mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-16 00:36:40 +07:00
c1bd55f922
For 32-bit userspace on a 64-bit kernel, this requires modifying stub32_clone to actually swap the appropriate arguments to match CONFIG_CLONE_BACKWARDS, rather than just leaving the C argument for tls broken. Patch co-authored by Josh Triplett and Thiago Macieira. Signed-off-by: Josh Triplett <josh@joshtriplett.org> Acked-by: Andy Lutomirski <luto@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Thiago Macieira <thiago.macieira@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
628 lines
17 KiB
C
628 lines
17 KiB
C
/*
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* Copyright (C) 1995 Linus Torvalds
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*
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* Pentium III FXSR, SSE support
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* Gareth Hughes <gareth@valinux.com>, May 2000
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*
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* X86-64 port
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* Andi Kleen.
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*
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* CPU hotplug support - ashok.raj@intel.com
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*/
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/*
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* This file handles the architecture-dependent parts of process handling..
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*/
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#include <linux/cpu.h>
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#include <linux/errno.h>
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#include <linux/sched.h>
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#include <linux/fs.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/elfcore.h>
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#include <linux/smp.h>
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#include <linux/slab.h>
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#include <linux/user.h>
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#include <linux/interrupt.h>
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#include <linux/delay.h>
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#include <linux/module.h>
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#include <linux/ptrace.h>
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#include <linux/notifier.h>
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#include <linux/kprobes.h>
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#include <linux/kdebug.h>
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#include <linux/prctl.h>
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#include <linux/uaccess.h>
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#include <linux/io.h>
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#include <linux/ftrace.h>
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#include <asm/pgtable.h>
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#include <asm/processor.h>
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#include <asm/fpu/internal.h>
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#include <asm/mmu_context.h>
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#include <asm/prctl.h>
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#include <asm/desc.h>
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#include <asm/proto.h>
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#include <asm/ia32.h>
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#include <asm/idle.h>
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#include <asm/syscalls.h>
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#include <asm/debugreg.h>
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#include <asm/switch_to.h>
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asmlinkage extern void ret_from_fork(void);
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__visible DEFINE_PER_CPU(unsigned long, rsp_scratch);
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/* Prints also some state that isn't saved in the pt_regs */
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void __show_regs(struct pt_regs *regs, int all)
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{
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unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L, fs, gs, shadowgs;
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unsigned long d0, d1, d2, d3, d6, d7;
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unsigned int fsindex, gsindex;
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unsigned int ds, cs, es;
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printk(KERN_DEFAULT "RIP: %04lx:[<%016lx>] ", regs->cs & 0xffff, regs->ip);
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printk_address(regs->ip);
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printk(KERN_DEFAULT "RSP: %04lx:%016lx EFLAGS: %08lx\n", regs->ss,
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regs->sp, regs->flags);
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printk(KERN_DEFAULT "RAX: %016lx RBX: %016lx RCX: %016lx\n",
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regs->ax, regs->bx, regs->cx);
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printk(KERN_DEFAULT "RDX: %016lx RSI: %016lx RDI: %016lx\n",
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regs->dx, regs->si, regs->di);
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printk(KERN_DEFAULT "RBP: %016lx R08: %016lx R09: %016lx\n",
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regs->bp, regs->r8, regs->r9);
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printk(KERN_DEFAULT "R10: %016lx R11: %016lx R12: %016lx\n",
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regs->r10, regs->r11, regs->r12);
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printk(KERN_DEFAULT "R13: %016lx R14: %016lx R15: %016lx\n",
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regs->r13, regs->r14, regs->r15);
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asm("movl %%ds,%0" : "=r" (ds));
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asm("movl %%cs,%0" : "=r" (cs));
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asm("movl %%es,%0" : "=r" (es));
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asm("movl %%fs,%0" : "=r" (fsindex));
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asm("movl %%gs,%0" : "=r" (gsindex));
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rdmsrl(MSR_FS_BASE, fs);
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rdmsrl(MSR_GS_BASE, gs);
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rdmsrl(MSR_KERNEL_GS_BASE, shadowgs);
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if (!all)
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return;
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cr0 = read_cr0();
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cr2 = read_cr2();
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cr3 = read_cr3();
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cr4 = __read_cr4();
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printk(KERN_DEFAULT "FS: %016lx(%04x) GS:%016lx(%04x) knlGS:%016lx\n",
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fs, fsindex, gs, gsindex, shadowgs);
