[PATCH] ARM: xip: Move XIP linking to a separate file

* [PATCH] ARM: xip: Move XIP linking to a separate file
@ 2015-11-19 14:24 ` Chris Brandt
  0 siblings, 0 replies; 14+ messages in thread
From: Chris Brandt @ 2015-11-19 14:24 UTC (permalink / raw)
  To: linux, mmarek
  Cc: linux-arm-kernel, linux-kbuild, nico, mcoquelin.stm32, kernel,
	Chris Brandt

When building an XIP kernel, the linker script needs to be much different
than a conventional kernel's script. Over time, it's been difficult to
maintain both XIP and non-XIP layouts in one linker script. Therefore,
this patch separates the two procedures into two completely different
files.

The new linker script is essentially a straight copy of the current script
with all the non-CONFIG_XIP_KERNEL portions removed.

Additionally, all CONFIG_XIP_KERNEL portions have been removed from the
existing linker script...never to return again.

From now on, for any architecture, when CONFIG_XIP_KERNEL is enabled, you
must provide a vmlinux-xip.lds.S for the build process.

Signed-off-by: Chris Brandt <chris.brandt@renesas.com>
---
 Makefile                          |    4 +
 arch/arm/kernel/.gitignore        |    1 +
 arch/arm/kernel/vmlinux-xip.lds.S |  322 +++++++++++++++++++++++++++++++++++++
 arch/arm/kernel/vmlinux.lds.S     |   31 +---
 4 files changed, 331 insertions(+), 27 deletions(-)
 create mode 100644 arch/arm/kernel/vmlinux-xip.lds.S

