arm64/efi/libstub: Make screen_info accessible to the UEFI stub

Unlike on 32-bit ARM, where we need to pass the stub's version of struct
screen_info to the kernel proper via a configuration table, on 64-bit ARM
it simply involves making the core kernel's copy of struct screen_info
visible to the stub by exposing an __efistub_ alias for it.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: David Herrmann <dh.herrmann@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Jones <pjones@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1461614832-17633-21-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/arm64/include/asm/efi.h b/arch/arm64/include/asm/efi.h
index af40baa5d53f933c0764f5bdb833ebdc38923dc3..fa09886f72e6a38f66bac74ec6e82ba17f36c9f4 100644 (file)
--- a/arch/arm64/include/asm/efi.h
+++ b/arch/arm64/include/asm/efi.h
@@ -56,6 +56,9 @@ int efi_create_mapping(struct mm_struct *mm, efi_memory_desc_t *md);
 #define __efi_call_early(f, ...)       f(__VA_ARGS__)
 #define efi_is_64bit()                 (true)
 
+#define alloc_screen_info(x...)                &screen_info
+#define free_screen_info(x...)
+
 #define EFI_ALLOC_ALIGN                SZ_64K
 
 /*

diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c
index 33a6da160a501cee06657a31e1ab2d050f42c7b4..78f52488f9ff82461f2933689b44e7b0fcf74b80 100644 (file)
--- a/arch/arm64/kernel/efi.c
+++ b/arch/arm64/kernel/efi.c
@@ -56,6 +56,9 @@ static __init pteval_t create_mapping_protection(efi_memory_desc_t *md)
        return pgprot_val(PAGE_KERNEL_EXEC);
 }
 
+/* we will fill this structure from the stub, so don't put it in .bss */
+struct screen_info screen_info __section(.data);
+
 int __init efi_create_mapping(struct mm_struct *mm, efi_memory_desc_t *md)
 {
        pteval_t prot_val = create_mapping_protection(md);

diff --git a/arch/arm64/kernel/image.h b/arch/arm64/kernel/image.h
index 5e360ce88f10ba4110697552a47ea8c42053a02f..1428849aece8f98a52b4661c68c14ea555fe0000 100644 (file)
--- a/arch/arm64/kernel/image.h
+++ b/arch/arm64/kernel/image.h
@@ -112,6 +112,7 @@ __efistub___memset          = KALLSYMS_HIDE(__pi_memset);
 __efistub__text                        = KALLSYMS_HIDE(_text);
 __efistub__end                 = KALLSYMS_HIDE(_end);
 __efistub__edata               = KALLSYMS_HIDE(_edata);
+__efistub_screen_info          = KALLSYMS_HIDE(screen_info);
 
 #endif