From 8f65619ac629e0c681d450469680fe8bae5785b1 Mon Sep 17 00:00:00 2001
From: Simon Rettberg
Date: Tue, 4 Apr 2023 15:25:21 +0200
Subject: [efi] Remove old RDRAND hack; now officially supported

---
 src/interface/efi/efi_entropy.c | 47 -----------------------------------------
 1 file changed, 47 deletions(-)

(limited to 'src')

diff --git a/src/interface/efi/efi_entropy.c b/src/interface/efi/efi_entropy.c
index 8e55c77b1..cda1c3640 100644
--- a/src/interface/efi/efi_entropy.c
+++ b/src/interface/efi/efi_entropy.c
@@ -28,11 +28,6 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 #include <ipxe/profile.h>
 #include <ipxe/efi/efi.h>
 
-#if defined(__i386) || defined(__x86_64)
-#include <ipxe/cpuid.h>
-static char have_hwrnd = 0;
-#endif
-
 /** @file
  *
  * EFI entropy source
@@ -132,44 +127,6 @@ static int efi_entropy_tick ( void ) {
 	return low;
 }
 
-/**
- * Get noise sample from rdrand
- *
- * @ret noise		Noise sample
- * @ret rc		Return status code
- */
-static int efi_get_noise_rdrand ( noise_sample_t *noise ) {
-#if defined(__i386) || defined(__x86_64)
-	if ( have_hwrnd == 0 ) {
-		struct x86_features features;
-		x86_features( &features );
-		if ( features.intel.ecx & ( 1 << 30 ) ) {
-			have_hwrnd = 1;
-		} else {
-			have_hwrnd = 2;
-		}
-		DBGC( &tick, "Have RDRAND: %s\n", ( have_hwrnd == 1 ? "YES!" : "NO :-(" ) );
-	}
-	if ( have_hwrnd == 1 ) {
-		int ret, retries = 10;
-		char ok;
-		while ( --retries > 0 ) {
-			__asm__ volatile ( "rdrand %0; setc %1" : "=r" ( ret ), "=qm" ( ok ) );
-			if ( ok ) {
-				if ( ret == -1 ) {
-					/* Assume this is a broken AMD CPU, fall back to TSC */
-					ret = profile_timestamp();
-				}
-				*noise = ret;
-				return 0;
-			}
-		}
-		return -EBUSY;
-	}
-#endif
-	return -ENOTSUP;
-}
-
 /**
  * Get noise sample from timer ticks
  *
@@ -181,10 +138,6 @@ static int efi_get_noise ( noise_sample_t *noise ) {
 	int after;
 	int rc;
 
-	rc = efi_get_noise_rdrand ( noise );
-	if ( rc == 0 )
-		return 0;
-
 	/* Wait for a timer tick */
 	before = efi_entropy_tick();
 	if ( before < 0 ) {
-- 
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