Initial import

8 files changed, 598 insertions, 0 deletions

diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile
new file mode 100644
index 000000000..2c835e356
--- /dev/null
+++ b/arch/x86/purgatory/Makefile
@@ -0,0 +1,30 @@
+purgatory-y := purgatory.o stack.o setup-x86_$(BITS).o sha256.o entry64.o string.o
+
+targets += $(purgatory-y)
+PURGATORY_OBJS = $(addprefix $(obj)/,$(purgatory-y))
+
+LDFLAGS_purgatory.ro := -e purgatory_start -r --no-undefined -nostdlib -z nodefaultlib
+targets += purgatory.ro
+
+# Default KBUILD_CFLAGS can have -pg option set when FTRACE is enabled. That
+# in turn leaves some undefined symbols like __fentry__ in purgatory and not
+# sure how to relocate those. Like kexec-tools, use custom flags.
+
+KBUILD_CFLAGS := -fno-strict-aliasing -Wall -Wstrict-prototypes -fno-zero-initialized-in-bss -fno-builtin -ffreestanding -c -MD -Os -mcmodel=large
+KBUILD_CFLAGS += -m$(BITS)
+
+$(obj)/purgatory.ro: $(PURGATORY_OBJS) FORCE
+		$(call if_changed,ld)
+
+targets += kexec-purgatory.c
+
+CMD_BIN2C = $(objtree)/scripts/basic/bin2c
+quiet_cmd_bin2c = BIN2C   $@
+      cmd_bin2c = $(CMD_BIN2C) kexec_purgatory < $< > $@
+
+$(obj)/kexec-purgatory.c: $(obj)/purgatory.ro FORCE
+	$(call if_changed,bin2c)
+	@:
+
+
+obj-$(CONFIG_KEXEC_FILE)	+= kexec-purgatory.o
diff --git a/arch/x86/purgatory/entry64.S b/arch/x86/purgatory/entry64.S
new file mode 100644
index 000000000..d1a4291d3
--- /dev/null
+++ b/arch/x86/purgatory/entry64.S
@@ -0,0 +1,101 @@
+/*
+ * Copyright (C) 2003,2004  Eric Biederman (ebiederm@xmission.com)
+ * Copyright (C) 2014  Red Hat Inc.
+
+ * Author(s): Vivek Goyal <vgoyal@redhat.com>
+ *
+ * This code has been taken from kexec-tools.
+ *
+ * This source code is licensed under the GNU General Public License,
+ * Version 2.  See the file COPYING for more details.
+ */
+
+	.text
+	.balign 16
+	.code64
+	.globl entry64, entry64_regs
+
+
+entry64:
+	/* Setup a gdt that should be preserved */
+	lgdt gdt(%rip)
+
+	/* load the data segments */
+	movl    $0x18, %eax     /* data segment */
+	movl    %eax, %ds
+	movl    %eax, %es
+	movl    %eax, %ss
+	movl    %eax, %fs
+	movl    %eax, %gs
+
+	/* Setup new stack */
+	leaq    stack_init(%rip), %rsp
+	pushq   $0x10 /* CS */
+	leaq    new_cs_exit(%rip), %rax
+	pushq   %rax
+	lretq
+new_cs_exit:
+
+	/* Load the registers */
+	movq	rax(%rip), %rax
+	movq	rbx(%rip), %rbx
+	movq	rcx(%rip), %rcx
+	movq	rdx(%rip), %rdx
+	movq	rsi(%rip), %rsi
+	movq	rdi(%rip), %rdi
+	movq    rsp(%rip), %rsp
+	movq	rbp(%rip), %rbp
+	movq	r8(%rip), %r8
+	movq	r9(%rip), %r9
+	movq	r10(%rip), %r10
+	movq	r11(%rip), %r11
+	movq	r12(%rip), %r12
+	movq	r13(%rip), %r13
+	movq	r14(%rip), %r14
+	movq	r15(%rip), %r15
+
+	/* Jump to the new code... */
+	jmpq	*rip(%rip)
+
+	.section ".rodata"
+	.balign 4
+entry64_regs:
+rax:	.quad 0x0
+rcx:	.quad 0x0
+rdx:	.quad 0x0
+rbx:	.quad 0x0
