linux-kernel - [PATCH] powerpc: Fix loading of kernel + initramfs with kexec_file

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Message-Id: <20190522220158.18479-1-bauerman@linux.ibm.com>
Date:   Wed, 22 May 2019 19:01:58 -0300
From:   Thiago Jung Bauermann <bauerman@...ux.ibm.com>
To:     linuxppc-dev@...ts.ozlabs.org
Cc:     kexec@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Michael Ellerman <mpe@...erman.id.au>,
        AKASHI Takahiro <takahiro.akashi@...aro.org>,
        Mimi Zohar <zohar@...ux.ibm.com>,
        Thiago Jung Bauermann <bauerman@...ux.ibm.com>
Subject: [PATCH] powerpc: 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()")
Signed-off-by: Thiago Jung Bauermann <bauerman@...ux.ibm.com>
---
 arch/powerpc/kernel/kexec_elf_64.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

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;