8000 Add Arm Assembly (aarch64) support for RNG · openssl/openssl@45c74de · GitHub
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Add Arm Assembly (aarch64) support for RNG
Include aarch64 asm instructions for random number generation using the RNDR and RNDRRS instructions. Provide detection functions for RNDR and RNDRRS getauxval. Reviewed-by: Paul Dale <pauli@openssl.org> Reviewed-by: Tomas Mraz <tomas@openssl.org> (Merged from #15361) (cherry picked from commit efa1f22)
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‎crypto/arm64cpuid.pl

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@@ -161,7 +161,67 @@
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lsr w0,w0,#31
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ret
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.size CRYPTO_memcmp,.-CRYPTO_memcmp
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.globl _armv8_rng_probe
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.type _armv8_rng_probe,%function
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_armv8_rng_probe:
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mrs x0, s3_3_c2_c4_0 // rndr
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mrs x0, s3_3_c2_c4_1 // rndrrs
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ret
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.size _armv8_rng_probe,.-_armv8_rng_probe
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___
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sub gen_random {
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my $rdop = shift;
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my $rand_reg = $rdop eq "rndr" ? "s3_3_c2_c4_0" : "s3_3_c2_c4_1";
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print<<___;
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// Fill buffer with Randomly Generated Bytes
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// inputs: char * in x0 - Pointer to buffer
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// size_t in x1 - Number of bytes to write to buffer
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// outputs: size_t in x0 - Number of bytes successfully written to buffer
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.globl OPENSSL_${rdop}_asm
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.type OPENSSL_${rdop}_asm,%function
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.align 4
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OPENSSL_${rdop}_asm:
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mov x2,xzr
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mov x3,xzr
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.align 4
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.Loop_${rdop}:
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cmp x1,#0
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b.eq .${rdop}_done
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mov x3,xzr
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mrs x3,$rand_reg
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b.eq .${rdop}_done
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cmp x1,#8
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b.lt .Loop_single_byte_${rdop}
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str x3,[x0]
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add x0,x0,#8
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add x2,x2,#8
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subs x1,x1,#8
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b.ge .Loop_${rdop}
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.align 4
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.Loop_single_byte_${rdop}:
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strb w3,[x0]
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lsr x3,x3,#8
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add x2,x2,#1
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add x0,x0,#1
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subs x1,x1,#1
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b.gt .Loop_single_byte_${rdop}
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.align 4
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.${rdop}_done:
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mov x0,x2
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ret
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.size OPENSSL_${rdop}_asm,.-OPENSSL_${rdop}_asm
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___
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}
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gen_random("rndr");
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gen_random("rndrrs");
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print $code;
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close STDOUT or die "error closing STDOUT: $!";

‎crypto/arm_arch.h

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@@ -83,6 +83,7 @@ extern unsigned int OPENSSL_armv8_rsa_neonized;
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# define ARMV8_PMULL (1<<5)
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# define ARMV8_SHA512 (1<<6)
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# define ARMV8_CPUID (1<<7)
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# define ARMV8_RNG (1<<8)
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/*
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* MIDR_EL1 system register

‎crypto/armcap.c

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Original file line numberDiff line numberDiff line change
@@ -17,6 +17,7 @@
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#include <sys/sysctl.h>
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#endif
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#include "internal/cryptlib.h"
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#include <unistd.h>
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#include "arm_arch.h"
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@@ -54,6 +55,37 @@ void _armv8_pmull_probe(void);
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# ifdef __aarch64__
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void _armv8_sha512_probe(void);
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unsigned int _armv8_cpuid_probe(void);
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void _armv8_rng_probe(void);
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size_t OPENSSL_rndr_asm(unsigned char *buf, size_t len);
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size_t OPENSSL_rndrrs_asm(unsigned char *buf, size_t len);
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size_t OPENSSL_rndr_bytes(unsigned char *buf, size_t len);
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size_t OPENSSL_rndrrs_bytes(unsigned char *buf, size_t len);
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static size_t OPENSSL_rndr_wrapper(size_t (*func)(unsigned char *, size_t), unsigned char *buf, size_t len)
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{
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size_t buffer_size;
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int i;
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for (i = 0; i < 8; i++) {
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buffer_size = func(buf, len);
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if (buffer_size == len)
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break;
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usleep(5000); /* 5000 microseconds (5 milliseconds) */
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}
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return buffer_size;
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}
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size_t OPENSSL_rndr_bytes(unsigned char *buf, size_t len)
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{
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return OPENSSL_rndr_wrapper(OPENSSL_rndr_asm, buf, len);
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}
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size_t OPENSSL_rndrrs_bytes(unsigned char *buf, size_t len)
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{
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return OPENSSL_rndr_wrapper(OPENSSL_rndrrs_asm, buf, len);
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}
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# endif
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uint32_t _armv7_tick(void);
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@@ -138,6 +170,9 @@ static unsigned long getauxval(unsigned long key)
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# define HWCAP_CE_SHA256 (1 << 6)
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# define HWCAP_CPUID (1 << 11)
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# define HWCAP_CE_SHA512 (1 << 21)
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/* AT_HWCAP2 */
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# define HWCAP2 26
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# define HWCAP2_RNG (1 << 16)
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# endif
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void OPENSSL_cpuid_setup(void)
@@ -212,6 +247,10 @@ void OPENSSL_cpuid_setup(void)
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OPENSSL_armcap_P |= ARMV8_CPUID;
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# endif
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}
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# ifdef __aarch64__
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if (getauxval(HWCAP2) & HWCAP2_RNG)
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OPENSSL_armcap_P |= ARMV8_RNG;
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# endif
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# endif
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sigfillset(&all_masked);
@@ -255,6 +294,12 @@ void OPENSSL_cpuid_setup(void)
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}
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# endif
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}
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# ifdef __aarch64__
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if (sigsetjmp(ill_jmp, 1) == 0) {
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_armv8_rng_probe();
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OPENSSL_armcap_P |= ARMV8_RNG;
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}
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# endif
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# endif
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/*

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