+rsp:	.quad 0x0
+rbp:	.quad 0x0
+rsi:	.quad 0x0
+rdi:	.quad 0x0
+r8:	.quad 0x0
+r9:	.quad 0x0
+r10:	.quad 0x0
+r11:	.quad 0x0
+r12:	.quad 0x0
+r13:	.quad 0x0
+r14:	.quad 0x0
+r15:	.quad 0x0
+rip:	.quad 0x0
+	.size entry64_regs, . - entry64_regs
+
+	/* GDT */
+	.section ".rodata"
+	.balign 16
+gdt:
+	/* 0x00 unusable segment
+	 * 0x08 unused
+	 * so use them as gdt ptr
+	 */
+	.word gdt_end - gdt - 1
+	.quad gdt
+	.word 0, 0, 0
+
+	/* 0x10 4GB flat code segment */
+	.word 0xFFFF, 0x0000, 0x9A00, 0x00AF
+
+	/* 0x18 4GB flat data segment */
+	.word 0xFFFF, 0x0000, 0x9200, 0x00CF
+gdt_end:
+stack:	.quad   0, 0
+stack_init:
diff --git a/arch/x86/purgatory/purgatory.c b/arch/x86/purgatory/purgatory.c
new file mode 100644
index 000000000..25e068ba3
--- /dev/null
+++ b/arch/x86/purgatory/purgatory.c
@@ -0,0 +1,72 @@
+/*
+ * purgatory: Runs between two kernels
+ *
+ * Copyright (C) 2014 Red Hat Inc.
+ *
+ * Author:
+ *       Vivek Goyal <vgoyal@redhat.com>
+ *
+ * This source code is licensed under the GNU General Public License,
+ * Version 2.  See the file COPYING for more details.
+ */
+
+#include "sha256.h"
+#include "../boot/string.h"
+
+struct sha_region {
+	unsigned long start;
+	unsigned long len;
+};
+
+unsigned long backup_dest = 0;
+unsigned long backup_src = 0;
+unsigned long backup_sz = 0;
+
+u8 sha256_digest[SHA256_DIGEST_SIZE] = { 0 };
+
+struct sha_region sha_regions[16] = {};
+
+/*
+ * On x86, second kernel requries first 640K of memory to boot. Copy
+ * first 640K to a backup region in reserved memory range so that second
+ * kernel can use first 640K.
+ */
+static int copy_backup_region(void)
+{
+	if (backup_dest)
+		memcpy((void *)backup_dest, (void *)backup_src, backup_sz);
+
+	return 0;
+}
+
+int verify_sha256_digest(void)
+{
+	struct sha_region *ptr, *end;
+	u8 digest[SHA256_DIGEST_SIZE];
+	struct sha256_state sctx;
+
+	sha256_init(&sctx);
+	end = &sha_regions[sizeof(sha_regions)/sizeof(sha_regions[0])];
+	for (ptr = sha_regions; ptr < end; ptr++)
+		sha256_update(&sctx, (uint8_t *)(ptr->start), ptr->len);
+
+	sha256_final(&sctx, digest);
+
+	if (memcmp(digest, sha256_digest, sizeof(digest)))
+		return 1;
+
+	return 0;
+}
+
+void purgatory(void)
+{
+	int ret;
+
+	ret = verify_sha256_digest();
+	if (ret) {
+		/* loop forever */
+		for (;;)
+			;
+	}
+	copy_backup_region();
+}
diff --git a/arch/x86/purgatory/setup-x86_64.S b/arch/x86/purgatory/setup-x86_64.S
new file mode 100644
index 000000000..fe3c91ba1
--- /dev/null
+++ b/arch/x86/purgatory/setup-x86_64.S
@@ -0,0 +1,58 @@
+/*
+ * purgatory:  setup code
+ *
+ * Copyright (C) 2003,2004  Eric Biederman (ebiederm@xmission.com)
+ * Copyright (C) 2014 Red Hat Inc.
+ *
+ * This code has been taken from kexec-tools.
+ *
+ * This source code is licensed under the GNU General Public License,
+ * Version 2.  See the file COPYING for more details.
