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    Subject[PATCH v3 15/17] x86/compressed: adhere to calling convention in get_sev_encryption_bit()
    Date
    Make get_sev_encryption_bit() follow the ordinary i386 calling
    convention, and only call it if CONFIG_AMD_MEM_ENCRYPT is actually
    enabled. This clarifies the calling code, and makes it more
    maintainable.

    Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
    ---
    arch/x86/boot/compressed/head_64.S | 5 +++--
    arch/x86/boot/compressed/mem_encrypt.S | 10 ----------
    2 files changed, 3 insertions(+), 12 deletions(-)

    diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S
    index 0cfc8ce273a2731c..dd18216cff5c37e0 100644
    --- a/arch/x86/boot/compressed/head_64.S
    +++ b/arch/x86/boot/compressed/head_64.S
    @@ -188,12 +188,13 @@ SYM_FUNC_START(startup_32)
    */
    /*
    * If SEV is active then set the encryption mask in the page tables.
    - * This will insure that when the kernel is copied and decompressed
    + * This will ensure that when the kernel is copied and decompressed
    * it will be done so encrypted.
    */
    - call get_sev_encryption_bit
    xorl %edx, %edx
    #ifdef CONFIG_AMD_MEM_ENCRYPT
    + call get_sev_encryption_bit
    + xorl %edx, %edx
    testl %eax, %eax
    jz 1f
    subl $32, %eax /* Encryption bit is always above bit 31 */
    diff --git a/arch/x86/boot/compressed/mem_encrypt.S b/arch/x86/boot/compressed/mem_encrypt.S
    index 14cf04a1ed091655..e69674588a31c81f 100644
    --- a/arch/x86/boot/compressed/mem_encrypt.S
    +++ b/arch/x86/boot/compressed/mem_encrypt.S
    @@ -18,12 +18,7 @@
    .text
    .code32
    SYM_FUNC_START(get_sev_encryption_bit)
    - xor %eax, %eax
    -
    -#ifdef CONFIG_AMD_MEM_ENCRYPT
    push %ebx
    - push %ecx
    - push %edx

    movl $0x80000000, %eax /* CPUID to check the highest leaf */
    cpuid
    @@ -54,12 +49,7 @@ SYM_FUNC_START(get_sev_encryption_bit)
    xor %eax, %eax

    .Lsev_exit:
    - pop %edx
    - pop %ecx
    pop %ebx
    -
    -#endif /* CONFIG_AMD_MEM_ENCRYPT */
    -
    RET
    SYM_FUNC_END(get_sev_encryption_bit)

    --
    2.35.1
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