From 7193b5c4758368c3a0de0cf4fa54bc8697caaf86 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Mon, 8 Apr 2024 17:43:37 -0400 Subject: [PATCH 1/2] alpha: no need to include asm/xchg.h twice We used to generate different helpers for local and full {cmp,}xchg(); these days the barriers are in arch_{cmp,}xchg() instead and generated helpers are identical for local and full cases. No need for those parametrized includes of asm/xchg.h - we might as well insert its contents directly in asm/cmpxchg.h and do it only once. Signed-off-by: Al Viro --- arch/alpha/include/asm/cmpxchg.h | 239 ++++++++++++++++++++++++++++-- arch/alpha/include/asm/xchg.h | 246 ------------------------------- 2 files changed, 223 insertions(+), 262 deletions(-) delete mode 100644 arch/alpha/include/asm/xchg.h diff --git a/arch/alpha/include/asm/cmpxchg.h b/arch/alpha/include/asm/cmpxchg.h index 91d4a4d9258c..ae1b96479d0c 100644 --- a/arch/alpha/include/asm/cmpxchg.h +++ b/arch/alpha/include/asm/cmpxchg.h @@ -3,17 +3,232 @@ #define _ALPHA_CMPXCHG_H /* - * Atomic exchange routines. + * Atomic exchange. + * Since it can be used to implement critical sections + * it must clobber "memory" (also for interrupts in UP). */ -#define ____xchg(type, args...) __arch_xchg ## type ## _local(args) -#define ____cmpxchg(type, args...) __cmpxchg ## type ## _local(args) -#include +static inline unsigned long +____xchg_u8(volatile char *m, unsigned long val) +{ + unsigned long ret, tmp, addr64; + + __asm__ __volatile__( + " andnot %4,7,%3\n" + " insbl %1,%4,%1\n" + "1: ldq_l %2,0(%3)\n" + " extbl %2,%4,%0\n" + " mskbl %2,%4,%2\n" + " or %1,%2,%2\n" + " stq_c %2,0(%3)\n" + " beq %2,2f\n" + ".subsection 2\n" + "2: br 1b\n" + ".previous" + : "=&r" (ret), "=&r" (val), "=&r" (tmp), "=&r" (addr64) + : "r" ((long)m), "1" (val) : "memory"); + + return ret; +} + +static inline unsigned long +____xchg_u16(volatile short *m, unsigned long val) +{ + unsigned long ret, tmp, addr64; + + __asm__ __volatile__( + " andnot %4,7,%3\n" + " inswl %1,%4,%1\n" + "1: ldq_l %2,0(%3)\n" + " extwl %2,%4,%0\n" + " mskwl %2,%4,%2\n" + " or %1,%2,%2\n" + " stq_c %2,0(%3)\n" + " beq %2,2f\n" + ".subsection 2\n" + "2: br 1b\n" + ".previous" + : "=&r" (ret), "=&r" (val), "=&r" (tmp), "=&r" (addr64) + : "r" ((long)m), "1" (val) : "memory"); + + return ret; +} + +static inline unsigned long +____xchg_u32(volatile int *m, unsigned long val) +{ + unsigned long dummy; + + __asm__ __volatile__( + "1: ldl_l %0,%4\n" + " bis $31,%3,%1\n" + " stl_c %1,%2\n" + " beq %1,2f\n" + ".subsection 2\n" + "2: br 1b\n" + ".previous" + : "=&r" (val), "=&r" (dummy), "=m" (*m) + : "rI" (val), "m" (*m) : "memory"); + + return val; +} + +static inline unsigned long +____xchg_u64(volatile long *m, unsigned long val) +{ + unsigned long dummy; + + __asm__ __volatile__( + "1: ldq_l %0,%4\n" + " bis $31,%3,%1\n" + " stq_c %1,%2\n" + " beq %1,2f\n" + ".subsection 2\n" + "2: br 1b\n" + ".previous" + : "=&r" (val), "=&r" (dummy), "=m" (*m) + : "rI" (val), "m" (*m) : "memory"); + + return val; +} + +/* This function doesn't exist, so you'll get a linker error + if something tries to do