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Subject[PATCH 17/25] efi/libstub/x86: drop __efi_early() export and efi_config struct
Date
The various pointers we stash in the efi_config struct which we
retrieve using __efi_early() are simply copies of the ones in
the EFI system table, which we have started accessing directly
in the previous patch. So drop all the __efi_early() related
plumbing, as well as all the assembly code dealing with efi_config,
which allows us to move the PE/COFF entry point to C code as well.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
arch/x86/boot/compressed/eboot.c | 82 +++++++++++-------------------
arch/x86/boot/compressed/head_32.S | 58 +--------------------
arch/x86/boot/compressed/head_64.S | 74 +++++----------------------
arch/x86/include/asm/efi.h | 38 ++++----------
4 files changed, 54 insertions(+), 198 deletions(-)

diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
index 5fb12827bdc2..2a7c6d58cc56 100644
--- a/arch/x86/boot/compressed/eboot.c
+++ b/arch/x86/boot/compressed/eboot.c
@@ -19,32 +19,17 @@
#include "eboot.h"

static efi_system_table_t *sys_table;
-
-static struct efi_config *efi_early;
-
-__pure const struct efi_config *__efi_early(void)
-{
- return efi_early;
-}
+static bool efi_is64 = IS_ENABLED(CONFIG_X86_64);

__pure efi_system_table_t *efi_system_table(void)
{
return sys_table;
}

-#define BOOT_SERVICES(bits) \
-static void setup_boot_services##bits(struct efi_config *c) \
-{ \
- efi_system_table_##bits##_t *table; \
- \
- table = (typeof(table))sys_table; \
- \
- c->runtime_services = table->runtime; \
- c->boot_services = table->boottime; \
- c->text_output = table->con_out; \
+__pure bool efi_is_64bit(void)
+{
+ return efi_is64;
}
-BOOT_SERVICES(32);
-BOOT_SERVICES(64);

static efi_status_t
preserve_pci_rom_image(efi_pci_io_protocol_t *pci, struct pci_setup_rom **__rom)
@@ -367,21 +352,24 @@ void setup_graphics(struct boot_params *boot_params)
}
}

+void startup_32(struct boot_params *boot_params);
+
+void __noreturn efi_stub_entry(efi_handle_t handle,
+ efi_system_table_t *sys_table_arg,
+ struct boot_params *boot_params);
+
/*
* Because the x86 boot code expects to be passed a boot_params we
* need to create one ourselves (usually the bootloader would create
* one for us).
- *
- * The caller is responsible for filling out ->code32_start in the
- * returned boot_params.
*/
-struct boot_params *make_boot_params(struct efi_config *c)
+efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
+ efi_system_table_t *sys_table_arg)
{
struct boot_params *boot_params;
struct apm_bios_info *bi;
struct setup_header *hdr;
efi_loaded_image_t *image;
- void *handle;
efi_guid_t proto = LOADED_IMAGE_PROTOCOL_GUID;
int options_size = 0;
efi_status_t status;
@@ -389,31 +377,24 @@ struct boot_params *make_boot_params(struct efi_config *c)
unsigned long ramdisk_addr;
unsigned long ramdisk_size;

- efi_early = c;
- sys_table = (efi_system_table_t *)(unsigned long)efi_early->table;
- handle = (void *)(unsigned long)efi_early->image_handle;
+ sys_table = sys_table_arg;

/* Check if we were booted by the EFI firmware */
if (sys_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
- return NULL;
-
- if (efi_is_64bit())
- setup_boot_services64(efi_early);
- else
- setup_boot_services32(efi_early);
+ return EFI_INVALID_PARAMETER;

status = efi_call_early(handle_protocol, handle,
&proto, (void *)&image);
if (status != EFI_SUCCESS) {
efi_printk(sys_table, "Failed to get handle for LOADED_IMAGE_PROTOCOL\n");
- return NULL;
+ return status;
}

status = efi_low_alloc(sys_table, 0x4000, 1,
(unsigned long *)&boot_params);
if (status != EFI_SUCCESS) {
efi_printk(sys_table, "Failed to allocate lowmem for boot params\n");
- return NULL;
+ return status;
}

memset(boot_params, 0x0, 0x4000);
@@ -474,14 +455,17 @@ struct boot_params *make_boot_params(struct efi_config *c)
boot_params->ext_ramdisk_image = (u64)ramdisk_addr >> 32;
boot_params->ext_ramdisk_size = (u64)ramdisk_size >> 32;

