From 9ca36101a8d74704d78f10910f89d62de96f9dc8 Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Thu, 7 Dec 2006 02:14:02 +0100 Subject: [PATCH] i386: Basic definitions for i386-pda This patch has the basic definitions of struct i386_pda, and the segment selector in the GDT. asm-i386/pda.h is more or less a direct copy of asm-x86_64/pda.h. The most interesting difference is the use of _proxy_pda, which is used to give gcc a model for the actual memory operations on the real pda structure. No actual reference is ever made to _proxy_pda, so it is never defined. Signed-off-by: Jeremy Fitzhardinge Signed-off-by: Andi Kleen Cc: Chuck Ebbert <76306.1226@compuserve.com> Cc: Zachary Amsden Cc: Jan Beulich Cc: Andi Kleen Signed-off-by: Andrew Morton --- include/asm-i386/pda.h | 95 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 95 insertions(+) create mode 100644 include/asm-i386/pda.h (limited to 'include/asm-i386/pda.h') diff --git a/include/asm-i386/pda.h b/include/asm-i386/pda.h new file mode 100644 index 000000000000..4c39ccb1305c --- /dev/null +++ b/include/asm-i386/pda.h @@ -0,0 +1,95 @@ +/* + Per-processor Data Areas + Jeremy Fitzhardinge 2006 + Based on asm-x86_64/pda.h by Andi Kleen. + */ +#ifndef _I386_PDA_H +#define _I386_PDA_H + +#include + +struct i386_pda +{ + struct i386_pda *_pda; /* pointer to self */ +}; + +extern struct i386_pda *_cpu_pda[]; + +#define cpu_pda(i) (_cpu_pda[i]) + +#define pda_offset(field) offsetof(struct i386_pda, field) + +extern void __bad_pda_field(void); + +/* This variable is never instantiated. It is only used as a stand-in + for the real per-cpu PDA memory, so that gcc can understand what + memory operations the inline asms() below are performing. This + eliminates the need to make the asms volatile or have memory + clobbers, so gcc can readily analyse them. */ +extern struct i386_pda _proxy_pda; + +#define pda_to_op(op,field,val) \ + do { \ + typedef typeof(_proxy_pda.field) T__; \ + if (0) { T__ tmp__; tmp__ = (val); } \ + switch (sizeof(_proxy_pda.field)) { \ + case 1: \ + asm(op "b %1,%%gs:%c2" \ + : "+m" (_proxy_pda.field) \ + :"ri" ((T__)val), \ + "i"(pda_offset(field))); \ + break; \ + case 2: \ + asm(op "w %1,%%gs:%c2" \ + : "+m" (_proxy_pda.field) \ + :"ri" ((T__)val), \ + "i"(pda_offset(field))); \ + break; \ + case 4: \ + asm(op "l %1,%%gs:%c2" \ + : "+m" (_proxy_pda.field) \ + :"ri" ((T__)val), \ + "i"(pda_offset(field))); \ + break; \ + default: __bad_pda_field(); \ + } \ + } while (0) + +#define pda_from_op(op,field) \ + ({ \ + typeof(_proxy_pda.field) ret__; \ + switch (sizeof(_proxy_pda.field)) { \ + case 1: \ + asm(op "b %%gs:%c1,%0" \ + : "=r" (ret__) \ + : "i" (pda_offset(field)), \ + "m" (_proxy_pda.field)); \ + break; \ + case 2: \ + asm(op "w %%gs:%c1,%0" \ + : "=r" (ret__) \ + : "i" (pda_offset(field)), \ + "m" (_proxy_pda.field)); \ + break; \ + case 4: \ + asm(op "l %%gs:%c1,%0" \ + : "=r" (ret__) \ + : "i" (pda_offset(field)), \ + "m" (_proxy_pda.field)); \ + break; \ + default: __bad_pda_field(); \ + } \ + ret__; }) + +/* Return a pointer to a pda field */ +#define pda_addr(field) \ + ((typeof(_proxy_pda.field) *)((unsigned char *)read_pda(_pda) + \ + pda_offset(field))) + +#define read_pda(field) pda_from_op("mov",field) +#define write_pda(field,val) pda_to_op("mov",field,val) +#define add_pda(field,val) pda_to_op("add",field,val) +#define sub_pda(field,val) pda_to_op("sub",field,val) +#define or_pda(field,val) pda_to_op("or",field,val) + +#endif /* _I386_PDA_H */ -- cgit v1.2.3 From b2938f880890ebfcccad356275e0000193153623 Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Thu, 7 Dec 2006 02:14:03 +0100 Subject: [PATCH] i386: Implement smp_processor_id() with the PDA Use the cpu_number in the PDA to implement raw_smp_processor_id. This is a little simpler than using thread_info, though the cpu field in thread_info cannot be removed since it is used for things other than getting