Linux-2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
diff --git a/arch/cris/arch-v10/lib/usercopy.c b/arch/cris/arch-v10/lib/usercopy.c
new file mode 100644
index 0000000..43778d5
--- /dev/null
+++ b/arch/cris/arch-v10/lib/usercopy.c
@@ -0,0 +1,523 @@
+/*
+ * User address space access functions.
+ * The non-inlined parts of asm-cris/uaccess.h are here.
+ *
+ * Copyright (C) 2000, Axis Communications AB.
+ *
+ * Written by Hans-Peter Nilsson.
+ * Pieces used from memcpy, originally by Kenny Ranerup long time ago.
+ */
+
+#include <asm/uaccess.h>
+
+/* Asm:s have been tweaked (within the domain of correctness) to give
+   satisfactory results for "gcc version 2.96 20000427 (experimental)".
+
+   Check regularly...
+
+   Note that the PC saved at a bus-fault is the address *after* the
+   faulting instruction, which means the branch-target for instructions in
+   delay-slots for taken branches.  Note also that the postincrement in
+   the instruction is performed regardless of bus-fault; the register is
+   seen updated in fault handlers.
+
+   Oh, and on the code formatting issue, to whomever feels like "fixing
+   it" to Conformity: I'm too "lazy", but why don't you go ahead and "fix"
+   string.c too.  I just don't think too many people will hack this file
+   for the code format to be an issue.  */
+
+
+/* Copy to userspace.  This is based on the memcpy used for
+   kernel-to-kernel copying; see "string.c".  */
+
+unsigned long
+__copy_user (void __user *pdst, const void *psrc, unsigned long pn)
+{
+  /* We want the parameters put in special registers.
+     Make sure the compiler is able to make something useful of this.
+     As it is now: r10 -> r13; r11 -> r11 (nop); r12 -> r12 (nop).
+
+     FIXME: Comment for old gcc version.  Check.
+     If gcc was allright, it really would need no temporaries, and no
+     stack space to save stuff on. */
+
+  register char *dst __asm__ ("r13") = pdst;
+  register const char *src __asm__ ("r11") = psrc;
+  register int n __asm__ ("r12") = pn;
+  register int retn __asm__ ("r10") = 0;
+
+
+  /* When src is aligned but not dst, this makes a few extra needless
+     cycles.  I believe it would take as many to check that the
+     re-alignment was unnecessary.  */
+  if (((unsigned long) dst & 3) != 0
+      /* Don't align if we wouldn't copy more than a few bytes; so we
+	 don't have to check further for overflows.  */
+      && n >= 3)
+  {
+    if ((unsigned long) dst & 1)
+    {
+      __asm_copy_to_user_1 (dst, src, retn);
+      n--;
+    }
+
+    if ((unsigned long) dst & 2)
+    {
+      __asm_copy_to_user_2 (dst, src, retn);
+      n -= 2;
+    }
+  }
+
+  /* Decide which copying method to use. */
+  if (n >= 44*2)		/* Break even between movem and
+				   move16 is at 38.7*2, but modulo 44. */
+  {
+    /* For large copies we use 'movem'.  */
+
+    /* It is not optimal to tell the compiler about clobbering any
+       registers; that will move the saving/restoring of those registers
+       to the function prologue/epilogue, and make non-movem sizes
+       suboptimal.
+
+       This method is not foolproof; it assumes that the "asm reg"
+       declarations at the beginning of the function really are used
+       here (beware: they may be moved to temporary registers).
+       This way, we do not have to save/move the registers around into
+       temporaries; we can safely use them straight away.
+
+       If you want to check that the allocation was right; then
+       check the equalities in the first comment.  It should say
+       "r13=r13, r11=r11, r12=r12".  */
+    __asm__ volatile ("\
+	.ifnc %0%1%2%3,$r13$r11$r12$r10					\n\
+	.err								\n\
+	.endif								\n\
+
+	;; Save the registers we'll use in the movem process
+	;; on the stack.
+	subq	11*4,$sp
+	movem	$r10,[$sp]
+
+	;; Now we've got this:
+	;; r11 - src
+	;; r13 - dst
+	;; r12 - n
+
+	;; Update n for the first loop
+	subq	44,$r12
+
+; Since the noted PC of a faulting instruction in a delay-slot of a taken
+; branch, is that of the branch target, we actually point at the from-movem
+; for this case.  There is no ambiguity here; if there was a fault in that
+; instruction (meaning a kernel oops), the faulted PC would be the address
+; after *that* movem.
