kexec: arm64: purgatory: cache support

This patch adds support to enable/disable d-cache, which can be used for faster purgatory sha256 verification.

We are supporting only 4K and 64K page sizes. This code will not work if a hardware is not supporting at least one of these page sizes. Therefore, D-cache is disabled by default and enabled only when "enable-dcache" is passed to the kexec().
Since this is an identity mapped system, so VA_BITS will be same as max PA bits supported. If VA_BITS <= 42 for 64K and <= 39 for 4K then only one level of page table will be there with block descriptor entries. Otherwise, For 4K mapping, TTBR points to level 0 lookups, which will have only table entries pointing to a level 1 lookup. Level 1 will have only block entries which will map 1GB block. For 64K mapping, TTBR points to level 1 lookups, which will have only table entries pointing to a level 2 lookup. Level 2 will have only block entries which will map 512MB block. If UART base address and RAM addresses are not at least 1GB and 512MB apart for 4K and 64K respectively, then mapping result could be unpredictable. In that case we need to support one more level of granularity, but until someone needs that keep it like this only.
We can not allocate dynamic memory in purgatory. Therefore we keep page table allocation size fixed as (3 * MAX_PAGE_SIZE). (page_table) points to first level (having only table entries) and (page_table + MAX_PAGE_SIZE) points to table at next level (having block entries). If index for RAM area and UART area in first table is not same, then we will need another next level table which will be located at (page_table + 2 * MAX_PAGE_SIZE).

Signed-off-by Pratyush Anand <[email protected]>

---
  purgatory/arch/arm64/Makefile    |   2 +
  purgatory/arch/arm64/cache-asm.S | 228 +++++++++++++++++++++++++++
  purgatory/arch/arm64/cache.c     | 333 +++++++++++++++++++++++++++++++++++++++
  purgatory/arch/arm64/cache.h     |  83 ++++++++++
  4 files changed, 646 insertions(+)

create mode 100644 purgatory/arch/arm64/cache-asm.S create mode 100644 purgatory/arch/arm64/cache.c create mode 100644 purgatory/arch/arm64/cache.h

purgatory/arch/arm64/Makefile +2 -0

index 636abeab17b2..0f80f8165d90 100644
@@ -11,6 +11,8 @@ arm64_PURGATORY_EXTRA_CFLAGS = \
 
  arm64_PURGATORY_SRCS += \
  	purgatory/arch/arm64/entry.S \
+	purgatory/arch/arm64/cache-asm.S \
+	purgatory/arch/arm64/cache.c \
  	purgatory/arch/arm64/purgatory-arm64.c
 
