With recent changes in Kconfig processing it is now possible to expose
dependency on specific tools and supported options via Kconfig rather
than bury it deep in Makefile.
This small series try to address the case where the whole feature, for
instance arm64/lse or arm/crypto, depends on GAS.
Vladimir Murzin (4):
kconfig: add as-instr macro to scripts/Kconfig.include
arm64: lse: expose dependency on gas via Kconfig
arm64: turn "broken gas inst" into real config option
ARM: crypto: expose dependency on gas via Kconfig
arch/arm/crypto/Kconfig | 31 +++++++++++++++++++++----------
arch/arm/crypto/Makefile | 31 ++++++-------------------------
arch/arm64/Kconfig | 4 ++++
arch/arm64/Makefile | 18 ++----------------
arch/arm64/include/asm/atomic.h | 2 +-
arch/arm64/include/asm/lse.h | 6 +++---
arch/arm64/kernel/cpufeature.c | 4 ++--
scripts/Kconfig.include | 4 ++++
8 files changed, 43 insertions(+), 57 deletions(-)
--
1.9.1
On 07/11/18 14:55, Will Deacon wrote:
> On Wed, Nov 07, 2018 at 09:40:05AM +0000, Vladimir Murzin wrote:
>> There are cases where the whole feature, for instance arm64/lse or
>> arm/crypto, can depend on assembler. Current practice is to report
>> buildtime that selected feature is not supported, which can be quite
>> annoying...
>
> Why is it annoying? You still end up with a working kernel.
.config doesn't really represent if option was built or not, annoying
part is digging build logs (if anyone's saved them at all!) or relevant
parts of dmesg (if option throws anything in there and which not always
part of reports).
>
>> It'd nicer if we can check assembler first and opt-in feature
>> visibility in Kconfig.
>>
>> Cc: Masahiro Yamada <[email protected]>
>> Cc: Will Deacon <[email protected]>
>> Cc: Marc Zyngier <[email protected]>
>> Cc: Ard Biesheuvel <[email protected]>
>> Signed-off-by: Vladimir Murzin <[email protected]>
>> ---
>> scripts/Kconfig.include | 4 ++++
>> 1 file changed, 4 insertions(+)
>
> One issue I have with doing the check like this is that if somebody sends
> you a .config with e.g. ARM64_LSE_ATOMICS=y and you try to build a kernel
> using that .config and an old toolchain, the option is silently dropped.
I see... at least we have some tools like ./scripts/diffconfig
>
> I think the diagnostic is actually useful in this case.
Fully agree on diagnostic side, any suggestions how it can be improved?
Cheers
Vladimir
>
> Will
>
There are cases where the whole feature, for instance arm64/lse or
arm/crypto, can depend on assembler. Current practice is to report
buildtime that selected feature is not supported, which can be quite
annoying...
It'd nicer if we can check assembler first and opt-in feature
visibility in Kconfig.
