// SPDX-License-Identifier: GPL-2.0 /* * Ptrace user space interface. * * Copyright IBM Corp. 1999, 2010 * Author(s): Denis Joseph Barrow * Martin Schwidefsky (schwidefsky@de.ibm.com) */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "entry.h" #ifdef CONFIG_COMPAT #include "compat_ptrace.h" #endif #define CREATE_TRACE_POINTS #include void update_cr_regs(struct task_struct *task) { struct pt_regs *regs = task_pt_regs(task); struct thread_struct *thread = &task->thread; struct per_regs old, new; union ctlreg0 cr0_old, cr0_new; union ctlreg2 cr2_old, cr2_new; int cr0_changed, cr2_changed; __ctl_store(cr0_old.val, 0, 0); __ctl_store(cr2_old.val, 2, 2); cr0_new = cr0_old; cr2_new = cr2_old; /* Take care of the enable/disable of transactional execution. */ if (MACHINE_HAS_TE) { /* Set or clear transaction execution TXC bit 8. */ cr0_new.tcx = 1; if (task->thread.per_flags & PER_FLAG_NO_TE) cr0_new.tcx = 0; /* Set or clear transaction execution TDC bits 62 and 63. */ cr2_new.tdc = 0; if (task->thread.per_flags & PER_FLAG_TE_ABORT_RAND) { if (task->thread.per_flags & PER_FLAG_TE_ABORT_RAND_TEND) cr2_new.tdc = 1; else cr2_new.tdc = 2; } } /* Take care of enable/disable of guarded storage. */ if (MACHINE_HAS_GS) { cr2_new.gse = 0; if (task->thread.gs_cb) cr2_new.gse = 1; } /* Load control register 0/2 iff changed */ cr0_changed = cr0_new.val != cr0_old.val; cr2_changed = cr2_new.val != cr2_old.val; if (cr0_changed) __ctl_load(cr0_new.val, 0, 0); if (cr2_changed) __ctl_load(cr2_new.val, 2, 2); /* Copy user specified PER registers */ new.control = thread->per_user.control; new.start = thread->per_user.start; new.end = thread->per_user.end; /* merge TIF_SINGLE_STEP into user specified PER registers. */ if (test_tsk_thread_flag(task, TIF_SINGLE_STEP) || test_tsk_thread_flag(task, TIF_UPROBE_SINGLESTEP)) { if (test_tsk_thread_flag(task, TIF_BLOCK_STEP)) new.control |= PER_EVENT_BRANCH; else new.control |= PER_EVENT_IFETCH; new.control |= PER_CONTROL_SUSPENSION; new.control |= PER_EVENT_TRANSACTION_END; if (test_tsk_thread_flag(task, TIF_UPROBE_SINGLESTEP)) new.control |= PER_EVENT_IFETCH; new.start = 0; new.end = -1UL; } /* Take care of the PER enablement bit in the PSW. */ if (!(new.control & PER_EVENT_MASK)) { regs->psw.mask &= ~PSW_MASK_PER; return; } regs->psw.mask |= PSW_MASK_PER; __ctl_store(old, 9, 11); if (memcmp(&new, &old, sizeof(struct per_regs)) != 0) __ctl_load(new, 9, 11); } void user_enable_single_step(struct task_struct *task) { clear_tsk_thread_flag(task, TIF_BLOCK_STEP); set_tsk_thread_flag(task, TIF_SINGLE_STEP); } void user_disable_single_step(struct task_struct *task) { clear_tsk_thread_flag(task, TIF_BLOCK_STEP); clear_tsk_thread_flag(task, TIF_SINGLE_STEP); } void user_enable_block_step(struct task_struct *task) { set_tsk_thread_flag(task, TIF_SINGLE_STEP); set_tsk_thread_flag(task, TIF_BLOCK_STEP); } /* * Called by kernel/ptrace.c when detaching.. * * Clear all debugging related fields. */ void ptrace_disable(struct task_struct *task) { memset(&task->thread.per_user, 0, sizeof(task->thread.per_user)); memset(&task->thread.per_event, 0, sizeof(task->thread.per_event)); clear_tsk_thread_flag(task, TIF_SINGLE_STEP); clear_pt_regs_flag(task_pt_regs(task), PIF_PER_TRAP); task->thread.per_flags = 0; } #define __ADDR_MASK 7 static inline unsigned long __peek_user_per(struct task_struct *child, addr_t addr) { struct per_struct_kernel *dummy = NULL; if (addr == (addr_t) &dummy->cr9) /* Control bits of the active per set. */ return test_thread_flag(TIF_SINGLE_STEP) ? PER_EVENT_IFETCH : child->thread.per_user.control; else if (addr == (addr_t) &dummy->cr10) /* Start address of the active per set. */ return test_thread_flag(TIF_SINGLE_STEP) ? 0 : child->thread.per_user.start; else if (addr == (addr_t) &dummy->cr11) /* End address of the active per set. */ return test_thread_flag(TIF_SINGLE_STEP) ? -1UL : child->thread.per_user.end; else if (addr == (addr_t) &dummy->bits) /* Single-step bit. */ return test_thread_flag(TIF_SINGLE_STEP) ? (1UL << (BITS_PER_LONG - 1)) : 0; else if (addr == (addr_t) &dummy->starting_addr) /* Start address of the user specified per set. */ return child->thread.per_user.start; else if (addr == (addr_t) &dummy->ending_addr) /* End address of the user specified per set. */ return child->thread.per_user.end; else if (addr == (addr_t) &dummy->perc_atmid) /* PER code, ATMID and AI of the last PER trap */ return (unsigned long) child->thread.per_event.cause << (BITS_PER_LONG - 16); else if (addr == (addr_t) &dummy->address) /* Address of the last PER trap */ return child->thread.per_event.address; else if (addr == (addr_t) &dummy->access_id) /* Access id of the last PER trap */ return (unsigned long) child->thread.per_event.paid << (BITS_PER_LONG - 8); return 0; } /* * Read the word at offset addr from the user area of a process. The * trouble here is that the information is littered over different * locations. The process registers are found on the kernel stack, * the floating point stuff and the trace settings are stored in * the task structure. In addition the different structures in * struct user contain pad bytes that should be read as zeroes. * Lovely... */ static unsigned long __peek_user(struct task_struct *child, addr_t addr) { struct user *dummy = NULL; addr_t