+ */
+
+	.text
+	.globl purgatory_start
+	.balign 16
+purgatory_start:
+	.code64
+
+	/* Load a gdt so I know what the segment registers are */
+	lgdt	gdt(%rip)
+
+	/* load the data segments */
+	movl	$0x18, %eax	/* data segment */
+	movl	%eax, %ds
+	movl	%eax, %es
+	movl	%eax, %ss
+	movl	%eax, %fs
+	movl	%eax, %gs
+
+	/* Setup a stack */
+	leaq	lstack_end(%rip), %rsp
+
+	/* Call the C code */
+	call purgatory
+	jmp	entry64
+
+	.section ".rodata"
+	.balign 16
+gdt:	/* 0x00 unusable segment
+	 * 0x08 unused
+	 * so use them as the gdt ptr
+	 */
+	.word	gdt_end - gdt - 1
+	.quad	gdt
+	.word	0, 0, 0
+
+	/* 0x10 4GB flat code segment */
+	.word	0xFFFF, 0x0000, 0x9A00, 0x00AF
+
+	/* 0x18 4GB flat data segment */
+	.word	0xFFFF, 0x0000, 0x9200, 0x00CF
+gdt_end:
+
+	.bss
+	.balign 4096
+lstack:
+	.skip 4096
+lstack_end:
diff --git a/arch/x86/purgatory/sha256.c b/arch/x86/purgatory/sha256.c
new file mode 100644
index 000000000..548ca675a
--- /dev/null
+++ b/arch/x86/purgatory/sha256.c
@@ -0,0 +1,283 @@
+/*
+ * SHA-256, as specified in
+ * http://csrc.nist.gov/groups/STM/cavp/documents/shs/sha256-384-512.pdf
+ *
+ * SHA-256 code by Jean-Luc Cooke <jlcooke@certainkey.com>.
+ *
+ * Copyright (c) Jean-Luc Cooke <jlcooke@certainkey.com>
+ * Copyright (c) Andrew McDonald <andrew@mcdonald.org.uk>
+ * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
+ * Copyright (c) 2014 Red Hat Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ */
+
+#include <linux/bitops.h>
+#include <asm/byteorder.h>
+#include "sha256.h"
+#include "../boot/string.h"
+
+static inline u32 Ch(u32 x, u32 y, u32 z)
+{
+	return z ^ (x & (y ^ z));
+}
+
+static inline u32 Maj(u32 x, u32 y, u32 z)
+{
+	return (x & y) | (z & (x | y));
+}
+
+#define e0(x)       (ror32(x, 2) ^ ror32(x, 13) ^ ror32(x, 22))
+#define e1(x)       (ror32(x, 6) ^ ror32(x, 11) ^ ror32(x, 25))
+#define s0(x)       (ror32(x, 7) ^ ror32(x, 18) ^ (x >> 3))
+#define s1(x)       (ror32(x, 17) ^ ror32(x, 19) ^ (x >> 10))
+
+static inline void LOAD_OP(int I, u32 *W, const u8 *input)
+{
+	W[I] = __be32_to_cpu(((__be32 *)(input))[I]);
+}
+
+static inline void BLEND_OP(int I, u32 *W)
+{
+	W[I] = s1(W[I-2]) + W[I-7] + s0(W[I-15]) + W[I-16];
+}
+
+static void sha256_transform(u32 *state, const u8 *input)
+{
+	u32 a, b, c, d, e, f, g, h, t1, t2;
+	u32 W[64];
+	int i;
+
+	/* load the input */
+	for (i = 0; i < 16; i++)
+		LOAD_OP(i, W, input);
+
+	/* now blend */
+	for (i = 16; i < 64; i++)
+		BLEND_OP(i, W);
+
+	/* load the state into our registers */
+	a = state[0];  b = state[1];  c = state[2];  d = state[3];
+	e = state[4];  f = state[5];  g = state[6];  h = state[7];
+
+	/* now iterate */
