Skip to content

Commit

Permalink
efi/libstub/x86: Drop __efi_early() export and efi_config struct
Browse files Browse the repository at this point in the history 
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>
Cc: Arvind Sankar <nivedita@alum.mit.edu>
Cc: Borislav Petkov <bp@alien8.de>
Cc: James Morse <james.morse@arm.com>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: https://lkml.kernel.org/r/20191224151025.32482-18-ardb@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
  • Loading branch information
Ard Biesheuvel authored and Ingo Molnar committed Dec 25, 2019
1 parent dc29da1 commit c3710de
Show file tree
Hide file tree
Showing 4 changed files with 54 additions and 198 deletions.
82 changes: 30 additions & 52 deletions arch/x86/boot/compressed/eboot.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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)
Expand Down Expand Up @@ -367,53 +352,49 @@ 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;
char *cmdline_ptr;
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);
Expand Down Expand Up @@ -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,
Expand Down Expand Up @@ -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,
Expand Down Expand Up @@ -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");
}
58 changes: 2 additions & 56 deletions arch/x86/boot/compressed/head_32.S
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand Down Expand Up @@ -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
*/
Expand Down
74 changes: 13 additions & 61 deletions arch/x86/boot/compressed/head_64.S
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand All @@ -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
Expand Down Expand Up @@ -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
Expand Down Expand Up @@ -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
*/
Expand Down
Loading

0 comments on commit c3710de

Please sign in to comment.