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efi: libstub: Move screen_info handling to common code 

Currently, arm64, RISC-V and LoongArch rely on the fact that struct
screen_info can be accessed directly, due to the fact that the EFI stub
and the core kernel are part of the same image. This will change after a
future patch, so let's ensure that the screen_info handling is able to
deal with this, by adopting the arm32 approach of passing it as a
configuration table. While at it, switch to ACPI reclaim memory to hold
the screen_info data, which is more appropriate for this kind of
allocation.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
This commit is contained in:
Ard Biesheuvel 2022-10-11 17:10:39 +02:00
parent 06064800d9
commit 732ea9db9d
14 changed files with 121 additions and 94 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
arch/arm/include/asm/efi.h
View File

@ -43,9 +43,6 @@ void efi_virtmap_unload(void);
/* arch specific definitions used by the stub code */
struct screen_info *alloc_screen_info(void);
void free_screen_info(struct screen_info *si);
/*
* A reasonable upper bound for the uncompressed kernel size is 32 MBytes,
* so we will reserve that amount of memory. We have no easy way to tell what

31
arch/arm/kernel/efi.c
View File

@ -75,38 +75,13 @@ int __init efi_create_mapping(struct mm_struct *mm, efi_memory_desc_t *md)
return 0;
}
static unsigned long __initdata screen_info_table = EFI_INVALID_TABLE_ADDR;
static unsigned long __initdata cpu_state_table = EFI_INVALID_TABLE_ADDR;
const efi_config_table_type_t efi_arch_tables[] __initconst = {
{LINUX_EFI_ARM_SCREEN_INFO_TABLE_GUID, &screen_info_table},
{LINUX_EFI_ARM_CPU_STATE_TABLE_GUID, &cpu_state_table},
{}
};
static void __init load_screen_info_table(void)
{
struct screen_info *si;
if (screen_info_table != EFI_INVALID_TABLE_ADDR) {
si = early_memremap_ro(screen_info_table, sizeof(*si));
if (!si) {
pr_err("Could not map screen_info config table\n");
return;
}
screen_info = *si;
early_memunmap(si, sizeof(*si));
/* dummycon on ARM needs non-zero values for columns/lines */
screen_info.orig_video_cols = 80;
screen_info.orig_video_lines = 25;
if (memblock_is_map_memory(screen_info.lfb_base))
memblock_mark_nomap(screen_info.lfb_base,
screen_info.lfb_size);
}
}
static void __init load_cpu_state_table(void)
{
if (cpu_state_table != EFI_INVALID_TABLE_ADDR) {
@ -145,7 +120,11 @@ void __init arm_efi_init(void)
{
efi_init();
load_screen_info_table();
if (screen_info.orig_video_isVGA == VIDEO_TYPE_EFI) {
/* dummycon on ARM needs non-zero values for columns/lines */
screen_info.orig_video_cols = 80;
screen_info.orig_video_lines = 25;
}
/* ARM does not permit early mappings to persist across paging_init() */
efi_memmap_unmap();

6
arch/arm64/include/asm/efi.h
View File

@ -84,12 +84,6 @@ static inline unsigned long efi_get_max_initrd_addr(unsigned long image_addr)
return (image_addr & ~(SZ_1G - 1UL)) + (1UL << (VA_BITS_MIN - 1));
}
#define alloc_screen_info(x...) &screen_info
static inline void free_screen_info(struct screen_info *si)
{
}
#define EFI_ALLOC_ALIGN SZ_64K
/*

9
arch/loongarch/include/asm/efi.h
View File

@ -19,15 +19,6 @@ void efifb_setup_from_dmi(struct screen_info *si, const char *opt);
#define EFI_ALLOC_ALIGN SZ_64K
#define EFI_RT_VIRTUAL_OFFSET CSR_DMW0_BASE
static inline struct screen_info *alloc_screen_info(void)
{
return &screen_info;
}
static inline void free_screen_info(struct screen_info *si)
{
}
static inline unsigned long efi_get_max_initrd_addr(unsigned long image_addr)
{
return ULONG_MAX;

24
arch/loongarch/kernel/efi.c
View File

@ -52,6 +52,27 @@ void __init efi_runtime_init(void)
set_bit(EFI_RUNTIME_SERVICES, &efi.flags);
}
unsigned long __initdata screen_info_table = EFI_INVALID_TABLE_ADDR;
static void __init init_screen_info(void)
{
struct screen_info *si;
if (screen_info_table == EFI_INVALID_TABLE_ADDR)
return;
si = early_memremap(screen_info_table, sizeof(*si));
if (!si) {
pr_err("Could not map screen_info config table\n");
return;
}
screen_info = *si;
memset(si, 0, sizeof(*si));
early_memunmap(si, sizeof(*si));
memblock_reserve(screen_info.lfb_base, screen_info.lfb_size);
}
void __init efi_init(void)
{
int size;
@ -80,8 +101,7 @@ void __init efi_init(void)
set_bit(EFI_CONFIG_TABLES, &efi.flags);
if (screen_info.orig_video_isVGA == VIDEO_TYPE_EFI)
memblock_reserve(screen_info.lfb_base, screen_info.lfb_size);
init_screen_info();
if (boot_memmap == EFI_INVALID_TABLE_ADDR)
return;

