From: Randolph Chung <randolph@tausq.org>
To: PARISC list <parisc-linux@lists.parisc-linux.org>
Subject: Re: [parisc-linux] [RFC] Revamp exception handling in the kernel
Date: Mon, 13 Sep 2004 16:37:42 -0700 [thread overview]
Message-ID: <20040913233742.GW28659@tausq.org> (raw)
In-Reply-To: <20040911165325.GO28659@tausq.org>
Version 2 of the patch. Changes from the previous version:
- Uses centralized exception handling for get_user/put_user
- Uses per-cpu variables to store the fault ip, fault space and fault
address (not controlled by a flag)
- 64-bit get_user/put_user for 32-bit kernels is a bit broken in the old
code. this contains a fix for that as well.
Tested against 2.6.8.1-pa11 for 64-UP and 64-SMP
jejb asked me why we don't do the fixup in C code. It seems to me that
in order to do that, we will need to mark all the caller-saved registers
as clobbered by get_user/put_user. That may cause a large amount of
register spills across those calls, even for non-faulting cases.
But the alternative (as implemented below) is some rather nasty-looking
asm code in the fixup handler. A third alternative might be for the
fixup handler to create a stack frame and save/restore caller-saved
registers across a call to a C-code handler. seems like a lot of
work....
Thoughts?
randolph
Index: arch/parisc/kernel/asm-offsets.c
===================================================================
RCS file: /var/cvs/linux-2.6/arch/parisc/kernel/asm-offsets.c,v
retrieving revision 1.9
diff -u -p -r1.9 asm-offsets.c
--- arch/parisc/kernel/asm-offsets.c 8 May 2004 14:12:45 -0000 1.9
+++ arch/parisc/kernel/asm-offsets.c 13 Sep 2004 23:31:46 -0000
@@ -38,6 +38,7 @@
#include <asm/processor.h>
#include <asm/hardirq.h>
#include <asm/pdc.h>
+#include <asm/uaccess.h>
#define DEFINE(sym, val) \
asm volatile("\n->" #sym " %0 " #val : : "i" (val))
@@ -291,5 +292,8 @@ int main(void)
DEFINE(ASM_PT_INITIAL, PT_INITIAL);
DEFINE(ASM_PAGE_SIZE, PAGE_SIZE);
BLANK();
+ DEFINE(EXCDATA_IP, offsetof(struct exception_data, fault_ip));
+ DEFINE(EXCDATA_SPACE, offsetof(struct exception_data, fault_space));
+ DEFINE(EXCDATA_ADDR, offsetof(struct exception_data, fault_addr));
return 0;
}
Index: arch/parisc/kernel/syscall.S
===================================================================
RCS file: /var/cvs/linux-2.6/arch/parisc/kernel/syscall.S,v
retrieving revision 1.14
diff -u -p -r1.14 syscall.S
--- arch/parisc/kernel/syscall.S 10 Sep 2004 14:52:01 -0000 1.14
+++ arch/parisc/kernel/syscall.S 13 Sep 2004 23:31:46 -0000
@@ -29,6 +29,19 @@
#else
.level 1.1
#endif
+
+#ifndef __LP64__
+ .macro fixup_branch,lbl
+ b \lbl
+ .endm
+#else
+ .macro fixup_branch,lbl
+ ldil L%\lbl, %r1
+ ldo R%\lbl(%r1), %r1
+ bv,n %r0(%r1)
+ .endm
+#endif
+
.text
.import syscall_exit,code
@@ -575,10 +588,8 @@ cas_action:
/* Return to userspace, set no error */
b lws_exit
copy %r0, %r21
