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Message-Id: <20200724012546.302155-12-viro@ZenIV.linux.org.uk>
Date: Fri, 24 Jul 2020 02:25:38 +0100
From: Al Viro <viro@...IV.linux.org.uk>
To: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: linux-kernel@...r.kernel.org, linux-arch@...r.kernel.org
Subject: [PATCH v2 12/20] i386: propagate the calling conventions change down to csum_partial_copy_generic()
From: Al Viro <viro@...iv.linux.org.uk>
... and don't bother zeroing destination on error
Signed-off-by: Al Viro <viro@...iv.linux.org.uk>
---
arch/x86/include/asm/checksum_32.h | 18 ++----
arch/x86/lib/checksum_32.S | 117 +++++++++++++------------------------
2 files changed, 47 insertions(+), 88 deletions(-)
diff --git a/arch/x86/include/asm/checksum_32.h b/arch/x86/include/asm/checksum_32.h
index 5948cde9e4ad..17da95387997 100644
--- a/arch/x86/include/asm/checksum_32.h
+++ b/arch/x86/include/asm/checksum_32.h
@@ -27,9 +27,7 @@ asmlinkage __wsum csum_partial(const void *buff, int len, __wsum sum);
* better 64-bit) boundary
*/
-asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst,
- int len, __wsum sum,
- int *src_err_ptr, int *dst_err_ptr);
+asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst, int len);
/*
* Note: when you get a NULL pointer exception here this means someone
@@ -40,23 +38,21 @@ asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst,
*/
static inline __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len)
{
- return csum_partial_copy_generic(src, dst, len, 0, NULL, NULL);
+ return csum_partial_copy_generic(src, dst, len);
}
static inline __wsum csum_and_copy_from_user(const void __user *src,
void *dst, int len)
{
__wsum ret;
- int err = 0;
might_sleep();
if (!user_access_begin(src, len))
return 0;
- ret = csum_partial_copy_generic((__force void *)src, dst,
- len, ~0U, &err, NULL);
+ ret = csum_partial_copy_generic((__force void *)src, dst, len);
user_access_end();
- return err ? 0 : ret;
+ return ret;
}
/*
@@ -177,16 +173,14 @@ static inline __wsum csum_and_copy_to_user(const void *src,
int len)
{
__wsum ret;
- int err = 0;
might_sleep();
if (!user_access_begin(dst, len))
return 0;
- ret = csum_partial_copy_generic(src, (__force void *)dst,
- len, ~0U, NULL, &err);
+ ret = csum_partial_copy_generic(src, (__force void *)dst, len);
user_access_end();
- return err ? 0 : ret;
+ return ret;
}
#endif /* _ASM_X86_CHECKSUM_32_H */
diff --git a/arch/x86/lib/checksum_32.S b/arch/x86/lib/checksum_32.S
index d1d768912368..4304320e51f4 100644
--- a/arch/x86/lib/checksum_32.S
+++ b/arch/x86/lib/checksum_32.S
@@ -253,28 +253,17 @@ EXPORT_SYMBOL(csum_partial)
/*
unsigned int csum_partial_copy_generic (const char *src, char *dst,
- int len, int sum, int *src_err_ptr, int *dst_err_ptr)
+ int len)
*/
/*
* Copy from ds while checksumming, otherwise like csum_partial
- *
- * The macros SRC and DST specify the type of access for the instruction.
- * thus we can call a custom exception handler for all access types.
- *
- * FIXME: could someone double-check whether I haven't mixed up some SRC and
- * DST definitions? It's damn hard to trigger all cases. I hope I got
- * them all but there's no guarantee.