+	t1 = h + e1(e) + Ch(e, f, g) + 0x428a2f98 + W[0];
+	t2 = e0(a) + Maj(a, b, c);    d += t1;    h = t1 + t2;
+	t1 = g + e1(d) + Ch(d, e, f) + 0x71374491 + W[1];
+	t2 = e0(h) + Maj(h, a, b);    c += t1;    g = t1 + t2;
+	t1 = f + e1(c) + Ch(c, d, e) + 0xb5c0fbcf + W[2];
+	t2 = e0(g) + Maj(g, h, a);    b += t1;    f = t1 + t2;
+	t1 = e + e1(b) + Ch(b, c, d) + 0xe9b5dba5 + W[3];
+	t2 = e0(f) + Maj(f, g, h);    a += t1;    e = t1 + t2;
+	t1 = d + e1(a) + Ch(a, b, c) + 0x3956c25b + W[4];
+	t2 = e0(e) + Maj(e, f, g);    h += t1;    d = t1 + t2;
+	t1 = c + e1(h) + Ch(h, a, b) + 0x59f111f1 + W[5];
+	t2 = e0(d) + Maj(d, e, f);    g += t1;    c = t1 + t2;
+	t1 = b + e1(g) + Ch(g, h, a) + 0x923f82a4 + W[6];
+	t2 = e0(c) + Maj(c, d, e);    f += t1;    b = t1 + t2;
+	t1 = a + e1(f) + Ch(f, g, h) + 0xab1c5ed5 + W[7];
+	t2 = e0(b) + Maj(b, c, d);    e += t1;    a = t1 + t2;
+
+	t1 = h + e1(e) + Ch(e, f, g) + 0xd807aa98 + W[8];
+	t2 = e0(a) + Maj(a, b, c);    d += t1;    h = t1 + t2;
+	t1 = g + e1(d) + Ch(d, e, f) + 0x12835b01 + W[9];
+	t2 = e0(h) + Maj(h, a, b);    c += t1;    g = t1 + t2;
+	t1 = f + e1(c) + Ch(c, d, e) + 0x243185be + W[10];
+	t2 = e0(g) + Maj(g, h, a);    b += t1;    f = t1 + t2;
+	t1 = e + e1(b) + Ch(b, c, d) + 0x550c7dc3 + W[11];
+	t2 = e0(f) + Maj(f, g, h);    a += t1;    e = t1 + t2;
+	t1 = d + e1(a) + Ch(a, b, c) + 0x72be5d74 + W[12];
+	t2 = e0(e) + Maj(e, f, g);    h += t1;    d = t1 + t2;
+	t1 = c + e1(h) + Ch(h, a, b) + 0x80deb1fe + W[13];
+	t2 = e0(d) + Maj(d, e, f);    g += t1;    c = t1 + t2;
+	t1 = b + e1(g) + Ch(g, h, a) + 0x9bdc06a7 + W[14];
+	t2 = e0(c) + Maj(c, d, e);    f += t1;    b = t1 + t2;
+	t1 = a + e1(f) + Ch(f, g, h) + 0xc19bf174 + W[15];
+	t2 = e0(b) + Maj(b, c, d);    e += t1;    a = t1+t2;
+
+	t1 = h + e1(e) + Ch(e, f, g) + 0xe49b69c1 + W[16];
+	t2 = e0(a) + Maj(a, b, c);    d += t1;    h = t1+t2;
+	t1 = g + e1(d) + Ch(d, e, f) + 0xefbe4786 + W[17];
+	t2 = e0(h) + Maj(h, a, b);    c += t1;    g = t1+t2;
+	t1 = f + e1(c) + Ch(c, d, e) + 0x0fc19dc6 + W[18];
+	t2 = e0(g) + Maj(g, h, a);    b += t1;    f = t1+t2;
+	t1 = e + e1(b) + Ch(b, c, d) + 0x240ca1cc + W[19];
+	t2 = e0(f) + Maj(f, g, h);    a += t1;    e = t1+t2;
+	t1 = d + e1(a) + Ch(a, b, c) + 0x2de92c6f + W[20];
+	t2 = e0(e) + Maj(e, f, g);    h += t1;    d = t1+t2;
+	t1 = c + e1(h) + Ch(h, a, b) + 0x4a7484aa + W[21];
+	t2 = e0(d) + Maj(d, e, f);    g += t1;    c = t1+t2;
+	t1 = b + e1(g) + Ch(g, h, a) + 0x5cb0a9dc + W[22];
+	t2 = e0(c) + Maj(c, d, e);    f += t1;    b = t1+t2;
+	t1 = a + e1(f) + Ch(f, g, h) + 0x76f988da + W[23];
+	t2 = e0(b) + Maj(b, c, d);    e += t1;    a = t1+t2;
+
+	t1 = h + e1(e) + Ch(e, f, g) + 0x983e5152 + W[24];