- return boot_params;
+ hdr->code32_start = (u32)(unsigned long)startup_32;
+
+ efi_stub_entry(handle, sys_table, boot_params);
+ /* not reached */

fail2:
efi_free(sys_table, options_size, hdr->cmd_line_ptr);
fail:
efi_free(sys_table, 0x4000, (unsigned long)boot_params);

- return NULL;
+ return status;
}

static void add_e820ext(struct boot_params *params,
@@ -737,33 +721,26 @@ static efi_status_t exit_boot(struct boot_params *boot_params, void *handle)
* On success we return a pointer to a boot_params structure, and NULL
* on failure.
*/
-struct boot_params *
-efi_main(struct efi_config *c, struct boot_params *boot_params)
+struct boot_params *efi_main(efi_handle_t handle,
+ efi_system_table_t *sys_table_arg,
+ struct boot_params *boot_params,
+ bool is64)
{
struct desc_ptr *gdt = NULL;
struct setup_header *hdr = &boot_params->hdr;
efi_status_t status;
struct desc_struct *desc;
- void *handle;
- efi_system_table_t *_table;
unsigned long cmdline_paddr;

- efi_early = c;
-
- _table = (efi_system_table_t *)(unsigned long)efi_early->table;
- handle = (void *)(unsigned long)efi_early->image_handle;
+ sys_table = sys_table_arg;

- sys_table = _table;
+ if (IS_ENABLED(CONFIG_EFI_MIXED))
+ efi_is64 = is64;

/* Check if we were booted by the EFI firmware */
if (sys_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
goto fail;

- if (efi_is_64bit())
- setup_boot_services64(efi_early);
- else
- setup_boot_services32(efi_early);
-
/*
* make_boot_params() may have been called before efi_main(), in which
* case this is the second time we parse the cmdline. This is ok,
@@ -925,5 +902,6 @@ efi_main(struct efi_config *c, struct boot_params *boot_params)
fail:
efi_printk(sys_table, "efi_main() failed!\n");

- return NULL;
+ for (;;)
+ asm("hlt");
}
diff --git a/arch/x86/boot/compressed/head_32.S b/arch/x86/boot/compressed/head_32.S
index 0b03dc7bba12..e43ac17cb9fb 100644
--- a/arch/x86/boot/compressed/head_32.S
+++ b/arch/x86/boot/compressed/head_32.S
@@ -145,63 +145,16 @@ SYM_FUNC_START(startup_32)
SYM_FUNC_END(startup_32)

#ifdef CONFIG_EFI_STUB
-/*
- * We don't need the return address, so set up the stack so efi_main() can find
- * its arguments.
- */
-SYM_FUNC_START(efi_pe_entry)
- add $0x4, %esp
-
- call 1f
-1: popl %esi
- subl $1b, %esi
-
- popl %ecx
- movl %ecx, efi32_config(%esi) /* Handle */
- popl %ecx
- movl %ecx, efi32_config+8(%esi) /* EFI System table pointer */
-
- leal efi32_config(%esi), %eax
- pushl %eax
-
- call make_boot_params
- cmpl $0, %eax
- je fail
- movl %esi, BP_code32_start(%eax)
- popl %ecx
- pushl %eax
- pushl %ecx
- jmp 2f /* Skip efi_config initialization */
-SYM_FUNC_END(efi_pe_entry)
-
SYM_FUNC_START(efi32_stub_entry)
+SYM_FUNC_START_ALIAS(efi_stub_entry)
add $0x4, %esp
- popl %ecx
- popl %edx
-
- call 1f
-1: popl %esi
- subl $1b, %esi
-
- movl %ecx, efi32_config(%esi) /* Handle */
- movl %edx, efi32_config+8(%esi) /* EFI System table pointer */
-
- leal efi32_config(%esi), %eax
- pushl %eax
-2:
call efi_main
- cmpl $0, %eax
movl %eax, %esi
- jne 2f
-fail:
- /* EFI init failed, so hang. */
- hlt
- jmp fail
-2:
movl BP_code32_start(%esi), %eax
leal startup_32(%eax), %eax
jmp *%eax
SYM_FUNC_END(efi32_stub_entry)
+SYM_FUNC_END_ALIAS(efi_stub_entry)
#endif

