ARCv3: Add ability to change size of the mapped kernel address space

This update add the ability to change the kernel address space from
1Gb up to 2Gb. Tested for HS5x/HS6x with MMUv6_32/MMUv6_48 and page
size=4K.

Author: xxkent

arch/arc/Kconfig

@@ -582,6 +582,20 @@ config LINUX_RAM_BASE
 	  cases (such as HSDK), Linux can't be linked at start of DDR, hence
 	  this option.
 	  This needs to match memory start address specified in Device Tree
+	  LINUX_RAM_BASE needs to match LINUX_RAM_BASE in dts file.
+
+config LINUX_MAP_SIZE
+        hex "Map size"
+        default "0x40000000"
+        help
+	  0x40000000 - 1Gb is the default size. You can cahnge it to
+	  0x80000000 - 2Gb to increase kernel space size.
+	  Don't setup it more than 0x6000000 for HS5x when ARC_KVADDR_SIZE==256.
+	  Don't setup it more than 0x5000000 for HS5x when ARC_KVADDR_SIZE==512.
+	  Don't setup it more than 0x80000000 for HS6x.
+	  LINUX_MAP_SIZE needs to match LINUX_RAM_SIZE in dts file.
+	  If you don't know what the above means, leave this setting default.
+	  ARC_KVADDR_SIZE also impacts to LINUX_MAP_SIZE
 
 config HIGHMEM
 	bool "High Memory Support"

arch/arc/include/asm/processor.h

@@ -90,17 +90,11 @@ extern unsigned long __get_wchan(struct task_struct *p);
 #define TASK_SIZE		0x60000000
 #define USER_KERNEL_GUTTER	0
 
-#define FIXADDR_START		(PAGE_OFFSET + PUD_SIZE)
-
 #define VMALLOC_START	(PAGE_OFFSET + 0x100000000000UL)
 #define VMALLOC_SIZE	(CONFIG_ARC_KVADDR_SIZE << 20)
 #define VMALLOC_END	(VMALLOC_START + VMALLOC_SIZE)
 
-/*
- * How much memory to map before dtb parsing and paging init.
- * 1Gb is selected to fit in one PUD for any ARCv3 MMU configurations.
- */
-#define EARLY_MAP_SIZE	(1 << 30)
+#define FIXADDR_START	(PAGE_OFFSET + CONFIG_LINUX_MAP_SIZE)
 
 #elif defined(CONFIG_ARC_MMU_V6_32)
 /*
@@ -117,17 +111,11 @@ extern unsigned long __get_wchan(struct task_struct *p);
 #define TASK_SIZE		0x60000000
 #define USER_KERNEL_GUTTER	0
 
-#define VMALLOC_START	(PAGE_OFFSET + PUD_SIZE)
+#define VMALLOC_START	(PAGE_OFFSET + CONFIG_LINUX_MAP_SIZE)
 #define VMALLOC_SIZE	(CONFIG_ARC_KVADDR_SIZE << 20)
 #define VMALLOC_END	(VMALLOC_START + VMALLOC_SIZE)
 
-#define FIXADDR_START	(VMALLOC_START + VMALLOC_SIZE)
-
-/*
- * How much memory to map before dtb parsing and paging init.
- * 1Gb is selected to fit in one PUD for any ARCv3 MMU configurations.
- */
-#define EARLY_MAP_SIZE	(1 << 30)
+#define FIXADDR_START	(0xFF000000)
 
 #else
 

arch/arc/kernel/head.S

@@ -89,18 +89,20 @@
 ;
 ; Out:
 ;       All registers are clobbered.
-.macro BUILD_PAGE_TABLE, link_addr, phy_addr, link_end, pgd, pud, pmd, cur, tmp
+.macro BUILD_PAGE_TABLE, link_addr, phy_addr, link_end, pgd, pud, pmd, cur, tmp, val, foo
 