Cc: Masahiro Yamada <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Marc Zyngier <[email protected]>
Cc: Ard Biesheuvel <[email protected]>
Signed-off-by: Vladimir Murzin <[email protected]>
---
scripts/Kconfig.include | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/scripts/Kconfig.include b/scripts/Kconfig.include
index dad5583..07c145c 100644
--- a/scripts/Kconfig.include
+++ b/scripts/Kconfig.include
@@ -22,6 +22,10 @@ success = $(if-success,$(1),y,n)
# Return y if the compiler supports <flag>, n otherwise
cc-option = $(success,$(CC) -Werror $(1) -E -x c /dev/null -o /dev/null)
+# $(as-instr,<instr>)
+# Return y if the assembler supports <instr>, n otherwise
+as-instr = $(success,printf "%b\n" "$(1)" | $(CC) -Werror -c -x assembler -o /dev/null -)
+
# $(ld-option,<flag>)
# Return y if the linker supports <flag>, n otherwise
ld-option = $(success,$(LD) -v $(1))
--
1.9.1
So it is available everywhere and there is no need to keep
CONFIG_ARM64 workaround ;)
Cc: Marc Zyngier <[email protected]>
Signed-off-by: Vladimir Murzin <[email protected]>
---
arch/arm64/Kconfig | 3 +++
arch/arm64/Makefile | 9 ++-------
2 files changed, 5 insertions(+), 7 deletions(-)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 7978aee..86fc357 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -287,6 +287,9 @@ config ARCH_SUPPORTS_UPROBES
config ARCH_PROC_KCORE_TEXT
def_bool y
+config BROKEN_GAS_INST
+ def_bool y if !$(as-instr,1:\n.inst 0\n.rept . - 1b\n\nnop\n.endr\n)
+
source "arch/arm64/Kconfig.platforms"
menu "Bus support"
diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index 3054757..9860d3a 100644
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -32,17 +32,12 @@ endif
KBUILD_DEFCONFIG := defconfig
-ifeq ($(CONFIG_ARM64), y)
-brokengasinst := $(call as-instr,1:\n.inst 0\n.rept . - 1b\n\nnop\n.endr\n,,-DCONFIG_BROKEN_GAS_INST=1)
-
- ifneq ($(brokengasinst),)
+ifeq ($(CONFIG_BROKEN_GAS_INST),y)
$(warning Detected assembler with broken .inst; disassembly will be unreliable)
- endif
endif
-KBUILD_CFLAGS += -mgeneral-regs-only $(brokengasinst)
+KBUILD_CFLAGS += -mgeneral-regs-only
KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
-KBUILD_AFLAGS += $(brokengasinst)
KBUILD_CFLAGS += $(call cc-option,-mabi=lp64)
KBUILD_AFLAGS += $(call cc-option,-mabi=lp64)
--
1.9.1
So we can advertise only those entries which dependency is satisfied.
Cc: Ard Biesheuvel <[email protected]>
Signed-off-by: Vladimir Murzin <[email protected]>
---
arch/arm/crypto/Kconfig | 31 +++++++++++++++++++++----------
arch/arm/crypto/Makefile | 31 ++++++-------------------------
2 files changed, 27 insertions(+), 35 deletions(-)
diff --git a/arch/arm/crypto/Kconfig b/arch/arm/crypto/Kconfig
index ef0c7fe..f437a91f 100644
--- a/arch/arm/crypto/Kconfig
+++ b/arch/arm/crypto/Kconfig
@@ -9,6 +9,12 @@ menuconfig ARM_CRYPTO
if ARM_CRYPTO
+config ARM_AS_HAS_CE
+ def_bool $(as-instr,.fpu crypto-neon-fp-armv8)
+
+config ARM_AS_HAS_CRC
+ def_bool $(as-instr,.arch armv8-a\n.arch_extension crc)
+
config CRYPTO_SHA1_ARM
tristate "SHA1 digest algorithm (ARM-asm)"
select CRYPTO_SHA1
@@ -30,21 +36,21 @@ config CRYPTO_SHA1_ARM_NEON
config CRYPTO_SHA1_ARM_CE
tristate "SHA1 digest algorithm (ARM v8 Crypto Extensions)"
- depends on KERNEL_MODE_NEON
+ depends on KERNEL_MODE_NEON && ARM_AS_HAS_CE
select CRYPTO_SHA1_ARM
select CRYPTO_HASH
help
SHA-1 secure hash standard (FIPS 180-1/DFIPS 180-2) implemented
- using special ARMv8 Crypto Extensions.
+ using special ARMv8 Crypto Extensions (need binutils 2.23 or higher).
config CRYPTO_SHA2_ARM_CE
tristate "SHA-224/256 digest algorithm (ARM v8 Crypto Extensions)"
- depends on KERNEL_MODE_NEON
+ depends on KERNEL_MODE_NEON && ARM_AS_HAS_CE
select CRYPTO_SHA256_ARM
select CRYPTO_HASH
help
SHA-256 secure hash standard (DFIPS 180-2) implemented
- using special ARMv8 Crypto Extensions.