.text
@@ -258,13 +211,6 @@ SYM_FUNC_START_LOCAL_NOALIGN(.Lrelocated)
jmp *%eax
SYM_FUNC_END(.Lrelocated)

-#ifdef CONFIG_EFI_STUB
- .data
-efi32_config:
- .fill 5,8,0
- .byte 0
-#endif
-
/*
* Stack and heap for uncompression
*/
diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S
index ad57edeaeeb3..a6f3ee9ca61d 100644
--- a/arch/x86/boot/compressed/head_64.S
+++ b/arch/x86/boot/compressed/head_64.S
@@ -208,10 +208,14 @@ SYM_FUNC_START(startup_32)
pushl $__KERNEL_CS
leal startup_64(%ebp), %eax
#ifdef CONFIG_EFI_MIXED
- movl efi32_config(%ebp), %ebx
+ movl efi32_boot_args(%ebp), %ebx
cmp $0, %ebx
jz 1f
leal handover_entry(%ebp), %eax
+ movl 0(%ebx), %edi
+ movl 4(%ebx), %esi
+ movl 8(%ebx), %edx
+ movl $0x0, %ecx
1:
#endif
pushl %eax
@@ -228,22 +232,14 @@ SYM_FUNC_END(startup_32)
.org 0x190
SYM_FUNC_START(efi32_stub_entry)
add $0x4, %esp /* Discard return address */
- popl %ecx
- popl %edx
- popl %esi

- leal (BP_scratch+4)(%esi), %esp
call 1f
1: pop %ebp
subl $1b, %ebp

- movl %ecx, efi32_config(%ebp)
- movl %edx, efi32_config+8(%ebp)
+ movl %esp, efi32_boot_args(%ebp)
sgdtl efi32_boot_gdt(%ebp)

- leal efi32_config(%ebp), %eax
- movl %eax, efi_config(%ebp)
-
/* Disable paging */
movl %cr0, %eax
btrl $X86_CR0_PG_BIT, %eax
@@ -450,51 +446,19 @@ trampoline_return:
SYM_CODE_END(startup_64)

#ifdef CONFIG_EFI_STUB
-
-/* The entry point for the PE/COFF executable is efi_pe_entry. */
-SYM_FUNC_START(efi_pe_entry)
- movq %rcx, efi64_config(%rip) /* Handle */
- movq %rdx, efi64_config+8(%rip) /* EFI System table pointer */
-
- leaq efi64_config(%rip), %rax
- movq %rax, efi_config(%rip)
-
- movq %rax, %rdi
- call make_boot_params
- cmpq $0,%rax
- je fail
- mov %rax, %rsi
- leaq startup_32(%rip), %rax
- movl %eax, BP_code32_start(%rsi)
-
-handover_entry:
- movq efi_config(%rip), %rdi
+ .org 0x390
+SYM_FUNC_START(efi64_stub_entry)
+SYM_FUNC_START_ALIAS(efi_stub_entry)
+ movq $1, %rcx
+SYM_INNER_LABEL(handover_entry, SYM_L_LOCAL)
and $~0xf, %rsp /* realign the stack */
call efi_main
movq %rax,%rsi
- cmpq $0,%rax
- jne 2f
-fail:
- /* EFI init failed, so hang. */
- hlt
- jmp fail
-2:
movl BP_code32_start(%esi), %eax
leaq startup_64(%rax), %rax
jmp *%rax
-SYM_FUNC_END(efi_pe_entry)
-
- .org 0x390
-SYM_FUNC_START(efi64_stub_entry)
- movq %rdi, efi64_config(%rip) /* Handle */
- movq %rsi, efi64_config+8(%rip) /* EFI System table pointer */
-
- leaq efi64_config(%rip), %rax
- movq %rax, efi_config(%rip)
-
- movq %rdx, %rsi
- jmp handover_entry
SYM_FUNC_END(efi64_stub_entry)
+SYM_FUNC_END_ALIAS(efi_stub_entry)
#endif

