Re: [PATCH] powerpc: Fix loading of kernel + initramfs with kexec_file_load()

From: Dave Young <dyoung@redhat.com>
To: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>,
	kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
	Mimi Zohar <zohar@linux.ibm.com>,
	AKASHI Takahiro <takahiro.akashi@linaro.org>,
	linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH] powerpc: Fix loading of kernel + initramfs with kexec_file_load()
Date: Thu, 23 May 2019 11:23:02 +0800	[thread overview]
Message-ID: <20190523032302.GD8174@dhcp-128-65.nay.redhat.com> (raw)
In-Reply-To: <20190522220158.18479-1-bauerman@linux.ibm.com>

On 05/22/19 at 07:01pm, Thiago Jung Bauermann wrote:
> 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@linux.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;
> 
> 
> _______________________________________________
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> kexec@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/kexec

Reviewed-by: Dave Young <dyoung@redhat.com>

Thanks
Dave

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