offset, tmp; if (addr < (addr_t) &dummy->regs.acrs) { /* * psw and gprs are stored on the stack */ tmp = *(addr_t *)((addr_t) &task_pt_regs(child)->psw + addr); if (addr == (addr_t) &dummy->regs.psw.mask) { /* Return a clean psw mask. */ tmp &= PSW_MASK_USER | PSW_MASK_RI; tmp |= PSW_USER_BITS; } } else if (addr < (addr_t) &dummy->regs.orig_gpr2) { /* * access registers are stored in the thread structure */ offset = addr - (addr_t) &dummy->regs.acrs; /* * Very special case: old & broken 64 bit gdb reading * from acrs[15]. Result is a 64 bit value. Read the * 32 bit acrs[15] value and shift it by 32. Sick... */ if (addr == (addr_t) &dummy->regs.acrs[15]) tmp = ((unsigned long) child->thread.acrs[15]) << 32; else tmp = *(addr_t *)((addr_t) &child->thread.acrs + offset); } else if (addr == (addr_t) &dummy->regs.orig_gpr2) { /* * orig_gpr2 is stored on the kernel stack */ tmp = (addr_t) task_pt_regs(child)->orig_gpr2; } else if (addr < (addr_t) &dummy->regs.fp_regs) { /* * prevent reads of padding hole between * orig_gpr2 and fp_regs on s390. */ tmp = 0; } else if (addr == (addr_t) &dummy->regs.fp_regs.fpc) { /* * floating point control reg. is in the thread structure */ tmp = child->thread.fpu.fpc; tmp <<= BITS_PER_LONG - 32; } else if (addr < (addr_t) (&dummy->regs.fp_regs + 1)) { /* * floating point regs. are either in child->thread.fpu * or the child->thread.fpu.vxrs array */ offset = addr - (addr_t) &dummy->regs.fp_regs.fprs; if (MACHINE_HAS_VX) tmp = *(addr_t *) ((addr_t) child->thread.fpu.vxrs + 2*offset); else tmp = *(addr_t *) ((addr_t) child->thread.fpu.fprs + offset); } else if (addr < (addr_t) (&dummy->regs.per_info + 1)) { /* * Handle access to the per_info structure. */ addr -= (addr_t) &dummy->regs.per_info; tmp = __peek_user_per(child, addr); } else tmp = 0; return tmp; } static int peek_user(struct task_struct *child, addr_t addr, addr_t data) { addr_t tmp, mask; /* * Stupid gdb peeks/pokes the access registers in 64 bit with * an alignment of 4. Programmers from hell... */ mask = __ADDR_MASK; if (addr >= (addr_t) &((struct user *) NULL)->regs.acrs && addr < (addr_t) &((struct user *) NULL)->regs.orig_gpr2) mask = 3; if ((addr & mask) || addr > sizeof(struct user) - __ADDR_MASK) return -EIO; tmp = __peek_user(child, addr); return put_user(tmp, (addr_t __user *) data); } static inline void __poke_user_per(struct task_struct *child, addr_t addr, addr_t data) { struct per_struct_kernel *dummy = NULL; /* * There are only three fields in the per_info struct that the * debugger user can write to. * 1) cr9: the debugger wants to set a new PER event mask * 2) starting_addr: the debugger wants to set a new starting * address to use with the PER event mask. * 3) ending_addr: the debugger wants to set a new ending * address to use with the PER event mask. * The user specified PER event mask and the start and end * addresses are used only if single stepping is not in effect. * Writes to any other field in per_info are ignored. */ if (addr == (addr_t) &dummy->cr9) /* PER event mask of the user specified per set. */ child->thread.per_user.control = data & (PER_EVENT_MASK | PER_CONTROL_MASK); else if (addr == (addr_t) &dummy->starting_addr) /* Starting address of the user specified per set. */ child->thread.per_user.start = data; else if (addr == (addr_t) &dummy->ending_addr) /* Ending address of the user specified per set. */ child->thread.per_user.end = data; } static void fixup_int_code(struct task_struct *child, addr_t data) { struct pt_regs *regs = task_pt_regs(child); int ilc = regs->int_code >> 16; u16 insn; if (ilc > 6) return; if (ptrace_access_vm(child, regs->psw.addr - (regs->int_code >> 16), &insn, sizeof(insn), FOLL_FORCE) != sizeof(insn)) return; /* double check that tracee stopped on svc instruction */ if ((insn >> 8) != 0xa) return; regs->int_code = 0x20000 | (data & 0xffff); } /* * Write a word to the user area of a process at location addr. This * operation does have an additional problem compared to peek_user. * Stores to the program status word and on the floating point * control register needs to get checked for validity. */ static int __poke_user(struct task_struct *child, addr_t addr, addr_t data) { struct user *dummy = NULL; addr_t offset; if (addr < (addr_t) &dummy->regs.acrs) { struct pt_regs *regs = task_pt_regs(child); /* * psw and gprs are stored on the stack */ if (addr == (addr_t) &dummy->regs.psw.mask) { unsigned long mask = PSW_MASK_USER; mask |= is_ri_task(child) ? PSW_MASK_RI : 0; if ((data ^ PSW_USER_BITS) & ~mask) /* Invalid psw mask. */ return -EINVAL; if ((data & PSW_MASK_ASC) == PSW_ASC_HOME) /* Invalid address-space-control bits */ return -EINVAL; if ((data & PSW_MASK_EA) && !