* [PATCH] LoongArch: Remove unused header compiler.h
@ 2022-07-21 2:11 Jun Yi
2022-07-21 2:52 ` Huacai Chen
2022-07-21 3:20 ` WANG Xuerui
0 siblings, 2 replies; 7+ messages in thread
From: Jun Yi @ 2022-07-21 2:11 UTC (permalink / raw)
To: Huacai Chen; +Cc: WANG Xuerui, loongarch, linux-kernel, Jiaxun Yang
Loongarch not used arch-specific compiler.h
Signed-off-by: Jun Yi <yijun@loongson.cn>
---
arch/loongarch/Kconfig | 1 -
arch/loongarch/include/asm/atomic.h | 9 ++++-----
arch/loongarch/include/asm/compiler.h | 15 ---------------
arch/loongarch/include/asm/futex.h | 5 ++---
arch/loongarch/include/asm/irqflags.h | 1 -
arch/loongarch/include/asm/local.h | 1 -
arch/loongarch/kernel/reset.c | 1 -
arch/loongarch/lib/delay.c | 1 -
8 files changed, 6 insertions(+), 28 deletions(-)
delete mode 100644 arch/loongarch/include/asm/compiler.h
diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index 53a912befb62..89da3e09084e 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -69,7 +69,6 @@ config LOONGARCH
select GENERIC_TIME_VSYSCALL
select GPIOLIB
select HAVE_ARCH_AUDITSYSCALL
- select HAVE_ARCH_COMPILER_H
select HAVE_ARCH_MMAP_RND_BITS if MMU
select HAVE_ARCH_SECCOMP_FILTER
select HAVE_ARCH_TRACEHOOK
diff --git a/arch/loongarch/include/asm/atomic.h b/arch/loongarch/include/asm/atomic.h
index 979367ad4e2c..b5e2e3201af1 100644
--- a/arch/loongarch/include/asm/atomic.h
+++ b/arch/loongarch/include/asm/atomic.h
@@ -10,7 +10,6 @@
#include <linux/types.h>
#include <asm/barrier.h>
#include <asm/cmpxchg.h>
-#include <asm/compiler.h>
#if __SIZEOF_LONG__ == 4
#define __LL "ll.w "
@@ -164,7 +163,7 @@ static inline int arch_atomic_sub_if_positive(int i, atomic_t *v)
"2: \n"
__WEAK_LLSC_MB
: "=&r" (result), "=&r" (temp),
- "+" GCC_OFF_SMALL_ASM() (v->counter)
+ "+ZC" (v->counter)
: "I" (-i));
} else {
__asm__ __volatile__(
@@ -177,7 +176,7 @@ static inline int arch_atomic_sub_if_positive(int i, atomic_t *v)
"2: \n"
__WEAK_LLSC_MB
: "=&r" (result), "=&r" (temp),
- "+" GCC_OFF_SMALL_ASM() (v->counter)
+ "+ZC" (v->counter)
: "r" (i));
}
@@ -327,7 +326,7 @@ static inline long arch_atomic64_sub_if_positive(long i, atomic64_t *v)
"2: \n"
__WEAK_LLSC_MB
: "=&r" (result), "=&r" (temp),
- "+" GCC_OFF_SMALL_ASM() (v->counter)
+ "+ZC" (v->counter)
: "I" (-i));
} else {
__asm__ __volatile__(
@@ -340,7 +339,7 @@ static inline long arch_atomic64_sub_if_positive(long i, atomic64_t *v)
"2: \n"
__WEAK_LLSC_MB
: "=&r" (result), "=&r" (temp),
- "+" GCC_OFF_SMALL_ASM() (v->counter)
+ "+ZC" (v->counter)
: "r" (i));
}
diff --git a/arch/loongarch/include/asm/compiler.h b/arch/loongarch/include/asm/compiler.h
deleted file mode 100644
index 657cebe70ace..000000000000
--- a/arch/loongarch/include/asm/compiler.h
+++ /dev/null
@@ -1,15 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
- */
-#ifndef _ASM_COMPILER_H
-#define _ASM_COMPILER_H
-
-#define GCC_OFF_SMALL_ASM() "ZC"
-
-#define LOONGARCH_ISA_LEVEL "loongarch"
-#define LOONGARCH_ISA_ARCH_LEVEL "arch=loongarch"
-#define LOONGARCH_ISA_LEVEL_RAW loongarch
-#define LOONGARCH_ISA_ARCH_LEVEL_RAW LOONGARCH_ISA_LEVEL_RAW
-
-#endif /* _ASM_COMPILER_H */
diff --git a/arch/loongarch/include/asm/futex.h b/arch/loongarch/include/asm/futex.h
index 9de8231694ec..e28b65d9c67a 100644
--- a/arch/loongarch/include/asm/futex.h
+++ b/arch/loongarch/include/asm/futex.h
@@ -8,7 +8,6 @@
#include <linux/futex.h>
#include <linux/uaccess.h>
#include <asm/barrier.h>
-#include <asm/compiler.h>
#include <asm/errno.h>
#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \
@@ -95,8 +94,8 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 oldval, u32 newv
" "__UA_ADDR "\t1b, 4b \n"
" "__UA_ADDR "\t2b, 4b \n"
" .previous \n"
- : "+r" (ret), "=&r" (val), "=" GCC_OFF_SMALL_ASM() (*uaddr)
- : GCC_OFF_SMALL_ASM() (*uaddr), "Jr" (oldval), "Jr" (newval),
+ : "+r" (ret), "=&r" (val), "=ZC" (*uaddr)
+ : "ZC" (*uaddr), "Jr" (oldval), "Jr" (newval),
"i" (-EFAULT)
: "memory", "t0");
diff --git a/arch/loongarch/include/asm/irqflags.h b/arch/loongarch/include/asm/irqflags.h
index 52121cd791fe..319a8c616f1f 100644
--- a/arch/loongarch/include/asm/irqflags.h
+++ b/arch/loongarch/include/asm/irqflags.h
@@ -9,7 +9,6 @@
#include <linux/compiler.h>
#include <linux/stringify.h>
-#include <asm/compiler.h>
#include <asm/loongarch.h>
static inline void arch_local_irq_enable(void)
diff --git a/arch/loongarch/include/asm/local.h b/arch/loongarch/include/asm/local.h
index 2052a2267337..65fbbae9fc4d 100644
--- a/arch/loongarch/include/asm/local.h
+++ b/arch/loongarch/include/asm/local.h
@@ -9,7 +9,6 @@
#include <linux/bitops.h>
#include <linux/atomic.h>
#include <asm/cmpxchg.h>
-#include <asm/compiler.h>
typedef struct {
atomic_long_t a;
diff --git a/arch/loongarch/kernel/reset.c b/arch/loongarch/kernel/reset.c
index 2b86469e4718..800c965a17ea 100644
--- a/arch/loongarch/kernel/reset.c
+++ b/arch/loongarch/kernel/reset.c
@@ -13,7 +13,6 @@
#include <linux/console.h>
#include <acpi/reboot.h>
-#include <asm/compiler.h>
#include <asm/idle.h>
#include <asm/loongarch.h>
#include <asm/reboot.h>
diff --git a/arch/loongarch/lib/delay.c b/arch/loongarch/lib/delay.c
index 5d856694fcfe..831d4761f385 100644
--- a/arch/loongarch/lib/delay.c
+++ b/arch/loongarch/lib/delay.c
@@ -7,7 +7,6 @@
#include <linux/smp.h>
#include <linux/timex.h>
-#include <asm/compiler.h>
#include <asm/processor.h>
void __delay(unsigned long cycles)
--
2.31.1
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH] LoongArch: Remove unused header compiler.h
2022-07-21 2:11 [PATCH] LoongArch: Remove unused header compiler.h Jun Yi
@ 2022-07-21 2:52 ` Huacai Chen
2022-07-21 3:17 ` WANG Xuerui
2022-07-21 3:20 ` WANG Xuerui
1 sibling, 1 reply; 7+ messages in thread
From: Huacai Chen @ 2022-07-21 2:52 UTC (permalink / raw)
To: Jun Yi; +Cc: WANG Xuerui, loongarch, LKML, Jiaxun Yang
Hi, Jun,
On Thu, Jul 21, 2022 at 10:11 AM Jun Yi <yijun@loongson.cn> wrote:
>
> Loongarch not used arch-specific compiler.h
I'm not sure whether compiler.h will be used in future. If it will be
used, I want to keep it as is. Xuerui, what do you think about it?
