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

Ard Biesheuvel · Ingo Molnar · commit 57fdb89aeb7b · 2016-04-28T11:33:59.000+02:00
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
@@ -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
@@ -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
@@ -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
 

Original file line number	Diff line number	Diff line change
`@@ -56,6 +56,9 @@ static __init pteval_t create_mapping_protection(efi_memory_desc_t *md)`
`56`	`56`	`return pgprot_val(PAGE_KERNEL_EXEC);`
`57`	`57`	`}`
`58`	`58`
	`59`	`+/* we will fill this structure from the stub, so don't put it in .bss */`
	`60`	`+struct screen_info screen_info __section(.data);`
	`61`	`+`
`59`	`62`	`int __init efi_create_mapping(struct mm_struct mm, efi_memory_desc_t md)`
`60`	`63`	`{`
`61`	`64`	`pteval_t prot_val = create_mapping_protection(md);`