Re: [PATCH 3/6] ACPI: Store valid ACPI tables passed via early initrd in reserved memblock areas

[H. Peter Anvin]

I think you got an explicit NAK for this being default y.

Thomas Renninger <trenn@xxxxxxx> wrote:

>A later patch will compare them with ACPI tables that get loaded at
>boot or
>runtime and if criteria match, a stored one is loaded.
>
>Signed-off-by: Thomas Renninger <trenn@xxxxxxx>
>---
> arch/x86/kernel/setup.c |    2 +
> drivers/acpi/Kconfig    |    9 ++++
>drivers/acpi/osl.c      |  122
>+++++++++++++++++++++++++++++++++++++++++++++++
> include/linux/acpi.h    |    8 +++
> 4 files changed, 141 insertions(+), 0 deletions(-)
>
>diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
>index f4b9b80..764e543 100644
>--- a/arch/x86/kernel/setup.c
>+++ b/arch/x86/kernel/setup.c
>@@ -941,6 +941,8 @@ void __init setup_arch(char **cmdline_p)
> 
> 	reserve_initrd();
> 
>+	acpi_initrd_override((void *)initrd_start, initrd_end -
>initrd_start);
>+
> 	reserve_crashkernel();
> 
> 	vsmp_init();
>diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
>index 8099895..a508f77 100644
>--- a/drivers/acpi/Kconfig
>+++ b/drivers/acpi/Kconfig
>@@ -261,6 +261,15 @@ config ACPI_CUSTOM_DSDT
> 	bool
> 	default ACPI_CUSTOM_DSDT_FILE != ""
> 
>+config ACPI_INITRD_TABLE_OVERRIDE
>+	bool
>+	default y
>+	help
>+	  This option provides functionality to override arbitrary ACPI
>tables
>+	  via initrd. No functional change if no ACPI tables are passed via
>+	  initrd, therefore it's safe to say Y.
>+	  See Documentation/acpi/initrd_table_override.txt for details
>+
> config ACPI_BLACKLIST_YEAR
> 	int "Disable ACPI for systems before Jan 1st this year" if X86_32
> 	default 0
>diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
>index 9eaf708..b20b079 100644
>--- a/drivers/acpi/osl.c
>+++ b/drivers/acpi/osl.c
>@@ -534,6 +534,128 @@ acpi_os_predefined_override(const struct
>acpi_predefined_names *init_val,
> 	return AE_OK;
> }
> 
>+#ifdef CONFIG_ACPI_INITRD_TABLE_OVERRIDE
>+#include <linux/earlycpio.h>
>+#include <linux/memblock.h>
>+
>+static u64 acpi_tables_addr;
>+static int all_tables_size;
>+
>+/* Copied from acpica/tbutils.c:acpi_tb_checksum() */
>+u8 __init acpi_table_checksum(u8 *buffer, u32 length)
>+{
>+	u8 sum = 0;
>+	u8 *end = buffer + length;
>+
>+	while (buffer < end)
>+		sum = (u8) (sum + *(buffer++));
>+	return sum;
>+}
>+
>+/* All but ACPI_SIG_RSDP and ACPI_SIG_FACS: */
>+static const char * const table_sigs[] = {
>+	ACPI_SIG_BERT, ACPI_SIG_CPEP, ACPI_SIG_ECDT, ACPI_SIG_EINJ,
>+	ACPI_SIG_ERST, ACPI_SIG_HEST, ACPI_SIG_MADT, ACPI_SIG_MSCT,
>+	ACPI_SIG_SBST, ACPI_SIG_SLIT, ACPI_SIG_SRAT, ACPI_SIG_ASF,
>+	ACPI_SIG_BOOT, ACPI_SIG_DBGP, ACPI_SIG_DMAR, ACPI_SIG_HPET,
>+	ACPI_SIG_IBFT, ACPI_SIG_IVRS, ACPI_SIG_MCFG, ACPI_SIG_MCHI,
>+	ACPI_SIG_SLIC, ACPI_SIG_SPCR, ACPI_SIG_SPMI, ACPI_SIG_TCPA,
>+	ACPI_SIG_UEFI, ACPI_SIG_WAET, ACPI_SIG_WDAT, ACPI_SIG_WDDT,
>+	ACPI_SIG_WDRT, ACPI_SIG_DSDT, ACPI_SIG_FADT, ACPI_SIG_PSDT,
>+	ACPI_SIG_RSDT, ACPI_SIG_XSDT, ACPI_SIG_SSDT, NULL };
>+
>+/* Non-fatal errors: Affected tables/files are ignored */
>+#define INVALID_TABLE(x, path, name)					\
>+	{ pr_err("ACPI OVERRIDE: " x " [%s%s]\n", path, name); continue; }
>+
>+#define ACPI_HEADER_SIZE sizeof(struct acpi_table_header)
>+
>+/* Must not increase 10 or needs code modification below */
>+#define ACPI_OVERRIDE_TABLES 10
>+
>+void __init acpi_initrd_override(void *data, size_t size)
>+{
>+	int sig, no, table_nr = 0, total_offset = 0;
