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Diffstat (limited to 'arch/powerpc/kernel/ptrace/ptrace.c')
-rw-r--r-- | arch/powerpc/kernel/ptrace/ptrace.c | 494 |
1 files changed, 494 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/ptrace/ptrace.c b/arch/powerpc/kernel/ptrace/ptrace.c new file mode 100644 index 000000000..9ea9ee513 --- /dev/null +++ b/arch/powerpc/kernel/ptrace/ptrace.c @@ -0,0 +1,494 @@ +/* + * PowerPC version + * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) + * + * Derived from "arch/m68k/kernel/ptrace.c" + * Copyright (C) 1994 by Hamish Macdonald + * Taken from linux/kernel/ptrace.c and modified for M680x0. + * linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds + * + * Modified by Cort Dougan (cort@hq.fsmlabs.com) + * and Paul Mackerras (paulus@samba.org). + * + * This file is subject to the terms and conditions of the GNU General + * Public License. See the file README.legal in the main directory of + * this archive for more details. + */ + +#include <linux/regset.h> +#include <linux/tracehook.h> +#include <linux/audit.h> +#include <linux/context_tracking.h> +#include <linux/syscalls.h> + +#include <asm/switch_to.h> +#include <asm/asm-prototypes.h> +#include <asm/debug.h> + +#define CREATE_TRACE_POINTS +#include <trace/events/syscalls.h> + +#include "ptrace-decl.h" + +/* + * Called by kernel/ptrace.c when detaching.. + * + * Make sure single step bits etc are not set. + */ +void ptrace_disable(struct task_struct *child) +{ + /* make sure the single step bit is not set. */ + user_disable_single_step(child); +} + +long arch_ptrace(struct task_struct *child, long request, + unsigned long addr, unsigned long data) +{ + int ret = -EPERM; + void __user *datavp = (void __user *) data; + unsigned long __user *datalp = datavp; + + switch (request) { + /* read the word at location addr in the USER area. */ + case PTRACE_PEEKUSR: { + unsigned long index, tmp; + + ret = -EIO; + /* convert to index and check */ +#ifdef CONFIG_PPC32 + index = addr >> 2; + if ((addr & 3) || (index > PT_FPSCR) + || (child->thread.regs == NULL)) +#else + index = addr >> 3; + if ((addr & 7) || (index > PT_FPSCR)) +#endif + break; + + CHECK_FULL_REGS(child->thread.regs); + if (index < PT_FPR0) { + ret = ptrace_get_reg(child, (int) index, &tmp); + if (ret) + break; + } else { + unsigned int fpidx = index - PT_FPR0; + + flush_fp_to_thread(child); + if (fpidx < (PT_FPSCR - PT_FPR0)) + if (IS_ENABLED(CONFIG_PPC32)) { + // On 32-bit the index we are passed refers to 32-bit words + tmp = ((u32 *)child->thread.fp_state.fpr)[fpidx]; + } else { + memcpy(&tmp, &child->thread.TS_FPR(fpidx), + sizeof(long)); + } + else + tmp = child->thread.fp_state.fpscr; + } + ret = put_user(tmp, datalp); + break; + } + + /* write the word at location addr in the USER area */ + case PTRACE_POKEUSR: { + unsigned long index; + + ret = -EIO; + /* convert to index and check */ +#ifdef CONFIG_PPC32 + index = addr >> 2; + if ((addr & 3) || (index > PT_FPSCR) + || (child->thread.regs == NULL)) +#else + index = addr >> 3; + if ((addr & 7) || (index > PT_FPSCR)) +#endif + break; + + CHECK_FULL_REGS(child->thread.regs); + if (index < PT_FPR0) { + ret = ptrace_put_reg(child, index, data); + } else { + unsigned int fpidx = index - PT_FPR0; + + flush_fp_to_thread(child); + if (fpidx < (PT_FPSCR - PT_FPR0)) + if (IS_ENABLED(CONFIG_PPC32)) { + // On 32-bit the index we are passed refers to 32-bit words + ((u32 *)child->thread.fp_state.fpr)[fpidx] = data; + } else { + memcpy(&child->thread.TS_FPR(fpidx), &data, + sizeof(long)); + } + else + child->thread.fp_state.fpscr = data; + ret = 0; + } + break; + } + + case PPC_PTRACE_GETHWDBGINFO: { + struct ppc_debug_info dbginfo; + + ppc_gethwdinfo(&dbginfo); + + if (copy_to_user(datavp, &dbginfo, + sizeof(struct ppc_debug_info))) + return -EFAULT; + return 0; + } + + case PPC_PTRACE_SETHWDEBUG: { + struct ppc_hw_breakpoint bp_info; + + if (copy_from_user(&bp_info, datavp, + sizeof(struct ppc_hw_breakpoint))) + return -EFAULT; + return ppc_set_hwdebug(child, &bp_info); + } + + case PPC_PTRACE_DELHWDEBUG: { + ret = ppc_del_hwdebug(child, data); + break; + } + + case PTRACE_GET_DEBUGREG: + ret = ptrace_get_debugreg(child, addr, datalp); + break; + + case PTRACE_SET_DEBUGREG: + ret = ptrace_set_debugreg(child, addr, data); + break; + +#ifdef CONFIG_PPC64 + case PTRACE_GETREGS64: +#endif + case PTRACE_GETREGS: /* Get all pt_regs from the child. */ + return copy_regset_to_user(child, &user_ppc_native_view, + REGSET_GPR, + 0, sizeof(struct user_pt_regs), + datavp); + +#ifdef CONFIG_PPC64 + case PTRACE_SETREGS64: +#endif + case PTRACE_SETREGS: /* Set all gp regs in the child. */ + return copy_regset_from_user(child, &user_ppc_native_view, + REGSET_GPR, + 0, sizeof(struct user_pt_regs), + datavp); + + case PTRACE_GETFPREGS: /* Get the child FPU state (FPR0...31 + FPSCR) */ + return copy_regset_to_user(child, &user_ppc_native_view, + REGSET_FPR, + 0, sizeof(elf_fpregset_t), + datavp); + + case PTRACE_SETFPREGS: /* Set the child FPU state (FPR0...31 + FPSCR) */ + return copy_regset_from_user(child, &user_ppc_native_view, + REGSET_FPR, + 0, sizeof(elf_fpregset_t), + datavp); + +#ifdef CONFIG_ALTIVEC + case PTRACE_GETVRREGS: + return copy_regset_to_user(child, &user_ppc_native_view, + REGSET_VMX, + 0, (33 * sizeof(vector128) + + sizeof(u32)), + datavp); + + case PTRACE_SETVRREGS: + return copy_regset_from_user(child, &user_ppc_native_view, + REGSET_VMX, + 0, (33 * sizeof(vector128) + + sizeof(u32)), + datavp); +#endif +#ifdef CONFIG_VSX + case PTRACE_GETVSRREGS: + return copy_regset_to_user(child, &user_ppc_native_view, + REGSET_VSX, + 0, 32 * sizeof(double), + datavp); + + case PTRACE_SETVSRREGS: + return copy_regset_from_user(child, &user_ppc_native_view, + REGSET_VSX, + 0, 32 * sizeof(double), + datavp); +#endif +#ifdef CONFIG_SPE + case PTRACE_GETEVRREGS: + /* Get the child spe register state. */ + return copy_regset_to_user(child, &user_ppc_native_view, + REGSET_SPE, 0, 35 * sizeof(u32), + datavp); + + case PTRACE_SETEVRREGS: + /* Set the child spe register state. */ + return copy_regset_from_user(child, &user_ppc_native_view, + REGSET_SPE, 0, 35 * sizeof(u32), + datavp); +#endif + + default: + ret = ptrace_request(child, request, addr, data); + break; + } + return ret; +} + +#ifdef CONFIG_SECCOMP +static int do_seccomp(struct pt_regs *regs) +{ + if (!test_thread_flag(TIF_SECCOMP)) + return 0; + + /* + * The ABI we present to seccomp tracers is that r3 contains + * the syscall return value and orig_gpr3 contains the first + * syscall parameter. This is different to the ptrace ABI where + * both r3 and orig_gpr3 contain the first syscall parameter. + */ + regs->gpr[3] = -ENOSYS; + + /* + * We use the __ version here because we have already checked + * TIF_SECCOMP. If this fails, there is nothing left to do, we + * have already loaded -ENOSYS into r3, or seccomp has put + * something else in r3 (via SECCOMP_RET_ERRNO/TRACE). + */ + if (__secure_computing(NULL)) + return -1; + + /* + * The syscall was allowed by seccomp, restore the register + * state to what audit expects. + * Note that we use orig_gpr3, which means a seccomp tracer can + * modify the first syscall parameter (in orig_gpr3) and also + * allow the syscall to proceed. + */ + regs->gpr[3] = regs->orig_gpr3; + + return 0; +} +#else +static inline int do_seccomp(struct pt_regs *regs) { return 0; } +#endif /* CONFIG_SECCOMP */ + +/** + * do_syscall_trace_enter() - Do syscall tracing on kernel entry. + * @regs: the pt_regs of the task to trace (current) + * + * Performs various types of tracing on syscall entry. This includes seccomp, + * ptrace, syscall tracepoints and audit. + * + * The pt_regs are potentially visible to userspace via ptrace, so their + * contents is ABI. + * + * One or more of the tracers may modify the contents of pt_regs, in particular + * to modify arguments or even the syscall number itself. + * + * It's also possible that a tracer can choose to reject the system call. In + * that case this function will return an illegal syscall number, and will put + * an appropriate return value in regs->r3. + * + * Return: the (possibly changed) syscall number. + */ +long do_syscall_trace_enter(struct pt_regs *regs) +{ + u32 flags; + + user_exit(); + + flags = READ_ONCE(current_thread_info()->flags) & + (_TIF_SYSCALL_EMU | _TIF_SYSCALL_TRACE); + + if (flags) { + int rc = tracehook_report_syscall_entry(regs); + + if (unlikely(flags & _TIF_SYSCALL_EMU)) { + /* + * A nonzero return code from + * tracehook_report_syscall_entry() tells us to prevent + * the syscall execution, but we are not going to + * execute it anyway. + * + * Returning -1 will skip the syscall execution. We want + * to avoid clobbering any registers, so we don't goto + * the skip label below. + */ + return -1; + } + + if (rc) { + /* + * The tracer decided to abort the syscall. Note that + * the tracer may also just change regs->gpr[0] to an + * invalid syscall number, that is handled below on the + * exit path. + */ + goto skip; + } + } + + /* Run seccomp after ptrace; allow it to set gpr[3]. */ + if (do_seccomp(regs)) + return -1; + + /* Avoid trace and audit when syscall is invalid. */ + if (regs->gpr[0] >= NR_syscalls) + goto skip; + + if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT))) + trace_sys_enter(regs, regs->gpr[0]); + + if (!is_32bit_task()) + audit_syscall_entry(regs->gpr[0], regs->gpr[3], regs->gpr[4], + regs->gpr[5], regs->gpr[6]); + else + audit_syscall_entry(regs->gpr[0], + regs->gpr[3] & 0xffffffff, + regs->gpr[4] & 0xffffffff, + regs->gpr[5] & 0xffffffff, + regs->gpr[6] & 0xffffffff); + + /* Return the possibly modified but valid syscall number */ + return regs->gpr[0]; + +skip: + /* + * If we are aborting explicitly, or if the syscall number is + * now invalid, set the return value to -ENOSYS. + */ + regs->gpr[3] = -ENOSYS; + return -1; +} + +void do_syscall_trace_leave(struct pt_regs *regs) +{ + int step; + + audit_syscall_exit(regs); + + if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT))) + trace_sys_exit(regs, regs->result); + + step = test_thread_flag(TIF_SINGLESTEP); + if (step || test_thread_flag(TIF_SYSCALL_TRACE)) + tracehook_report_syscall_exit(regs, step); + + user_enter(); +} + +void __init pt_regs_check(void); + +/* + * Dummy function, its purpose is to break the build if struct pt_regs and + * struct user_pt_regs