From 55283e2537714f9370c4ab847d170acf223daf90 Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Mon, 5 Mar 2012 15:32:11 -0800 Subject: [PATCH] x32: Add ptrace for x32 X32 ptrace is a hybrid of 64bit ptrace and compat ptrace with 32bit address and longs. It use 64bit ptrace to access the full 64bit registers. PTRACE_PEEKUSR and PTRACE_POKEUSR are only allowed to access segment and debug registers. PTRACE_PEEKUSR returns the lower 32bits and PTRACE_POKEUSR zero-extends 32bit value to 64bit. It works since the upper 32bits of segment and debug registers of x32 process are always zero. GDB only uses PTRACE_PEEKUSR and PTRACE_POKEUSR to access segment and debug registers. [ hpa: changed TIF_X32 test to use !is_ia32_task() instead, and moved the system call number to the now-unused 521 slot. ] Signed-off-by: "H.J. Lu" Signed-off-by: H. Peter Anvin Cc: Roland McGrath Cc: Oleg Nesterov Link: http://lkml.kernel.org/r/1329696488-16970-1-git-send-email-hpa@zytor.com --- arch/x86/kernel/ptrace.c | 99 ++++++++++++++++++++++++++++++++++++++++ arch/x86/syscalls/syscall_64.tbl | 4 +- 2 files changed, 101 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c index 5026738..93e7877a 100644 --- a/arch/x86/kernel/ptrace.c +++ b/arch/x86/kernel/ptrace.c @@ -1130,6 +1130,100 @@ static int genregs32_set(struct task_struct *target, return ret; } +#ifdef CONFIG_X86_X32_ABI +static long x32_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; + void __user *datap = compat_ptr(data); + int ret; + + switch (request) { + /* Read 32bits at location addr in the USER area. Only allow + to return the lower 32bits of segment and debug registers. */ + case PTRACE_PEEKUSR: { + u32 tmp; + + ret = -EIO; + if ((addr & (sizeof(data) - 1)) || addr >= sizeof(struct user) || + addr < offsetof(struct user_regs_struct, cs)) + break; + + tmp = 0; /* Default return condition */ + if (addr < sizeof(struct user_regs_struct)) + tmp = getreg(child, addr); + else if (addr >= offsetof(struct user, u_debugreg[0]) && + addr <= offsetof(struct user, u_debugreg[7])) { + addr -= offsetof(struct user, u_debugreg[0]); + tmp = ptrace_get_debugreg(child, addr / sizeof(data)); + } + ret = put_user(tmp, (__u32 __user *)datap); + break; + } + + /* Write the word at location addr in the USER area. Only allow + to update segment and debug registers with the upper 32bits + zero-extended. */ + case PTRACE_POKEUSR: + ret = -EIO; + if ((addr & (sizeof(data) - 1)) || addr >= sizeof(struct user) || + addr < offsetof(struct user_regs_struct, cs)) + break; + + if (addr < sizeof(struct user_regs_struct)) + ret = putreg(child, addr, data); + else if (addr >= offsetof(struct user, u_debugreg[0]) && + addr <= offsetof(struct user, u_debugreg[7])) { + addr -= offsetof(struct user, u_debugreg[0]); + ret = ptrace_set_debugreg(child, + addr / sizeof(data), data); + } + break; + + case PTRACE_GETREGS: /* Get all gp regs from the child. */ + return copy_regset_to_user(child, + task_user_regset_view(current), + REGSET_GENERAL, + 0, sizeof(struct user_regs_struct), + datap); + + case PTRACE_SETREGS: /* Set all gp regs in the child. */ + return copy_regset_from_user(child, + task_user_regset_view(current), + REGSET_GENERAL, + 0, sizeof(struct user_regs_struct), + datap); + + case PTRACE_GETFPREGS: /* Get the child FPU state. */ + return copy_regset_to_user(child, + task_user_regset_view(current), + REGSET_FP, + 0, sizeof(struct user_i387_struct), + datap); + + case PTRACE_SETFPREGS: /* Set the child FPU state. */ + return copy_regset_from_user(child, + task_user_regset_view(current), + REGSET_FP, + 0, sizeof(struct user_i387_struct), + datap); + + /* normal 64bit interface to access TLS data. + Works just like arch_prctl, except that the arguments + are reversed. */ + case PTRACE_ARCH_PRCTL: + return do_arch_prctl(child, data, addr); + + default: + return compat_ptrace_request(child, request, addr, data); + } + + return ret; +} +#endif + long compat_arch_ptrace(struct task_struct *child, compat_long_t request, compat_ulong_t caddr, compat_ulong_t cdata) { @@ -1139,6 +1233,11 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request, int ret; __u32 val; +#ifdef CONFIG_X86_X32_ABI + if (!is_ia32_task()) + return x32_arch_ptrace(child, request, caddr, cdata); +#endif + switch (request) { case PTRACE_PEEKUSR: ret = getreg32(child, addr, &val); diff --git a/arch/x86/syscalls/syscall_64.tbl b/arch/x86/syscalls/syscall_64.tbl index 0d778b8..dd29a9e 100644 --- a/arch/x86/syscalls/syscall_64.tbl +++ b/arch/x86/syscalls/syscall_64.tbl @@ -107,7 +107,7 @@ 98 common getrusage sys_getrusage 99 common sysinfo sys_sysinfo 100 common times sys_times -101 common ptrace sys_ptrace +101 64 ptrace sys_ptrace 102 common getuid sys_getuid 103 common syslog sys_syslog 104 common getgid sys_getgid @@ -331,7 +331,7 @@ 518 x32 sendmsg compat_sys_sendmsg 519 x32 recvmsg compat_sys_recvmsg 520 x32 execve stub_x32_execve -# 521 available +521 x32 ptrace compat_sys_ptrace 522 x32 rt_sigpending sys32_rt_sigpending 523 x32 rt_sigtimedwait compat_sys_rt_sigtimedwait 524 x32 rt_sigqueueinfo sys32_rt_sigqueueinfo -- 2.7.4