- nop /* Add some visual space in objdump */
- nop
- nop
- nop
+
+ .section .fixup,"ax"
3:
/* Error occured on load or store */
#ifdef CONFIG_SMP
@@ -588,12 +599,13 @@ cas_action:
stw %r0, 4(%sr2,%r20)
# endif
#endif
- b lws_exit
+ fixup_branch lws_exit
ldo -EFAULT(%r0),%r21 /* set errno */
nop
nop
nop
nop
+ .previous
/* Two exception table entries, one for the load,
the other for the store. Either return -EFAULT */
@@ -601,10 +613,10 @@ cas_action:
#ifdef __LP64__
/* Pad the address calculation */
.word 0,(2b - linux_gateway_page)
- .dword (3b - 2b)
+ .dword 3b
#else
.word 2b - linux_gateway_page
- .word (3b - 2b)
+ .word 3b
#endif
.previous
@@ -612,10 +624,10 @@ cas_action:
#ifdef __LP64__
/* Pad the address calculation */
.word 0,(1b - linux_gateway_page)
- .dword (3b - 1b)
+ .dword 3b
#else
.word 1b - linux_gateway_page
- .word (3b - 1b)
+ .word 3b
#endif
.previous
Index: arch/parisc/kernel/unaligned.c
===================================================================
RCS file: /var/cvs/linux-2.6/arch/parisc/kernel/unaligned.c,v
retrieving revision 1.8
diff -u -p -r1.8 unaligned.c
--- arch/parisc/kernel/unaligned.c 21 Aug 2004 06:19:33 -0000 1.8
+++ arch/parisc/kernel/unaligned.c 13 Sep 2004 23:31:46 -0000
@@ -23,6 +23,7 @@
#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/module.h>
+#include <asm/uaccess.h>
/* #define DEBUG_UNALIGNED 1 */
@@ -34,8 +35,14 @@
#ifdef __LP64__
#define RFMT "%016lx"
+#define FIXUP_BRANCH(lbl) \
+ "\tb " #lbl "\n"
#else
#define RFMT "%08lx"
+#define FIXUP_BRANCH(lbl) \
+ "\tldil L%%" #lbl ", %%r1\n" \
+ "\tldo R%%" #lbl "(%%r1), %%r1\n" \
+ "\tbv,n %%r0(%%r1)\n"
#endif
/* 1111 1100 0000 0000 0001 0011 1100 0000 */
@@ -134,15 +141,19 @@ static int emulate_ldh(struct pt_regs *r
"1: ldbs 0(%%sr1,%3), %%r20\n"
"2: ldbs 1(%%sr1,%3), %0\n"
" depw %%r20, 23, 24, %0\n"
-" cmpclr,= %%r0, %%r0, %1\n"
-"3: ldo -2(%%r0), %1\n"
-" .section __ex_table,\"a\"\n"
+" copy %%r0, %1\n"
+"3: \n"
+" .section .fixup,\"ax\"\n"
+"4: ldi -2, %1\n"
+ FIXUP_BRANCH(3b)
+" .previous\n"
+" .section __ex_table,\"aw\"\n"
#ifdef __LP64__
-" .dword 1b,(3b-1b)\n"
-" .dword 2b,(3b-2b)\n"
+" .dword 1b,4b\n"
+" .dword 2b,4b\n"
#else
-" .word 1b,(3b-1b)\n"
-" .word 2b,(3b-2b)\n"
+" .word 1b,4b\n"
+" .word 2b,4b\n"
#endif
" .previous\n"
: "=r" (val), "=r" (ret)
@@ -175,15 +186,19 @@ static int emulate_ldw(struct pt_regs *r
" subi 32,%%r19,%%r19\n"
" mtctl %%r19,11\n"
" vshd %0,%%r20,%0\n"
-" cmpclr,= %%r0, %%r0, %1\n"
-"3: ldo -2(%%r0), %1\n"
-" .section __ex_table,\"a\"\n"
+" copy %%r0, %1\n"
+"3: \n"
+" .section .fixup,\"ax\"\n"
+"4: ldi -2, %1\n"
+ FIXUP_BRANCH(3b)
+" .previous\n"
+" .section __ex_table,\"aw\"\n"
#ifdef __LP64__
-" .dword 1b,(3b-1b)\n"
-" .dword 2b,(3b-2b)\n"
+" .dword 1b,4b\n"
+" .dword 2b,4b\n"
#else
-" .word 1b,(3b-1b)\n"
-" .word 2b,(3b-2b)\n"
+" .word 1b,4b\n"
+" .word 2b,4b\n"
#endif
" .previous\n"
