On Dec 2, 2021, at 06:21, Peter Zijlstra [off-list ref] wrote:

On Wed, Nov 24, 2021 at 12:06:56PM -0800, Chang S. Bae wrote:

quoted

+	encodekey256 %eax, %eax

So this thing uses the fancy new keylocker instructions, however:

quoted

diff --git a/crypto/Kconfig b/crypto/Kconfig
index 285f82647d2b..784a04433549 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig

@@ -1113,6 +1113,50 @@ config CRYPTO_AES_NI_INTEL

	  ECB, CBC, LRW, XTS. The 64 bit version has additional
	  acceleration for CTR.

+config CRYPTO_AES_KL
+	tristate "AES cipher algorithms (AES-KL)"
+	depends on (LD_VERSION >= 23600) || (LLD_VERSION >= 120000)
+	depends on DM_CRYPT
+	select X86_KEYLOCKER
+	select CRYPTO_AES_NI_INTEL

There is no dependency on the compiler actually supporting them..

config AS_HAS_KEYLOCKER
	def_bool $(as-instr,encodekey256)

	depends on AS_HAS_KEYLOCKER

Hmm?

Well, LD_VERSION reflects the binutils version.

But yes, the as-instr macro looks to be useful here:

+config AS_HAS_KEYLOCKER
+       def_bool $(as-instr,encodekey256 %eax$(comma)%eax)
+       help
+         Supported by binutils >=2.36 and LLVM integrated assembler >= V12
+
 config CRYPTO_AES_KL
        tristate "AES cipher algorithms (AES-KL)"
-       depends on (LD_VERSION >= 23600) || (LLD_VERSION >= 120000)
+       depends on AS_HAS_KEYLOCKER

Thanks,
Chang