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diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 4ace5af0e9a7..0d2a67e792ed 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1732,6 +1732,11 @@
 			Note that using this option lowers the security
 			provided by tboot because it makes the system
 			vulnerable to DMA attacks.
+		nobounce [Default off]
+			Disable bounce buffer for unstrusted devices such as
+			the Thunderbolt devices. This will treat the untrusted
+			devices as the trusted ones, hence might expose security
+			risks of DMA attacks.
 
 	intel_idle.max_cstate=	[KNL,HW,ACPI,X86]
 			0	disables intel_idle and fall back on acpi_idle.
@@ -1811,7 +1816,7 @@
 			  synchronously.
 
 	iommu.passthrough=
-			[ARM64] Configure DMA to bypass the IOMMU by default.
+			[ARM64, X86] Configure DMA to bypass the IOMMU by default.
 			Format: { "0" | "1" }
 			0 - Use IOMMU translation for DMA.
 			1 - Bypass the IOMMU for DMA.
@@ -2604,7 +2609,7 @@
 				expose users to several CPU vulnerabilities.
 				Equivalent to: nopti [X86,PPC]
 					       kpti=0 [ARM64]
-					       nospectre_v1 [PPC]
+					       nospectre_v1 [X86,PPC]
 					       nobp=0 [S390]
 					       nospectre_v2 [X86,PPC,S390,ARM64]
 					       spectre_v2_user=off [X86]
@@ -2965,9 +2970,9 @@
 			nosmt=force: Force disable SMT, cannot be undone
 				     via the sysfs control file.
 
-	nospectre_v1	[PPC] Disable mitigations for Spectre Variant 1 (bounds
-			check bypass). With this option data leaks are possible
-			in the system.
+	nospectre_v1	[X86,PPC] Disable mitigations for Spectre Variant 1
+			(bounds check bypass). With this option data leaks are
+			possible in the system.
 
 	nospectre_v2	[X86,PPC_FSL_BOOK3E,ARM64] Disable all mitigations for
 			the Spectre variant 2 (indirect branch prediction)
@@ -4090,6 +4095,13 @@
 			Run specified binary instead of /init from the ramdisk,
 			used for early userspace startup. See initrd.
 
+	rdrand=		[X86]
+			force - Override the decision by the kernel to hide the
+				advertisement of RDRAND support (this affects
+				certain AMD processors because of buggy BIOS
+				support, specifically around the suspend/resume
+				path).
+
 	rdt=		[HW,X86,RDT]
 			Turn on/off individual RDT features. List is:
 			cmt, mbmtotal, mbmlocal, l3cat, l3cdp, l2cat, l2cdp,