efi/x86: Move x86 back to libstub
This reverts commit 84be880560fb, 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: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index 704f58a..20db5b3 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -35,7 +35,8 @@
$(obj)/eboot.o: KBUILD_CFLAGS += -fshort-wchar -mno-red-zone
-vmlinux-objs-$(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)
diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
index 1acf605..92b9a5f 100644
--- a/arch/x86/boot/compressed/eboot.c
+++ b/arch/x86/boot/compressed/eboot.c
@@ -21,8 +21,10 @@
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 @@
}
}
-#include "../../../../drivers/firmware/efi/libstub/efi-stub-helper.c"
-
static void find_bits(unsigned long mask, u8 *pos, u8 *size)
{
u8 first, len;
diff --git a/arch/x86/boot/compressed/eboot.h b/arch/x86/boot/compressed/eboot.h
index c88c31e..d487e72 100644
--- a/arch/x86/boot/compressed/eboot.h
+++ b/arch/x86/boot/compressed/eboot.h
@@ -103,20 +103,4 @@
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 */
diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h
index 9b11757..25bce45 100644
--- a/arch/x86/include/asm/efi.h
+++ b/arch/x86/include/asm/efi.h
@@ -158,6 +158,30 @@
}
#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
diff --git a/drivers/firmware/efi/Makefile b/drivers/firmware/efi/Makefile
index aef6a95..d8be608 100644
--- a/drivers/firmware/efi/Makefile
+++ b/drivers/firmware/efi/Makefile
@@ -7,4 +7,4 @@
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/