Huacai
>
> Signed-off-by: Jun Yi <yijun@loongson.cn>
> ---
> arch/loongarch/Kconfig | 1 -
> arch/loongarch/include/asm/atomic.h | 9 ++++-----
> arch/loongarch/include/asm/compiler.h | 15 ---------------
> arch/loongarch/include/asm/futex.h | 5 ++---
> arch/loongarch/include/asm/irqflags.h | 1 -
> arch/loongarch/include/asm/local.h | 1 -
> arch/loongarch/kernel/reset.c | 1 -
> arch/loongarch/lib/delay.c | 1 -
> 8 files changed, 6 insertions(+), 28 deletions(-)
> delete mode 100644 arch/loongarch/include/asm/compiler.h
>
> diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
> index 53a912befb62..89da3e09084e 100644
> --- a/arch/loongarch/Kconfig
> +++ b/arch/loongarch/Kconfig
> @@ -69,7 +69,6 @@ config LOONGARCH
> select GENERIC_TIME_VSYSCALL
> select GPIOLIB
> select HAVE_ARCH_AUDITSYSCALL
> - select HAVE_ARCH_COMPILER_H
> select HAVE_ARCH_MMAP_RND_BITS if MMU
> select HAVE_ARCH_SECCOMP_FILTER
> select HAVE_ARCH_TRACEHOOK
> diff --git a/arch/loongarch/include/asm/atomic.h b/arch/loongarch/include/asm/atomic.h
> index 979367ad4e2c..b5e2e3201af1 100644
> --- a/arch/loongarch/include/asm/atomic.h
> +++ b/arch/loongarch/include/asm/atomic.h
> @@ -10,7 +10,6 @@
> #include <linux/types.h>
> #include <asm/barrier.h>
> #include <asm/cmpxchg.h>
> -#include <asm/compiler.h>
>
> #if __SIZEOF_LONG__ == 4
> #define __LL "ll.w "
> @@ -164,7 +163,7 @@ static inline int arch_atomic_sub_if_positive(int i, atomic_t *v)
> "2: \n"
> __WEAK_LLSC_MB
> : "=&r" (result), "=&r" (temp),
> - "+" GCC_OFF_SMALL_ASM() (v->counter)
> + "+ZC" (v->counter)
> : "I" (-i));
> } else {
> __asm__ __volatile__(
> @@ -177,7 +176,7 @@ static inline int arch_atomic_sub_if_positive(int i, atomic_t *v)
> "2: \n"
> __WEAK_LLSC_MB
> : "=&r" (result), "=&r" (temp),
> - "+" GCC_OFF_SMALL_ASM() (v->counter)
> + "+ZC" (v->counter)
> : "r" (i));
> }
>
> @@ -327,7 +326,7 @@ static inline long arch_atomic64_sub_if_positive(long i, atomic64_t *v)
> "2: \n"
> __WEAK_LLSC_MB
> : "=&r" (result), "=&r" (temp),
> - "+" GCC_OFF_SMALL_ASM() (v->counter)
> + "+ZC" (v->counter)
> : "I" (-i));
> } else {
> __asm__ __volatile__(
> @@ -340,7 +339,7 @@ static inline long arch_atomic64_sub_if_positive(long i, atomic64_t *v)
> "2: \n"
> __WEAK_LLSC_MB
> : "=&r" (result), "=&r" (temp),
> - "+" GCC_OFF_SMALL_ASM() (v->counter)
> + "+ZC" (v->counter)
> : "r" (i));
> }
>
> diff --git a/arch/loongarch/include/asm/compiler.h b/arch/loongarch/include/asm/compiler.h
> deleted file mode 100644
> index 657cebe70ace..000000000000
> --- a/arch/loongarch/include/asm/compiler.h
> +++ /dev/null
> @@ -1,15 +0,0 @@
> -/* SPDX-License-Identifier: GPL-2.0 */
> -/*
> - * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
> - */
> -#ifndef _ASM_COMPILER_H
> -#define _ASM_COMPILER_H
> -
> -#define GCC_OFF_SMALL_ASM() "ZC"
> -
> -#define LOONGARCH_ISA_LEVEL "loongarch"
> -#define LOONGARCH_ISA_ARCH_LEVEL "arch=loongarch"
> -#define LOONGARCH_ISA_LEVEL_RAW loongarch
> -#define LOONGARCH_ISA_ARCH_LEVEL_RAW LOONGARCH_ISA_LEVEL_RAW
> -
> -#endif /* _ASM_COMPILER_H */
> diff --git a/arch/loongarch/include/asm/futex.h b/arch/loongarch/include/asm/futex.h
> index 9de8231694ec..e28b65d9c67a 100644
> --- a/arch/loongarch/include/asm/futex.h
> +++ b/arch/loongarch/include/asm/futex.h
> @@ -8,7 +8,6 @@
> #include <linux/futex.h>
> #include <linux/uaccess.h>
> #include <asm/barrier.h>
> -#include <asm/compiler.h>
> #include <asm/errno.h>
>
> #define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \
> @@ -95,8 +94,8 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 oldval, u32 newv
> " "__UA_ADDR "\t1b, 4b \n"
> " "__UA_ADDR "\t2b, 4b \n"
> " .previous \n"
> - : "+r" (ret), "=&r" (val), "=" GCC_OFF_SMALL_ASM() (*uaddr)
> - : GCC_OFF_SMALL_ASM() (*uaddr), "Jr" (oldval), "Jr" (newval),
> + : "+r" (ret), "=&r" (val), "=ZC" (*uaddr)
> + : "ZC" (*uaddr), "Jr" (oldval), "Jr" (newval),
> "i" (-EFAULT)
