Commit 243b6754 authored by Ard Biesheuvel's avatar Ard Biesheuvel Committed by Matt Fleming
Browse files

efi/x86: Move x86 back to libstub

This reverts commit 84be8805

, which itself reverted my original
attempt to move x86 from #include'ing .c files from across the tree
to using the EFI stub built as a static library.

The issue that affected the original approach was that splitting
the implementation into several .o files resulted in the variable
'efi_early' becoming a global with external linkage, which under
-fPIC implies that references to it must go through the GOT. However,
dealing with this additional GOT entry turned out to be troublesome
on some EFI implementations. (GCC's visibility=hidden attribute is
supposed to lift this requirement, but it turned out not to work on
the 32-bit build.)

Instead, use a pure getter function to get a reference to efi_early.
This approach results in no additional GOT entries being generated,
so there is no need for any changes in the early GOT handling.
Tested-by: default avatarMaarten Lankhorst <maarten.lankhorst@canonical.com>
Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: default avatarMatt Fleming <matt.fleming@intel.com>
parent af5a29ae
......@@ -35,7 +35,8 @@ vmlinux-objs-$(CONFIG_RANDOMIZE_BASE) += $(obj)/aslr.o
$(obj)/eboot.o: KBUILD_CFLAGS += -fshort-wchar -mno-red-zone
vmlinux-objs-$(CONFIG_EFI_STUB) += $(obj)/eboot.o $(obj)/efi_stub_$(BITS).o
vmlinux-objs-$(CONFIG_EFI_STUB) += $(obj)/eboot.o $(obj)/efi_stub_$(BITS).o \
$(objtree)/drivers/firmware/efi/libstub/lib.a
$(obj)/vmlinux: $(vmlinux-objs-y) FORCE
$(call if_changed,ld)
......
......@@ -21,8 +21,10 @@ static efi_system_table_t *sys_table;
static struct efi_config *efi_early;
#define efi_call_early(f, ...) \
efi_early->call(efi_early->f, __VA_ARGS__);
__pure const struct efi_config *__efi_early(void)
{
return efi_early;
}
#define BOOT_SERVICES(bits) \
static void setup_boot_services##bits(struct efi_config *c) \
......@@ -285,8 +287,6 @@ void efi_char16_printk(efi_system_table_t *table, efi_char16_t *str)
}
}
#include "../../../../drivers/firmware/efi/libstub/efi-stub-helper.c"
static void find_bits(unsigned long mask, u8 *pos, u8 *size)
{
u8 first, len;
......
......@@ -103,20 +103,4 @@ struct efi_uga_draw_protocol {
void *blt;
};
struct efi_config {
u64 image_handle;
u64 table;
u64 allocate_pool;
u64 allocate_pages;
u64 get_memory_map;
u64 free_pool;
u64 free_pages;
u64 locate_handle;
u64 handle_protocol;
u64 exit_boot_services;
u64 text_output;
efi_status_t (*call)(unsigned long, ...);
bool is64;
} __packed;
#endif /* BOOT_COMPRESSED_EBOOT_H */
......@@ -158,6 +158,30 @@ static inline efi_status_t efi_thunk_set_virtual_address_map(
}
#endif /* CONFIG_EFI_MIXED */
/* arch specific definitions used by the stub code */
struct efi_config {
u64 image_handle;
u64 table;
u64 allocate_pool;
u64 allocate_pages;
u64 get_memory_map;
u64 free_pool;
u64 free_pages;
u64 locate_handle;
u64 handle_protocol;
u64 exit_boot_services;
u64 text_output;
efi_status_t (*call)(unsigned long, ...);
bool is64;
} __packed;
__pure const struct efi_config *__efi_early(void);
#define efi_call_early(f, ...) \
__efi_early()->call(__efi_early()->f, __VA_ARGS__);
extern bool efi_reboot_required(void);
#else
......
......@@ -7,4 +7,4 @@ obj-$(CONFIG_EFI_VARS_PSTORE) += efi-pstore.o
obj-$(CONFIG_UEFI_CPER) += cper.o
obj-$(CONFIG_EFI_RUNTIME_MAP) += runtime-map.o
obj-$(CONFIG_EFI_RUNTIME_WRAPPERS) += runtime-wrappers.o
obj-$(CONFIG_EFI_ARM_STUB) += libstub/
obj-$(CONFIG_EFI_STUB) += libstub/
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