[RFC PATCH 06/26] kvm: arm64: Add .hyp.data ELF section

[David Brazdil]

Add rules for renaming a .data ELF section in KVM nVHE object files to
.hyp.data, linking it into the kernel and mapping it in hyp at runtime.

Signed-off-by: David Brazdil <dbrazdil at google.com>
---
 arch/arm64/include/asm/sections.h |  1 +
 arch/arm64/kernel/vmlinux.lds.S   | 10 ++++++++++
 arch/arm64/kvm/arm.c              |  7 +++++++
 arch/arm64/kvm/hyp/nvhe/hyp.lds.S |  3 +++
 4 files changed, 21 insertions(+)

diff --git a/arch/arm64/include/asm/sections.h b/arch/arm64/include/asm/sections.h
index 3994169985ef..255f76f592d7 100644
--- a/arch/arm64/include/asm/sections.h
+++ b/arch/arm64/include/asm/sections.h
@@ -11,6 +11,7 @@ extern char __alt_instructions[], __alt_instructions_end[];
 extern char __hibernate_exit_text_start[], __hibernate_exit_text_end[];
 extern char __hyp_idmap_text_start[], __hyp_idmap_text_end[];
 extern char __hyp_text_start[], __hyp_text_end[];
+extern char __hyp_data_start[], __hyp_data_end[];
 extern char __idmap_text_start[], __idmap_text_end[];
 extern char __initdata_begin[], __initdata_end[];
 extern char __inittext_begin[], __inittext_end[];
diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S
index 1bda604f4c70..a9a1612c084f 100644
--- a/arch/arm64/kernel/vmlinux.lds.S
+++ b/arch/arm64/kernel/vmlinux.lds.S
@@ -30,6 +30,13 @@ jiffies = jiffies_64;
 	*(__kvm_ex_table)					\
 	__stop___kvm_ex_table = .;
 
+#define HYPERVISOR_DATA_SECTION					\
+	HYP_SECTION_NAME(.data) : {				\
+		__hyp_data_start = .;				\
+		*(HYP_SECTION_NAME(.data))			\
+		__hyp_data_end = .;				\
+	}
+
 #define HYPERVISOR_PERCPU_SECTION				\
 	. = ALIGN(PAGE_SIZE);					\
 	HYP_SECTION_NAME(.data..percpu) : {			\
@@ -37,6 +44,7 @@ jiffies = jiffies_64;
 	}
 #else /* CONFIG_KVM */
 #define HYPERVISOR_EXTABLE
+#define HYPERVISOR_DATA_SECTION
 #define HYPERVISOR_PERCPU_SECTION
 #endif
 
@@ -207,6 +215,8 @@ SECTIONS
 		EXIT_DATA
 	}
 
+	HYPERVISOR_DATA_SECTION
+
 	PERCPU_SECTION(L1_CACHE_BYTES)
 	HYPERVISOR_PERCPU_SECTION
 
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 5750ec34960e..8bb9fffe2a8f 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -1602,6 +1602,13 @@ static int init_hyp_mode(void)
 		goto out_err;
 	}
 
+	err = create_hyp_mappings(kvm_ksym_ref(__hyp_data_start),
+				  kvm_ksym_ref(__hyp_data_end), PAGE_HYP);
+	if (err) {
+		kvm_err("Cannot map hyp data section\n");
+		goto out_err;
+	}
+
 	err = create_hyp_mappings(kvm_ksym_ref(__start_rodata),
 				  kvm_ksym_ref(__end_rodata), PAGE_HYP_RO);
 	if (err) {
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp.lds.S b/arch/arm64/kvm/hyp/nvhe/hyp.lds.S
index bb2d986ff696..bc1664d365a9 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp.lds.S
+++ b/arch/arm64/kvm/hyp/nvhe/hyp.lds.S
@@ -16,4 +16,7 @@ SECTIONS {
 	HYP_SECTION_NAME(.data..percpu) : {
 		PERCPU_INPUT(L1_CACHE_BYTES)
 	}
+
+	/* Put after '.data..percpu' because its name matches the same regex. */
+	HYP_SECTION(.data)
 }
-- 
2.29.1.341.ge80a0c044ae-goog