On Mon, Oct 15, 2018 at 04:26:09PM -0400, Masayoshi Mizuma wrote: >Hi Chao, > >Let me add some suggestions.
Thanks for your review and suggestion. I will change them in next version. Thanks, Chao Fan > >On Wed, Oct 10, 2018 at 04:41:17PM +0800, Chao Fan wrote: >> There is a bug that kaslr may randomly chooses 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. So dig SRAT table from ACPI tables to get memory information. >> >> Imitate the ACPI code of parsing ACPI tables to dig and read ACPI >> tables. Since some operations are not needed here, functions are >> simplified. Functions will be used to dig only SRAT tables to get >> information of memory, so that KASLR can the memory in immovable node. >> >> And also, these functions won't influence the initialization of >> ACPI after start_kernel(). >> >> Since use physical address directely, so acpi_os_map_memory() >> and acpi_os_unmap_memory() are not needed. >> >> Signed-off-by: Chao Fan <[email protected]> >> --- >> arch/x86/boot/compressed/Makefile | 2 + >> arch/x86/boot/compressed/acpitb.c | 405 ++++++++++++++++++++++++++++++ >> arch/x86/boot/compressed/misc.h | 8 + >> 3 files changed, 415 insertions(+) >> create mode 100644 arch/x86/boot/compressed/acpitb.c >> >...cut... >> +static struct acpi_table_header *get_acpi_srat_table(void) >> +{ >> + char *args = (char *)get_cmd_line_ptr(); >> + acpi_physical_address acpi_table; >> + acpi_physical_address root_table; >> + struct acpi_table_header *header; >> + struct acpi_table_rsdp *rsdp; >> + char *signature; >> + u8 *entry; >> + u32 count; >> + u32 size; >> + int i, j; >> + u32 len; >> + >> + rsdp = (struct acpi_table_rsdp *)get_rsdp_addr(); >> + if (!rsdp) >> + return NULL; >> + >> + /* Get rsdt or xsdt from rsdp. */ >> + if (!strstr(args, "acpi=rsdt") && >> + rsdp->xsdt_physical_address && rsdp->revision > 1) { >> + root_table = rsdp->xsdt_physical_address; >> + size = ACPI_XSDT_ENTRY_SIZE; >> + } else { >> + root_table = rsdp->rsdt_physical_address; >> + size = ACPI_RSDT_ENTRY_SIZE; >> + } >> + >> + /* Get ACPI root table from rsdt or xsdt.*/ >> + header = (struct acpi_table_header *)root_table; >> + len = header->length; >> + count = (u32)((len - sizeof(struct acpi_table_header)) / size); >> + entry = ACPI_ADD_PTR(u8, header, sizeof(struct acpi_table_header)); >> + >> + for (i = 0; i < count; i++) { >> + u64 address64; >> + >> + if (size == ACPI_RSDT_ENTRY_SIZE) >> + acpi_table = ((acpi_physical_address) >> + (*ACPI_CAST_PTR(u32, entry))); >> + else { >> + *(u64 *)(void *)&address64 = *(u64 *)(void *)entry; >> + acpi_table = (acpi_physical_address) address64; >> + } >> + >> + if (acpi_table) { >> + header = (struct acpi_table_header *)acpi_table; > >> + signature = header->signature; >> + >> + if (!strncmp(signature, "SRAT", 4)) > > if (ACPI_COMPARE_NAME(header->signature, ACPI_SIG_SRAT)) > >> + return header; >> + } >> + entry += size; >> + } >> + return NULL; >> +} >> + >> +#ifdef CONFIG_MEMORY_HOTREMOVE >> +/* >> + * According to ACPI table, filter the immvoable memory regions >> + * and store them in immovable_mem[]. >> + */ >> +void get_immovable_mem(void) >> +{ >> + char *args = (char *)get_cmd_line_ptr(); >> + struct acpi_table_header *table_header; >> + struct acpi_subtable_header *table; >> + struct acpi_srat_mem_affinity *ma; >> + unsigned long table_end; >> + int i = 0; >> + >> + if (!strstr(args, "movable_node") || strstr(args, "acpi=off")) >> + return; >> + >> + table_header = get_acpi_srat_table(); >> + if (!table_header) >> + return; >> + >> + table_end = (unsigned long)table_header + table_header->length; >> + >> + table = (struct acpi_subtable_header *) >> + ((unsigned long)table_header + sizeof(struct acpi_table_srat)); >> + > >> + while (((unsigned long)table) + table->length < table_end) { > > while (((unsigned long)table) + > sizeof(struct acpi_subtable_header) < table_end) { > >> + if (table->type == 1) { > > if (table->type == ACPI_SRAT_TYPE_MEMORY_AFFINITY) { > >> + ma = (struct acpi_srat_mem_affinity *)table; >> + if (!(ma->flags & ACPI_SRAT_MEM_HOT_PLUGGABLE)) { >> + immovable_mem[i].start = ma->base_address; >> + immovable_mem[i].size = ma->length; >> + i++; >> + } >> + >> + if (i >= MAX_NUMNODES*2) >> + break; >> + } >> + table = (struct acpi_subtable_header *) >> + ((unsigned long)table + table->length); >> + } >> + num_immovable_mem = i; >> +} > >Thanks, >Masa > >