>+	long offset = 0;
>+	struct acpi_table_header *table;
>+	char cpio_path[32] = "kernel/firmware/acpi/";
>+	struct cpio_data file;
>+	struct cpio_data early_initrd_files[ACPI_OVERRIDE_TABLES];
>+	char *p;
>+
>+	if (data == NULL || size == 0)
>+		return;
>+
>+	for (no = 0; no < ACPI_OVERRIDE_TABLES; no++) {
>+		file = find_cpio_data(cpio_path, data, size, &offset);
>+		if (!file.data)
>+			break;
>+
>+		data += offset;
>+		size -= offset;
>+
>+		if (file.size < sizeof(struct acpi_table_header))
>+			INVALID_TABLE("Table smaller than ACPI header",
>+				      cpio_path, file.name);
>+
>+		table = file.data;
>+
>+		for (sig = 0; table_sigs[sig]; sig++)
>+			if (!memcmp(table->signature, table_sigs[sig], 4))
>+				break;
>+
>+		if (!table_sigs[sig])
>+			INVALID_TABLE("Unknown signature",
>+				      cpio_path, file.name);
>+		if (file.size != table->length)
>+			INVALID_TABLE("File length does not match table length",
>+				      cpio_path, file.name);
>+		if (acpi_table_checksum(file.data, table->length))
>+			INVALID_TABLE("Bad table checksum",
>+				      cpio_path, file.name);
>+
>+		pr_info("%4.4s ACPI table found in initrd [%s%s][0x%x]\n",
>+			table->signature, cpio_path, file.name, table->length);
>+
>+		all_tables_size += table->length;
>+		early_initrd_files[table_nr].data = file.data;
>+		early_initrd_files[table_nr].size = file.size;
>+		table_nr++;
>+	}
>+	if (table_nr == 0)
>+		return;
>+
>+	acpi_tables_addr =
>+		memblock_find_in_range(0, max_low_pfn_mapped << PAGE_SHIFT,
>+				       all_tables_size, PAGE_SIZE);
>+	if (!acpi_tables_addr) {
>+		WARN_ON(1);
>+		return;
>+	}
>+	/*
>+	 * Only calling e820_add_reserve does not work and the
>+	 * tables are invalid (memory got used) later.
>+	 * memblock_reserve works as expected and the tables won't get
>modified.
>+	 * But it's not enough on X86 because ioremap will
>+	 * complain later (used by acpi_os_map_memory) that the pages
>+	 * that should get mapped are not marked "reserved".
>+	 * Both memblock_reserve and e820_add_region (via
>arch_reserve_mem_area)
>+	 * works fine.
>+	 */
>+	memblock_reserve(acpi_tables_addr, acpi_tables_addr +
>all_tables_size);
>+	arch_reserve_mem_area(acpi_tables_addr, all_tables_size);
>+
>+	p = early_ioremap(acpi_tables_addr, all_tables_size);
>+
>+	for (no = 0; no < table_nr; no++) {
>+		memcpy(p + total_offset, early_initrd_files[no].data,
>+		       early_initrd_files[no].size);
>+		total_offset += early_initrd_files[no].size;
>+	}
>+	early_iounmap(p, all_tables_size);
>+}
>+#endif /* CONFIG_ACPI_INITRD_TABLE_OVERRIDE */
>+
> acpi_status
> acpi_os_table_override(struct acpi_table_header * existing_table,
> 		       struct acpi_table_header ** new_table)
>diff --git a/include/linux/acpi.h b/include/linux/acpi.h
>index bf6a0ad..ee81cdc 100644
>--- a/include/linux/acpi.h
>+++ b/include/linux/acpi.h
>@@ -76,6 +76,14 @@ typedef int (*acpi_table_handler) (struct
>acpi_table_header *table);
> 
>typedef int (*acpi_table_entry_handler) (struct acpi_subtable_header
>*header, const unsigned long end);
> 
>+#ifdef CONFIG_ACPI_INITRD_TABLE_OVERRIDE
>+void acpi_initrd_override(void *data, size_t size);
>+#else
>+static inline void acpi_initrd_override(void *data, size_t size)
>+{
>+}
>+#endif
>+
> char * __acpi_map_table (unsigned long phys_addr, unsigned long size);
> void __acpi_unmap_table(char *map, unsigned long size);
> int early_acpi_boot_init(void);

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