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

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

Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
This commit is contained in:
Heiko Carstens 2023-10-12 09:40:43 +02:00 committed by Vasily Gorbik
parent 44ae766353
commit 5be05c35e7
1 changed files with 23 additions and 26 deletions
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49
arch/s390/mm/fault.c
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@ -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 @@ bad:
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 @@ out:
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