Commit 5be05c35 authored by Heiko Carstens's avatar Heiko Carstens Committed by Vasily Gorbik
Browse files

s390/mm,fault: improve readability by using teid union 



Get rid of some magic numbers, and use the teid union and also some
ptrace PSW defines to improve readability.

Reviewed-by: default avatarClaudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
Signed-off-by: default avatarVasily Gorbik <gor@linux.ibm.com>
parent 44ae7663

arch/s390/mm/fault.c

+23 −26
Original line number Diff line number Diff line
@@ -36,6 +36,8 @@ 
#include <linux/kfence.h>

#include <asm/asm-extable.h>

#include <asm/asm-offsets.h>

#include <asm/ptrace.h>

#include <asm/fault.h>

#include <asm/diag.h>

#include <asm/gmap.h>

#include <asm/irq.h>
@@ -43,8 +45,6 @@ 
#include <asm/uv.h>

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



#define __FAIL_ADDR_MASK -4096L



/*

 * Allocate private vm_fault_reason from top.

 * Please make sure it won't collide with vm_fault_reason.
@@ -76,11 +76,9 @@ early_initcall(fault_init); 
 */

static enum fault_type get_fault_type(struct pt_regs *regs)

{

	unsigned long trans_exc_code;

	union teid teid = { .val = regs->int_parm_long };



	trans_exc_code = regs->int_parm_long & 3;

	/* Primary address space */

	if (likely(trans_exc_code == 0)) {

	if (likely(teid.as == PSW_BITS_AS_PRIMARY)) {

		if (user_mode(regs))

			return USER_FAULT;

		if (!IS_ENABLED(CONFIG_PGSTE))
@@ -89,10 +87,10 @@ static enum fault_type get_fault_type(struct pt_regs *regs) 
			return GMAP_FAULT;

		return KERNEL_FAULT;

	}

	if (trans_exc_code == 2)

	if (teid.as == PSW_BITS_AS_SECONDARY)

		return USER_FAULT;

	/* Access register mode, not used in the kernel */

	if (trans_exc_code == 1)

	if (teid.as == PSW_BITS_AS_ACCREG)

		return USER_FAULT;

	/* Home space -> access via kernel ASCE */

	return KERNEL_FAULT;
@@ -100,17 +98,17 @@ static enum fault_type get_fault_type(struct pt_regs *regs) 


static unsigned long get_fault_address(struct pt_regs *regs)

{

	unsigned long trans_exc_code = regs->int_parm_long;

	union teid teid = { .val = regs->int_parm_long };



	return trans_exc_code & __FAIL_ADDR_MASK;

	return teid.addr * PAGE_SIZE;

}



static __always_inline bool fault_is_write(struct pt_regs *regs)

{

	unsigned long trans_exc_code = regs->int_parm_long;

	union teid teid = { .val = regs->int_parm_long };



	if (static_branch_likely(&have_store_indication))

		return (trans_exc_code & 0xc00) == 0x400;

		return teid.fsi == TEID_FSI_STORE;

	return false;

}
@@ -176,22 +174,23 @@ static void dump_pagetable(unsigned long asce, unsigned long address) 


static void dump_fault_info(struct pt_regs *regs)

{

	union teid teid = { .val = regs->int_parm_long };

	unsigned long asce;



	pr_alert("Failing address: %016lx TEID: %016lx\n",

		 get_fault_address(regs), regs->int_parm_long);

		 get_fault_address(regs), teid.val);

	pr_alert("Fault in ");

	switch (regs->int_parm_long & 3) {

	case 3:

	switch (teid.as) {

	case PSW_BITS_AS_HOME:

		pr_cont("home space ");

		break;

	case 2:

	case PSW_BITS_AS_SECONDARY:

		pr_cont("secondary space ");

		break;

	case 1:

	case PSW_BITS_AS_ACCREG:

		pr_cont("access register ");

		break;

	case 0:

	case PSW_BITS_AS_PRIMARY:

		pr_cont("primary space ");

		break;

	}
@@ -497,11 +496,10 @@ static inline vm_fault_t do_exception(struct pt_regs *regs, int access) 


void do_protection_exception(struct pt_regs *regs)

{

	unsigned long trans_exc_code;

	union teid teid = { .val = regs->int_parm_long };

	vm_fault_t fault;

	int access;



	trans_exc_code = regs->int_parm_long;

	/*

	 * Protection exceptions are suppressing, decrement psw address.

	 * The exception to this rule are aborted transactions, for these
@@ -514,13 +512,12 @@ void do_protection_exception(struct pt_regs *regs) 
	 * as a special case because the translation exception code

	 * field is not guaranteed to contain valid data in this case.

	 */

	if (unlikely(!(trans_exc_code & 4))) {

	if (unlikely(!teid.b61)) {

		do_low_address(regs);

		return;

	}

	if (unlikely(MACHINE_HAS_NX && (trans_exc_code & 0x80))) {

		regs->int_parm_long = (trans_exc_code & ~PAGE_MASK) |

					(regs->psw.addr & PAGE_MASK);

	if (unlikely(MACHINE_HAS_NX && teid.b56)) {

		regs->int_parm_long = (teid.addr * PAGE_SIZE) | (regs->psw.addr & PAGE_MASK);

		access = VM_EXEC;

		fault = VM_FAULT_BADACCESS;

	} else {
@@ -548,6 +545,7 @@ NOKPROBE_SYMBOL(do_dat_exception); 


void do_secure_storage_access(struct pt_regs *regs)

{

	union teid teid = { .val = regs->int_parm_long };

	unsigned long addr = get_fault_address(regs);

	struct vm_area_struct *vma;

	struct mm_struct *mm;
@@ -561,8 +559,7 @@ void do_secure_storage_access(struct pt_regs *regs) 
	 * process. Bit 61 is not reliable without the misc UV feature,

	 * therefore this needs to be checked too.

	 */

	if (uv_has_feature(BIT_UV_FEAT_MISC) &&

	    !test_bit_inv(61, &regs->int_parm_long)) {

	if (uv_has_feature(BIT_UV_FEAT_MISC) && !teid.b61) {

		/*

		 * When this happens, userspace did something that it

		 * was not supposed to do, e.g. branching into secure