+ using special ARMv8 Crypto Extensions (need binutils 2.23 or higher).
config CRYPTO_SHA256_ARM
tristate "SHA-224/256 digest algorithm (ARM-asm and NEON)"
@@ -87,16 +93,16 @@ config CRYPTO_AES_ARM_BS
config CRYPTO_AES_ARM_CE
tristate "Accelerated AES using ARMv8 Crypto Extensions"
- depends on KERNEL_MODE_NEON
+ depends on KERNEL_MODE_NEON && ARM_AS_HAS_CE
select CRYPTO_BLKCIPHER
select CRYPTO_SIMD
help
Use an implementation of AES in CBC, CTR and XTS modes that uses
- ARMv8 Crypto Extensions
+ ARMv8 Crypto Extensions (need binutils 2.23 or higher)
config CRYPTO_GHASH_ARM_CE
tristate "PMULL-accelerated GHASH using NEON/ARMv8 Crypto Extensions"
- depends on KERNEL_MODE_NEON
+ depends on KERNEL_MODE_NEON && ARM_AS_HAS_CE
select CRYPTO_HASH
select CRYPTO_CRYPTD
select CRYPTO_GF128MUL
@@ -104,17 +110,22 @@ config CRYPTO_GHASH_ARM_CE
Use an implementation of GHASH (used by the GCM AEAD chaining mode)
that uses the 64x64 to 128 bit polynomial multiplication (vmull.p64)
that is part of the ARMv8 Crypto Extensions, or a slower variant that
- uses the vmull.p8 instruction that is part of the basic NEON ISA.
+ uses the vmull.p8 instruction that is part of the basic NEON ISA (need
+ binutils 2.23 or higher).
config CRYPTO_CRCT10DIF_ARM_CE
tristate "CRCT10DIF digest algorithm using PMULL instructions"
- depends on KERNEL_MODE_NEON && CRC_T10DIF
+ depends on KERNEL_MODE_NEON && CRC_T10DIF && ARM_AS_HAS_CE
select CRYPTO_HASH
+ help
+ Need binutils 2.23 or higher
config CRYPTO_CRC32_ARM_CE
tristate "CRC32(C) digest algorithm using CRC and/or PMULL instructions"
- depends on KERNEL_MODE_NEON && CRC32
+ depends on KERNEL_MODE_NEON && CRC32 && ARM_AS_HAS_CRC
select CRYPTO_HASH
+ help
+ Need binutils 2.23 or higher
config CRYPTO_CHACHA20_NEON
tristate "NEON accelerated ChaCha20 symmetric cipher"
diff --git a/arch/arm/crypto/Makefile b/arch/arm/crypto/Makefile
index bd5bcee..e897327 100644
--- a/arch/arm/crypto/Makefile
+++ b/arch/arm/crypto/Makefile
@@ -11,32 +11,13 @@ obj-$(CONFIG_CRYPTO_SHA256_ARM) += sha256-arm.o
obj-$(CONFIG_CRYPTO_SHA512_ARM) += sha512-arm.o
obj-$(CONFIG_CRYPTO_CHACHA20_NEON) += chacha20-neon.o
-ce-obj-$(CONFIG_CRYPTO_AES_ARM_CE) += aes-arm-ce.o
-ce-obj-$(CONFIG_CRYPTO_SHA1_ARM_CE) += sha1-arm-ce.o
-ce-obj-$(CONFIG_CRYPTO_SHA2_ARM_CE) += sha2-arm-ce.o
-ce-obj-$(CONFIG_CRYPTO_GHASH_ARM_CE) += ghash-arm-ce.o
-ce-obj-$(CONFIG_CRYPTO_CRCT10DIF_ARM_CE) += crct10dif-arm-ce.o
-crc-obj-$(CONFIG_CRYPTO_CRC32_ARM_CE) += crc32-arm-ce.o
+obj-$(CONFIG_CRYPTO_AES_ARM_CE) += aes-arm-ce.o
+obj-$(CONFIG_CRYPTO_SHA1_ARM_CE) += sha1-arm-ce.o
+obj-$(CONFIG_CRYPTO_SHA2_ARM_CE) += sha2-arm-ce.o
+obj-$(CONFIG_CRYPTO_GHASH_ARM_CE) += ghash-arm-ce.o
+obj-$(CONFIG_CRYPTO_CRCT10DIF_ARM_CE) += crct10dif-arm-ce.o
-ifneq ($(crc-obj-y)$(crc-obj-m),)
-ifeq ($(call as-instr,.arch armv8-a\n.arch_extension crc,y,n),y)
-ce-obj-y += $(crc-obj-y)
-ce-obj-m += $(crc-obj-m)
-else
-$(warning These CRC Extensions modules need binutils 2.23 or higher)
-$(warning $(crc-obj-y) $(crc-obj-m))
-endif
-endif
-
-ifneq ($(ce-obj-y)$(ce-obj-m),)
-ifeq ($(call as-instr,.fpu crypto-neon-fp-armv8,y,n),y)
-obj-y += $(ce-obj-y)
-obj-m += $(ce-obj-m)
-else
-$(warning These ARMv8 Crypto Extensions modules need binutils 2.23 or higher)
-$(warning $(ce-obj-y) $(ce-obj-m))
-endif
-endif
+obj-$(CONFIG_CRYPTO_CRC32_ARM_CE) += crc32-arm-ce.o
aes-arm-y := aes-cipher-core.o aes-cipher-glue.o
aes-arm-bs-y := aes-neonbs-core.o aes-neonbs-glue.o
--
1.9.1
On Wed, Nov 07, 2018 at 09:40:05AM +0000, Vladimir Murzin wrote:
> There are cases where the whole feature, for instance arm64/lse or
> arm/crypto, can depend on assembler. Current practice is to report
> buildtime that selected feature is not supported, which can be quite
> annoying...
Why is it annoying? You still end up with a working kernel.
> It'd nicer if we can check assembler first and opt-in feature
> visibility in Kconfig.
>
> Cc: Masahiro Yamada <[email protected]>
> Cc: Will Deacon <[email protected]>
> Cc: Marc Zyngier <[email protected]>
> Cc: Ard Biesheuvel <[email protected]>
> Signed-off-by: Vladimir Murzin <[email protected]>
> ---
> scripts/Kconfig.include | 4 ++++
> 1 file changed, 4 insertions(+)
One issue I have with doing the check like this is that if somebody sends
you a .config with e.g. ARM64_LSE_ATOMICS=y and you try to build a kernel
using that .config and an old toolchain, the option is silently dropped.
I think the diagnostic is actually useful in this case.
Will
So we can simply hide LSE support if dependency is not satisfied.
Cc: Will Deacon <[email protected]>
Signed-off-by: Vladimir Murzin <[email protected]>
---
arch/arm64/Kconfig | 1 +
arch/arm64/Makefile | 13 ++-----------
arch/arm64/include/asm/atomic.h | 2 +-
arch/arm64/include/asm/lse.h | 6 +++---
arch/arm64/kernel/cpufeature.c | 4 ++--
5 files changed, 9 insertions(+), 17 deletions(-)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 964f682..7978aee 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -1072,6 +1072,7 @@ config ARM64_PAN
config ARM64_LSE_ATOMICS
bool "Atomic instructions"
default y
+ depends on $(as-instr,.arch_extension lse)
help
As part of the Large System Extensions, ARMv8.1 introduces new
atomic instructions that are designed specifically to scale in
diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index b4e994c..3054757 100644
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -32,15 +32,6 @@ endif
KBUILD_DEFCONFIG := defconfig
-# Check for binutils support for specific extensions
