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Revision 74ca317c26a3f8543203b61d262c0ab2e30c384e authored by Vivek Goyal on 29 August 2014, 22:18:46 UTC, committed by Linus Torvalds on 29 August 2014, 23:28:16 UTC 
kexec: create a new config option CONFIG_KEXEC_FILE for new syscall
 
Currently new system call kexec_file_load() and all the associated code
compiles if CONFIG_KEXEC=y.  But new syscall also compiles purgatory
code which currently uses gcc option -mcmodel=large.  This option seems
to be available only gcc 4.4 onwards.

Hiding new functionality behind a new config option will not break
existing users of old gcc.  Those who wish to enable new functionality
will require new gcc.  Having said that, I am trying to figure out how
can I move away from using -mcmodel=large but that can take a while.

I think there are other advantages of introducing this new config
option.  As this option will be enabled only on x86_64, other arches
don't have to compile generic kexec code which will never be used.  This
new code selects CRYPTO=y and CRYPTO_SHA256=y.  And all other arches had
to do this for CONFIG_KEXEC.  Now with introduction of new config
option, we can remove crypto dependency from other arches.

Now CONFIG_KEXEC_FILE is available only on x86_64.  So whereever I had
CONFIG_X86_64 defined, I got rid of that.

For CONFIG_KEXEC_FILE, instead of doing select CRYPTO=y, I changed it to
"depends on CRYPTO=y".  This should be safer as "select" is not
recursive.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Tested-by: Shaun Ruffell <sruffell@digium.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent b38af47
Raw File
dyntrans.c 
/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * KVM/MIPS: Binary Patching for privileged instructions, reduces traps.
 *
 * Copyright (C) 2012  MIPS Technologies, Inc.  All rights reserved.
 * Authors: Sanjay Lal <sanjayl@kymasys.com>
 */

#include <linux/errno.h>
#include <linux/err.h>
#include <linux/kvm_host.h>
#include <linux/module.h>
#include <linux/vmalloc.h>
#include <linux/fs.h>
#include <linux/bootmem.h>
#include <asm/cacheflush.h>

#include "commpage.h"

#define SYNCI_TEMPLATE  0x041f0000
#define SYNCI_BASE(x)   (((x) >> 21) & 0x1f)
#define SYNCI_OFFSET    ((x) & 0xffff)

#define LW_TEMPLATE     0x8c000000
#define CLEAR_TEMPLATE  0x00000020
#define SW_TEMPLATE     0xac000000

int kvm_mips_trans_cache_index(uint32_t inst, uint32_t *opc,
			       struct kvm_vcpu *vcpu)
{
	int result = 0;
	unsigned long kseg0_opc;
	uint32_t synci_inst = 0x0;

	/* Replace the CACHE instruction, with a NOP */
	kseg0_opc =
	    CKSEG0ADDR(kvm_mips_translate_guest_kseg0_to_hpa
		       (vcpu, (unsigned long) opc));
	memcpy((void *)kseg0_opc, (void *)&synci_inst, sizeof(uint32_t));
	local_flush_icache_range(kseg0_opc, kseg0_opc + 32);

	return result;
}

/*
 * Address based CACHE instructions are transformed into synci(s). A little
 * heavy for just D-cache invalidates, but avoids an expensive trap
 */
int kvm_mips_trans_cache_va(uint32_t inst, uint32_t *opc,
			    struct kvm_vcpu *vcpu)
{
	int result = 0;
	unsigned long kseg0_opc;
	uint32_t synci_inst = SYNCI_TEMPLATE, base, offset;

	base = (inst >> 21) & 0x1f;
	offset = inst & 0xffff;
	synci_inst |= (base << 21);
	synci_inst |= offset;

	kseg0_opc =
	    CKSEG0ADDR(kvm_mips_translate_guest_kseg0_to_hpa
		       (vcpu, (unsigned long) opc));
	memcpy((void *)kseg0_opc, (void *)&synci_inst, sizeof(uint32_t));
	local_flush_icache_range(kseg0_opc, kseg0_opc + 32);

	return result;
}

int kvm_mips_trans_mfc0(uint32_t inst, uint32_t *opc, struct kvm_vcpu *vcpu)
{
	int32_t rt, rd, sel;
	uint32_t mfc0_inst;
	unsigned long kseg0_opc, flags;

	rt = (inst >> 16) & 0x1f;
	rd = (inst >> 11) & 0x1f;
	sel = inst & 0x7;

	if ((rd == MIPS_CP0_ERRCTL) && (sel == 0)) {
		mfc0_inst = CLEAR_TEMPLATE;
		mfc0_inst |= ((rt & 0x1f) << 16);
	} else {
		mfc0_inst = LW_TEMPLATE;
		mfc0_inst |= ((rt & 0x1f) << 16);
		mfc0_inst |=
		    offsetof(struct mips_coproc,
			     reg[rd][sel]) + offsetof(struct kvm_mips_commpage,
						      cop0);
	}

	if (KVM_GUEST_KSEGX(opc) == KVM_GUEST_KSEG0) {
		kseg0_opc =
		    CKSEG0ADDR(kvm_mips_translate_guest_kseg0_to_hpa
			       (vcpu, (unsigned long) opc));
		memcpy((void *)kseg0_opc, (void *)&mfc0_inst, sizeof(uint32_t));
		local_flush_icache_range(kseg0_opc, kseg0_opc + 32);
	} else if (KVM_GUEST_KSEGX((unsigned long) opc) == KVM_GUEST_KSEG23) {
		local_irq_save(flags);
		memcpy((void *)opc, (void *)&mfc0_inst, sizeof(uint32_t));
		local_flush_icache_range((unsigned long)opc,
					 (unsigned long)opc + 32);
		local_irq_restore(flags);
	} else {
		kvm_err("%s: Invalid address: %p\n", __func__, opc);
		return -EFAULT;
	}

	return 0;
}

int kvm_mips_trans_mtc0(uint32_t inst, uint32_t *opc, struct kvm_vcpu *vcpu)
{
	int32_t rt, rd, sel;
	uint32_t mtc0_inst = SW_TEMPLATE;
	unsigned long kseg0_opc, flags;

	rt = (inst >> 16) & 0x1f;
	rd = (inst >> 11) & 0x1f;
	sel = inst & 0x7;

	mtc0_inst |= ((rt & 0x1f) << 16);
	mtc0_inst |=
	    offsetof(struct mips_coproc,
		     reg[rd][sel]) + offsetof(struct kvm_mips_commpage, cop0);

	if (KVM_GUEST_KSEGX(opc) == KVM_GUEST_KSEG0) {
		kseg0_opc =
		    CKSEG0ADDR(kvm_mips_translate_guest_kseg0_to_hpa
			       (vcpu, (unsigned long) opc));
		memcpy((void *)kseg0_opc, (void *)&mtc0_inst, sizeof(uint32_t));
		local_flush_icache_range(kseg0_opc, kseg0_opc + 32);
	} else if (KVM_GUEST_KSEGX((unsigned long) opc) == KVM_GUEST_KSEG23) {
		local_irq_save(flags);
		memcpy((void *)opc, (void *)&mtc0_inst, sizeof(uint32_t));
		local_flush_icache_range((unsigned long)opc,
					 (unsigned long)opc + 32);
		local_irq_restore(flags);
	} else {
		kvm_err("%s: Invalid address: %p\n", __func__, opc);
		return -EFAULT;
	}

	return 0;
}
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