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Re: [PATCH, HPPA] Atomic builtins using kernel helpers for Linux
Mark Mitchell wrote:
> Daniel Jacobowitz wrote:
>> On Thu, Jul 10, 2008 at 10:36:13AM -0400, Carlos O'Donell wrote:
>>> Do you think that will get messy?
>>
>> Yes. I also think it's of limited use. Out of line calls make sense
>> for the architectures which need kernel helpers, which on Linux I
>> think is ARM pre-v6K, hppa, and maybe coldfire. Anyone with
>> instructions is going to want to use them inline.
>
> I think that if Julian's patch is OK for ARM, then we should put it in.
> If parts of it can be reused on HPPA, ColdFire, etc., then we can
> refactor at that point.
Below is the equivalent patch for HPPA.
As mentioned before, there are not much differences between this version and
the ARM version.
OK for mainline as well ?
Helge
ChangeLog
gcc/
* config/pa/t-linux (LIB2FUNCS_STATIC_EXTRA): Add
config/pa/linux-atomic.c.
* config/pa/t-linux64 (LIB2FUNCS_STATIC_EXTRA): Add
config/pa/linux-atomic.c.
* config/pa/linux-atomic.c: New.
Index: gcc/config/pa/linux-atomic.c
===================================================================
--- gcc/config/pa/linux-atomic.c (revision 0)
+++ gcc/config/pa/linux-atomic.c (revision 0)
@@ -0,0 +1,299 @@
+/* Linux-specific atomic operations for PA Linux.
+ Copyright (C) 2008 Free Software Foundation, Inc.
+ Based on code contributed by CodeSourcery for ARM EABI Linux.
+ Modifications for PA Linux by Helge Deller <deller@gmx.de>
+
+This file is part of GCC.
+
+GCC 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.
+
+In addition to the permissions in the GNU General Public License, the
+Free Software Foundation gives you unlimited permission to link the
+compiled version of this file into combinations with other programs,
+and to distribute those combinations without any restriction coming
+from the use of this file. (The General Public License restrictions
+do apply in other respects; for example, they cover modification of
+the file, and distribution when not linked into a combine
+executable.)
+
+GCC 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 GCC; see the file COPYING. If not, write to the Free
+Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301, USA. */
+
+/* Determine kernel LWS function call (0=32bit, 1=64bit userspace) */
+#define LWS_CAS (sizeof(unsigned long) == 4 ? 0 : 1)
+
+/* Kernel helper for compare-and-exchange. */
+#define __kernel_cmpxchg( oldval, newval, mem ) \
+ ({ \
+ register long lws_ret asm("r28"); \
+ register long lws_errno asm("r21"); \
+ register unsigned long lws_mem asm("r26") = (unsigned long) (mem); \
+ register long lws_old asm("r25") = (oldval); \
+ register long lws_new asm("r24") = (newval); \
+ asm volatile( "ble 0xb0(%%sr2, %%r0) \n\t" \
+ "ldi %5, %%r20 \n\t" \
+ : "=r" (lws_ret), "=r" (lws_errno), "=r" (lws_mem), \
+ "=r" (lws_old), "=r" (lws_new) \
+ : "i" (LWS_CAS), "2" (lws_mem), "3" (lws_old), "4" (lws_new) \
+ : "r1", "r20", "r22", "r23", "r31", "memory" \
+ ); \
+ lws_errno; \
+ })
+
+/* Kernel helper for memory barrier. */
+#define __kernel_dmb() asm volatile ( "" : : : "memory" );
+
+/* Note: we implement byte, short and int versions of atomic operations
using
+ the above kernel helpers, but there is no support for "long long"
(64-bit)
+ operations as yet. */
+
+#define HIDDEN __attribute__ ((visibility ("hidden")))
+