: "=r" (val), "=r" (ret)
@@ -222,15 +237,19 @@ static int emulate_ldd(struct pt_regs *r
" subi 64,%%r19,%%r19\n"
" mtsar %%r19\n"
" shrpd %0,%%r20,%%sar,%0\n"
-" cmpclr,= %%r0, %%r0, %1\n"
-"3: ldo -2(%%r0), %1\n"
-" .section __ex_table,\"a\"\n"
+" copy %%r0, %1\n"
+"3: \n"
+" .section .fixup,\"ax\"\n"
+"4: ldi -2, %1\n"
+ FIXUP_BRANCH(3b)
+" .previous\n"
+" .section __ex_table,\"aw\"\n"
#ifdef __LP64__
-" .dword 1b,(3b-1b)\n"
-" .dword 2b,(3b-2b)\n"
+" .dword 1b,4b\n"
+" .dword 2b,4b\n"
#else
-" .word 1b,(3b-1b)\n"
-" .word 2b,(3b-2b)\n"
+" .word 1b,4b\n"
+" .word 2b,4b\n"
#endif
" .previous\n"
: "=r" (val), "=r" (ret)
@@ -250,17 +269,20 @@ static int emulate_ldd(struct pt_regs *r
" mtsar %%r19\n"
" vshd %0,%1,%0\n"
" vshd %1,%%r20,%1\n"
-" cmpclr,= %%r0, %%r0, %2\n"
-"4: ldo -2(%%r0), %2\n"
-" .section __ex_table,\"a\"\n"
+" copy %%r0, %2\n"
+"4: \n"
+" .section .fixup,\"ax\"\n"
+"5: ldi -2, %2\n"
+ FIXUP_BRANCH(4b)
+" .previous\n"
#ifdef __LP64__
-" .dword 1b,(4b-1b)\n"
-" .dword 2b,(4b-2b)\n"
-" .dword 3b,(4b-3b)\n"
-#else
-" .word 1b,(4b-1b)\n"
-" .word 2b,(4b-2b)\n"
-" .word 3b,(4b-3b)\n"
+" .dword 1b,5b\n"
+" .dword 2b,5b\n"
+" .dword 3b,5b\n"
+#else
+" .word 1b,5b\n"
+" .word 2b,5b\n"
+" .word 3b,5b\n"
#endif
" .previous\n"
: "=r" (valh), "=r" (vall), "=r" (ret)
@@ -296,15 +318,19 @@ static int emulate_sth(struct pt_regs *r
" extrw,u %1, 23, 8, %%r19\n"
"1: stb %1, 1(%%sr1, %2)\n"
"2: stb %%r19, 0(%%sr1, %2)\n"
-" cmpclr,= %%r0, %%r0, %0\n"
-"3: ldo -2(%%r0), %0\n"
-" .section __ex_table,\"a\"\n"
+" copy %%r0, %0\n"
+"3: \n"
+" .section .fixup,\"ax\"\n"
+"4: ldi -2, %0\n"
+ FIXUP_BRANCH(3b)
+" .previous\n"
+" .section __ex_table,\"aw\"\n"
#ifdef __LP64__
-" .dword 1b,(3b-1b)\n"
-" .dword 2b,(3b-2b)\n"
+" .dword 1b,4b\n"
+" .dword 2b,4b\n"
#else
-" .word 1b,(3b-1b)\n"
-" .word 2b,(3b-2b)\n"
+" .word 1b,4b\n"
+" .word 2b,4b\n"
#endif
" .previous\n"
: "=r" (ret)
@@ -346,15 +372,19 @@ static int emulate_stw(struct pt_regs *r
" or %%r1, %%r21, %%r21\n"
" stw %%r20,0(%%sr1,%2)\n"
" stw %%r21,4(%%sr1,%2)\n"
-" cmpclr,= %%r0, %%r0, %0\n"
-"3: ldo -2(%%r0), %0\n"
-" .section __ex_table,\"a\"\n"
+" copy %%r0, %0\n"
+"3: \n"
+" .section .fixup,\"ax\"\n"
+"4: ldi -2, %0\n"
+ FIXUP_BRANCH(3b)
+" .previous\n"
+" .section __ex_table,\"aw\"\n"
#ifdef __LP64__
-" .dword 1b,(3b-1b)\n"
-" .dword 2b,(3b-2b)\n"
+" .dword 1b,4b\n"
+" .dword 2b,4b\n"
#else
-" .word 1b,(3b-1b)\n"
-" .word 2b,(3b-2b)\n"
+" .word 1b,4b\n"
+" .word 2b,4b\n"
#endif
" .previous\n"
: "=r" (ret)
@@ -399,19 +429,23 @@ static int emulate_std(struct pt_regs *r
" or %%r1, %%r21, %%r21\n"
"3: std %%r20,0(%%sr1,%2)\n"
"4: std %%r21,8(%%sr1,%2)\n"
-" cmpclr,= %%r0, %%r0, %0\n"
-"5: ldo -2(%%r0), %0\n"
-" .section __ex_table,\"a\"\n"
+" copy %%r0, %0\n"
+"5: \n"
+" .section .fixup,\"ax\"\n"
+"6: ldi -2, %0\n"
+ FIXUP_BRANCH(5b)
+" .previous\n"
+" .section __ex_table,\"aw\"\n"