an invalid xchg(). */ +extern void __xchg_called_with_bad_pointer(void); + +static __always_inline unsigned long +____xchg(volatile void *ptr, unsigned long x, int size) +{ + return + size == 1 ? ____xchg_u8(ptr, x) : + size == 2 ? ____xchg_u16(ptr, x) : + size == 4 ? ____xchg_u32(ptr, x) : + size == 8 ? ____xchg_u64(ptr, x) : + (__xchg_called_with_bad_pointer(), x); +} + +/* + * Atomic compare and exchange. Compare OLD with MEM, if identical, + * store NEW in MEM. Return the initial value in MEM. Success is + * indicated by comparing RETURN with OLD. + */ + +static inline unsigned long +____cmpxchg_u8(volatile char *m, unsigned char old, unsigned char new) +{ + unsigned long prev, tmp, cmp, addr64; + + __asm__ __volatile__( + " andnot %5,7,%4\n" + " insbl %1,%5,%1\n" + "1: ldq_l %2,0(%4)\n" + " extbl %2,%5,%0\n" + " cmpeq %0,%6,%3\n" + " beq %3,2f\n" + " mskbl %2,%5,%2\n" + " or %1,%2,%2\n" + " stq_c %2,0(%4)\n" + " beq %2,3f\n" + "2:\n" + ".subsection 2\n" + "3: br 1b\n" + ".previous" + : "=&r" (prev), "=&r" (new), "=&r" (tmp), "=&r" (cmp), "=&r" (addr64) + : "r" ((long)m), "Ir" (old), "1" (new) : "memory"); + + return prev; +} + +static inline unsigned long +____cmpxchg_u16(volatile short *m, unsigned short old, unsigned short new) +{ + unsigned long prev, tmp, cmp, addr64; + + __asm__ __volatile__( + " andnot %5,7,%4\n" + " inswl %1,%5,%1\n" + "1: ldq_l %2,0(%4)\n" + " extwl %2,%5,%0\n" + " cmpeq %0,%6,%3\n" + " beq %3,2f\n" + " mskwl %2,%5,%2\n" + " or %1,%2,%2\n" + " stq_c %2,0(%4)\n" + " beq %2,3f\n" + "2:\n" + ".subsection 2\n" + "3: br 1b\n" + ".previous" + : "=&r" (prev), "=&r" (new), "=&r" (tmp), "=&r" (cmp), "=&r" (addr64) + : "r" ((long)m), "Ir" (old), "1" (new) : "memory"); + + return prev; +} + +static inline unsigned long +____cmpxchg_u32(volatile int *m, int old, int new) +{ + unsigned long prev, cmp; + + __asm__ __volatile__( + "1: ldl_l %0,%5\n" + " cmpeq %0,%3,%1\n" + " beq %1,2f\n" + " mov %4,%1\n" + " stl_c %1,%2\n" + " beq %1,3f\n" + "2:\n" + ".subsection 2\n" + "3: br 1b\n" + ".previous" + : "=&r"(prev), "=&r"(cmp), "=m"(*m) + : "r"((long) old), "r"(new), "m"(*m) : "memory"); + + return prev; +} + +static inline unsigned long +____cmpxchg_u64(volatile long *m, unsigned long old, unsigned long new) +{ + unsigned long prev, cmp; + + __asm__ __volatile__( + "1: ldq_l %0,%5\n" + " cmpeq %0,%3,%1\n" + " beq %1,2f\n" + " mov %4,%1\n" + " stq_c %1,%2\n" + " beq %1,3f\n" + "2:\n" + ".subsection 2\n" + "3: br 1b\n" + ".previous" + : "=&r"(prev), "=&r"(cmp), "=m"(*m) + : "r"((long) old), "r"(new), "m"(*m) : "memory"); + + return prev; +} + +/* This function doesn't exist, so you'll get a linker error + if something tries to do an invalid cmpxchg(). */ +extern void __cmpxchg_called_with_bad_pointer(void); + +static __always_inline unsigned long +____cmpxchg(volatile void *ptr, unsigned long old, unsigned long new, + int size) +{ + return + size == 1 ? ____cmpxchg_u8(ptr, old, new) : + size == 2 ? ____cmpxchg_u16(ptr, old, new) : + size == 4 ? ____cmpxchg_u32(ptr, old, new) : + size == 8 ? ____cmpxchg_u64(ptr, old, new) : + (__cmpxchg_called_with_bad_pointer(), old); +} #define xchg_local(ptr, x) \ ({ \ __typeof__(*(ptr)) _x_ = (x); \ - (__typeof__(*(ptr))) __arch_xchg_local((ptr), (unsigned long)_x_,\ + (__typeof__(*(ptr))) ____xchg((ptr), (unsigned long)_x_, \ sizeof(*(ptr))); \ }) @@ -21,7 +236,7 @@ ({ \ __typeof__(*(ptr)) _o_ = (o); \ __typeof__(*(ptr)) _n_ = (n); \ - (__typeof__(*(ptr))) __cmpxchg_local((ptr), (unsigned long)_o_, \ + (__typeof__(*(ptr))) ____cmpxchg((ptr), (unsigned long)_o_, \ (unsigned long)_n_, \ sizeof(*(ptr))); \ }) @@ -32,12 +247,6 @@ cmpxchg_local((ptr), (o), (n)); \ }) -#undef ____xchg -#undef ____cmpxchg -#define ____xchg(type, args...) __arch_xchg ##type(args) -#define ____cmpxchg(type, args...) __cmpxchg ##type(args) -#include - /* * The leading and the trailing memory barriers guarantee that these * operations are fully ordered. @@ -48,7 +257,7 @@ __typeof__(*(ptr)) _x_ = (x); \ smp_mb(); \ __ret = (__typeof__(*(ptr))) \ - __arch_xchg((ptr), (unsigned long)_x_, sizeof(*(ptr))); \ + ____xchg((ptr), (unsigned long)_x_, sizeof(*(ptr))); \ smp_mb(); \ __ret; \ }) @@ -59,7 +268,7 @@ __typeof__(*(ptr)) _o_ = (o); \ __typeof__(*(ptr)) _n_ = (n); \ smp_mb(); \ - __ret = (__typeof__(*(ptr))) __cmpxchg((ptr), \ + __ret = (__typeof__(*(ptr))) ____cmpxchg((ptr), \ (unsigned long)_o_, (unsigned long)_n_, sizeof(*(ptr)));\ smp_mb(); \ __ret; \ @@ -71,6 +280,4 @@ arch_cmpxchg((ptr), (o), (n)); \ }) -#undef ____cmpxchg - #endif /* _ALPHA_CMPXCHG_H */ diff --git a/arch/alpha/include/asm/xchg.h b/arch/alpha/include/asm/xchg.h deleted file mode 100644 index 7adb80c6746a..000000000000 --- a/arch/alpha/include/asm/xchg.h +++ /dev/null @@ -1,246 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0 */ -#ifndef _ALPHA_CMPXCHG_H -#error Do not include xchg.h directly! -#else -/* - * xchg/xchg_local and cmpxchg/cmpxchg_local share the same code - * except that local version do not have the expensive memory barrier. - * So this file is included twice from asm/cmpxchg.h. - */ - -/* - * Atomic exchange. - * Since it can be used to implement critical sections - * it must clobber "memory" (also for interrupts in UP). - */ - -static inline unsigned long -____xchg(_u8, volatile char *m, unsigned long val) -{ - unsigned long ret, tmp, addr64; - - __asm__ __volatile__( - " andnot %4,7,%3\n" - " insbl %1,%4,%1\n" - "1: ldq_l %2,0(%3)\n" - " extbl %2,%4,%0\n" - " mskbl %2,%4,%2\n" - " or %1,%2,%2\n" - " stq_c %2,0(%3)\n" - " beq %2,2f\n" - ".subsection 2\n" - "2: br 1b\n" - ".previous" - : "=&r" (ret), "=&r" (val), "=&r" (tmp), "=&r" (addr64) - : "r" ((long)m), "1" (val) : "memory"); - - return ret; -} - -static inline unsigned long -____xchg(_u16, volatile short *m, unsigned long val) -{ - unsigned long ret, tmp, addr64; - - __asm__ __volatile__( - " andnot %4,7,%3\n" - " inswl %1,%4,%1\n" - "1: ldq_l %2,0(%3)\n" - " extwl %2,%4,%0\n" - " mskwl %2,%4,%2\n" - " or %1,%2,%2\n" - " stq_c %2,0(%3)\n" - " beq %2,2f\n" - ".subsection 2\n" - "2: br 1b\n" - ".previous" - : "=&r" (ret), "=&r" (val), "=&r" (tmp), "=&r" (addr64) - : "r" ((long)m), "1" (val) : "memory"); - - return ret; -} - -static inline unsigned long -____xchg(_u32, volatile