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    Subject[PATCH v2 01/10] Macros to override naming of percpu symbols and sections
    Date
    Modify generic linker script macros to generate section/symbol names for
    percpu area using overridable macros. No functional changes.

    This will allow arm64 linker script to define a second KVM-specific percpu
    data section using the generic PERCPU_SECTION macro.

    Signed-off-by: David Brazdil <dbrazdil@google.com>
    ---
    include/asm-generic/vmlinux.lds.h | 40 +++++++++++++++++++++----------
    1 file changed, 27 insertions(+), 13 deletions(-)

    diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
    index 5430febd34be..8f3f5c45e891 100644
    --- a/include/asm-generic/vmlinux.lds.h
    +++ b/include/asm-generic/vmlinux.lds.h
    @@ -920,6 +920,20 @@
    #define INIT_RAM_FS
    #endif

    +/*
    + * Macros to override the naming of percpu symbols and sections.
    + * Used by arm64 linker script to define a separate percpu area for KVM.
    + */
    +#define PERCPU_SECTION_BASE_NAME .data..percpu
    +
    +#ifndef PERCPU_SECTION_NAME
    +#define PERCPU_SECTION_NAME(suffix) PERCPU_SECTION_BASE_NAME ## suffix
    +#endif
    +
    +#ifndef PERCPU_SYMBOL_NAME
    +#define PERCPU_SYMBOL_NAME(name) name
    +#endif
    +
    /*
    * Memory encryption operates on a page basis. Since we need to clear
    * the memory encryption mask for this section, it needs to be aligned
    @@ -931,7 +945,7 @@
    #ifdef CONFIG_AMD_MEM_ENCRYPT
    #define PERCPU_DECRYPTED_SECTION \
    . = ALIGN(PAGE_SIZE); \
    - *(.data..percpu..decrypted) \
    + *(PERCPU_SECTION_NAME(..decrypted)) \
    . = ALIGN(PAGE_SIZE);
    #else
    #define PERCPU_DECRYPTED_SECTION
    @@ -975,17 +989,17 @@
    * sharing between subsections for different purposes.
    */
    #define PERCPU_INPUT(cacheline) \
    - __per_cpu_start = .; \
    - *(.data..percpu..first) \
    + PERCPU_SYMBOL_NAME(__per_cpu_start) = .; \
    + *(PERCPU_SECTION_NAME(..first)) \
    . = ALIGN(PAGE_SIZE); \
    - *(.data..percpu..page_aligned) \
    + *(PERCPU_SECTION_NAME(..page_aligned)) \
    . = ALIGN(cacheline); \
    - *(.data..percpu..read_mostly) \
    + *(PERCPU_SECTION_NAME(..read_mostly)) \
    . = ALIGN(cacheline); \
    - *(.data..percpu) \
    - *(.data..percpu..shared_aligned) \
    + *(PERCPU_SECTION_NAME()) \
    + *(PERCPU_SECTION_NAME(..shared_aligned)) \
    PERCPU_DECRYPTED_SECTION \
    - __per_cpu_end = .;
    + PERCPU_SYMBOL_NAME(__per_cpu_end) = .;

    /**
    * PERCPU_VADDR - define output section for percpu area
    @@ -1012,11 +1026,11 @@
    * address, use PERCPU_SECTION.
    */
    #define PERCPU_VADDR(cacheline, vaddr, phdr) \
    - __per_cpu_load = .; \
    - .data..percpu vaddr : AT(__per_cpu_load - LOAD_OFFSET) { \
    + PERCPU_SYMBOL_NAME(__per_cpu_load) = .; \
    + PERCPU_SECTION_NAME() vaddr : AT(PERCPU_SYMBOL_NAME(__per_cpu_load) - LOAD_OFFSET) { \
    PERCPU_INPUT(cacheline) \
    } phdr \
    - . = __per_cpu_load + SIZEOF(.data..percpu);
    + . = PERCPU_SYMBOL_NAME(__per_cpu_load) + SIZEOF(PERCPU_SECTION_NAME());

    /**
    * PERCPU_SECTION - define output section for percpu area, simple version
    @@ -1032,8 +1046,8 @@
    */
    #define PERCPU_SECTION(cacheline) \
    . = ALIGN(PAGE_SIZE); \
    - .data..percpu : AT(ADDR(.data..percpu) - LOAD_OFFSET) { \
    - __per_cpu_load = .; \
    + PERCPU_SECTION_NAME() : AT(ADDR(PERCPU_SECTION_NAME()) - LOAD_OFFSET) { \
    + PERCPU_SYMBOL_NAME(__per_cpu_load) = .; \
    PERCPU_INPUT(cacheline) \
    }

    --
    2.28.0.402.g5ffc5be6b7-goog
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