Hi Chao, Thank you for your continued working.
Could you please build your patches before sending? 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 > > >
