On Thu, Nov 29, 2018 at 12:32:46PM -0500, Masayoshi Mizuma wrote: >Hi Chao, > >Thank you for your continued working.
Thanks for your test. > >Could you please build your patches before sending? Sorry for the mistake, I build it with the whole patches. I found there are some problems with the method to splite patch. I will rework on it and build every commit. Thanks, Chao Fan >Your patches depend on the following kconfig, >so please build them under the config combination. > >RANDOMIZE_BASE >MEMORY_HOTREMOVE >EARLY_PARSE_RSDP >KEXEC >EFI > >Thanks, >Masa > >On Thu, Nov 29, 2018 at 04:16:26PM +0800, Chao Fan wrote: >> ***Background: >> People reported that KASLR may randomly choose some positions >> which are located in movable memory regions. This will break memory >> hotplug feature and make the movable memory chosen by KASLR can't be >> removed. >> >> ***Solutions: >> Get the information of memory hot-remove, then KASLR will know the >> right regions. Information about memory hot-remove is in ACPI >> tables, which will be parsed after start_kernel(), so that KASLR >> can't get the information. >> >> Somebody suggest to add a kernel parameter to specify the >> immovable memory so that limit KASLR in these regions. Then I make >> a patchset. After several versions, Ingo gave a suggestion: >> https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1634024.html >> Follow Ingo's suggestion, imitate the ACPI code to parse the ACPI >> tables, so that the kaslr can get necessary memory information in >> ACPI tables. >> I think ACPI code is an independent part, so imitate the codes >> and functions to 'compressed/' directory, so that kaslr won't >> influence the initialization of ACPI. >> >> PATCH 1/5 Add get_acpi_rsdp() to parse RSDP in cmdline from KEXEC >> PATCH 2/5 Add efi_get_rsdp_addr() to find RSDP from EFI table when >> booting from EFI. >> PATCH 3/5 Add bios_get_rsdp_addr() to search RSDP in memory when EFI >> table not found. >> PATCH 4/5 Compute SRAT table from RSDP and walk SRAT table to store >> the immovable memory regions. >> PATCH 5/5 Calculate the intersection between memory regions from e820/efi >> memory table and immovable memory regions. Limit KASLR to >> choosing these regions for randomization. >> >> v1->v2: >> - Simplify some code. >> Follow Baoquan He's suggestion: >> - Reuse the head file of acpi code. >> >> v2->v3: >> - Test in more conditions, so remove the 'RFC' tag. >> - Change some comments. >> >> v3->v4: >> Follow Thomas Gleixner's suggetsion: >> - Put the whole efi related function into #define CONFIG_EFI and return >> false in the other stub. >> >> v4->v5: >> Follow Dou Liyang's suggestion: >> - Add more comments about some functions based on kernel code. >> - Change some typo in comments. >> - Clean useless variable. >> - Add check for the boundary of array. >> - Add check for 'movable_node' parameter >> >> v5->v6: >> Follow Baoquan He's suggestion: >> - Change some log. >> - Add the check for acpi_rsdp >> - Change some code logical to make code clear >> >> v6->v7: >> Follow Rafael's suggestion: >> - Add more comments and patch log. >> Follow test robot's suggestion: >> - Add "static" tag for function >> >> v7-v8: >> Follow Kees Cook's suggestion: >> - Use mem_overlaps() to check memory region. >> - Use #ifdef in the definition of function. >> >> v8-v9: >> Follow Boris' suggestion: >> - Change code style. >> - Splite PATCH 1/3 to more path. >> - Introduce some new function >> - Use existing function to rework some code >> Follow Masayoshi's suggetion: >> - Make code more readable >> >> v9->v10: >> Follow Baoquan's suggestion: >> - Change some log >> - Merge last two patch together. >> >> v10->v11: >> Follow Boris' suggestion: >> - Link kstrtoull() instead of copying it. >> - Drop the useless wrapped function. >> >> v11->v12: >> Follow Boris' suggestion: >> - Change patch log and code comments. >> - Add 'CONFIG_EARLY_PARSE_RSDP' to make code easy to read >> - Put strtoull() to misc.c >> Follow Masa's suggestion: >> - Remove the detection for 'movable_node' >> - Change the code logical about cmdline_find_option() >> >> Any comments will be welcome. >> >> >> Chao Fan (5): >> x86/boot: Add get_acpi_rsdp() to parse RSDP in cmdline from KEXEC >> x86/boot: Add efi_get_rsdp_addr() to find RSDP from EFI table >> x86/boot: Add bios_get_rsdp_addr() to search RSDP in memory >> x86/boot: Parse SRAT table from RSDP and store immovable memory >> x86/boot/KASLR: Limit KASLR to extracting kernel in immovable memory >> >> arch/x86/Kconfig | 10 + >> arch/x86/boot/compressed/Makefile | 2 + >> arch/x86/boot/compressed/acpitb.c | 322 ++++++++++++++++++++++++++++++ >> arch/x86/boot/compressed/kaslr.c | 79 ++++++-- >> arch/x86/boot/compressed/misc.c | 5 + >> arch/x86/boot/compressed/misc.h | 24 +++ >> lib/kstrtox.c | 5 + >> 7 files changed, 432 insertions(+), 15 deletions(-) >> create mode 100644 arch/x86/boot/compressed/acpitb.c >> >> -- >> 2.19.1 >> >> >> > >