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+#define INVERT_MASK_1 0
+#define INVERT_MASK_2 0
+#elif __BYTE_ORDER == __BIG_ENDIAN
+#define INVERT_MASK_1 24
+#define INVERT_MASK_2 16
+#else
+#error "Endianess missing"
+#endif
+
+#define MASK_1 0xffu
+#define MASK_2 0xffffu
+
+#define FETCH_AND_OP_WORD(OP, PFX_OP, INF_OP) \
+ int HIDDEN \
+ __sync_fetch_and_##OP##_4 (int *ptr, int val) \
+ { \
+ int failure, tmp; \
+ \
+ do { \
+ tmp = *ptr; \
+ failure = __kernel_cmpxchg (tmp, PFX_OP tmp INF_OP val, ptr); \
+ } while (failure != 0); \
+ \
+ return tmp; \
+ }
+
+FETCH_AND_OP_WORD (add, , +)
+FETCH_AND_OP_WORD (sub, , -)
+FETCH_AND_OP_WORD (or, , |)
+FETCH_AND_OP_WORD (and, , &)
+FETCH_AND_OP_WORD (xor, , ^)
+FETCH_AND_OP_WORD (nand, ~, &)
+
+#define NAME_oldval(OP, WIDTH) __sync_fetch_and_##OP##_##WIDTH
+#define NAME_newval(OP, WIDTH) __sync_##OP##_and_fetch_##WIDTH
+
+/* Implement both __sync_<op>_and_fetch and __sync_fetch_and_<op> for
+ subword-sized quantities. */
+
+#define SUBWORD_SYNC_OP(OP, PFX_OP, INF_OP, TYPE, WIDTH, RETURN) \
+ TYPE HIDDEN \
+ NAME##_##RETURN (OP, WIDTH) (TYPE *ptr, TYPE val) \
+ { \
+ int *wordptr = (int *) ((unsigned int) ptr & ~3); \
+ unsigned int mask, shift, oldval, newval; \
+ int failure; \
+ \
+ shift = (((unsigned int) ptr & 3) << 3) ^ INVERT_MASK_##WIDTH; \
+ mask = MASK_##WIDTH << shift; \
+ \
+ do { \
+ oldval = *wordptr; \
+ newval = ((PFX_OP ((oldval & mask) >> shift) \
+ INF_OP (unsigned int) val) << shift) & mask; \
+ newval |= oldval & ~mask; \
+ failure = __kernel_cmpxchg (oldval, newval, wordptr); \
+ } while (failure != 0); \
+ \
+ return (RETURN & mask) >> shift; \
+ }
+
+SUBWORD_SYNC_OP (add, , +, short, 2, oldval)
+SUBWORD_SYNC_OP (sub, , -, short, 2, oldval)
+SUBWORD_SYNC_OP (or, , |, short, 2, oldval)
+SUBWORD_SYNC_OP (and, , &, short, 2, oldval)
+SUBWORD_SYNC_OP (xor, , ^, short, 2, oldval)
+SUBWORD_SYNC_OP (nand, ~, &, short, 2, oldval)
+
+SUBWORD_SYNC_OP (add, , +, char, 1, oldval)
+SUBWORD_SYNC_OP (sub, , -, char, 1, oldval)
+SUBWORD_SYNC_OP (or, , |, char, 1, oldval)
+SUBWORD_SYNC_OP (and, , &, char, 1, oldval)
+SUBWORD_SYNC_OP (xor, , ^, char, 1, oldval)
+SUBWORD_SYNC_OP (nand, ~, &, char, 1, oldval)
+
+#define OP_AND_FETCH_WORD(OP, PFX_OP, INF_OP) \
+ int HIDDEN \
+ __sync_##OP##_and_fetch_4 (int *ptr, int val) \
+ { \
+ int tmp, failure; \
+ \
+ do { \
+ tmp = *ptr; \
+ failure = __kernel_cmpxchg (tmp, PFX_OP tmp INF_OP val, ptr); \
+ } while (failure != 0); \
+ \
+ return PFX_OP tmp INF_OP val; \
+ }
+
+OP_AND_FETCH_WORD (add, , +)
+OP_AND_FETCH_WORD (sub, , -)
+OP_AND_FETCH_WORD (or, , |)
+OP_AND_FETCH_WORD (and, , &)
+OP_AND_FETCH_WORD (xor, , ^)
+OP_AND_FETCH_WORD (nand, ~, &)
+
+SUBWORD_SYNC_OP (add, , +, short, 2, newval)
+SUBWORD_SYNC_OP (sub, , -, short, 2, newval)
+SUBWORD_SYNC_OP (or, , |, short, 2, newval)
+SUBWORD_SYNC_OP (and, , &, short, 2, newval)
+SUBWORD_SYNC_OP (xor, , ^, short, 2, newval)
+SUBWORD_SYNC_OP (nand, ~, &, short, 2, newval)
+
+SUBWORD_SYNC_OP (add, , +, char, 1, newval)
+SUBWORD_SYNC_OP (sub, , -, char, 1, newval)
+SUBWORD_SYNC_OP (or, , |, char, 1, newval)
+SUBWORD_SYNC_OP (and, , &, char, 1, newval)
+SUBWORD_SYNC_OP (xor, , ^, char, 1, newval)
+SUBWORD_SYNC_OP (nand, ~, &, char, 1, newval)
+
+int HIDDEN
+__sync_val_compare_and_swap_4 (int *ptr, int oldval, int newval)
+{
+ int actual_oldval, fail;
+
+ while (1)
+ {
+ actual_oldval = *ptr;
+
+ if (oldval != actual_oldval)
+ return actual_oldval;
+