> : "memory", "t0");
>
> diff --git a/arch/loongarch/include/asm/irqflags.h b/arch/loongarch/include/asm/irqflags.h
> index 52121cd791fe..319a8c616f1f 100644
> --- a/arch/loongarch/include/asm/irqflags.h
> +++ b/arch/loongarch/include/asm/irqflags.h
> @@ -9,7 +9,6 @@
>
> #include <linux/compiler.h>
> #include <linux/stringify.h>
> -#include <asm/compiler.h>
> #include <asm/loongarch.h>
>
> static inline void arch_local_irq_enable(void)
> diff --git a/arch/loongarch/include/asm/local.h b/arch/loongarch/include/asm/local.h
> index 2052a2267337..65fbbae9fc4d 100644
> --- a/arch/loongarch/include/asm/local.h
> +++ b/arch/loongarch/include/asm/local.h
> @@ -9,7 +9,6 @@
> #include <linux/bitops.h>
> #include <linux/atomic.h>
> #include <asm/cmpxchg.h>
> -#include <asm/compiler.h>
>
> typedef struct {
> atomic_long_t a;
> diff --git a/arch/loongarch/kernel/reset.c b/arch/loongarch/kernel/reset.c
> index 2b86469e4718..800c965a17ea 100644
> --- a/arch/loongarch/kernel/reset.c
> +++ b/arch/loongarch/kernel/reset.c
> @@ -13,7 +13,6 @@
> #include <linux/console.h>
>
> #include <acpi/reboot.h>
> -#include <asm/compiler.h>
> #include <asm/idle.h>
> #include <asm/loongarch.h>
> #include <asm/reboot.h>
> diff --git a/arch/loongarch/lib/delay.c b/arch/loongarch/lib/delay.c
> index 5d856694fcfe..831d4761f385 100644
> --- a/arch/loongarch/lib/delay.c
> +++ b/arch/loongarch/lib/delay.c
> @@ -7,7 +7,6 @@
> #include <linux/smp.h>
> #include <linux/timex.h>
>
> -#include <asm/compiler.h>
> #include <asm/processor.h>
>
> void __delay(unsigned long cycles)
> --
> 2.31.1
>
>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] LoongArch: Remove unused header compiler.h
2022-07-21 2:52 ` Huacai Chen
@ 2022-07-21 3:17 ` WANG Xuerui
2022-07-21 3:22 ` Huacai Chen
0 siblings, 1 reply; 7+ messages in thread
From: WANG Xuerui @ 2022-07-21 3:17 UTC (permalink / raw)
To: Huacai Chen, Jun Yi; +Cc: WANG Xuerui, loongarch, LKML, Jiaxun Yang
Hi YI Jun and Huacai,
On 2022/7/21 10:52, Huacai Chen wrote:
> Hi, Jun,
>
> On Thu, Jul 21, 2022 at 10:11 AM Jun Yi <yijun@loongson.cn> wrote:
>> Loongarch not used arch-specific compiler.h
> I'm not sure whether compiler.h will be used in future. If it will be
> used, I want to keep it as is. Xuerui, what do you think about it?
I surveyed all the existing arch compiler.h in the tree:
$ find ./arch -name compiler.h
./arch/alpha/include/asm/compiler.h
./arch/alpha/include/uapi/asm/compiler.h
./arch/arm/include/asm/compiler.h
./arch/arm64/include/asm/compiler.h
./arch/mips/include/asm/compiler.h
./arch/loongarch/include/asm/compiler.h
Of all these occurrences:
- alpha needs to ensure a certain insn is being emitted from time to
time, with plain C constructs (or built-ins) on compiler versions with
said support, falling back to inline asm otherwise;
- arm and arm64 both need some inline assembly help (of different sort),
with arm64 stuffing some pointer authentication helpers into this file too;
- mips, which is obviously what the loongarch version is based on, needs
(1) a kludge for older compilers to fix delay slot filling around
__builtin_unreachable, (2) definitions for explicit arch level
selection. There is also the historical GCC_OFF_SMALL_ASM() constraint
definition that was rendered redundant by commit 4abaacc704729 ("MIPS:
remove GCC < 4.9 support").
For loongarch, the "ZC" constraint (I don't think it was a coincidence
BTW) should be usable for all present and future hardware, so I do think
the GCC_OFF_SMALL_ASM() here is redundant. We may want to remove the
mips one too. And the arch level thing is not currently needed either,
future revisions to the LoongArch ISA should be largely backwards
compatible, so it could be a long time before such explicit selection of
arch level is necessary, for exact control over emitted insn.
So overall, I'm in favor of removing this header for now.
