Commit bf53ede0 authored by Christophe Leroy (CS GROUP)'s avatar Christophe Leroy (CS GROUP) Committed by Madhavan Srinivasan
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powerpc/align: Convert emulate_spe() to scoped user access 



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

Convert emulate_spe() 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/4ff83cb240da4e2d0c34e2bce4b8b6ef19a33777.1773136880.git.chleroy@kernel.org
parent 679fa9c7

arch/powerpc/kernel/align.c

+33 −42
Original line number Diff line number Diff line
@@ -165,25 +165,23 @@ static int emulate_spe(struct pt_regs *regs, unsigned int reg, 
		temp.ll = data.ll = 0;

		p = addr;



		if (!user_read_access_begin(addr, nb))

			return -EFAULT;



		scoped_user_read_access_size(addr, nb, efault) {

			switch (nb) {

			case 8:

			unsafe_get_user(temp.v[0], p++, Efault_read);

			unsafe_get_user(temp.v[1], p++, Efault_read);

			unsafe_get_user(temp.v[2], p++, Efault_read);

			unsafe_get_user(temp.v[3], p++, Efault_read);

				unsafe_get_user(temp.v[0], p++, efault);

				unsafe_get_user(temp.v[1], p++, efault);

				unsafe_get_user(temp.v[2], p++, efault);

				unsafe_get_user(temp.v[3], p++, efault);

				fallthrough;

			case 4:

			unsafe_get_user(temp.v[4], p++, Efault_read);

			unsafe_get_user(temp.v[5], p++, Efault_read);

				unsafe_get_user(temp.v[4], p++, efault);

				unsafe_get_user(temp.v[5], p++, efault);

				fallthrough;

			case 2:

			unsafe_get_user(temp.v[6], p++, Efault_read);

			unsafe_get_user(temp.v[7], p++, Efault_read);

				unsafe_get_user(temp.v[6], p++, efault);

				unsafe_get_user(temp.v[7], p++, efault);

			}

		}

		user_read_access_end();



		switch (instr) {

		case EVLDD:
@@ -252,25 +250,23 @@ static int emulate_spe(struct pt_regs *regs, unsigned int reg, 
	if (flags & ST) {

		p = addr;



		if (!user_write_access_begin(addr, nb))

			return -EFAULT;



		scoped_user_write_access_size(addr, nb, efault) {

			switch (nb) {

			case 8:

			unsafe_put_user(data.v[0], p++, Efault_write);

			unsafe_put_user(data.v[1], p++, Efault_write);

			unsafe_put_user(data.v[2], p++, Efault_write);

			unsafe_put_user(data.v[3], p++, Efault_write);

				unsafe_put_user(data.v[0], p++, efault);

				unsafe_put_user(data.v[1], p++, efault);

				unsafe_put_user(data.v[2], p++, efault);

				unsafe_put_user(data.v[3], p++, efault);

				fallthrough;

			case 4:

			unsafe_put_user(data.v[4], p++, Efault_write);

			unsafe_put_user(data.v[5], p++, Efault_write);

				unsafe_put_user(data.v[4], p++, efault);

				unsafe_put_user(data.v[5], p++, efault);

				fallthrough;

			case 2:

			unsafe_put_user(data.v[6], p++, Efault_write);

			unsafe_put_user(data.v[7], p++, Efault_write);

				unsafe_put_user(data.v[6], p++, efault);

				unsafe_put_user(data.v[7], p++, efault);

			}

		}

		user_write_access_end();

	} else {

		*evr = data.w[0];

		regs->gpr[reg] = data.w[1];
@@ -278,12 +274,7 @@ static int emulate_spe(struct pt_regs *regs, unsigned int reg, 


	return 1;



Efault_read:

	user_read_access_end();

	return -EFAULT;



Efault_write:

	user_write_access_end();

efault:

	return -EFAULT;

}

#endif /* CONFIG_SPE */