* [PATCH v4 0/4] MIPS: Override barrier_before_unreachable() to fix microMIPS
@ 2018-05-11 21:46 James Hogan
2018-05-11 21:47 ` [PATCH v4 3/4] compiler.h: Allow arch-specific overrides James Hogan
0 siblings, 1 reply; 2+ messages in thread
From: James Hogan @ 2018-05-11 21:46 UTC (permalink / raw)
To: linux-mips, Arnd Bergmann, Richard Henderson, Ivan Kokshaysky,
Matt Turner, linux-alpha, Jeff Dike, Richard Weinberger,
user-mode-linux-devel
Cc: James Hogan, Ralf Baechle, Paul Burton, Matthew Fortune,
Robert Suchanek, linux-arch
This series overrides barrier_before_unreachable() for MIPS to add an
.insn assembler directive.
Due to the subsequent __builtin_unreachable(), the assembler can't tell
that a label on the empty inline asm is code rather than data, so any
microMIPS branches targeting it (which sadly can't be removed) raise
errors due to the mismatching ISA mode, Adding the .insn in patch 4
tells the assembler that it should be treated as code.
To do this we add a new standard asm/compiler.h for architecture
overrides in patch 3. There are a few existing asm/compiler.h files
already existing, most of which are fairly simple and don't include
anything else (arm, arm64, mips). Unfortunately the alpha one includes
linux/compiler.h though, so it can undefine some inline macros. On
Arnd's suggestion this is converted to use OPTIMIZE_INLINING instead in
patch 1. A build of alpha's defconfig on GCC 7.3 before and after this
series results in the following size differences, which appear harmless
to me:
$ ./scripts/bloat-o-meter vmlinux.1 vmlinux.2
add/remove: 1/1 grow/shrink: 3/0 up/down: 264/-348 (-84)
Function old new delta
cap_bprm_set_creds 1496 1664 +168
cap_issubset - 68 +68
flex_array_put 328 344 +16
cap_capset 488 500 +12
nonroot_raised_pE.constprop 348 - -348
Total: Before=5823709, After=5823625, chg -0.00%
Also um needs the generated/ include directory adding to the include
paths in patch 2 so that an asm-generic wrapper asm/compiler.h can be
included from automatically included headers.
Changes in v4 (James):
- Fix asm-generic/compiler.h include from check, compiler_types.h is
included on the command line so linux/compiler.h may not be included
(kbuild test robot).
- New patch 2 to fix um (kbuild test robot).
Changes in v3 (James):
- New patch 1.
- Rebase after 4.17 arch removal and update commit messages.
- Use asm/compiler.h instead of compiler-gcc.h (Arnd).
- Drop stable tag for now.
Changes in v2 (Paul):
- Add generic-y entries to arch Kbuild files. Oops!
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Matthew Fortune <matthew.fortune@mips.com>
Cc: Robert Suchanek <robert.suchanek@mips.com>
Cc: linux-alpha@vger.kernel.org
Cc: user-mode-linux-devel@lists.sourceforge.net
Cc: linux-mips@linux-mips.org
Cc: linux-arch@vger.kernel.org
James Hogan (2):
alpha: Use OPTIMIZE_INLINING instead of asm/compiler.h
um: Add generated/ to MODE_INCLUDE
Paul Burton (2):
compiler.h: Allow arch-specific overrides