*/
-#define SRC(y...) \
+#define EXC(y...) \
9999: y; \
_ASM_EXTABLE_UA(9999b, 6001f)
-#define DST(y...) \
- 9999: y; \
- _ASM_EXTABLE_UA(9999b, 6002f)
-
#ifndef CONFIG_X86_USE_PPRO_CHECKSUM
#define ARGBASE 16
@@ -285,20 +274,20 @@ SYM_FUNC_START(csum_partial_copy_generic)
pushl %edi
pushl %esi
pushl %ebx
- movl ARGBASE+16(%esp),%eax # sum
movl ARGBASE+12(%esp),%ecx # len
movl ARGBASE+4(%esp),%esi # src
movl ARGBASE+8(%esp),%edi # dst
+ movl $-1, %eax # sum
testl $2, %edi # Check alignment.
jz 2f # Jump if alignment is ok.
subl $2, %ecx # Alignment uses up two bytes.
jae 1f # Jump if we had at least two bytes.
addl $2, %ecx # ecx was < 2. Deal with it.
jmp 4f
-SRC(1: movw (%esi), %bx )
+EXC(1: movw (%esi), %bx )
addl $2, %esi
-DST( movw %bx, (%edi) )
+EXC( movw %bx, (%edi) )
addl $2, %edi
addw %bx, %ax
adcl $0, %eax
@@ -306,34 +295,34 @@ DST( movw %bx, (%edi) )
movl %ecx, FP(%esp)
shrl $5, %ecx
jz 2f
- testl %esi, %esi
-SRC(1: movl (%esi), %ebx )
-SRC( movl 4(%esi), %edx )
+ testl %esi, %esi # what's wrong with clc?
+EXC(1: movl (%esi), %ebx )
+EXC( movl 4(%esi), %edx )
adcl %ebx, %eax
-DST( movl %ebx, (%edi) )
+EXC( movl %ebx, (%edi) )
adcl %edx, %eax
-DST( movl %edx, 4(%edi) )
+EXC( movl %edx, 4(%edi) )
-SRC( movl 8(%esi), %ebx )
-SRC( movl 12(%esi), %edx )
+EXC( movl 8(%esi), %ebx )
+EXC( movl 12(%esi), %edx )
adcl %ebx, %eax
-DST( movl %ebx, 8(%edi) )
+EXC( movl %ebx, 8(%edi) )
adcl %edx, %eax
-DST( movl %edx, 12(%edi) )
+EXC( movl %edx, 12(%edi) )
-SRC( movl 16(%esi), %ebx )
-SRC( movl 20(%esi), %edx )
+EXC( movl 16(%esi), %ebx )
+EXC( movl 20(%esi), %edx )
adcl %ebx, %eax
-DST( movl %ebx, 16(%edi) )
+EXC( movl %ebx, 16(%edi) )
adcl %edx, %eax
-DST( movl %edx, 20(%edi) )
+EXC( movl %edx, 20(%edi) )
-SRC( movl 24(%esi), %ebx )
-SRC( movl 28(%esi), %edx )
+EXC( movl 24(%esi), %ebx )
+EXC( movl 28(%esi), %edx )
adcl %ebx, %eax
-DST( movl %ebx, 24(%edi) )
+EXC( movl %ebx, 24(%edi) )
adcl %edx, %eax
-DST( movl %edx, 28(%edi) )
+EXC( movl %edx, 28(%edi) )
lea 32(%esi), %esi
lea 32(%edi), %edi
@@ -345,9 +334,9 @@ DST( movl %edx, 28(%edi) )
andl $0x1c, %edx
je 4f
shrl $2, %edx # This clears CF
-SRC(3: movl (%esi), %ebx )
+EXC(3: movl (%esi), %ebx )
adcl %ebx, %eax
-DST( movl %ebx, (%edi) )
+EXC( movl %ebx, (%edi) )
lea 4(%esi), %esi
lea 4(%edi), %edi
dec %edx
@@ -357,39 +346,24 @@ DST( movl %ebx, (%edi) )
jz 7f
cmpl $2, %ecx
jb 5f
-SRC( movw (%esi), %cx )
+EXC( movw (%esi), %cx )
leal 2(%esi), %esi
-DST( movw %cx, (%edi) )
+EXC( movw %cx, (%edi) )