diff --git a/Makefile b/Makefile
index 3a0234f..b55440f 100644
--- a/Makefile
+++ b/Makefile
@@ -900,7 +900,11 @@ virt-y		:= $(patsubst %/, %/built-in.o, $(virt-y))
 # Externally visible symbols (used by link-vmlinux.sh)
 export KBUILD_VMLINUX_INIT := $(head-y) $(init-y)
 export KBUILD_VMLINUX_MAIN := $(core-y) $(libs-y) $(drivers-y) $(net-y) $(virt-y)
+ifdef CONFIG_XIP_KERNEL
+export KBUILD_LDS          := arch/$(SRCARCH)/kernel/vmlinux-xip.lds
+else
 export KBUILD_LDS          := arch/$(SRCARCH)/kernel/vmlinux.lds
+endif
 export LDFLAGS_vmlinux
 # used by scripts/pacmage/Makefile
 export KBUILD_ALLDIRS := $(sort $(filter-out arch/%,$(vmlinux-alldirs)) arch Documentation include samples scripts tools)
diff --git a/arch/arm/kernel/.gitignore b/arch/arm/kernel/.gitignore
index c5f676c..522c636 100644
--- a/arch/arm/kernel/.gitignore
+++ b/arch/arm/kernel/.gitignore
@@ -1 +1,2 @@
 vmlinux.lds
+vmlinux-xip.lds
diff --git a/arch/arm/kernel/vmlinux-xip.lds.S b/arch/arm/kernel/vmlinux-xip.lds.S
new file mode 100644
index 0000000..1fd938d
--- /dev/null
+++ b/arch/arm/kernel/vmlinux-xip.lds.S
@@ -0,0 +1,322 @@
+/* ld script to make ARM Linux kernel
+ * taken from the i386 version by Russell King
+ * Written by Martin Mares <mj@atrey.karlin.mff.cuni.cz>
+ */
+
+#include <asm-generic/vmlinux.lds.h>
+#include <asm/cache.h>
+#include <asm/thread_info.h>
+#include <asm/memory.h>
+#include <asm/page.h>
+#ifdef CONFIG_ARM_KERNMEM_PERMS
+#include <asm/pgtable.h>
+#endif
+
+#define PROC_INFO							\
+	. = ALIGN(4);							\
+	VMLINUX_SYMBOL(__proc_info_begin) = .;				\
+	*(.proc.info.init)						\
+	VMLINUX_SYMBOL(__proc_info_end) = .;
+
+#define IDMAP_TEXT							\
+	ALIGN_FUNCTION();						\
+	VMLINUX_SYMBOL(__idmap_text_start) = .;				\
+	*(.idmap.text)							\
+	VMLINUX_SYMBOL(__idmap_text_end) = .;				\
+	. = ALIGN(PAGE_SIZE);						\
+	VMLINUX_SYMBOL(__hyp_idmap_text_start) = .;			\
+	*(.hyp.idmap.text)						\
+	VMLINUX_SYMBOL(__hyp_idmap_text_end) = .;
+
+#ifdef CONFIG_HOTPLUG_CPU
+#define ARM_CPU_DISCARD(x)
+#define ARM_CPU_KEEP(x)		x
+#else
+#define ARM_CPU_DISCARD(x)	x
+#define ARM_CPU_KEEP(x)
+#endif
+
+#if (defined(CONFIG_SMP_ON_UP) && !defined(CONFIG_DEBUG_SPINLOCK)) || \
+	defined(CONFIG_GENERIC_BUG)
+#define ARM_EXIT_KEEP(x)	x
+#define ARM_EXIT_DISCARD(x)
+#else
+#define ARM_EXIT_KEEP(x)
+#define ARM_EXIT_DISCARD(x)	x
+#endif
+
+OUTPUT_ARCH(arm)
+ENTRY(stext)
+
+#ifndef __ARMEB__
+jiffies = jiffies_64;
+#else
+jiffies = jiffies_64 + 4;
+#endif
+
+SECTIONS
+{
+	/*
+	 * XXX: The linker does not define how output sections are
+	 * assigned to input sections when there are multiple statements
+	 * matching the same input section name.  There is no documented
+	 * order of matching.
+	 *
+	 * unwind exit sections must be discarded before the rest of the
+	 * unwind sections get included.
+	 */
+	/DISCARD/ : {
+		*(.ARM.exidx.exit.text)
+		*(.ARM.extab.exit.text)
+		ARM_CPU_DISCARD(*(.ARM.exidx.cpuexit.text))
+		ARM_CPU_DISCARD(*(.ARM.extab.cpuexit.text))
+		ARM_EXIT_DISCARD(EXIT_TEXT)
+		ARM_EXIT_DISCARD(EXIT_DATA)
+		EXIT_CALL
+#ifndef CONFIG_MMU
+		*(.text.fixup)
+		*(__ex_table)
+#endif
+#ifndef CONFIG_SMP_ON_UP
+		*(.alt.smp.init)
+#endif
+		*(.discard)
+		*(.discard.*)
+	}
+
+	. = XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR);
+
+	.head.text : {
+		_text = .;
+		HEAD_TEXT
+	}
+
+#ifdef CONFIG_ARM_KERNMEM_PERMS
+	. = ALIGN(1<<SECTION_SHIFT);
+#endif
+
+	.text : {			/* Real text segment		*/
+		_stext = .;		/* Text and read-only data	*/
+			IDMAP_TEXT
+			__exception_text_start = .;
+			*(.exception.text)
+			__exception_text_end = .;
+			IRQENTRY_TEXT
+			TEXT_TEXT
+			SCHED_TEXT
+			LOCK_TEXT
+			KPROBES_TEXT
+			*(.gnu.warning)
+			*(.glue_7)
+			*(.glue_7t)
+		. = ALIGN(4);
+		*(.got)			/* Global offset table		*/
+			ARM_CPU_KEEP(PROC_INFO)
+	}
+
+#ifdef CONFIG_DEBUG_RODATA
+	. = ALIGN(1<<SECTION_SHIFT);
+#endif
+	RO_DATA(PAGE_SIZE)
+
+	. = ALIGN(4);
+	__ex_table : AT(ADDR(__ex_table) - LOAD_OFFSET) {
+		__start___ex_table = .;
+#ifdef CONFIG_MMU
+		*(__ex_table)
+#endif
+		__stop___ex_table = .;
+	}
+
+#ifdef CONFIG_ARM_UNWIND
+	/*
+	 * Stack unwinding tables
+	 */
+	. = ALIGN(8);
+	.ARM.unwind_idx : {
+		__start_unwind_idx = .;