+
+0:
+	movem	[$r11+],$r10
+	subq   44,$r12
+	bge	0b
+	movem	$r10,[$r13+]
+1:
+	addq   44,$r12  ;; compensate for last loop underflowing n
+
+	;; Restore registers from stack
+	movem [$sp+],$r10
+2:
+	.section .fixup,\"ax\"
+
+; To provide a correct count in r10 of bytes that failed to be copied,
+; we jump back into the loop if the loop-branch was taken.  There is no
+; performance penalty for sany use; the program will segfault soon enough.
+
+3:
+	move.d [$sp],$r10
+	addq 44,$r10
+	move.d $r10,[$sp]
+	jump 0b
+4:
+	movem [$sp+],$r10
+	addq 44,$r10
+	addq 44,$r12
+	jump 2b
+
+	.previous
+	.section __ex_table,\"a\"
+	.dword 0b,3b
+	.dword 1b,4b
+	.previous"
+
+     /* Outputs */ : "=r" (dst), "=r" (src), "=r" (n), "=r" (retn)
+     /* Inputs */ : "0" (dst), "1" (src), "2" (n), "3" (retn));
+
+  }
+
+  /* Either we directly start copying, using dword copying in a loop, or
+     we copy as much as possible with 'movem' and then the last block (<44
+     bytes) is copied here.  This will work since 'movem' will have
+     updated SRC, DST and N.  */
+
+  while (n >= 16)
+  {
+    __asm_copy_to_user_16 (dst, src, retn);
+    n -= 16;
+  }
+
+  /* Having a separate by-four loops cuts down on cache footprint.
+     FIXME:  Test with and without; increasing switch to be 0..15.  */
+  while (n >= 4)
+  {
+    __asm_copy_to_user_4 (dst, src, retn);
+    n -= 4;
+  }
+
+  switch (n)
+  {
+    case 0:
+      break;
+    case 1:
+      __asm_copy_to_user_1 (dst, src, retn);
+      break;
+    case 2:
+      __asm_copy_to_user_2 (dst, src, retn);
+      break;
+    case 3:
+      __asm_copy_to_user_3 (dst, src, retn);
+      break;
+  }
+
+  return retn;
+}
+
+/* Copy from user to kernel, zeroing the bytes that were inaccessible in
+   userland.  The return-value is the number of bytes that were
+   inaccessible.  */
+
+unsigned long
+__copy_user_zeroing (void __user *pdst, const void *psrc, unsigned long pn)
+{
+  /* We want the parameters put in special registers.
+     Make sure the compiler is able to make something useful of this.
+     As it is now: r10 -> r13; r11 -> r11 (nop); r12 -> r12 (nop).
+
+     FIXME: Comment for old gcc version.  Check.
+     If gcc was allright, it really would need no temporaries, and no
+     stack space to save stuff on.  */
+
+  register char *dst __asm__ ("r13") = pdst;
+  register const char *src __asm__ ("r11") = psrc;
+  register int n __asm__ ("r12") = pn;
+  register int retn __asm__ ("r10") = 0;
+
+  /* The best reason to align src is that we then know that a read-fault
+     was for aligned bytes; there's no 1..3 remaining good bytes to
+     pickle.  */
+  if (((unsigned long) src & 3) != 0)
+  {
+    if (((unsigned long) src & 1) && n != 0)
+    {
+      __asm_copy_from_user_1 (dst, src, retn);
+      n--;
+    }
+
+    if (((unsigned long) src & 2) && n >= 2)
+    {
+      __asm_copy_from_user_2 (dst, src, retn);
+      n -= 2;
+    }
+
+    /* We only need one check after the unalignment-adjustments, because
+       if both adjustments were done, either both or neither reference
+       had an exception.  */
+    if (retn != 0)
+      goto copy_exception_bytes;
+  }
+
+  /* Decide which copying method to use. */
+  if (n >= 44*2)		/* Break even between movem and
+				   move16 is at 38.7*2, but modulo 44.
+				   FIXME: We use move4 now.  */
+  {
+    /* For large copies we use 'movem' */
+
+    /* It is not optimal to tell the compiler about clobbering any
+       registers; that will move the saving/restoring of those registers
+       to the function prologue/epilogue, and make non-movem sizes
+       suboptimal.
