Linux-2.6.12-rc2v2.6.12-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!

1 files changed, 113 insertions, 0 deletions

diff --git a/arch/alpha/lib/clear_user.S b/arch/alpha/lib/clear_user.S
new file mode 100644
index 000000000000..8860316c1957
--- /dev/null
+++ b/arch/alpha/lib/clear_user.S
@@ -0,0 +1,113 @@
+/*
+ * arch/alpha/lib/clear_user.S
+ * Contributed by Richard Henderson <rth@tamu.edu>
+ *
+ * Zero user space, handling exceptions as we go.
+ *
+ * We have to make sure that $0 is always up-to-date and contains the
+ * right "bytes left to zero" value (and that it is updated only _after_
+ * a successful copy).  There is also some rather minor exception setup
+ * stuff.
+ *
+ * NOTE! This is not directly C-callable, because the calling semantics
+ * are different:
+ *
+ * Inputs:
+ *      length in $0
+ *      destination address in $6
+ *      exception pointer in $7
+ *      return address in $28 (exceptions expect it there)
+ *
+ * Outputs:
+ *      bytes left to copy in $0
+ *
+ * Clobbers:
+ *      $1,$2,$3,$4,$5,$6
+ */
+
+/* Allow an exception for an insn; exit if we get one.  */
+#define EX(x,y...)                      \
+        99: x,##y;                      \
+        .section __ex_table,"a";        \
+        .long 99b - .;                  \
+        lda $31, $exception-99b($31);   \
+        .previous
+
+        .set noat
+        .set noreorder
+        .align 4
+
+        .globl __do_clear_user
+        .ent __do_clear_user
+        .frame  $30, 0, $28
+        .prologue 0
+
+$loop:
+        and     $1, 3, $4       # e0    :
+        beq     $4, 1f          # .. e1 :
+
+0:      EX( stq_u $31, 0($6) )  # e0    : zero one word
+        subq    $0, 8, $0       # .. e1 :
+        subq    $4, 1, $4       # e0    :
+        addq    $6, 8, $6       # .. e1 :
+        bne     $4, 0b          # e1    :
+        unop                    #       :
+
+1:      bic     $1, 3, $1       # e0    :
+        beq     $1, $tail       # .. e1 :
+
+2:      EX( stq_u $31, 0($6) )  # e0    : zero four words
+        subq    $0, 8, $0       # .. e1 :
+        EX( stq_u $31, 8($6) )  # e0    :
+        subq    $0, 8, $0       # .. e1 :
+        EX( stq_u $31, 16($6) ) # e0    :
+        subq    $0, 8, $0       # .. e1 :
+        EX( stq_u $31, 24($6) ) # e0    :
+        subq    $0, 8, $0       # .. e1 :
+        subq    $1, 4, $1       # e0    :
+        addq    $6, 32, $6      # .. e1 :
+        bne     $1, 2b          # e1    :
+
+$tail:
+        bne     $2, 1f          # e1    : is there a tail to do?
+        ret     $31, ($28), 1   # .. e1 :
+
+1:      EX( ldq_u $5, 0($6) )   # e0    :
+        clr     $0              # .. e1 :
+        nop                     # e1    :
+        mskqh   $5, $0, $5      # e0    :
+        EX( stq_u $5, 0($6) )   # e0    :
+        ret     $31, ($28), 1   # .. e1 :
+
+__do_clear_user:
+        and     $6, 7, $4       # e0    : find dest misalignment
+        beq     $0, $zerolength # .. e1 :
+        addq    $0, $4, $1      # e0    : bias counter
+        and     $1, 7, $2       # e1    : number of bytes in tail
+        srl     $1, 3, $1       # e0    :
+        beq     $4, $loop       # .. e1 :
+
+        EX( ldq_u $5, 0($6) )   # e0    : load dst word to mask back in
+        beq     $1, $oneword    # .. e1 : sub-word store?
+
+        mskql   $5, $6, $5      # e0    : take care of misaligned head
+        addq    $6, 8, $6       # .. e1 :
+        EX( stq_u $5, -8($6) )  # e0    :
+        addq    $0, $4, $0      # .. e1 : bytes left -= 8 - misalignment
+        subq    $1, 1, $1       # e0    :
+        subq    $0, 8, $0       # .. e1 :
+        br      $loop           # e1    :
+        unop                    #       :
+
+$oneword:
+        mskql   $5, $6, $4      # e0    :
+        mskqh   $5, $2, $5      # e0    :
+        or      $5, $4, $5      # e1    :
+        EX( stq_u $5, 0($6) )   # e0    :
+        clr     $0              # .. e1 :
+
+$zerolength:
+$exception:
+        ret     $31, ($28), 1   # .. e1 :
+
+        .end __do_clear_user