diff options
author | Tejun Heo <tj@kernel.org> | 2009-01-13 20:41:35 +0900 |
---|---|---|
committer | Ingo Molnar <mingo@elte.hu> | 2009-01-16 14:19:58 +0100 |
commit | 9939ddaff52787b2a7c1adf1b2afc95421aa0884 (patch) | |
tree | 6e7266d065914e19c3c3f4b4e475f09b9669fa51 /arch/x86/include/asm | |
parent | 1a51e3a0aed18767cf2762e95456ecfeb0bca5e6 (diff) |
x86: merge 64 and 32 SMP percpu handling
Now that pda is allocated as part of percpu, percpu doesn't need to be
accessed through pda. Unify x86_64 SMP percpu access with x86_32 SMP
one. Other than the segment register, operand size and the base of
percpu symbols, they behave identical now.
This patch replaces now unnecessary pda->data_offset with a dummy
field which is necessary to keep stack_canary at its place. This
patch also moves per_cpu_offset initialization out of init_gdt() into
setup_per_cpu_areas(). Note that this change also necessitates
explicit per_cpu_offset initializations in voyager_smp.c.
With this change, x86_OP_percpu()'s are as efficient on x86_64 as on
x86_32 and also x86_64 can use assembly PER_CPU macros.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/include/asm')
-rw-r--r-- | arch/x86/include/asm/pda.h | 3 | ||||
-rw-r--r-- | arch/x86/include/asm/percpu.h | 127 |
2 files changed, 40 insertions, 90 deletions
diff --git a/arch/x86/include/asm/pda.h b/arch/x86/include/asm/pda.h index 2d5b49c3248..e91558e3785 100644 --- a/arch/x86/include/asm/pda.h +++ b/arch/x86/include/asm/pda.h @@ -11,8 +11,7 @@ /* Per processor datastructure. %gs points to it while the kernel runs */ struct x8664_pda { struct task_struct *pcurrent; /* 0 Current process */ - unsigned long data_offset; /* 8 Per cpu data offset from linker - address */ + unsigned long dummy; unsigned long kernelstack; /* 16 top of kernel stack for current */ unsigned long oldrsp; /* 24 user rsp for system call */ int irqcount; /* 32 Irq nesting counter. Starts -1 */ diff --git a/arch/x86/include/asm/percpu.h b/arch/x86/include/asm/percpu.h index 0ed77cf33f7..556f84b9ea9 100644 --- a/arch/x86/include/asm/percpu.h +++ b/arch/x86/include/asm/percpu.h @@ -1,62 +1,13 @@ #ifndef _ASM_X86_PERCPU_H #define _ASM_X86_PERCPU_H -#ifndef __ASSEMBLY__ #ifdef CONFIG_X86_64 -extern void load_pda_offset(int cpu); +#define __percpu_seg gs +#define __percpu_mov_op movq #else -static inline void load_pda_offset(int cpu) { } -#endif -#endif - -#ifdef CONFIG_X86_64 -#include <linux/compiler.h> - -/* Same as asm-generic/percpu.h, except that we store the per cpu offset - in the PDA. Longer term the PDA and every per cpu variable - should be just put into a single section and referenced directly - from %gs */ - -#ifdef CONFIG_SMP -#include <asm/pda.h> - -#define __per_cpu_offset(cpu) (cpu_pda(cpu)->data_offset) -#define __my_cpu_offset read_pda(data_offset) - -#define per_cpu_offset(x) (__per_cpu_offset(x)) - +#define __percpu_seg fs +#define __percpu_mov_op movl #endif -#include <asm-generic/percpu.h> - -DECLARE_PER_CPU(struct x8664_pda, pda); - -/* - * These are supposed to be implemented as a single instruction which - * operates on the per-cpu data base segment. x86-64 doesn't have - * that yet, so this is a fairly inefficient workaround for the - * meantime. The single instruction is atomic with respect to - * preemption and interrupts, so we need to explicitly disable - * interrupts here to achieve the same effect. However, because it - * can be used from within