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printk(KERN_DEFAULT "CS: %04x DS: %04x ES: %04x CR0: %016lx\n", cs, ds,
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es, cr0);
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printk(KERN_DEFAULT "CR2: %016lx CR3: %016lx CR4: %016lx\n", cr2, cr3,
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cr4);
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get_debugreg(d0, 0);
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get_debugreg(d1, 1);
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get_debugreg(d2, 2);
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get_debugreg(d3, 3);
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get_debugreg(d6, 6);
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get_debugreg(d7, 7);
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/* Only print out debug registers if they are in their non-default state. */
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if ((d0 == 0) && (d1 == 0) && (d2 == 0) && (d3 == 0) &&
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(d6 == DR6_RESERVED) && (d7 == 0x400))
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return;
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printk(KERN_DEFAULT "DR0: %016lx DR1: %016lx DR2: %016lx\n", d0, d1, d2);
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printk(KERN_DEFAULT "DR3: %016lx DR6: %016lx DR7: %016lx\n", d3, d6, d7);
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}
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void release_thread(struct task_struct *dead_task)
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{
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if (dead_task->mm) {
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if (dead_task->mm->context.size) {
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pr_warn("WARNING: dead process %s still has LDT? <%p/%d>\n",
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dead_task->comm,
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dead_task->mm->context.ldt,
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dead_task->mm->context.size);
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BUG();
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}
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}
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}
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static inline void set_32bit_tls(struct task_struct *t, int tls, u32 addr)
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{
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struct user_desc ud = {
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.base_addr = addr,
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.limit = 0xfffff,
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.seg_32bit = 1,
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.limit_in_pages = 1,
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.useable = 1,
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};
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struct desc_struct *desc = t->thread.tls_array;
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desc += tls;
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fill_ldt(desc, &ud);
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}
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static inline u32 read_32bit_tls(struct task_struct *t, int tls)
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{
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return get_desc_base(&t->thread.tls_array[tls]);
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}
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int copy_thread_tls(unsigned long clone_flags, unsigned long sp,
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unsigned long arg, struct task_struct *p, unsigned long tls)
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{
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int err;
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struct pt_regs *childregs;
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struct task_struct *me = current;
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p->thread.sp0 = (unsigned long)task_stack_page(p) + THREAD_SIZE;
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childregs = task_pt_regs(p);
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p->thread.sp = (unsigned long) childregs;
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set_tsk_thread_flag(p, TIF_FORK);
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p->thread.io_bitmap_ptr = NULL;
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savesegment(gs, p->thread.gsindex);
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p->thread.gs = p->thread.gsindex ? 0 : me->thread.gs;
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savesegment(fs, p->thread.fsindex);
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p->thread.fs = p->thread.fsindex ? 0 : me->thread.fs;
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savesegment(es, p->thread.es);
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savesegment(ds, p->thread.ds);
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memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
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if (unlikely(p->flags & PF_KTHREAD)) {
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/* kernel thread */
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memset(childregs, 0, sizeof(struct pt_regs));
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childregs->sp = (unsigned long)childregs;
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childregs->ss = __KERNEL_DS;
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childregs->bx = sp; /* function */
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childregs->bp = arg;
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childregs->orig_ax = -1;
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childregs->cs = __KERNEL_CS | get_kernel_rpl();
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childregs->flags = X86_EFLAGS_IF | X86_EFLAGS_FIXED;
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return 0;
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}
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*childregs = *current_pt_regs();
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childregs->ax = 0;
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if (sp)
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childregs->sp = sp;
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err = -ENOMEM;
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if (unlikely(test_tsk_thread_flag(me, TIF_IO_BITMAP))) {
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p->thread.io_bitmap_ptr = kmemdup(me->thread.io_bitmap_ptr,
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IO_BITMAP_BYTES, GFP_KERNEL);
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if (!p->thread.io_bitmap_ptr) {
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p->thread.io_bitmap_max = 0;
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return -ENOMEM;
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}
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set_tsk_thread_flag(p, TIF_IO_BITMAP);
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}
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/*
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* Set a new TLS for the child thread?
