powerpc/kexec: Fix loading of kernel + initramfs with kexec_file_load()

Commit b6664ba42f14 ("s390, kexec_file: drop arch_kexec_mem_walk()")
changed kexec_add_buffer() to skip searching for a memory location if
kexec_buf.mem is already set, and use the address that is there.

In powerpc code we reuse a kexec_buf variable for loading both the
kernel and the initramfs by resetting some of the fields between those
uses, but not mem. This causes kexec_add_buffer() to try to load the
kernel at the same address where initramfs will be loaded, which is
naturally rejected:

  # kexec -s -l --initrd initramfs vmlinuz
  kexec_file_load failed: Invalid argument

Setting the mem field before every call to kexec_add_buffer() fixes
this regression.

Fixes: b6664ba42f14 ("s390, kexec_file: drop arch_kexec_mem_walk()")
Cc: stable@vger.kernel.org # v5.0+
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Reviewed-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 5 insertions, 1 deletions

diff --git a/arch/powerpc/kernel/kexec_elf_64.c b/arch/powerpc/kernel/kexec_elf_64.c
index ba4f18a43ee8..52a29fc73730 100644
--- a/arch/powerpc/kernel/kexec_elf_64.c
+++ b/arch/powerpc/kernel/kexec_elf_64.c
@@ -547,6 +547,7 @@ static int elf_exec_load(struct kimage *image, struct elfhdr *ehdr,
                 kbuf.memsz = phdr->p_memsz;
                 kbuf.buf_align = phdr->p_align;
                 kbuf.buf_min = phdr->p_paddr + base;
+                kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
                 ret = kexec_add_buffer(&kbuf);
                 if (ret)
                         goto out;
@@ -581,7 +582,8 @@ static void *elf64_load(struct kimage *image, char *kernel_buf,
         struct kexec_buf kbuf = { .image = image, .buf_min = 0,
                                   .buf_max = ppc64_rma_size };
         struct kexec_buf pbuf = { .image = image, .buf_min = 0,
-                                  .buf_max = ppc64_rma_size, .top_down = true };
+                                  .buf_max = ppc64_rma_size, .top_down = true,
+                                  .mem = KEXEC_BUF_MEM_UNKNOWN };
 
         ret = build_elf_exec_info(kernel_buf, kernel_len, &ehdr, &elf_info);
         if (ret)
@@ -606,6 +608,7 @@ static void *elf64_load(struct kimage *image, char *kernel_buf,
                 kbuf.bufsz = kbuf.memsz = initrd_len;
                 kbuf.buf_align = PAGE_SIZE;
                 kbuf.top_down = false;
+                kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
                 ret = kexec_add_buffer(&kbuf);
                 if (ret)
                         goto out;
@@ -638,6 +641,7 @@ static void *elf64_load(struct kimage *image, char *kernel_buf,
         kbuf.bufsz = kbuf.memsz = fdt_size;
         kbuf.buf_align = PAGE_SIZE;
         kbuf.top_down = true;
+        kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
         ret = kexec_add_buffer(&kbuf);
         if (ret)
                 goto out;