+
+       This method is not foolproof; it assumes that the "asm reg"
+       declarations at the beginning of the function really are used
+       here (beware: they may be moved to temporary registers).
+       This way, we do not have to save/move the registers around into
+       temporaries; we can safely use them straight away.
+
+       If you want to check that the allocation was right; then
+       check the equalities in the first comment.  It should say
+       "r13=r13, r11=r11, r12=r12" */
+    __asm__ volatile ("
+	.ifnc %0%1%2%3,$r13$r11$r12$r10					\n\
+	.err								\n\
+	.endif								\n\
+
+	;; Save the registers we'll use in the movem process
+	;; on the stack.
+	subq	11*4,$sp
+	movem	$r10,[$sp]
+
+	;; Now we've got this:
+	;; r11 - src
+	;; r13 - dst
+	;; r12 - n
+
+	;; Update n for the first loop
+	subq	44,$r12
+0:
+	movem	[$r11+],$r10
+1:
+	subq   44,$r12
+	bge	0b
+	movem	$r10,[$r13+]
+
+	addq   44,$r12  ;; compensate for last loop underflowing n
+
+	;; Restore registers from stack
+	movem [$sp+],$r10
+4:
+	.section .fixup,\"ax\"
+
+;; Do not jump back into the loop if we fail.  For some uses, we get a
+;; page fault somewhere on the line.  Without checking for page limits,
+;; we don't know where, but we need to copy accurately and keep an
+;; accurate count; not just clear the whole line.  To do that, we fall
+;; down in the code below, proceeding with smaller amounts.  It should
+;; be kept in mind that we have to cater to code like what at one time
+;; was in fs/super.c:
+;;  i = size - copy_from_user((void *)page, data, size);
+;; which would cause repeated faults while clearing the remainder of
+;; the SIZE bytes at PAGE after the first fault.
+;; A caveat here is that we must not fall through from a failing page
+;; to a valid page.
+
+3:
+	movem  [$sp+],$r10
+	addq	44,$r12 ;; Get back count before faulting point.
+	subq	44,$r11 ;; Get back pointer to faulting movem-line.
+	jump	4b	;; Fall through, pretending the fault didn't happen.
+
+	.previous
+	.section __ex_table,\"a\"
+	.dword 1b,3b
+	.previous"
+
+     /* Outputs */ : "=r" (dst), "=r" (src), "=r" (n), "=r" (retn)
+     /* Inputs */ : "0" (dst), "1" (src), "2" (n), "3" (retn));
+
+  }
+
+  /* Either we directly start copying here, using dword copying in a loop,
+     or we copy as much as possible with 'movem' and then the last block
+     (<44 bytes) is copied here.  This will work since 'movem' will have
+     updated src, dst and n.  (Except with failing src.)
+
+     Since we want to keep src accurate, we can't use
+     __asm_copy_from_user_N with N != (1, 2, 4); it updates dst and
+     retn, but not src (by design; it's value is ignored elsewhere).  */
+
+  while (n >= 4)
+  {
+    __asm_copy_from_user_4 (dst, src, retn);
+    n -= 4;
+
+    if (retn)
+      goto copy_exception_bytes;
+  }
+
+  /* If we get here, there were no memory read faults.  */
+  switch (n)
+  {
+    /* These copies are at least "naturally aligned" (so we don't have
+       to check each byte), due to the src alignment code before the
+       movem loop.  The *_3 case *will* get the correct count for retn.  */
+    case 0:
+      /* This case deliberately left in (if you have doubts check the
+	 generated assembly code).  */
+      break;
+    case 1:
+      __asm_copy_from_user_1 (dst, src, retn);
+      break;
+    case 2:
+      __asm_copy_from_user_2 (dst, src, retn);
+      break;
+    case 3:
+      __asm_copy_from_user_3 (dst, src, retn);
+      break;
+  }
+
+  /* If we get here, retn correctly reflects the number of failing
+     bytes.  */
+  return retn;
+
+copy_exception_bytes:
+  /* We already have "retn" bytes cleared, and need to clear the
+     remaining "n" bytes.  A non-optimized simple byte-for-byte in-line
+     memset is preferred here, since this isn't speed-critical code and
+     we'd rather have this a leaf-function than calling memset.  */
+  {
+    char *endp;
+    for (endp = dst + n; dst < endp; dst++)
+      *dst = 0;
+  }
+
+  return retn + n;
+}
+
+/* Zero userspace.  */
+
+unsigned long
+__do_clear_user (void __user *pto, unsigned long pn)
+{
+  /* We want the parameters put in special registers.