  dist += \

purgatory/arch/arm64/cache-asm.S new file +228 -0

new file mode 100644
index 000000000000..8ef4083343f1
@@ -0,0 +1,228 @@
+/*
+ * Some of the routines have been copied from Linux Kernel, therefore
+ * copying the license as well.
+ *
+ * Copyright (C) 2001 Deep Blue Solutions Ltd.
+ * Copyright (C) 2012 ARM Ltd.
+ * Copyright (C) 2015 Pratyush Anand <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "cache.h"
+
+/*
+ * 	dcache_line_size - get the minimum D-cache line size from the CTR register.
+ */
+	.macro	dcache_line_size, reg, tmp
+	mrs	\tmp, ctr_el0			// read CTR
+	ubfm	\tmp, \tmp, #16, #19		// cache line size encoding
+	mov	\reg, #4			// bytes per word
+	lsl	\reg, \reg, \tmp		// actual cache line size
+	.endm
+
+/*
+ *	inval_cache_range(start, end)
+ *	- x0 - start	- start address of region
+ *	- x1 - end	- end address of region
+ */
+.globl inval_cache_range
+inval_cache_range:
+	dcache_line_size x2, x3
+	sub	x3, x2, #1
+	tst	x1, x3				// end cache line aligned?
+	bic	x1, x1, x3
+	b.eq	1f
+	dc	civac, x1			// clean & invalidate D / U line
+1:	tst	x0, x3				// start cache line aligned?
+	bic	x0, x0, x3
+	b.eq	2f
+	dc	civac, x0			// clean & invalidate D / U line
+	b	3f
+2:	dc	ivac, x0			// invalidate D / U line
+3:	add	x0, x0, x2
+	cmp	x0, x1
+	b.lo	2b
+	dsb	sy
+	ret
+/*
+ *	flush_dcache_range(start, end)
+ *	- x0 - start	- start address of region
+ *	- x1 - end	- end address of region
+ *
+ */
+.globl flush_dcache_range
+flush_dcache_range:
+	dcache_line_size x2, x3
+	sub	x3, x2, #1
+	bic	x0, x0, x3
+1:	dc	civac, x0			// clean & invalidate D line / unified line
+	add	x0, x0, x2
+	cmp	x0, x1
+	b.lo	1b
+	dsb	sy
+	ret
+
+/*
+ *	invalidate_tlbs_el1()
+ */
+.globl invalidate_tlbs_el1
+invalidate_tlbs_el1:
+	dsb	nshst
+	tlbi	vmalle1
+	dsb	nsh
+	isb
+	ret
+
+/*
+ *	invalidate_tlbs_el2()
+ */
+.globl invalidate_tlbs_el2
+invalidate_tlbs_el2:
+	dsb	nshst
+	tlbi	alle2
+	dsb	nsh
+	isb
+	ret
+
+/*
+ *	invalidate_tlbs_el3()
+ */
+.globl invalidate_tlbs_el3
+invalidate_tlbs_el3:
+	dsb	nshst
+	tlbi	alle3
+	dsb	nsh
+	isb
+	ret
+
+/*
+ * 	get_mm_feature_reg0_val - Get information about supported MM
+ * 	features
+ */
+.globl get_mm_feature_reg0_val
+get_mm_feature_reg0_val:
+	mrs	x0, ID_AA64MMFR0_EL1
+	ret
+
+/*
+ * 	get_current_el - Get information about current exception level
+ */
+.globl get_current_el
+get_current_el:
+	mrs 	x0, CurrentEL
+	lsr	x0, x0, #2
+	ret
+
+/*
+ * 	invalidate_icache - Invalidate I-cache
+ */
+.globl invalidate_icache
+invalidate_icache:
+	ic	iallu
+	dsb	nsh
+	isb
+	ret
+
+/*
+ * 	set_mair_tcr_ttbr_sctlr_el1(page_table, tcr_flags) - sets MAIR, TCR , TTBR and SCTLR registers
+ * 	x0 - page_table - Page Table Base
+ * 	x1 - tcr_flags - TCR Flags to be set
+ */
+.globl set_mair_tcr_ttbr_sctlr_el1
+set_mair_tcr_ttbr_sctlr_el1:
+	ldr	x2, =MEMORY_ATTRIBUTES
+	msr	mair_el1, x2
+	msr	tcr_el1, x1
+	msr	ttbr0_el1, x0
+	isb
+	mrs	x0, sctlr_el1
+	ldr	x3, =SCTLR_ELx_FLAGS
+	orr	x0, x0, x3
+	msr	sctlr_el1, x0
+	isb
+	ret
+
+/*
+ * 	set_mair_tcr_ttbr_sctlr_el2(page_table, tcr_flags) - sets MAIR, TCR , TTBR and SCTLR registers
+ * 	x0 - page_table - Page Table Base
+ * 	x1 - tcr_flags - TCR Flags to be set
+ */
+.globl set_mair_tcr_ttbr_sctlr_el2
+set_mair_tcr_ttbr_sctlr_el2:
+	ldr	x2, =MEMORY_ATTRIBUTES
+	msr	mair_el2, x2
+	msr	tcr_el2, x1
+	msr	ttbr0_el2, x0
+	isb
+	mrs	x0, sctlr_el2
+	ldr	x3, =SCTLR_ELx_FLAGS
+	orr	x0, x0, x3
+	msr	sctlr_el2, x0
+	isb
+	ret
+
+/*
+ * 	set_mair_tcr_ttbr_sctlr_el3(page_table, tcr_flags) - sets MAIR, TCR , TTBR and SCTLR registers
+ * 	x0 - page_table - Page Table Base
+ * 	x1 - tcr_flags - TCR Flags to be set
+ */
+.globl set_mair_tcr_ttbr_sctlr_el3
+set_mair_tcr_ttbr_sctlr_el3:
+	ldr	x2, =MEMORY_ATTRIBUTES
+	msr	mair_el3, x2
+	msr	tcr_el3, x1
+	msr	ttbr0_el3, x0
+	isb
+	mrs	x0, sctlr_el3
+	ldr	x3, =SCTLR_ELx_FLAGS
+	orr	x0, x0, x3
+	msr	sctlr_el3, x0
+	isb
+	ret
+
+/*
+ * reset_sctlr_el1 - disables cache and mmu
+ */
+.globl reset_sctlr_el1
+reset_sctlr_el1:
+	mrs	x0, sctlr_el1
+	bic	x0, x0, #SCTLR_ELx_C
+	bic	x0, x0, #SCTLR_ELx_M
+	msr	sctlr_el1, x0
+	isb
+	ret
+
+/*
+ * reset_sctlr_el2 - disables cache and mmu
+ */
+.globl reset_sctlr_el2
+reset_sctlr_el2:
+	mrs	x0, sctlr_el2
+	bic	x0, x0, #SCTLR_ELx_C
+	bic	x0, x0, #SCTLR_ELx_M
+	msr	sctlr_el2, x0
+	isb
+	ret
+
+/*
+ * reset_sctlr_el3 - disables cache and mmu
+ */
+.globl reset_sctlr_el3
+reset_sctlr_el3:
+	mrs	x0, sctlr_el3
+	bic	x0, x0, #SCTLR_ELx_C
+	bic	x0, x0, #SCTLR_ELx_M
+	msr	sctlr_el3, x0
+	isb
+	ret