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*/
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if (clone_flags & CLONE_SETTLS) {
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#ifdef CONFIG_IA32_EMULATION
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if (is_ia32_task())
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err = do_set_thread_area(p, -1,
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(struct user_desc __user *)tls, 0);
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else
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#endif
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err = do_arch_prctl(p, ARCH_SET_FS, tls);
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if (err)
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goto out;
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}
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err = 0;
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out:
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if (err && p->thread.io_bitmap_ptr) {
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kfree(p->thread.io_bitmap_ptr);
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p->thread.io_bitmap_max = 0;
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}
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return err;
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}
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static void
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start_thread_common(struct pt_regs *regs, unsigned long new_ip,
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unsigned long new_sp,
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unsigned int _cs, unsigned int _ss, unsigned int _ds)
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{
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loadsegment(fs, 0);
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loadsegment(es, _ds);
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loadsegment(ds, _ds);
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load_gs_index(0);
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regs->ip = new_ip;
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regs->sp = new_sp;
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regs->cs = _cs;
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regs->ss = _ss;
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regs->flags = X86_EFLAGS_IF;
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force_iret();
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}
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void
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start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp)
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{
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start_thread_common(regs, new_ip, new_sp,
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__USER_CS, __USER_DS, 0);
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}
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#ifdef CONFIG_IA32_EMULATION
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void start_thread_ia32(struct pt_regs *regs, u32 new_ip, u32 new_sp)
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{
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start_thread_common(regs, new_ip, new_sp,
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test_thread_flag(TIF_X32)
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? __USER_CS : __USER32_CS,
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__USER_DS, __USER_DS);
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}
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#endif
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/*
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* switch_to(x,y) should switch tasks from x to y.
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*
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* This could still be optimized:
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* - fold all the options into a flag word and test it with a single test.
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* - could test fs/gs bitsliced
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*
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* Kprobes not supported here. Set the probe on schedule instead.
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* Function graph tracer not supported too.
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*/
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__visible __notrace_funcgraph struct task_struct *
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__switch_to(struct task_struct *prev_p, struct task_struct *next_p)
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{
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struct thread_struct *prev = &prev_p->thread;
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struct thread_struct *next = &next_p->thread;
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struct fpu *prev_fpu = &prev->fpu;
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struct fpu *next_fpu = &next->fpu;
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int cpu = smp_processor_id();
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struct tss_struct *tss = &per_cpu(cpu_tss, cpu);
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unsigned fsindex, gsindex;
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fpu_switch_t fpu_switch;
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fpu_switch = switch_fpu_prepare(prev_fpu, next_fpu, cpu);
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/* We must save %fs and %gs before load_TLS() because
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* %fs and %gs may be cleared by load_TLS().
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*
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* (e.g. xen_load_tls())
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*/
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savesegment(fs, fsindex);
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savesegment(gs, gsindex);
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/*
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* Load TLS before restoring any segments so that segment loads
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* reference the correct GDT entries.
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*/
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load_TLS(next, cpu);
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/*
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* Leave lazy mode, flushing any hypercalls made here. This
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* must be done after loading TLS entries in the GDT but before
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* loading segments that might reference them, and and it must
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* be done before fpu__restore(), so the TS bit is up to
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* date.
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*/
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arch_end_context_switch(next_p);
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/* Switch DS and ES.
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*
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* Reading them only returns the selectors, but writing them (if
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* nonzero) loads the full descriptor from the GDT or LDT. The
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* LDT for next is loaded in switch_mm, and the GDT is loaded
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* above.
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*
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* We therefore need to write new values to the segment
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* registers on every context switch unless both the new and old
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* values are zero.
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*
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* Note that we don't need to do anything for CS and SS, as
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* those are saved and restored as part of pt_regs.
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*/
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savesegment(es, prev->es);
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if (unlikely(next->es | prev->es))
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loadsegment(es, next->es);
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savesegment(ds, prev->ds);
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if (unlikely(next->ds | prev->ds))
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loadsegment(ds, next->ds);
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/*
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* Switch FS and GS.
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*
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* These are even more complicated than FS and GS: they have
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* 64-bit bases are that controlled by arch_prctl. Those bases
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* only differ from the values in the GDT or LDT if the selector
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* is 0.
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*
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* Loading the segment register resets the hidden base part of
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* the register to 0 or the value from the GDT / LDT. If the
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* next base address zero, writing 0 to the segment register is
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* much faster than using wrmsr to explicitly zero the base.
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*
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* The thread_struct.fs and thread_struct.gs values are 0
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* if the fs and gs bases respectively are not overridden
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* from the values implied by fsindex and gsindex. They
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* are nonzero, and store the nonzero base addresses, if
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* the bases are overridden.