#ifdef __LP64__
-" .dword 1b,(5b-1b)\n"
-" .dword 2b,(5b-2b)\n"
-" .dword 3b,(5b-3b)\n"
-" .dword 4b,(5b-4b)\n"
-#else
-" .word 1b,(5b-1b)\n"
-" .word 2b,(5b-2b)\n"
-" .word 3b,(5b-3b)\n"
-" .word 4b,(5b-4b)\n"
+" .dword 1b,6b\n"
+" .dword 2b,6b\n"
+" .dword 3b,6b\n"
+" .dword 4b,6b\n"
+#else
+" .word 1b,6b\n"
+" .word 2b,6b\n"
+" .word 3b,6b\n"
+" .word 4b,6b\n"
#endif
" .previous\n"
: "=r" (ret)
@@ -438,21 +472,25 @@ static int emulate_std(struct pt_regs *r
"3: stw %1,0(%%sr1,%1)\n"
"4: stw %%r1,4(%%sr1,%3)\n"
"5: stw %2,8(%%sr1,%3)\n"
-" cmpclr,= %%r0, %%r0, %0\n"
-"6: ldo -2(%%r0), %0\n"
-" .section __ex_table,\"a\"\n"
+" copy %%r0, %0\n"
+"6: \n"
+" .section .fixup,\"ax\"\n"
+"7: ldi -2, %0\n"
+ FIXUP_BRANCH(6b)
+" .previous\n"
+" .section __ex_table,\"aw\"\n"
#ifdef __LP64__
-" .dword 1b,(6b-1b)\n"
-" .dword 2b,(6b-2b)\n"
-" .dword 3b,(6b-3b)\n"
-" .dword 4b,(6b-4b)\n"
-" .dword 5b,(6b-5b)\n"
-#else
-" .word 1b,(6b-1b)\n"
-" .word 2b,(6b-2b)\n"
-" .word 3b,(6b-3b)\n"
-" .word 4b,(6b-4b)\n"
-" .word 5b,(6b-5b)\n"
+" .dword 1b,7b\n"
+" .dword 2b,7b\n"
+" .dword 3b,7b\n"
+" .dword 4b,7b\n"
+" .dword 5b,7b\n"
+#else
+" .word 1b,7b\n"
+" .word 2b,7b\n"
+" .word 3b,7b\n"
+" .word 4b,7b\n"
+" .word 5b,7b\n"
#endif
" .previous\n"
: "=r" (ret)
Index: arch/parisc/lib/Makefile
===================================================================
RCS file: /var/cvs/linux-2.6/arch/parisc/lib/Makefile,v
retrieving revision 1.2
diff -u -p -r1.2 Makefile
--- arch/parisc/lib/Makefile 1 Jul 2004 18:30:36 -0000 1.2
+++ arch/parisc/lib/Makefile 13 Sep 2004 23:31:46 -0000
@@ -2,6 +2,6 @@
# Makefile for parisc-specific library files
#
-lib-y := lusercopy.o bitops.o checksum.o io.o memset.o
+lib-y := lusercopy.o bitops.o checksum.o io.o memset.o fixup.o
lib-$(CONFIG_SMP) += debuglocks.o
Index: arch/parisc/lib/fixup.S
===================================================================
RCS file: arch/parisc/lib/fixup.S
diff -N arch/parisc/lib/fixup.S
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ arch/parisc/lib/fixup.S 13 Sep 2004 23:31:46 -0000
@@ -0,0 +1,84 @@
+/*
+ * Linux/PA-RISC Project (http://www.parisc-linux.org/)
+ *
+ * Copyright (C) 2004 Randolph Chung <tausq@debian.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+#include <linux/config.h>
+#include <asm/offsets.h>
+#include <asm/assembly.h>
+#include <asm/errno.h>
+
+#ifdef CONFIG_SMP
+ .macro get_fault_ip t1 t2
+ addil LT'__per_cpu_offset,\t1
+ LDREG RT'__per_cpu_offset(\t1),\t1
+ /* t2 = smp_processor_id() */
+ mfctl 30,\t2
+ ldw TI_CPU(\t2),\t2
+#ifdef __LP64__
+ extrd,u \t2,63,32,\t2
+#endif
+ /* t2 = &__per_cpu_offset[smp_processor_id()]; */
+ LDREG,s \t2(\t1),\t2
+ addil LT'per_cpu__exception_data,\t1
+ LDREG RT'per_cpu__exception_data(\t1),\t1
+ /* t1 = &__get_cpu_var(exception_data) */
+ add,l \t1,\t2,\t1
+ /* t1 = t1->fault_ip */
+ LDREG EXCDATA_IP(\t1), \t1