MIPS: Workaround GCC __builtin_unreachable reordering bug
arch/alpha/Kconfig | 6 ++++++
arch/alpha/include/asm/compiler.h | 11 -----------
arch/arc/include/asm/Kbuild | 1 +
arch/c6x/include/asm/Kbuild | 1 +
arch/h8300/include/asm/Kbuild | 1 +
arch/hexagon/include/asm/Kbuild | 1 +
arch/ia64/include/asm/Kbuild | 1 +
arch/m68k/include/asm/Kbuild | 1 +
arch/microblaze/include/asm/Kbuild | 1 +
arch/mips/include/asm/compiler.h | 23 +++++++++++++++++++++++
arch/nds32/include/asm/Kbuild | 1 +
arch/nios2/include/asm/Kbuild | 1 +
arch/openrisc/include/asm/Kbuild | 1 +
arch/parisc/include/asm/Kbuild | 1 +
arch/powerpc/include/asm/Kbuild | 1 +
arch/riscv/include/asm/Kbuild | 1 +
arch/s390/include/asm/Kbuild | 1 +
arch/sh/include/asm/Kbuild | 1 +
arch/sparc/include/asm/Kbuild | 1 +
arch/um/Makefile | 1 +
arch/um/include/asm/Kbuild | 1 +
arch/unicore32/include/asm/Kbuild | 1 +
arch/x86/include/asm/Kbuild | 1 +
arch/xtensa/include/asm/Kbuild | 1 +
include/asm-generic/compiler.h | 8 ++++++++
include/linux/compiler-gcc.h | 2 ++
include/linux/compiler_types.h | 3 +++
27 files changed, 63 insertions(+), 11 deletions(-)
create mode 100644 include/asm-generic/compiler.h
base-commit: 6d08b06e67cd117f6992c46611dfb4ce267cd71e
--
git-series 0.9.1
^ permalink raw reply [flat|nested] 2+ messages in thread
* [PATCH v4 3/4] compiler.h: Allow arch-specific overrides
2018-05-11 21:46 [PATCH v4 0/4] MIPS: Override barrier_before_unreachable() to fix microMIPS James Hogan
@ 2018-05-11 21:47 ` James Hogan
0 siblings, 0 replies; 2+ messages in thread
From: James Hogan @ 2018-05-11 21:47 UTC (permalink / raw)
To: linux-mips, Arnd Bergmann, Richard Henderson, Ivan Kokshaysky,
Matt Turner, linux-alpha, Jeff Dike, Richard Weinberger,
user-mode-linux-devel
Cc: James Hogan, Paul Burton, Ralf Baechle, linux-arch
From: Paul Burton <paul.burton@mips.com>
Include an arch-specific asm/compiler.h and allow for it to define a
custom version of barrier_before_unreachable(), which is needed to
workaround several issues on the MIPS architecture.
This patch includes an effectively empty asm-generic implementation of
asm/compiler.h for all architectures except alpha, arm, arm64, and mips
(which already have an asm/compiler.h) and leaves the architecture
specifics to a further patch.
Signed-off-by: Paul Burton <paul.burton@mips.com>
[jhogan@kernel.org: Forward port and use asm/compiler.h instead of
asm/compiler-gcc.h]
Signed-off-by: James Hogan <jhogan@kernel.org>
Reviewed-by: Paul Burton <paul.burton@mips.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-arch@vger.kernel.org
Cc: linux-mips@linux-mips.org
---
Changes in v4 (James):
- Fix asm-generic/compiler.h include from check, compiler_types.h is
included on the command line so linux/compiler.h may not be included
(kbuild test robot).
Changes in v3 (James):
- Rebase after 4.17 arch removal.
- Use asm/compiler.h instead of compiler-gcc.h (Arnd).
- Drop stable tag for now.
Changes in v2 (Paul):
- Add generic-y entries to arch Kbuild files. Oops!
