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s390/mm,fault: simplify kfence fault handling

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do_no_context() can be simplified by removing its fault parameter,
which is only used to decide if kfence_handle_page_fault() should be
called.

If the fault happened within the kernel space it is ok to always check
if this happened on a page which was unmapped because of the kfence
feature. Limiting the check to the VM_FAULT_BADCONTEXT case doesn't
add any value.

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 09:40:48 +02:00 committed by Vasily Gorbik
parent 64ea33fb09
commit 0f1a14e034
1 changed files with 8 additions and 8 deletions
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16
arch/s390/mm/fault.c
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@ -234,7 +234,7 @@ static void do_sigsegv(struct pt_regs *regs, int si_code)
force_sig_fault(SIGSEGV, si_code, (void __user *)get_fault_address(regs));
}
static void do_no_context(struct pt_regs *regs, vm_fault_t fault)
static void do_no_context(struct pt_regs *regs)
{
enum fault_type fault_type;
unsigned long address;
@ -243,7 +243,7 @@ static void do_no_context(struct pt_regs *regs, vm_fault_t fault)
if (fixup_exception(regs))
return;
fault_type = get_fault_type(regs);
if ((fault_type == KERNEL_FAULT) && (fault == VM_FAULT_BADCONTEXT)) {
if (fault_type == KERNEL_FAULT) {
address = get_fault_address(regs);
is_write = fault_is_write(regs);
if (kfence_handle_page_fault(address, is_write, regs))
@ -279,28 +279,28 @@ static void do_fault_error(struct pt_regs *regs, vm_fault_t fault)
}
fallthrough;
case VM_FAULT_BADCONTEXT:
do_no_context(regs, fault);
do_no_context(regs);
break;
case VM_FAULT_SIGNAL:
if (!user_mode(regs))
do_no_context(regs, fault);
do_no_context(regs);
break;
default: /* fault & VM_FAULT_ERROR */
if (fault & VM_FAULT_OOM) {
if (!user_mode(regs))
do_no_context(regs, fault);
do_no_context(regs);
else
pagefault_out_of_memory();
} else if (fault & VM_FAULT_SIGSEGV) {
/* Kernel mode? Handle exceptions or die */
if (!user_mode(regs))
do_no_context(regs, fault);
do_no_context(regs);
else
do_sigsegv(regs, SEGV_MAPERR);
} else if (fault & VM_FAULT_SIGBUS) {
/* Kernel mode? Handle exceptions or die */
if (!user_mode(regs))
do_no_context(regs, fault);
do_no_context(regs);
else
do_sigbus(regs);
} else {
@ -497,7 +497,7 @@ void do_protection_exception(struct pt_regs *regs)
* Low-address protection in kernel mode means
* NULL pointer write access in kernel mode.
*/
return do_no_context(regs, VM_FAULT_BADACCESS);
return do_no_context(regs);
}
if (unlikely(MACHINE_HAS_NX && teid.b56)) {
regs->int_parm_long = (teid.addr * PAGE_SIZE) | (regs->psw.addr & PAGE_MASK);