+ .endm
+#else
+ .macro get_fault_ip t1 t2
+ /* t1 = &__get_cpu_var(exception_data) */
+ addil LT'per_cpu__exception_data,\t1
+ LDREG RT'per_cpu__exception_data(\t1),\t2
+ /* t1 = t1->fault_ip */
+ LDREG EXCDATA_IP(\t2), \t1
+ .endm
+#endif
+
+ .text
+
+ .export fixup_get_user_skip_1
+fixup_get_user_skip_1:
+ get_fault_ip %r1,%r8
+ ldo 4(%r1), %r1
+ ldi -EFAULT, %r8
+ bv %r0(%r1)
+ copy %r0, %r9
+
+ .export fixup_get_user_skip_2
+fixup_get_user_skip_2:
+ get_fault_ip %r1,%r8
+ ldo 8(%r1), %r1
+ ldi -EFAULT, %r8
+ bv %r0(%r1)
+ copy %r0, %r9
+
+ .export fixup_put_user_skip_1
+fixup_put_user_skip_1:
+ get_fault_ip %r1,%r8
+ ldo 4(%r1), %r1
+ bv %r0(%r1)
+ ldi -EFAULT, %r8
+
+ .export fixup_put_user_skip_2
+fixup_put_user_skip_2:
+ get_fault_ip %r1,%r8
+ ldo 8(%r1), %r1
+ bv %r0(%r1)
+ ldi -EFAULT, %r8
Index: arch/parisc/lib/lusercopy.S
===================================================================
RCS file: /var/cvs/linux-2.6/arch/parisc/lib/lusercopy.S,v
retrieving revision 1.3
diff -u -p -r1.3 lusercopy.S
--- arch/parisc/lib/lusercopy.S 17 Jan 2004 06:39:24 -0000 1.3
+++ arch/parisc/lib/lusercopy.S 13 Sep 2004 23:31:46 -0000
@@ -53,6 +53,18 @@
mtsp %r1,%sr1
.endm
+#ifndef __LP64__
+ .macro fixup_branch lbl
+ b \lbl
+ .endm
+#else
+ .macro fixup_branch lbl
+ ldil L%\lbl, %r1
+ ldo R%\lbl(%r1), %r1
+ bv,n %r0(%r1)
+ .endm
+#endif
+
/*
* unsigned long
* lcopy_to_user(void *to, const void *from, unsigned long n)
@@ -77,14 +89,16 @@ $lctu_done:
copy %r24,%r28
.exit
-2: b $lctu_done
+ .section .fixup,"ax"
+2: fixup_branch $lctu_done
ldo 1(%r24),%r24
+ .previous
- .section __ex_table,"a"
+ .section __ex_table,"aw"
#ifdef __LP64__
- .dword 1b,(2b-1b)
+ .dword 1b,2b
#else
- .word 1b,(2b-1b)
+ .word 1b,2b
#endif
.previous
@@ -118,18 +132,20 @@ $lcfu_done:
copy %r24,%r28
.exit
+ .section .fixup,"ax"
2: copy %r24,%r23
$lcfu_zero_loop:
addib,<> -1,%r23,$lcfu_zero_loop
stbs,ma %r0,1(%r26)
- b $lcfu_done
+ fixup_branch $lcfu_done
nop
+ .previous
- .section __ex_table,"a"
+ .section __ex_table,"aw"
#ifdef __LP64__
- .dword 1b,(2b-1b)
+ .dword 1b,2b
#else
- .word 1b,(2b-1b)
+ .word 1b,2b
#endif
.previous
@@ -159,14 +175,16 @@ $lciu_done:
copy %r24,%r28
.exit
-2: b $lciu_done
+ .section .fixup,"ax"
+2: fixup_branch $lciu_done
ldo 1(%r24),%r24
+ .previous
- .section __ex_table,"a"
+ .section __ex_table,"aw"
#ifdef __LP64__
- .dword 1b,(2b-1b)
+ .dword 1b,2b
#else
- .word 1b,(2b-1b)
+ .word 1b,2b
#endif
.previous
@@ -201,16 +219,18 @@ $lsfu_exit:
nop
.exit
-3: b $lsfu_exit
+ .section .fixup,"ax"
+3: fixup_branch $lsfu_exit
ldi -EFAULT,%r28
+ .previous
- .section __ex_table,"a"
+ .section __ex_table,"aw"
#ifdef __LP64__
- .dword 1b,(3b-1b)
- .dword 2b,(3b-2b)
+ .dword 1b,3b
+ .dword 2b,3b
#else
- .word 1b,(3b-1b)
- .word 2b,(3b-2b)
+ .word 1b,3b
+ .word 2b,3b
#endif
.previous
@@ -239,14 +259,16 @@ $lclu_done:
copy %r25,%r28
.exit