leal 2(%edi), %edi
je 6f
shll $16,%ecx
-SRC(5: movb (%esi), %cl )
-DST( movb %cl, (%edi) )
+EXC(5: movb (%esi), %cl )
+EXC( movb %cl, (%edi) )
6: addl %ecx, %eax
adcl $0, %eax
7:
-5000:
# Exception handler:
.section .fixup, "ax"
6001:
- movl ARGBASE+20(%esp), %ebx # src_err_ptr
- movl $-EFAULT, (%ebx)
-
- # zero the complete destination - computing the rest
- # is too much work
- movl ARGBASE+8(%esp), %edi # dst
- movl ARGBASE+12(%esp), %ecx # len
- xorl %eax,%eax
- rep ; stosb
-
- jmp 5000b
-
-6002:
- movl ARGBASE+24(%esp), %ebx # dst_err_ptr
- movl $-EFAULT,(%ebx)
- jmp 5000b
+ xorl %eax, %eax
+ jmp 7b
.previous
@@ -405,14 +379,14 @@ SYM_FUNC_END(csum_partial_copy_generic)
/* Version for PentiumII/PPro */
#define ROUND1(x) \
- SRC(movl x(%esi), %ebx ) ; \
+ EXC(movl x(%esi), %ebx ) ; \
addl %ebx, %eax ; \
- DST(movl %ebx, x(%edi) ) ;
+ EXC(movl %ebx, x(%edi) ) ;
#define ROUND(x) \
- SRC(movl x(%esi), %ebx ) ; \
+ EXC(movl x(%esi), %ebx ) ; \
adcl %ebx, %eax ; \
- DST(movl %ebx, x(%edi) ) ;
+ EXC(movl %ebx, x(%edi) ) ;
#define ARGBASE 12
@@ -423,7 +397,7 @@ SYM_FUNC_START(csum_partial_copy_generic)
movl ARGBASE+4(%esp),%esi #src
movl ARGBASE+8(%esp),%edi #dst
movl ARGBASE+12(%esp),%ecx #len
- movl ARGBASE+16(%esp),%eax #sum
+ movl $-1, %eax #sum
# movl %ecx, %edx
movl %ecx, %ebx
movl %esi, %edx
@@ -439,7 +413,7 @@ SYM_FUNC_START(csum_partial_copy_generic)
JMP_NOSPEC ebx
1: addl $64,%esi
addl $64,%edi
- SRC(movb -32(%edx),%bl) ; SRC(movb (%edx),%bl)
+ EXC(movb -32(%edx),%bl) ; EXC(movb (%edx),%bl)
ROUND1(-64) ROUND(-60) ROUND(-56) ROUND(-52)
ROUND (-48) ROUND(-44) ROUND(-40) ROUND(-36)
ROUND (-32) ROUND(-28) ROUND(-24) ROUND(-20)
@@ -453,29 +427,20 @@ SYM_FUNC_START(csum_partial_copy_generic)
jz 7f
cmpl $2, %edx
jb 5f
-SRC( movw (%esi), %dx )
+EXC( movw (%esi), %dx )
leal 2(%esi), %esi
-DST( movw %dx, (%edi) )
+EXC( movw %dx, (%edi) )
leal 2(%edi), %edi
je 6f
shll $16,%edx
5:
-SRC( movb (%esi), %dl )
-DST( movb %dl, (%edi) )
+EXC( movb (%esi), %dl )
+EXC( movb %dl, (%edi) )
6: addl %edx, %eax
adcl $0, %eax
7:
.section .fixup, "ax"
-6001: movl ARGBASE+20(%esp), %ebx # src_err_ptr
- movl $-EFAULT, (%ebx)
- # zero the complete destination (computing the rest is too much work)
- movl ARGBASE+8(%esp),%edi # dst
- movl ARGBASE+12(%esp),%ecx # len
- xorl %eax,%eax
- rep; stosb
- jmp 7b
-6002: movl ARGBASE+24(%esp), %ebx # dst_err_ptr
- movl $-EFAULT, (%ebx)
+6001: xorl %eax, %eax
jmp 7b
.previous
--
2.11.0
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