don't match. + */ +void __init pt_regs_check(void) +{ + BUILD_BUG_ON(offsetof(struct pt_regs, gpr) != + offsetof(struct user_pt_regs, gpr)); + BUILD_BUG_ON(offsetof(struct pt_regs, nip) != + offsetof(struct user_pt_regs, nip)); + BUILD_BUG_ON(offsetof(struct pt_regs, msr) != + offsetof(struct user_pt_regs, msr)); + BUILD_BUG_ON(offsetof(struct pt_regs, msr) != + offsetof(struct user_pt_regs, msr)); + BUILD_BUG_ON(offsetof(struct pt_regs, orig_gpr3) != + offsetof(struct user_pt_regs, orig_gpr3)); + BUILD_BUG_ON(offsetof(struct pt_regs, ctr) != + offsetof(struct user_pt_regs, ctr)); + BUILD_BUG_ON(offsetof(struct pt_regs, link) != + offsetof(struct user_pt_regs, link)); + BUILD_BUG_ON(offsetof(struct pt_regs, xer) != + offsetof(struct user_pt_regs, xer)); + BUILD_BUG_ON(offsetof(struct pt_regs, ccr) != + offsetof(struct user_pt_regs, ccr)); +#ifdef __powerpc64__ + BUILD_BUG_ON(offsetof(struct pt_regs, softe) != + offsetof(struct user_pt_regs, softe)); +#else + BUILD_BUG_ON(offsetof(struct pt_regs, mq) != + offsetof(struct user_pt_regs, mq)); +#endif + BUILD_BUG_ON(offsetof(struct pt_regs, trap) != + offsetof(struct user_pt_regs, trap)); + BUILD_BUG_ON(offsetof(struct pt_regs, dar) != + offsetof(struct user_pt_regs, dar)); + BUILD_BUG_ON(offsetof(struct pt_regs, dsisr) != + offsetof(struct user_pt_regs, dsisr)); + BUILD_BUG_ON(offsetof(struct pt_regs, result) != + offsetof(struct user_pt_regs, result)); + + BUILD_BUG_ON(sizeof(struct user_pt_regs) > sizeof(struct pt_regs)); + + // Now check that the pt_regs offsets match the uapi #defines + #define CHECK_REG(_pt, _reg) \ + BUILD_BUG_ON(_pt != (offsetof(struct user_pt_regs, _reg) / \ + sizeof(unsigned long))); + + CHECK_REG(PT_R0, gpr[0]); + CHECK_REG(PT_R1, gpr[1]); + CHECK_REG(PT_R2, gpr[2]); + CHECK_REG(PT_R3, gpr[3]); + CHECK_REG(PT_R4, gpr[4]); + CHECK_REG(PT_R5, gpr[5]); + CHECK_REG(PT_R6, gpr[6]); + CHECK_REG(PT_R7, gpr[7]); + CHECK_REG(PT_R8, gpr[8]); + CHECK_REG(PT_R9, gpr[9]); + CHECK_REG(PT_R10, gpr[10]); + CHECK_REG(PT_R11, gpr[11]); + CHECK_REG(PT_R12, gpr[12]); + CHECK_REG(PT_R13, gpr[13]); + CHECK_REG(PT_R14, gpr[14]); + CHECK_REG(PT_R15, gpr[15]); + CHECK_REG(PT_R16, gpr[16]); + CHECK_REG(PT_R17, gpr[17]); + CHECK_REG(PT_R18, gpr[18]); + CHECK_REG(PT_R19, gpr[19]); + CHECK_REG(PT_R20, gpr[20]); + CHECK_REG(PT_R21, gpr[21]); + CHECK_REG(PT_R22, gpr[22]); + CHECK_REG(PT_R23, gpr[23]); + CHECK_REG(PT_R24, gpr[24]); + CHECK_REG(PT_R25, gpr[25]); + CHECK_REG(PT_R26, gpr[26]); + CHECK_REG(PT_R27, gpr[27]); + CHECK_REG(PT_R28, gpr[28]); + CHECK_REG(PT_R29, gpr[29]); + CHECK_REG(PT_R30, gpr[30]); + CHECK_REG(PT_R31, gpr[31]); + CHECK_REG(PT_NIP, nip); + CHECK_REG(PT_MSR, msr); + CHECK_REG(PT_ORIG_R3, orig_gpr3); + CHECK_REG(PT_CTR, ctr); + CHECK_REG(PT_LNK, link); + CHECK_REG(PT_XER, xer); + CHECK_REG(PT_CCR, ccr); +#ifdef CONFIG_PPC64 + CHECK_REG(PT_SOFTE, softe); +#else + CHECK_REG(PT_MQ, mq); +#endif + CHECK_REG(PT_TRAP, trap); + CHECK_REG(PT_DAR, dar); + CHECK_REG(PT_DSISR, dsisr); + CHECK_REG(PT_RESULT, result); + #undef CHECK_REG + + BUILD_BUG_ON(PT_REGS_COUNT != sizeof(struct user_pt_regs) / sizeof(unsigned long)); + + /* + * PT_DSCR isn't a real reg, but it's important that it doesn't overlap the + * real registers. + */ + BUILD_BUG_ON(PT_DSCR < sizeof(struct user_pt_regs) / sizeof(unsigned long)); + + // ptrace_get/put_fpr() rely on PPC32 and VSX being incompatible + BUILD_BUG_ON(IS_ENABLED(CONFIG_PPC32) && IS_ENABLED(CONFIG_VSX)); +} |