Re: [PATCH v15 5/6] x86/boot: Parse SRAT address from RSDP and store immovable memory

Chao Fan
2019-01-21T09:35:05Z

On Wed, Jan 16, 2019 at 12:01:58PM +0100, Borislav Petkov wrote:
>On Mon, Jan 07, 2019 at 11:22:42AM +0800, Chao Fan wrote:
[...]
>> +
>> +/* Determine RSDP, based on acpi_os_get_root_pointer(). */
>> +static acpi_physical_address get_rsdp_addr(void)
>> +{
>> + acpi_physical_address pa;
>> +
>> + pa = get_acpi_rsdp();
>> +
>> + if (!pa)
>> + pa = efi_get_rsdp_addr();
>> +
>> + if (!pa)
>> + pa = bios_get_rsdp_addr();
>> +
>> + return pa;
>> +}

Hi Boris,

Talking in Kairui's thread may mislead you, let me clarify:
I mean I am going to change get_rsdp_addr(). Since I see ACPI code:

>acpi_physical_address __init acpi_os_get_root_pointer(void)
>{
> acpi_physical_address pa;
>
>#ifdef CONFIG_KEXEC
> if (acpi_rsdp)
> return acpi_rsdp;
>#endif
> pa = acpi_arch_get_root_pointer();
> if (pa)
> return pa;

So we need to parse boot_params->acpi_rsdp_addr also between KEXEC and
EFI:

static acpi_physical_address get_rsdp_addr(void)
{
acpi_physical_address pa;

pa = get_acpi_rsdp();

if (!pa)
/* This line will be added in next version.*/
pa = boot_params->acpi_rsdp_addr;

if (!pa)
pa = efi_get_rsdp_addr();

if (!pa)
pa = bios_get_rsdp_addr();

/* If no acpi_rsdp_addr found in boot_params, fill in it here. */

return pa;
}

Then you said I shall fill the boot_params->acpi_rsdp_addr, so in my
understanding, if there is no acpi_rsdp_addr found in boot_params,
we can parse RSDP by EFI/BIOS then fill it, other wise if it's found
int boot_params, we need't to fill it.

Thanks,
Chao Fan

>> +
>> +/* Compute SRAT address 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;
>> + u32 num_entries;
>> + char arg[10];
>> + u8 *entry;
>> + u32 size;
>> + u32 len;
>> +
>> + rsdp = (struct acpi_table_rsdp *)(long)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.*/
>
>This comment is wrong here - should be above.
>
>> + if (!root_table)
>> + return NULL;
>
><---- newline here.
>
>> + header = (struct acpi_table_header *)(long)root_table;
>> +
>> + len = header->length;
>> + if (len < sizeof(struct acpi_table_header) + size)
>> + return NULL;
>> +
>> + num_entries = (u32)((len - sizeof(struct acpi_table_header)) / size);
>> + 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_CAST_PTR(u32, entry);
>> + else {
>> + address64 = *(u64 *)entry;
>> + acpi_table = address64;
>
>The same thing as in the previous patch - get rid of address64.
>
>> + }
>> +
>> + if (acpi_table) {
>> + header = (struct acpi_table_header *)(long)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;
>> + char arg[MAX_ACPI_ARG_LENGTH];
>> + unsigned long table_end;
>> + 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);
>
>That's a lot of unnecessary casting AFAICT. You can return an unsigned
>long from get_acpi_srat_table() and get rid of all that casting here.
>
>
>> + }
>> + 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 a1d5918765f3..b49748366a5b 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
>> @@ -116,3 +121,17 @@ static inline void console_init(void)
>> void set_sev_encryption_mask(void);
>>
>> #endif
>> +
>> +/* acpi.c */
>> +#ifdef CONFIG_RANDOMIZE_BASE
>> +/* Amount of immovable memory regions */
>> +int num_immovable_mem;
>> +#endif
>> +
>> +#ifdef CONFIG_EARLY_SRAT_PARSE
>> +void get_immovable_mem(void);
>> +#else
>> +static void get_immovable_mem(void)
>> +{
>> +}
>
>Put those on a single line:
>
>static void get_immovable_mem(void) {}
>
>> +#endif
>> --
>> 2.20.1
>>
>>
>>
>
>--
>Regards/Gruss,
> Boris.
>
>Good mailing practices for 400: avoid top-posting and trim the reply.
>
>