---
arch/arc/include/asm/Kbuild | 1 +
arch/c6x/include/asm/Kbuild | 1 +
arch/h8300/include/asm/Kbuild | 1 +
arch/hexagon/include/asm/Kbuild | 1 +
arch/ia64/include/asm/Kbuild | 1 +
arch/m68k/include/asm/Kbuild | 1 +
arch/microblaze/include/asm/Kbuild | 1 +
arch/nds32/include/asm/Kbuild | 1 +
arch/nios2/include/asm/Kbuild | 1 +
arch/openrisc/include/asm/Kbuild | 1 +
arch/parisc/include/asm/Kbuild | 1 +
arch/powerpc/include/asm/Kbuild | 1 +
arch/riscv/include/asm/Kbuild | 1 +
arch/s390/include/asm/Kbuild | 1 +
arch/sh/include/asm/Kbuild | 1 +
arch/sparc/include/asm/Kbuild | 1 +
arch/um/include/asm/Kbuild | 1 +
arch/unicore32/include/asm/Kbuild | 1 +
arch/x86/include/asm/Kbuild | 1 +
arch/xtensa/include/asm/Kbuild | 1 +
include/asm-generic/compiler.h | 8 ++++++++
include/linux/compiler-gcc.h | 2 ++
include/linux/compiler_types.h | 3 +++
23 files changed, 33 insertions(+)
create mode 100644 include/asm-generic/compiler.h
diff --git a/arch/arc/include/asm/Kbuild b/arch/arc/include/asm/Kbuild
index 4bd5d4369e05..61ba443ad252 100644
--- a/arch/arc/include/asm/Kbuild
+++ b/arch/arc/include/asm/Kbuild
@@ -1,5 +1,6 @@
# SPDX-License-Identifier: GPL-2.0
generic-y += bugs.h
+generic-y += compiler.h
generic-y += device.h
generic-y += div64.h
generic-y += emergency-restart.h
diff --git a/arch/c6x/include/asm/Kbuild b/arch/c6x/include/asm/Kbuild
index fd4c840de837..ddfa28f80955 100644
--- a/arch/c6x/include/asm/Kbuild
+++ b/arch/c6x/include/asm/Kbuild
@@ -1,6 +1,7 @@
generic-y += atomic.h
generic-y += barrier.h
generic-y += bugs.h
+generic-y += compiler.h
generic-y += current.h
generic-y += device.h
generic-y += div64.h
diff --git a/arch/h8300/include/asm/Kbuild b/arch/h8300/include/asm/Kbuild
index 14bac06b7116..bf06091a6034 100644
--- a/arch/h8300/include/asm/Kbuild
+++ b/arch/h8300/include/asm/Kbuild
@@ -3,6 +3,7 @@ generic-y += barrier.h
generic-y += bugs.h
generic-y += cacheflush.h
generic-y += checksum.h
+generic-y += compiler.h
generic-y += current.h
generic-y += delay.h
generic-y += device.h
diff --git a/arch/hexagon/include/asm/Kbuild b/arch/hexagon/include/asm/Kbuild
index e9743f689fb8..dccedfd7559e 100644
--- a/arch/hexagon/include/asm/Kbuild
+++ b/arch/hexagon/include/asm/Kbuild
@@ -2,6 +2,7 @@
generic-y += barrier.h
generic-y += bug.h
generic-y += bugs.h
+generic-y += compiler.h
generic-y += current.h
generic-y += device.h
generic-y += div64.h
diff --git a/arch/ia64/include/asm/Kbuild b/arch/ia64/include/asm/Kbuild
index 6dd867873364..886bae7b001f 100644
--- a/arch/ia64/include/asm/Kbuild
+++ b/arch/ia64/include/asm/Kbuild
@@ -1,3 +1,4 @@
+generic-y += compiler.h
generic-y += exec.h
generic-y += irq_work.h
generic-y += mcs_spinlock.h
diff --git a/arch/m68k/include/asm/Kbuild b/arch/m68k/include/asm/Kbuild
index 88a9d27df1ac..089cd9b3c9fd 100644
--- a/arch/m68k/include/asm/Kbuild
+++ b/arch/m68k/include/asm/Kbuild
@@ -1,4 +1,5 @@
generic-y += barrier.h
+generic-y += compiler.h
generic-y += device.h
generic-y += emergency-restart.h
generic-y += exec.h
diff --git a/arch/microblaze/include/asm/Kbuild b/arch/microblaze/include/asm/Kbuild
index 3c80a5a308ed..920ee0afc627 100644
--- a/arch/microblaze/include/asm/Kbuild
+++ b/arch/microblaze/include/asm/Kbuild
@@ -2,6 +2,7 @@ generic-y += barrier.h
