_mem_hole_top_down(unsigned long start, unsigned long end,
 {
 	struct kimage *image = kbuf->image;
 	unsigned long temp_start, temp_end;
+	phys_addr_t poison;
 
 	temp_end = min(end, kbuf->buf_max);
 	temp_start = temp_end - kbuf->memsz + 1;
@@ -484,7 +487,9 @@ static int locate_mem_hole_top_down(unsigned long start, unsigned long end,
 		/* align down start */
 		temp_start = ALIGN_DOWN(temp_start, kbuf->buf_align);
 
-		if (temp_start < start || temp_start < kbuf->buf_min)
+		/* A candidate above the range means the walk wrapped around */
+		if (temp_start < start || temp_start < kbuf->buf_min ||
+		    temp_start > end)
 			return 0;
 
 		temp_end = temp_start + kbuf->memsz - 1;
@@ -504,6 +509,13 @@ static int locate_mem_hole_top_down(unsigned long start, unsigned long end,
 			continue;
 		}
 
+		poison = range_first_hwpoison(temp_start, kbuf->memsz);
+		if (poison != PHYS_ADDR_MAX) {
+			/* we hit a poisoned page */
+			temp_start = poison - kbuf->memsz;
+			continue;
+		}
+
 		/* We found a suitable memory range */
 		break;
 	} while (1);
@@ -520,6 +532,7 @@ static int locate_mem_hole_bottom_up(unsigned long start, unsigned long end,
 {
 	struct kimage *image = kbuf->image;
 	unsigned long temp_start, temp_end;
+	phys_addr_t poison;
 
 	temp_start = max(start, kbuf->buf_min);
 
@@ -546,6 +559,13 @@ static int locate_mem_hole_bottom_up(unsigned long start, unsigned long end,
 			continue;
 		}
 
+		poison = range_last_hwpoison(temp_start, kbuf->memsz);
+		if (poison != PHYS_ADDR_MAX) {
+			/* we hit a poisoned page */
+			temp_start = poison + PAGE_SIZE;
+			continue;
+		}
+
 		/* We found a suitable memory range */
 		break;
 	} while (1);
@@ -784,7 +804,7 @@ int kexec_add_buffer(struct kexec_buf *kbuf)
 	kbuf->cma = NULL;
 
 	/* Walk the RAM ranges and allocate a suitable range for the buffer */
-	ret = arch_kexec_locate_mem_hole(kbuf);
+	ret = kexec_locate_mem_hole(kbuf);
 	if (ret)
 		return ret;