Commit 7c194d84 authored by Heiko Carstens's avatar Heiko Carstens Committed by Vasily Gorbik
Browse files

s390/mm,fault: remove VM_FAULT_BADMAP and VM_FAULT_BADACCESS 



Remove the last two private vm_fault reasons: VM_FAULT_BADMAP and
VM_FAULT_BADACCESS.

In order to achieve this add an si_code parameter to do_no_context()
and it's wrappers and directly call the wrappers instead of relying on
do_fault_error() handling.

Signed-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
Signed-off-by: default avatarVasily Gorbik <gor@linux.ibm.com>
parent b61a0922

arch/s390/mm/fault.c

+51 −85
Original line number Diff line number Diff line
@@ -45,13 +45,6 @@ 
#include <asm/uv.h>

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



/*

 * Allocate private vm_fault_reason from top.

 * Please make sure it won't collide with vm_fault_reason.

 */

#define VM_FAULT_BADMAP		((__force vm_fault_t)0x40000000)

#define VM_FAULT_BADACCESS	((__force vm_fault_t)0x20000000)



enum fault_type {

	KERNEL_FAULT,

	USER_FAULT,
@@ -232,12 +225,17 @@ 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)

static void do_no_context(struct pt_regs *regs, int si_code)

{

	enum fault_type fault_type;

	unsigned long address;

	bool is_write;



	if (user_mode(regs)) {

		if (WARN_ON_ONCE(!si_code))

			si_code = SEGV_MAPERR;

		return do_sigsegv(regs, si_code);

	}

	if (fixup_exception(regs))

		return;

	fault_type = get_fault_type(regs);
@@ -255,17 +253,17 @@ static void do_no_context(struct pt_regs *regs) 
	die(regs, "Oops");

}



static inline void handle_fault_error_nolock(struct pt_regs *regs)

static inline void handle_fault_error_nolock(struct pt_regs *regs, int si_code)

{

	do_no_context(regs);

	do_no_context(regs, si_code);

}



static void handle_fault_error(struct pt_regs *regs)

static void handle_fault_error(struct pt_regs *regs, int si_code)

{

	struct mm_struct *mm = current->mm;



	mmap_read_unlock(mm);

	handle_fault_error_nolock(regs);

	handle_fault_error_nolock(regs, si_code);

}



static void do_sigbus(struct pt_regs *regs)
@@ -275,44 +273,27 @@ static void do_sigbus(struct pt_regs *regs) 


static void do_fault_error(struct pt_regs *regs, vm_fault_t fault)

{

	int si_code;



	switch (fault) {

	case VM_FAULT_BADACCESS:

	case VM_FAULT_BADMAP:

		/* Bad memory access. Check if it is kernel or user space. */

		if (user_mode(regs)) {

			/* User mode accesses just cause a SIGSEGV */

			si_code = (fault == VM_FAULT_BADMAP) ?

				SEGV_MAPERR : SEGV_ACCERR;

			do_sigsegv(regs, si_code);

			break;

		}

		do_no_context(regs);

		break;

	default: /* fault & VM_FAULT_ERROR */

	/* fault & VM_FAULT_ERROR */

	if (fault & VM_FAULT_OOM) {

		if (!user_mode(regs))

				do_no_context(regs);

			do_no_context(regs, 0);

		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);

			do_no_context(regs, 0);

		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);

			do_no_context(regs, 0);

		else

			do_sigbus(regs);

	} else {

		BUG();

	}

		break;

	}

}



/*
@@ -352,11 +333,11 @@ static void do_exception(struct pt_regs *regs, int access) 
	type = get_fault_type(regs);

	switch (type) {

	case KERNEL_FAULT:

		return handle_fault_error_nolock(regs);

		return handle_fault_error_nolock(regs, 0);

	case USER_FAULT:

	case GMAP_FAULT:

		if (faulthandler_disabled() || !mm)

			return handle_fault_error_nolock(regs);

			return handle_fault_error_nolock(regs, 0);

		break;

	}

	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
@@ -389,7 +370,7 @@ static void do_exception(struct pt_regs *regs, int access) 
	/* Quick path to respond to signals */

	if (fault_signal_pending(fault, regs)) {

		if (!user_mode(regs))

			handle_fault_error_nolock(regs);

			handle_fault_error_nolock(regs, 0);

		return;

	}

lock_mmap:
@@ -401,34 +382,30 @@ static void do_exception(struct pt_regs *regs, int access) 
		current->thread.gmap_write_flag = !!(flags & FAULT_FLAG_WRITE);

		current->thread.gmap_int_code = regs->int_code & 0xffff;

		address = __gmap_translate(gmap, address);

		if (address == -EFAULT) {

			fault = VM_FAULT_BADMAP;

			goto out_up;