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*
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* (fs != 0 && fsindex != 0) || (gs != 0 && gsindex != 0) should
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* be impossible.
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*
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* Therefore we need to reload the segment registers if either
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* the old or new selector is nonzero, and we need to override
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* the base address if next thread expects it to be overridden.
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*
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* This code is unnecessarily slow in the case where the old and
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* new indexes are zero and the new base is nonzero -- it will
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* unnecessarily write 0 to the selector before writing the new
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* base address.
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*
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* Note: This all depends on arch_prctl being the only way that
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* user code can override the segment base. Once wrfsbase and
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* wrgsbase are enabled, most of this code will need to change.
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*/
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if (unlikely(fsindex | next->fsindex | prev->fs)) {
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loadsegment(fs, next->fsindex);
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/*
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* If user code wrote a nonzero value to FS, then it also
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* cleared the overridden base address.
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*
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* XXX: if user code wrote 0 to FS and cleared the base
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* address itself, we won't notice and we'll incorrectly
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* restore the prior base address next time we reschdule
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* the process.
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*/
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if (fsindex)
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prev->fs = 0;
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}
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if (next->fs)
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wrmsrl(MSR_FS_BASE, next->fs);
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prev->fsindex = fsindex;
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if (unlikely(gsindex | next->gsindex | prev->gs)) {
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load_gs_index(next->gsindex);
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/* This works (and fails) the same way as fsindex above. */
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if (gsindex)
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prev->gs = 0;
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}
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if (next->gs)
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wrmsrl(MSR_KERNEL_GS_BASE, next->gs);
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prev->gsindex = gsindex;
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switch_fpu_finish(next_fpu, fpu_switch);
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/*
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* Switch the PDA and FPU contexts.
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*/
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this_cpu_write(current_task, next_p);
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/*
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* If it were not for PREEMPT_ACTIVE we could guarantee that the
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* preempt_count of all tasks was equal here and this would not be
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* needed.
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*/
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task_thread_info(prev_p)->saved_preempt_count = this_cpu_read(__preempt_count);
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this_cpu_write(__preempt_count, task_thread_info(next_p)->saved_preempt_count);
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/* Reload esp0 and ss1. This changes current_thread_info(). */
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load_sp0(tss, next);
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/*
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* Now maybe reload the debug registers and handle I/O bitmaps
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*/
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if (unlikely(task_thread_info(next_p)->flags & _TIF_WORK_CTXSW_NEXT ||
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task_thread_info(prev_p)->flags & _TIF_WORK_CTXSW_PREV))
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__switch_to_xtra(prev_p, next_p, tss);
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if (static_cpu_has_bug(X86_BUG_SYSRET_SS_ATTRS)) {
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/*
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* AMD CPUs have a misfeature: SYSRET sets the SS selector but
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* does not update the cached descriptor. As a result, if we
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* do SYSRET while SS is NULL, we'll end up in user mode with
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* SS apparently equal to __USER_DS but actually unusable.
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*
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* The straightforward workaround would be to fix it up just
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* before SYSRET, but that would slow down the system call
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* fast paths. Instead, we ensure that SS is never NULL in
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* system call context. We do this by replacing NULL SS
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* selectors at every context switch. SYSCALL sets up a valid
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* SS, so the only way to get NULL is to re-enter the kernel
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* from CPL 3 through an interrupt. Since that can't happen
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* in the same task as a running syscall, we are guaranteed to
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* context switch between every interrupt vector entry and a
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* subsequent SYSRET.
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*
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* We read SS first because SS reads are much faster than
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* writes. Out of caution, we force SS to __KERNEL_DS even if
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* it previously had a different non-NULL value.
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*/
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unsigned short ss_sel;
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savesegment(ss, ss_sel);
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if (ss_sel != __KERNEL_DS)
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loadsegment(ss, __KERNEL_DS);
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}
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return prev_p;
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}
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void set_personality_64bit(void)
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{
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/* inherit personality from parent */
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/* Make sure to be in 64bit mode */
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clear_thread_flag(TIF_IA32);
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clear_thread_flag(TIF_ADDR32);
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clear_thread_flag(TIF_X32);
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/* Ensure the corresponding mm is not marked. */
|
|
if (current->mm)
|
|
current->mm->context.ia32_compat = 0;
|
|
|
|
/* TBD: overwrites user setup. Should have two bits.