purgatory/arch/arm64/cache.c new file +93 -0

new file mode 100644
index 000000000000..86f6ab1bb81e
@@ -0,0 +1,333 @@
+/*
+ * Copyright (C) 2015 Pratyush Anand <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/* We are supporting only 4K and 64K page sizes. This code will not work if
+ * a hardware is not supporting at least one of these page sizes.
+ * Therefore, D-cache is disabled by default and enabled only when
+ * "enable-dcache" is passed to the kexec().
+ * Since this is an identity mapped system, so VA_BITS will be same as max
+ * PA bits supported. If VA_BITS <= 42 for 64K and <= 39 for 4K then only
+ * one level of page table will be there with block descriptor entries.
+ * Otherwise, For 4K mapping, TTBR points to level 0 lookups, which will
+ * have only table entries pointing to a level 1 lookup. Level 1 will have
+ * only block entries which will map 1GB block.For 64K mapping, TTBR points
+ * to level 1 lookups, which will have only table entries pointing to a
+ * level 2 lookup. Level 2 will have only block entries which will map
+ * 512MB block. If UART base address and RAM addresses are not at least 1GB
+ * and 512MB apart for 4K and 64K respectively, then mapping result could
+ * be unpredictable. In that case we need to support one more level of
+ * granularity, but until someone needs that keep it like this only.
+ * We can not allocate dynamic memory in purgatory. Therefore we keep page
+ * table allocation size fixed as (3 * MAX_PAGE_SIZE). (page_table) points
+ * to first level (having only table entries) and (page_table +
+ * MAX_PAGE_SIZE) points to table at next level (having block entries). If
+ * index for RAM area and UART area in first table is not same, then we
+ * will need another next level table which will be located at (page_table
+ * + 2 * MAX_PAGE_SIZE).
+ */
+
+#include <stdint.h>
+#include <string.h>
+#include <purgatory.h>
+#include "cache.h"
+
+static uint64_t page_shift;
+static uint64_t pgtable_level;
+static uint64_t va_bits;
+
+static uint64_t page_table[PAGE_TABLE_SIZE / sizeof(uint64_t)] __attribute__ ((aligned (MAX_PAGE_SIZE))) = { };
+static uint64_t page_table_used;
+
+#define PAGE_SIZE	(1 << page_shift)
+/*
+ *	is_4k_page_supported - return true if 4k page is supported else
+ *	false
+ */
+static int is_4k_page_supported(void)
+{
+	return ((get_mm_feature_reg0_val() & ID_AA64MMFR0_TGRAN4_MASK) ==
+			ID_AA64MMFR0_TGRAN4_SUPPORTED);
+}
+
+/*
+ *	is_64k_page_supported - return true if 64k page is supported else
+ *	false
+ */
+static int is_64k_page_supported(void)
+{
+	return ((get_mm_feature_reg0_val() & ID_AA64MMFR0_TGRAN64_MASK) ==
+			ID_AA64MMFR0_TGRAN64_SUPPORTED);
+}
+
+/*
+ *	get_ips_bits - return supported IPS bits
+ */
+static uint64_t get_ips_bits(void)
+{
+	return ((get_mm_feature_reg0_val() & ID_AA64MMFR0_PARANGE_MASK) >>
+			ID_AA64MMFR0_PARANGE_SHIFT);
+}
+
+/*
+ *	get_va_bits - return supported VA bits (For identity mapping VA = PA)
+ */
+static uint64_t get_va_bits(void)
+{
+	uint64_t ips = get_ips_bits();
+
+	switch(ips) {
+	case ID_AA64MMFR0_PARANGE_48:
+		return 48;

purgatory/arch/arm64/cache.c new file +41 -0

+	}
+}
+
+/*
+ *	get_section_shift - get block shift for supported page size
+ */
+static uint64_t get_section_shift(void)
+{
+	if (page_shift == 16)
+		return 29;
+	else if(page_shift == 12)
+		return 30;
+	else
+		return 0;
+}
+
+/*
+ *	get_section_mask - get section mask for supported page size
+ */
+static uint64_t get_section_mask(void)
+{
+	if (page_shift == 16)
+		return 0x1FFF;
+	else if(page_shift == 12)
+		return 0x1FF;
+	else
+		return 0;
+}
+
+/*
+ *	get_pgdir_shift - get pgdir shift for supported page size
+ */
+static uint64_t get_pgdir_shift(void)
+{
+	if (page_shift == 16)
+		return 42;
+	else if(page_shift == 12)
+		return 39;
+	else
+		return 0;
+}

purgatory/arch/arm64/cache.c new file +17 -0

+}
+/*
+ *	create_identity_mapping(start, end, flags)
+ *	start		- start address
+ *	end		- end address
+ *	flags 		- MMU Flags for Normal or Device type memory
+ */
+static void create_identity_mapping(uint64_t start, uint64_t end,
+					uint64_t flags)
+{
+	uint32_t sec_shift, pgdir_shift, sec_mask;
+	uint64_t desc, s1, e1, s2, e2;
+	uint64_t *table2;
+
+	s1 = start;
+	e1 = end;
+

purgatory/arch/arm64/cache.c new file +42 -0

+				table2 = &page_table[(++page_table_used *
+						MAX_PAGE_SIZE) /
+						sizeof(uint64_t)];
+				desc = (uint64_t)table2 | PMD_TYPE_TABLE;
+				page_table[s1] = desc;
+			} else {
+				table2 = (uint64_t *)(page_table[s1] &
+						~PMD_TYPE_MASK);
+			}
+			s1++;
+			s2 = start >> sec_shift;
+			s2 &= sec_mask;
+			e2 = end >> sec_shift;
+			e2 &= sec_mask;
+			do {
+				desc = s2 << sec_shift;
+				desc |= flags;
+				table2[s2] = desc;
+				s2++;
+			} while (s2 <= e2);
+		} while (s1 <= e1);
+	}
+}
+
+/*
+ *	enable_mmu_dcache: Enable mmu and D-cache in sctlr_el1
+ */
+static void enable_mmu_dcache(void)
+{
+	uint64_t tcr_flags = TCR_FLAGS | TCR_T0SZ(va_bits);
+
+	switch(page_shift) {
+	case 16:
+		tcr_flags |= TCR_TG0_64K;
+		break;
+	case 12:
+		tcr_flags |= TCR_TG0_4K;
+		break;
+	default:
+		printf("page shift not supported\n");
+		return;
+	}

