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x86/compressed/acpi: Move EFI kexec handling into common code

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Future patches for SEV-SNP-validated CPUID will also require early
parsing of the EFI configuration. Incrementally move the related code
into a set of helpers that can be re-used for that purpose.

In this instance, the current acpi.c kexec handling is mainly used to
get the alternative EFI config table address provided by kexec via a
setup_data entry of type SETUP_EFI. If not present, the code then falls
back to normal EFI config table address provided by EFI system table.
This would need to be done by all call-sites attempting to access the
EFI config table, so just have efi_get_conf_table() handle that
automatically.

Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220307213356.2797205-29-brijesh.singh@amd.com
This commit is contained in:
Michael Roth 2022-02-24 10:56:08 -06:00 committed by Borislav Petkov
parent dee602dd5d
commit 824f377831
2 changed files with 45 additions and 60 deletions
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59
arch/x86/boot/compressed/acpi.c
View File

@ -47,57 +47,6 @@ __efi_get_rsdp_addr(unsigned long cfg_tbl_pa, unsigned int cfg_tbl_len)
return 0;
}
/* EFI/kexec support is 64-bit only. */
#ifdef CONFIG_X86_64
static struct efi_setup_data *get_kexec_setup_data_addr(void)
{
struct setup_data *data;
u64 pa_data;
pa_data = boot_params->hdr.setup_data;
while (pa_data) {
data = (struct setup_data *)pa_data;
if (data->type == SETUP_EFI)
return (struct efi_setup_data *)(pa_data + sizeof(struct setup_data));
pa_data = data->next;
}
return NULL;
}
static acpi_physical_address kexec_get_rsdp_addr(void)
{
efi_system_table_64_t *systab;
struct efi_setup_data *esd;
struct efi_info *ei;
enum efi_type et;
esd = (struct efi_setup_data *)get_kexec_setup_data_addr();
if (!esd)
return 0;
if (!esd->tables) {
debug_putstr("Wrong kexec SETUP_EFI data.\n");
return 0;
}
et = efi_get_type(boot_params);
if (et != EFI_TYPE_64) {
debug_putstr("Unexpected kexec EFI environment (expected 64-bit EFI).\n");
return 0;
}
/* Get systab from boot params. */
systab = (efi_system_table_64_t *)efi_get_system_table(boot_params);
if (!systab)
error("EFI system table not found in kexec boot_params.");
return __efi_get_rsdp_addr((unsigned long)esd->tables, systab->nr_tables);
}
#else
static acpi_physical_address kexec_get_rsdp_addr(void) { return 0; }
#endif /* CONFIG_X86_64 */
static acpi_physical_address efi_get_rsdp_addr(void)
{
#ifdef CONFIG_EFI
@ -210,14 +159,6 @@ acpi_physical_address get_rsdp_addr(void)
pa = boot_params->acpi_rsdp_addr;
/*
* Try to get EFI data from setup_data. This can happen when we're a
* kexec'ed kernel and kexec(1) has passed all the required EFI info to
* us.
*/
if (!pa)
pa = kexec_get_rsdp_addr();
if (!pa)
pa = efi_get_rsdp_addr();

46
arch/x86/boot/compressed/efi.c
View File

@ -78,6 +78,46 @@ unsigned long efi_get_system_table(struct boot_params *bp)
return sys_tbl_pa;
}
/*
* EFI config table address changes to virtual address after boot, which may
* not be accessible for the kexec'd kernel. To address this, kexec provides
* the initial physical address via a struct setup_data entry, which is
* checked for here, along with some sanity checks.
*/
static struct efi_setup_data *get_kexec_setup_data(struct boot_params *bp,
enum efi_type et)
{
#ifdef CONFIG_X86_64
struct efi_setup_data *esd = NULL;
struct setup_data *data;
u64 pa_data;
pa_data = bp->hdr.setup_data;
while (pa_data) {
data = (struct setup_data *)pa_data;
if (data->type == SETUP_EFI) {
esd = (struct efi_setup_data *)(pa_data + sizeof(struct setup_data));
break;
}
pa_data = data->next;
}
/*
* Original ACPI code falls back to attempting normal EFI boot in these
* cases, so maintain existing behavior by indicating non-kexec
* environment to the caller, but print them for debugging.
*/
if (esd && !esd->tables) {
debug_putstr("kexec EFI environment missing valid configuration table.\n");
return NULL;
}
return esd;
#endif
return NULL;
}
/**
* efi_get_conf_table - Given a pointer to boot_params, locate and return the physical
* address of EFI configuration table.
@ -106,8 +146,12 @@ int efi_get_conf_table(struct boot_params *bp, unsigned long *cfg_tbl_pa,
et = efi_get_type(bp);
if (et == EFI_TYPE_64) {
efi_system_table_64_t *stbl = (efi_system_table_64_t *)sys_tbl_pa;
struct efi_setup_data *esd;
*cfg_tbl_pa = stbl->tables;
/* kexec provides an alternative EFI conf table, check for it. */
esd = get_kexec_setup_data(bp, et);
*cfg_tbl_pa = esd ? esd->tables : stbl->tables;
*cfg_tbl_len = stbl->nr_tables;
} else if (et == EFI_TYPE_32) {
efi_system_table_32_t *stbl = (efi_system_table_32_t *)sys_tbl_pa;