summaryrefslogtreecommitdiff
path: root/arch/x86/include/asm/refcount.h
diff options
context:
space:
mode:
Diffstat (limited to 'arch/x86/include/asm/refcount.h')
-rw-r--r--arch/x86/include/asm/refcount.h126
1 files changed, 0 insertions, 126 deletions
diff --git a/arch/x86/include/asm/refcount.h b/arch/x86/include/asm/refcount.h
deleted file mode 100644
index 232f856e0db0..000000000000
--- a/arch/x86/include/asm/refcount.h
+++ /dev/null
@@ -1,126 +0,0 @@
-#ifndef __ASM_X86_REFCOUNT_H
-#define __ASM_X86_REFCOUNT_H
-/*
- * x86-specific implementation of refcount_t. Based on PAX_REFCOUNT from
- * PaX/grsecurity.
- */
-#include <linux/refcount.h>
-#include <asm/bug.h>
-
-/*
- * This is the first portion of the refcount error handling, which lives in
- * .text.unlikely, and is jumped to from the CPU flag check (in the
- * following macros). This saves the refcount value location into CX for
- * the exception handler to use (in mm/extable.c), and then triggers the
- * central refcount exception. The fixup address for the exception points
- * back to the regular execution flow in .text.
- */
-#define _REFCOUNT_EXCEPTION \
- ".pushsection .text..refcount\n" \
- "111:\tlea %[var], %%" _ASM_CX "\n" \
- "112:\t" ASM_UD2 "\n" \
- ASM_UNREACHABLE \
- ".popsection\n" \
- "113:\n" \
- _ASM_EXTABLE_REFCOUNT(112b, 113b)
-
-/* Trigger refcount exception if refcount result is negative. */
-#define REFCOUNT_CHECK_LT_ZERO \
- "js 111f\n\t" \
- _REFCOUNT_EXCEPTION
-
-/* Trigger refcount exception if refcount result is zero or negative. */
-#define REFCOUNT_CHECK_LE_ZERO \
- "jz 111f\n\t" \
- REFCOUNT_CHECK_LT_ZERO
-
-/* Trigger refcount exception unconditionally. */
-#define REFCOUNT_ERROR \
- "jmp 111f\n\t" \
- _REFCOUNT_EXCEPTION
-
-static __always_inline void refcount_add(unsigned int i, refcount_t *r)
-{
- asm volatile(LOCK_PREFIX "addl %1,%0\n\t"
- REFCOUNT_CHECK_LT_ZERO
- : [var] "+m" (r->refs.counter)
- : "ir" (i)
- : "cc", "cx");
-}
-
-static __always_inline void refcount_inc(refcount_t *r)
-{
- asm volatile(LOCK_PREFIX "incl %0\n\t"
- REFCOUNT_CHECK_LT_ZERO
- : [var] "+m" (r->refs.counter)
- : : "cc", "cx");
-}
-
-static __always_inline void refcount_dec(refcount_t *r)
-{
- asm volatile(LOCK_PREFIX "decl %0\n\t"
- REFCOUNT_CHECK_LE_ZERO
- : [var] "+m" (r->refs.counter)
- : : "cc", "cx");
-}
-
-static __always_inline __must_check
-bool refcount_sub_and_test(unsigned int i, refcount_t *r)
-{
- bool ret = GEN_BINARY_SUFFIXED_RMWcc(LOCK_PREFIX "subl",
- REFCOUNT_CHECK_LT_ZERO,
- r->refs.counter, e, "er", i, "cx");
-
- if (ret) {
- smp_acquire__after_ctrl_dep();
- return true;
- }
-
- return false;
-}
-
-static __always_inline __must_check bool refcount_dec_and_test(refcount_t *r)
-{
- bool ret = GEN_UNARY_SUFFIXED_RMWcc(LOCK_PREFIX "decl",
- REFCOUNT_CHECK_LT_ZERO,
- r->refs.counter, e, "cx");
-
- if (ret) {
- smp_acquire__after_ctrl_dep();
- return true;
- }
-
- return false;
-}
-
-static __always_inline __must_check
-bool refcount_add_not_zero(unsigned int i, refcount_t *r)
-{
- int c, result;
-
- c = atomic_read(&(r->refs));
- do {
- if (unlikely(c == 0))
- return false;
-
- result = c + i;
-
- /* Did we try to increment from/to an undesirable state? */
- if (unlikely(c < 0 || c == INT_MAX || result < c)) {
- asm volatile(REFCOUNT_ERROR
- : : [var] "m" (r->refs.counter)
- : "cc", "cx");
- break;
- }
-
- } while (!atomic_try_cmpxchg(&(r->refs), &c, result));
-
- return c != 0;
-}
-
-static __always_inline __must_check bool refcount_inc_not_zero(refcount_t *r)
-{
- return refcount_add_not_zero(1, r);
-}
-
-#endif