crypto: x86/crc32c - access 32-bit arguments as 32-bit

Fix crc32c-pcl-intel-asm_64.S to access 32-bit arguments as 32-bit
values instead of 64-bit, since the upper bits of the corresponding
64-bit registers are not guaranteed to be zero.  Also update the type of
the length argument to be unsigned int rather than int, as the assembly
code treats it as unsigned.

Note: there haven't been any reports of this bug actually causing
incorrect behavior.  Neither gcc nor clang guarantee zero-extension to
64 bits, but zero-extension is likely to happen in practice because most
instructions that operate on 32-bit registers zero-extend to 64 bits.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/arch/x86/crypto/crc32c-intel_glue.c b/arch/x86/crypto/crc32c-intel_glue.c
index feccb52..52c5d47 100644 (file)
--- a/arch/x86/crypto/crc32c-intel_glue.c
+++ b/arch/x86/crypto/crc32c-intel_glue.c
@@ -41,7 +41,7 @@
  */
 #define CRC32C_PCL_BREAKEVEN   512
 
-asmlinkage unsigned int crc_pcl(const u8 *buffer, int len,
+asmlinkage unsigned int crc_pcl(const u8 *buffer, unsigned int len,
                                unsigned int crc_init);
 #endif /* CONFIG_X86_64 */
 

diff --git a/arch/x86/crypto/crc32c-pcl-intel-asm_64.S b/arch/x86/crypto/crc32c-pcl-intel-asm_64.S
index 466cea4..bbf860e 100644 (file)
--- a/arch/x86/crypto/crc32c-pcl-intel-asm_64.S
+++ b/arch/x86/crypto/crc32c-pcl-intel-asm_64.S
@@ -60,7 +60,7 @@
 # regular CRC code that does not interleave the CRC instructions.
 #define SMALL_SIZE 200
 
-# unsigned int crc_pcl(u8 *buffer, int len, unsigned int crc_init);
+# unsigned int crc_pcl(const u8 *buffer, unsigned int len, unsigned int crc_init);
 
 .text
 SYM_FUNC_START(crc_pcl)
@@ -72,14 +72,11 @@ SYM_FUNC_START(crc_pcl)
 #define    block_0     %rcx
 #define    block_1     %rdx
 #define    block_2     %r11
-#define    len         %rsi
-#define    len_dw      %esi
-#define    len_w       %si
-#define    len_b       %sil
-#define    crc_init_arg %rdx
+#define    len         %esi
+#define    crc_init_arg %edx
 #define    tmp         %rbx
-#define    crc_init    %r8
-#define    crc_init_dw %r8d
+#define    crc_init    %r8d
+#define    crc_init_q  %r8
 #define    crc1                %r9
 #define    crc2                %r10
 
@@ -107,9 +104,9 @@ SYM_FUNC_START(crc_pcl)
        movq    (bufptmp), tmp          # load a quadward from the buffer
        add     %bufp, bufptmp          # align buffer pointer for quadword
                                        # processing
-       sub     %bufp, len              # update buffer length
+       sub     bufp_dw, len            # update buffer length
 .Lalign_loop:
-       crc32b  %bl, crc_init_dw        # compute crc32 of 1-byte
+       crc32b  %bl, crc_init           # compute crc32 of 1-byte
        shr     $8, tmp                 # get next byte
        dec     %bufp
        jne     .Lalign_loop
@@ -121,15 +118,14 @@ SYM_FUNC_START(crc_pcl)
        ################################################################
 
        ## compute num of bytes to be processed
-       movq    len, tmp                # save num bytes in tmp
 
-       cmpq    $128*24, len
+       cmp     $128*24, len
        jae     .Lfull_block
 
 .Lcontinue_block:
        ## len < 128*24
        movq    $2731, %rax             # 2731 = ceil(2^16 / 24)
-       mul     len_dw
+       mul     len
        shrq    $16, %rax
 
        ## eax contains floor(bytes / 24) = num 24-byte chunks to do
@@ -176,7 +172,7 @@ SYM_FUNC_START(crc_pcl)
 LABEL crc_ %i
 .noaltmacro
        ENDBR
-       crc32q   -i*8(block_0), crc_init
+       crc32q   -i*8(block_0), crc_init_q
        crc32q   -i*8(block_1), crc1
        crc32q   -i*8(block_2), crc2
        i=(i-1)
@@ -186,7 +182,7 @@ LABEL crc_ %i
 LABEL crc_ %i
 .noaltmacro
        ENDBR
-       crc32q   -i*8(block_0), crc_init
+       crc32q   -i*8(block_0), crc_init_q
        crc32q   -i*8(block_1), crc1
 # SKIP  crc32  -i*8(block_2), crc2 ; Don't do this one yet
 
@@ -200,9 +196,9 @@ LABEL crc_ %i
        shlq    $3, %rax                        # rax *= 8
        pmovzxdq (%bufp,%rax), %xmm0            # 2 consts: K1:K2
        leal    (%eax,%eax,2), %eax             # rax *= 3 (total *24)
-       subq    %rax, tmp                       # tmp -= rax*24
+       sub     %eax, len                       # len -= rax*24
 
-       movq    crc_init, %xmm1                 # CRC for block 1
+       movq    crc_init_q, %xmm1               # CRC for block 1
        pclmulqdq $0x00, %xmm0, %xmm1           # Multiply by K2
 
        movq    crc1, %xmm2                     # CRC for block 2
@@ -211,8 +207,8 @@ LABEL crc_ %i
        pxor    %xmm2,%xmm1
        movq    %xmm1, %rax
        xor     -i*8(block_2), %rax
-       mov     crc2, crc_init
-       crc32   %rax, crc_init
+       mov     crc2, crc_init_q
+       crc32   %rax, crc_init_q
 
        ################################################################
        ## 5) Check for end:
@@ -220,10 +216,9 @@ LABEL crc_ %i
 
 LABEL crc_ 0
        ENDBR
-       mov     tmp, len
-       cmp     $128*24, tmp
+       cmp     $128*24, len
        jae     .Lfull_block
-       cmp     $SMALL_SIZE, tmp
+       cmp     $SMALL_SIZE, len
        jae     .Lcontinue_block
 
        #######################################################################
@@ -232,30 +227,30 @@ LABEL crc_ 0
 .Lsmall:
        test    len, len
        jz      .Ldone
-       mov     len_dw, %eax
+       mov     len, %eax
        shr     $3, %eax
        jz      .Ldo_dword
 .Ldo_qwords:
-       crc32q  (bufptmp), crc_init
+       crc32q  (bufptmp), crc_init_q
        add     $8, bufptmp
        dec     %eax
        jnz     .Ldo_qwords
 .Ldo_dword:
-       test    $4, len_dw
+       test    $4, len
        jz      .Ldo_word
-       crc32l  (bufptmp), crc_init_dw
+       crc32l  (bufptmp), crc_init
        add     $4, bufptmp
 .Ldo_word:
-       test    $2, len_dw
+       test    $2, len
        jz      .Ldo_byte
-       crc32w  (bufptmp), crc_init_dw
+       crc32w  (bufptmp), crc_init
        add     $2, bufptmp
 .Ldo_byte:
-       test    $1, len_dw
+       test    $1, len
        jz      .Ldone
-       crc32b  (bufptmp), crc_init_dw
+       crc32b  (bufptmp), crc_init
 .Ldone:
-       movq    crc_init, %rax
+       mov     crc_init, %eax
        popq    %rsi
        popq    %rdi
        popq    %rbx