Re: [PATCH] kexec/ppc: Fix kernel program entry point while changing the load addr
On Mon, Mar 04, 2013 at 11:26:24AM +0530, Suzuki K. Poulose wrote: 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 suz...@in.ibm.com 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, I have applied the patch. ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: [PATCH] kexec/ppc: Fix kernel program entry point while changing the load addr
[ Cc: linuxppc-dev@lists.ozlabs.org ] On Sun, Mar 03, 2013 at 01:06:00PM +0530, Suzuki K. Poulose wrote: From: Suzuki K. Poulose suz...@in.ibm.com 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? Signed-off-by: Suzuki K. Poulose suz...@in.ibm.com Cc: Sebastian Andrzej Siewior bige...@linutronix.de Cc: Matthew McClintock m...@freescale.com --- 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 ke...@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
Re: [PATCH] kexec/ppc: Fix kernel program entry point while changing the load addr
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 suz...@in.ibm.com 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 suz...@in.ibm.com Cc: Sebastian Andrzej Siewior bige...@linutronix.de Cc: Matthew McClintock m...@freescale.com --- 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 ke...@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 ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev