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Date: Fri, 24 Jul 2020 02:25:42 +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 16/20] mips: propagate the calling convention change down into __csum_partial_copy_..._user()
From: Al Viro <viro@...iv.linux.org.uk>
and turn the exception handlers into simply returning 0, which
simplifies the hell out of things in csum_partial.S
Signed-off-by: Al Viro <viro@...iv.linux.org.uk>
---
arch/mips/include/asm/checksum.h | 26 +---
arch/mips/lib/csum_partial.S | 258 +++++++++++++--------------------------
2 files changed, 89 insertions(+), 195 deletions(-)
diff --git a/arch/mips/include/asm/checksum.h b/arch/mips/include/asm/checksum.h
index a8ff9c306363..c6c682519d94 100644
--- a/arch/mips/include/asm/checksum.h
+++ b/arch/mips/include/asm/checksum.h
@@ -34,25 +34,17 @@
*/
__wsum csum_partial(const void *buff, int len, __wsum sum);
-__wsum __csum_partial_copy_from_user(const void *src, void *dst,
- int len, __wsum sum, int *err_ptr);
-__wsum __csum_partial_copy_to_user(const void *src, void *dst,
- int len, __wsum sum, int *err_ptr);
+__wsum __csum_partial_copy_from_user(const void __user *src, void *dst, int len);
+__wsum __csum_partial_copy_to_user(const void *src, void __user *dst, int len);
#define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
static inline
__wsum csum_and_copy_from_user(const void __user *src, void *dst, int len)
{
- __wsum sum = ~0U;
- int err = 0;
-
might_fault();
-
if (!access_ok(src, len))
return 0;
- sum = __csum_partial_copy_from_user((__force void *)src, dst,
- len, sum, &err);
- return err ? 0 : sum;
+ return __csum_partial_copy_from_user(src, dst, len);
}
/*
@@ -62,16 +54,10 @@ __wsum csum_and_copy_from_user(const void __user *src, void *dst, int len)
static inline
__wsum csum_and_copy_to_user(const void *src, void __user *dst, int len)
{
- int err = 0;
- __wsum sum = ~0U;
-
might_fault();
if (!access_ok(dst, len))
return 0;
- sum = __csum_partial_copy_to_user(src,
- (__force void *)dst,
- len, sum, &err);
- return err ? 0 : sum;
+ return __csum_partial_copy_to_user(src, dst, len);
}
/*
@@ -79,10 +65,10 @@ __wsum csum_and_copy_to_user(const void *src, void __user *dst, int len)
* we have just one address space, so this is identical to the above)
*/
#define _HAVE_ARCH_CSUM_AND_COPY
-__wsum __csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum);
+__wsum __csum_partial_copy_nocheck(const void *src, void *dst, int len);
static inline __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len)
{
- return __csum_partial_copy_nocheck(src, dst, len, 0);
+ return __csum_partial_copy_nocheck(src, dst, len);
}
/*
diff --git a/arch/mips/lib/csum_partial.S b/arch/mips/lib/csum_partial.S
index 983e909c2052..a46db0807195 100644
--- a/arch/mips/lib/csum_partial.S
+++ b/arch/mips/lib/csum_partial.S
@@ -308,8 +308,8 @@ EXPORT_SYMBOL(csum_partial)
/*
* checksum and copy routines based on memcpy.S
*
- * csum_partial_copy_nocheck(src, dst, len, sum)
- * __csum_partial_copy_kernel(src, dst, len, sum, errp)
+ * csum_partial_copy_nocheck(src, dst, len)
+ * __csum_partial_copy_kernel(src, dst, len)
*
* See "Spec" in memcpy.S for details. Unlike __copy_user, all
* function in this file use the standard calling convention.
@@ -318,26 +318,11 @@ EXPORT_SYMBOL(csum_partial)
#define src a0
#define dst a1
#define len a2
-#define psum a3
#define sum v0
#define odd t8
-#define errptr t9
/*
- * The exception handler for loads requires that:
- * 1- AT contain the address of the byte just past the end of the source
- * of the copy,
- * 2- src_entry <= src < AT, and
- * 3- (dst - src) == (dst_entry - src_entry),
- * The _entry suffix denotes values when __copy_user was called.
- *
- * (1) is set up up by __csum_partial_copy_from_user and maintained by
- * not writing AT in __csum_partial_copy
- * (2) is met by incrementing src by the number of bytes copied
- * (3) is met by not doing loads between a pair of increments of dst and src
- *
- * The exception handlers for stores stores -EFAULT to errptr and return.
- * These handlers do not need to overwrite any data.
+ * All exception handlers simply return 0.
*/
/* Instruction type */
@@ -358,11 +343,11 @@ EXPORT_SYMBOL(csum_partial)
* addr : Address
* handler : Exception handler
*/
-#define EXC(insn, type, reg, addr, handler) \
+#define EXC(insn, type, reg, addr) \
.if \mode == LEGACY_MODE; \
9: insn reg, addr; \
.section __ex_table,"a"; \
- PTR 9b, handler; \
+ PTR 9b, .L_exc; \
.previous; \
/* This is enabled in EVA mode */ \
.else; \
@@ -371,7 +356,7 @@ EXPORT_SYMBOL(csum_partial)
((\to == USEROP) && (type == ST_INSN)); \
9: __BUILD_EVA_INSN(insn##e, reg, addr); \
.section __ex_table,"a"; \
- PTR 9b, handler; \
+ PTR 9b, .L_exc; \
.previous; \
.else; \
/* EVA without exception */ \
@@ -384,14 +369,14 @@ EXPORT_SYMBOL(csum_partial)
#ifdef USE_DOUBLE
#define LOADK ld /* No exception */
-#define LOAD(reg, addr, handler) EXC(ld, LD_INSN, reg, addr, handler)
-#define LOADBU(reg, addr, handler) EXC(lbu, LD_INSN, reg, addr, handler)
-#define LOADL(reg, addr, handler) EXC(ldl, LD_INSN, reg, addr, handler)
-#define LOADR(reg, addr, handler) EXC(ldr, LD_INSN, reg, addr, handler)
-#define STOREB(reg, addr, handler) EXC(sb, ST_INSN, reg, addr, handler)
-#define STOREL(reg, addr, handler) EXC(sdl, ST_INSN, reg, addr, handler)
-#define STORER(reg, addr, handler) EXC(sdr, ST_INSN, reg, addr, handler)
-#define STORE(reg, addr, handler) EXC(sd, ST_INSN, reg, addr, handler)
+#define LOAD(reg, addr) EXC(ld, LD_INSN, reg, addr)
+#define LOADBU(reg, addr) EXC(lbu, LD_INSN, reg, addr)
+#define LOADL(reg, addr) EXC(ldl, LD_INSN, reg, addr)
+#define LOADR(reg, addr) EXC(ldr, LD_INSN, reg, addr)
+#define STOREB(reg, addr) EXC(sb, ST_INSN, reg, addr)
+#define STOREL(reg, addr) EXC(sdl, ST_INSN, reg, addr)
+#define STORER(reg, addr) EXC(sdr, ST_INSN, reg, addr)
+#define STORE(reg, addr) EXC(sd, ST_INSN, reg, addr)
#define ADD daddu
#define SUB dsubu
#define SRL dsrl
@@ -404,14 +389,14 @@ EXPORT_SYMBOL(csum_partial)
#else
#define LOADK lw /* No exception */
-#define LOAD(reg, addr, handler) EXC(lw, LD_INSN, reg, addr, handler)
-#define LOADBU(reg, addr, handler) EXC(lbu, LD_INSN, reg, addr, handler)
-#define LOADL(reg, addr, handler) EXC(lwl, LD_INSN, reg, addr, handler)
-#define LOADR(reg, addr, handler) EXC(lwr, LD_INSN, reg, addr, handler)
-#define STOREB(reg, addr, handler) EXC(sb, ST_INSN, reg, addr, handler)
-#define STOREL(reg, addr, handler) EXC(swl, ST_INSN, reg, addr, handler)
-#define STORER(reg, addr, handler) EXC(swr, ST_INSN, reg, addr, handler)
-#define STORE(reg, addr, handler) EXC(sw, ST_INSN, reg, addr, handler)
+#define LOAD(reg, addr) EXC(lw, LD_INSN, reg, addr)
+#define LOADBU(reg, addr) EXC(lbu, LD_INSN, reg, addr)
+#define LOADL(reg, addr) EXC(lwl, LD_INSN, reg, addr)
+#define LOADR(reg, addr) EXC(lwr, LD_INSN, reg, addr)
+#define STOREB(reg, addr) EXC(sb, ST_INSN, reg, addr)
+#define STOREL(reg, addr) EXC(swl, ST_INSN, reg, addr)
+#define STORER(reg, addr) EXC(swr, ST_INSN, reg, addr)
+#define STORE(reg, addr) EXC(sw, ST_INSN, reg, addr)
#define ADD addu
#define SUB subu
#define SRL srl
@@ -450,22 +435,9 @@ EXPORT_SYMBOL(csum_partial)
.set at=v1
#endif
- .macro __BUILD_CSUM_PARTIAL_COPY_USER mode, from, to, __nocheck
+ .macro __BUILD_CSUM_PARTIAL_COPY_USER mode, from, to
- PTR_ADDU AT, src, len /* See (1) above. */
- /* initialize __nocheck if this the first time we execute this
- * macro
- */
-#ifdef CONFIG_64BIT
- move errptr, a4
-#else
- lw errptr, 16(sp)
-#endif
- .if \__nocheck == 1
- FEXPORT(__csum_partial_copy_nocheck)
- EXPORT_SYMBOL(__csum_partial_copy_nocheck)
- .endif
- move sum, zero
+ li sum, -1
move odd, zero
/*
* Note: dst & src may be unaligned, len may be 0
@@ -497,31 +469,31 @@ EXPORT_SYMBOL(csum_partial)
SUB len, 8*NBYTES # subtract here for bgez loop
.align 4
1:
- LOAD(t0, UNIT(0)(src), .Ll_exc\@)
- LOAD(t1, UNIT(1)(src), .Ll_exc_copy\@)
- LOAD(t2, UNIT(2)(src), .Ll_exc_copy\@)
- LOAD(t3, UNIT(3)(src), .Ll_exc_copy\@)
- LOAD(t4, UNIT(4)(src), .Ll_exc_copy\@)
- LOAD(t5, UNIT(5)(src), .Ll_exc_copy\@)
- LOAD(t6, UNIT(6)(src), .Ll_exc_copy\@)
- LOAD(t7, UNIT(7)(src), .Ll_exc_copy\@)
+ LOAD(t0, UNIT(0)(src))
+ LOAD(t1, UNIT(1)(src))
+ LOAD(t2, UNIT(2)(src))
+ LOAD(t3, UNIT(3)(src))
+ LOAD(t4, UNIT(4)(src))
+ LOAD(t5, UNIT(5)(src))
+ LOAD(t6, UNIT(6)(src))
+ LOAD(t7, UNIT(7)(src))
SUB len, len, 8*NBYTES
ADD src, src, 8*NBYTES
- STORE(t0, UNIT(0)(dst), .Ls_exc\@)
+ STORE(t0, UNIT(0)(dst))
ADDC(t0, t1)
- STORE(t1, UNIT(1)(dst), .Ls_exc\@)
+ STORE(t1, UNIT(1)(dst))
ADDC(sum, t0)
- STORE(t2, UNIT(2)(dst), .Ls_exc\@)
+ STORE(t2, UNIT(2)(dst))
ADDC(t2, t3)
- STORE(t3, UNIT(3)(dst), .Ls_exc\@)
+ STORE(t3, UNIT(3)(dst))
ADDC(sum, t2)
- STORE(t4, UNIT(4)(dst), .Ls_exc\@)
+ STORE(t4, UNIT(4)(dst))
ADDC(t4, t5)
- STORE(t5, UNIT(5)(dst), .Ls_exc\@)
+ STORE(t5, UNIT(5)(dst))
ADDC(sum, t4)
- STORE(t6, UNIT(6)(dst), .Ls_exc\@)
+ STORE(t6, UNIT(6)(dst))
ADDC(t6, t7)
- STORE(t7, UNIT(7)(dst), .Ls_exc\@)
+ STORE(t7, UNIT(7)(dst))
ADDC(sum, t6)
.set reorder /* DADDI_WAR */
ADD dst, dst, 8*NBYTES
@@ -541,19 +513,19 @@ EXPORT_SYMBOL(csum_partial)
/*
* len >= 4*NBYTES
*/
- LOAD(t0, UNIT(0)(src), .Ll_exc\@)
- LOAD(t1, UNIT(1)(src), .Ll_exc_copy\@)
- LOAD(t2, UNIT(2)(src), .Ll_exc_copy\@)
- LOAD(t3, UNIT(3)(src), .Ll_exc_copy\@)
+ LOAD(t0, UNIT(0)(src))
+ LOAD(t1, UNIT(1)(src))
+ LOAD(t2, UNIT(2)(src))
+ LOAD(t3, UNIT(3)(src))
SUB len, len, 4*NBYTES
ADD src, src, 4*NBYTES
- STORE(t0, UNIT(0)(dst), .Ls_exc\@)
+ STORE(t0, UNIT(0)(dst))
ADDC(t0, t1)
- STORE(t1, UNIT(1)(dst), .Ls_exc\@)
+ STORE(t1, UNIT(1)(dst))
ADDC(sum, t0)
- STORE(t2, UNIT(2)(dst), .Ls_exc\@)
+ STORE(t2, UNIT(2)(dst))
ADDC(t2, t3)
- STORE(t3, UNIT(3)(dst), .Ls_exc\@)
+ STORE(t3, UNIT(3)(dst))
ADDC(sum, t2)
.set reorder /* DADDI_WAR */
ADD dst, dst, 4*NBYTES
@@ -566,10 +538,10 @@ EXPORT_SYMBOL(csum_partial)
beq rem, len, .Lcopy_bytes\@
nop
1:
- LOAD(t0, 0(src), .Ll_exc\@)
+ LOAD(t0, 0(src))
ADD src, src, NBYTES
SUB len, len, NBYTES
- STORE(t0, 0(dst), .Ls_exc\@)
+ STORE(t0, 0(dst))
ADDC(sum, t0)
.set reorder /* DADDI_WAR */
ADD dst, dst, NBYTES
@@ -592,10 +564,10 @@ EXPORT_SYMBOL(csum_partial)
ADD t1, dst, len # t1 is just past last byte of dst
li bits, 8*NBYTES
SLL rem, len, 3 # rem = number of bits to keep
- LOAD(t0, 0(src), .Ll_exc\@)
+ LOAD(t0, 0(src))
SUB bits, bits, rem # bits = number of bits to discard
SHIFT_DISCARD t0, t0, bits
- STREST(t0, -1(t1), .Ls_exc\@)
+ STREST(t0, -1(t1))
SHIFT_DISCARD_REVERT t0, t0, bits
.set reorder
ADDC(sum, t0)
@@ -612,12 +584,12 @@ EXPORT_SYMBOL(csum_partial)
* Set match = (src and dst have same alignment)
*/
#define match rem
- LDFIRST(t3, FIRST(0)(src), .Ll_exc\@)
+ LDFIRST(t3, FIRST(0)(src))
ADD t2, zero, NBYTES
- LDREST(t3, REST(0)(src), .Ll_exc_copy\@)
+ LDREST(t3, REST(0)(src))
SUB t2, t2, t1 # t2 = number of bytes copied
xor match, t0, t1
- STFIRST(t3, FIRST(0)(dst), .Ls_exc\@)
+ STFIRST(t3, FIRST(0)(dst))
SLL t4, t1, 3 # t4 = number of bits to discard
SHIFT_DISCARD t3, t3, t4
/* no SHIFT_DISCARD_REVERT to handle odd buffer properly */
@@ -639,26 +611,26 @@ EXPORT_SYMBOL(csum_partial)
* It's OK to load FIRST(N+1) before REST(N) because the two addresses
* are to the same unit (unless src is aligned, but it's not).
*/
- LDFIRST(t0, FIRST(0)(src), .Ll_exc\@)
- LDFIRST(t1, FIRST(1)(src), .Ll_exc_copy\@)
+ LDFIRST(t0, FIRST(0)(src))
+ LDFIRST(t1, FIRST(1)(src))
SUB len, len, 4*NBYTES
- LDREST(t0, REST(0)(src), .Ll_exc_copy\@)
- LDREST(t1, REST(1)(src), .Ll_exc_copy\@)
- LDFIRST(t2, FIRST(2)(src), .Ll_exc_copy\@)
- LDFIRST(t3, FIRST(3)(src), .Ll_exc_copy\@)
- LDREST(t2, REST(2)(src), .Ll_exc_copy\@)
- LDREST(t3, REST(3)(src), .Ll_exc_copy\@)
+ LDREST(t0, REST(0)(src))
+ LDREST(t1, REST(1)(src))
+ LDFIRST(t2, FIRST(2)(src))
+ LDFIRST(t3, FIRST(3)(src))
+ LDREST(t2, REST(2)(src))
+ LDREST(t3, REST(3)(src))
ADD src, src, 4*NBYTES
#ifdef CONFIG_CPU_SB1
nop # improves slotting
#endif
- STORE(t0, UNIT(0)(dst), .Ls_exc\@)
+ STORE(t0, UNIT(0)(dst))
ADDC(t0, t1)
- STORE(t1, UNIT(1)(dst), .Ls_exc\@)
+ STORE(t1, UNIT(1)(dst))
ADDC(sum, t0)
- STORE(t2, UNIT(2)(dst), .Ls_exc\@)
+ STORE(t2, UNIT(2)(dst))
ADDC(t2, t3)
- STORE(t3, UNIT(3)(dst), .Ls_exc\@)
+ STORE(t3, UNIT(3)(dst))
ADDC(sum, t2)
.set reorder /* DADDI_WAR */
ADD dst, dst, 4*NBYTES
@@ -671,11 +643,11 @@ EXPORT_SYMBOL(csum_partial)
beq rem, len, .Lcopy_bytes\@
nop
1:
- LDFIRST(t0, FIRST(0)(src), .Ll_exc\@)
- LDREST(t0, REST(0)(src), .Ll_exc_copy\@)
+ LDFIRST(t0, FIRST(0)(src))
+ LDREST(t0, REST(0)(src))
ADD src, src, NBYTES
SUB len, len, NBYTES
- STORE(t0, 0(dst), .Ls_exc\@)
+ STORE(t0, 0(dst))
ADDC(sum, t0)
.set reorder /* DADDI_WAR */
ADD dst, dst, NBYTES
@@ -696,11 +668,10 @@ EXPORT_SYMBOL(csum_partial)
#endif
move t2, zero # partial word
li t3, SHIFT_START # shift
-/* use .Ll_exc_copy here to return correct sum on fault */
#define COPY_BYTE(N) \
- LOADBU(t0, N(src), .Ll_exc_copy\@); \
+ LOADBU(t0, N(src)); \
SUB len, len, 1; \
- STOREB(t0, N(dst), .Ls_exc\@); \
+ STOREB(t0, N(dst)); \
SLLV t0, t0, t3; \
addu t3, SHIFT_INC; \
beqz len, .Lcopy_bytes_done\@; \
@@ -714,9 +685,9 @@ EXPORT_SYMBOL(csum_partial)
COPY_BYTE(4)
COPY_BYTE(5)
#endif
- LOADBU(t0, NBYTES-2(src), .Ll_exc_copy\@)
+ LOADBU(t0, NBYTES-2(src))
SUB len, len, 1
- STOREB(t0, NBYTES-2(dst), .Ls_exc\@)
+ STOREB(t0, NBYTES-2(dst))
SLLV t0, t0, t3
or t2, t0
.Lcopy_bytes_done\@:
@@ -753,94 +724,31 @@ EXPORT_SYMBOL(csum_partial)
#endif
.set pop
.set reorder
- ADDC32(sum, psum)
jr ra
.set noreorder
+ .endm
-.Ll_exc_copy\@:
- /*
- * Copy bytes from src until faulting load address (or until a
- * lb faults)
- *
- * When reached by a faulting LDFIRST/LDREST, THREAD_BUADDR($28)
- * may be more than a byte beyond the last address.