 ; FIXME: we need asserts about kernel size <= allocated size
 ; FIXME: we need a better way to generalize this
 #if defined(CONFIG_ARC_MMU_V6_48) && defined(CONFIG_ARC_PAGE_SIZE_4K)
 
-; Two-level page table, PGD + PUD
+; Three-level page table, PGD + PUD + PMD
 #define BUILD_PGD_ENTRY BUILD_PAGE_TABLE_ENTRY \pgd, \link_addr, \pud, \cur, \tmp, PTRS_PER_PGD, PGDIR_SHIFT, PAGE_KERNEL
-#define BUILD_PUD_ENTRY BUILD_PAGE_TABLE_ENTRY \pud, \link_addr, \phy_addr, \cur, \tmp, PTRS_PER_PUD, PUD_SHIFT, PAGE_KERNEL_BLK
-#define BUILD_PMD_ENTRY
-#define ENTRY_SIZE	PUD_SIZE
-#define ENTRY_LABEL	.Lbuild_pud_entry\@
+#define BUILD_PUD_ENTRY BUILD_PAGE_TABLE_ENTRY \pud, \link_addr, \pmd, \cur, \tmp, PTRS_PER_PUD, PUD_SHIFT, PAGE_KERNEL
+#define BUILD_PMD_ENTRY BUILD_PAGE_TABLE_ENTRY \pmd, \link_addr, \phy_addr, \cur, \tmp, PTRS_PER_PMD, PMD_SHIFT, PAGE_KERNEL_BLK
+#define ENTRY_SIZE	PMD_SIZE
+#define ENTRY_LABEL	.Lbuild_pmd_entry\@
+#define NEXT_SIZE	PUD_SIZE
+#define ENTRY_LABEL_NEXT	.Lbuild_pud_entry\@
 
 #elif defined(CONFIG_ARC_MMU_V6_48) && defined(CONFIG_ARC_PAGE_SIZE_16K)
 
@@ -110,6 +112,8 @@
 #define BUILD_PMD_ENTRY BUILD_PAGE_TABLE_ENTRY \pmd, \link_addr, \phy_addr, \cur, \tmp, PTRS_PER_PMD, PMD_SHIFT, PAGE_KERNEL_BLK
 #define ENTRY_SIZE	PMD_SIZE
 #define ENTRY_LABEL	.Lbuild_pmd_entry\@
+#define NEXT_SIZE	PUD_SIZE
+#define ENTRY_LABEL_NEXT	.Lbuild_pud_entry\@
 
 #elif defined(CONFIG_ARC_MMU_V6_48) && defined(CONFIG_ARC_PAGE_SIZE_64K) || defined(CONFIG_ARC_MMU_V6_52) || defined(CONFIG_ARC_MMU_V6_32)
 
@@ -119,9 +123,14 @@
 #define BUILD_PMD_ENTRY BUILD_PAGE_TABLE_ENTRY \pmd, \link_addr, \phy_addr, \cur, \tmp, PTRS_PER_PMD, PMD_SHIFT, PAGE_KERNEL_BLK
 #define ENTRY_SIZE	PMD_SIZE
 #define ENTRY_LABEL	.Lbuild_pmd_entry\@
+#define NEXT_SIZE	PGDIR_SIZE
+#define ENTRY_LABEL_NEXT	.Lbuild_pgd_entry\@
 
 #endif
 
+	ADDR	\val, \link_addr, NEXT_SIZE
+	MOVR	\foo, \pmd
+
 .Lbuild_pgd_entry\@:
 	BUILD_PGD_ENTRY
 
