Messages in this thread | | | From | Huacai Chen <> | Date | Thu, 21 Jul 2022 11:22:47 +0800 | Subject | Re: [PATCH] LoongArch: Remove unused header compiler.h |
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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 > >> > >>
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