|
|
But 64bit processes have always behaved this way,
|
|
so it's not too bad. The main problem is just that
|
|
32bit childs are affected again. */
|
|
current->personality &= ~READ_IMPLIES_EXEC;
|
|
}
|
|
|
|
void set_personality_ia32(bool x32)
|
|
{
|
|
/* inherit personality from parent */
|
|
|
|
/* Make sure to be in 32bit mode */
|
|
set_thread_flag(TIF_ADDR32);
|
|
|
|
/* Mark the associated mm as containing 32-bit tasks. */
|
|
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 */
|
|
current_thread_info()->status &= ~TS_COMPAT;
|
|
} 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;
|
|
}
|
|
}
|
|
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;
|
|
int doit = task == current;
|
|
int cpu;
|
|
|
|
switch (code) {
|
|
case ARCH_SET_GS:
|
|
if (addr >= TASK_SIZE_OF(task))
|
|
return -EPERM;
|
|
cpu = get_cpu();
|
|
/* handle small bases via the GDT because that's faster to
|
|
switch. */
|
|
if (addr <= 0xffffffff) {
|
|
set_32bit_tls(task, GS_TLS, addr);
|
|
if (doit) {
|
|
load_TLS(&task->thread, cpu);
|
|
load_gs_index(GS_TLS_SEL);
|
|
}
|
|
task->thread.gsindex = GS_TLS_SEL;
|
|
task->thread.gs = 0;
|
|
} else {
|
|
task->thread.gsindex = 0;
|
|
task->thread.gs = addr;
|
|
if (doit) {
|
|
load_gs_index(0);
|
|
ret = wrmsrl_safe(MSR_KERNEL_GS_BASE, addr);
|
|
}
|
|
}
|
|
put_cpu();
|
|
break;
|
|
case ARCH_SET_FS:
|
|
/* Not strictly needed for fs, but do it for symmetry
|
|
with gs */
|
|
if (addr >= TASK_SIZE_OF(task))
|
|
return -EPERM;
|
|
cpu = get_cpu();
|
|
/* handle small bases via the GDT because that's faster to
|
|
switch. */
|
|
if (addr <= 0xffffffff) {
|
|
set_32bit_tls(task, FS_TLS, addr);
|
|
if (doit) {
|
|
load_TLS(&task->thread, cpu);
|
|
loadsegment(fs, FS_TLS_SEL);
|
|
}
|
|
task->thread.fsindex = FS_TLS_SEL;
|
|
task->thread.fs = 0;
|
|
} else {
|
|
task->thread.fsindex = 0;
|
|
task->thread.fs = addr;
|
|
if (doit) {
|
|
/* set the selector to 0 to not confuse
|
|
__switch_to */
|
|
loadsegment(fs, 0);
|
|
ret = wrmsrl_safe(MSR_FS_BASE, addr);
|
|
}
|
|
}
|
|
put_cpu();
|
|
break;
|
|
case ARCH_GET_FS: {
|
|
unsigned long base;
|
|
if (task->thread.fsindex == FS_TLS_SEL)
|
|
base = read_32bit_tls(task, FS_TLS);
|
|
else if (doit)
|
|
rdmsrl(MSR_FS_BASE, base);
|
|
else
|
|
base = task->thread.fs;
|
|
ret = put_user(base, (unsigned long __user *)addr);
|
|
break;
|
|
}
|
|
case ARCH_GET_GS: {
|
|
unsigned long base;
|
|
unsigned gsindex;
|
|
if (task->thread.gsindex == GS_TLS_SEL)
|
|
base = read_32bit_tls(task, GS_TLS);
|
|
else if (doit) {
|
|
savesegment(gs, gsindex);
|
|
if (gsindex)
|
|
rdmsrl(MSR_KERNEL_GS_BASE, base);
|
|
else
|
|
base = task->thread.gs;
|
|
} else
|
|
base = task->thread.gs;
|
|
ret = put_user(base, (unsigned long __user *)addr);
|
|
break;
|
|
}
|
|
|
|
default:
|
|
ret = -EINVAL;
|
|
break;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
long sys_arch_prctl(int code, unsigned long addr)
|
|
{
|
|
return do_arch_prctl(current, code, addr);
|
|
}
|
|
|
|
unsigned long KSTK_ESP(struct task_struct *task)
|
|
{
|
|
return task_pt_regs(task)->sp;
|
|
}
|