> Huacai
>> Signed-off-by: Jun Yi <yijun@loongson.cn>
>> ---
>> arch/loongarch/Kconfig | 1 -
>> arch/loongarch/include/asm/atomic.h | 9 ++++-----
>> arch/loongarch/include/asm/compiler.h | 15 ---------------
>> arch/loongarch/include/asm/futex.h | 5 ++---
>> arch/loongarch/include/asm/irqflags.h | 1 -
>> arch/loongarch/include/asm/local.h | 1 -
>> arch/loongarch/kernel/reset.c | 1 -
>> arch/loongarch/lib/delay.c | 1 -
>> 8 files changed, 6 insertions(+), 28 deletions(-)
>> delete mode 100644 arch/loongarch/include/asm/compiler.h
>>
>> diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
>> index 53a912befb62..89da3e09084e 100644
>> --- a/arch/loongarch/Kconfig
>> +++ b/arch/loongarch/Kconfig
>> @@ -69,7 +69,6 @@ config LOONGARCH
>> select GENERIC_TIME_VSYSCALL
>> select GPIOLIB
>> select HAVE_ARCH_AUDITSYSCALL
>> - select HAVE_ARCH_COMPILER_H
>> select HAVE_ARCH_MMAP_RND_BITS if MMU
>> select HAVE_ARCH_SECCOMP_FILTER
>> select HAVE_ARCH_TRACEHOOK
>> diff --git a/arch/loongarch/include/asm/atomic.h b/arch/loongarch/include/asm/atomic.h
>> index 979367ad4e2c..b5e2e3201af1 100644
>> --- a/arch/loongarch/include/asm/atomic.h
>> +++ b/arch/loongarch/include/asm/atomic.h
>> @@ -10,7 +10,6 @@
>> #include <linux/types.h>
>> #include <asm/barrier.h>
>> #include <asm/cmpxchg.h>
>> -#include <asm/compiler.h>
>>
>> #if __SIZEOF_LONG__ == 4
>> #define __LL "ll.w "
>> @@ -164,7 +163,7 @@ static inline int arch_atomic_sub_if_positive(int i, atomic_t *v)
>> "2: \n"
>> __WEAK_LLSC_MB
>> : "=&r" (result), "=&r" (temp),
>> - "+" GCC_OFF_SMALL_ASM() (v->counter)
>> + "+ZC" (v->counter)
>> : "I" (-i));
>> } else {
>> __asm__ __volatile__(
>> @@ -177,7 +176,7 @@ static inline int arch_atomic_sub_if_positive(int i, atomic_t *v)
>> "2: \n"
>> __WEAK_LLSC_MB
>> : "=&r" (result), "=&r" (temp),
>> - "+" GCC_OFF_SMALL_ASM() (v->counter)
>> + "+ZC" (v->counter)
>> : "r" (i));
>> }
>>
>> @@ -327,7 +326,7 @@ static inline long arch_atomic64_sub_if_positive(long i, atomic64_t *v)
>> "2: \n"
>> __WEAK_LLSC_MB
>> : "=&r" (result), "=&r" (temp),
>> - "+" GCC_OFF_SMALL_ASM() (v->counter)
>> + "+ZC" (v->counter)
>> : "I" (-i));
>> } else {
>> __asm__ __volatile__(
>> @@ -340,7 +339,7 @@ static inline long arch_atomic64_sub_if_positive(long i, atomic64_t *v)
>> "2: \n"
>> __WEAK_LLSC_MB
>> : "=&r" (result), "=&r" (temp),
>> - "+" GCC_OFF_SMALL_ASM() (v->counter)
>> + "+ZC" (v->counter)
>> : "r" (i));
>> }
>>
>> diff --git a/arch/loongarch/include/asm/compiler.h b/arch/loongarch/include/asm/compiler.h
>> deleted file mode 100644
>> index 657cebe70ace..000000000000
>> --- a/arch/loongarch/include/asm/compiler.h
>> +++ /dev/null
>> @@ -1,15 +0,0 @@
>> -/* SPDX-License-Identifier: GPL-2.0 */
>> -/*
>> - * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
>> - */
>> -#ifndef _ASM_COMPILER_H
>> -#define _ASM_COMPILER_H
>> -
>> -#define GCC_OFF_SMALL_ASM() "ZC"
>> -
>> -#define LOONGARCH_ISA_LEVEL "loongarch"
>> -#define LOONGARCH_ISA_ARCH_LEVEL "arch=loongarch"
>> -#define LOONGARCH_ISA_LEVEL_RAW loongarch
>> -#define LOONGARCH_ISA_ARCH_LEVEL_RAW LOONGARCH_ISA_LEVEL_RAW
>> -
>> -#endif /* _ASM_COMPILER_H */
>> diff --git a/arch/loongarch/include/asm/futex.h b/arch/loongarch/include/asm/futex.h
>> index 9de8231694ec..e28b65d9c67a 100644
>> --- a/arch/loongarch/include/asm/futex.h
>> +++ b/arch/loongarch/include/asm/futex.h
>> @@ -8,7 +8,6 @@
>> #include <linux/futex.h>
>> #include <linux/uaccess.h>
>> #include <asm/barrier.h>
>> -#include <asm/compiler.h>
>> #include <asm/errno.h>
>>
>> #define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \
>> @@ -95,8 +94,8 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 oldval, u32 newv
>> " "__UA_ADDR "\t1b, 4b \n"
>> " "__UA_ADDR "\t2b, 4b \n"
>> " .previous \n"
>> - : "+r" (ret), "=&r" (val), "=" GCC_OFF_SMALL_ASM() (*uaddr)
>> - : GCC_OFF_SMALL_ASM() (*uaddr), "Jr" (oldval), "Jr" (newval),
>> + : "+r" (ret), "=&r" (val), "=ZC" (*uaddr)
>> + : "ZC" (*uaddr), "Jr" (oldval), "Jr" (newval),
>> "i" (-EFAULT)
>> : "memory", "t0");
>>
>> diff --git a/arch/loongarch/include/asm/irqflags.h b/arch/loongarch/include/asm/irqflags.h
>> index 52121cd791fe..319a8c616f1f 100644
>> --- a/arch/loongarch/include/asm/irqflags.h
>> +++ b/arch/loongarch/include/asm/irqflags.h
>> @@ -9,7 +9,6 @@
>>
>> #include <linux/compiler.h>
>> #include <linux/stringify.h>
>> -#include <asm/compiler.h>
>> #include <asm/loongarch.h>
>>
>> static inline void arch_local_irq_enable(void)
>> diff --git a/arch/loongarch/include/asm/local.h b/arch/loongarch/include/asm/local.h
>> index 2052a2267337..65fbbae9fc4d 100644
>> --- a/arch/loongarch/include/asm/local.h
>> +++ b/arch/loongarch/include/asm/local.h
>> @@ -9,7 +9,6 @@
>> #include <linux/bitops.h>
>> #include <linux/atomic.h>
>> #include <asm/cmpxchg.h>
>> -#include <asm/compiler.h>
>>
>> typedef struct {
>> atomic_long_t a;
>> diff --git a/arch/loongarch/kernel/reset.c b/arch/loongarch/kernel/reset.c
>> index 2b86469e4718..800c965a17ea 100644
>> --- a/arch/loongarch/kernel/reset.c
>> +++ b/arch/loongarch/kernel/reset.c
>> @@ -13,7 +13,6 @@
>> #include <linux/console.h>
>>
>> #include <acpi/reboot.h>
>> -#include <asm/compiler.h>
>> #include <asm/idle.h>
>> #include <asm/loongarch.h>
>> #include <asm/reboot.h>
>> diff --git a/arch/loongarch/lib/delay.c b/arch/loongarch/lib/delay.c
>> index 5d856694fcfe..831d4761f385 100644
>> --- a/arch/loongarch/lib/delay.c
>> +++ b/arch/loongarch/lib/delay.c
>> @@ -7,7 +7,6 @@
>> #include <linux/smp.h>
>> #include <linux/timex.h>
>>
>> -#include <asm/compiler.h>
>> #include <asm/processor.h>
>>
>> void __delay(unsigned long cycles)
>> --
>> 2.31.1
>>
>>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] LoongArch: Remove unused header compiler.h
2022-07-21 2:11 [PATCH] LoongArch: Remove unused header compiler.h Jun Yi
2022-07-21 2:52 ` Huacai Chen
@ 2022-07-21 3:20 ` WANG Xuerui
1 sibling, 0 replies; 7+ messages in thread
From: WANG Xuerui @ 2022-07-21 3:20 UTC (permalink / raw)
To: Jun Yi, Huacai Chen; +Cc: WANG Xuerui, loongarch, linux-kernel, Jiaxun Yang
On 2022/7/21 10:11, Jun Yi wrote:
> Loongarch not used arch-specific compiler.h
Of course this is wrong. There are definitely #include's of this file,
so it is definitely used.