purgatory/arch/arm64/cache.c new file +66 -0

+		invalidate_tlbs_el3();
+		tcr_flags |= (get_ips_bits() << TCR_IPS_EL3_SHIFT);
+		set_mair_tcr_ttbr_sctlr_el3((uint64_t)page_table, tcr_flags);
+		break;
+	case 2:
+		invalidate_tlbs_el2();
+		tcr_flags |= (get_ips_bits() << TCR_IPS_EL2_SHIFT);
+		set_mair_tcr_ttbr_sctlr_el2((uint64_t)page_table, tcr_flags);
+		break;
+	case 1:
+		invalidate_tlbs_el1();
+		tcr_flags |= (get_ips_bits() << TCR_IPS_EL1_SHIFT);
+		set_mair_tcr_ttbr_sctlr_el1((uint64_t)page_table, tcr_flags);
+		break;
+	default:
+		return;
+	}
+	invalidate_icache();
+}
+
+/*
+ *	enable_dcache: Enable D-cache and set appropriate attributes
+ *	ram_start - Start address of RAM
+ *	ram_end - End address of RAM
+ *	uart_base - Base address of uart
+ */
+int enable_dcache(uint64_t ram_start, uint64_t ram_end, uint64_t uart_base)
+{
+	va_bits = get_va_bits();
+
+	page_table_used = 0;
+	if (is_64k_page_supported()) {
+		page_shift = 16;
+		if (va_bits <= 42)
+			pgtable_level = 1;
+		else
+			pgtable_level = 2;
+	} else if (is_4k_page_supported()) {
+		page_shift = 12;
+		if (va_bits <= 39)
+			pgtable_level = 1;
+		else
+			pgtable_level = 2;
+	} else {
+		printf("Valid Page Granule not supported by hardware\n");
+		return -1;
+	}
+	init_page_table();
+	create_identity_mapping(ram_start, ram_end, MM_MMUFLAGS_NORMAL);
+	printf("Normal identity mapping created from %lx to %lx\n",
+			ram_start, ram_end);
+	if (uart_base) {
+		create_identity_mapping((uint64_t)uart_base,
+					(uint64_t)uart_base + PAGE_SIZE,
+					MM_MMUFLAGS_DEVICE);
+		printf("Device identity mapping created from %lx to %lx\n",
+				(uint64_t)uart_base,
+				(uint64_t)uart_base + PAGE_SIZE);
+	}
+	enable_mmu_dcache();
+	printf("Cache Enabled\n");
+
+	return 0;
+}
+
+/*

purgatory/arch/arm64/cache.c new file +13 -0

+	case 2:
+		reset_sctlr_el2();
+		break;
+	case 1:
+		reset_sctlr_el1();
+		break;
+	default:
+		return;
+	}
+	invalidate_icache();
+	flush_dcache_range(ram_start, ram_end);
+	printf("Cache Disabled\n");
+}

purgatory/arch/arm64/cache.h new file +26 -0

new file mode 100644
index 000000000000..34d779831607
@@ -0,0 +1,83 @@
+#ifndef	__CACHE_H__
+#define __CACHE_H__
+
+#define MT_DEVICE_NGNRNE	0
+#define MT_DEVICE_NGNRE		1
+#define MT_DEVICE_GRE		2
+#define MT_NORMAL_NC		3
+#define MT_NORMAL		4
+
+#ifndef __ASSEMBLER__
+
+#define MAX_PAGE_SIZE		0x10000
+#define PAGE_TABLE_SIZE		(3 * MAX_PAGE_SIZE)
+#define ID_AA64MMFR0_TGRAN64_SHIFT	24
+#define ID_AA64MMFR0_TGRAN4_SHIFT	28
+#define ID_AA64MMFR0_TGRAN64_MASK	(0xFUL << ID_AA64MMFR0_TGRAN64_SHIFT)
+#define ID_AA64MMFR0_TGRAN4_MASK	(0xFUL << ID_AA64MMFR0_TGRAN4_SHIFT)
+#define ID_AA64MMFR0_TGRAN64_SUPPORTED	0x0
+#define ID_AA64MMFR0_TGRAN4_SUPPORTED	0x0
+#define ID_AA64MMFR0_PARANGE_SHIFT	0
+#define ID_AA64MMFR0_PARANGE_MASK	(0xFUL << ID_AA64MMFR0_PARANGE_SHIFT)
+#define ID_AA64MMFR0_PARANGE_48		0x5
+#define ID_AA64MMFR0_PARANGE_44		0x4
+#define ID_AA64MMFR0_PARANGE_42		0x3
+#define ID_AA64MMFR0_PARANGE_40		0x2
+#define ID_AA64MMFR0_PARANGE_36		0x1

purgatory/arch/arm64/cache.h new file +37 -0

+#define TCR_T0SZ(x)		((unsigned long)(64 - (x)) << 0)
+#define TCR_FLAGS (TCR_SHARED_NONE | TCR_ORGN_WBWA | TCR_IRGN_WBWA)
+
+#define PMD_TYPE_SECT		(1UL << 0)
+#define PMD_TYPE_TABLE		(3UL << 0)
+#define PMD_TYPE_MASK		0x3
+#define PMD_SECT_AF		(1UL << 10)
+#define PMD_ATTRINDX(t)		((unsigned long)(t) << 2)
+#define PMD_FLAGS_NORMAL	(PMD_TYPE_SECT | PMD_SECT_AF)
+#define PMD_SECT_PXN		(1UL << 53)
+#define PMD_SECT_UXN		(1UL << 54)
+#define PMD_FLAGS_DEVICE	(PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_PXN | PMD_SECT_UXN)
+#define MM_MMUFLAGS_NORMAL	PMD_ATTRINDX(MT_NORMAL) | PMD_FLAGS_NORMAL
+#define MM_MMUFLAGS_DEVICE	PMD_ATTRINDX(MT_DEVICE_NGNRE) | PMD_FLAGS_DEVICE
+
+void disable_dcache(uint64_t ram_start, uint64_t ram_end);
+int enable_dcache(uint64_t ram_start, uint64_t ram_end, uint64_t uart_base);
+uint64_t get_mm_feature_reg0_val(void);
+void inval_cache_range(uint64_t start, uint64_t end);
+void flush_dcache_range(uint64_t start, uint64_t end);
+uint64_t get_current_el(void);
+void set_mair_tcr_ttbr_sctlr_el1(uint64_t page_table, uint64_t tcr_flags);
+void set_mair_tcr_ttbr_sctlr_el2(uint64_t page_table, uint64_t tcr_flags);
+void set_mair_tcr_ttbr_sctlr_el3(uint64_t page_table, uint64_t tcr_flags);
+void invalidate_tlbs_el1(void);
+void invalidate_tlbs_el2(void);
+void invalidate_tlbs_el3(void);
+void invalidate_icache(void);
+void reset_sctlr_el1(void);
+void reset_sctlr_el2(void);
+void reset_sctlr_el3(void);
+#else
+#define MEMORY_ATTRIBUTES	((0x00 << (MT_DEVICE_NGNRNE*8)) | \
+				(0x04 << (MT_DEVICE_NGNRE*8)) | \
+				(0x0C << (MT_DEVICE_GRE*8)) | \
+				(0x44 << (MT_NORMAL_NC*8)) | \
+				(0xFF << (MT_NORMAL*8)))

