--- zzzz-none-000/linux-3.10.107/arch/x86/kernel/process_64.c 2017-06-27 09:49:32.000000000 +0000 +++ scorpion-7490-727/linux-3.10.107/arch/x86/kernel/process_64.c 2021-02-04 17:41:59.000000000 +0000 @@ -38,8 +38,7 @@ #include #include -#include -#include +#include #include #include #include @@ -53,7 +52,7 @@ asmlinkage extern void ret_from_fork(void); -DEFINE_PER_CPU(unsigned long, old_rsp); +__visible DEFINE_PER_CPU(unsigned long, rsp_scratch); /* Prints also some state that isn't saved in the pt_regs */ void __show_regs(struct pt_regs *regs, int all) @@ -64,7 +63,7 @@ unsigned int ds, cs, es; printk(KERN_DEFAULT "RIP: %04lx:[<%016lx>] ", regs->cs & 0xffff, regs->ip); - printk_address(regs->ip, 1); + printk_address(regs->ip); printk(KERN_DEFAULT "RSP: %04lx:%016lx EFLAGS: %08lx\n", regs->ss, regs->sp, regs->flags); printk(KERN_DEFAULT "RAX: %016lx RBX: %016lx RCX: %016lx\n", @@ -94,7 +93,7 @@ cr0 = read_cr0(); cr2 = read_cr2(); cr3 = read_cr3(); - cr4 = read_cr4(); + cr4 = __read_cr4(); printk(KERN_DEFAULT "FS: %016lx(%04x) GS:%016lx(%04x) knlGS:%016lx\n", fs, fsindex, gs, gsindex, shadowgs); @@ -106,23 +105,32 @@ get_debugreg(d0, 0); get_debugreg(d1, 1); get_debugreg(d2, 2); - printk(KERN_DEFAULT "DR0: %016lx DR1: %016lx DR2: %016lx\n", d0, d1, d2); get_debugreg(d3, 3); get_debugreg(d6, 6); get_debugreg(d7, 7); + + /* Only print out debug registers if they are in their non-default state. */ + if ((d0 == 0) && (d1 == 0) && (d2 == 0) && (d3 == 0) && + (d6 == DR6_RESERVED) && (d7 == 0x400)) + return; + + printk(KERN_DEFAULT "DR0: %016lx DR1: %016lx DR2: %016lx\n", d0, d1, d2); printk(KERN_DEFAULT "DR3: %016lx DR6: %016lx DR7: %016lx\n", d3, d6, d7); + } void release_thread(struct task_struct *dead_task) { if (dead_task->mm) { - if (dead_task->mm->context.size) { +#ifdef CONFIG_MODIFY_LDT_SYSCALL + if (dead_task->mm->context.ldt) { pr_warn("WARNING: dead process %s still has LDT? <%p/%d>\n", dead_task->comm, dead_task->mm->context.ldt, - dead_task->mm->context.size); + dead_task->mm->context.ldt->size); BUG(); } +#endif } } @@ -145,8 +153,8 @@ return get_desc_base(&t->thread.tls_array[tls]); } -int copy_thread(unsigned long clone_flags, unsigned long sp, - unsigned long arg, struct task_struct *p) +int copy_thread_tls(unsigned long clone_flags, unsigned long sp, + unsigned long arg, struct task_struct *p, unsigned long tls) { int err; struct pt_regs *childregs; @@ -155,9 +163,7 @@ p->thread.sp0 = (unsigned long)task_stack_page(p) + THREAD_SIZE; childregs = task_pt_regs(p); p->thread.sp = (unsigned long) childregs; - p->thread.usersp = me->thread.usersp; set_tsk_thread_flag(p, TIF_FORK); - p->fpu_counter = 0; p->thread.io_bitmap_ptr = NULL; savesegment(gs, p->thread.gsindex); @@ -187,8 +193,6 @@ childregs->sp = sp; err = -ENOMEM; - memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps)); - if (unlikely(test_tsk_thread_flag(me, TIF_IO_BITMAP))) { p->thread.io_bitmap_ptr = kmemdup(me->thread.io_bitmap_ptr, IO_BITMAP_BYTES, GFP_KERNEL); @@ -204,12 +208,12 @@ */ if (clone_flags & CLONE_SETTLS) { #ifdef CONFIG_IA32_EMULATION - if (test_thread_flag(TIF_IA32)) + if (is_ia32_task()) err = do_set_thread_area(p, -1, - (struct user_desc __user *)childregs->si, 0); + (struct user_desc __user *)tls, 0); else #endif - err = do_arch_prctl(p, ARCH_SET_FS, childregs->r8); + err = do_arch_prctl(p, ARCH_SET_FS, tls); if (err) goto out; } @@ -232,13 +236,12 @@ loadsegment(es, _ds); loadsegment(ds, _ds); load_gs_index(0); - current->thread.usersp = new_sp; regs->ip = new_ip; regs->sp = new_sp; - this_cpu_write(old_rsp, new_sp); regs->cs = _cs; regs->ss = _ss; regs->flags = X86_EFLAGS_IF; + force_iret(); } void @@ -248,8 +251,8 @@ __USER_CS, __USER_DS, 0); } -#ifdef CONFIG_IA32_EMULATION -void start_thread_ia32(struct pt_regs *regs, u32 new_ip, u32 new_sp) +#ifdef CONFIG_COMPAT +void compat_start_thread(struct pt_regs *regs, u32 new_ip, u32 new_sp) { start_thread_common(regs, new_ip, new_sp, test_thread_flag(TIF_X32) @@ -268,20 +271,19 @@ * Kprobes not supported here. Set the probe on schedule instead. * Function graph tracer not supported too. */ -__notrace_funcgraph struct task_struct * +__visible __notrace_funcgraph struct task_struct * __switch_to(struct task_struct *prev_p, struct task_struct *next_p) { struct thread_struct *prev = &prev_p->thread; struct thread_struct *next = &next_p->thread; + struct fpu *prev_fpu = &prev->fpu; + struct fpu *next_fpu = &next->fpu; int cpu = smp_processor_id(); - struct tss_struct *tss = &per_cpu(init_tss, cpu); + struct tss_struct *tss = &per_cpu(cpu_tss, cpu); unsigned fsindex, gsindex; - fpu_switch_t fpu; + fpu_switch_t fpu_switch; - fpu = switch_fpu_prepare(prev_p, next_p, cpu); - - /* Reload esp0 and ss1. */ - load_sp0(tss, next); + fpu_switch = switch_fpu_prepare(prev_fpu, next_fpu, cpu); /* We must save %fs and %gs before load_TLS() because * %fs and %gs may be cleared by load_TLS(). @@ -301,7 +303,7 @@ * Leave lazy mode, flushing any hypercalls made here. This * must be done after loading TLS entries in the GDT but before * loading segments that might reference them, and and it must - * be done before math_state_restore, so the TS bit is up to + * be done before fpu__restore(), so the TS bit is up to * date. */ arch_end_context_switch(next_p); @@ -331,7 +333,7 @@ /* * Switch FS and GS. * - * These are even more complicated than FS and GS: they have + * These are even more complicated than DS and ES: they have * 64-bit bases are that controlled by arch_prctl. Those bases * only differ from the values in the GDT or LDT if the selector * is 0. @@ -393,18 +395,15 @@ wrmsrl(MSR_KERNEL_GS_BASE, next->gs); prev->gsindex = gsindex; - switch_fpu_finish(next_p, fpu); + switch_fpu_finish(next_fpu, fpu_switch); /* * Switch the PDA and FPU contexts. */ - prev->usersp = this_cpu_read(old_rsp); - this_cpu_write(old_rsp, next->usersp); this_cpu_write(current_task, next_p); - this_cpu_write(kernel_stack, - (unsigned long)task_stack_page(next_p) + - THREAD_SIZE - KERNEL_STACK_OFFSET); + /* Reload esp0 and ss1. This changes current_thread_info(). */ + load_sp0(tss, next); /* * Now maybe reload the debug registers and handle I/O bitmaps @@ -419,11 +418,39 @@ * current_pt_regs()->flags may not match the current task's * intended IOPL. We need to switch it manually. */ - if (unlikely(xen_pv_domain() && + if (unlikely(static_cpu_has(X86_FEATURE_XENPV) && prev->iopl != next->iopl)) xen_set_iopl_mask(next->iopl); #endif + if (static_cpu_has_bug(X86_BUG_SYSRET_SS_ATTRS)) { + /* + * AMD CPUs have a misfeature: SYSRET sets the SS selector but + * does not update the cached descriptor. As a result, if we + * do SYSRET while SS is NULL, we'll end up in user mode with + * SS apparently equal to __USER_DS but actually unusable. + * + * The straightforward workaround would be to fix it up just + * before SYSRET, but that would slow down the system call + * fast paths. Instead, we ensure that SS is never NULL in + * system call context. We do this by replacing NULL SS + * selectors at every context switch. SYSCALL sets up a valid + * SS, so the only way to get NULL is to re-enter the kernel + * from CPL 3 through an interrupt. Since that can't happen + * in the same task as a running syscall, we are guaranteed to + * context switch between every interrupt vector entry and a + * subsequent SYSRET. + * + * We read SS first because SS reads are much faster than + * writes. Out of caution, we force SS to __KERNEL_DS even if + * it previously had a different non-NULL value. + */ + unsigned short ss_sel; + savesegment(ss, ss_sel); + if (ss_sel != __KERNEL_DS) + loadsegment(ss, __KERNEL_DS); + } + return prev_p; } @@ -455,12 +482,11 @@ set_thread_flag(TIF_ADDR32); /* Mark the associated mm as containing 32-bit tasks. */ - if (current->mm) - current->mm->context.ia32_compat = 1; - if (x32) { clear_thread_flag(TIF_IA32); set_thread_flag(TIF_X32); + if (current->mm) + current->mm->context.ia32_compat = TIF_X32; current->personality &= ~READ_IMPLIES_EXEC; /* is_compat_task() uses the presence of the x32 syscall bit flag to determine compat status */ @@ -468,6 +494,8 @@ } else { set_thread_flag(TIF_IA32); clear_thread_flag(TIF_X32); + if (current->mm) + current->mm->context.ia32_compat = TIF_IA32; current->personality |= force_personality32; /* Prepare the first "return" to user space */ current_thread_info()->status |= TS_COMPAT; @@ -475,30 +503,6 @@ } EXPORT_SYMBOL_GPL(set_personality_ia32); -unsigned long get_wchan(struct task_struct *p) -{ - unsigned long stack; - u64 fp, ip; - int count = 0; - - if (!p || p == current || p->state == TASK_RUNNING) - return 0; - stack = (unsigned long)task_stack_page(p); - if (p->thread.sp < stack || p->thread.sp >= stack+THREAD_SIZE) - return 0; - fp = *(u64 *)(p->thread.sp); - do { - if (fp < (unsigned long)stack || - fp >= (unsigned long)stack+THREAD_SIZE) - return 0; - ip = *(u64 *)(fp+8); - if (!in_sched_functions(ip)) - return ip; - fp = *(u64 *)fp; - } while (count++ < 16); - return 0; -} - long do_arch_prctl(struct task_struct *task, int code, unsigned long addr) { int ret = 0; @@ -601,6 +605,5 @@ unsigned long KSTK_ESP(struct task_struct *task) { - return (test_tsk_thread_flag(task, TIF_IA32)) ? - (task_pt_regs(task)->sp) : ((task)->thread.usersp); + return task_pt_regs(task)->sp; }