(data & PSW_MASK_BA)) /* Invalid addressing mode bits */ return -EINVAL; } if (test_pt_regs_flag(regs, PIF_SYSCALL) && addr == offsetof(struct user, regs.gprs[2])) fixup_int_code(child, data); *(addr_t *)((addr_t) ®s->psw + addr) = data; } else if (addr < (addr_t) (&dummy->regs.orig_gpr2)) { /* * access registers are stored in the thread structure */ offset = addr - (addr_t) &dummy->regs.acrs; /* * Very special case: old & broken 64 bit gdb writing * to acrs[15] with a 64 bit value. Ignore the lower * half of the value and write the upper 32 bit to * acrs[15]. Sick... */ if (addr == (addr_t) &dummy->regs.acrs[15]) child->thread.acrs[15] = (unsigned int) (data >> 32); else *(addr_t *)((addr_t) &child->thread.acrs + offset) = data; } else if (addr == (addr_t) &dummy->regs.orig_gpr2) { /* * orig_gpr2 is stored on the kernel stack */ task_pt_regs(child)->orig_gpr2 = data; } else if (addr < (addr_t) &dummy->regs.fp_regs) { /* * prevent writes of padding hole between * orig_gpr2 and fp_regs on s390. */ return 0; } else if (addr == (addr_t) &dummy->regs.fp_regs.fpc) { /* * floating point control reg. is in the thread structure */ save_fpu_regs(); if ((unsigned int) data != 0 || test_fp_ctl(data >> (BITS_PER_LONG - 32))) return -EINVAL; child->thread.fpu.fpc = data >> (BITS_PER_LONG - 32); } else if (addr < (addr_t) (&dummy->regs.fp_regs + 1)) { /* * floating point regs. are either in child->thread.fpu * or the child->thread.fpu.vxrs array */ offset = addr - (addr_t) &dummy->regs.fp_regs.fprs; if (MACHINE_HAS_VX) *(addr_t *)((addr_t) child->thread.fpu.vxrs + 2*offset) = data; else *(addr_t *)((addr_t) child->thread.fpu.fprs + offset) = data; } else if (addr < (addr_t) (&dummy->regs.per_info + 1)) { /* * Handle access to the per_info structure. */ addr -= (addr_t) &dummy->regs.per_info; __poke_user_per(child, addr, data); } return 0; } static int poke_user(struct task_struct *child, addr_t addr, addr_t data) { addr_t mask; /* * Stupid gdb peeks/pokes the access registers in 64 bit with * an alignment of 4. Programmers from hell indeed... */ mask = __ADDR_MASK; if (addr >= (addr_t) &((struct user *) NULL)->regs.acrs && addr < (addr_t) &((struct user *) NULL)->regs.orig_gpr2) mask = 3; if ((addr & mask) || addr > sizeof(struct user) - __ADDR_MASK) return -EIO; return __poke_user(child, addr, data); } long arch_ptrace(struct task_struct *child, long request, unsigned long addr, unsigned long data) { ptrace_area parea; int copied, ret; switch (request) { case PTRACE_PEEKUSR: /* read the word at location addr in the USER area. */ return peek_user(child, addr, data); case PTRACE_POKEUSR: /* write the word at location addr in the USER area */ return poke_user(child, addr, data); case PTRACE_PEEKUSR_AREA: case PTRACE_POKEUSR_AREA: if (copy_from_user(&parea, (void __force __user *) addr, sizeof(parea))) return -EFAULT; addr = parea.kernel_addr; data = parea.process_addr; copied = 0; while (copied < parea.len) { if (request == PTRACE_PEEKUSR_AREA) ret = peek_user(child, addr, data); else { addr_t utmp; if (get_user(utmp, (addr_t __force __user *) data)) return -EFAULT; ret = poke_user(child, addr, utmp); } if (ret) return ret; addr += sizeof(unsigned long); data += sizeof(unsigned long); copied += sizeof(unsigned long); } return 0; case PTRACE_GET_LAST_BREAK: return put_user(child->thread.last_break, (unsigned long __user *)data); case PTRACE_ENABLE_TE: if (!MACHINE_HAS_TE) return -EIO; child->thread.per_flags &= ~PER_FLAG_NO_TE; return 0; case PTRACE_DISABLE_TE: if (!MACHINE_HAS_TE) return -EIO; child->thread.per_flags |= PER_FLAG_NO_TE; child->thread.per_flags &= ~PER_FLAG_TE_ABORT_RAND; return 0; case PTRACE_TE_ABORT_RAND: if (!MACHINE_HAS_TE || (child->thread.per_flags & PER_FLAG_NO_TE)) return -EIO; switch (data) { case 0UL: child->thread.per_flags &= ~PER_FLAG_TE_ABORT_RAND; break; case 1UL: child->thread.per_flags |= PER_FLAG_TE_ABORT_RAND; child->thread.per_flags |= PER_FLAG_TE_ABORT_RAND_TEND; break; case 2UL: child->thread.per_flags |= PER_FLAG_TE_ABORT_RAND; child->thread.per_flags &= ~PER_FLAG_TE_ABORT_RAND_TEND; break; default: return -EINVAL; } return 0; default: return ptrace_request(child, request, addr, data); } } #ifdef CONFIG_COMPAT /* * Now the fun part starts... a 31 bit program running in the * 31 bit emulation tracing another program. PTRACE_PEEKTEXT, * PTRACE_PEEKDATA, PTRACE_POKETEXT and PTRACE_POKEDATA are easy * to handle, the difference to the 64 bit versions of the requests * is that the access is done in multiples of 4 byte instead of * 8 bytes (sizeof(unsigned long) on 31/64 bit). * The ugly part are PTRACE_PEEKUSR, PTRACE_PEEKUSR_AREA, * PTRACE_POKEUSR and PTRACE_POKEUSR_AREA. If the traced program * is a 31 bit program too, the content of struct user can be * emulated. A 31 bit program peeking into the struct user of * a 64 bit program is a no-no. */ /* * Same as peek_user_per but for a 31 bit program. */ static inline __u32 __peek_user_per_compat(struct task_struct *child, addr_t addr) { struct compat_per_struct_kernel *dummy32 = NULL; if (addr == (addr_t) &dummy32->cr9) /* Control bits of the active per set. */ return (__u32) test_thread_flag(TIF_SINGLE_STEP) ? PER_EVENT_IFETCH : child->thread.per_user.control; else if (addr == (addr_t) &dummy32->cr10) /* Start address of the active per set. */ return (__u32) test_thread_flag(TIF_SINGLE_STEP) ? 0 : child->thread.per_user.start; else if (addr == (addr_t) &dummy32->cr11) /* End address of the active per set. */ return test_thread_flag(TIF_SINGLE_STEP) ? PSW32_ADDR_INSN : child->thread.per_user.end; else if (addr == (addr_t) &dummy32->bits) /* Single-step bit. */ return (__u32) test_thread_flag(TIF_SINGLE_STEP) ? 