@@ -136,15 +145,26 @@
 	ADDR	\link_addr, \link_addr, ENTRY_SIZE
 
 	; All link addresses are in
-	CMPR	\link_end, \link_addr
-	ble	.Lbuild_end\@
+	CMPR	\link_addr, \link_end
+	bge		.Lbuild_end\@
+	CMPR	\link_addr, \val
+	bge.d	.Linc\@
+	ADDR	\foo, \foo, 0x8
 	b	ENTRY_LABEL
+
+.Linc\@:
+	MOVR	\pmd, \foo
+	ADDR	\val, \foo, NEXT_SIZE
+	b 		ENTRY_LABEL_NEXT
+
 .Lbuild_end\@:
 #undef BUILD_PGD_ENTRY
 #undef BUILD_PUD_ENTRY
 #undef BUILD_PMD_ENTRY
 #undef ENTRY_SIZE
 #undef ENTRY_LABEL
+#undef NEXT_SIZE
+#undef ENTRY_LABEL_NEXT
 .endm
 
 ; Create page table with 1:1 mapping in given table pointers.
@@ -196,7 +216,7 @@
 	SUBR	r8, r8, r10
 	ADDR	r8, r8, r11
 
-	BUILD_PAGE_TABLE r3, r4, r5, r6, r7, r8, r9, r10
+	BUILD_PAGE_TABLE r3, r4, r5, r6, r7, r8, r9, r10, r11, r12
 .endm
 
 ; Create page table with virt to phy mapping in given addresses.
@@ -212,8 +232,8 @@
 	MOVI    r3, PAGE_OFFSET
 	; phy_addr <- CONFIG_LINUX_LINK_BASE
 	MOVI	r4, CONFIG_LINUX_LINK_BASE
-	; link_end <- EARLY_MAP_SIZE , see processor.h
-	MOVI	r5, (PAGE_OFFSET + EARLY_MAP_SIZE)
+	; link_end <- CONFIG_LINUX_MAP_SIZE , see processor.h
+	MOVI	r5, (PAGE_OFFSET + CONFIG_LINUX_MAP_SIZE)
 
 	; pgd <- __pa(tbl_pg_dir)
 	MOVA	r6, \tbl_pg_dir
@@ -230,7 +250,7 @@
 	SUBR	r8, r8, r3
 	ADDR	r8, r8, r4
 
-	BUILD_PAGE_TABLE r3, r4, r5, r6, r7, r8, r9, r10
+	BUILD_PAGE_TABLE r3, r4, r5, r6, r7, r8, r9, r10, r11, r12
 .endm
 
 ; Enable MMU and jump into virtual address space.

arch/arc/mm/init.c

@@ -19,13 +19,13 @@
 
 pgd_t swapper_pg_dir[PTRS_PER_PGD] __page_aligned_bss;
 pud_t swapper_pud[PTRS_PER_PUD] __page_aligned_bss;
-pmd_t swapper_pmd[PTRS_PER_PMD] __page_aligned_bss;
+pmd_t swapper_pmd[2*PTRS_PER_PMD] __page_aligned_bss; // BUG_ON! swapper_pmd[PTRS_PER_PMD] __page_aligned_bss
 
 #if defined(CONFIG_ISA_ARCV3)
 /* Used for early memory map in head.S for ARCv3 */
 pgd_t early_pg_dir[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE);
 pud_t early_pud[PTRS_PER_PUD] __initdata __aligned(PAGE_SIZE);
-pmd_t early_pmd[PTRS_PER_PMD] __initdata __aligned(PAGE_SIZE);
+pmd_t early_pmd[2*PTRS_PER_PMD] __initdata __aligned(PAGE_SIZE); // BUG_ON! early_pmd[PTRS_PER_PMD] __aligned(PAGE_SIZE)
 #endif
 
 char empty_zero_page[PAGE_SIZE] __aligned(PAGE_SIZE);

arch/arc/mm/tlb-arcv3.c

@@ -160,10 +160,6 @@ void __init early_fixmap_init(void)
 	BUILD_BUG_ON(pmd_index(FIXADDR_START) != \
 		     pmd_index(FIXADDR_START + FIXADDR_SIZE));
 
