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=qpxydaacu1rq...@mail.gmail.com Cc: Martin Schwidefsky <schwidef...@de.ibm.com> Cc: Philippe Ombredanne <pombreda...@nexb.com> Signed-off-by: Kees Cook <keesc...@chromium.org> --- Resend due to typo in To/Cc --- lib/raid6/s390vx.uc | 34 ++++++++++++++++++---------------- 1 file changed, 18 insertions(+), 16 deletions(-) diff --git a/lib/raid6/s390vx.uc b/lib/raid6/s390vx.uc index 140fa8bb5c23..914ebe98fc21 100644 --- 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); } -- 2.17.1 -- Kees Cook Pixel Security