+     Make sure the compiler is able to make something useful of this.
+      As it is now: r10 -> r13; r11 -> r11 (nop); r12 -> r12 (nop).
+
+     FIXME: Comment for old gcc version.  Check.
+     If gcc was allright, it really would need no temporaries, and no
+     stack space to save stuff on. */
+
+  register char *dst __asm__ ("r13") = pto;
+  register int n __asm__ ("r12") = pn;
+  register int retn __asm__ ("r10") = 0;
+
+
+  if (((unsigned long) dst & 3) != 0
+     /* Don't align if we wouldn't copy more than a few bytes.  */
+      && n >= 3)
+  {
+    if ((unsigned long) dst & 1)
+    {
+      __asm_clear_1 (dst, retn);
+      n--;
+    }
+
+    if ((unsigned long) dst & 2)
+    {
+      __asm_clear_2 (dst, retn);
+      n -= 2;
+    }
+  }
+
+  /* Decide which copying method to use.
+     FIXME: This number is from the "ordinary" kernel memset.  */
+  if (n >= (1*48))
+  {
+    /* For large clears we use 'movem' */
+
+    /* It is not optimal to tell the compiler about clobbering any
+       call-saved registers; that will move the saving/restoring of
+       those registers to the function prologue/epilogue, and make
+       non-movem sizes suboptimal.
+
+       This method is not foolproof; it assumes that the "asm reg"
+       declarations at the beginning of the function really are used
+       here (beware: they may be moved to temporary registers).
+       This way, we do not have to save/move the registers around into
+       temporaries; we can safely use them straight away.
+
+      If you want to check that the allocation was right; then
+      check the equalities in the first comment.  It should say
+      something like "r13=r13, r11=r11, r12=r12". */
+    __asm__ volatile ("
+	.ifnc %0%1%2,$r13$r12$r10					\n\
+	.err								\n\
+	.endif								\n\
+
+	;; Save the registers we'll clobber in the movem process
+	;; on the stack.  Don't mention them to gcc, it will only be
+	;; upset.
+	subq	11*4,$sp
+	movem	$r10,[$sp]
+
+	clear.d $r0
+	clear.d $r1
+	clear.d $r2
+	clear.d $r3
+	clear.d $r4
+	clear.d $r5
+	clear.d $r6
+	clear.d $r7
+	clear.d $r8
+	clear.d $r9
+	clear.d $r10
+	clear.d $r11
+
+	;; Now we've got this:
+	;; r13 - dst
+	;; r12 - n
+
+	;; Update n for the first loop
+	subq	12*4,$r12
+0:
+	subq   12*4,$r12
+	bge	0b
+	movem	$r11,[$r13+]
+1:
+	addq   12*4,$r12        ;; compensate for last loop underflowing n
+
+	;; Restore registers from stack
+	movem [$sp+],$r10
+2:
+	.section .fixup,\"ax\"
+3:
+	move.d [$sp],$r10
+	addq 12*4,$r10
+	move.d $r10,[$sp]
+	clear.d $r10
+	jump 0b
+
+4:
+	movem [$sp+],$r10
+	addq 12*4,$r10
+	addq 12*4,$r12
+	jump 2b
+
+	.previous
+	.section __ex_table,\"a\"
+	.dword 0b,3b
+	.dword 1b,4b
+	.previous"
+
+     /* Outputs */ : "=r" (dst), "=r" (n), "=r" (retn)
+     /* Inputs */ : "0" (dst), "1" (n), "2" (retn)
+     /* Clobber */ : "r11");
+  }
+
+  while (n >= 16)
+  {
+    __asm_clear_16 (dst, retn);
+    n -= 16;
+  }
+
+  /* Having a separate by-four loops cuts down on cache footprint.
+     FIXME:  Test with and without; increasing switch to be 0..15.  */
+  while (n >= 4)
+  {
+    __asm_clear_4 (dst, retn);
+    n -= 4;
+  }
+
+  switch (n)
+  {
+    case 0:
+      break;
+    case 1:
+      __asm_clear_1 (dst, retn);
+      break;
+    case 2:
+      __asm_clear_2 (dst, retn);
+      break;
+    case 3:
+      __asm_clear_3 (dst, retn);
+      break;
+  }
+
+  return retn;
+}