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Subject[PATCH v12 4/5] x86/boot: Parse SRAT table from RSDP and store immovable memory
Date
To fix the conflict between KASLR and memory-hotremove, SRAT table
should be parsed by RSDP pointer, then find the immovable
memory regions and store them in an array called immovable_mem[].
The array called immovable_mem[] will extern to KASLR, then
KASLR will avoid to extract kernel to these regions.

Add 'CONFIG_EARLY_PARSE_RSDP' which depends on RANDOMIZE_BASE &&
MEMORY_HOTREMOVE, cause only when both KASLR and memory-hotremove
are enabled, RSDP needs to be parsed in compressed period.

Signed-off-by: Chao Fan <fanc.fnst@cn.fujitsu.com>
---
arch/x86/Kconfig | 10 +++
arch/x86/boot/compressed/Makefile | 2 +
arch/x86/boot/compressed/acpitb.c | 125 ++++++++++++++++++++++++++++++
arch/x86/boot/compressed/kaslr.c | 4 -
arch/x86/boot/compressed/misc.h | 20 +++++
5 files changed, 157 insertions(+), 4 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index a29d49ef4d56..bc775968557b 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2146,6 +2146,16 @@ config X86_NEED_RELOCS
def_bool y
depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)

+config CONFIG_EARLY_PARSE_RSDP
+ bool "Parse RSDP pointer on compressed period for KASLR"
+ def_bool n
+ depends on RANDOMIZE_BASE && MEMORY_HOTREMOVE
+ help
+ This option parses RSDP pointer in compressed period. Works
+ for KASLR to get memory information by SRAT table and choose
+ immovable memory to extract kernel.
+ Say Y if you want to use both KASLR and memory-hotremove.
+
config PHYSICAL_ALIGN
hex "Alignment value to which kernel should be aligned"
default "0x200000"
diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index 466f66c8a7f8..4cbfb58bf083 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -84,6 +84,8 @@ ifdef CONFIG_X86_64
vmlinux-objs-y += $(obj)/pgtable_64.o
endif

+vmlinux-objs-$(CONFIG_EARLY_PARSE_RSDP) += $(obj)/acpitb.o
+
$(obj)/eboot.o: KBUILD_CFLAGS += -fshort-wchar -mno-red-zone

vmlinux-objs-$(CONFIG_EFI_STUB) += $(obj)/eboot.o $(obj)/efi_stub_$(BITS).o \
diff --git a/arch/x86/boot/compressed/acpitb.c b/arch/x86/boot/compressed/acpitb.c
index 82d27c4b8978..023b33d0cd3b 100644
--- a/arch/x86/boot/compressed/acpitb.c
+++ b/arch/x86/boot/compressed/acpitb.c
@@ -195,3 +195,128 @@ static acpi_physical_address bios_get_rsdp_addr(void)
return (acpi_physical_address)address;
}
}
+
+/* Used to determine RSDP table, based on acpi_os_get_root_pointer(). */
+static acpi_physical_address get_rsdp_addr(void)
+{
+ acpi_physical_address pa = 0;
+
+ pa = get_acpi_rsdp();
+
+ if (!pa)
+ pa = efi_get_rsdp_addr();
+
+ if (!pa)
+ pa = bios_get_rsdp_addr();
+
+ return pa;
+}
+
+/* Compute SRAT table from RSDP. */
+static struct acpi_table_header *get_acpi_srat_table(void)
+{
+ acpi_physical_address acpi_table;
+ acpi_physical_address root_table;
+ struct acpi_table_header *header;
+ struct acpi_table_rsdp *rsdp;
+ int num_entries;
+ char arg[10];
+ u8 *entry;
+ u32 size;
+ u32 len;
+
+ rsdp = (struct acpi_table_rsdp *)get_rsdp_addr();
+ if (!rsdp)
+ return NULL;
+
+ /* Get RSDT or XSDT from RSDP. */
+ if (!(cmdline_find_option("acpi", arg, sizeof(arg)) == 4 &&
+ !strncmp(arg, "rsdt", 4)) &&
+ 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;
+ if (!header)
+ return NULL;
+
+ len = header->length;
+ num_entries = (u32)((len - sizeof(struct acpi_table_header)) / size);
+ if (num_entries > MAX_ACPI_SIG)
+ return NULL;
+
+ entry = ACPI_ADD_PTR(u8, header, sizeof(struct acpi_table_header));
+
+ while (num_entries--) {
+ 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;
+
+ if (ACPI_COMPARE_NAME(header->signature, ACPI_SIG_SRAT))
+ return header;
+ }
+ entry += size;
+ }
+ return NULL;
+}
+
+/*
+ * According to ACPI table, filter the immovable memory regions
+ * and store them in immovable_mem[].
+ */
+void get_immovable_mem(void)
+{
+ struct acpi_table_header *table_header;
+ struct acpi_subtable_header *table;
+ struct acpi_srat_mem_affinity *ma;
+ unsigned long table_end;
+ char arg[10];
+ int i = 0;
+
+ if (cmdline_find_option("acpi", arg, sizeof(arg)) == 3 &&
+ !strncmp(arg, "off", 3))
+ 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) +
+ sizeof(struct acpi_subtable_header) < table_end) {
+ 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) {
+ debug_putstr("Too many immovable memory regions, aborting.\n");
+ return;
+ }
+ }
+ table = (struct acpi_subtable_header *)
+ ((unsigned long)table + table->length);
+ }
+ num_immovable_mem = i;
+}
diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
index 9ed9709d9947..b251572e77af 100644
--- a/arch/x86/boot/compressed/kaslr.c
+++ b/arch/x86/boot/compressed/kaslr.c
@@ -87,10 +87,6 @@ static unsigned long get_boot_seed(void)
#define KASLR_COMPRESSED_BOOT
#include "../../lib/kaslr.c"

-struct mem_vector {
- unsigned long long start;
- unsigned long long size;
-};

/* Only supporting at most 4 unusable memmap regions with kaslr */
#define MAX_MEMMAP_REGIONS 4
diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
index 809c31effa4b..d94e2a419c13 100644
--- a/arch/x86/boot/compressed/misc.h
+++ b/arch/x86/boot/compressed/misc.h
@@ -77,6 +77,11 @@ void choose_random_location(unsigned long input,
unsigned long *output,
unsigned long output_size,
unsigned long *virt_addr);
+struct mem_vector {
+ unsigned long long start;
+ unsigned long long size;
+};
+
/* cpuflags.c */
bool has_cpuflag(int flag);
#else
@@ -118,5 +123,20 @@ void set_sev_encryption_mask(void);
#endif

/* acpitb.c */
+#ifdef CONFIG_RANDOMIZE_BASE
+/* Store the amount of immovable memory regions */
+int num_immovable_mem;
+#endif
+
+#ifdef CONFIG_EARLY_PARSE_RSDP
+void get_immovable_mem(void);
+/* There are 72 kinds of ACPI_SIG in head file of ACPI. */
+#define MAX_ACPI_SIG 72
+#else
+static void get_immovable_mem(void)
+{
+}
+#endif
+
#define BOOT_STRING
extern int kstrtoull(const char *s, unsigned int base, unsigned long long *res);
--
2.19.1


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