From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e28smtp06.in.ibm.com (e28smtp06.in.ibm.com [122.248.162.6]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e28smtp06.in.ibm.com", Issuer "GeoTrust SSL CA" (not verified)) by ozlabs.org (Postfix) with ESMTPS id C4F652C0302 for ; Mon, 4 Mar 2013 16:56:40 +1100 (EST) Received: from /spool/local by e28smtp06.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 4 Mar 2013 11:23:08 +0530 Received: from d28relay03.in.ibm.com (d28relay03.in.ibm.com [9.184.220.60]) by d28dlp01.in.ibm.com (Postfix) with ESMTP id 989A6E0050 for ; Mon, 4 Mar 2013 11:27:38 +0530 (IST) Received: from d28av03.in.ibm.com (d28av03.in.ibm.com [9.184.220.65]) by d28relay03.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r245uN3o32440552 for ; Mon, 4 Mar 2013 11:26:23 +0530 Received: from d28av03.in.ibm.com (loopback [127.0.0.1]) by d28av03.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r245uQOd011087 for ; Mon, 4 Mar 2013 16:56:27 +1100 Message-ID: <51343788.7070503@in.ibm.com> Date: Mon, 04 Mar 2013 11:26:24 +0530 From: "Suzuki K. Poulose" MIME-Version: 1.0 To: Simon Horman Subject: Re: [PATCH] kexec/ppc: Fix kernel program entry point while changing the load addr References: <20130303073540.12040.16854.stgit@suzukikp> <20130304014152.GB9007@verge.net.au> In-Reply-To: <20130304014152.GB9007@verge.net.au> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Cc: Matthew McClintock , Sebastian Andrzej Siewior , kexec@lists.infradead.org, linuxppc-dev@lists.ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 03/04/2013 07:11 AM, Simon Horman wrote: > [ Cc: linuxppc-dev@lists.ozlabs.org ] > > On Sun, Mar 03, 2013 at 01:06:00PM +0530, Suzuki K. Poulose wrote: >> From: Suzuki K. Poulose >> >> uImage probe fills the entry point (ep) based on the load_addr >> from the uImage headers. If we change the load_addr, we should >> accordingly update the entry point. >> >> For ELF, calculate the offset of e_entry from the virtual start >> address and add it to the physical start address to find the >> physical address of kernel entry. >> >> i.e, >> pa (e_entry) = pa(phdr[0].p_vaddr) + (e_entry - phdr[0].p_vaddr) >> = kernel_addr + (e_entry - phdr[0].p_vaddr) > > Would it be possible for someone to provide a review of this change? To make it bit more clear : The entry point of the kernel is usually at 0 offset from the first PT_LOAD section. The current code makes this assumption and uses the pa(phdr[0].p_vaddr) as the kernel entry. But this *may* not be true always, in such a case the kexec would fail. While I fixed the uImage case, I thought it would be better to handle the same case in ELF. Btw, this calculation is not specific to ppc32. Thanks Suzuki > >> >> Signed-off-by: Suzuki K. Poulose >> Cc: Sebastian Andrzej Siewior >> Cc: Matthew McClintock >> --- >> kexec/arch/ppc/kexec-elf-ppc.c | 12 ++++++++---- >> kexec/arch/ppc/kexec-uImage-ppc.c | 6 +++++- >> 2 files changed, 13 insertions(+), 5 deletions(-) >> >> diff --git a/kexec/arch/ppc/kexec-elf-ppc.c b/kexec/arch/ppc/kexec-elf-ppc.c >> index 8e408cc..5f63a64 100644 >> --- a/kexec/arch/ppc/kexec-elf-ppc.c >> +++ b/kexec/arch/ppc/kexec-elf-ppc.c >> @@ -397,10 +397,14 @@ int elf_ppc_load(int argc, char **argv, const char *buf, off_t len, >> die("Error device tree not loadded to address it was expecting to be loaded too!\n"); >> } >> >> - /* set various variables for the purgatory ehdr.e_entry is a >> - * virtual address, we can use kernel_addr which >> - * should be the physical start address of the kernel */ >> - addr = kernel_addr; >> + /* >> + * set various variables for the purgatory. >> + * ehdr.e_entry is a virtual address. we know physical start >> + * address of the kernel (kernel_addr). Find the offset of >> + * e_entry from the virtual start address(e_phdr[0].p_vaddr) >> + * and calculate the actual physical address of the 'kernel entry'. >> + */ >> + addr = kernel_addr + (ehdr.e_entry - ehdr.e_phdr[0].p_vaddr); >> elf_rel_set_symbol(&info->rhdr, "kernel", &addr, sizeof(addr)); >> >> addr = dtb_addr; >> diff --git a/kexec/arch/ppc/kexec-uImage-ppc.c b/kexec/arch/ppc/kexec-uImage-ppc.c >> index e0bc7bb..900cd16 100644 >> --- a/kexec/arch/ppc/kexec-uImage-ppc.c >> +++ b/kexec/arch/ppc/kexec-uImage-ppc.c >> @@ -159,15 +159,19 @@ static int ppc_load_bare_bits(int argc, char **argv, const char *buf, >> >> /* >> * If the provided load_addr cannot be allocated, find a new >> - * area. >> + * area. Rebase the entry point based on the new load_addr. >> */ >> if (!valid_memory_range(info, load_addr, load_addr + (len + _1MiB))) { >> + int ep_offset = ep - load_addr; >> + >> load_addr = locate_hole(info, len + _1MiB, 0, 0, max_addr, 1); >> if (load_addr == ULONG_MAX) { >> printf("Can't allocate memory for kernel of len %ld\n", >> len + _1MiB); >> return -1; >> } >> + >> + ep = load_addr + ep_offset; >> } >> >> add_segment(info, buf, len, load_addr, len + _1MiB); >> >> >> _______________________________________________ >> kexec mailing list >> kexec@lists.infradead.org >> http://lists.infradead.org/mailman/listinfo/kexec >> > _______________________________________________ > Linuxppc-dev mailing list > Linuxppc-dev@lists.ozlabs.org > https://lists.ozlabs.org/listinfo/linuxppc-dev >