generic-y += bitops.h
generic-y += bug.h
generic-y += bugs.h
+generic-y += compiler.h
generic-y += device.h
generic-y += div64.h
generic-y += emergency-restart.h
diff --git a/arch/nds32/include/asm/Kbuild b/arch/nds32/include/asm/Kbuild
index 06bdf8167f5a..5536db1084f4 100644
--- a/arch/nds32/include/asm/Kbuild
+++ b/arch/nds32/include/asm/Kbuild
@@ -9,6 +9,7 @@ generic-y += checksum.h
generic-y += clkdev.h
generic-y += cmpxchg.h
generic-y += cmpxchg-local.h
+generic-y += compiler.h
generic-y += cputime.h
generic-y += device.h
generic-y += div64.h
diff --git a/arch/nios2/include/asm/Kbuild b/arch/nios2/include/asm/Kbuild
index d232da2cbb38..7a351811b525 100644
--- a/arch/nios2/include/asm/Kbuild
+++ b/arch/nios2/include/asm/Kbuild
@@ -4,6 +4,7 @@ generic-y += bitops.h
generic-y += bug.h
generic-y += bugs.h
generic-y += cmpxchg.h
+generic-y += compiler.h
generic-y += current.h
generic-y += device.h
generic-y += div64.h
diff --git a/arch/openrisc/include/asm/Kbuild b/arch/openrisc/include/asm/Kbuild
index f05c722a21f8..809c2e188884 100644
--- a/arch/openrisc/include/asm/Kbuild
+++ b/arch/openrisc/include/asm/Kbuild
@@ -2,6 +2,7 @@ generic-y += barrier.h
generic-y += bug.h
generic-y += bugs.h
generic-y += checksum.h
+generic-y += compiler.h
generic-y += current.h
generic-y += device.h
generic-y += div64.h
diff --git a/arch/parisc/include/asm/Kbuild b/arch/parisc/include/asm/Kbuild
index 2013d639e735..e458cba4f5ae 100644
--- a/arch/parisc/include/asm/Kbuild
+++ b/arch/parisc/include/asm/Kbuild
@@ -1,4 +1,5 @@
generic-y += barrier.h
+generic-y += compiler.h
generic-y += current.h
generic-y += device.h
generic-y += div64.h
diff --git a/arch/powerpc/include/asm/Kbuild b/arch/powerpc/include/asm/Kbuild
index 3196d227e351..636a1dae6adc 100644
--- a/arch/powerpc/include/asm/Kbuild
+++ b/arch/powerpc/include/asm/Kbuild
@@ -1,3 +1,4 @@
+generic-y += compiler.h
generic-y += div64.h
generic-y += export.h
generic-y += irq_regs.h
diff --git a/arch/riscv/include/asm/Kbuild b/arch/riscv/include/asm/Kbuild
index 1e5fd280fb4d..58e8ed54a870 100644
--- a/arch/riscv/include/asm/Kbuild
+++ b/arch/riscv/include/asm/Kbuild
@@ -1,6 +1,7 @@
generic-y += bugs.h
generic-y += cacheflush.h
generic-y += checksum.h
+generic-y += compiler.h
generic-y += cputime.h
generic-y += device.h
generic-y += div64.h
diff --git a/arch/s390/include/asm/Kbuild b/arch/s390/include/asm/Kbuild
index e3239772887a..689993a319d6 100644
--- a/arch/s390/include/asm/Kbuild
+++ b/arch/s390/include/asm/Kbuild
@@ -6,6 +6,7 @@ generated-y += unistd_nr.h
generic-y += asm-offsets.h
generic-y += cacheflush.h
+generic-y += compiler.h
generic-y += device.h
generic-y += dma-contiguous.h
generic-y += dma-mapping.h
diff --git a/arch/sh/include/asm/Kbuild b/arch/sh/include/asm/Kbuild
index 1efcce74997b..3074c98526bc 100644
--- a/arch/sh/include/asm/Kbuild
+++ b/arch/sh/include/asm/Kbuild
@@ -1,3 +1,4 @@
+generic-y += compiler.h
generic-y += current.h
generic-y += delay.h
generic-y += div64.h
diff --git a/arch/sparc/include/asm/Kbuild b/arch/sparc/include/asm/Kbuild
index ac67828da201..d0b551d14ebd 100644
--- a/arch/sparc/include/asm/Kbuild
+++ b/arch/sparc/include/asm/Kbuild
@@ -1,6 +1,7 @@
# User exported sparc header files
+generic-y += compiler.h