0x80000000 : 0; else if (addr == (addr_t) &dummy32->starting_addr) /* Start address of the user specified per set. */ return (__u32) child->thread.per_user.start; else if (addr == (addr_t) &dummy32->ending_addr) /* End address of the user specified per set. */ return (__u32) child->thread.per_user.end; else if (addr == (addr_t) &dummy32->perc_atmid) /* PER code, ATMID and AI of the last PER trap */ return (__u32) child->thread.per_event.cause << 16; else if (addr == (addr_t) &dummy32->address) /* Address of the last PER trap */ return (__u32) child->thread.per_event.address; else if (addr == (addr_t) &dummy32->access_id) /* Access id of the last PER trap */ return (__u32) child->thread.per_event.paid << 24; return 0; } /* * Same as peek_user but for a 31 bit program. */ static u32 __peek_user_compat(struct task_struct *child, addr_t addr) { struct compat_user *dummy32 = NULL; addr_t offset; __u32 tmp; if (addr < (addr_t) &dummy32->regs.acrs) { struct pt_regs *regs = task_pt_regs(child); /* * psw and gprs are stored on the stack */ if (addr == (addr_t) &dummy32->regs.psw.mask) { /* Fake a 31 bit psw mask. */ tmp = (__u32)(regs->psw.mask >> 32); tmp &= PSW32_MASK_USER | PSW32_MASK_RI; tmp |= PSW32_USER_BITS; } else if (addr == (addr_t) &dummy32->regs.psw.addr) { /* Fake a 31 bit psw address. */ tmp = (__u32) regs->psw.addr | (__u32)(regs->psw.mask & PSW_MASK_BA); } else { /* gpr 0-15 */ tmp = *(__u32 *)((addr_t) ®s->psw + addr*2 + 4); } } else if (addr < (addr_t) (&dummy32->regs.orig_gpr2)) { /* * access registers are stored in the thread structure */ offset = addr - (addr_t) &dummy32->regs.acrs; tmp = *(__u32*)((addr_t) &child->thread.acrs + offset); } else if (addr == (addr_t) (&dummy32->regs.orig_gpr2)) { /* * orig_gpr2 is stored on the kernel stack */ tmp = *(__u32*)((addr_t) &task_pt_regs(child)->orig_gpr2 + 4); } else if (addr < (addr_t) &dummy32->regs.fp_regs) { /* * prevent reads of padding hole between * orig_gpr2 and fp_regs on s390. */ tmp = 0; } else if (addr == (addr_t) &dummy32->regs.fp_regs.fpc) { /* * floating point control reg. is in the thread structure */ tmp = child->thread.fpu.fpc; } else if (addr < (addr_t) (&dummy32->regs.fp_regs + 1)) { /* * floating point regs. are either in child->thread.fpu * or the child->thread.fpu.vxrs array */ offset = addr - (addr_t) &dummy32->regs.fp_regs.fprs; if (MACHINE_HAS_VX) tmp = *(__u32 *) ((addr_t) child->thread.fpu.vxrs + 2*offset); else tmp = *(__u32 *) ((addr_t) child->thread.fpu.fprs + offset); } else if (addr < (addr_t) (&dummy32->regs.per_info + 1)) { /* * Handle access to the per_info structure. */ addr -= (addr_t) &dummy32->regs.per_info; tmp = __peek_user_per_compat(child, addr); } else tmp = 0; return tmp; } static int peek_user_compat(struct task_struct *child, addr_t addr, addr_t data) { __u32 tmp; if (!is_compat_task() || (addr & 3) || addr > sizeof(struct user) - 3) return -EIO; tmp = __peek_user_compat(child, addr); return put_user(tmp, (__u32 __user *) data); } /* * Same as poke_user_per but for a 31 bit program. */ static inline void __poke_user_per_compat(struct task_struct *child, addr_t addr, __u32 data) { struct compat_per_struct_kernel *dummy32 = NULL; if (addr == (addr_t) &dummy32->cr9) /* PER event mask of the user specified per set. */ child->thread.per_user.control = data & (PER_EVENT_MASK | PER_CONTROL_MASK); else if (addr == (addr_t) &dummy32->starting_addr) /* Starting address of the user specified per set. */ child->thread.per_user.start = data; else if (addr == (addr_t) &dummy32->ending_addr) /* Ending address of the user specified per set. */ child->thread.per_user.end = data; } /* * Same as poke_user but for a 31 bit program. */ static int __poke_user_compat(struct task_struct *child, addr_t addr, addr_t data) { struct compat_user *dummy32 = NULL; __u32 tmp = (__u32) data; addr_t offset; if (addr < (addr_t) &dummy32->regs.acrs) { struct pt_regs *regs = task_pt_regs(child); /* * psw, gprs, acrs and orig_gpr2 are stored on the stack */ if (addr == (addr_t) &dummy32->regs.psw.mask) { __u32 mask = PSW32_MASK_USER; mask |= is_ri_task(child) ? PSW32_MASK_RI : 0; /* Build a 64 bit psw mask from 31 bit mask. */ if ((tmp ^ PSW32_USER_BITS) & ~mask) /* Invalid psw mask. */ return -EINVAL; if ((data & PSW32_MASK_ASC) == PSW32_ASC_HOME) /* Invalid address-space-control bits */ return -EINVAL; regs->psw.mask = (regs->psw.mask & ~PSW_MASK_USER) | (regs->psw.mask & PSW_MASK_BA) | (__u64)(tmp & mask) << 32; } else if (addr == (addr_t) &dummy32->regs.psw.addr) { /* Build a 64 bit psw address from 31 bit address. */ regs->psw.addr = (__u64) tmp & PSW32_ADDR_INSN; /* Transfer 31 bit amode bit to psw mask. */ regs->psw.mask = (regs->psw.mask & ~PSW_MASK_BA) | (__u64)(tmp & PSW32_ADDR_AMODE); } else { if (test_pt_regs_flag(regs, PIF_SYSCALL) && addr == offsetof(struct compat_user, regs.gprs[2])) fixup_int_code(child, data); /* gpr 0-15 */ *(__u32*)((addr_t) ®s->psw + addr*2 + 4) = tmp; } } else if (addr < (addr_t) (&dummy32->regs.orig_gpr2)) { /* * access registers are stored in the thread structure */ offset = addr - (addr_t) &dummy32->regs.acrs; *(__u32*)((addr_t) &child->thread.acrs + offset) = tmp; } else if (addr == (addr_t) (&dummy32->regs.orig_gpr2)) { /* * orig_gpr2 is stored on the kernel stack */ *(__u32*)((addr_t) &task_pt_regs(child)->orig_gpr2 + 4) = tmp; } else if (addr < (addr_t) &dummy32->regs.fp_regs) { /* * prevent writess of padding hole between * orig_gpr2 and fp_regs on s390. */ return 0; } else if (addr == (addr_t) &dummy32->regs.fp_regs.fpc) { /* * floating point control reg. is in the thread structure */ save_fpu_regs(); if (test_fp_ctl(tmp)) return -EINVAL; child->thread.fpu.fpc = data; } else if (addr < (addr_t) (&dummy32->regs.fp_regs + 1)) { /* * floating point regs. are either in child->thread.fpu * or the child->thread.fpu.vxrs array */ offset = addr - (addr_t) &dummy32->regs.fp_regs.fprs; if (MACHINE_HAS_VX) *(__u32 *)((addr_t) child->thread.fpu.vxrs + 2*offset) = tmp; else *(__u32 *)((addr_t) child->thread.fpu.fprs + offset) = tmp; } else if (addr < (addr_t) (&dummy32->regs.per_info + 1)) { /* * Handle access to the per_info structure. */ addr -= (addr_t) &dummy32->regs.per_info; __poke_user_per_compat(child, addr, data); } return 0; } static int poke_user_compat(struct task_struct *child, addr_t addr, addr_t data) { if (!is_compat_task() || (addr & 3) || addr > sizeof(struct compat_user) - 3) return -EIO; return __poke_user_compat(child, addr, data); } long compat_arch_ptrace(struct task_struct *child, compat_long_t request, compat_ulong_t caddr, compat_ulong_t cdata) { unsigned long addr = caddr; unsigned long data = cdata; compat_ptrace_area parea; int copied, ret; switch (request) { case PTRACE_PEEKUSR: /* read the word at location addr in the USER area. */ return peek_user_compat(child, addr, data); case PTRACE_POKEUSR: /* write the word at location addr in the USER area */ return poke_user_compat(child, addr, data); case PTRACE_PEEKUSR_AREA: case PTRACE_POKEUSR_AREA: if (copy_from_user(&parea, (void __force __user *) addr, sizeof(parea))) return -EFAULT; addr = parea.kernel_addr; data = parea.process_addr; copied = 0; while (copied < parea.len) { if (request == PTRACE_PEEKUSR_AREA) ret = peek_user_compat(child, addr, data); else { __u32 utmp; if (get_user(utmp, (__u32 __force __user *) data)) return -EFAULT; ret = poke_user_compat(child, addr, utmp); } if (ret) return ret; addr += sizeof(unsigned int); data += sizeof(unsigned int); copied += sizeof(unsigned int); } return 0; case PTRACE_GET_LAST_BREAK: return put_user(child->thread.last_break, (unsigned int __user *)data); } return compat_ptrace_request(child, request, addr, data); } #endif asmlinkage long do_syscall_trace_enter(struct pt_regs *regs) { unsigned long mask = -1UL; long ret = -1; if (is_compat_task()) mask = 0xffffffff; /* * The sysc_tracesys code in entry.S stored the system * call number to gprs[2]. */ if (test_thread_flag(TIF_SYSCALL_TRACE) && tracehook_report_syscall_entry(regs)) { /* * Tracing decided this syscall should not happen. Skip * the system call and the system call restart handling. */ goto skip; } #ifdef CONFIG_SECCOMP /* Do the secure computing check after ptrace. */ if (unlikely(test_thread_flag(TIF_SECCOMP))) { struct seccomp_data sd; if (is_compat_task()) { sd.instruction_pointer = regs->psw.addr & 0x7fffffff; sd.arch = AUDIT_ARCH_S390; } else { sd.instruction_pointer = regs->psw.addr; sd.arch = AUDIT_ARCH_S390X; } sd.nr = regs->int_code & 0xffff; sd.args[0] = regs->orig_gpr2 & mask; sd.args[1] = regs->gprs[3] & mask; sd.args[2] = regs->gprs[4] & mask; sd.args[3] = regs->gprs[5] & mask; sd.args[4] = regs->gprs[6] & mask; sd.args[5] = regs->gprs[7] & mask; if (__secure_computing(&sd) == -1) goto skip; } #endif /* CONFIG_SECCOMP */ if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT))) trace_sys_enter(regs, regs->int_code & 0xffff); audit_syscall_entry(regs->int_code & 0xffff, regs->orig_gpr2 & mask, regs->gprs[3] &mask, regs->gprs[4] &mask, regs->gprs[5] &mask); if ((signed long)regs->gprs[2] >= NR_syscalls) { regs->gprs[2] = -ENOSYS; ret = -ENOSYS; } return regs->gprs[2]; skip: clear_pt_regs_flag(regs, PIF_SYSCALL); return ret; } asmlinkage void do_syscall_trace_exit(struct pt_regs *regs) { audit_syscall_exit(regs); if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT))) trace_sys_exit(regs, regs->gprs[2]); if (test_thread_flag(TIF_SYSCALL_TRACE)) tracehook_report_syscall_exit(regs, 0); } /* * user_regset definitions. */ static int s390_regs_get(struct task_struct *target, const struct user_regset *regset, struct membuf to) { unsigned pos; if (target == current) save_access_regs(target->thread.acrs); for (pos = 0; pos < sizeof(s390_regs); pos += sizeof(long)) membuf_store(&to, __peek_user(target, pos)); return 0; } static int s390_regs_set(struct task_struct *target, const struct user_regset *regset, unsigned int pos, unsigned int count, const void *kbuf, const void __user *ubuf) { int rc = 0; if (target == current) save_access_regs(target->thread.acrs); if (kbuf) { const unsigned long *k = kbuf; while (count > 0 && !rc) { rc = __poke_user(target, pos, *k++); count -= sizeof(*k); pos += sizeof(*k); } } else { const unsigned long __user *u = ubuf; while (count > 0 && !rc) { unsigned long word; rc = __get_user(word, u++); if (rc) break; rc = __poke_user(target, pos, word); count -= sizeof(*u); pos += sizeof(*u); } } if (rc == 0 && target == current) restore_access_regs(target->thread.acrs); return rc; } static int s390_fpregs_get(struct task_struct *target, const struct user_regset *regset, struct membuf to) { _s390_fp_regs fp_regs; if (target == current) save_fpu_regs(); fp_regs.fpc = target->thread.fpu.fpc; fpregs_store(&fp_regs, &target->thread.fpu); return membuf_write(&to, &fp_regs, sizeof(fp_regs)); } static