From mboxrd@z Thu Jan 1 00:00:00 1970 From: Masayoshi Mizuma Subject: Re: [PATCH v8 1/3] x86/boot: Add acpitb.c to parse acpi tables Date: Mon, 15 Oct 2018 16:26:09 -0400 Message-ID: <20181015202609.gs6jownxbevs4vzr@gabell> References: <20181010084119.17539-1-fanc.fnst@cn.fujitsu.com> <20181010084119.17539-2-fanc.fnst@cn.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20181010084119.17539-2-fanc.fnst@cn.fujitsu.com> Sender: linux-kernel-owner@vger.kernel.org To: Chao Fan Cc: linux-kernel@vger.kernel.org, x86@kernel.org, linux-efi@vger.kernel.org, linux-acpi@vger.kernel.org, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, keescook@chromium.org, bhe@redhat.com, rjw@rjwysocki.net, lenb@kernel.org, ard.biesheuvel@linaro.org, indou.takao@jp.fujitsu.com, caoj.fnst@cn.fujitsu.com List-Id: linux-acpi@vger.kernel.org Hi Chao, Let me add some suggestions. 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 > --- > 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