-lseinstr := $(call as-instr,.arch_extension lse,-DCONFIG_AS_LSE=1)
-
-ifeq ($(CONFIG_ARM64_LSE_ATOMICS), y)
- ifeq ($(lseinstr),)
-$(warning LSE atomics not supported by binutils)
- endif
-endif
-
ifeq ($(CONFIG_ARM64), y)
brokengasinst := $(call as-instr,1:\n.inst 0\n.rept . - 1b\n\nnop\n.endr\n,,-DCONFIG_BROKEN_GAS_INST=1)
@@ -49,9 +40,9 @@ $(warning Detected assembler with broken .inst; disassembly will be unreliable)
endif
endif
-KBUILD_CFLAGS += -mgeneral-regs-only $(lseinstr) $(brokengasinst)
+KBUILD_CFLAGS += -mgeneral-regs-only $(brokengasinst)
KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
-KBUILD_AFLAGS += $(lseinstr) $(brokengasinst)
+KBUILD_AFLAGS += $(brokengasinst)
KBUILD_CFLAGS += $(call cc-option,-mabi=lp64)
KBUILD_AFLAGS += $(call cc-option,-mabi=lp64)
diff --git a/arch/arm64/include/asm/atomic.h b/arch/arm64/include/asm/atomic.h
index 9bca54d..9d8d029 100644
--- a/arch/arm64/include/asm/atomic.h
+++ b/arch/arm64/include/asm/atomic.h
@@ -30,7 +30,7 @@
#define __ARM64_IN_ATOMIC_IMPL
-#if defined(CONFIG_ARM64_LSE_ATOMICS) && defined(CONFIG_AS_LSE)
+#ifdef CONFIG_ARM64_LSE_ATOMICS
#include <asm/atomic_lse.h>
#else
#include <asm/atomic_ll_sc.h>
diff --git a/arch/arm64/include/asm/lse.h b/arch/arm64/include/asm/lse.h
index 8262325..1fd31c7 100644
--- a/arch/arm64/include/asm/lse.h
+++ b/arch/arm64/include/asm/lse.h
@@ -2,7 +2,7 @@
#ifndef __ASM_LSE_H
#define __ASM_LSE_H
-#if defined(CONFIG_AS_LSE) && defined(CONFIG_ARM64_LSE_ATOMICS)
+#ifdef CONFIG_ARM64_LSE_ATOMICS
#include <linux/compiler_types.h>
#include <linux/export.h>
@@ -36,7 +36,7 @@
ALTERNATIVE(llsc, lse, ARM64_HAS_LSE_ATOMICS)
#endif /* __ASSEMBLER__ */
-#else /* CONFIG_AS_LSE && CONFIG_ARM64_LSE_ATOMICS */
+#else /* CONFIG_ARM64_LSE_ATOMICS */
#ifdef __ASSEMBLER__
@@ -53,5 +53,5 @@
#define ARM64_LSE_ATOMIC_INSN(llsc, lse) llsc
#endif /* __ASSEMBLER__ */
-#endif /* CONFIG_AS_LSE && CONFIG_ARM64_LSE_ATOMICS */
+#endif /* CONFIG_ARM64_LSE_ATOMICS */
#endif /* __ASM_LSE_H */
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 74e9dcb..46f1bac 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -1170,7 +1170,7 @@ static void cpu_clear_disr(const struct arm64_cpu_capabilities *__unused)
.cpu_enable = cpu_enable_pan,
},
#endif /* CONFIG_ARM64_PAN */
-#if defined(CONFIG_AS_LSE) && defined(CONFIG_ARM64_LSE_ATOMICS)
+#ifdef CONFIG_ARM64_LSE_ATOMICS
{
.desc = "LSE atomic instructions",
.capability = ARM64_HAS_LSE_ATOMICS,
@@ -1181,7 +1181,7 @@ static void cpu_clear_disr(const struct arm64_cpu_capabilities *__unused)
.sign = FTR_UNSIGNED,
.min_field_value = 2,
},
-#endif /* CONFIG_AS_LSE && CONFIG_ARM64_LSE_ATOMICS */
+#endif /* CONFIG_ARM64_LSE_ATOMICS */
{
.desc = "Software prefetching using PRFM",
.capability = ARM64_HAS_NO_HW_PREFETCH,
--
1.9.1