+		*(.ARM.exidx*)
+		__stop_unwind_idx = .;
+	}
+	.ARM.unwind_tab : {
+		__start_unwind_tab = .;
+		*(.ARM.extab*)
+		__stop_unwind_tab = .;
+	}
+#endif
+
+	NOTES
+
+	_etext = .;			/* End of text and rodata section */
+
+	/*
+	 * The vectors and stubs are relocatable code, and the
+	 * only thing that matters is their relative offsets
+	 */
+	__vectors_start = .;
+	.vectors 0 : AT(__vectors_start) {
+		*(.vectors)
+	}
+	. = __vectors_start + SIZEOF(.vectors);
+	__vectors_end = .;
+
+	__stubs_start = .;
+	.stubs 0x1000 : AT(__stubs_start) {
+		*(.stubs)
+	}
+	. = __stubs_start + SIZEOF(.stubs);
+	__stubs_end = .;
+
+	INIT_TEXT_SECTION(8)
+	.exit.text : {
+		ARM_EXIT_KEEP(EXIT_TEXT)
+	}
+	.init.proc.info : {
+		ARM_CPU_DISCARD(PROC_INFO)
+	}
+	.init.arch.info : {
+		__arch_info_begin = .;
+		*(.arch.info.init)
+		__arch_info_end = .;
+	}
+	.init.tagtable : {
+		__tagtable_begin = .;
+		*(.taglist.init)
+		__tagtable_end = .;
+	}
+#ifdef CONFIG_SMP_ON_UP
+	.init.smpalt : {
+		__smpalt_begin = .;
+		*(.alt.smp.init)
+		__smpalt_end = .;
+	}
+#endif
+	.init.pv_table : {
+		__pv_table_begin = .;
+		*(.pv_table)
+		__pv_table_end = .;
+	}
+	.init.data : {
+		INIT_SETUP(16)
+		INIT_CALLS
+		CON_INITCALL
+		SECURITY_INITCALL
+		INIT_RAM_FS
+	}
+
+#ifdef CONFIG_SMP
+	PERCPU_SECTION(L1_CACHE_BYTES)
+#endif
+
+	__data_loc = ALIGN(4);		/* location in binary */
+	. = PAGE_OFFSET + TEXT_OFFSET;
+
+	.data : AT(__data_loc) {
+		_data = .;		/* address in memory */
+		_sdata = .;
+
+		/*
+		 * first, the init task union, aligned
+		 * to an 8192 byte boundary.
+		 */
+		INIT_TASK_DATA(THREAD_SIZE)
+
+		. = ALIGN(PAGE_SIZE);
+		__init_begin = .;
+		INIT_DATA
+		ARM_EXIT_KEEP(EXIT_DATA)
+		. = ALIGN(PAGE_SIZE);
+		__init_end = .;
+
+		NOSAVE_DATA
+		CACHELINE_ALIGNED_DATA(L1_CACHE_BYTES)
+		READ_MOSTLY_DATA(L1_CACHE_BYTES)
+
+		/*
+		 * and the usual data section
+		 */
+		DATA_DATA
+		CONSTRUCTORS
+
+		_edata = .;
+	}
+	_edata_loc = __data_loc + SIZEOF(.data);
+
+#ifdef CONFIG_HAVE_TCM
+        /*
+	 * We align everything to a page boundary so we can
+	 * free it after init has commenced and TCM contents have
+	 * been copied to its destination.
+	 */
+	.tcm_start : {
+		. = ALIGN(PAGE_SIZE);
+		__tcm_start = .;
+		__itcm_start = .;
+	}
+
+	/*
+	 * Link these to the ITCM RAM
+	 * Put VMA to the TCM address and LMA to the common RAM
+	 * and we'll upload the contents from RAM to TCM and free
+	 * the used RAM after that.
+	 */
+	.text_itcm ITCM_OFFSET : AT(__itcm_start)
+	{
+		__sitcm_text = .;
+		*(.tcm.text)
+		*(.tcm.rodata)
+		. = ALIGN(4);
+		__eitcm_text = .;
+	}
+
+	/*
+	 * Reset the dot pointer, this is needed to create the
+	 * relative __dtcm_start below (to be used as extern in code).
+	 */
+	. = ADDR(.tcm_start) + SIZEOF(.tcm_start) + SIZEOF(.text_itcm);
+
+	.dtcm_start : {
+		__dtcm_start = .;
+	}
+
+	/* TODO: add remainder of ITCM as well, that can be used for data! */
+	.data_dtcm DTCM_OFFSET : AT(__dtcm_start)
+	{
+		. = ALIGN(4);
+		__sdtcm_data = .;
+		*(.tcm.data)
+		. = ALIGN(4);
+		__edtcm_data = .;
+	}
+
+	/* Reset the dot pointer or the linker gets confused */
+	. = ADDR(.dtcm_start) + SIZEOF(.data_dtcm);
+
+	/* End marker for freeing TCM copy in linked object */
+	.tcm_end : AT(ADDR(.dtcm_start) + SIZEOF(.data_dtcm)){
+		. = ALIGN(PAGE_SIZE);
+		__tcm_end = .;
+	}
+#endif
+
+	BSS_SECTION(0, 0, 0)
+	_end = .;
+
+	STABS_DEBUG
+}
+
+/*
+ * These must never be empty
+ * If you have to comment these two assert statements out, your
+ * binutils is too old (for other reasons as well)
+ */
+ASSERT((__proc_info_end - __proc_info_begin), "missing CPU support")
+ASSERT((__arch_info_end - __arch_info_begin), "no machine record defined")
+
+/*
+ * The HYP init code can't be more than a page long,
+ * and should not cross a page boundary.
+ * The above comment applies as well.
+ */
+ASSERT(__hyp_idmap_text_end - (__hyp_idmap_text_start & PAGE_MASK) <= PAGE_SIZE,
+	"HYP init code too big or misaligned")
diff --git a/arch/arm/kernel/vmlinux.lds.S b/arch/arm/kernel/vmlinux.lds.S
index 8b60fde..2c5b76e 100644
--- a/arch/arm/kernel/vmlinux.lds.S
+++ b/arch/arm/kernel/vmlinux.lds.S
@@ -84,11 +84,7 @@ SECTIONS
 		*(.discard.*)
 	}
 