+	t2 = e0(a) + Maj(a, b, c);    d += t1;    h = t1+t2;
+	t1 = g + e1(d) + Ch(d, e, f) + 0xa831c66d + W[25];
+	t2 = e0(h) + Maj(h, a, b);    c += t1;    g = t1+t2;
+	t1 = f + e1(c) + Ch(c, d, e) + 0xb00327c8 + W[26];
+	t2 = e0(g) + Maj(g, h, a);    b += t1;    f = t1+t2;
+	t1 = e + e1(b) + Ch(b, c, d) + 0xbf597fc7 + W[27];
+	t2 = e0(f) + Maj(f, g, h);    a += t1;    e = t1+t2;
+	t1 = d + e1(a) + Ch(a, b, c) + 0xc6e00bf3 + W[28];
+	t2 = e0(e) + Maj(e, f, g);    h += t1;    d = t1+t2;
+	t1 = c + e1(h) + Ch(h, a, b) + 0xd5a79147 + W[29];
+	t2 = e0(d) + Maj(d, e, f);    g += t1;    c = t1+t2;
+	t1 = b + e1(g) + Ch(g, h, a) + 0x06ca6351 + W[30];
+	t2 = e0(c) + Maj(c, d, e);    f += t1;    b = t1+t2;
+	t1 = a + e1(f) + Ch(f, g, h) + 0x14292967 + W[31];
+	t2 = e0(b) + Maj(b, c, d);    e += t1;    a = t1+t2;
+
+	t1 = h + e1(e) + Ch(e, f, g) + 0x27b70a85 + W[32];
+	t2 = e0(a) + Maj(a, b, c);    d += t1;    h = t1+t2;
+	t1 = g + e1(d) + Ch(d, e, f) + 0x2e1b2138 + W[33];
+	t2 = e0(h) + Maj(h, a, b);    c += t1;    g = t1+t2;
+	t1 = f + e1(c) + Ch(c, d, e) + 0x4d2c6dfc + W[34];
+	t2 = e0(g) + Maj(g, h, a);    b += t1;    f = t1+t2;
+	t1 = e + e1(b) + Ch(b, c, d) + 0x53380d13 + W[35];
+	t2 = e0(f) + Maj(f, g, h);    a += t1;    e = t1+t2;
+	t1 = d + e1(a) + Ch(a, b, c) + 0x650a7354 + W[36];
+	t2 = e0(e) + Maj(e, f, g);    h += t1;    d = t1+t2;
+	t1 = c + e1(h) + Ch(h, a, b) + 0x766a0abb + W[37];
+	t2 = e0(d) + Maj(d, e, f);    g += t1;    c = t1+t2;
+	t1 = b + e1(g) + Ch(g, h, a) + 0x81c2c92e + W[38];
+	t2 = e0(c) + Maj(c, d, e);    f += t1;    b = t1+t2;
+	t1 = a + e1(f) + Ch(f, g, h) + 0x92722c85 + W[39];
+	t2 = e0(b) + Maj(b, c, d);    e += t1;    a = t1+t2;
+
+	t1 = h + e1(e) + Ch(e, f, g) + 0xa2bfe8a1 + W[40];
+	t2 = e0(a) + Maj(a, b, c);    d += t1;    h = t1+t2;
+	t1 = g + e1(d) + Ch(d, e, f) + 0xa81a664b + W[41];
+	t2 = e0(h) + Maj(h, a, b);    c += t1;    g = t1+t2;
+	t1 = f + e1(c) + Ch(c, d, e) + 0xc24b8b70 + W[42];
+	t2 = e0(g) + Maj(g, h, a);    b += t1;    f = t1+t2;
+	t1 = e + e1(b) + Ch(b, c, d) + 0xc76c51a3 + W[43];
+	t2 = e0(f) + Maj(f, g, h);    a += t1;    e = t1+t2;
+	t1 = d + e1(a) + Ch(a, b, c) + 0xd192e819 + W[44];
+	t2 = e0(e) + Maj(e, f, g);    h += t1;    d = t1+t2;
+	t1 = c + e1(h) + Ch(h, a, b) + 0xd6990624 + W[45];
+	t2 = e0(d) + Maj(d, e, f);    g += t1;    c = t1+t2;
+	t1 = b + e1(g) + Ch(g, h, a) + 0xf40e3585 + W[46];
+	t2 = e0(c) + Maj(c, d, e);    f += t1;    b = t1+t2;
+	t1 = a + e1(f) + Ch(f, g, h) + 0x106aa070 + W[47];
+	t2 = e0(b) + Maj(b, c, d);    e += t1;    a = t1+t2;
+
+	t1 = h + e1(e) + Ch(e, f, g) + 0x19a4c116 + W[48];
