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: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index 5466a30d1ec4a4490ad1698fa0e183c853518907..bcaac0f939df9045834ff7da6c006d2ffab02a6b 100644 (file)
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -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