1 files changed, 29 insertions, 1 deletions

diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index d0bb52296fa3..e03530aebfd0 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -242,6 +242,12 @@ SECTIONS
 		__x86_cpu_dev_end = .;
 	}
 
+	/*
+	 * start address and size of operations which during runtime
+	 * can be patched with virtualization friendly instructions or
+	 * baremetal native ones. Think page table operations.
+	 * Details in paravirt_types.h
+	 */
 	. = ALIGN(8);
 	.parainstructions : AT(ADDR(.parainstructions) - LOAD_OFFSET) {
 		__parainstructions = .;
@@ -249,6 +255,11 @@ SECTIONS
 		__parainstructions_end = .;
 	}
 
+	/*
+	 * struct alt_inst entries. From the header (alternative.h):
+	 * "Alternative instructions for different CPU types or capabilities"
+	 * Think locking instructions on spinlocks.
+	 */
 	. = ALIGN(8);
 	.altinstructions : AT(ADDR(.altinstructions) - LOAD_OFFSET) {
 		__alt_instructions = .;
@@ -256,11 +267,28 @@ SECTIONS
 		__alt_instructions_end = .;
 	}
 
+	/*
+	 * And here are the replacement instructions. The linker sticks
+	 * them as binary blobs. The .altinstructions has enough data to
+	 * get the address and the length of them to patch the kernel safely.
+	 */
 	.altinstr_replacement : AT(ADDR(.altinstr_replacement) - LOAD_OFFSET) {
 		*(.altinstr_replacement)
 	}
 
 	/*
+	 * struct iommu_table_entry entries are injected in this section.
+	 * It is an array of IOMMUs which during run time gets sorted depending
+	 * on its dependency order. After rootfs_initcall is complete
+	 * this section can be safely removed.
+	 */
+	.iommu_table : AT(ADDR(.iommu_table) - LOAD_OFFSET) {
+		__iommu_table = .;
+		*(.iommu_table)
+		__iommu_table_end = .;
+	}
+	. = ALIGN(8);
+	/*
 	 * .exit.text is discard at runtime, not link time, to deal with
 	 *  references from .altinstructions and .eh_frame
 	 */
@@ -273,7 +301,7 @@ SECTIONS
 	}
 
 #if !defined(CONFIG_X86_64) || !defined(CONFIG_SMP)
-	PERCPU(PAGE_SIZE)
+	PERCPU(THREAD_SIZE)
 #endif
 
 	. = ALIGN(PAGE_SIZE);