Here's my take: "The content of loongarch's compiler.h is trivial, with
some unused anywhere, so inline the definitions and remove the header."
>
> Signed-off-by: Jun Yi <yijun@loongson.cn>
> ---
> arch/loongarch/Kconfig | 1 -
> arch/loongarch/include/asm/atomic.h | 9 ++++-----
> arch/loongarch/include/asm/compiler.h | 15 ---------------
> arch/loongarch/include/asm/futex.h | 5 ++---
> arch/loongarch/include/asm/irqflags.h | 1 -
> arch/loongarch/include/asm/local.h | 1 -
> arch/loongarch/kernel/reset.c | 1 -
> arch/loongarch/lib/delay.c | 1 -
> 8 files changed, 6 insertions(+), 28 deletions(-)
> delete mode 100644 arch/loongarch/include/asm/compiler.h
>
> diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
> index 53a912befb62..89da3e09084e 100644
> --- a/arch/loongarch/Kconfig
> +++ b/arch/loongarch/Kconfig
> @@ -69,7 +69,6 @@ config LOONGARCH
> select GENERIC_TIME_VSYSCALL
> select GPIOLIB
> select HAVE_ARCH_AUDITSYSCALL
> - select HAVE_ARCH_COMPILER_H
> select HAVE_ARCH_MMAP_RND_BITS if MMU
> select HAVE_ARCH_SECCOMP_FILTER
> select HAVE_ARCH_TRACEHOOK
> diff --git a/arch/loongarch/include/asm/atomic.h b/arch/loongarch/include/asm/atomic.h
> index 979367ad4e2c..b5e2e3201af1 100644
> --- a/arch/loongarch/include/asm/atomic.h
> +++ b/arch/loongarch/include/asm/atomic.h
> @@ -10,7 +10,6 @@
> #include <linux/types.h>
> #include <asm/barrier.h>
> #include <asm/cmpxchg.h>
> -#include <asm/compiler.h>
>
> #if __SIZEOF_LONG__ == 4
> #define __LL "ll.w "
> @@ -164,7 +163,7 @@ static inline int arch_atomic_sub_if_positive(int i, atomic_t *v)
> "2: \n"
> __WEAK_LLSC_MB
> : "=&r" (result), "=&r" (temp),
> - "+" GCC_OFF_SMALL_ASM() (v->counter)
> + "+ZC" (v->counter)
> : "I" (-i));
> } else {
> __asm__ __volatile__(
> @@ -177,7 +176,7 @@ static inline int arch_atomic_sub_if_positive(int i, atomic_t *v)
> "2: \n"
> __WEAK_LLSC_MB
> : "=&r" (result), "=&r" (temp),
> - "+" GCC_OFF_SMALL_ASM() (v->counter)
> + "+ZC" (v->counter)
> : "r" (i));
> }
>
> @@ -327,7 +326,7 @@ static inline long arch_atomic64_sub_if_positive(long i, atomic64_t *v)
> "2: \n"
> __WEAK_LLSC_MB
> : "=&r" (result), "=&r" (temp),
> - "+" GCC_OFF_SMALL_ASM() (v->counter)
> + "+ZC" (v->counter)
> : "I" (-i));
> } else {
> __asm__ __volatile__(
> @@ -340,7 +339,7 @@ static inline long arch_atomic64_sub_if_positive(long i, atomic64_t *v)
> "2: \n"
> __WEAK_LLSC_MB
> : "=&r" (result), "=&r" (temp),
> - "+" GCC_OFF_SMALL_ASM() (v->counter)
> + "+ZC" (v->counter)
> : "r" (i));
> }
>
> diff --git a/arch/loongarch/include/asm/compiler.h b/arch/loongarch/include/asm/compiler.h
> deleted file mode 100644
> index 657cebe70ace..000000000000
> --- a/arch/loongarch/include/asm/compiler.h
> +++ /dev/null
> @@ -1,15 +0,0 @@
> -/* SPDX-License-Identifier: GPL-2.0 */
> -/*
> - * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
> - */
> -#ifndef _ASM_COMPILER_H
> -#define _ASM_COMPILER_H
> -
> -#define GCC_OFF_SMALL_ASM() "ZC"
> -
> -#define LOONGARCH_ISA_LEVEL "loongarch"
> -#define LOONGARCH_ISA_ARCH_LEVEL "arch=loongarch"
> -#define LOONGARCH_ISA_LEVEL_RAW loongarch
> -#define LOONGARCH_ISA_ARCH_LEVEL_RAW LOONGARCH_ISA_LEVEL_RAW
> -
> -#endif /* _ASM_COMPILER_H */
> diff --git a/arch/loongarch/include/asm/futex.h b/arch/loongarch/include/asm/futex.h
> index 9de8231694ec..e28b65d9c67a 100644
> --- a/arch/loongarch/include/asm/futex.h
> +++ b/arch/loongarch/include/asm/futex.h
> @@ -8,7 +8,6 @@
> #include <linux/futex.h>
> #include <linux/uaccess.h>
> #include <asm/barrier.h>
> -#include <asm/compiler.h>
> #include <asm/errno.h>
>
> #define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \
> @@ -95,8 +94,8 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 oldval, u32 newv
> " "__UA_ADDR "\t1b, 4b \n"
> " "__UA_ADDR "\t2b, 4b \n"
> " .previous \n"
> - : "+r" (ret), "=&r" (val), "=" GCC_OFF_SMALL_ASM() (*uaddr)
> - : GCC_OFF_SMALL_ASM() (*uaddr), "Jr" (oldval), "Jr" (newval),
> + : "+r" (ret), "=&r" (val), "=ZC" (*uaddr)
> + : "ZC" (*uaddr), "Jr" (oldval), "Jr" (newval),
> "i" (-EFAULT)
> : "memory", "t0");
>
> diff --git a/arch/loongarch/include/asm/irqflags.h b/arch/loongarch/include/asm/irqflags.h
> index 52121cd791fe..319a8c616f1f 100644
> --- a/arch/loongarch/include/asm/irqflags.h
> +++ b/arch/loongarch/include/asm/irqflags.h
> @@ -9,7 +9,6 @@
>
> #include <linux/compiler.h>
> #include <linux/stringify.h>
> -#include <asm/compiler.h>
> #include <asm/loongarch.h>
>
> static inline void arch_local_irq_enable(void)
> diff --git a/arch/loongarch/include/asm/local.h b/arch/loongarch/include/asm/local.h
> index 2052a2267337..65fbbae9fc4d 100644
> --- a/arch/loongarch/include/asm/local.h
> +++ b/arch/loongarch/include/asm/local.h
> @@ -9,7 +9,6 @@
> #include <linux/bitops.h>
> #include <linux/atomic.h>
> #include <asm/cmpxchg.h>
> -#include <asm/compiler.h>
>
> typedef struct {
> atomic_long_t a;
> diff --git a/arch/loongarch/kernel/reset.c b/arch/loongarch/kernel/reset.c
> index 2b86469e4718..800c965a17ea 100644
> --- a/arch/loongarch/kernel/reset.c
> +++ b/arch/loongarch/kernel/reset.c
> @@ -13,7 +13,6 @@
> #include <linux/console.h>
>
> #include <acpi/reboot.h>
> -#include <asm/compiler.h>
> #include <asm/idle.h>
> #include <asm/loongarch.h>
> #include <asm/reboot.h>
> diff --git a/arch/loongarch/lib/delay.c b/arch/loongarch/lib/delay.c
> index 5d856694fcfe..831d4761f385 100644
> --- a/arch/loongarch/lib/delay.c
> +++ b/arch/loongarch/lib/delay.c
> @@ -7,7 +7,6 @@
> #include <linux/smp.h>
> #include <linux/timex.h>
>
> -#include <asm/compiler.h>
> #include <asm/processor.h>
>
> void __delay(unsigned long cycles)
The rest looks good.
