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Date: Fri, 30 Nov 2018 09:24:54 +0800
From: Chao Fan <fanc.fnst@...fujitsu.com>
To: Masayoshi Mizuma <msys.mizuma@...il.com>
CC: <linux-kernel@...r.kernel.org>, <x86@...nel.org>, <bp@...en8.de>,
<tglx@...utronix.de>, <mingo@...hat.com>, <hpa@...or.com>,
<keescook@...omium.org>, <bhe@...hat.com>,
<indou.takao@...fujitsu.com>, <caoj.fnst@...fujitsu.com>
Subject: Re: [PATCH v12 4/5] x86/boot: Parse SRAT table from RSDP and store
immovable memory
On Thu, Nov 29, 2018 at 12:55:21PM -0500, Masayoshi Mizuma wrote:
>On Thu, Nov 29, 2018 at 04:16:30PM +0800, Chao Fan wrote:
>> 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@...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
>
>config EARLY_PARSE_RSDP
>
>> + bool "Parse RSDP pointer on compressed period for KASLR"
>> + def_bool n
>
>Should be def_bool y?
I will change it to y.
>It is better to enable EARLY_PARSE_RSDP by default if
>RANDOMIZE_BASE and MEMORY_HOTREMOVE are enabled.
>
>> + 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;
>
>I think this check isn't needed...
>
>> +
>> + 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
>
>The 72 isn't the specification of ACPI, right? So the number
Yes, it's from ACPI code, include/acpi/actbl*h.
Boris said there should be a check for the num_entries,
I didn't get a good idea, so I use the max number to check it.
So do you have some advice?
Thanks,
Chao Fan
>of SIG may increase and decrease in the future.
>This macro and the check I commented above isn't needed...
>
>Thanks,
>Masa
>
>> +#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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