+	t2 = e0(a) + Maj(a, b, c);    d += t1;    h = t1+t2;
+	t1 = g + e1(d) + Ch(d, e, f) + 0x1e376c08 + W[49];
+	t2 = e0(h) + Maj(h, a, b);    c += t1;    g = t1+t2;
+	t1 = f + e1(c) + Ch(c, d, e) + 0x2748774c + W[50];
+	t2 = e0(g) + Maj(g, h, a);    b += t1;    f = t1+t2;
+	t1 = e + e1(b) + Ch(b, c, d) + 0x34b0bcb5 + W[51];
+	t2 = e0(f) + Maj(f, g, h);    a += t1;    e = t1+t2;
+	t1 = d + e1(a) + Ch(a, b, c) + 0x391c0cb3 + W[52];
+	t2 = e0(e) + Maj(e, f, g);    h += t1;    d = t1+t2;
+	t1 = c + e1(h) + Ch(h, a, b) + 0x4ed8aa4a + W[53];
+	t2 = e0(d) + Maj(d, e, f);    g += t1;    c = t1+t2;
+	t1 = b + e1(g) + Ch(g, h, a) + 0x5b9cca4f + W[54];
+	t2 = e0(c) + Maj(c, d, e);    f += t1;    b = t1+t2;
+	t1 = a + e1(f) + Ch(f, g, h) + 0x682e6ff3 + W[55];
+	t2 = e0(b) + Maj(b, c, d);    e += t1;    a = t1+t2;
+
+	t1 = h + e1(e) + Ch(e, f, g) + 0x748f82ee + W[56];
+	t2 = e0(a) + Maj(a, b, c);    d += t1;    h = t1+t2;
+	t1 = g + e1(d) + Ch(d, e, f) + 0x78a5636f + W[57];
+	t2 = e0(h) + Maj(h, a, b);    c += t1;    g = t1+t2;
+	t1 = f + e1(c) + Ch(c, d, e) + 0x84c87814 + W[58];
+	t2 = e0(g) + Maj(g, h, a);    b += t1;    f = t1+t2;
+	t1 = e + e1(b) + Ch(b, c, d) + 0x8cc70208 + W[59];
+	t2 = e0(f) + Maj(f, g, h);    a += t1;    e = t1+t2;
+	t1 = d + e1(a) + Ch(a, b, c) + 0x90befffa + W[60];
+	t2 = e0(e) + Maj(e, f, g);    h += t1;    d = t1+t2;
+	t1 = c + e1(h) + Ch(h, a, b) + 0xa4506ceb + W[61];
+	t2 = e0(d) + Maj(d, e, f);    g += t1;    c = t1+t2;
+	t1 = b + e1(g) + Ch(g, h, a) + 0xbef9a3f7 + W[62];
+	t2 = e0(c) + Maj(c, d, e);    f += t1;    b = t1+t2;
+	t1 = a + e1(f) + Ch(f, g, h) + 0xc67178f2 + W[63];
+	t2 = e0(b) + Maj(b, c, d);    e += t1;    a = t1+t2;
+
+	state[0] += a; state[1] += b; state[2] += c; state[3] += d;
+	state[4] += e; state[5] += f; state[6] += g; state[7] += h;
+
+	/* clear any sensitive info... */
+	a = b = c = d = e = f = g = h = t1 = t2 = 0;
+	memset(W, 0, 64 * sizeof(u32));
+}
+
+int sha256_init(struct sha256_state *sctx)
+{
+	sctx->state[0] = SHA256_H0;
+	sctx->state[1] = SHA256_H1;
+	sctx->state[2] = SHA256_H2;
+	sctx->state[3] = SHA256_H3;
+	sctx->state[4] = SHA256_H4;
+	sctx->state[5] = SHA256_H5;
+	sctx->state[6] = SHA256_H6;
+	sctx->state[7] = SHA256_H7;
+	sctx->count = 0;
+
+	return 0;
+}
+
+int sha256_update(struct sha256_state *sctx, const u8 *data, unsigned int len)
+{
+	unsigned int partial, done;
+	const u8 *src;
+
+	partial = sctx->count & 0x3f;
+	sctx->count += len;
+	done = 0;
+	src = data;
+
+	if ((partial + len) > 63) {
+		if (partial) {
+			done = -partial;
+			memcpy(sctx->buf + partial, data, done + 64);
+			src = sctx->buf;
+		}
+
+		do {
+			sha256_transform(sctx->state, src);
+			done += 64;