-	/* FIXADDR space must not overlap early mapping. */
-	BUILD_BUG_ON(FIXADDR_START >= PAGE_OFFSET && \
-		     FIXADDR_START < PAGE_OFFSET + EARLY_MAP_SIZE);
-
 	addr = FIXADDR_START;
 
 	pgd = (pgd_t *) __va(arc_mmu_rtp_get_addr(1));
@@ -240,26 +236,26 @@ void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t prot)
 int arc_map_kernel_in_mm(struct mm_struct *mm)
 {
 	unsigned long addr = PAGE_OFFSET;
-	unsigned long end = PAGE_OFFSET + PUD_SIZE;
+	unsigned long end = PAGE_OFFSET + CONFIG_LINUX_MAP_SIZE;
 	pgd_t *pgd;
 	p4d_t *p4d;
 	pud_t *pud;
 	pmd_t *pmd;
 
-	pgd = pgd_offset(mm, addr);
-	if (pgd_none(*pgd) || !pgd_present(*pgd))
-		return 1;
+	do {
+		pgprot_t prot = PAGE_KERNEL_BLK;
 
-	p4d = p4d_offset(pgd, addr);
-	if (p4d_none(*p4d) || !p4d_present(*p4d))
-		return 1;
+		pgd = pgd_offset(mm, addr);
+		if (pgd_none(*pgd) || !pgd_present(*pgd))
+			return 1;
 
-	pud = pud_offset(p4d, addr);
-	if (pud_none(*pud) || !pud_present(*pud))
-		return 1;
+		p4d = p4d_offset(pgd, addr);
+		if (p4d_none(*p4d) || !p4d_present(*p4d))
+			return 1;
 
-	do {
-		pgprot_t prot = PAGE_KERNEL_BLK;
+		pud = pud_offset(p4d, addr);
+		if (pud_none(*pud) || !pud_present(*pud))
+			return 1;
 
 		pmd = pmd_offset(pud, addr);
 		if (!pmd_none(*pmd) || pmd_present(*pmd))
@@ -285,12 +281,25 @@ void arc_paging_init(void)
 	idx = pud_index(PAGE_OFFSET);
 	swapper_pud[idx] = pfn_pud(virt_to_pfn(swapper_pmd), PAGE_TABLE);
 	ptw_flush(&swapper_pud[idx]);
+
+	if(CONFIG_LINUX_MAP_SIZE > 0x40000000) { //Mapping from 1Gb..2Gb
+		idx = pud_index(PAGE_OFFSET + 0x40000000);
+		swapper_pud[idx] = pfn_pud(virt_to_pfn(&swapper_pmd[PTRS_PER_PMD]), PAGE_TABLE);
+		ptw_flush(&swapper_pud[idx]);
+	}
+
 #elif CONFIG_PGTABLE_LEVELS == 3
 	unsigned int idx;
 
 	idx = pgd_index(PAGE_OFFSET);
 	swapper_pg_dir[idx] = pfn_pgd(virt_to_pfn(swapper_pmd), PAGE_TABLE);
 	ptw_flush(&swapper_pg_dir[idx]);
+
+	if(CONFIG_LINUX_MAP_SIZE > 0x40000000) { //Mapping from 1Gb..2Gb
+		idx = pgd_index(PAGE_OFFSET + 0x40000000);
+		swapper_pg_dir[idx] = pfn_pgd(virt_to_pfn(&swapper_pmd[PTRS_PER_PMD]), PAGE_TABLE);
+		ptw_flush(&swapper_pg_dir[idx]);
+	}
 #endif
 
 	arc_map_kernel_in_mm(&init_mm);
@@ -309,8 +318,6 @@ void arc_mmu_init(void)
 	 */
 	/* It is always true when PAGE_OFFSET is aligned to pmd. */
 	BUILD_BUG_ON(pmd_index(PAGE_OFFSET) != 0);
-	/* And size of early mapping is lower then PUD. */
-	BUILD_BUG_ON(EARLY_MAP_SIZE > PUD_SIZE);
 
 	if (mmuinfo.pg_sz_k != TO_KB(PAGE_SIZE))
 		panic("MMU pg size != PAGE_SIZE (%luk)\n", TO_KB(PAGE_SIZE));