.text
@@ -663,22 +627,10 @@ SYM_DATA_START_LOCAL(gdt)
.quad 0x0000000000000000 /* TS continued */
SYM_DATA_END_LABEL(gdt, SYM_L_LOCAL, gdt_end)

-#ifdef CONFIG_EFI_STUB
-SYM_DATA_LOCAL(efi_config, .quad 0)
-
#ifdef CONFIG_EFI_MIXED
-SYM_DATA_START(efi32_config)
- .fill 5,8,0
- .byte 0
-SYM_DATA_END(efi32_config)
+SYM_DATA_LOCAL(efi32_boot_args, .long 0)
#endif

-SYM_DATA_START(efi64_config)
- .fill 5,8,0
- .byte 1
-SYM_DATA_END(efi64_config)
-#endif /* CONFIG_EFI_STUB */
-
/*
* Stack and heap for uncompression
*/
diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h
index 001905daa110..1817f350618e 100644
--- a/arch/x86/include/asm/efi.h
+++ b/arch/x86/include/asm/efi.h
@@ -200,32 +200,14 @@ static inline efi_status_t efi_thunk_set_virtual_address_map(

/* arch specific definitions used by the stub code */

-struct efi_config {
- u64 image_handle;
- u64 table;
- u64 runtime_services;
- u64 boot_services;
- u64 text_output;
- bool is64;
-} __packed;
-
-__pure const struct efi_config *__efi_early(void);
-
-static inline bool efi_is_64bit(void)
-{
- if (!IS_ENABLED(CONFIG_X86_64))
- return false;
-
- if (!IS_ENABLED(CONFIG_EFI_MIXED))
- return true;
-
- return __efi_early()->is64;
-}
+__pure bool efi_is_64bit(void);

static inline bool efi_is_native(void)
{
if (!IS_ENABLED(CONFIG_X86_64))
return true;
+ if (!IS_ENABLED(CONFIG_EFI_MIXED))
+ return true;
return efi_is_64bit();
}

@@ -252,18 +234,16 @@ static inline bool efi_is_native(void)

#define efi_call_early(f, ...) \
(efi_is_native() \
- ? ((efi_boot_services_t *)(unsigned long) \
- __efi_early()->boot_services)->f(__VA_ARGS__) \
- : efi64_thunk(((efi_boot_services_t *)(unsigned long) \
- __efi_early()->boot_services)->mixed_mode.f, \
+ ? efi_system_table()->boottime->f(__VA_ARGS__) \
+ : efi64_thunk(efi_table_attr(efi_boot_services, \
+ boottime, efi_system_table())->mixed_mode.f, \
__VA_ARGS__))

#define efi_call_runtime(f, ...) \
(efi_is_native() \
- ? ((efi_runtime_services_t *)(unsigned long) \
- __efi_early()->runtime_services)->f(__VA_ARGS__)\
- : efi64_thunk(((efi_runtime_services_t *)(unsigned long)\
- __efi_early()->runtime_services)->mixed_mode.f, \
+ ? efi_system_table()->runtime->f(__VA_ARGS__) \
+ : efi64_thunk(efi_table_attr(efi_runtime_services, \
+ runtime, efi_system_table())->mixed_mode.f, \
__VA_ARGS__))

extern bool efi_reboot_required(void);
--
2.20.1
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