purgatory/arch/arm64/cache.c line 103

Quoted 2 lines

purgatory/arch/arm64/cache.c new file +2 -0

+	default:
+		return 32;

AA64MMFR0_PRANGE_32, instead of 'default', should explicitly be used here as it is defined as 0x0 in ARM ARM.

purgatory/arch/arm64/cache.c line 154

Quoted 6 lines

purgatory/arch/arm64/cache.c new file +5 -0

+static void init_page_table(void)
+{
+	inval_cache_range((uint64_t)page_table,
+				(uint64_t)page_table + PAGE_TABLE_SIZE);
+	memset(page_table, 0, PAGE_TABLE_SIZE);

why invalidate first?

Quoted 12 lines

+ */

purgatory/arch/arm64/cache.c new file +10 -0

+static void create_identity_mapping(uint64_t start, uint64_t end,
+					uint64_t flags)
+{
+	uint32_t sec_shift, pgdir_shift, sec_mask;
+	uint64_t desc, s1, e1, s2, e2;
+	uint64_t *table2;
+
+	s1 = start;
+	e1 = end;
+

purgatory/arch/arm64/cache.c line 181

Quoted 10 lines

purgatory/arch/arm64/cache.c new file +10 -0

+	sec_shift = get_section_shift();
+	if (pgtable_level == 1) {
+		s1 >>= sec_shift;
+		e1 >>= sec_shift;
+		do {
+			desc = s1 << sec_shift;
+			desc |= flags;
+			page_table[s1] = desc;
+			s1++;
+		} while (s1 <= e1);

To be precise, this loop creates an unnecessary entry if 'end' is exclusive. Pls think about the case that end is on sector boundary. Maybe,

    e1 = (e1 - 1) >> sec_shift

purgatory/arch/arm64/cache.c line 192

Quoted 12 lines

purgatory/arch/arm64/cache.c new file +11 -0

+	} else {
+		pgdir_shift = get_pgdir_shift();
+		sec_mask = get_section_mask();
+		s1 >>= pgdir_shift;
+		e1 >>= pgdir_shift;
+		do {
+			/*
+			 * If there is no table entry then write a new
+			 * entry else, use old entry
+			 */
+			if (!page_table[s1]) {

s1 can be larger than 0, 1 or 2 if ram is located at much higher address than the first (three) sector(s).

Quoted 21 lines

purgatory/arch/arm64/cache.c new file +20 -0

+static void enable_mmu_dcache(void)
+{
+	uint64_t tcr_flags = TCR_FLAGS | TCR_T0SZ(va_bits);
+
+	switch(page_shift) {
+	case 16:
+		tcr_flags |= TCR_TG0_64K;
+		break;
+	case 12:
+		tcr_flags |= TCR_TG0_4K;
+		break;
+	default:
+		printf("page shift not supported\n");
+		return;
+	}
+	/*
+	 * Since the page tables have been populated with non-cacheable
+	 * accesses (MMU disabled), invalidate the idmap page
+	 * tables again to remove any speculatively loaded cache lines.
+	 */

purgatory/arch/arm64/cache.c line 244

Quoted 5 lines

purgatory/arch/arm64/cache.c new file +5 -0

+	inval_cache_range((uint64_t)page_table,
+				(uint64_t)page_table + PAGE_TABLE_SIZE);
+
+	switch(get_current_el()) {
+	case 3:

Linux kernel should be started only in EL2 or non-secure EL1. why should we take care of el3?

purgatory/arch/arm64/cache.c line 320

Quoted 7 lines

purgatory/arch/arm64/cache.c new file +6 -0

+void disable_dcache(uint64_t ram_start, uint64_t ram_end)
+{
+	switch(get_current_el()) {
+	case 3:
+		reset_sctlr_el3();
+		break;

ditto

purgatory/arch/arm64/cache.h line 36

Quoted 13 lines

purgatory/arch/arm64/cache.h new file +12 -0

+#define ID_AA64MMFR0_PARANGE_40		0x2
+#define ID_AA64MMFR0_PARANGE_36		0x1
+#define ID_AA64MMFR0_PARANGE_32		0x0
+
+#define TCR_TG0_64K 		(1UL << 14)
+#define TCR_TG0_4K 		(0UL << 14)
+#define TCR_SHARED_NONE		(0UL << 12)
+#define TCR_ORGN_WBWA		(1UL << 10)
+#define TCR_IRGN_WBWA		(1UL << 8)
+#define TCR_IPS_EL1_SHIFT	32
+#define TCR_IPS_EL2_SHIFT	16
+#define TCR_IPS_EL3_SHIFT	16

TCR_PS_EL[23]_SHIFT?

Hi Akashi,

Thanks for your review.

Quoted 5 lines · AKASHI Takahiro

purgatory/arch/arm64/cache.c line 103

Quoted 2 lines

purgatory/arch/arm64/cache.c new file +2 -0

+	default:
+		return 32;

AA64MMFR0_PRANGE_32, instead of 'default', should explicitly be used here as it is defined as 0x0 in ARM ARM.