interrupt-disable/enable, we can't actually - * disable interrupts; disabling preemption is enough. - */ -#define x86_read_percpu(var) \ - ({ \ - typeof(per_cpu_var(var)) __tmp; \ - preempt_disable(); \ - __tmp = __get_cpu_var(var); \ - preempt_enable(); \ - __tmp; \ - }) - -#define x86_write_percpu(var, val) \ - do { \ - preempt_disable(); \ - __get_cpu_var(var) = (val); \ - preempt_enable(); \ - } while(0) - -#else /* CONFIG_X86_64 */ #ifdef __ASSEMBLY__ @@ -73,42 +24,26 @@ DECLARE_PER_CPU(struct x8664_pda, pda); * PER_CPU(cpu_gdt_descr, %ebx) */ #ifdef CONFIG_SMP -#define PER_CPU(var, reg) \ - movl %fs:per_cpu__##this_cpu_off, reg; \ +#define PER_CPU(var, reg) \ + __percpu_mov_op %__percpu_seg:per_cpu__this_cpu_off, reg; \ lea per_cpu__##var(reg), reg -#define PER_CPU_VAR(var) %fs:per_cpu__##var +#define PER_CPU_VAR(var) %__percpu_seg:per_cpu__##var #else /* ! SMP */ -#define PER_CPU(var, reg) \ - movl $per_cpu__##var, reg +#define PER_CPU(var, reg) \ + __percpu_mov_op $per_cpu__##var, reg #define PER_CPU_VAR(var) per_cpu__##var #endif /* SMP */ #else /* ...!ASSEMBLY */ -/* - * PER_CPU finds an address of a per-cpu variable. - * - * Args: - * var - variable name - * cpu - 32bit register containing the current CPU number - * - * The resulting address is stored in the "cpu" argument. - * - * Example: - * PER_CPU(cpu_gdt_descr, %ebx) - */ -#ifdef CONFIG_SMP - -#define __my_cpu_offset x86_read_percpu(this_cpu_off) - -/* fs segment starts at (positive) offset == __per_cpu_offset[cpu] */ -#define __percpu_seg "%%fs:" +#include <linux/stringify.h> -#else /* !SMP */ - -#define __percpu_seg "" - -#endif /* SMP */ +#ifdef CONFIG_SMP +#define __percpu_seg_str "%%"__stringify(__percpu_seg)":" +#define __my_cpu_offset x86_read_percpu(this_cpu_off) +#else +#define __percpu_seg_str +#endif #include <asm-generic/percpu.h> @@ -128,20 +63,25 @@ do { \ } \ switch (sizeof(var)) { \ case 1: \ - asm(op "b %1,"__percpu_seg"%0" \ + asm(op "b %1,"__percpu_seg_str"%0" \ : "+m" (var) \ : "ri" ((T__)val)); \ break; \ case 2: \ - asm(op "w %1,"__percpu_seg"%0" \ + asm(op "w %1,"__percpu_seg_str"%0" \ : "+m" (var) \ : "ri" ((T__)val)); \ break; \ case 4: \ - asm(op "l %1,"__percpu_seg"%0" \ + asm(op "l %1,"__percpu_seg_str"%0" \ : "+m" (var) \ : "ri" ((T__)val)); \ break; \ + case 8: \ + asm(op "q %1,"__percpu_seg_str"%0" \ + : "+m" (var) \ + : "r" ((T__)val)); \ + break; \ default: __bad_percpu_size(); \ } \ } while (0) @@ -151,17 +91,22 @@ do { \ typeof(var) ret__; \ switch (sizeof(var)) { \ case 1: \ - asm(op "b "__percpu_seg"%1,%0" \ + asm(op "b "__percpu_seg_str"%1,%0" \ : "=r" (ret__) \ : "m" (var)); \ break; \ case 2: \ - asm(op "w "__percpu_seg"%1,%0" \ + asm(op "w "__percpu_seg_str"%1,%0" \ : "=r" (ret__) \ : "m" (var)); \ break; \ case 4: \ - asm(op "l "__percpu_seg"%1,%0" \ + asm(op "l "__percpu_seg_str"%1,%0" \ + : "=r" (ret__) \ + : "m" (var)); \ + break; \ + case 8: \ + asm(op "q "__percpu_seg_str"%1,%0" \ : "=r" (ret__) \ : "m" (var)); \ break; \ @@ -175,8 +120,14 @@ do { \ #define x86_add_percpu(var, val) percpu_to_op("add", per_cpu__##var, val) #define x86_sub_percpu(var, val) percpu_to_op("sub", per_cpu__##var, val) #define x86_or_percpu(var, val) percpu_to_op("or", per_cpu__##var, val) + +#ifdef CONFIG_X86_64 +extern void load_pda_offset(int cpu); +#else +static inline void load_pda_offset(int cpu) { } +#endif + #endif /* !__ASSEMBLY__ */ -#endif /* !CONFIG_X86_64 */ #ifdef CONFIG_SMP |