int *m, unsigned long val) -{ - unsigned long dummy; - - __asm__ __volatile__( - "1: ldl_l %0,%4\n" - " bis $31,%3,%1\n" - " stl_c %1,%2\n" - " beq %1,2f\n" - ".subsection 2\n" - "2: br 1b\n" - ".previous" - : "=&r" (val), "=&r" (dummy), "=m" (*m) - : "rI" (val), "m" (*m) : "memory"); - - return val; -} - -static inline unsigned long -____xchg(_u64, volatile long *m, unsigned long val) -{ - unsigned long dummy; - - __asm__ __volatile__( - "1: ldq_l %0,%4\n" - " bis $31,%3,%1\n" - " stq_c %1,%2\n" - " beq %1,2f\n" - ".subsection 2\n" - "2: br 1b\n" - ".previous" - : "=&r" (val), "=&r" (dummy), "=m" (*m) - : "rI" (val), "m" (*m) : "memory"); - - return val; -} - -/* This function doesn't exist, so you'll get a linker error - if something tries to do an invalid xchg(). */ -extern void __xchg_called_with_bad_pointer(void); - -static __always_inline unsigned long -____xchg(, volatile void *ptr, unsigned long x, int size) -{ - switch (size) { - case 1: - return ____xchg(_u8, ptr, x); - case 2: - return ____xchg(_u16, ptr, x); - case 4: - return ____xchg(_u32, ptr, x); - case 8: - return ____xchg(_u64, ptr, x); - } - __xchg_called_with_bad_pointer(); - return x; -} - -/* - * Atomic compare and exchange. Compare OLD with MEM, if identical, - * store NEW in MEM. Return the initial value in MEM. Success is - * indicated by comparing RETURN with OLD. - */ - -static inline unsigned long -____cmpxchg(_u8, volatile char *m, unsigned char old, unsigned char new) -{ - unsigned long prev, tmp, cmp, addr64; - - __asm__ __volatile__( - " andnot %5,7,%4\n" - " insbl %1,%5,%1\n" - "1: ldq_l %2,0(%4)\n" - " extbl %2,%5,%0\n" - " cmpeq %0,%6,%3\n" - " beq %3,2f\n" - " mskbl %2,%5,%2\n" - " or %1,%2,%2\n" - " stq_c %2,0(%4)\n" - " beq %2,3f\n" - "2:\n" - ".subsection 2\n" - "3: br 1b\n" - ".previous" - : "=&r" (prev), "=&r" (new), "=&r" (tmp), "=&r" (cmp), "=&r" (addr64) - : "r" ((long)m), "Ir" (old), "1" (new) : "memory"); - - return prev; -} - -static inline unsigned long -____cmpxchg(_u16, volatile short *m, unsigned short old, unsigned short new) -{ - unsigned long prev, tmp, cmp, addr64; - - __asm__ __volatile__( - " andnot %5,7,%4\n" - " inswl %1,%5,%1\n" - "1: ldq_l %2,0(%4)\n" - " extwl %2,%5,%0\n" - " cmpeq %0,%6,%3\n" - " beq %3,2f\n" - " mskwl %2,%5,%2\n" - " or %1,%2,%2\n" - " stq_c %2,0(%4)\n" - " beq %2,3f\n" - "2:\n" - ".subsection 2\n" - "3: br 1b\n" - ".previous" - : "=&r" (prev), "=&r" (new), "=&r" (tmp), "=&r" (cmp), "=&r" (addr64) - : "r" ((long)m), "Ir" (old), "1" (new) : "memory"); - - return prev; -} - -static inline unsigned long -____cmpxchg(_u32, volatile int *m, int old, int new) -{ - unsigned long prev, cmp; - - __asm__ __volatile__( - "1: ldl_l %0,%5\n" - " cmpeq %0,%3,%1\n" - " beq %1,2f\n" - " mov %4,%1\n" - " stl_c %1,%2\n" - " beq %1,3f\n" - "2:\n" - ".subsection 2\n" - "3: br 1b\n" - ".previous" - : "=&r"(prev), "=&r"(cmp), "=m"(*m) - : "r"((long) old), "r"(new), "m"(*m) : "memory"); - - return prev; -} - -static inline unsigned long -____cmpxchg(_u64, volatile long *m, unsigned long old, unsigned long new) -{ - unsigned long prev, cmp; - - __asm__ __volatile__( - "1: ldq_l %0,%5\n" - " cmpeq %0,%3,%1\n" - " beq %1,2f\n" - " mov %4,%1\n" - " stq_c %1,%2\n" - " beq %1,3f\n" - "2:\n" - ".subsection 2\n" - "3: br 1b\n" - ".previous" - : "=&r"(prev), "=&r"(cmp), "=m"(*m) - : "r"((long) old), "r"(new), "m"(*m) : "memory"); - - return prev; -} - -/* This function doesn't exist, so you'll get a linker error - if something tries to do an invalid cmpxchg(). */ -extern void __cmpxchg_called_with_bad_pointer(void); - -static __always_inline unsigned long -____cmpxchg(, volatile void *ptr, unsigned long old, unsigned long new, - int size) -{ - switch (size) { - case 1: - return ____cmpxchg(_u8, ptr, old, new); - case 2: - return ____cmpxchg(_u16, ptr, old, new); - case 4: - return ____cmpxchg(_u32, ptr, old, new); - case 8: - return ____cmpxchg(_u64, ptr, old, new); - } - __cmpxchg_called_with_bad_pointer(); - return old; -} - -#endif From 92a10d3861491d09e73b35db7113dd049659f588 Mon Sep 17 00:00:00 2001 From: Jann Horn Date: Tue, 30 Jul 2024 22:15:16 +0200 Subject: [PATCH 2/2] runtime constants: move list of constants to vmlinux.lds.h Refactor the list of constant variables into a macro. This should make it easier to add more constants in the future. Signed-off-by: Jann Horn Reviewed-by: Alexander Gordeev Reviewed-by: Thomas Gleixner Acked-by: Arnd Bergmann Acked-by: Will Deacon Signed-off-by: Arnd Bergmann --- arch/arm64/kernel/vmlinux.lds.S | 3 +-- arch/s390/kernel/vmlinux.lds.S | 3 +-- arch/x86/kernel/vmlinux.lds.S | 3 +-- include/asm-generic/vmlinux.lds.h | 4 ++++ 4 files changed, 7 insertions(+), 6 deletions(-) diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S index 55a8e310ea12..58d89d997d05 100644 --- a/arch/arm64/kernel/vmlinux.lds.S +++ b/arch/arm64/kernel/vmlinux.lds.S @@ -264,8 +264,7 @@ SECTIONS EXIT_DATA } - RUNTIME_CONST(shift, d_hash_shift) - RUNTIME_CONST(ptr, dentry_hashtable) + RUNTIME_CONST_VARIABLES PERCPU_SECTION(L1_CACHE_BYTES) HYPERVISOR_PERCPU_SECTION diff --git a/arch/s390/kernel/vmlinux.lds.S b/arch/s390/kernel/vmlinux.lds.S index e67cd409b858..5e2e44596975 100644 --- a/arch/s390/kernel/vmlinux.lds.S +++ b/arch/s390/kernel/vmlinux.lds.S @@ -191,8 +191,7 @@ SECTIONS . = ALIGN(PAGE_SIZE); INIT_DATA_SECTION(0x100) - RUNTIME_CONST(shift, d_hash_shift) - RUNTIME_CONST(ptr, dentry_hashtable) + RUNTIME_CONST_VARIABLES PERCPU_SECTION(0x100) diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index 6e73403e874f..6726be89b7a6 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -357,8 +357,7 @@ SECTIONS PERCPU_SECTION(INTERNODE_CACHE_BYTES) #endif - RUNTIME_CONST(shift, d_hash_shift) - RUNTIME_CONST(ptr, dentry_hashtable) + RUNTIME_CONST_VARIABLES . = ALIGN(PAGE_SIZE); diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index 1ae44793132a..2157d8802351 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -918,6 +918,10 @@ #define RUNTIME_CONST(t,x) NAMED_SECTION(runtime_##t##_##x) +#define RUNTIME_CONST_VARIABLES \ + RUNTIME_CONST(shift, d_hash_shift) \ + RUNTIME_CONST(ptr, dentry_hashtable) + /* Alignment must be consistent with (kunit_suite *) in include/kunit/test.h */ #define KUNIT_TABLE() \ . = ALIGN(8); \