		}

		if (address == -EFAULT)

			return handle_fault_error(regs, SEGV_MAPERR);

		if (gmap->pfault_enabled)

			flags |= FAULT_FLAG_RETRY_NOWAIT;

	}

retry:

	fault = VM_FAULT_BADMAP;

	vma = find_vma(mm, address);

	if (!vma)

		goto out_up;

		return handle_fault_error(regs, SEGV_MAPERR);

	if (unlikely(vma->vm_start > address)) {

		if (!(vma->vm_flags & VM_GROWSDOWN))

			goto out_up;

			return handle_fault_error(regs, SEGV_MAPERR);

		vma = expand_stack(mm, address);

		if (!vma)

			goto out;

			return handle_fault_error_nolock(regs, SEGV_MAPERR);

	}

	fault = VM_FAULT_BADACCESS;

	if (unlikely(!(vma->vm_flags & access)))

		goto out_up;

		return handle_fault_error(regs, SEGV_ACCERR);

	fault = handle_mm_fault(vma, address, flags, regs);

	if (fault_signal_pending(fault, regs)) {

		if (flags & FAULT_FLAG_RETRY_NOWAIT)

			mmap_read_unlock(mm);

		if (!user_mode(regs))

			handle_fault_error_nolock(regs);

			handle_fault_error_nolock(regs, 0);

		return;

	}

	/* The fault is fully completed (including releasing mmap lock) */
@@ -449,7 +426,7 @@ static void do_exception(struct pt_regs *regs, int access) 
			 * mmap_lock has not been released

			 */

			current->thread.gmap_pfault = 1;

			return handle_fault_error(regs);

			return handle_fault_error(regs, 0);

		}

		flags &= ~FAULT_FLAG_RETRY_NOWAIT;

		flags |= FAULT_FLAG_TRIED;
@@ -460,10 +437,8 @@ static void do_exception(struct pt_regs *regs, int access) 
	if (IS_ENABLED(CONFIG_PGSTE) && gmap) {

		address =  __gmap_link(gmap, current->thread.gmap_addr,

				       address);

		if (address == -EFAULT) {

			fault = VM_FAULT_BADMAP;

			goto out_up;

		}

		if (address == -EFAULT)

			return handle_fault_error(regs, SEGV_MAPERR);

		if (address == -ENOMEM) {

			fault = VM_FAULT_OOM;

			goto out_up;
@@ -502,12 +477,11 @@ 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);

		return do_no_context(regs, 0);

	}

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

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

		do_fault_error(regs, VM_FAULT_BADACCESS);

		return;

		return handle_fault_error_nolock(regs, SEGV_ACCERR);

	}

	do_exception(regs, VM_WRITE);

}
@@ -560,20 +534,15 @@ void do_secure_storage_access(struct pt_regs *regs) 
		mmap_read_lock(mm);

		addr = __gmap_translate(gmap, addr);

		mmap_read_unlock(mm);

		if (IS_ERR_VALUE(addr)) {

			do_fault_error(regs, VM_FAULT_BADMAP);

			break;

		}

		if (IS_ERR_VALUE(addr))

			return handle_fault_error_nolock(regs, SEGV_MAPERR);

		fallthrough;

	case USER_FAULT:

		mm = current->mm;

		mmap_read_lock(mm);

		vma = find_vma(mm, addr);

		if (!vma) {

			mmap_read_unlock(mm);

			do_fault_error(regs, VM_FAULT_BADMAP);

			break;

		}

		if (!vma)

			return handle_fault_error(regs, SEGV_MAPERR);

		page = follow_page(vma, addr, FOLL_WRITE | FOLL_GET);

		if (IS_ERR_OR_NULL(page)) {

			mmap_read_unlock(mm);
@@ -604,11 +573,8 @@ void do_non_secure_storage_access(struct pt_regs *regs) 
	struct gmap *gmap = (struct gmap *)S390_lowcore.gmap;

	unsigned long gaddr = get_fault_address(regs);



	if (get_fault_type(regs) != GMAP_FAULT) {

		do_fault_error(regs, VM_FAULT_BADMAP);

		WARN_ON_ONCE(1);

		return;

	}

	if (WARN_ON_ONCE(get_fault_type(regs) != GMAP_FAULT))

		return handle_fault_error_nolock(regs, SEGV_MAPERR);

	if (gmap_convert_to_secure(gmap, gaddr) == -EINVAL)

		send_sig(SIGSEGV, current, 0);

}