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Revert "x86/refcount: Work around GCC inlining bug"
This reverts commit9e1725b410. See this commit for details about the revert:e769742d35("Revert "x86/jump-labels: Macrofy inline assembly code to work around GCC inlining bugs"") The conflict resolution for interaction with: 288e4521f0f6: ("x86/asm: 'Simplify' GEN_*_RMWcc() macros") was provided by Masahiro Yamada. Conflicts: arch/x86/include/asm/refcount.h Reported-by: Masahiro Yamada <yamada.masahiro@socionext.com> Reviewed-by: Borislav Petkov <bp@alien8.de> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Juergen Gross <jgross@suse.com> Cc: Richard Biener <rguenther@suse.de> Cc: Kees Cook <keescook@chromium.org> Cc: Segher Boessenkool <segher@kernel.crashing.org> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Nadav Amit <namit@vmware.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Ingo Molnar
parent
851a4cd7cc
commit
ac180540b0
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@ -4,41 +4,6 @@
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* x86-specific implementation of refcount_t. Based on PAX_REFCOUNT from
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* PaX/grsecurity.
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*/
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#ifdef __ASSEMBLY__
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#include <asm/asm.h>
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#include <asm/bug.h>
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.macro REFCOUNT_EXCEPTION counter:req
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.pushsection .text..refcount
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111: lea \counter, %_ASM_CX
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112: ud2
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ASM_UNREACHABLE
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.popsection
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113: _ASM_EXTABLE_REFCOUNT(112b, 113b)
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.endm
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/* Trigger refcount exception if refcount result is negative. */
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.macro REFCOUNT_CHECK_LT_ZERO counter:req
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js 111f
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REFCOUNT_EXCEPTION counter="\counter"
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.endm
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/* Trigger refcount exception if refcount result is zero or negative. */
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.macro REFCOUNT_CHECK_LE_ZERO counter:req
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jz 111f
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REFCOUNT_CHECK_LT_ZERO counter="\counter"
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.endm
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/* Trigger refcount exception unconditionally. */
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.macro REFCOUNT_ERROR counter:req
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jmp 111f
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REFCOUNT_EXCEPTION counter="\counter"
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.endm
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#else /* __ASSEMBLY__ */
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#include <linux/refcount.h>
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#include <asm/bug.h>
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@ -50,12 +15,35 @@
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* central refcount exception. The fixup address for the exception points
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* back to the regular execution flow in .text.
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*/
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#define _REFCOUNT_EXCEPTION \
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".pushsection .text..refcount\n" \
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"111:\tlea %[var], %%" _ASM_CX "\n" \
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"112:\t" ASM_UD2 "\n" \
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ASM_UNREACHABLE \
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".popsection\n" \
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"113:\n" \
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_ASM_EXTABLE_REFCOUNT(112b, 113b)
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/* Trigger refcount exception if refcount result is negative. */
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#define REFCOUNT_CHECK_LT_ZERO \
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"js 111f\n\t" \
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_REFCOUNT_EXCEPTION
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/* Trigger refcount exception if refcount result is zero or negative. */
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#define REFCOUNT_CHECK_LE_ZERO \
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"jz 111f\n\t" \
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REFCOUNT_CHECK_LT_ZERO
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/* Trigger refcount exception unconditionally. */
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#define REFCOUNT_ERROR \
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"jmp 111f\n\t" \
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_REFCOUNT_EXCEPTION
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static __always_inline void refcount_add(unsigned int i, refcount_t *r)
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{
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asm volatile(LOCK_PREFIX "addl %1,%0\n\t"
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"REFCOUNT_CHECK_LT_ZERO counter=\"%[counter]\""
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: [counter] "+m" (r->refs.counter)
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REFCOUNT_CHECK_LT_ZERO
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: [var] "+m" (r->refs.counter)
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: "ir" (i)
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: "cc", "cx");
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}
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@ -63,32 +51,31 @@ static __always_inline void refcount_add(unsigned int i, refcount_t *r)
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static __always_inline void refcount_inc(refcount_t *r)
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{
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asm volatile(LOCK_PREFIX "incl %0\n\t"
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"REFCOUNT_CHECK_LT_ZERO counter=\"%[counter]\""
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: [counter] "+m" (r->refs.counter)
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REFCOUNT_CHECK_LT_ZERO
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: [var] "+m" (r->refs.counter)
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: : "cc", "cx");
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}
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static __always_inline void refcount_dec(refcount_t *r)
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{
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asm volatile(LOCK_PREFIX "decl %0\n\t"
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"REFCOUNT_CHECK_LE_ZERO counter=\"%[counter]\""
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: [counter] "+m" (r->refs.counter)
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REFCOUNT_CHECK_LE_ZERO
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: [var] "+m" (r->refs.counter)
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: : "cc", "cx");
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}
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static __always_inline __must_check
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bool refcount_sub_and_test(unsigned int i, refcount_t *r)
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{
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return GEN_BINARY_SUFFIXED_RMWcc(LOCK_PREFIX "subl",
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"REFCOUNT_CHECK_LT_ZERO counter=\"%[var]\"",
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REFCOUNT_CHECK_LT_ZERO,
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r->refs.counter, e, "er", i, "cx");
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}
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static __always_inline __must_check bool refcount_dec_and_test(refcount_t *r)
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{
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return GEN_UNARY_SUFFIXED_RMWcc(LOCK_PREFIX "decl",
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"REFCOUNT_CHECK_LT_ZERO counter=\"%[var]\"",
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REFCOUNT_CHECK_LT_ZERO,
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r->refs.counter, e, "cx");
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}
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@ -106,8 +93,8 @@ bool refcount_add_not_zero(unsigned int i, refcount_t *r)
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/* Did we try to increment from/to an undesirable state? */
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if (unlikely(c < 0 || c == INT_MAX || result < c)) {
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asm volatile("REFCOUNT_ERROR counter=\"%[counter]\""
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: : [counter] "m" (r->refs.counter)
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asm volatile(REFCOUNT_ERROR
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: : [var] "m" (r->refs.counter)
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: "cc", "cx");
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break;
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}
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@ -122,6 +109,4 @@ static __always_inline __must_check bool refcount_inc_not_zero(refcount_t *r)
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return refcount_add_not_zero(1, r);
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}
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#endif /* __ASSEMBLY__ */
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#endif
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@ -7,4 +7,3 @@
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*/
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#include <linux/compiler.h>
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#include <asm/refcount.h>
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