+ fail = __kernel_cmpxchg (actual_oldval, newval, ptr);
+
+ if (!fail)
+ return oldval;
+ }
+}
+
+#define SUBWORD_VAL_CAS(TYPE, WIDTH) \
+ TYPE HIDDEN \
+ __sync_val_compare_and_swap_##WIDTH (TYPE *ptr, TYPE oldval, \
+ TYPE newval) \
+ { \
+ int *wordptr = (int *)((unsigned int) ptr & ~3), fail; \
+ unsigned int mask, shift, actual_oldval, actual_newval; \
+ \
+ shift = (((unsigned int) ptr & 3) << 3) ^ INVERT_MASK_##WIDTH; \
+ mask = MASK_##WIDTH << shift; \
+ \
+ while (1) \
+ { \
+ actual_oldval = *wordptr; \
+ \
+ if (((actual_oldval & mask) >> shift) != (unsigned int) oldval) \
+ return (actual_oldval & mask) >> shift; \
+ \
+ actual_newval = (actual_oldval & ~mask) \
+ | (((unsigned int) newval << shift) & mask); \
+ \
+ fail = __kernel_cmpxchg (actual_oldval, actual_newval, \
+ wordptr); \
+ \
+ if (!fail) \
+ return oldval; \
+ } \
+ }
+
+SUBWORD_VAL_CAS (short, 2)
+SUBWORD_VAL_CAS (char, 1)
+
+typedef unsigned char bool;
+
+bool HIDDEN
+__sync_bool_compare_and_swap_4 (int *ptr, int oldval, int newval)
+{
+ int failure = __kernel_cmpxchg (oldval, newval, ptr);
+ return (failure == 0);
+}
+
+#define SUBWORD_BOOL_CAS(TYPE, WIDTH) \
+ bool HIDDEN \
+ __sync_bool_compare_and_swap_##WIDTH (TYPE *ptr, TYPE oldval, \
+ TYPE newval) \
+ { \
+ TYPE actual_oldval \
+ = __sync_val_compare_and_swap_##WIDTH (ptr, oldval, newval); \
+ return (oldval == actual_oldval); \
+ }
+
+SUBWORD_BOOL_CAS (short, 2)
+SUBWORD_BOOL_CAS (char, 1)
+
+void HIDDEN
+__sync_synchronize (void)
+{
+ __kernel_dmb ();
+}
+
+int HIDDEN
+__sync_lock_test_and_set_4 (int *ptr, int val)
+{
+ int failure, oldval;
+
+ do {
+ oldval = *ptr;
+ failure = __kernel_cmpxchg (oldval, val, ptr);
+ } while (failure != 0);
+
+ return oldval;
+}
+
+#define SUBWORD_TEST_AND_SET(TYPE, WIDTH) \
+ TYPE HIDDEN \
+ __sync_lock_test_and_set_##WIDTH (TYPE *ptr, TYPE val) \
+ { \
+ int failure; \
+ unsigned int oldval, newval, shift, mask; \
+ int *wordptr = (int *) ((unsigned int) ptr & ~3); \
+ \
+ shift = (((unsigned int) ptr & 3) << 3) ^ INVERT_MASK_##WIDTH; \
+ mask = MASK_##WIDTH << shift; \
+ \
+ do { \
+ oldval = *wordptr; \
+ newval = (oldval & ~mask) \
+ | (((unsigned int) val << shift) & mask); \
+ failure = __kernel_cmpxchg (oldval, newval, wordptr); \
+ } while (failure != 0); \
+ \
+ return (oldval & mask) >> shift; \
+ }
+
+SUBWORD_TEST_AND_SET (short, 2)
+SUBWORD_TEST_AND_SET (char, 1)
+
+#define SYNC_LOCK_RELEASE(TYPE, WIDTH) \
+ void HIDDEN \
+ __sync_lock_release_##WIDTH (TYPE *ptr) \
+ { \
+ *ptr = 0; \
+ __kernel_dmb (); \
+ }
+
+SYNC_LOCK_RELEASE (int, 4)
+SYNC_LOCK_RELEASE (short, 2)
+SYNC_LOCK_RELEASE (char, 1)
Index: gcc/config/pa/t-linux64
===================================================================
--- gcc/config/pa/t-linux64 (revision 137753)
+++ gcc/config/pa/t-linux64 (working copy)
@@ -8,5 +8,7 @@
# Actually, hppa64 is always PIC but adding -fPIC does no harm.
CRTSTUFF_T_CFLAGS_S = -fPIC
+LIB2FUNCS_STATIC_EXTRA = $(srcdir)/config/pa/linux-atomic.c
+
# Compile libgcc2.a as PIC.
TARGET_LIBGCC2_CFLAGS = -fPIC -Dpa64=1 -DELF=1
Index: gcc/config/pa/t-linux
===================================================================
--- gcc/config/pa/t-linux (revision 137753)
+++ gcc/config/pa/t-linux (working copy)
@@ -9,6 +9,7 @@
TARGET_LIBGCC2_CFLAGS = -fPIC -DELF=1 -DLINUX=1
LIB2FUNCS_EXTRA=fptr.c
+LIB2FUNCS_STATIC_EXTRA = $(srcdir)/config/pa/linux-atomic.c
fptr.c: $(srcdir)/config/pa/fptr.c
rm -f fptr.c