the current CPU in common code. Signed-off-by: Jeremy Fitzhardinge Signed-off-by: Andi Kleen Cc: Chuck Ebbert <76306.1226@compuserve.com> Cc: Zachary Amsden Cc: Jan Beulich Cc: Andi Kleen Signed-off-by: Andrew Morton --- arch/i386/kernel/asm-offsets.c | 4 +++- arch/i386/kernel/cpu/common.c | 2 ++ arch/i386/kernel/entry.S | 3 +-- include/asm-i386/pda.h | 2 ++ include/asm-i386/smp.h | 3 ++- 5 files changed, 10 insertions(+), 4 deletions(-) (limited to 'include/asm-i386/pda.h') diff --git a/arch/i386/kernel/asm-offsets.c b/arch/i386/kernel/asm-offsets.c index 9620872d3534..85f1b038e9c3 100644 --- a/arch/i386/kernel/asm-offsets.c +++ b/arch/i386/kernel/asm-offsets.c @@ -51,7 +51,6 @@ void foo(void) OFFSET(TI_exec_domain, thread_info, exec_domain); OFFSET(TI_flags, thread_info, flags); OFFSET(TI_status, thread_info, status); - OFFSET(TI_cpu, thread_info, cpu); OFFSET(TI_preempt_count, thread_info, preempt_count); OFFSET(TI_addr_limit, thread_info, addr_limit); OFFSET(TI_restart_block, thread_info, restart_block); @@ -97,4 +96,7 @@ void foo(void) DEFINE(VDSO_PRELINK, VDSO_PRELINK); OFFSET(crypto_tfm_ctx_offset, crypto_tfm, __crt_ctx); + + BLANK(); + OFFSET(PDA_cpu, i386_pda, cpu_number); } diff --git a/arch/i386/kernel/cpu/common.c b/arch/i386/kernel/cpu/common.c index 4e63d8ce602b..e476202b887f 100644 --- a/arch/i386/kernel/cpu/common.c +++ b/arch/i386/kernel/cpu/common.c @@ -650,6 +650,7 @@ __cpuinit int alloc_gdt(int cpu) /* Initial PDA used by boot CPU */ struct i386_pda boot_pda = { ._pda = &boot_pda, + .cpu_number = 0, }; static inline void set_kernel_gs(void) @@ -694,6 +695,7 @@ __cpuinit int init_gdt(int cpu, struct task_struct *idle) memset(pda, 0, sizeof(*pda)); pda->_pda = pda; + pda->cpu_number = cpu; return 1; } diff --git a/arch/i386/kernel/entry.S b/arch/i386/kernel/entry.S index b99d4a160078..d7423efaeea4 100644 --- a/arch/i386/kernel/entry.S +++ b/arch/i386/kernel/entry.S @@ -524,8 +524,7 @@ syscall_badsys: #define FIXUP_ESPFIX_STACK \ /* since we are on a wrong stack, we cant make it a C code :( */ \ - GET_THREAD_INFO(%ebp); \ - movl TI_cpu(%ebp), %ebx; \ + movl %gs:PDA_cpu, %ebx; \ PER_CPU(cpu_gdt_descr, %ebx); \ movl GDS_address(%ebx), %ebx; \ GET_DESC_BASE(GDT_ENTRY_ESPFIX_SS, %ebx, %eax, %ax, %al, %ah); \ diff --git a/include/asm-i386/pda.h b/include/asm-i386/pda.h index 4c39ccb1305c..f90fde22566d 100644 --- a/include/asm-i386/pda.h +++ b/include/asm-i386/pda.h @@ -11,6 +11,8 @@ struct i386_pda { struct i386_pda *_pda; /* pointer to self */ + + int cpu_number; }; extern struct i386_pda *_cpu_pda[]; diff --git a/include/asm-i386/smp.h b/include/asm-i386/smp.h index bd59c1508e71..64fe624c02ca 100644 --- a/include/asm-i386/smp.h +++ b/include/asm-i386/smp.h @@ -8,6 +8,7 @@ #include #include #include +#include #endif #ifdef CONFIG_X86_LOCAL_APIC @@ -56,7 +57,7 @@ extern void cpu_uninit(void); * from the initial startup. We map APIC_BASE very early in page_setup(), * so this is correct in the x86 case. */ -#define raw_smp_processor_id() (current_thread_info()->cpu) +#define raw_smp_processor_id() (read_pda(cpu_number)) extern cpumask_t cpu_callout_map; extern cpumask_t cpu_callin_map; -- cgit v1.2.3 From ec7fcaabbfb3c5bd5189f857b6ac7bb9745ef291 Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Thu, 7 Dec 2006 02:14:03 +0100 Subject: [PATCH] i386: Implement "current" with the PDA Use the pcurrent field in the PDA to implement the "current" macro. This ends up compiling down to a single instruction to get the current task. Signed-off-by: Jeremy Fitzhardinge Signed-off-by: Andi Kleen Cc: Chuck Ebbert <76306.1226@compuserve.com> Cc: Zachary Amsden Cc: Jan Beulich Cc: Andi Kleen Signed-off-by: Andrew Morton --- arch/i386/kernel/asm-offsets.c | 2 ++ arch/i386/kernel/cpu/common.c | 2 ++ arch/i386/kernel/process.c | 1 + include/asm-i386/current.h | 7 ++++--- include/asm-i386/pda.h | 2 ++ 5 files changed, 11 insertions(+), 3 deletions(-) (limited