[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 <dbraz...@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

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