+			src = data + done;
+		} while (done + 63 < len);
+
+		partial = 0;
+	}
+	memcpy(sctx->buf + partial, src, len - done);
+
+	return 0;
+}
+
+int sha256_final(struct sha256_state *sctx, u8 *out)
+{
+	__be32 *dst = (__be32 *)out;
+	__be64 bits;
+	unsigned int index, pad_len;
+	int i;
+	static const u8 padding[64] = { 0x80, };
+
+	/* Save number of bits */
+	bits = cpu_to_be64(sctx->count << 3);
+
+	/* Pad out to 56 mod 64. */
+	index = sctx->count & 0x3f;
+	pad_len = (index < 56) ? (56 - index) : ((64+56) - index);
+	sha256_update(sctx, padding, pad_len);
+
+	/* Append length (before padding) */
+	sha256_update(sctx, (const u8 *)&bits, sizeof(bits));
+
+	/* Store state in digest */
+	for (i = 0; i < 8; i++)
+		dst[i] = cpu_to_be32(sctx->state[i]);
+
+	/* Zeroize sensitive information. */
+	memset(sctx, 0, sizeof(*sctx));
+
+	return 0;
+}
diff --git a/arch/x86/purgatory/sha256.h b/arch/x86/purgatory/sha256.h
new file mode 100644
index 000000000..bd15a4127
--- /dev/null
+++ b/arch/x86/purgatory/sha256.h
@@ -0,0 +1,22 @@
+/*
+ *  Copyright (C) 2014 Red Hat Inc.
+ *
+ *  Author: Vivek Goyal <vgoyal@redhat.com>
+ *
+ * This source code is licensed under the GNU General Public License,
+ * Version 2.  See the file COPYING for more details.
+ */
+
+#ifndef SHA256_H
+#define SHA256_H
+
+
+#include <linux/types.h>
+#include <crypto/sha.h>
+
+extern int sha256_init(struct sha256_state *sctx);
+extern int sha256_update(struct sha256_state *sctx, const u8 *input,
+				unsigned int length);
+extern int sha256_final(struct sha256_state *sctx, u8 *hash);
+
+#endif /* SHA256_H */
diff --git a/arch/x86/purgatory/stack.S b/arch/x86/purgatory/stack.S
new file mode 100644
index 000000000..3cefba1fe
--- /dev/null
+++ b/arch/x86/purgatory/stack.S
@@ -0,0 +1,19 @@
+/*
+ * purgatory:  stack
+ *
+ * Copyright (C) 2014 Red Hat Inc.
+ *
+ * This source code is licensed under the GNU General Public License,
+ * Version 2.  See the file COPYING for more details.
+ */
+
+	/* A stack for the loaded kernel.
+	 * Seperate and in the data section so it can be prepopulated.
+	 */
+	.data
+	.balign 4096
+	.globl stack, stack_end
+
+stack:
+	.skip 4096
+stack_end:
diff --git a/arch/x86/purgatory/string.c b/arch/x86/purgatory/string.c
new file mode 100644
index 000000000..d886b1fa3
--- /dev/null
+++ b/arch/x86/purgatory/string.c
@@ -0,0 +1,13 @@
+/*
+ * Simple string functions.
+ *
+ * Copyright (C) 2014 Red Hat Inc.
+ *
+ * Author:
+ *       Vivek Goyal <vgoyal@redhat.com>
+ *
+ * This source code is licensed under the GNU General Public License,
+ * Version 2.  See the file COPYING for more details.
+ */
+
+#include "../boot/string.c"