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Date: Wed, 16 Jan 2019 15:28:52 +0800
From: Kairui Song <kasong@...hat.com>
To: Chao Fan <fanc.fnst@...fujitsu.com>
Cc: linux-kernel@...r.kernel.org, x86@...nel.org,
Borislav Petkov <bp@...en8.de>, tglx@...utronix.de,
mingo@...hat.com, hpa@...or.com, keescook@...omium.org,
Baoquan He <bhe@...hat.com>, msys.mizuma@...il.com,
indou.takao@...fujitsu.com, caoj.fnst@...fujitsu.com
Subject: Re: [PATCH v15 5/6] x86/boot: Parse SRAT address from RSDP and store
immovable memory
On Mon, Jan 7, 2019 at 11:24 AM Chao Fan <fanc.fnst@...fujitsu.com> 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;
> +}
acpi_rsdp might be provided by boot_params.acpi_rsdp_addr too,
it's introduced in ae7e1238e68f2a for Xen PVH guest and later move to
boot_params in e6e094e053af,
kexec could use it to pass RSDP to second kernel as well. Please check
it as well make sure it always works.
> +
> +/* 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.*/
> + if (!root_table)
> + return NULL;
> + 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;
> + }
> +
> + 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);
> + }
> + 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)
> +{
> +}
> +#endif
> --
> 2.20.1
>
>
>
--
Best Regards,
Kairui Song
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