to 'include/asm-i386/pda.h') diff --git a/arch/i386/kernel/asm-offsets.c b/arch/i386/kernel/asm-offsets.c index 85f1b038e9c3..0666eb0ed7bc 100644 --- a/arch/i386/kernel/asm-offsets.c +++ b/arch/i386/kernel/asm-offsets.c @@ -15,6 +15,7 @@ #include #include #include +#include #define DEFINE(sym, val) \ asm volatile("\n->" #sym " %0 " #val : : "i" (val)) @@ -99,4 +100,5 @@ void foo(void) BLANK(); OFFSET(PDA_cpu, i386_pda, cpu_number); + OFFSET(PDA_pcurrent, i386_pda, pcurrent); } diff --git a/arch/i386/kernel/cpu/common.c b/arch/i386/kernel/cpu/common.c index e476202b887f..6958ae5e2fa5 100644 --- a/arch/i386/kernel/cpu/common.c +++ b/arch/i386/kernel/cpu/common.c @@ -651,6 +651,7 @@ __cpuinit int alloc_gdt(int cpu) struct i386_pda boot_pda = { ._pda = &boot_pda, .cpu_number = 0, + .pcurrent = &init_task, }; static inline void set_kernel_gs(void) @@ -696,6 +697,7 @@ __cpuinit int init_gdt(int cpu, struct task_struct *idle) memset(pda, 0, sizeof(*pda)); pda->_pda = pda; pda->cpu_number = cpu; + pda->pcurrent = idle; return 1; } diff --git a/arch/i386/kernel/process.c b/arch/i386/kernel/process.c index dc4272545179..8749b10d3805 100644 --- a/arch/i386/kernel/process.c +++ b/arch/i386/kernel/process.c @@ -684,6 +684,7 @@ struct task_struct fastcall * __switch_to(struct task_struct *prev_p, struct tas if (unlikely(prev->fs | next->fs)) loadsegment(fs, next->fs); + write_pda(pcurrent, next_p); /* * Restore IOPL if needed. diff --git a/include/asm-i386/current.h b/include/asm-i386/current.h index 3cbbecd79016..5252ee0f6d7a 100644 --- a/include/asm-i386/current.h +++ b/include/asm-i386/current.h @@ -1,13 +1,14 @@ #ifndef _I386_CURRENT_H #define _I386_CURRENT_H -#include +#include +#include struct task_struct; -static __always_inline struct task_struct * get_current(void) +static __always_inline struct task_struct *get_current(void) { - return current_thread_info()->task; + return read_pda(pcurrent); } #define current get_current() diff --git a/include/asm-i386/pda.h b/include/asm-i386/pda.h index f90fde22566d..08a35c478af2 100644 --- a/include/asm-i386/pda.h +++ b/include/asm-i386/pda.h @@ -7,12 +7,14 @@ #define _I386_PDA_H #include +#include struct i386_pda { struct i386_pda *_pda; /* pointer to self */ int cpu_number; + struct task_struct *pcurrent; /* current process */ }; extern struct i386_pda *_cpu_pda[]; -- cgit v1.2.3 From 70463daca852db396ce17f179d2404b257ba0f66 Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Thu, 7 Dec 2006 02:14:03 +0100 Subject: [PATCH] i386: Store the interrupt regs pointer in the PDA Signed-off-by: Jeremy Fitzhardinge Signed-off-by: Andrew Morton Signed-off-by: Andi Kleen --- include/asm-i386/irq_regs.h | 28 +++++++++++++++++++++++++++- include/asm-i386/pda.h | 1 + 2 files changed, 28 insertions(+), 1 deletion(-) (limited to 'include/asm-i386/pda.h') diff --git a/include/asm-i386/irq_regs.h b/include/asm-i386/irq_regs.h index 3dd9c0b70270..a1b3f7f594a2 100644 --- a/include/asm-i386/irq_regs.h +++ b/include/asm-i386/irq_regs.h @@ -1 +1,27 @@ -#include +/* + * Per-cpu current frame pointer - the location of the last exception frame on + * the stack, stored in the PDA. + * + * Jeremy Fitzhardinge + */ +#ifndef _ASM_I386_IRQ_REGS_H +#define _ASM_I386_IRQ_REGS_H + +#include + +static inline struct pt_regs *get_irq_regs(void) +{ + return read_pda(irq_regs); +} + +static inline struct pt_regs *set_irq_regs(struct pt_regs *new_regs) +{ + struct pt_regs *old_regs; + + old_regs = read_pda(irq_regs); + write_pda(irq_regs, new_regs); + + return old_regs; +} + +#endif /* _ASM_I386_IRQ_REGS_H */ diff --git a/include/asm-i386/pda.h b/include/asm-i386/pda.h index 08a35c478af2..2ba2736aa109 100644 --- a/include/asm-i386/pda.h +++ b/include/asm-i386/pda.h @@ -15,6 +15,7 @@ struct i386_pda int cpu_number; struct task_struct *pcurrent; /* current process */ + struct pt_regs *irq_regs; }; extern struct i386_pda *_cpu_pda[]; -- cgit v1.2.3