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] LoongArch: Remove unused header compiler.h
2022-07-21 3:17 ` WANG Xuerui
@ 2022-07-21 3:22 ` Huacai Chen
2022-07-21 5:38 ` WANG Xuerui
0 siblings, 1 reply; 7+ messages in thread
From: Huacai Chen @ 2022-07-21 3:22 UTC (permalink / raw)
To: WANG Xuerui; +Cc: Jun Yi, loongarch, LKML, Jiaxun Yang
Hi, Xuerui,
On Thu, Jul 21, 2022 at 11:17 AM WANG Xuerui <kernel@xen0n.name> wrote:
>
> Hi YI Jun and Huacai,
>
> On 2022/7/21 10:52, Huacai Chen wrote:
> > Hi, Jun,
> >
> > On Thu, Jul 21, 2022 at 10:11 AM Jun Yi <yijun@loongson.cn> wrote:
> >> Loongarch not used arch-specific compiler.h
> > I'm not sure whether compiler.h will be used in future. If it will be
> > used, I want to keep it as is. Xuerui, what do you think about it?
>
> I surveyed all the existing arch compiler.h in the tree:
>
> $ find ./arch -name compiler.h
> ./arch/alpha/include/asm/compiler.h
> ./arch/alpha/include/uapi/asm/compiler.h
> ./arch/arm/include/asm/compiler.h
> ./arch/arm64/include/asm/compiler.h
> ./arch/mips/include/asm/compiler.h
> ./arch/loongarch/include/asm/compiler.h
>
> Of all these occurrences:
>
> - alpha needs to ensure a certain insn is being emitted from time to
> time, with plain C constructs (or built-ins) on compiler versions with
> said support, falling back to inline asm otherwise;
> - arm and arm64 both need some inline assembly help (of different sort),
> with arm64 stuffing some pointer authentication helpers into this file too;
> - mips, which is obviously what the loongarch version is based on, needs
> (1) a kludge for older compilers to fix delay slot filling around
> __builtin_unreachable, (2) definitions for explicit arch level
> selection. There is also the historical GCC_OFF_SMALL_ASM() constraint
> definition that was rendered redundant by commit 4abaacc704729 ("MIPS:
> remove GCC < 4.9 support").
>
> For loongarch, the "ZC" constraint (I don't think it was a coincidence
> BTW) should be usable for all present and future hardware, so I do think
> the GCC_OFF_SMALL_ASM() here is redundant. We may want to remove the
> mips one too. And the arch level thing is not currently needed either,
> future revisions to the LoongArch ISA should be largely backwards
> compatible, so it could be a long time before such explicit selection of
> arch level is necessary, for exact control over emitted insn.
>
> So overall, I'm in favor of removing this header for now.
Have you considered the new relocation types will be added in the near
future? I think we need compiler.h at that time.
Huacai
>
> > Huacai
> >> Signed-off-by: Jun Yi <yijun@loongson.cn>
> >> ---
> >> arch/loongarch/Kconfig | 1 -
> >> arch/loongarch/include/asm/atomic.h | 9 ++++-----
> >> arch/loongarch/include/asm/compiler.h | 15 ---------------
> >> arch/loongarch/include/asm/futex.h | 5 ++---
> >> arch/loongarch/include/asm/irqflags.h | 1 -
> >> arch/loongarch/include/asm/local.h | 1 -
> >> arch/loongarch/kernel/reset.c | 1 -
> >> arch/loongarch/lib/delay.c | 1 -
> >> 8 files changed, 6 insertions(+), 28 deletions(-)
> >> delete mode 100644 arch/loongarch/include/asm/compiler.h
> >>
> >> diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
> >> index 53a912befb62..89da3e09084e 100644
> >> --- a/arch/loongarch/Kconfig
> >> +++ b/arch/loongarch/Kconfig
> >> @@ -69,7 +69,6 @@ config LOONGARCH
> >> select GENERIC_TIME_VSYSCALL
> >> select GPIOLIB
> >> select HAVE_ARCH_AUDITSYSCALL
> >> - select HAVE_ARCH_COMPILER_H
> >> select HAVE_ARCH_MMAP_RND_BITS if MMU
> >> select HAVE_ARCH_SECCOMP_FILTER
> >> select HAVE_ARCH_TRACEHOOK
> >> diff --git a/arch/loongarch/include/asm/atomic.h b/arch/loongarch/include/asm/atomic.h
> >> index 979367ad4e2c..b5e2e3201af1 100644
> >> --- a/arch/loongarch/include/asm/atomic.h
> >> +++ b/arch/loongarch/include/asm/atomic.h
> >> @@ -10,7 +10,6 @@
> >> #include <linux/types.h>
> >> #include <asm/barrier.h>
> >> #include <asm/cmpxchg.h>
> >> -#include <asm/compiler.h>
> >>
> >> #if __SIZEOF_LONG__ == 4
> >> #define __LL "ll.w "
> >> @@ -164,7 +163,7 @@ static inline int arch_atomic_sub_if_positive(int i, atomic_t *v)
> >> "2: \n"
> >> __WEAK_LLSC_MB
> >> : "=&r" (result), "=&r" (temp),
> >> - "+" GCC_OFF_SMALL_ASM() (v->counter)
> >> + "+ZC" (v->counter)
> >> : "I" (-i));
> >> } else {
> >> __asm__ __volatile__(
> >> @@ -177,7 +176,7 @@ static inline int arch_atomic_sub_if_positive(int i, atomic_t *v)
> >> "2: \n"
> >> __WEAK_LLSC_MB
> >> : "=&r" (result), "=&r" (temp),
> >> - "+" GCC_OFF_SMALL_ASM() (v->counter)
> >> + "+ZC" (v->counter)
> >> : "r" (i));
> >> }
> >>
> >> @@ -327,7 +326,7 @@ static inline long arch_atomic64_sub_if_positive(long i, atomic64_t *v)
> >> "2: \n"
> >> __WEAK_LLSC_MB
> >> : "=&r" (result), "=&r" (temp),
> >> - "+" GCC_OFF_SMALL_ASM() (v->counter)
> >> + "+ZC" (v->counter)
> >> : "I" (-i));
> >> } else {
> >> __asm__ __volatile__(
> >> @@ -340,7 +339,7 @@ static inline long arch_atomic64_sub_if_positive(long i, atomic64_t *v)
> >> "2: \n"
> >> __WEAK_LLSC_MB
> >> : "=&r" (result), "=&r" (temp),
> >> - "+" GCC_OFF_SMALL_ASM() (v->counter)
> >> + "+ZC" (v->counter)
> >> : "r" (i));
> >> }
> >>
> >> diff --git a/arch/loongarch/include/asm/compiler.h b/arch/loongarch/include/asm/compiler.h
> >> deleted file mode 100644
> >> index 657cebe70ace..000000000000
> >> --- a/arch/loongarch/include/asm/compiler.h
> >> +++ /dev/null
> >> @@ -1,15 +0,0 @@
> >> -/* SPDX-License-Identifier: GPL-2.0 */
> >> -/*
> >> - * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
> >> - */
> >> -#ifndef _ASM_COMPILER_H
> >> -#define _ASM_COMPILER_H
> >> -
> >> -#define GCC_OFF_SMALL_ASM() "ZC"
> >> -
> >> -#define LOONGARCH_ISA_LEVEL "loongarch"
> >> -#define LOONGARCH_ISA_ARCH_LEVEL "arch=loongarch"
> >> -#define LOONGARCH_ISA_LEVEL_RAW loongarch
> >> -#define LOONGARCH_ISA_ARCH_LEVEL_RAW LOONGARCH_ISA_LEVEL_RAW
> >> -
> >> -#endif /* _ASM_COMPILER_H */
> >> diff --git a/arch/loongarch/include/asm/futex.h b/arch/loongarch/include/asm/futex.h
> >> index 9de8231694ec..e28b65d9c67a 100644
> >> --- a/arch/loongarch/include/asm/futex.h
> >> +++ b/arch/loongarch/include/asm/futex.h
> >> @@ -8,7 +8,6 @@
> >> #include <linux/futex.h>
> >> #include <linux/uaccess.h>
> >> #include <asm/barrier.h>
> >> -#include <asm/compiler.h>
> >> #include <asm/errno.h>
> >>
> >> #define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \
> >> @@ -95,8 +94,8 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 oldval, u32 newv
> >> " "__UA_ADDR "\t1b, 4b \n"
> >> " "__UA_ADDR "\t2b, 4b \n"
> >> " .previous \n"
> >> - : "+r" (ret), "=&r" (val), "=" GCC_OFF_SMALL_ASM() (*uaddr)
> >> - : GCC_OFF_SMALL_ASM() (*uaddr), "Jr" (oldval), "Jr" (newval),
> >> + : "+r" (ret), "=&r" (val), "=ZC" (*uaddr)
> >> + : "ZC" (*uaddr), "Jr" (oldval), "Jr" (newval),
> >> "i" (-EFAULT)
> >> : "memory", "t0");
> >>
> >> diff --git a/arch/loongarch/include/asm/irqflags.h b/arch/loongarch/include/asm/irqflags.h
> >> index 52121cd791fe..319a8c616f1f 100644
> >> --- a/arch/loongarch/include/asm/irqflags.h
> >> +++ b/arch/loongarch/include/asm/irqflags.h
> >> @@ -9,7 +9,6 @@
> >>
> >> #include <linux/compiler.h>
> >> #include <linux/stringify.h>
> >> -#include <asm/compiler.h>
> >> #include <asm/loongarch.h>
> >>
> >> static inline void arch_local_irq_enable(void)
> >> diff --git a/arch/loongarch/include/asm/local.h b/arch/loongarch/include/asm/local.h
> >> index 2052a2267337..65fbbae9fc4d 100644
> >> --- a/arch/loongarch/include/asm/local.h
> >> +++ b/arch/loongarch/include/asm/local.h
> >> @@ -9,7 +9,6 @@
> >> #include <linux/bitops.h>
> >> #include <linux/atomic.h>
> >> #include <asm/cmpxchg.h>
> >> -#include <asm/compiler.h>
> >>
> >> typedef struct {
> >> atomic_long_t a;
> >> diff --git a/arch/loongarch/kernel/reset.c b/arch/loongarch/kernel/reset.c
> >> index 2b86469e4718..800c965a17ea 100644
> >> --- a/arch/loongarch/kernel/reset.c
> >> +++ b/arch/loongarch/kernel/reset.c
> >> @@ -13,7 +13,6 @@
> >> #include <linux/console.h>
> >>
> >> #include <acpi/reboot.h>
> >> -#include <asm/compiler.h>
> >> #include <asm/idle.h>
> >> #include <asm/loongarch.h>
> >> #include <asm/reboot.h>
> >> diff --git a/arch/loongarch/lib/delay.c b/arch/loongarch/lib/delay.c
> >> index 5d856694fcfe..831d4761f385 100644
> >> --- a/arch/loongarch/lib/delay.c
> >> +++ b/arch/loongarch/lib/delay.c
> >> @@ -7,7 +7,6 @@
> >> #include <linux/smp.h>
> >> #include <linux/timex.h>
> >>
> >> -#include <asm/compiler.h>
> >> #include <asm/processor.h>
> >>
> >> void __delay(unsigned long cycles)
> >> --
> >> 2.31.1
> >>
> >>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] LoongArch: Remove unused header compiler.h
2022-07-21 3:22 ` Huacai Chen
@ 2022-07-21 5:38 ` WANG Xuerui
2022-07-21 8:36 ` Huacai Chen
0 siblings, 1 reply; 7+ messages in thread
From: WANG Xuerui @ 2022-07-21 5:38 UTC (permalink / raw)
To: Huacai Chen, WANG Xuerui; +Cc: Jun Yi, loongarch, LKML, Jiaxun Yang
On 2022/7/21 11:22, Huacai Chen wrote:
> Hi, Xuerui,
>
> On Thu, Jul 21, 2022 at 11:17 AM WANG Xuerui <kernel@xen0n.name> wrote:
>> Hi YI Jun and Huacai,
>>
>> On 2022/7/21 10:52, Huacai Chen wrote:
>>> Hi, Jun,
>>>
>>> On Thu, Jul 21, 2022 at 10:11 AM Jun Yi <yijun@loongson.cn> wrote:
>>>> Loongarch not used arch-specific compiler.h
>>> I'm not sure whether compiler.h will be used in future. If it will be
>>> used, I want to keep it as is. Xuerui, what do you think about it?
