Commit ad5728ce authored by Kees Cook's avatar Kees Cook Committed by Martin Schwidefsky
Browse files

RAID/s390: Remove VLA usage 

In the quest to remove all stack VLA usage from the kernel[1], this moves
the "$#" replacement from being an argument to being inside the function,
which avoids generating VLAs.

[1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com



Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent d2f2df69

lib/raid6/s390vx.uc

+18 −16
Original line number Diff line number Diff line
@@ -55,22 +55,24 @@ static inline void XOR(int x, int y, int z) 
	asm volatile ("VX %0,%1,%2" : : "i" (x), "i" (y), "i" (z));

}



static inline void LOAD_DATA(int x, int n, u8 *ptr)

static inline void LOAD_DATA(int x, u8 *ptr)

{

	typedef struct { u8 _[16*n]; } addrtype;

	typedef struct { u8 _[16 * $#]; } addrtype;

	register addrtype *__ptr asm("1") = (addrtype *) ptr;



	asm volatile ("VLM %2,%3,0,%r1"

		      : : "m" (*__ptr), "a" (__ptr), "i" (x), "i" (x + n - 1));

		      : : "m" (*__ptr), "a" (__ptr), "i" (x),

			  "i" (x + $# - 1));

}



static inline void STORE_DATA(int x, int n, u8 *ptr)

static inline void STORE_DATA(int x, u8 *ptr)

{

	typedef struct { u8 _[16*n]; } addrtype;

	typedef struct { u8 _[16 * $#]; } addrtype;

	register addrtype *__ptr asm("1") = (addrtype *) ptr;



	asm volatile ("VSTM %2,%3,0,1"

		      : "=m" (*__ptr) : "a" (__ptr), "i" (x), "i" (x + n - 1));

		      : "=m" (*__ptr) : "a" (__ptr), "i" (x),

			"i" (x + $# - 1));

}



static inline void COPY_VEC(int x, int y)
@@ -93,19 +95,19 @@ static void raid6_s390vx$#_gen_syndrome(int disks, size_t bytes, void **ptrs) 
	q = dptr[z0 + 2];	/* RS syndrome */



	for (d = 0; d < bytes; d += $#*NSIZE) {

		LOAD_DATA(0,$#,&dptr[z0][d]);

		LOAD_DATA(0,&dptr[z0][d]);

		COPY_VEC(8+$$,0+$$);

		for (z = z0 - 1; z >= 0; z--) {

			MASK(16+$$,8+$$);

			AND(16+$$,16+$$,25);

			SHLBYTE(8+$$,8+$$);

			XOR(8+$$,8+$$,16+$$);

			LOAD_DATA(16,$#,&dptr[z][d]);

			LOAD_DATA(16,&dptr[z][d]);

			XOR(0+$$,0+$$,16+$$);

			XOR(8+$$,8+$$,16+$$);

		}

		STORE_DATA(0,$#,&p[d]);

		STORE_DATA(8,$#,&q[d]);

		STORE_DATA(0,&p[d]);

		STORE_DATA(8,&q[d]);

	}

	kernel_fpu_end(&vxstate, KERNEL_VXR);

}
@@ -127,14 +129,14 @@ static void raid6_s390vx$#_xor_syndrome(int disks, int start, int stop, 


	for (d = 0; d < bytes; d += $#*NSIZE) {

		/* P/Q data pages */

		LOAD_DATA(0,$#,&dptr[z0][d]);

		LOAD_DATA(0,&dptr[z0][d]);

		COPY_VEC(8+$$,0+$$);

		for (z = z0 - 1; z >= start; z--) {

			MASK(16+$$,8+$$);

			AND(16+$$,16+$$,25);

			SHLBYTE(8+$$,8+$$);

			XOR(8+$$,8+$$,16+$$);

			LOAD_DATA(16,$#,&dptr[z][d]);

			LOAD_DATA(16,&dptr[z][d]);

			XOR(0+$$,0+$$,16+$$);

			XOR(8+$$,8+$$,16+$$);

		}
@@ -145,12 +147,12 @@ static void raid6_s390vx$#_xor_syndrome(int disks, int start, int stop, 
			SHLBYTE(8+$$,8+$$);

			XOR(8+$$,8+$$,16+$$);

		}

		LOAD_DATA(16,$#,&p[d]);

		LOAD_DATA(16,&p[d]);

		XOR(16+$$,16+$$,0+$$);

		STORE_DATA(16,$#,&p[d]);

		LOAD_DATA(16,$#,&q[d]);

		STORE_DATA(16,&p[d]);

		LOAD_DATA(16,&q[d]);

		XOR(16+$$,16+$$,8+$$);

		STORE_DATA(16,$#,&q[d]);

		STORE_DATA(16,&q[d]);

	}

	kernel_fpu_end(&vxstate, KERNEL_VXR);

}