int s390_fpregs_set(struct task_struct *target, const struct user_regset *regset, unsigned int pos, unsigned int count, const void *kbuf, const void __user *ubuf) { int rc = 0; freg_t fprs[__NUM_FPRS]; save_fpu_regs(); if (MACHINE_HAS_VX) convert_vx_to_fp(fprs, target->thread.fpu.vxrs); else memcpy(&fprs, target->thread.fpu.fprs, sizeof(fprs)); /* If setting FPC, must validate it first. */ if (count > 0 && pos < offsetof(s390_fp_regs, fprs)) { u32 ufpc[2] = { target->thread.fpu.fpc, 0 }; rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &ufpc, 0, offsetof(s390_fp_regs, fprs)); if (rc) return rc; if (ufpc[1] != 0 || test_fp_ctl(ufpc[0])) return -EINVAL; target->thread.fpu.fpc = ufpc[0]; } if (rc == 0 && count > 0) rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf, fprs, offsetof(s390_fp_regs, fprs), -1); if (rc) return rc; if (MACHINE_HAS_VX) convert_fp_to_vx(target->thread.fpu.vxrs, fprs); else memcpy(target->thread.fpu.fprs, &fprs, sizeof(fprs)); return rc; } static int s390_last_break_get(struct task_struct *target, const struct user_regset *regset, struct membuf to) { return membuf_store(&to, target->thread.last_break); } static int s390_last_break_set(struct task_struct *target, const struct user_regset *regset, unsigned int pos, unsigned int count, const void *kbuf, const void __user *ubuf) { return 0; } static int s390_tdb_get(struct task_struct *target, const struct user_regset *regset, struct membuf to) { struct pt_regs *regs = task_pt_regs(target); if (!(regs->int_code & 0x200)) return -ENODATA; return membuf_write(&to, target->thread.trap_tdb, 256); } static int s390_tdb_set(struct task_struct *target, const struct user_regset *regset, unsigned int pos, unsigned int count, const void *kbuf, const void __user *ubuf) { return 0; } static int s390_vxrs_low_get(struct task_struct *target, const struct user_regset *regset, struct membuf to) { __u64 vxrs[__NUM_VXRS_LOW]; int i; if (!MACHINE_HAS_VX) return -ENODEV; if (target == current) save_fpu_regs(); for (i = 0; i < __NUM_VXRS_LOW; i++) vxrs[i] = *((__u64 *)(target->thread.fpu.vxrs + i) + 1); return membuf_write(&to, vxrs, sizeof(vxrs)); } static int s390_vxrs_low_set(struct task_struct *target, const struct user_regset *regset, unsigned int pos, unsigned int count, const void *kbuf, const void __user *ubuf) { __u64 vxrs[__NUM_VXRS_LOW]; int i, rc; if (!MACHINE_HAS_VX) return -ENODEV; if (target == current) save_fpu_regs(); for (i = 0; i < __NUM_VXRS_LOW; i++) vxrs[i] = *((__u64 *)(target->thread.fpu.vxrs + i) + 1); rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf, vxrs, 0, -1); if (rc == 0) for (i = 0; i < __NUM_VXRS_LOW; i++) *((__u64 *)(target->thread.fpu.vxrs + i) + 1) = vxrs[i]; return rc; } static int s390_vxrs_high_get(struct task_struct *target, const struct user_regset *regset, struct membuf to) { if (!MACHINE_HAS_VX) return -ENODEV; if (target == current) save_fpu_regs(); return membuf_write(&to, target->thread.fpu.vxrs + __NUM_VXRS_LOW, __NUM_VXRS_HIGH * sizeof(__vector128)); } static int s390_vxrs_high_set(struct task_struct *target, const struct user_regset *regset, unsigned int pos, unsigned int count, const void *kbuf, const void __user *ubuf) { int rc; if (!MACHINE_HAS_VX) return -ENODEV; if (target == current) save_fpu_regs(); rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf, target->thread.fpu.vxrs + __NUM_VXRS_LOW, 0, -1); return rc; } static int s390_system_call_get(struct task_struct *target, const struct user_regset *regset, struct membuf to) { return membuf_store(&to, target->thread.system_call); } static int s390_system_call_set(struct task_struct *target, const struct user_regset *regset, unsigned int pos, unsigned int count, const void *kbuf, const void __user *ubuf) { unsigned int *data = &target->thread.system_call; return user_regset_copyin(&pos, &count, &kbuf, &ubuf, data, 0, sizeof(unsigned int)); } static int s390_gs_cb_get(struct task_struct *target, const struct user_regset *regset, struct membuf to) { struct gs_cb *data = target->thread.gs_cb; if (!MACHINE_HAS_GS) return -ENODEV; if (!data) return -ENODATA; if (target == current) save_gs_cb(data); return membuf_write(&to, data, sizeof(struct gs_cb)); } static int s390_gs_cb_set(struct task_struct *target, const struct user_regset *regset, unsigned int pos, unsigned int count, const void *kbuf, const void __user *ubuf) { struct gs_cb gs_cb = { }, *data = NULL; int rc; if (!MACHINE_HAS_GS) return -ENODEV; if (!target->thread.gs_cb) { data = kzalloc(sizeof(*data), GFP_KERNEL); if (!data) return -ENOMEM; } if (!target->thread.gs_cb) gs_cb.gsd = 25; else if (target == current) save_gs_cb(&gs_cb); else gs_cb = *target->thread.gs_cb; rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &gs_cb, 0, sizeof(gs_cb)); if (rc) { kfree(data); return -EFAULT; } preempt_disable(); if (!target->thread.gs_cb) target->thread.gs_cb = data; *target->thread.gs_cb = gs_cb; if (target == current) { __ctl_set_bit(2, 4); restore_gs_cb(target->thread.gs_cb); } preempt_enable(); return rc; } static int s390_gs_bc_get(struct task_struct *target, const struct user_regset *regset, struct membuf to) { struct gs_cb *data = target->thread.gs_bc_cb; if (!MACHINE_HAS_GS) return -ENODEV; if (!data) return -ENODATA; return membuf_write(&to, data, sizeof(struct