-2: b $lclu_done
+ .section .fixup,"ax"
+2: fixup_branch $lclu_done
ldo 1(%r25),%r25
+ .previous
- .section __ex_table,"a"
+ .section __ex_table,"aw"
#ifdef __LP64__
- .dword 1b,(2b-1b)
+ .dword 1b,2b
#else
- .word 1b,(2b-1b)
+ .word 1b,2b
#endif
.previous
@@ -282,16 +304,18 @@ $lslen_nzero:
b $lslen_done
ldo 1(%r26),%r26 /* special case for N == 0 */
-3: b $lslen_done
+ .section .fixup,"ax"
+3: fixup_branch $lslen_done
copy %r24,%r26 /* reset r26 so 0 is returned on fault */
+ .previous
- .section __ex_table,"a"
+ .section __ex_table,"aw"
#ifdef __LP64__
- .dword 1b,(3b-1b)
- .dword 2b,(3b-2b)
+ .dword 1b,3b
+ .dword 2b,3b
#else
- .word 1b,(3b-1b)
- .word 2b,(3b-2b)
+ .word 1b,3b
+ .word 2b,3b
#endif
.previous
Index: arch/parisc/mm/fault.c
===================================================================
RCS file: /var/cvs/linux-2.6/arch/parisc/mm/fault.c,v
retrieving revision 1.1
diff -u -p -r1.1 fault.c
--- arch/parisc/mm/fault.c 29 Jul 2003 17:00:42 -0000 1.1
+++ arch/parisc/mm/fault.c 13 Sep 2004 23:31:46 -0000
@@ -36,6 +36,9 @@
#define BITSSET 0x1c0 /* for identifying LDCW */
+
+DEFINE_PER_CPU(struct exception_data, exception_data);
+
/*
* parisc_acctyp(unsigned int inst) --
* Given a PA-RISC memory access instruction, determine if the
@@ -234,13 +237,16 @@ no_context:
fix = search_exception_tables(regs->iaoq[0]);
if (fix) {
+ struct exception_data *d;
+
+printk("applying fixup for 0x%lx, fixup at 0x%lx\n", regs->iaoq[0], fix->fixup & ~3);
- if (fix->skip & 1)
- regs->gr[8] = -EFAULT;
- if (fix->skip & 2)
- regs->gr[9] = 0;
+ d = &__get_cpu_var(exception_data);
+ d->fault_ip = regs->iaoq[0];
+ d->fault_space = regs->isr;
+ d->fault_addr = regs->ior;
- regs->iaoq[0] += ((fix->skip) & ~3);
+ regs->iaoq[0] = ((fix->fixup) & ~3);
/*
* NOTE: In some cases the faulting instruction
Index: include/asm-parisc/uaccess.h
===================================================================
RCS file: /var/cvs/linux-2.6/include/asm-parisc/uaccess.h,v
retrieving revision 1.13
diff -u -p -r1.13 uaccess.h
--- include/asm-parisc/uaccess.h 4 Feb 2004 18:24:55 -0000 1.13
+++ include/asm-parisc/uaccess.h 13 Sep 2004 23:31:47 -0000
@@ -54,16 +54,21 @@ extern int __put_user_bad(void);
/*
* The exception table contains two values: the first is an address
* for an instruction that is allowed to fault, and the second is
- * the number of bytes to skip if a fault occurs. We also support in
- * two bit flags: 0x2 tells the exception handler to clear register
- * r9 and 0x1 tells the exception handler to put -EFAULT in r8.
- * This allows us to handle the simple cases for put_user and
- * get_user without having to have .fixup sections.
+ * the address to the fixup routine. We also support two bit flags:
+ * 0x2 tells the exception handler to store the faulting address in
+ * r9 and 0x1 tells the exception handler to store the faulting
+ * insn in r8.