OK.

Quoted 8 lines

purgatory/arch/arm64/cache.c line 154

Quoted 6 lines

purgatory/arch/arm64/cache.c new file +5 -0

+static void init_page_table(void)
+{
+	inval_cache_range((uint64_t)page_table,
+				(uint64_t)page_table + PAGE_TABLE_SIZE);
+	memset(page_table, 0, PAGE_TABLE_SIZE);

why invalidate first?

Humm..may be you are right. It was copied from arch/arm64/kernel/head.S.
http://lxr.free-electrons.com/source/arch/arm64/kernel/head.S#L322

Quoted 26 lines

Quoted 12 lines

+ */

purgatory/arch/arm64/cache.c new file +10 -0

+static void create_identity_mapping(uint64_t start, uint64_t end,
+					uint64_t flags)
+{
+	uint32_t sec_shift, pgdir_shift, sec_mask;
+	uint64_t desc, s1, e1, s2, e2;
+	uint64_t *table2;
+
+	s1 = start;
+	e1 = end;
+

purgatory/arch/arm64/cache.c line 181

Quoted 10 lines

purgatory/arch/arm64/cache.c new file +10 -0

+	sec_shift = get_section_shift();
+	if (pgtable_level == 1) {
+		s1 >>= sec_shift;
+		e1 >>= sec_shift;
+		do {
+			desc = s1 << sec_shift;
+			desc |= flags;
+			page_table[s1] = desc;
+			s1++;
+		} while (s1 <= e1);

To be precise, this loop creates an unnecessary entry if 'end' is exclusive. Pls think about the case that end is on sector boundary. Maybe,

Quoted 1 line

     e1 = (e1 - 1) >> sec_shift

Correct.

Quoted 15 lines

purgatory/arch/arm64/cache.c line 192

Quoted 12 lines

purgatory/arch/arm64/cache.c new file +11 -0

+	} else {
+		pgdir_shift = get_pgdir_shift();
+		sec_mask = get_section_mask();
+		s1 >>= pgdir_shift;
+		e1 >>= pgdir_shift;
+		do {
+			/*
+			 * If there is no table entry then write a new
+			 * entry else, use old entry
+			 */
+			if (!page_table[s1]) {

s1 can be larger than 0, 1 or 2 if ram is located at much higher address than the first (three) sector(s).

Yes, that can most likely be, but code will take care.
From page_table[0] to page_table[MAX_PAGE_SIZE / sizeof(uint64_t)] will have entries
for 1st table.

we can have at max three tables.

table1 points to &page_table[0]
table2 points to &page_table[ MAX_PAGE_SIZE / sizeof(uint64_t)] table3 points to &page_table[ 2 * MAX_PAGE_SIZE / sizeof(uint64_t)]

each table can contain number of entries = MAX_PAGE_SIZE / sizeof(uint64_t), so if s1 > 3, it should work fine.

Quoted 21 lines

Quoted 21 lines

purgatory/arch/arm64/cache.c new file +20 -0

+static void enable_mmu_dcache(void)
+{
+	uint64_t tcr_flags = TCR_FLAGS | TCR_T0SZ(va_bits);
+
+	switch(page_shift) {
+	case 16:
+		tcr_flags |= TCR_TG0_64K;
+		break;
+	case 12:
+		tcr_flags |= TCR_TG0_4K;
+		break;
+	default:
+		printf("page shift not supported\n");
+		return;
+	}
+	/*
+	 * Since the page tables have been populated with non-cacheable
+	 * accesses (MMU disabled), invalidate the idmap page
+	 * tables again to remove any speculatively loaded cache lines.
+	 */

Quoted 8 lines

purgatory/arch/arm64/cache.c line 244

Quoted 5 lines

purgatory/arch/arm64/cache.c new file +5 -0

+	inval_cache_range((uint64_t)page_table,
+				(uint64_t)page_table + PAGE_TABLE_SIZE);
+
+	switch(get_current_el()) {
+	case 3:

Linux kernel should be started only in EL2 or non-secure EL1. why should we take care of el3?

I was not sure about it, so kept it. OK.. Will remove in next version.

Quoted 9 lines

purgatory/arch/arm64/cache.c line 320

Quoted 7 lines

purgatory/arch/arm64/cache.c new file +6 -0

+void disable_dcache(uint64_t ram_start, uint64_t ram_end)
+{
+	switch(get_current_el()) {
+	case 3:
+		reset_sctlr_el3();
+		break;

ditto

OK.

Quoted 15 lines

purgatory/arch/arm64/cache.h line 36

Quoted 13 lines

purgatory/arch/arm64/cache.h new file +12 -0

+#define ID_AA64MMFR0_PARANGE_40		0x2
+#define ID_AA64MMFR0_PARANGE_36		0x1
+#define ID_AA64MMFR0_PARANGE_32		0x0
+
+#define TCR_TG0_64K 		(1UL << 14)
+#define TCR_TG0_4K 		(0UL << 14)
+#define TCR_SHARED_NONE		(0UL << 12)
+#define TCR_ORGN_WBWA		(1UL << 10)
+#define TCR_IRGN_WBWA		(1UL << 8)
+#define TCR_IPS_EL1_SHIFT	32
+#define TCR_IPS_EL2_SHIFT	16
+#define TCR_IPS_EL3_SHIFT	16

TCR_PS_EL[23]_SHIFT?

OK :-) , Did not noticed it earlier.

~Pratyush

Quoted 7 lines

purgatory/arch/arm64/cache.c line 154

Quoted 5 lines

purgatory/arch/arm64/cache.c new file +5 -0

+static void init_page_table(void)
+{
+	inval_cache_range((uint64_t)page_table,
+				(uint64_t)page_table + PAGE_TABLE_SIZE);
+	memset(page_table, 0, PAGE_TABLE_SIZE);

why invalidate first?

