Messages in this thread |  | | Date | Fri, 10 Aug 2018 18:28:46 +0800 | From | Dave Young <> | Subject | Re: [PATCH] x86, kdump: Fix efi=noruntime NULL pointer dereference |
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On 08/10/18 at 04:45pm, Dave Young wrote: > On 08/08/18 at 04:03pm, Mike Galbraith wrote: > > When booting with efi=noruntime, we call efi_runtime_map_copy() while > > loading the kdump kernel, and trip over a NULL efi.memmap.map. Avoid > > that and a useless allocation when the only mapping we can use (1:1) > > is not available. > > > > Signed-off-by: Mike Galbraith <efault@gmx.de> > > --- > > arch/x86/kernel/kexec-bzimage64.c | 22 +++++++++++----------- > > 1 file changed, 11 insertions(+), 11 deletions(-) > > > > --- a/arch/x86/kernel/kexec-bzimage64.c > > +++ b/arch/x86/kernel/kexec-bzimage64.c > > @@ -122,9 +122,6 @@ static int setup_efi_info_memmap(struct > > unsigned long efi_map_phys_addr = params_load_addr + efi_map_offset; > > struct efi_info *ei = ¶ms->efi_info; > > > > - if (!efi_map_sz) > > - return 0; > > - > > efi_runtime_map_copy(efi_map, efi_map_sz); > > > > ei->efi_memmap = efi_map_phys_addr & 0xffffffff; > > @@ -176,7 +173,7 @@ setup_efi_state(struct boot_params *para > > * acpi_rsdp=<addr> on kernel command line to make second kernel boot > > * without efi. > > */ > > - if (efi_enabled(EFI_OLD_MEMMAP)) > > + if (efi_enabled(EFI_OLD_MEMMAP) || !efi_enabled(EFI_MEMMAP)) > > return 0; > > > > ei->efi_loader_signature = current_ei->efi_loader_signature; > > @@ -338,7 +335,7 @@ static void *bzImage64_load(struct kimag > > struct kexec_entry64_regs regs64; > > void *stack; > > unsigned int setup_hdr_offset = offsetof(struct boot_params, hdr); > > - unsigned int efi_map_offset, efi_map_sz, efi_setup_data_offset; > > + unsigned int efi_map_offset = 0, efi_map_sz = 0, efi_setup_data_offset = 0; > > struct kexec_buf kbuf = { .image = image, .buf_max = ULONG_MAX, > > .top_down = true }; > > struct kexec_buf pbuf = { .image = image, .buf_min = MIN_PURGATORY_ADDR, > > @@ -397,19 +394,22 @@ static void *bzImage64_load(struct kimag > > * have to create separate segment for each. Keeps things > > * little bit simple > > */ > > - efi_map_sz = efi_get_runtime_map_size(); > > params_cmdline_sz = sizeof(struct boot_params) + cmdline_len + > > MAX_ELFCOREHDR_STR_LEN; > > params_cmdline_sz = ALIGN(params_cmdline_sz, 16); > > - kbuf.bufsz = params_cmdline_sz + ALIGN(efi_map_sz, 16) + > > - sizeof(struct setup_data) + > > - sizeof(struct efi_setup_data); > > + kbuf.bufsz = params_cmdline_sz + sizeof(struct setup_data); > > + > > + /* Now add space for the efi stuff if we have a useable 1:1 mapping. */ > > + if (!efi_enabled(EFI_OLD_MEMMAP) && efi_enabled(EFI_MEMMAP)) { > > + efi_map_sz = efi_get_runtime_map_size(); > > + kbuf.bufsz += ALIGN(efi_map_sz, 16) + sizeof(struct efi_setup_data); > > + efi_map_offset = params_cmdline_sz; > > + efi_setup_data_offset = efi_map_offset + ALIGN(efi_map_sz, 16); > > + } > > > > params = kzalloc(kbuf.bufsz, GFP_KERNEL); > > if (!params) > > return ERR_PTR(-ENOMEM); > > - efi_map_offset = params_cmdline_sz; > > - efi_setup_data_offset = efi_map_offset + ALIGN(efi_map_sz, 16); > > > > /* Copy setup header onto bootparams. Documentation/x86/boot.txt */ > > setup_header_size = 0x0202 + kernel[0x0201] - setup_hdr_offset; > > BTW, this patch only fix the kexec load phase problem, even if kexec > load successfully with the fix, the 2nd kernel can not boot because efi > memmap info is not correct and usable. > > So we should go with some fix similar to below, and do the cleanup we > mentioned with a separate patch later. > > Also user space kexec-tools need a similar patch to error out in case > no runtime maps. It would be good to fix both userspace and kernel > load. > > diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c > index 7326078eaa7a..e34ba2f53cfb 100644 > --- a/arch/x86/kernel/kexec-bzimage64.c > +++ b/arch/x86/kernel/kexec-bzimage64.c > @@ -123,7 +123,7 @@ static int setup_efi_info_memmap(struct boot_params *params, > struct efi_info *ei = ¶ms->efi_info; > > if (!efi_map_sz) > - return 0; > + return -EINVAL; > > efi_runtime_map_copy(efi_map, efi_map_sz); > > @@ -166,9 +166,10 @@ setup_efi_state(struct boot_params *params, unsigned long params_load_addr, > { > struct efi_info *current_ei = &boot_params.efi_info; > struct efi_info *ei = ¶ms->efi_info; > + int ret; > > if (!current_ei->efi_memmap_size) > - return 0; > + return -EINVAL; > > /* > * If 1:1 mapping is not enabled, second kernel can not setup EFI > @@ -176,8 +177,8 @@ setup_efi_state(struct boot_params *params, unsigned long params_load_addr, > * acpi_rsdp=<addr> on kernel command line to make second kernel boot > * without efi. > */ > - if (efi_enabled(EFI_OLD_MEMMAP)) > - return 0; > + if (efi_enabled(EFI_OLD_MEMMAP) || !efi_enabled(EFI_RUNTIME_SERVICES)) > + return -ENODEV; > > ei->efi_loader_signature = current_ei->efi_loader_signature; > ei->efi_systab = current_ei->efi_systab; > @@ -186,8 +187,10 @@ setup_efi_state(struct boot_params *params, unsigned long params_load_addr, > ei->efi_memdesc_version = current_ei->efi_memdesc_version; > ei->efi_memdesc_size = efi_get_runtime_map_desc_size(); > > - setup_efi_info_memmap(params, params_load_addr, efi_map_offset, > + ret = setup_efi_info_memmap(params, params_load_addr, efi_map_offset, > efi_map_sz); > + if (ret) > + return ret; > prepare_add_efi_setup_data(params, params_load_addr, > efi_setup_data_offset); > return 0; > @@ -250,8 +253,10 @@ setup_boot_parameters(struct kimage *image, struct boot_params *params, > > #ifdef CONFIG_EFI > /* Setup EFI state */ > - setup_efi_state(params, params_load_addr, efi_map_offset, efi_map_sz, > + ret = setup_efi_state(params, params_load_addr, efi_map_offset, efi_map_sz, > efi_setup_data_offset); > + if (ret)
Here should check efi_enabled(EFI_BOOT) && ret
In case efi boot we need the efi info set correctly, or one need pass acpi_rsdp= in kernel cmdline param.
Still not sure how to allow one to workaround it by using acpi_rsdp= param with kexec_file_load..
> + return ret; > #endif > > /* Setup EDD info */
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