Commit e41ba111 authored by Sven Schnelle's avatar Sven Schnelle Committed by Heiko Carstens
Browse files

s390: add support for KFENCE 



Signed-off-by: default avatarSven Schnelle <svens@linux.ibm.com>
[hca@linux.ibm.com: simplify/rework code]
Link: https://lore.kernel.org/r/20210728190254.3921642-4-hca@linux.ibm.com


Signed-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
parent f99e12b2

arch/s390/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -138,6 +138,7 @@ config S390 
	select HAVE_ARCH_JUMP_LABEL_RELATIVE

	select HAVE_ARCH_KASAN

	select HAVE_ARCH_KASAN_VMALLOC

	select HAVE_ARCH_KFENCE

	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET

	select HAVE_ARCH_SECCOMP_FILTER

	select HAVE_ARCH_SOFT_DIRTY

arch/s390/include/asm/kfence.h

0 → 100644
+42 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */



#ifndef _ASM_S390_KFENCE_H

#define _ASM_S390_KFENCE_H



#include <linux/mm.h>

#include <linux/kfence.h>

#include <asm/set_memory.h>

#include <asm/page.h>



void __kernel_map_pages(struct page *page, int numpages, int enable);



static __always_inline bool arch_kfence_init_pool(void)

{

	return true;

}



#define arch_kfence_test_address(addr) ((addr) & PAGE_MASK)



/*

 * Do not split kfence pool to 4k mapping with arch_kfence_init_pool(),

 * but earlier where page table allocations still happen with memblock.

 * Reason is that arch_kfence_init_pool() gets called when the system

 * is still in a limbo state - disabling and enabling bottom halves is

 * not yet allowed, but that is what our page_table_alloc() would do.

 */

static __always_inline void kfence_split_mapping(void)

{

#ifdef CONFIG_KFENCE

	unsigned long pool_pages = KFENCE_POOL_SIZE >> PAGE_SHIFT;



	set_memory_4k((unsigned long)__kfence_pool, pool_pages);

#endif

}



static inline bool kfence_protect_page(unsigned long addr, bool protect)

{

	__kernel_map_pages(virt_to_page(addr), 1, !protect);

	return true;

}



#endif /* _ASM_S390_KFENCE_H */

arch/s390/mm/fault.c

+7 −2
Original line number Diff line number Diff line
@@ -31,6 +31,7 @@ 
#include <linux/kprobes.h>

#include <linux/uaccess.h>

#include <linux/hugetlb.h>

#include <linux/kfence.h>

#include <asm/asm-offsets.h>

#include <asm/diag.h>

#include <asm/gmap.h>
@@ -356,6 +357,7 @@ static inline vm_fault_t do_exception(struct pt_regs *regs, int access) 
	unsigned long address;

	unsigned int flags;

	vm_fault_t fault;

	bool is_write;



	tsk = current;

	/*
@@ -369,6 +371,8 @@ static inline vm_fault_t do_exception(struct pt_regs *regs, int access) 


	mm = tsk->mm;

	trans_exc_code = regs->int_parm_long;

	address = trans_exc_code & __FAIL_ADDR_MASK;

	is_write = (trans_exc_code & store_indication) == 0x400;



	/*

	 * Verify that the fault happened in user space, that
@@ -379,6 +383,8 @@ static inline vm_fault_t do_exception(struct pt_regs *regs, int access) 
	type = get_fault_type(regs);

	switch (type) {

	case KERNEL_FAULT:

		if (kfence_handle_page_fault(address, is_write, regs))

			return 0;

		goto out;

	case USER_FAULT:

	case GMAP_FAULT:
@@ -387,12 +393,11 @@ static inline vm_fault_t do_exception(struct pt_regs *regs, int access) 
		break;

	}



	address = trans_exc_code & __FAIL_ADDR_MASK;

	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);

	flags = FAULT_FLAG_DEFAULT;

	if (user_mode(regs))

		flags |= FAULT_FLAG_USER;

	if (access == VM_WRITE || (trans_exc_code & store_indication) == 0x400)

	if (access == VM_WRITE || is_write)

		flags |= FAULT_FLAG_WRITE;

	mmap_read_lock(mm);

arch/s390/mm/init.c

+2 −1
Original line number Diff line number Diff line
@@ -34,6 +34,7 @@ 
#include <asm/processor.h>

#include <linux/uaccess.h>

#include <asm/pgalloc.h>

#include <asm/kfence.h>

#include <asm/ptdump.h>

#include <asm/dma.h>

#include <asm/lowcore.h>
@@ -200,7 +201,7 @@ void __init mem_init(void) 
        high_memory = (void *) __va(max_low_pfn * PAGE_SIZE);



	pv_init();



	kfence_split_mapping();

	/* Setup guest page hinting */

	cmma_init();

arch/s390/mm/pageattr.c

+2 −1
Original line number Diff line number Diff line
@@ -8,6 +8,7 @@ 
#include <asm/cacheflush.h>

#include <asm/facility.h>

#include <asm/pgalloc.h>

#include <asm/kfence.h>

#include <asm/page.h>

#include <asm/set_memory.h>
@@ -326,7 +327,7 @@ int __set_memory(unsigned long addr, int numpages, unsigned long flags) 
	return change_page_attr(addr, addr + numpages * PAGE_SIZE, flags);

}



#ifdef CONFIG_DEBUG_PAGEALLOC

#if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KFENCE)



static void ipte_range(pte_t *pte, unsigned long address, int nr)

{