*/
struct exception_table_entry {
unsigned long insn; /* address of insn that is allowed to fault. */
- long skip; /* pcoq skip | r9 clear flag | r8 -EFAULT flag */
+ long fixup; /* fixup | r9 ior flag | r8 iir flag */
+};
+
+struct exception_data {
+ unsigned long fault_ip;
+ unsigned long fault_space;
+ unsigned long fault_addr;
};
#define __get_user(x,ptr) \
@@ -97,40 +102,32 @@ struct exception_table_entry {
#ifdef __LP64__
#define __get_kernel_asm(ldx,ptr) \
__asm__("\n1:\t" ldx "\t0(%2),%0\n" \
- "2:\n" \
- "\t.section __ex_table,\"aw\"\n" \
- "\t.dword\t1b\n" \
- "\t.dword\t(2b-1b)+3\n" \
- "\t.previous" \
+ "\t.section __ex_table,\"aw\"\n" \
+ "\t.dword\t1b,fixup_get_user_skip_1\n" \
+ "\t.previous" \
: "=r"(__gu_val), "=r"(__gu_err) \
: "r"(ptr), "1"(__gu_err));
#define __get_user_asm(ldx,ptr) \
__asm__("\n1:\t" ldx "\t0(%%sr3,%2),%0\n" \
- "2:\n" \
- "\t.section __ex_table,\"aw\"\n" \
- "\t.dword\t1b\n" \
- "\t.dword\t(2b-1b)+3\n" \
- "\t.previous" \
+ "\t.section __ex_table,\"aw\"\n" \
+ "\t.dword\t1b,fixup_get_user_skip_1\n" \
+ "\t.previous" \
: "=r"(__gu_val), "=r"(__gu_err) \
: "r"(ptr), "1"(__gu_err));
#else
#define __get_kernel_asm(ldx,ptr) \
__asm__("\n1:\t" ldx "\t0(%2),%0\n" \
- "2:\n" \
- "\t.section __ex_table,\"aw\"\n" \
- "\t.word\t1b\n" \
- "\t.word\t(2b-1b)+3\n" \
- "\t.previous" \
+ "\t.section __ex_table,\"aw\"\n" \
+ "\t.word\t1b,fixup_get_user_skip_1\n" \
+ "\t.previous" \
: "=r"(__gu_val), "=r"(__gu_err) \
: "r"(ptr), "1"(__gu_err));
#define __get_user_asm(ldx,ptr) \
__asm__("\n1:\t" ldx "\t0(%%sr3,%2),%0\n" \
- "2:\n" \
- "\t.section __ex_table,\"aw\"\n" \
- "\t.word\t1b\n" \
- "\t.word\t(2b-1b)+3\n" \
+ "\t.section __ex_table,\"aw\"\n" \
+ "\t.word\t1b,fixup_get_user_skip_1\n" \
"\t.previous" \
: "=r"(__gu_val), "=r"(__gu_err) \
: "r"(ptr), "1"(__gu_err));
@@ -138,7 +135,7 @@ struct exception_table_entry {
#define __put_user(x,ptr) \
({ \
- register long __pu_err __asm__ ("r8") = 0; \
+ register long __pu_err __asm__ ("r8") = 0; \
\
if (segment_eq(get_fs(),KERNEL_DS)) { \
switch (sizeof(*(ptr))) { \
@@ -172,21 +169,17 @@ struct exception_table_entry {
#define __put_kernel_asm(stx,x,ptr) \
__asm__ __volatile__ ( \
"\n1:\t" stx "\t%2,0(%1)\n" \
- "2:\n" \
- "\t.section __ex_table,\"aw\"\n" \
- "\t.dword\t1b\n" \
- "\t.dword\t(2b-1b)+1\n" \
- "\t.previous" \
+ "\t.section __ex_table,\"aw\"\n" \
+ "\t.dword\t1b,fixup_put_user_skip_1\n" \
+ "\t.previous" \
: "=r"(__pu_err) \
: "r"(ptr), "r"(x), "0"(__pu_err))
#define __put_user_asm(stx,x,ptr) \
__asm__ __volatile__ ( \
"\n1:\t" stx "\t%2,0(%%sr3,%1)\n" \
- "2:\n" \
- "\t.section __ex_table,\"aw\"\n" \
- "\t.dword\t1b\n" \
- "\t.dword\t(2b-1b)+1\n" \
+ "\t.section __ex_table,\"aw\"\n" \
+ "\t.dword\t1b,fixup_put_user_skip_1\n" \
"\t.previous" \
: "=r"(__pu_err) \
: "r"(ptr), "r"(x), "0"(__pu_err))
@@ -194,10 +187,8 @@ struct exception_table_entry {
#define __put_kernel_asm(stx,x,ptr) \
__asm__ __volatile__ ( \
"\n1:\t" stx "\t%2,0(%1)\n" \
- "2:\n" \
- "\t.section __ex_table,\"aw\"\n" \
- "\t.word\t1b\n" \
- "\t.word\t(2b-1b)+1\n" \
+ "\t.section __ex_table,\"aw\"\n" \