6
arch/riscv/include/asm/efi.h
View File

@ -31,12 +31,6 @@ static inline unsigned long efi_get_max_initrd_addr(unsigned long image_addr)
return ULONG_MAX;
}
#define alloc_screen_info(x...) (&screen_info)
static inline void free_screen_info(struct screen_info *si)
{
}
void efi_virtmap_load(void);
void efi_virtmap_unload(void);

21
drivers/firmware/efi/efi-init.c
View File

@ -22,6 +22,8 @@
#include <asm/efi.h>
unsigned long __initdata screen_info_table = EFI_INVALID_TABLE_ADDR;
static int __init is_memory(efi_memory_desc_t *md)
{
if (md->attribute & (EFI_MEMORY_WB|EFI_MEMORY_WT|EFI_MEMORY_WC))
@ -55,9 +57,22 @@ extern __weak const efi_config_table_type_t efi_arch_tables[];
static void __init init_screen_info(void)
{
if (screen_info.orig_video_isVGA == VIDEO_TYPE_EFI &&
memblock_is_map_memory(screen_info.lfb_base))
memblock_mark_nomap(screen_info.lfb_base, screen_info.lfb_size);
struct screen_info *si;
if (screen_info_table != EFI_INVALID_TABLE_ADDR) {
si = early_memremap(screen_info_table, sizeof(*si));
if (!si) {
pr_err("Could not map screen_info config table\n");
return;
}
screen_info = *si;
memset(si, 0, sizeof(*si));
early_memunmap(si, sizeof(*si));
if (memblock_is_map_memory(screen_info.lfb_base))
memblock_mark_nomap(screen_info.lfb_base,
screen_info.lfb_size);
}
}
static int __init uefi_init(u64 efi_system_table)

5
drivers/firmware/efi/efi.c
View File

@ -58,6 +58,8 @@ static unsigned long __initdata mem_reserve = EFI_INVALID_TABLE_ADDR;
static unsigned long __initdata rt_prop = EFI_INVALID_TABLE_ADDR;
static unsigned long __initdata initrd = EFI_INVALID_TABLE_ADDR;
extern unsigned long screen_info_table;
struct mm_struct efi_mm = {
.mm_mt = MTREE_INIT_EXT(mm_mt, MM_MT_FLAGS, efi_mm.mmap_lock),
.mm_users = ATOMIC_INIT(2),
@ -546,6 +548,9 @@ static const efi_config_table_type_t common_tables[] __initconst = {
#endif
#ifdef CONFIG_EFI_COCO_SECRET
{LINUX_EFI_COCO_SECRET_AREA_GUID, &efi.coco_secret, "CocoSecret" },
#endif
#ifdef CONFIG_EFI_GENERIC_STUB
{LINUX_EFI_SCREEN_INFO_TABLE_GUID, &screen_info_table },
#endif
{},
};

3
drivers/firmware/efi/libstub/Makefile
View File

@ -81,7 +81,8 @@ lib-$(CONFIG_EFI_PARAMS_FROM_FDT) += fdt.o \
$(obj)/lib-%.o: $(srctree)/lib/%.c FORCE
$(call if_changed_rule,cc_o_c)
lib-$(CONFIG_EFI_GENERIC_STUB) += efi-stub.o string.o intrinsics.o systable.o
lib-$(CONFIG_EFI_GENERIC_STUB) += efi-stub.o string.o intrinsics.o systable.o \
screen_info.o
lib-$(CONFIG_ARM) += arm32-stub.o
lib-$(CONFIG_ARM64) += arm64-stub.o arm64-entry.o

37
drivers/firmware/efi/libstub/arm32-stub.c
View File

@ -76,43 +76,6 @@ void efi_handle_post_ebs_state(void)
&efi_entry_state->sctlr_after_ebs);
}
static efi_guid_t screen_info_guid = LINUX_EFI_ARM_SCREEN_INFO_TABLE_GUID;
struct screen_info *alloc_screen_info(void)
{
struct screen_info *si;
efi_status_t status;
/*
* Unlike on arm64, where we can directly fill out the screen_info
* structure from the stub, we need to allocate a buffer to hold
* its contents while we hand over to the kernel proper from the
* decompressor.
*/
status = efi_bs_call(allocate_pool, EFI_RUNTIME_SERVICES_DATA,
sizeof(*si), (void **)&si);
if (status != EFI_SUCCESS)
return NULL;
status = efi_bs_call(install_configuration_table,
&screen_info_guid, si);
if (status == EFI_SUCCESS)
return si;
efi_bs_call(free_pool, si);
return NULL;
}
void free_screen_info(struct screen_info *si)
{
if (!si)
return;
efi_bs_call(install_configuration_table, &screen_info_guid, NULL);
efi_bs_call(free_pool, si);
}
efi_status_t handle_kernel_image(unsigned long *image_addr,
unsigned long *image_size,
unsigned long *reserve_addr,