gs_cb)); } static int s390_gs_bc_set(struct task_struct *target, const struct user_regset *regset, unsigned int pos, unsigned int count, const void *kbuf, const void __user *ubuf) { struct gs_cb *data = target->thread.gs_bc_cb; if (!MACHINE_HAS_GS) return -ENODEV; if (!data) { data = kzalloc(sizeof(*data), GFP_KERNEL); if (!data) return -ENOMEM; target->thread.gs_bc_cb = data; } return user_regset_copyin(&pos, &count, &kbuf, &ubuf, data, 0, sizeof(struct gs_cb)); } static bool is_ri_cb_valid(struct runtime_instr_cb *cb) { return (cb->rca & 0x1f) == 0 && (cb->roa & 0xfff) == 0 && (cb->rla & 0xfff) == 0xfff && cb->s == 1 && cb->k == 1 && cb->h == 0 && cb->reserved1 == 0 && cb->ps == 1 && cb->qs == 0 && cb->pc == 1 && cb->qc == 0 && cb->reserved2 == 0 && cb->reserved3 == 0 && cb->reserved4 == 0 && cb->reserved5 == 0 && cb->reserved6 == 0 && cb->reserved7 == 0 && cb->reserved8 == 0 && cb->rla >= cb->roa && cb->rca >= cb->roa && cb->rca <= cb->rla+1 && cb->m < 3; } static int s390_runtime_instr_get(struct task_struct *target, const struct user_regset *regset, struct membuf to) { struct runtime_instr_cb *data = target->thread.ri_cb; if (!test_facility(64)) return -ENODEV; if (!data) return -ENODATA; return membuf_write(&to, data, sizeof(struct runtime_instr_cb)); } static int s390_runtime_instr_set(struct task_struct *target, const struct user_regset *regset, unsigned int pos, unsigned int count, const void *kbuf, const void __user *ubuf) { struct runtime_instr_cb ri_cb = { }, *data = NULL; int rc; if (!test_facility(64)) return -ENODEV; if (!target->thread.ri_cb) { data = kzalloc(sizeof(*data), GFP_KERNEL); if (!data) return -ENOMEM; } if (target->thread.ri_cb) { if (target == current) store_runtime_instr_cb(&ri_cb); else ri_cb = *target->thread.ri_cb; } rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &ri_cb, 0, sizeof(struct runtime_instr_cb)); if (rc) { kfree(data); return -EFAULT; } if (!is_ri_cb_valid(&ri_cb)) { kfree(data); return -EINVAL; } /* * Override access key in any case, since user space should * not be able to set it, nor should it care about it. */ ri_cb.key = PAGE_DEFAULT_KEY >> 4; preempt_disable(); if (!target->thread.ri_cb) target->thread.ri_cb = data; *target->thread.ri_cb = ri_cb; if (target == current) load_runtime_instr_cb(target->thread.ri_cb); preempt_enable(); return 0; } static const struct user_regset s390_regsets[] = { { .core_note_type = NT_PRSTATUS, .n = sizeof(s390_regs) / sizeof(long), .size = sizeof(long), .align = sizeof(long), .regset_get = s390_regs_get, .set = s390_regs_set, }, { .core_note_type = NT_PRFPREG, .n = sizeof(s390_fp_regs) / sizeof(long), .size = sizeof(long), .align = sizeof(long), .regset_get = s390_fpregs_get, .set = s390_fpregs_set, }, { .core_note_type = NT_S390_SYSTEM_CALL, .n = 1, .size = sizeof(unsigned int), .align = sizeof(unsigned int), .regset_get = s390_system_call_get, .set = s390_system_call_set, }, { .core_note_type = NT_S390_LAST_BREAK, .n = 1, .size = sizeof(long), .align = sizeof(long), .regset_get = s390_last_break_get, .set = s390_last_break_set, }, { .core_note_type = NT_S390_TDB, .n = 1, .size = 256, .align = 1, .regset_get = s390_tdb_get, .set = s390_tdb_set, }, { .core_note_type = NT_S390_VXRS_LOW, .n = __NUM_VXRS_LOW, .size = sizeof(__u64), .align = sizeof(__u64), .regset_get = s390_vxrs_low_get, .set = s390_vxrs_low_set, }, { .core_note_type = NT_S390_VXRS_HIGH, .n = __NUM_VXRS_HIGH, .size = sizeof(__vector128), .align = sizeof(__vector128), .regset_get = s390_vxrs_high_get, .set = s390_vxrs_high_set, }, { .core_note_type = NT_S390_GS_CB, .n = sizeof(struct gs_cb) / sizeof(__u64), .size = sizeof(__u64), .align = sizeof(__u64), .regset_get = s390_gs_cb_get, .set = s390_gs_cb_set, }, { .core_note_type = NT_S390_GS_BC, .n = sizeof(struct gs_cb) / sizeof(__u64), .size = sizeof(__u64), .align = sizeof(__u64), .regset_get = s390_gs_bc_get, .set = s390_gs_bc_set, }, { .core_note_type = NT_S390_RI_CB, .n = sizeof(struct runtime_instr_cb) / sizeof(__u64), .size = sizeof(__u64), .align = sizeof(__u64), .regset_get = s390_runtime_instr_get, .set = s390_runtime_instr_set, }, }; static const struct user_regset_view user_s390_view = { .name = "s390x", .e_machine = EM_S390, .regsets = s390_regsets, .n = ARRAY_SIZE(s390_regsets) }; #ifdef CONFIG_COMPAT static int s390_compat_regs_get(struct task_struct *target, const struct user_regset *regset, struct membuf to) { unsigned n; if (target == current) save_access_regs(target->thread.acrs); for (n = 0; n < sizeof(s390_compat_regs); n += sizeof(compat_ulong_t)) membuf_store(&to, __peek_user_compat(target, n)); return 0; } static int s390_compat_regs_set(struct task_struct *target, const struct user_regset *regset, unsigned int pos, unsigned int count, const void *kbuf, const void __user *ubuf) { int rc = 0; if (target == current) save_access_regs(target->thread.acrs); if (kbuf) { const compat_ulong_t *k = kbuf; while (count > 0 && !rc) { rc = __poke_user_compat(target, pos, *k++); count -= sizeof(*k); pos += sizeof(*k); } } else { const compat_ulong_t __user *u = ubuf; while (count > 0 && !rc) { compat_ulong_t word; rc = __get_user(word, u++); if (rc) break; rc = __poke_user_compat(target, pos, word); count -= sizeof(*u); pos += sizeof(*u); } } if (rc == 0 && target == current) restore_access_regs(target->thread.acrs); return rc; } static int s390_compat_regs_high_get(struct task_struct *target, const struct user_regset *regset, struct membuf to) { compat_ulong_t *gprs_high; int i; gprs_high = (compat_ulong_t *)task_pt_regs(target)->gprs; for (i = 0; i < NUM_GPRS; i++, gprs_high += 2) membuf_store(&to, *gprs_high); return 0; } static int s390_compat_regs_high_set(struct task_struct *target, const struct user_regset *regset, unsigned int pos, unsigned int count, const void *kbuf, const void __user *ubuf) { compat_ulong_t *gprs_high; int rc = 0; gprs_high = (compat_ulong_t *) &task_pt_regs(target)->gprs[pos / sizeof(compat_ulong_t)]; if (kbuf) { const compat_ulong_t *k = kbuf; while (count > 0) { *gprs_high = *k++; *gprs_high += 2; count -= sizeof(*k); } } else { const compat_ulong_t __user *u = ubuf; while (count > 0 && !rc) { unsigned long word; rc = __get_user(word, u++); if (rc) break; *gprs_high = word; *gprs_high += 2; count -= sizeof(*u); } } return rc; } static int s390_compat_last_break_get(struct task_struct *target, const struct user_regset *regset, struct membuf to) { compat_ulong_t last_break = target->thread.last_break; return membuf_store(&to, (unsigned long)last_break); } static int s390_compat_last_break_set(struct task_struct *target, const struct user_regset *regset, unsigned int pos, unsigned int count, const void *kbuf, const void __user *ubuf) { return 0; } static const struct user_regset s390_compat_regsets[] = { { .core_note_type = NT_PRSTATUS, .n = sizeof(s390_compat_regs) / sizeof(compat_long_t), .size = sizeof(compat_long_t), .align = sizeof(compat_long_t), .regset_get = s390_compat_regs_get, .set = s390_compat_regs_set, }, { .core_note_type = NT_PRFPREG, .n = sizeof(s390_fp_regs) / sizeof(compat_long_t), .size = sizeof(compat_long_t), .align = sizeof(compat_long_t), .regset_get = s390_fpregs_get, .set = s390_fpregs_set, }, { .core_note_type = NT_S390_SYSTEM_CALL, .n = 1, .size = sizeof(compat_uint_t), .align = sizeof(compat_uint_t), .regset_get = s390_system_call_get, .set = s390_system_call_set, }, { .core_note_type = NT_S390_LAST_BREAK, .n = 1, .size = sizeof(long), .align = sizeof(long), .regset_get = s390_compat_last_break_get, .set = s390_compat_last_break_set, }, { .core_note_type = NT_S390_TDB, .n = 1, .size = 256, .align = 1, .regset_get = s390_tdb_get, .set = s390_tdb_set, }, { .core_note_type = NT_S390_VXRS_LOW, .n = __NUM_VXRS_LOW, .size = sizeof(__u64), .align = sizeof(__u64), .regset_get = s390_vxrs_low_get, .set = s390_vxrs_low_set, }, { .core_note_type = NT_S390_VXRS_HIGH, .n = __NUM_VXRS_HIGH, .size = sizeof(__vector128), .align = sizeof(__vector128), .regset_get = s390_vxrs_high_get, .set = s390_vxrs_high_set, }, { .core_note_type = NT_S390_HIGH_GPRS, .n = sizeof(s390_compat_regs_high) / sizeof(compat_long_t), .size = sizeof(compat_long_t), .align = sizeof(compat_long_t), .regset_get = s390_compat_regs_high_get, .set = s390_compat_regs_high_set, }, { .core_note_type = NT_S390_GS_CB, .n = sizeof(struct gs_cb) / sizeof(__u64), .size = sizeof(__u64), .align = sizeof(__u64), .regset_get = s390_gs_cb_get, .set = s390_gs_cb_set, }, { .core_note_type = NT_S390_GS_BC, .n = sizeof(struct gs_cb) / sizeof(__u64), .size = sizeof(__u64), .align = sizeof(__u64), .regset_get = s390_gs_bc_get, .set = s390_gs_bc_set, }, { .core_note_type = NT_S390_RI_CB, .n = sizeof(struct runtime_instr_cb) / sizeof(__u64), .size = sizeof(__u64), .align = sizeof(__u64), .regset_get = s390_runtime_instr_get, .set = s390_runtime_instr_set, }, }; static const struct user_regset_view user_s390_compat_view = { .name = "s390", .e_machine = EM_S390, .regsets = s390_compat_regsets, .n = ARRAY_SIZE(s390_compat_regsets) }; #endif const struct user_regset_view *task_user_regset_view(struct task_struct *task) { #ifdef CONFIG_COMPAT if (test_tsk_thread_flag(task, TIF_31BIT)) return &user_s390_compat_view; #endif return &user_s390_view; } static const char *gpr_names[NUM_GPRS] = { "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7", "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15", }; unsigned long regs_get_register(struct pt_regs *regs, unsigned int offset) { if (offset >= NUM_GPRS) return 0; return regs->gprs[offset]; } int regs_query_register_offset(const char *name) { unsigned long offset; if (!name || *name != 'r') return -EINVAL; if (kstrtoul(name + 1, 10, &offset)) return -EINVAL; if (offset >= NUM_GPRS) return -EINVAL; return offset; } const char *regs_query_register_name(unsigned int offset) { if (offset >= NUM_GPRS) return NULL; return gpr_names[offset]; } static int regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr) { unsigned long ksp = kernel_stack_pointer(regs); return (addr & ~(THREAD_SIZE - 1)) == (ksp & ~(THREAD_SIZE - 1)); } /** * regs_get_kernel_stack_nth() - get Nth entry of the stack * @regs:pt_regs which contains kernel stack pointer. * @n:stack entry number. * * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which * is specifined by @regs. If the @n th entry is NOT in the kernel stack, * this returns 0. */ unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n) { unsigned long addr; addr = kernel_stack_pointer(regs) + n * sizeof(long); if (!regs_within_kernel_stack(regs, addr)) return 0; return *(unsigned long *)addr; }