Humm..may be you are right. It was copied from arch/arm64/kernel/head.S.
http://lxr.free-electrons.com/source/arch/arm64/kernel/head.S#L322

When "enable-dcache" is passed to the kexec() command line, kexec-tools passes this information to purgatory, which in turn enables cache during sha-256 verification.

RAM boundary which includes all the sections is needed for creating identity page mapping and to enable d-cache for those areas. Therefore these informations are passed to purgatory as well.

Signed-off-by Pratyush Anand <[email protected]>

---
  kexec/arch/arm64/include/arch/options.h |  6 +++++-
  kexec/arch/arm64/include/types.h        | 16 ++++++++++++++++
  kexec/arch/arm64/kexec-arm64.c          | 24 +++++++++++++++++++++++-
  purgatory/arch/arm64/entry.S            | 15 +++++++++++++++
  purgatory/arch/arm64/purgatory-arm64.c  | 10 +++++++++-
  5 files changed, 68 insertions(+), 3 deletions(-)

create mode 100644 kexec/arch/arm64/include/types.h

kexec/arch/arm64/include/arch/options.h +2 -1

index fbe17de595a9..3d84bb12ee37 100644
@@ -8,7 +8,8 @@
  #define OPT_PORT		((OPT_MAX)+4)
  #define OPT_REUSE_CMDLINE	((OPT_MAX)+5)
  #define OPT_PORT_LSR		((OPT_MAX)+6)
-#define OPT_ARCH_MAX		((OPT_MAX)+7)
+#define OPT_ENABLE_DCACHE	((OPT_MAX)+7)
+#define OPT_ARCH_MAX		((OPT_MAX)+8)
 
  #define KEXEC_ARCH_OPTIONS \
  	KEXEC_OPTIONS \

kexec/arch/arm64/include/arch/options.h +1 -0

  "     --ramdisk=FILE        Use FILE as the kernel initial ramdisk.\n"
  "     --reuse-cmdline       Use command line arg of primary kernel.\n";
 

@@ -44,6 +47,7 @@ struct arm64_opts {
  	uint64_t port;
  	uint64_t port_lsr;
  	uint32_t port_lsr_val;
+	uint32_t enable_dcache;
  };
 
  extern struct arm64_opts arm64_opts;

kexec/arch/arm64/include/types.h new file +16 -0

new file mode 100644
index 000000000000..08f833a6d585
@@ -0,0 +1,16 @@
+#ifndef _TYPES_H_
+#define _TYPES_H_
+
+#define min(x,y) ({ \
+	typeof(x) _x = (x);	\
+	typeof(y) _y = (y);	\
+	(void) (&_x == &_y);	\
+	_x < _y ? _x : _y; })
+
+#define max(x,y) ({ \
+	typeof(x) _x = (x);	\
+	typeof(y) _y = (y);	\
+	(void) (&_x == &_y);	\
+	_x > _y ? _x : _y; })
+
+#endif /* _TYPES_H_ */

kexec/arch/arm64/kexec-arm64.c +23 -1

index be9170af06e8..9b78b481f4a0 100644
@@ -29,6 +29,7 @@
  #include "fs2dt.h"
  #include "kexec-syscall.h"
  #include "arch/options.h"
+#include "types.h"
 
  /* Global varables the core kexec routines expect. */
 

@@ -103,6 +104,9 @@ int arch_process_options(int argc, char **argv)
  			arm64_opts.port_lsr_val = strtoul(strtok(NULL, ","),
  							NULL, 0);
  			break;
+		case OPT_ENABLE_DCACHE:
+			arm64_opts.enable_dcache = 1;
+			break;
  		case OPT_PAGE_OFFSET:
  			arm64_opts.page_offset = strtoull(optarg, NULL, 0);
  			break;

@@ -591,12 +595,15 @@ static uint64_t read_sink(const char *command_line)
  int arm64_load_other_segments(struct kexec_info *info,
  	uint64_t kernel_entry, char *option)
  {
-	int result;
+	int result, i;
  	uint64_t dtb_base;
+	unsigned long arm64_ram_start = -1;
+	unsigned long arm64_ram_end = 0;
  	unsigned long hole_min, hole_max;
  	uint64_t purgatory_sink;
  	uint64_t purgatory_sink_lsr;
  	uint32_t purgatory_sink_lsr_val;
+	uint32_t purgatory_enable_dcache;
  	struct mem_ehdr ehdr;
  	char *initrd_buf = NULL;
  	struct dtb dtb_1 = {.name = "dtb_1"};

@@ -621,6 +628,7 @@ int arm64_load_other_segments(struct kexec_info *info,
 
  	purgatory_sink_lsr = arm64_opts.port_lsr;
  	purgatory_sink_lsr_val = arm64_opts.port_lsr_val;
+	purgatory_enable_dcache = arm64_opts.enable_dcache;
 
  	if (arm64_opts.dtb) {
  		dtb_2.buf = slurp_file(arm64_opts.dtb, &dtb_2.size);

@@ -724,11 +732,25 @@ int arm64_load_other_segments(struct kexec_info *info,
  	elf_rel_set_symbol(&info->rhdr, "arm64_sink_lsr_val",
  		&purgatory_sink_lsr_val, sizeof(purgatory_sink_lsr_val));
 
