There are a couple of places in the x86 EFI stub code where we select
between 32-bit and 64-bit versions of the support routines based on
the value of efi_early->is64. Referencing that field directly is a
bad idea, since it prevents the compiler from inferring that this
field can never be true on a 32-bit build, and can only become false
on a 64-bit build if support for mixed mode is compiled in. This
results in dead code to be retained in the uncompressed part of the
kernel image, which is wasteful.

So switch to the efi_is_64bit() helper, which will resolve to a
constant boolean unless building for 64-bit with mixed mode support.

Signed-off-by: Ard Biesheuvel <>
 arch/x86/boot/compressed/eboot.c | 15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
index 92b573fd239c..b492fba230ea 100644
--- a/arch/x86/boot/compressed/eboot.c
+++ b/arch/x86/boot/compressed/eboot.c
@@ -98,7 +98,7 @@ static inline efi_status_t __open_volume64(void *__image, 
void **__fh)
 efi_open_volume(efi_system_table_t *sys_table, void *__image, void **__fh)
-       if (efi_early->is64)
+       if (efi_is_64bit())
                return __open_volume64(__image, __fh);
        return __open_volume32(__image, __fh);
@@ -467,7 +467,7 @@ struct boot_params *make_boot_params(struct efi_config *c)
        if (sys_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
                return NULL;
-       if (efi_early->is64)
+       if (efi_is_64bit())
@@ -746,8 +746,7 @@ static efi_status_t exit_boot_func(efi_system_table_t 
        return EFI_SUCCESS;
-static efi_status_t exit_boot(struct boot_params *boot_params,
-                             void *handle, bool is64)
+static efi_status_t exit_boot(struct boot_params *boot_params, void *handle)
        unsigned long map_sz, key, desc_size, buff_size;
        efi_memory_desc_t *mem_map;
@@ -768,7 +767,7 @@ static efi_status_t exit_boot(struct boot_params 
        priv.efi                = &boot_params->efi_info;
        priv.e820ext            = NULL;
        priv.e820ext_size       = 0;
-       priv.is64               = is64;
+       priv.is64               = efi_is_64bit();
        /* Might as well exit boot services now */
        status = efi_exit_boot_services(sys_table, handle, &map, &priv,
@@ -803,13 +802,11 @@ efi_main(struct efi_config *c, struct boot_params 
        struct desc_struct *desc;
        void *handle;
        efi_system_table_t *_table;
-       bool is64;
        efi_early = c;
        _table = (efi_system_table_t *)(unsigned long)efi_early->table;
        handle = (void *)(unsigned long)efi_early->image_handle;
-       is64 = efi_early->is64;
        sys_table = _table;
@@ -817,7 +814,7 @@ efi_main(struct efi_config *c, struct boot_params 
        if (sys_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
                goto fail;
-       if (is64)
+       if (efi_is_64bit())
@@ -873,7 +870,7 @@ efi_main(struct efi_config *c, struct boot_params 
                hdr->code32_start = bzimage_addr;
-       status = exit_boot(boot_params, handle, is64);
+       status = exit_boot(boot_params, handle);
        if (status != EFI_SUCCESS) {
                efi_printk(sys_table, "exit_boot() failed!\n");
                goto fail;

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