Commit f7a4825d authored by David Brazdil's avatar David Brazdil Committed by Marc Zyngier
Browse files

KVM: arm64: Add symbol at the beginning of each hyp section 



Generating hyp relocations will require referencing positions at a given
offset from the beginning of hyp sections. Since the final layout will
not be determined until the linking of `vmlinux`, modify the hyp linker
script to insert a symbol at the first byte of each hyp section to use
as an anchor. The linker of `vmlinux` will place the symbols together
with the sections.

Signed-off-by: default avatarDavid Brazdil <dbrazdil@google.com>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210105180541.65031-4-dbrazdil@google.com
parent 16174eea

arch/arm64/include/asm/hyp_image.h

+27 −2
Original line number Diff line number Diff line
@@ -7,6 +7,9 @@ 
#ifndef __ARM64_HYP_IMAGE_H__

#define __ARM64_HYP_IMAGE_H__



#define __HYP_CONCAT(a, b)	a ## b

#define HYP_CONCAT(a, b)	__HYP_CONCAT(a, b)



/*

 * KVM nVHE code has its own symbol namespace prefixed with __kvm_nvhe_,

 * to separate it from the kernel proper.
@@ -21,9 +24,31 @@ 
 */

#define HYP_SECTION_NAME(NAME)	.hyp##NAME



/* Symbol defined at the beginning of each hyp section. */

#define HYP_SECTION_SYMBOL_NAME(NAME) \

	HYP_CONCAT(__hyp_section_, HYP_SECTION_NAME(NAME))



/*

 * Helper to generate linker script statements starting a hyp section.

 *

 * A symbol with a well-known name is defined at the first byte. This

 * is used as a base for hyp relocations (see gen-hyprel.c). It must

 * be defined inside the section so the linker of `vmlinux` cannot

 * separate it from the section data.

 */

#define BEGIN_HYP_SECTION(NAME)				\

	HYP_SECTION_NAME(NAME) : {			\

		HYP_SECTION_SYMBOL_NAME(NAME) = .;



/* Helper to generate linker script statements ending a hyp section. */

#define END_HYP_SECTION					\

	}



/* Defines an ELF hyp section from input section @NAME and its subsections. */

#define HYP_SECTION(NAME)			\

	HYP_SECTION_NAME(NAME) : { *(NAME NAME##.*) }

	BEGIN_HYP_SECTION(NAME)			\

		*(NAME NAME##.*)		\

	END_HYP_SECTION



/*

 * Defines a linker script alias of a kernel-proper symbol referenced by

arch/arm64/kvm/hyp/nvhe/hyp.lds.S

+2 −2
Original line number Diff line number Diff line
@@ -22,7 +22,7 @@ SECTIONS { 
	 * alignment for when linking into vmlinux.

	 */

	. = ALIGN(PAGE_SIZE);

	HYP_SECTION_NAME(.data..percpu) : {

	BEGIN_HYP_SECTION(.data..percpu)

		PERCPU_INPUT(L1_CACHE_BYTES)

	}

	END_HYP_SECTION

}