+	elf_rel_set_symbol(&info->rhdr, "arm64_enable_dcache",
+		&purgatory_enable_dcache, sizeof(purgatory_enable_dcache));
+
  	elf_rel_set_symbol(&info->rhdr, "arm64_kernel_entry", &kernel_entry,
  		sizeof(kernel_entry));
 
  	elf_rel_set_symbol(&info->rhdr, "arm64_dtb_addr", &dtb_base,
  		sizeof(dtb_base));
+	for (i = 0; i < info->nr_segments; i++) {
+		arm64_ram_start = min(arm64_ram_start,
+				(unsigned long)info->segment[i].mem);
+		arm64_ram_end = max(arm64_ram_end,
+				((unsigned long)info->segment[i].mem +
+				 info->segment[i].memsz));
+	}
+	elf_rel_set_symbol(&info->rhdr, "arm64_ram_start",
+			&arm64_ram_start, sizeof(arm64_ram_start));
+	elf_rel_set_symbol(&info->rhdr, "arm64_ram_end",
+			&arm64_ram_end, sizeof(arm64_ram_end));
 
  	return 0;
  }

purgatory/arch/arm64/entry.S +15 -0

index be184e9a7469..d5563459d078 100644
@@ -63,7 +63,22 @@ arm64_kexec_lite:
  	.quad	0
  size arm64_kexec_lite
 
+.globl arm64_ram_start
+arm64_ram_start:
+	.quad	0
+size arm64_ram_start
+
+.globl arm64_ram_end
+arm64_ram_end:
+	.quad	0
+size arm64_ram_end
+
  .globl arm64_sink_lsr_val
  arm64_sink_lsr_val:
  	.long	0
  size arm64_sink_lsr_val
+
+.globl arm64_enable_dcache
+arm64_enable_dcache:
+	.long	0
+size arm64_enable_dcache

purgatory/arch/arm64/purgatory-arm64.c +6 -0

index bca802e0504d..70c01aee46e0 100644
@@ -4,14 +4,18 @@
 
  #include <stdint.h>
  #include <purgatory.h>
+#include "cache.h"
 
  /* Symbols set by kexec. */
 
  extern uint32_t *arm64_sink;
  extern uint32_t *arm64_sink_lsr;
  extern uint32_t arm64_sink_lsr_val;
+extern uint32_t arm64_enable_dcache;
  extern void (*arm64_kernel_entry)(uint64_t, uint64_t, uint64_t, uint64_t);
  extern uint64_t arm64_dtb_addr;
+extern uint64_t arm64_ram_start;
+extern uint64_t arm64_ram_end;
 
  static void wait_for_xmit_complete(void)
  {

@@ -44,6 +48,8 @@ void putchar(int ch)
 
  void post_verification_setup_arch(void)
  {
+	if (arm64_enable_dcache)
+		disable_dcache(arm64_ram_start, arm64_ram_end);
  	arm64_kernel_entry(arm64_dtb_addr, 0, 0, 0);
  }
 

Quoted 30 lines · Pratyush Anand

When "enable-dcache" is passed to the kexec() command line, kexec-tools passes this information to purgatory, which in turn enables cache during sha-256 verification.

RAM boundary which includes all the sections is needed for creating identity page mapping and to enable d-cache for those areas. Therefore these informations are passed to purgatory as well.

Signed-off-by Pratyush Anand <[email protected]>

---
 kexec/arch/arm64/include/arch/options.h |  6 +++++-
 kexec/arch/arm64/include/types.h        | 16 ++++++++++++++++
 kexec/arch/arm64/kexec-arm64.c          | 24 +++++++++++++++++++++++-
 purgatory/arch/arm64/entry.S            | 15 +++++++++++++++
 purgatory/arch/arm64/purgatory-arm64.c  | 10 +++++++++-
 5 files changed, 68 insertions(+), 3 deletions(-)
 create mode 100644 kexec/arch/arm64/include/types.h

kexec/arch/arm64/include/arch/options.h +2 -1

index fbe17de595a9..3d84bb12ee37 100644
@@ -8,7 +8,8 @@
 #define OPT_PORT		((OPT_MAX)+4)
 #define OPT_REUSE_CMDLINE	((OPT_MAX)+5)
 #define OPT_PORT_LSR		((OPT_MAX)+6)
-#define OPT_ARCH_MAX		((OPT_MAX)+7)
+#define OPT_ENABLE_DCACHE	((OPT_MAX)+7)
+#define OPT_ARCH_MAX		((OPT_MAX)+8)
 

kexec/arch/arm64/include/arch/options.h line 24

Quoted 7 lines

kexec/arch/arm64/include/arch/options.h +1 -0

 #define KEXEC_ARCH_OPTIONS \
 	KEXEC_OPTIONS \

@@ -20,6 +21,7 @@
 	{ "port",         1, NULL, OPT_PORT }, \
 	{ "port-lsr",     1, NULL, OPT_PORT_LSR }, \
 	{ "ramdisk",      1, NULL, OPT_INITRD }, \
+	{ "enable-dcache", 0, NULL, OPT_ENABLE_DCACHE }, \

in alphabetical order, please.

kexec/arch/arm64/include/arch/options.h static const char arm64_opts_usage[] __attribute__ ((unused)) = · line 38

Quoted 9 lines

kexec/arch/arm64/include/arch/options.h +1 -0

 	{ "reuse-cmdline", 0, NULL, OPT_REUSE_CMDLINE }, \
 
 #define KEXEC_ARCH_OPT_STR KEXEC_OPT_STR /* Only accept long arch options. */

@@ -33,6 +35,7 @@ static const char arm64_opts_usage[] __attribute__ ((unused)) =
 "     --initrd=FILE         Use FILE as the kernel initial ramdisk.\n"
 "     --port=ADDRESS        Purgatory output to port ADDRESS.\n"
 "     --port-lsr=ADDR,VAL   Purgatory output port line status address and TX Empty Bit Field.\n"
+"     --enable-dcache       Enable D-Cache in Purgatory for faster SHA verification.\n"

ditto :)