9
drivers/firmware/efi/libstub/efi-stub.c
View File

@ -47,6 +47,15 @@
static u64 virtmap_base = EFI_RT_VIRTUAL_BASE;
static bool flat_va_mapping = (EFI_RT_VIRTUAL_OFFSET != 0);
struct screen_info * __weak alloc_screen_info(void)
{
return &screen_info;
}
void __weak free_screen_info(struct screen_info *si)
{
}
static struct screen_info *setup_graphics(void)
{
efi_guid_t gop_proto = EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID;

3
drivers/firmware/efi/libstub/efistub.h
View File

@ -975,4 +975,7 @@ efi_enable_reset_attack_mitigation(void) { }
void efi_retrieve_tpm2_eventlog(void);
struct screen_info *alloc_screen_info(void);
void free_screen_info(struct screen_info *si);
#endif

56
drivers/firmware/efi/libstub/screen_info.c Normal file
View File

@ -0,0 +1,56 @@
// SPDX-License-Identifier: GPL-2.0
#include <linux/efi.h>
#include <asm/efi.h>
#include "efistub.h"
/*
* There are two ways of populating the core kernel's struct screen_info via the stub:
* - using a configuration table, like below, which relies on the EFI init code
* to locate the table and copy the contents;
* - by linking directly to the core kernel's copy of the global symbol.
*
* The latter is preferred because it makes the EFIFB earlycon available very
* early, but it only works if the EFI stub is part of the core kernel image
* itself. The zboot decompressor can only use the configuration table
* approach.
*
* In order to support both methods from the same build of the EFI stub
* library, provide this dummy global definition of struct screen_info. If it
* is required to satisfy a link dependency, it means we need to override the
* __weak alloc and free methods with the ones below, and those will be pulled
* in as well.
*/
struct screen_info screen_info;
static efi_guid_t screen_info_guid = LINUX_EFI_SCREEN_INFO_TABLE_GUID;
struct screen_info *alloc_screen_info(void)
{
struct screen_info *si;
efi_status_t status;
status = efi_bs_call(allocate_pool, EFI_ACPI_RECLAIM_MEMORY,
sizeof(*si), (void **)&si);
if (status != EFI_SUCCESS)
return NULL;
status = efi_bs_call(install_configuration_table,
&screen_info_guid, si);
if (status == EFI_SUCCESS)
return si;
efi_bs_call(free_pool, si);
return NULL;
}
void free_screen_info(struct screen_info *si)
{
if (!si)
return;
efi_bs_call(install_configuration_table, &screen_info_guid, NULL);
efi_bs_call(free_pool, si);
}

2
include/linux/efi.h
View File

@ -403,7 +403,7 @@ void efi_native_runtime_setup(void);
* structure that was populated by the stub based on the GOP protocol instance
* associated with ConOut
*/
#define LINUX_EFI_ARM_SCREEN_INFO_TABLE_GUID EFI_GUID(0xe03fc20a, 0x85dc, 0x406e, 0xb9, 0x0e, 0x4a, 0xb5, 0x02, 0x37, 0x1d, 0x95)
#define LINUX_EFI_SCREEN_INFO_TABLE_GUID EFI_GUID(0xe03fc20a, 0x85dc, 0x406e, 0xb9, 0x0e, 0x4a, 0xb5, 0x02, 0x37, 0x1d, 0x95)
#define LINUX_EFI_ARM_CPU_STATE_TABLE_GUID EFI_GUID(0xef79e4aa, 0x3c3d, 0x4989, 0xb9, 0x02, 0x07, 0xa9, 0x43, 0xe5, 0x50, 0xd2)
#define LINUX_EFI_LOADER_ENTRY_GUID EFI_GUID(0x4a67b082, 0x0a4c, 0x41cf, 0xb6, 0xc7, 0x44, 0x0b, 0x29, 0xbb, 0x8c, 0x4f)
#define LINUX_EFI_RANDOM_SEED_TABLE_GUID EFI_GUID(0x1ce1e5bc, 0x7ceb, 0x42f2, 0x81, 0xe5, 0x8a, 0xad, 0xf1, 0x80, 0xf5, 0x7b)