From: Sean Christopherson <sean.j.christopherson@xxxxxxxxx> Allow building a minimal subset of the low-level AESNI functions by defining AESNI_INTEL_MINIMAL. The SGX Launch Enclave will utilize a small number of AESNI functions for creating CMACs when generating tokens for userspace enclaves. Reducing the size of the LE is high priority as EPC space is at a premium and initializing/measuring EPC pages is extremely slow, and defining only the minimal set of AESNI functions reduces the size of the in-kernel LE by over 50%. Because the LE is a (very) non-standard build environment, using linker tricks e.g. --gc-sections to remove the unused functions is not an option. Eliminating the unused AESNI functions also eliminates all usage of the retpoline macros, e.g. CALL_NOSPEC, which allows the LE linker script to assert that the alternatives and retpoline sections don't exist in the final binary. Because the LE's code cannot be patched, i.e. retpoline can't be enabled via alternatives, we want to assert that we're not expecting a security feature that can't be enabled. Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx> --- arch/x86/crypto/aesni-intel_asm.S | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/arch/x86/crypto/aesni-intel_asm.S b/arch/x86/crypto/aesni-intel_asm.S index e762ef417562..5a0a487466d5 100644 --- a/arch/x86/crypto/aesni-intel_asm.S +++ b/arch/x86/crypto/aesni-intel_asm.S @@ -45,6 +45,8 @@ #define MOVADQ movaps #define MOVUDQ movups +#ifndef AESNI_INTEL_MINIMAL + #ifdef __x86_64__ # constants in mergeable sections, linker can reorder and merge @@ -133,6 +135,8 @@ ALL_F: .octa 0xffffffffffffffffffffffffffffffff #define keysize 2*15*16(%arg1) #endif +#endif /* AESNI_INTEL_MINIMAL */ + #define STATE1 %xmm0 #define STATE2 %xmm4 @@ -506,6 +510,8 @@ _T_16_\@: _return_T_done_\@: .endm +#ifndef AESNI_INTEL_MINIMAL + #ifdef __x86_64__ /* GHASH_MUL MACRO to implement: Data*HashKey mod (128,127,126,121,0) * @@ -1760,6 +1766,7 @@ ENDPROC(aesni_gcm_finalize) #endif +#endif /* AESNI_INTEL_MINIMAL */ .align 4 _key_expansion_128: @@ -2031,6 +2038,8 @@ _aesni_enc1: ret ENDPROC(_aesni_enc1) +#ifndef AESNI_INTEL_MINIMAL + /* * _aesni_enc4: internal ABI * input: @@ -2840,3 +2849,5 @@ ENTRY(aesni_xts_crypt8) ENDPROC(aesni_xts_crypt8) #endif + +#endif /* AESNI_INTEL_MINIMAL */ -- 2.17.0
