Commit cd54714e authored by Christophe Leroy (CS GROUP)'s avatar Christophe Leroy (CS GROUP) Committed by Madhavan Srinivasan
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powerpc/sstep: Convert to scoped user access 



Commit 861574d5 ("powerpc/uaccess: Implement masked user access")
provides optimised user access by avoiding the cost of access_ok().

Convert single step emulation functions to scoped user access to
benefit from masked user access.

Scoped user access also make the code simpler.

Signed-off-by: default avatarChristophe Leroy (CS GROUP) <chleroy@kernel.org>
Signed-off-by: default avatarMadhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/8f2d85bddacff18046096dc255fd94f6a0f8b230.1773137010.git.chleroy@kernel.org
parent bf53ede0

arch/powerpc/lib/sstep.c

+33 −44
Original line number Diff line number Diff line
@@ -329,20 +329,17 @@ __read_mem_aligned(unsigned long *dest, unsigned long ea, int nb, struct pt_regs 
static nokprobe_inline int

read_mem_aligned(unsigned long *dest, unsigned long ea, int nb, struct pt_regs *regs)

{

	int err;

	void __user *uea = (void __user *)ea;



	if (is_kernel_addr(ea))

		return __read_mem_aligned(dest, ea, nb, regs);



	if (user_read_access_begin((void __user *)ea, nb)) {

		err = __read_mem_aligned(dest, ea, nb, regs);

		user_read_access_end();

	} else {

		err = -EFAULT;

		regs->dar = ea;

	}

	scoped_user_read_access_size(uea, nb, efault)

		return __read_mem_aligned(dest, (unsigned long)uea, nb, regs);



	return err;

efault:

	regs->dar = ea;

	return -EFAULT;

}



/*
@@ -385,20 +382,17 @@ static __always_inline int __copy_mem_in(u8 *dest, unsigned long ea, int nb, str 


static nokprobe_inline int copy_mem_in(u8 *dest, unsigned long ea, int nb, struct pt_regs *regs)

{

	int err;

	void __user *uea = (void __user *)ea;



	if (is_kernel_addr(ea))

		return __copy_mem_in(dest, ea, nb, regs);



	if (user_read_access_begin((void __user *)ea, nb)) {

		err = __copy_mem_in(dest, ea, nb, regs);

		user_read_access_end();

	} else {

		err = -EFAULT;

		regs->dar = ea;

	}

	scoped_user_read_access_size(uea, nb, efault)

		return __copy_mem_in(dest, (unsigned long)uea, nb, regs);



	return err;

efault:

	regs->dar = ea;

	return -EFAULT;

}



static nokprobe_inline int read_mem_unaligned(unsigned long *dest,
@@ -465,20 +459,17 @@ __write_mem_aligned(unsigned long val, unsigned long ea, int nb, struct pt_regs 
static nokprobe_inline int

write_mem_aligned(unsigned long val, unsigned long ea, int nb, struct pt_regs *regs)

{

	int err;

	void __user *uea = (void __user *)ea;



	if (is_kernel_addr(ea))

		return __write_mem_aligned(val, ea, nb, regs);



	if (user_write_access_begin((void __user *)ea, nb)) {

		err = __write_mem_aligned(val, ea, nb, regs);

		user_write_access_end();

	} else {

		err = -EFAULT;

		regs->dar = ea;

	}

	scoped_user_write_access_size(uea, nb, efault)

		return __write_mem_aligned(val, (unsigned long)uea, nb, regs);



	return err;

efault:

	regs->dar = ea;

	return -EFAULT;

}



/*
@@ -521,20 +512,17 @@ static __always_inline int __copy_mem_out(u8 *dest, unsigned long ea, int nb, st 


static nokprobe_inline int copy_mem_out(u8 *dest, unsigned long ea, int nb, struct pt_regs *regs)

{

	int err;

	void __user *uea = (void __user *)ea;



	if (is_kernel_addr(ea))

		return __copy_mem_out(dest, ea, nb, regs);



	if (user_write_access_begin((void __user *)ea, nb)) {

		err = __copy_mem_out(dest, ea, nb, regs);

		user_write_access_end();

	} else {

		err = -EFAULT;

		regs->dar = ea;

	}

	scoped_user_write_access_size(uea, nb, efault)

		return __copy_mem_out(dest, (unsigned long)uea, nb, regs);



	return err;

efault:

	regs->dar = ea;

	return -EFAULT;

}



static nokprobe_inline int write_mem_unaligned(unsigned long val,
@@ -1065,6 +1053,7 @@ static __always_inline int __emulate_dcbz(unsigned long ea) 


int emulate_dcbz(unsigned long ea, struct pt_regs *regs)

{

	void __user *uea = (void __user *)ea;

	int err;

	unsigned long size = l1_dcache_bytes();
@@ -1073,20 +1062,20 @@ int emulate_dcbz(unsigned long ea, struct pt_regs *regs) 
	if (!address_ok(regs, ea, size))

		return -EFAULT;



	if (is_kernel_addr(ea)) {

		err = __emulate_dcbz(ea);

	} else if (user_write_access_begin((void __user *)ea, size)) {

	if (is_kernel_addr(ea))

		err = __emulate_dcbz(ea);

		user_write_access_end();

	} else {

		err = -EFAULT;

	}

	else

		scoped_user_write_access_size(uea, size, efault)

			err = __emulate_dcbz((unsigned long)uea);



	if (err)

		regs->dar = ea;





	return err;



efault:

	regs->dar = ea;

	return -EFAULT;

}

NOKPROBE_SYMBOL(emulate_dcbz);