1) Is it worth doing some sort of call table?
2) We want to validate ptr (and ptr2 in the SWAP case).
This should probably be done before IRQs are disabled to handle page
faults and whatnot. I'm open for ideas how to implement this.
---
arch/openrisc/kernel/entry.S | 165 ++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 162 insertions(+), 3 deletions(-)
diff --git a/arch/openrisc/kernel/entry.S b/arch/openrisc/kernel/entry.S
index e20c8dd..eb170d0 100644
--- a/arch/openrisc/kernel/entry.S
+++ b/arch/openrisc/kernel/entry.S
@@ -1112,16 +1112,88 @@ ENTRY(sys_rt_sigreturn)
* the atomic in question. Currently, this function implements the
* following variants:
*
- * XCHG:
+ * SWAP:
* @flag: 1
* @ptr1:
* @ptr2:
- * Atomically exchange the values in pointers 1 and 2.
+ * Atomically swap the values in pointers 1 and 2.
+ *
+ * CMPXCHG:
+ * @flag: 2
+ * @ptr: mem
+ * @val1: old
+ * @val2: new
+ * Writes new to *mem if *mem == old. Returns old *mem.
+ *
+ * XCHG:
+ * @flag: 3
+ * @ptr: mem
+ * @val1: new
+ * Store NEW in *MEM and return the old value.
+ *
+ * ADD:
+ * @flag: 4
+ * @ptr: mem
+ * @val1: val
+ * Add VAL to *MEM and return the old value of *MEM.
+ *
+ * DECPOS:
+ * @flag: 5
+ * @ptr: mem
+ * Decrement *MEM if it is > 0, and return the old value.
+ *
+ * AND:
+ * @flag: 6
+ * @ptr: mem
+ * @val1: mask
+ * Atomically *mem &= mask and return the old value of *mem.
+ *
+ * OR:
+ * @flag: 7
+ * @ptr: mem
+ * @val1: mask
+ * Atomically *mem |= mask and return the old value of *mem.
+ *
+ * UMAX: unsigned
+ * @flag: 8
+ * @ptr: mem
+ * @val1: val
+ * If *mem < val, set *mem = max. Returns old value of *mem.
+ *
+ * UMIN: unsigned
+ * @flag: 9
+ * @ptr: mem
+ * @val1: mask
+ * If *mem > val, set *mem = max. Returns old value of *mem.
*
*/
ENTRY(sys_or1k_atomic)
- /* FIXME: This ignores r3 and always does an XCHG */
+ /* TODO: validate mem ptr(s) */
+ /* TODO: use some kind of jmp table? */
+ l.sfeqi r3,1
+ l.bf _atomic_swap
+ l.sfeqi r3,2
+ l.bf _atomic_cmpxchg
+ l.sfeqi r3,3
+ l.bf _atomic_xchg
+ l.sfeqi r3,4
+ l.bf _atomic_add
+ l.sfeqi r3,5
+ l.bf _atomic_decpos
+ l.sfeqi r3,6
+ l.bf _atomic_and
+ l.sfeqi r3,7
+ l.bf _atomic_or
+ l.sfeqi r3,8
+ l.bf _atomic_and
+ l.sfeqi r3,9
+ l.nop
+
+ l.jr r9
+ l.ori r11,r0,-EINVAL
+
+_atomic_swap:
DISABLE_INTERRUPTS(r17,r19)
l.lwz r29,0(r4)
l.lwz r27,0(r5)
@@ -1131,4 +1203,91 @@ ENTRY(sys_or1k_atomic)
l.jr r9
l.or r11,r0,r0
+_atomic_cmpxchg:
+ DISABLE_INTERRUPTS(r17,r19)
+ l.lwz r29,0(r4)
+ l.sfeq r29,r5
+ l.bnf _atomic_cmpxchg_done
+ l.nop
+
+ l.sw 0(r4),r6
+_atomic_cmpxchg_done:
+ ENABLE_INTERRUPTS(r17)
+ l.jr r9
+ l.or r11,r29,r0
+
+_atomic_xchg:
+ DISABLE_INTERRUPTS(r17,r19)
+ l.lwz r29,0(r4)
+ l.sw 0(r4),r5
+ ENABLE_INTERRUPTS(r17)
+ l.jr r9
+ l.or r11,r29,r0
+
+_atomic_add:
+ DISABLE_INTERRUPTS(r17,r19)
+ l.lwz r29,0(r4)
+ l.add r27,r29,r5
+ l.sw 0(r4),r27
+ ENABLE_INTERRUPTS(r17)
+ l.jr r9
+ l.or r11,r29,r0
+
+_atomic_decpos:
+ DISABLE_INTERRUPTS(r17,r19)
+ l.lwz r29,0(r4)
+ l.sfgtsi r29,0
+ l.bnf _atomic_decpos_done
+ l.addi r27,r29,-1
+
+ l.sw 0(r4),r27
+_atomic_decpos_done:
+ ENABLE_INTERRUPTS(r17)
+ l.jr r9
+ l.or r11,r29,r0
+
+_atomic_and:
+ DISABLE_INTERRUPTS(r17,r19)
+ l.lwz r29,0(r4)
+ l.and r27,r29,r5
+ l.sw 0(r4),r27
+ ENABLE_INTERRUPTS(r17)
+ l.jr r9
+ l.or r11,r29,r0
+
+_atomic_or:
+ DISABLE_INTERRUPTS(r17,r19)
+ l.lwz r29,0(r4)
+ l.or r27,r29,r5
+ l.sw 0(r4),r27
+ ENABLE_INTERRUPTS(r17)
+ l.jr r9
+ l.or r11,r29,r0
+
+_atomic_max:
+ DISABLE_INTERRUPTS(r17,r19)
+ l.lwz r29,0(r4)
+ l.sfltu r29,r5
+ l.bnf _atomic_max_done
+ l.nop
+
+ l.sw 0(r4),r5
+_atomic_max_done:
+ ENABLE_INTERRUPTS(r17)
+ l.jr r9
+ l.or r11,r29,r0
+
+_atomic_min:
+ DISABLE_INTERRUPTS(r17,r19)
+ l.lwz r29,0(r4)
+ l.sfgtu r29,r5
+ l.bnf _atomic_min_done
+ l.nop
+
+ l.sw 0(r4),r5
+_atomic_min_done:
+ ENABLE_INTERRUPTS(r17)
+ l.jr r9
+ l.or r11,r29,r0
+
/* ============================================================[ EOF ]=== */
--
1.8.1.2
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