Commit 084ea4d6 authored by Vasily Gorbik's avatar Vasily Gorbik Committed by Christian Borntraeger
Browse files

s390/mm: add (non)secure page access exceptions handlers 



Add exceptions handlers performing transparent transition of non-secure
pages to secure (import) upon guest access and secure pages to
non-secure (export) upon hypervisor access.

Signed-off-by: default avatarVasily Gorbik <gor@linux.ibm.com>
[frankja@linux.ibm.com: adding checks for failures]
Signed-off-by: default avatarJanosch Frank <frankja@linux.ibm.com>
[imbrenda@linux.ibm.com:  adding a check for gmap fault]
Signed-off-by: default avatarClaudio Imbrenda <imbrenda@linux.ibm.com>
Acked-by: default avatarDavid Hildenbrand <david@redhat.com>
Acked-by: default avatarCornelia Huck <cohuck@redhat.com>
Reviewed-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
[borntraeger@de.ibm.com: patch merging, splitting, fixing]
Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
parent 214d9bbc

arch/s390/kernel/entry.h

+2 −0
Original line number Diff line number Diff line
@@ -24,6 +24,8 @@ asmlinkage void do_syscall_trace_exit(struct pt_regs *regs); 


void do_protection_exception(struct pt_regs *regs);

void do_dat_exception(struct pt_regs *regs);

void do_secure_storage_access(struct pt_regs *regs);

void do_non_secure_storage_access(struct pt_regs *regs);



void addressing_exception(struct pt_regs *regs);

void data_exception(struct pt_regs *regs);

arch/s390/kernel/pgm_check.S

+2 −2
Original line number Diff line number Diff line
@@ -78,8 +78,8 @@ PGM_CHECK(do_dat_exception) /* 39 */ 
PGM_CHECK(do_dat_exception)		/* 3a */

PGM_CHECK(do_dat_exception)		/* 3b */

PGM_CHECK_DEFAULT			/* 3c */

PGM_CHECK_DEFAULT			/* 3d */

PGM_CHECK_DEFAULT			/* 3e */

PGM_CHECK(do_secure_storage_access)	/* 3d */

PGM_CHECK(do_non_secure_storage_access)	/* 3e */

PGM_CHECK_DEFAULT			/* 3f */

PGM_CHECK(monitor_event_exception)	/* 40 */

PGM_CHECK_DEFAULT			/* 41 */

arch/s390/mm/fault.c

+78 −0
Original line number Diff line number Diff line
@@ -38,6 +38,7 @@ 
#include <asm/irq.h>

#include <asm/mmu_context.h>

#include <asm/facility.h>

#include <asm/uv.h>

#include "../kernel/entry.h"



#define __FAIL_ADDR_MASK -4096L
@@ -816,3 +817,80 @@ out_extint: 
early_initcall(pfault_irq_init);



#endif /* CONFIG_PFAULT */



#if IS_ENABLED(CONFIG_PGSTE)

void do_secure_storage_access(struct pt_regs *regs)

{

	unsigned long addr = regs->int_parm_long & __FAIL_ADDR_MASK;

	struct vm_area_struct *vma;

	struct mm_struct *mm;

	struct page *page;

	int rc;



	switch (get_fault_type(regs)) {

	case USER_FAULT:

		mm = current->mm;

		down_read(&mm->mmap_sem);

		vma = find_vma(mm, addr);

		if (!vma) {

			up_read(&mm->mmap_sem);

			do_fault_error(regs, VM_READ | VM_WRITE, VM_FAULT_BADMAP);

			break;

		}

		page = follow_page(vma, addr, FOLL_WRITE | FOLL_GET);

		if (IS_ERR_OR_NULL(page)) {

			up_read(&mm->mmap_sem);

			break;

		}

		if (arch_make_page_accessible(page))

			send_sig(SIGSEGV, current, 0);

		put_page(page);

		up_read(&mm->mmap_sem);

		break;

	case KERNEL_FAULT:

		page = phys_to_page(addr);

		if (unlikely(!try_get_page(page)))

			break;

		rc = arch_make_page_accessible(page);

		put_page(page);

		if (rc)

			BUG();

		break;

	case VDSO_FAULT:

		/* fallthrough */

	case GMAP_FAULT:

		/* fallthrough */

	default:

		do_fault_error(regs, VM_READ | VM_WRITE, VM_FAULT_BADMAP);

		WARN_ON_ONCE(1);

	}

}

NOKPROBE_SYMBOL(do_secure_storage_access);



void do_non_secure_storage_access(struct pt_regs *regs)

{

	unsigned long gaddr = regs->int_parm_long & __FAIL_ADDR_MASK;

	struct gmap *gmap = (struct gmap *)S390_lowcore.gmap;



	if (get_fault_type(regs) != GMAP_FAULT) {

		do_fault_error(regs, VM_READ | VM_WRITE, VM_FAULT_BADMAP);

		WARN_ON_ONCE(1);

		return;

	}



	if (gmap_convert_to_secure(gmap, gaddr) == -EINVAL)

		send_sig(SIGSEGV, current, 0);

}

NOKPROBE_SYMBOL(do_non_secure_storage_access);



#else

void do_secure_storage_access(struct pt_regs *regs)

{

	default_trap_handler(regs);

}



void do_non_secure_storage_access(struct pt_regs *regs)

{

	default_trap_handler(regs);

}

#endif

CRA Git | Maintained and supported by SUSTech CRA and CCSE