>> I surveyed all the existing arch compiler.h in the tree:
>>
>> $ find ./arch -name compiler.h
>> ./arch/alpha/include/asm/compiler.h
>> ./arch/alpha/include/uapi/asm/compiler.h
>> ./arch/arm/include/asm/compiler.h
>> ./arch/arm64/include/asm/compiler.h
>> ./arch/mips/include/asm/compiler.h
>> ./arch/loongarch/include/asm/compiler.h
>>
>> Of all these occurrences:
>>
>> - alpha needs to ensure a certain insn is being emitted from time to
>> time, with plain C constructs (or built-ins) on compiler versions with
>> said support, falling back to inline asm otherwise;
>> - arm and arm64 both need some inline assembly help (of different sort),
>> with arm64 stuffing some pointer authentication helpers into this file too;
>> - mips, which is obviously what the loongarch version is based on, needs
>> (1) a kludge for older compilers to fix delay slot filling around
>> __builtin_unreachable, (2) definitions for explicit arch level
>> selection. There is also the historical GCC_OFF_SMALL_ASM() constraint
>> definition that was rendered redundant by commit 4abaacc704729 ("MIPS:
>> remove GCC < 4.9 support").
>>
>> For loongarch, the "ZC" constraint (I don't think it was a coincidence
>> BTW) should be usable for all present and future hardware, so I do think
>> the GCC_OFF_SMALL_ASM() here is redundant. We may want to remove the
>> mips one too. And the arch level thing is not currently needed either,
>> future revisions to the LoongArch ISA should be largely backwards
>> compatible, so it could be a long time before such explicit selection of
>> arch level is necessary, for exact control over emitted insn.
>>
>> So overall, I'm in favor of removing this header for now.
> Have you considered the new relocation types will be added in the near
> future? I think we need compiler.h at that time.
I assume you mean the proposal being discussed at [1] [2] and [3].
For new reloc types that affect module loading, asm/elf.h and
kernel/module.c need modification to add awareness, but this doesn't
involve compiler.h. The kernel image itself is not affected.
There is also the case of building LoongArch kernel sources without
support for the new reloc types, but on a newer compiler that emits the
new-style reloc records by default. In this case, a switch reverting the
compiler to the old-style relocs is needed in CFLAGS, but (1) not all
essential support are merged for LoongArch so practically we don't need
to care about non-kernel-ABI compatibility at this time, and (2) CFLAGS
tweaks don't involve compiler.h either.
[1]: https://sourceware.org/pipermail/binutils/2022-July/121849.html
[2]: https://sourceware.org/pipermail/binutils/2022-July/121933.html
[3]: https://github.com/loongson/LoongArch-Documentation/pull/57
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] LoongArch: Remove unused header compiler.h
2022-07-21 5:38 ` WANG Xuerui
@ 2022-07-21 8:36 ` Huacai Chen
0 siblings, 0 replies; 7+ messages in thread
From: Huacai Chen @ 2022-07-21 8:36 UTC (permalink / raw)
To: WANG Xuerui; +Cc: Jun Yi, loongarch, LKML, Jiaxun Yang
OK, please update the commit message and send V2, please.
On Thu, Jul 21, 2022 at 1:38 PM WANG Xuerui <kernel@xen0n.name> wrote:
>
> On 2022/7/21 11:22, Huacai Chen wrote:
> > Hi, Xuerui,
> >
> > On Thu, Jul 21, 2022 at 11:17 AM WANG Xuerui <kernel@xen0n.name> wrote:
> >> Hi YI Jun and Huacai,
> >>
> >> On 2022/7/21 10:52, Huacai Chen wrote:
> >>> Hi, Jun,
> >>>
> >>> On Thu, Jul 21, 2022 at 10:11 AM Jun Yi <yijun@loongson.cn> wrote:
> >>>> Loongarch not used arch-specific compiler.h
> >>> I'm not sure whether compiler.h will be used in future. If it will be
> >>> used, I want to keep it as is. Xuerui, what do you think about it?
> >> I surveyed all the existing arch compiler.h in the tree:
> >>
> >> $ find ./arch -name compiler.h
> >> ./arch/alpha/include/asm/compiler.h
> >> ./arch/alpha/include/uapi/asm/compiler.h
> >> ./arch/arm/include/asm/compiler.h
> >> ./arch/arm64/include/asm/compiler.h
> >> ./arch/mips/include/asm/compiler.h
> >> ./arch/loongarch/include/asm/compiler.h
> >>
> >> Of all these occurrences:
> >>
> >> - alpha needs to ensure a certain insn is being emitted from time to
> >> time, with plain C constructs (or built-ins) on compiler versions with
> >> said support, falling back to inline asm otherwise;
> >> - arm and arm64 both need some inline assembly help (of different sort),
> >> with arm64 stuffing some pointer authentication helpers into this file too;
> >> - mips, which is obviously what the loongarch version is based on, needs
> >> (1) a kludge for older compilers to fix delay slot filling around
> >> __builtin_unreachable, (2) definitions for explicit arch level
> >> selection. There is also the historical GCC_OFF_SMALL_ASM() constraint
> >> definition that was rendered redundant by commit 4abaacc704729 ("MIPS:
> >> remove GCC < 4.9 support").
> >>
> >> For loongarch, the "ZC" constraint (I don't think it was a coincidence
> >> BTW) should be usable for all present and future hardware, so I do think
> >> the GCC_OFF_SMALL_ASM() here is redundant. We may want to remove the
> >> mips one too. And the arch level thing is not currently needed either,
> >> future revisions to the LoongArch ISA should be largely backwards
> >> compatible, so it could be a long time before such explicit selection of
> >> arch level is necessary, for exact control over emitted insn.
> >>
> >> So overall, I'm in favor of removing this header for now.
> > Have you considered the new relocation types will be added in the near
> > future? I think we need compiler.h at that time.
>
> I assume you mean the proposal being discussed at [1] [2] and [3].
>
> For new reloc types that affect module loading, asm/elf.h and
> kernel/module.c need modification to add awareness, but this doesn't
> involve compiler.h. The kernel image itself is not affected.
>
> There is also the case of building LoongArch kernel sources without
> support for the new reloc types, but on a newer compiler that emits the
> new-style reloc records by default. In this case, a switch reverting the
> compiler to the old-style relocs is needed in CFLAGS, but (1) not all
> essential support are merged for LoongArch so practically we don't need
> to care about non-kernel-ABI compatibility at this time, and (2) CFLAGS
> tweaks don't involve compiler.h either.
>
> [1]: https://sourceware.org/pipermail/binutils/2022-July/121849.html
> [2]: https://sourceware.org/pipermail/binutils/2022-July/121933.html
> [3]: https://github.com/loongson/LoongArch-Documentation/pull/57
>
>
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2022-07-21 8:36 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-07-21 2:11 [PATCH] LoongArch: Remove unused header compiler.h Jun Yi
2022-07-21 2:52 ` Huacai Chen
2022-07-21 3:17 ` WANG Xuerui
2022-07-21 3:22 ` Huacai Chen
2022-07-21 5:38 ` WANG Xuerui
2022-07-21 8:36 ` Huacai Chen
2022-07-21 3:20 ` WANG Xuerui
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