From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Linus Torvalds <torvalds@osdl.org>, Andrew Morton <akpm@osdl.org>
Cc: Linux Kernel Development <linux-kernel@vger.kernel.org>,
Geert Uytterhoeven <geert@linux-m68k.org>
Subject: [PATCH 346] M68k RMW accesses
Date: Thu, 1 Jan 2004 21:01:50 +0100 [thread overview]
Message-ID: <200401012001.i01K1oZM031721@callisto.of.borg> (raw)
M68k: Avoid bus fault for certain RMW accesses (from Roman Zippel)
--- linux-2.6.0/arch/m68k/kernel/traps.c 8 Oct 2003 20:34:14 -0000 1.1.1.12
+++ linux-m68k-2.6.0/arch/m68k/kernel/traps.c 16 Oct 2003 21:13:34 -0000
@@ -583,12 +583,9 @@
unsigned short mmusr;
unsigned long addr, errorcode;
unsigned short ssw = fp->un.fmtb.ssw;
- int user_space_fault = 1;
#if DEBUG
unsigned long desc;
-#endif
-#if DEBUG
printk ("pid = %x ", current->pid);
printk ("SSW=%#06x ", ssw);
@@ -605,128 +602,116 @@
space_names[ssw & DFC], fp->ptregs.pc);
#endif
- if (fp->ptregs.sr & PS_S) {
- /* kernel fault must be a data fault to user space */
- if (! ((ssw & DF) && ((ssw & DFC) == USER_DATA))) {
- /* instruction fault or kernel data fault! */
- if (ssw & (FC | FB))
- printk ("Instruction fault at %#010lx\n",
- fp->ptregs.pc);
- if (ssw & DF) {
- printk ("Data %s fault at %#010lx in %s (pc=%#lx)\n",
- ssw & RW ? "read" : "write",
- fp->un.fmtb.daddr,
- space_names[ssw & DFC], fp->ptregs.pc);
- }
- printk ("BAD KERNEL BUSERR\n");
- die_if_kernel("Oops",&fp->ptregs,0);
- force_sig(SIGKILL, current);
- return;
- }
- } else {
- /* user fault */
- if (!(ssw & (FC | FB)) && !(ssw & DF))
- /* not an instruction fault or data fault! BAD */
- panic ("USER BUSERR w/o instruction or data fault");
- user_space_fault = 1;
-#if DEBUG
- printk("User space bus-error\n");
-#endif
- }
-
/* ++andreas: If a data fault and an instruction fault happen
at the same time map in both pages. */
/* First handle the data fault, if any. */
- if (ssw & DF)
- {
- addr = fp->un.fmtb.daddr;
+ if (ssw & DF) {
+ addr = fp->un.fmtb.daddr;
- mmusr = MMU_I;
- if (user_space_fault) {
#if DEBUG
- asm volatile ("ptestr #1,%2@,#7,%0\n\t"
- "pmove %/psr,%1@"
- : "=a&" (desc)
- : "a" (&temp), "a" (addr));
+ asm volatile ("ptestr %3,%2@,#7,%0\n\t"
+ "pmove %%psr,%1@"
+ : "=a&" (desc)
+ : "a" (&temp), "a" (addr), "d" (ssw));
#else
- asm volatile ("ptestr #1,%1@,#7\n\t"
- "pmove %/psr,%0@"
- : : "a" (&temp), "a" (addr));
-#endif
- mmusr = temp;
- }
-
-#if DEBUG
- printk ("mmusr is %#x for addr %#lx in task %p\n",
- mmusr, addr, current);
- printk ("descriptor address is %#lx, contents %#lx\n",
- __va(desc), *(unsigned long *)__va(desc));
+ asm volatile ("ptestr %2,%1@,#7\n\t"
+ "pmove %%psr,%0@"
+ : : "a" (&temp), "a" (addr), "d" (ssw));
#endif
+ mmusr = temp;
- errorcode = (mmusr & MMU_I) ? 0 : 1;
- if (!(ssw & RW) || (ssw & RM))
- errorcode |= 2;
-
- if (mmusr & (MMU_I | MMU_WP)) {
- /* Don't try to do anything further if an exception was
- handled. */
- if (do_page_fault (&fp->ptregs, addr, errorcode) < 0)
+#if DEBUG
+ printk("mmusr is %#x for addr %#lx in task %p\n",
+ mmusr, addr, current);
+ printk("descriptor address is %#lx, contents %#lx\n",
+ __va(desc), *(unsigned long *)__va(desc));
+#endif
+
+ errorcode = (mmusr & MMU_I) ? 0 : 1;
+ if (!(ssw & RW) || (ssw & RM))
+ errorcode |= 2;
+
+ if (mmusr & (MMU_I | MMU_WP)) {
+ if (ssw & 4) {
+ printk("Data %s fault at %#010lx in %s (pc=%#lx)\n",
+ ssw & RW ? "read" : "write",
+ fp->un.fmtb.daddr,
+ space_names[ssw & DFC], fp->ptregs.pc);
+ goto buserr;
+ }
+ /* Don't try to do anything further if an exception was
+ handled. */
+ if (do_page_fault (&fp->ptregs, addr, errorcode) < 0)
+ return;
+ } else if (!(mmusr & MMU_I)) {
+ /* propably a 020 cas fault */