+ "\t.word\t1b,fixup_put_user_skip_1\n" \
"\t.previous" \
: "=r"(__pu_err) \
: "r"(ptr), "r"(x), "0"(__pu_err))
@@ -205,49 +196,41 @@ struct exception_table_entry {
#define __put_user_asm(stx,x,ptr) \
__asm__ __volatile__ ( \
"\n1:\t" stx "\t%2,0(%%sr3,%1)\n" \
- "2:\n" \
- "\t.section __ex_table,\"aw\"\n" \
- "\t.word\t1b\n" \
- "\t.word\t(2b-1b)+1\n" \
+ "\t.section __ex_table,\"aw\"\n" \
+ "\t.word\t1b,fixup_put_user_skip_1\n" \
"\t.previous" \
: "=r"(__pu_err) \
: "r"(ptr), "r"(x), "0"(__pu_err))
-static inline void __put_kernel_asm64(u64 x, void *ptr)
-{
- u32 hi = x>>32;
- u32 lo = x&0xffffffff;
- __asm__ __volatile__ (
- "\n1:\tstw %1,0(%0)\n"
- "\n2:\tstw %2,4(%0)\n"
- "3:\n"
- "\t.section __ex_table,\"aw\"\n"
- "\t.word\t1b\n"
- "\t.word\t(3b-1b)+1\n"
- "\t.word\t2b\n"
- "\t.word\t(3b-2b)+1\n"
- "\t.previous"
- : : "r"(ptr), "r"(hi), "r"(lo));
-
-}
-
-static inline void __put_user_asm64(u64 x, void *ptr)
-{
- u32 hi = x>>32;
- u32 lo = x&0xffffffff;
- __asm__ __volatile__ (
- "\n1:\tstw %1,0(%%sr3,%0)\n"
- "\n2:\tstw %2,4(%%sr3,%0)\n"
- "3:\n"
- "\t.section __ex_table,\"aw\"\n"
- "\t.word\t1b\n"
- "\t.word\t(3b-1b)+1\n"
- "\t.word\t2b\n"
- "\t.word\t(3b-2b)+1\n"
- "\t.previous"
- : : "r"(ptr), "r"(hi), "r"(lo));
+#define __put_kernel_asm64(_x,ptr) do { \
+ u64 x = (u64)_x; \
+ u32 hi = x>>32; \
+ u32 lo = x&0xffffffff; \
+ __asm__ __volatile__ ( \
+ "\n1:\tstw %2,0(%1)\n" \
+ "\n2:\tstw %3,4(%1)\n" \
+ "\t.section __ex_table,\"aw\"\n" \
+ "\t.word\t1b,fixup_put_user_skip_2\n" \
+ "\t.word\t2b,fixup_put_user_skip_1\n" \
+ "\t.previous" \
+ : "=r"(__pu_err) \
+ : "r"(ptr), "r"(hi), "r"(lo), "0"(__pu_err)); \
+} while (0)
-}
+#define __put_user_asm64(_x,ptr) do { \
+ u64 x = (u64)_x; \
+ u32 hi = x>>32; \
+ u32 lo = x&0xffffffff; \
+ __asm__ __volatile__ ( \
+ "\n1:\tstw %2,0(%%sr3,%1)\n" \
+ "\n2:\tstw %3,4(%%sr3,%1)\n" \
+ "\t.section __ex_table,\"aw\"\n" \
+ "\t.word\t1b,fixup_get_user_skip_2\n" \
+ "\t.word\t2b,fixup_get_user_skip_1\n" \
+ "\t.previous" \
+ : "=r"(__pu_err) \
+ : "r"(ptr), "r"(hi), "r"(lo), "0"(__pu_err)); \
+} while (0)
#endif /* !__LP64__ */
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next prev parent reply other threads:[~2004-09-13 23:37 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-09-11 16:53 [parisc-linux] [RFC] Revamp exception handling in the kernel Randolph Chung
2004-09-11 22:49 ` John David Anglin
2004-09-12 13:10 ` Carlos O'Donell
2004-09-12 13:47 ` Carlos O'Donell
2004-09-12 13:58 ` James Bottomley
2004-09-12 14:29 ` Carlos O'Donell
2004-09-12 15:03 ` James Bottomley
2004-09-12 16:15 ` Randolph Chung
2004-09-12 17:54 ` Carlos O'Donell
2004-09-12 18:48 ` Randolph Chung
2004-09-12 19:19 ` Carlos O'Donell
2004-09-13 23:37 ` Randolph Chung [this message]
2004-09-14 2:37 ` Randolph Chung
2004-09-14 18:52 ` Joel Soete
[not found] <20040914160613.GA28659@tausq.org>
2004-09-14 22:36 ` Carlos O'Donell
[not found] ` <41487C05.3010606@tiscali.be>
[not found] ` <41487D4C.2020004@tiscali.be>
2004-09-16 14:31 ` Carlos O'Donell
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