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: Kees Cook <keescook@chromium.org>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/lib/raid6/s390vx.uc b/lib/raid6/s390vx.uc
index 140fa8b..914ebe9 100644 (file)
--- a/lib/raid6/s390vx.uc
+++ b/lib/raid6/s390vx.uc
@@ -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);
 }