--- linux-2.6.18-rc2-mm1/include/asm-i386/desc.h 2006-07-29 17:34:57.000000000 +0400 +++ linux-2.6.18-rc2-mm1/include/asm-i386/desc.h 2006-07-29 17:35:07.000000000 +0400 @@ -4,8 +4,6 @@ #include #include -#define CPU_16BIT_STACK_SIZE 1024 - #ifndef __ASSEMBLY__ #include @@ -16,8 +14,6 @@ extern struct desc_struct cpu_gdt_table[GDT_ENTRIES]; -DECLARE_PER_CPU(unsigned char, cpu_16bit_stack[CPU_16BIT_STACK_SIZE]); - struct Xgt_desc_struct { unsigned short size; unsigned long address __attribute__((packed)); --- linux-2.6.18-rc2-mm1/arch/i386/kernel/head.S 2006-07-29 15:32:14.000000000 +0400 +++ linux-2.6.18-rc2-mm1/arch/i386/kernel/head.S 2006-07-29 17:17:51.000000000 +0400 @@ -590,7 +590,7 @@ .quad 0x00009a000000ffff /* 0xc0 APM CS 16 code (16 bit) */ .quad 0x004092000000ffff /* 0xc8 APM DS data */ - .quad 0x0000920000000000 /* 0xd0 - ESPFIX 16-bit SS */ + .quad 0x00cf92000000ffff /* 0xd0 - ESPFIX SS */ .quad 0x0000000000000000 /* 0xd8 - unused */ .quad 0x0000000000000000 /* 0xe0 - unused */ .quad 0x0000000000000000 /* 0xe8 - unused */ --- linux-2.6.18-rc2-mm1/arch/i386/kernel/traps.c 2006-07-29 15:32:14.000000000 +0400 +++ linux-2.6.18-rc2-mm1/arch/i386/kernel/traps.c 2006-07-30 02:19:59.000000000 +0400 @@ -1018,49 +1018,30 @@ #endif } -fastcall void setup_x86_bogus_stack(unsigned char * stk) +fastcall unsigned long patch_espfix_gdt(struct pt_regs *regs, + unsigned long kesp) { - unsigned long *switch16_ptr, *switch32_ptr; - struct pt_regs *regs; - unsigned long stack_top, stack_bot; - unsigned short iret_frame16_off; int cpu = smp_processor_id(); - /* reserve the space on 32bit stack for the magic switch16 pointer */ - memmove(stk, stk + 8, sizeof(struct pt_regs)); - switch16_ptr = (unsigned long *)(stk + sizeof(struct pt_regs)); - regs = (struct pt_regs *)stk; - /* now the switch32 on 16bit stack */ - stack_bot = (unsigned long)&per_cpu(cpu_16bit_stack, cpu); - stack_top = stack_bot + CPU_16BIT_STACK_SIZE; - switch32_ptr = (unsigned long *)(stack_top - 8); - iret_frame16_off = CPU_16BIT_STACK_SIZE - 8 - 20; - /* copy iret frame on 16bit stack */ - memcpy((void *)(stack_bot + iret_frame16_off), ®s->eip, 20); - /* fill in the switch pointers */ - switch16_ptr[0] = (regs->esp & 0xffff0000) | iret_frame16_off; - switch16_ptr[1] = __ESPFIX_SS; - switch32_ptr[0] = (unsigned long)stk + sizeof(struct pt_regs) + - 8 - CPU_16BIT_STACK_SIZE; - switch32_ptr[1] = __KERNEL_DS; -} - -fastcall unsigned char * fixup_x86_bogus_stack(unsigned short sp) -{ - unsigned long *switch32_ptr; - unsigned char *stack16, *stack32; - unsigned long stack_top, stack_bot; - int len; - int cpu = smp_processor_id(); - stack_bot = (unsigned long)&per_cpu(cpu_16bit_stack, cpu); - stack_top = stack_bot + CPU_16BIT_STACK_SIZE; - switch32_ptr = (unsigned long *)(stack_top - 8); - /* copy the data from 16bit stack to 32bit stack */ - len = CPU_16BIT_STACK_SIZE - 8 - sp; - stack16 = (unsigned char *)(stack_bot + sp); - stack32 = (unsigned char *) - (switch32_ptr[0] + CPU_16BIT_STACK_SIZE - 8 - len); - memcpy(stack32, stack16, len); - return stack32; + struct Xgt_desc_struct *cpu_gdt_descr = &per_cpu(cpu_gdt_descr, cpu); + struct desc_struct *gdt = (struct desc_struct *)cpu_gdt_descr->address; + unsigned long base = (kesp - regs->esp) & -THREAD_SIZE; + __u64 desc = *(__u64 *)&gdt[GDT_ENTRY_ESPFIX_SS]; + /* Set up base for espfix segment */ + desc &= 0x00ffff000000ffffULL; + desc |= ((((__u64)base) << 16) & 0x000000ffffff0000ULL) | + ((((__u64)base) << 32) & 0xff00000000000000ULL); + *(__u64 *)&gdt[GDT_ENTRY_ESPFIX_SS] = desc; + return kesp - base; +} + +fastcall unsigned long get_orig_kesp(unsigned long kesp, unsigned long cpu) +{ + /* Since we are on a wrong stack, the smp_processor_id() cannot + * be used. So the cpu number is passed from an assembly. */ + struct Xgt_desc_struct *cpu_gdt_descr = &per_cpu(cpu_gdt_descr, cpu); + struct desc_struct *gdt = (struct desc_struct *)cpu_gdt_descr->address; + unsigned long base = get_desc_base(&gdt[GDT_ENTRY_ESPFIX_SS].a); + return base + kesp; } /* --- linux-2.6.18-rc2-mm1/arch/i386/kernel/entry.S 2006-07-29 15:29:00.000000000 +0400 +++ linux-2.6.18-rc2-mm1/arch/i386/kernel/entry.S 2006-07-30 02:19:47.000000000 +0400 @@ -380,8 +380,6 @@ 1: iret .section .fixup,"ax" iret_exc: - TRACE_IRQS_ON - sti pushl $0 # no error code pushl $do_iret_error jmp error_code @@ -403,23 +401,18 @@ * This is an "official" bug of all the x86-compatible * CPUs, which we can try to work around to make * dosemu and wine happy. */ - subl $8, %esp # reserve space for switch16 pointer - CFI_ADJUST_CFA_OFFSET 8 + movl %esp, %eax # pt_regs pointer + movl %esp, %edx + call patch_espfix_gdt + pushl $__ESPFIX_SS + CFI_ADJUST_CFA_OFFSET 4 + pushl %eax + CFI_ADJUST_CFA_OFFSET 4 cli TRACE_IRQS_OFF - movl %esp, %eax - /* Set up the 16bit stack frame with switch32 pointer on top, - * and a switch16 pointer on top of the current frame. */ - call setup_x86_bogus_stack - CFI_ADJUST_CFA_OFFSET -8 # frame has moved - TRACE_IRQS_IRET - RESTORE_REGS - lss 20+4(%esp), %esp # switch to 16bit stack -1: iret -.section __ex_table,"a" - .align 4 - .long 1b,iret_exc -.previous + lss (%esp), %esp + CFI_ADJUST_CFA_OFFSET -8 + jmp restore_nocheck CFI_ENDPROC # perform work that needs to be done immediately before resumption @@ -510,26 +503,23 @@ #define FIXUP_ESPFIX_STACK \ movl %esp, %eax; \ - /* switch to 32bit stack using the pointer on top of 16bit stack */ \ - lss %ss:CPU_16BIT_STACK_SIZE-8, %esp; \ - /* copy data from 16bit stack to 32bit stack */ \ - call fixup_x86_bogus_stack; \ - /* put ESP to the proper location */ \ - movl %eax, %esp; -#define UNWIND_ESPFIX_STACK \ + GET_THREAD_INFO(%ebp); \ + movl TI_cpu(%ebp), %edx; \ + call get_orig_kesp; \ + pushl $__KERNEL_DS; \ pushl %eax; \ - CFI_ADJUST_CFA_OFFSET 4; \ + lss (%esp), %esp; +#define UNWIND_ESPFIX_STACK \ movl %ss, %eax; \ - /* see if on 16bit stack */ \ + /* see if on espfix stack */ \ cmpw $__ESPFIX_SS, %ax; \ je 28f; \ -27: popl %eax; \ - CFI_ADJUST_CFA_OFFSET -4; \ +27:; \ .section .fixup,"ax"; \ 28: movl $__KERNEL_DS, %eax; \ movl %eax, %ds; \ movl %eax, %es; \ - /* switch to 32bit stack */ \ + /* switch to normal stack */ \ FIXUP_ESPFIX_STACK; \ jmp 27b; \ .previous @@ -600,8 +590,6 @@ /*CFI_REL_OFFSET ds, 0*/ pushl %eax CFI_ADJUST_CFA_OFFSET 4 - CFI_REL_OFFSET eax, 0 - xorl %eax, %eax pushl %ebp CFI_ADJUST_CFA_OFFSET 4 CFI_REL_OFFSET ebp, 0 @@ -614,7 +602,6 @@ pushl %edx CFI_ADJUST_CFA_OFFSET 4 CFI_REL_OFFSET edx, 0 - decl %eax # eax = -1 pushl %ecx CFI_ADJUST_CFA_OFFSET 4 CFI_REL_OFFSET ecx, 0 @@ -631,7 +618,7 @@ /*CFI_REGISTER es, ecx*/ movl ES(%esp), %edi # get the function address movl ORIG_EAX(%esp), %edx # get the error code - movl %eax, ORIG_EAX(%esp) + movl $-1, ORIG_EAX(%esp) movl %ecx, ES(%esp) /*CFI_REL_OFFSET es, ES*/ movl $(__USER_DS), %ecx @@ -733,7 +720,7 @@ cmpw $__ESPFIX_SS, %ax popl %eax CFI_ADJUST_CFA_OFFSET -4 - je nmi_16bit_stack + je nmi_espfix_stack cmpl $sysenter_entry,(%esp) je nmi_stack_fixup pushl %eax @@ -772,14 +759,13 @@ FIX_STACK(24,nmi_stack_correct, 1) jmp nmi_stack_correct -nmi_16bit_stack: +nmi_espfix_stack: RING0_INT_FRAME /* create the pointer to lss back */ pushl %ss CFI_ADJUST_CFA_OFFSET 4 pushl %esp CFI_ADJUST_CFA_OFFSET 4 - movzwl %sp, %esp addw $4, (%esp) /* copy the iret frame of 12 bytes */ .rept 3 @@ -790,11 +776,11 @@ CFI_ADJUST_CFA_OFFSET 4 SAVE_ALL FIXUP_ESPFIX_STACK # %eax == %esp - CFI_ADJUST_CFA_OFFSET -20 # the frame has now moved + CFI_ADJUST_CFA_OFFSET -20 xorl %edx,%edx # zero error code call do_nmi RESTORE_REGS - lss 12+4(%esp), %esp # back to 16bit stack + lss 12+4(%esp), %esp # back to espfix stack 1: iret CFI_ENDPROC .section __ex_table,"a" --- linux-2.6.18-rc2-mm1/arch/i386/kernel/cpu/common.c 2006-07-29 15:29:00.000000000 +0400 +++ linux-2.6.18-rc2-mm1/arch/i386/kernel/cpu/common.c 2006-07-29 17:39:01.000000000 +0400 @@ -24,9 +24,6 @@ DEFINE_PER_CPU(struct Xgt_desc_struct, cpu_gdt_descr); EXPORT_PER_CPU_SYMBOL(cpu_gdt_descr); -DEFINE_PER_CPU(unsigned char, cpu_16bit_stack[CPU_16BIT_STACK_SIZE]); -EXPORT_PER_CPU_SYMBOL(cpu_16bit_stack); - static int cachesize_override __cpuinitdata = -1; static int disable_x86_fxsr __cpuinitdata; static int disable_x86_serial_nr __cpuinitdata = 1; @@ -594,7 +591,6 @@ struct tss_struct * t = &per_cpu(init_tss, cpu); struct thread_struct *thread = ¤t->thread; struct desc_struct *gdt; - __u32 stk16_off = (__u32)&per_cpu(cpu_16bit_stack, cpu); struct Xgt_desc_struct *cpu_gdt_descr = &per_cpu(cpu_gdt_descr, cpu); if (cpu_test_and_set(cpu, cpu_initialized)) { @@ -642,13 +638,6 @@ * and set up the GDT descriptor: */ memcpy(gdt, cpu_gdt_table, GDT_SIZE); - - /* Set up GDT entry for 16bit stack */ - *(__u64 *)(&gdt[GDT_ENTRY_ESPFIX_SS]) |= - ((((__u64)stk16_off) << 16) & 0x000000ffffff0000ULL) | - ((((__u64)stk16_off) << 32) & 0xff00000000000000ULL) | - (CPU_16BIT_STACK_SIZE - 1); - cpu_gdt_descr->size = GDT_SIZE - 1; cpu_gdt_descr->address = (unsigned long)gdt;