On Mon, Nov 12, 2018 at 05:46:41PM +0800, Chao Fan wrote: > In order to parse SRAT table and get memory information, RSDP pointer > should be found. In kernel, there are three methods to get RSDP: > EFI condition, BIOS condition and KEXEC condition. The first works > for EFI condition.
"condition"? Also, please explain shortly what all those abbreviations mean: think of a person reading your commit message who doesn't have any clue from ACPI. > Imitate ACPI code and EFI code to dig RSDP pointer from EFI tables. > Process: boot_param->systab->efi_config_table->RSDP. > Based on efi_init(), efi_config_init(), efi_config_parse_tables(). > > Signed-off-by: Chao Fan <[email protected]> > --- > arch/x86/boot/compressed/acpitb.c | 96 +++++++++++++++++++++++++++++++ > 1 file changed, 96 insertions(+) > create mode 100644 arch/x86/boot/compressed/acpitb.c > > diff --git a/arch/x86/boot/compressed/acpitb.c > b/arch/x86/boot/compressed/acpitb.c > new file mode 100644 > index 000000000000..56b54b0e0889 > --- /dev/null > +++ b/arch/x86/boot/compressed/acpitb.c > @@ -0,0 +1,96 @@ > +// SPDX-License-Identifier: GPL-2.0 > +#define BOOT_CTYPE_H > +#include "misc.h" > +#include "error.h" > + > +#include <linux/efi.h> > +#include <asm/efi.h> > +#include <linux/numa.h> > +#include <linux/acpi.h> > + > +/* Search EFI table for RSDP table. */ > +static void efi_get_rsdp_addr(acpi_physical_address *rsdp_addr) This is just silly: the function returns void and has a single parameter which is an *output* parameter?! Why isn't the signature static acpi_physical_address *efi_get_rsdp_addr(void) instead? > +{ > +#ifdef CONFIG_EFI > + efi_system_table_t *systab; > + bool efi_64 = false; You're setting it below already, why here too? > + void *config_tables; > + struct efi_info *e; > + char *sig; > + int size; > + int i; > + > + e = &boot_params->efi_info; > + sig = (char *)&e->efi_loader_signature; > + > + if (!strncmp(sig, EFI64_LOADER_SIGNATURE, 4)) > + efi_64 = true; > + else if (!strncmp(sig, EFI32_LOADER_SIGNATURE, 4)) > + efi_64 = false; > + else { > + debug_putstr("Wrong EFI loader signature.\n"); > + return; > + } > + > + /* Get systab from boot params. Based on efi_init(). */ > +#ifdef CONFIG_X86_64 > + systab = (efi_system_table_t *)( > + e->efi_systab | ((__u64)e->efi_systab_hi<<32)); No ugly line breaks with open braces trailing like that, pls - just let it stick out. > +#else > + if (e->efi_systab_hi || e->efi_memmap_hi) { > + debug_putstr("Table located above 4GB. EFI should be > disabled.\n"); You need to say here what really happens here: debug_putstr("Error getting RSDP address: EFI system table located above 4GB.\n"); The same below. > + return; > + } > + systab = (efi_system_table_t *)e->efi_systab; > +#endif > + > + if (!systab) > + return; > + > + /* > + * Get EFI tables from systab. Based on efi_config_init() and > + * efi_config_parse_tables(). Only dig out the config_table. > + */ > + size = efi_64 ? sizeof(efi_config_table_64_t) : > + sizeof(efi_config_table_32_t); > + > + for (i = 0; i < systab->nr_tables; i++) { > + efi_guid_t guid; > + unsigned long table; Put the void *config_tables declaration here. > + > + config_tables = (void *)(systab->tables + size * i); > + if (efi_64) { > + efi_config_table_64_t *tmp_table; > + > + tmp_table = (efi_config_table_64_t *)config_tables; > + guid = tmp_table->guid; > + table = tmp_table->table; > +#ifndef CONFIG_64BIT Above you have CONFIG_X86_64, here CONFIG_64BIT. Please use one only. Also, use IS_ENABLED() instead. > + if (table >> 32) { > + debug_putstr("Table located above 4G. EFI > should be disabled.\n"); > + return; > + } > +#endif > + } else { > + efi_config_table_32_t *tmp_table; > + > + tmp_table = (efi_config_table_32_t *)config_tables; > + guid = tmp_table->guid; > + table = tmp_table->table; > + } > + > + /* > + * Get RSDP from EFI tables. > + * If ACPI20 table found, use it. > + * If ACPI20 table not found, but ACPI table found, > + * use the ACPI table. > + */ That comment is the opposite of what the code does. Also, why is that comment needed at all? If anything, it should say *why* ACPI_TABLE_GUID is preferred and then the fallback to ACPI_20_TABLE_GUID is done - not *what* it does. That's easily visible in the code. Thx. -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the reply.