+ if (!(ssw & RM))
+ printk("unexpected bus error (%#x,%#x)\n", ssw, mmusr);
+ } else if (mmusr & (MMU_B|MMU_L|MMU_S)) {
+ printk("invalid %s access at %#lx from pc %#lx\n",
+ !(ssw & RW) ? "write" : "read", addr,
+ fp->ptregs.pc);
+ die_if_kernel("Oops",&fp->ptregs,mmusr);
+ force_sig(SIGSEGV, current);
return;
- } else if (mmusr & (MMU_B|MMU_L|MMU_S)) {
- printk ("invalid %s access at %#lx from pc %#lx\n",
- !(ssw & RW) ? "write" : "read", addr,
- fp->ptregs.pc);
- die_if_kernel("Oops",&fp->ptregs,mmusr);
- force_sig(SIGSEGV, current);
- return;
- } else {
+ } else {
#if 0
- static volatile long tlong;
+ static volatile long tlong;
#endif
- printk ("weird %s access at %#lx from pc %#lx (ssw is %#x)\n",
- !(ssw & RW) ? "write" : "read", addr,
- fp->ptregs.pc, ssw);
- asm volatile ("ptestr #1,%1@,#0\n\t"
- "pmove %/psr,%0@"
- : /* no outputs */
- : "a" (&temp), "a" (addr));
- mmusr = temp;
+ printk("weird %s access at %#lx from pc %#lx (ssw is %#x)\n",
+ !(ssw & RW) ? "write" : "read", addr,
+ fp->ptregs.pc, ssw);
+ asm volatile ("ptestr #1,%1@,#0\n\t"
+ "pmove %%psr,%0@"
+ : /* no outputs */
+ : "a" (&temp), "a" (addr));
+ mmusr = temp;
- printk ("level 0 mmusr is %#x\n", mmusr);
+ printk ("level 0 mmusr is %#x\n", mmusr);
#if 0
- asm volatile ("pmove %/tt0,%0@"
- : /* no outputs */
- : "a" (&tlong));
- printk ("tt0 is %#lx, ", tlong);
- asm volatile ("pmove %/tt1,%0@"
- : /* no outputs */
- : "a" (&tlong));
- printk ("tt1 is %#lx\n", tlong);
+ asm volatile ("pmove %%tt0,%0@"
+ : /* no outputs */
+ : "a" (&tlong));
+ printk("tt0 is %#lx, ", tlong);
+ asm volatile ("pmove %%tt1,%0@"
+ : /* no outputs */
+ : "a" (&tlong));
+ printk("tt1 is %#lx\n", tlong);
#endif
#if DEBUG
- printk("Unknown SIGSEGV - 1\n");
+ printk("Unknown SIGSEGV - 1\n");
#endif
- die_if_kernel("Oops",&fp->ptregs,mmusr);
- force_sig(SIGSEGV, current);
- return;
- }
-
- /* setup an ATC entry for the access about to be retried */
- if (!(ssw & RW))
- asm volatile ("ploadw %1,%0@" : /* no outputs */
- : "a" (addr), "d" (ssw));
- else
- asm volatile ("ploadr %1,%0@" : /* no outputs */
- : "a" (addr), "d" (ssw));
- }
+ die_if_kernel("Oops",&fp->ptregs,mmusr);
+ force_sig(SIGSEGV, current);
+ return;
+ }
+
+ /* setup an ATC entry for the access about to be retried */
+ if (!(ssw & RW) || (ssw & RM))
+ asm volatile ("ploadw %1,%0@" : /* no outputs */
+ : "a" (addr), "d" (ssw));
+ else
+ asm volatile ("ploadr %1,%0@" : /* no outputs */
+ : "a" (addr), "d" (ssw));
+ }
/* Now handle the instruction fault. */
if (!(ssw & (FC|FB)))
return;
+ if (fp->ptregs.sr & PS_S) {
+ printk("Instruction fault at %#010lx\n",
+ fp->ptregs.pc);
+ buserr:
+ printk ("BAD KERNEL BUSERR\n");
+ die_if_kernel("Oops",&fp->ptregs,0);
+ force_sig(SIGKILL, current);
+ return;
+ }
+
/* get the fault address */
if (fp->ptregs.format == 10)
addr = fp->ptregs.pc + 4;
@@ -740,21 +725,18 @@
should still create the ATC entry. */
goto create_atc_entry;
- mmusr = MMU_I;
- if (user_space_fault) {
#if DEBUG
- asm volatile ("ptestr #1,%2@,#7,%0\n\t"
- "pmove %/psr,%1@"
- : "=a&" (desc)
- : "a" (&temp), "a" (addr));
+ asm volatile ("ptestr #1,%2@,#7,%0\n\t"
+ "pmove %%psr,%1@"
+ : "=a&" (desc)
+ : "a" (&temp), "a" (addr));
#else
- asm volatile ("ptestr #1,%1@,#7\n\t"
- "pmove %/psr,%0@"
- : : "a" (&temp), "a" (addr));
+ asm volatile ("ptestr #1,%1@,#7\n\t"
+ "pmove %%psr,%0@"
+ : : "a" (&temp), "a" (addr));
#endif
- mmusr = temp;
- }
-
+ mmusr = temp;
+
#ifdef DEBUG
printk ("mmusr is %#x for addr %#lx in task %p\n",
mmusr, addr, current);
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
reply other threads:[~2004-01-01 20:46 UTC|newest]
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