- * Hence, the lb below may get an exception.
- *
- * Assumes src < THREAD_BUADDR($28)
- */
- LOADK t0, TI_TASK($28)
- li t2, SHIFT_START
- LOADK t0, THREAD_BUADDR(t0)
-1:
- LOADBU(t1, 0(src), .Ll_exc\@)
- ADD src, src, 1
- sb t1, 0(dst) # can't fault -- we're copy_from_user
- SLLV t1, t1, t2
- addu t2, SHIFT_INC
- ADDC(sum, t1)
- .set reorder /* DADDI_WAR */
- ADD dst, dst, 1
- bne src, t0, 1b
- .set noreorder
-.Ll_exc\@:
- LOADK t0, TI_TASK($28)
- nop
- LOADK t0, THREAD_BUADDR(t0) # t0 is just past last good address
- nop
- SUB len, AT, t0 # len number of uncopied bytes
- /*
- * Here's where we rely on src and dst being incremented in tandem,
- * See (3) above.
- * dst += (fault addr - src) to put dst at first byte to clear
- */
- ADD dst, t0 # compute start address in a1
- SUB dst, src
- /*
- * Clear len bytes starting at dst. Can't call __bzero because it
- * might modify len. An inefficient loop for these rare times...
- */
- .set reorder /* DADDI_WAR */
- SUB src, len, 1
- beqz len, .Ldone\@
- .set noreorder
-1: sb zero, 0(dst)
- ADD dst, dst, 1
- .set push
- .set noat
-#ifndef CONFIG_CPU_DADDI_WORKAROUNDS
- bnez src, 1b
- SUB src, src, 1
-#else
- li v1, 1
- bnez src, 1b
- SUB src, src, v1
-#endif
- li v1, -EFAULT
- b .Ldone\@
- sw v1, (errptr)
-
-.Ls_exc\@:
- li v0, -1 /* invalid checksum */
- li v1, -EFAULT
+ .set noreorder
+.L_exc:
jr ra
- sw v1, (errptr)
- .set pop
- .endm
+ li v0, 0
+FEXPORT(__csum_partial_copy_nocheck)
+EXPORT_SYMBOL(__csum_partial_copy_nocheck)
#ifndef CONFIG_EVA
FEXPORT(__csum_partial_copy_to_user)
EXPORT_SYMBOL(__csum_partial_copy_to_user)
FEXPORT(__csum_partial_copy_from_user)
EXPORT_SYMBOL(__csum_partial_copy_from_user)
#endif
-__BUILD_CSUM_PARTIAL_COPY_USER LEGACY_MODE USEROP USEROP 1
+__BUILD_CSUM_PARTIAL_COPY_USER LEGACY_MODE USEROP USEROP
#ifdef CONFIG_EVA
LEAF(__csum_partial_copy_to_user)
-__BUILD_CSUM_PARTIAL_COPY_USER EVA_MODE KERNELOP USEROP 0
+__BUILD_CSUM_PARTIAL_COPY_USER EVA_MODE KERNELOP USEROP
END(__csum_partial_copy_to_user)
LEAF(__csum_partial_copy_from_user)
-__BUILD_CSUM_PARTIAL_COPY_USER EVA_MODE USEROP KERNELOP 0
+__BUILD_CSUM_PARTIAL_COPY_USER EVA_MODE USEROP KERNELOP
END(__csum_partial_copy_from_user)
#endif
--
2.11.0
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