-#ifdef CONFIG_XIP_KERNEL
-	. = XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR);
-#else
 	. = PAGE_OFFSET + TEXT_OFFSET;
-#endif
 	.head.text : {
 		_text = .;
 		HEAD_TEXT
@@ -152,14 +148,13 @@ SECTIONS
 
 	_etext = .;			/* End of text and rodata section */
 
-#ifndef CONFIG_XIP_KERNEL
-# ifdef CONFIG_ARM_KERNMEM_PERMS
+#ifdef CONFIG_ARM_KERNMEM_PERMS
 	. = ALIGN(1<<SECTION_SHIFT);
-# else
+#else
 	. = ALIGN(PAGE_SIZE);
-# endif
-	__init_begin = .;
 #endif
+	__init_begin = .;
+
 	/*
 	 * The vectors and stubs are relocatable code, and the
 	 * only thing that matters is their relative offsets
@@ -208,29 +203,21 @@ SECTIONS
 		__pv_table_end = .;
 	}
 	.init.data : {
-#ifndef CONFIG_XIP_KERNEL
 		INIT_DATA
-#endif
 		INIT_SETUP(16)
 		INIT_CALLS
 		CON_INITCALL
 		SECURITY_INITCALL
 		INIT_RAM_FS
 	}
-#ifndef CONFIG_XIP_KERNEL
 	.exit.data : {
 		ARM_EXIT_KEEP(EXIT_DATA)
 	}
-#endif
 
 #ifdef CONFIG_SMP
 	PERCPU_SECTION(L1_CACHE_BYTES)
 #endif
 
-#ifdef CONFIG_XIP_KERNEL
-	__data_loc = ALIGN(4);		/* location in binary */
-	. = PAGE_OFFSET + TEXT_OFFSET;
-#else
 #ifdef CONFIG_ARM_KERNMEM_PERMS
 	. = ALIGN(1<<SECTION_SHIFT);
 #else
@@ -238,7 +225,6 @@ SECTIONS
 #endif
 	__init_end = .;
 	__data_loc = .;
-#endif
 
 	.data : AT(__data_loc) {
 		_data = .;		/* address in memory */
@@ -250,15 +236,6 @@ SECTIONS
 		 */
 		INIT_TASK_DATA(THREAD_SIZE)
 
-#ifdef CONFIG_XIP_KERNEL
-		. = ALIGN(PAGE_SIZE);
-		__init_begin = .;
-		INIT_DATA
-		ARM_EXIT_KEEP(EXIT_DATA)
-		. = ALIGN(PAGE_SIZE);
-		__init_end = .;
-#endif
-
 		NOSAVE_DATA
 		CACHELINE_ALIGNED_DATA(L1_CACHE_BYTES)
 		READ_MOSTLY_DATA(L1_CACHE_BYTES)
-- 
1.7.9.5



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