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[PULL 32/45] qemu/atomic: Drop special case for unsupported compiler
From: |
Paolo Bonzini |
Subject: |
[PULL 32/45] qemu/atomic: Drop special case for unsupported compiler |
Date: |
Tue, 15 Dec 2020 12:54:32 -0500 |
From: Philippe Mathieu-Daudé <philmd@redhat.com>
Since commit efc6c070aca ("configure: Add a test for the
minimum compiler version") the minimum compiler version
required for GCC is 4.8, which has the GCC BZ#36793 bug fixed.
We can safely remove the special case introduced in commit
a281ebc11a6 ("virtio: add missing mb() on notification").
With clang 3.4, __ATOMIC_RELAXED is defined, so the chunk to
remove (which is x86-specific), isn't reached either.
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20201210134752.780923-2-marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
include/qemu/atomic.h | 17 -----------------
1 file changed, 17 deletions(-)
diff --git a/include/qemu/atomic.h b/include/qemu/atomic.h
index c1d211a351..8f4b3a80fb 100644
--- a/include/qemu/atomic.h
+++ b/include/qemu/atomic.h
@@ -241,23 +241,6 @@
#else /* __ATOMIC_RELAXED */
-/*
- * We use GCC builtin if it's available, as that can use mfence on
- * 32-bit as well, e.g. if built with -march=pentium-m. However, on
- * i386 the spec is buggy, and the implementation followed it until
- * 4.3 (http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36793).
- */
-#if defined(__i386__) || defined(__x86_64__)
-#if !QEMU_GNUC_PREREQ(4, 4)
-#if defined __x86_64__
-#define smp_mb() ({ asm volatile("mfence" ::: "memory"); (void)0; })
-#else
-#define smp_mb() ({ asm volatile("lock; addl $0,0(%%esp) " ::: "memory");
(void)0; })
-#endif
-#endif
-#endif
-
-
#ifdef __alpha__
#define smp_read_barrier_depends() asm volatile("mb":::"memory")
#endif
--
2.26.2
- [PULL 16/45] vl: Add option to avoid stopping VM upon guest panic, (continued)
- [PULL 16/45] vl: Add option to avoid stopping VM upon guest panic, Paolo Bonzini, 2020/12/15
- [PULL 21/45] docs/system: Move the list of removed features to a separate file, Paolo Bonzini, 2020/12/15
- [PULL 07/45] chardev: do not use machine_init_done, Paolo Bonzini, 2020/12/15
- [PULL 17/45] qtest/pvpanic: Test panic option that allows VM to continue, Paolo Bonzini, 2020/12/15
- [PULL 18/45] msix: assert that accesses are within bounds, Paolo Bonzini, 2020/12/15
- [PULL 22/45] Remove the deprecated -realtime option, Paolo Bonzini, 2020/12/15
- [PULL 26/45] kvm: Take into account the unaligned section size when preparing bitmap, Paolo Bonzini, 2020/12/15
- [PULL 25/45] scsi: fix device removal race vs IO restart callback on resume, Paolo Bonzini, 2020/12/15
- [PULL 27/45] qemu-option: simplify search for end of key, Paolo Bonzini, 2020/12/15
- [PULL 36/45] tests: remove GCC < 4 fallbacks, Paolo Bonzini, 2020/12/15
- [PULL 32/45] qemu/atomic: Drop special case for unsupported compiler,
Paolo Bonzini <=
- [PULL 35/45] qemu-plugin.h: remove GCC < 4, Paolo Bonzini, 2020/12/15
- [PULL 42/45] linux-user: remove GNUC check, Paolo Bonzini, 2020/12/15
- [PULL 20/45] accel/tcg: Remove deprecated '-tb-size' option, Paolo Bonzini, 2020/12/15
- [PULL 28/45] qemu-option: pass QemuOptsList to opts_accepts_any, Paolo Bonzini, 2020/12/15
- [PULL 24/45] icount: improve exec nocache usage, Paolo Bonzini, 2020/12/15
- [PULL 29/45] vl: rename local variable in configure_accelerators, Paolo Bonzini, 2020/12/15
- [PULL 31/45] hw/core: Restrict 'fw-path-provider.c' to system mode emulation, Paolo Bonzini, 2020/12/15
- [PULL 33/45] accel/tcg: Remove special case for GCC < 4.6, Paolo Bonzini, 2020/12/15
- [PULL 30/45] docs: set CONFDIR when running sphinx, Paolo Bonzini, 2020/12/15
- [PULL 37/45] virtiofsd: replace _Static_assert with QEMU_BUILD_BUG_ON, Paolo Bonzini, 2020/12/15