generic-y += div64.h
generic-y += emergency-restart.h
generic-y += exec.h
diff --git a/arch/um/include/asm/Kbuild b/arch/um/include/asm/Kbuild
index bb5a196c3061..ccf8a2f5cb08 100644
--- a/arch/um/include/asm/Kbuild
+++ b/arch/um/include/asm/Kbuild
@@ -1,6 +1,7 @@
generic-y += barrier.h
generic-y += bpf_perf_event.h
generic-y += bug.h
+generic-y += compiler.h
generic-y += current.h
generic-y += delay.h
generic-y += device.h
diff --git a/arch/unicore32/include/asm/Kbuild b/arch/unicore32/include/asm/Kbuild
index 6f70c76c81fc..a90a693da5c2 100644
--- a/arch/unicore32/include/asm/Kbuild
+++ b/arch/unicore32/include/asm/Kbuild
@@ -1,5 +1,6 @@
generic-y += atomic.h
generic-y += bugs.h
+generic-y += compiler.h
generic-y += current.h
generic-y += device.h
generic-y += div64.h
diff --git a/arch/x86/include/asm/Kbuild b/arch/x86/include/asm/Kbuild
index de690c2d2e33..de4246599536 100644
--- a/arch/x86/include/asm/Kbuild
+++ b/arch/x86/include/asm/Kbuild
@@ -6,6 +6,7 @@ generated-y += unistd_32_ia32.h
generated-y += unistd_64_x32.h
generated-y += xen-hypercalls.h
+generic-y += compiler.h
generic-y += dma-contiguous.h
generic-y += early_ioremap.h
generic-y += mcs_spinlock.h
diff --git a/arch/xtensa/include/asm/Kbuild b/arch/xtensa/include/asm/Kbuild
index 436b20337168..048341532d48 100644
--- a/arch/xtensa/include/asm/Kbuild
+++ b/arch/xtensa/include/asm/Kbuild
@@ -1,4 +1,5 @@
generic-y += bug.h
+generic-y += compiler.h
generic-y += device.h
generic-y += div64.h
generic-y += dma-contiguous.h
diff --git a/include/asm-generic/compiler.h b/include/asm-generic/compiler.h
new file mode 100644
index 000000000000..081593903904
--- /dev/null
+++ b/include/asm-generic/compiler.h
@@ -0,0 +1,8 @@
+#ifndef __LINUX_COMPILER_TYPES_H
+#error "Please don't include <asm/compiler.h> directly, include <linux/compiler.h> instead."
+#endif
+
+/*
+ * We have nothing architecture-specific to do here, simply leave everything to
+ * the generic linux/compiler.h.
+ */
diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
index b4bf73f5e38f..1f673a28960d 100644
--- a/include/linux/compiler-gcc.h
+++ b/include/linux/compiler-gcc.h
@@ -218,7 +218,9 @@
*
* Adding an empty inline assembly before it works around the problem
*/
+#ifndef barrier_before_unreachable
#define barrier_before_unreachable() asm volatile("")
+#endif
/*
* Mark a position in code as unreachable. This can be used to
diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h
index 6b79a9bba9a7..a20be5fce3c8 100644
--- a/include/linux/compiler_types.h
+++ b/include/linux/compiler_types.h
@@ -54,6 +54,9 @@ extern void __chk_io_ptr(const volatile void __iomem *);
#ifdef __KERNEL__
+/* Allow architectures to override some definitions where necessary */
+#include <asm/compiler.h>
+
#ifdef __GNUC__
#include <linux/compiler-gcc.h>
#endif
--
git-series 0.9.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
end of thread, other threads:[~2018-05-11 21:47 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2018-05-11 21:46 [PATCH v4 0/4] MIPS: Override barrier_before_unreachable() to fix microMIPS James Hogan
2018-05-11 21:47 ` [PATCH v4 3/4] compiler.h: Allow arch-specific overrides James Hogan
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).