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authorH.J. Lu <hjl.tools@gmail.com>2012-03-05 18:32:11 -0500
committerH. Peter Anvin <hpa@zytor.com>2012-03-05 18:43:45 -0500
commit55283e2537714f9370c4ab847d170acf223daf90 (patch)
treee20a2212d4de9d91c4b986a2a8dba5197516213e
parente7084fd52ed71249ab2ce7a7d89d601c9d1f904c (diff)
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" <hjl.tools@gmail.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Cc: Roland McGrath <roland@hack.frob.com> Cc: Oleg Nesterov <oleg@redhat.com> Link: http://lkml.kernel.org/r/1329696488-16970-1-git-send-email-hpa@zytor.com
-rw-r--r--arch/x86/kernel/ptrace.c99
-rw-r--r--arch/x86/syscalls/syscall_64.tbl4
2 files changed, 101 insertions, 2 deletions
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index 50267386b766..93e7877a19c4 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,
1130 return ret; 1130 return ret;
1131} 1131}
1132 1132
1133#ifdef CONFIG_X86_X32_ABI
1134static long x32_arch_ptrace(struct task_struct *child,
1135 compat_long_t request, compat_ulong_t caddr,
1136 compat_ulong_t cdata)
1137{
1138 unsigned long addr = caddr;
1139 unsigned long data = cdata;
1140 void __user *datap = compat_ptr(data);
1141 int ret;
1142
1143 switch (request) {
1144 /* Read 32bits at location addr in the USER area. Only allow
1145 to return the lower 32bits of segment and debug registers. */
1146 case PTRACE_PEEKUSR: {
1147 u32 tmp;
1148
1149 ret = -EIO;
1150 if ((addr & (sizeof(data) - 1)) || addr >= sizeof(struct user) ||
1151 addr < offsetof(struct user_regs_struct, cs))
1152 break;
1153
1154 tmp = 0; /* Default return condition */
1155 if (addr < sizeof(struct user_regs_struct))
1156 tmp = getreg(child, addr);
1157 else if (addr >= offsetof(struct user, u_debugreg[0]) &&
1158 addr <= offsetof(struct user, u_debugreg[7])) {
1159 addr -= offsetof(struct user, u_debugreg[0]);
1160 tmp = ptrace_get_debugreg(child, addr / sizeof(data));
1161 }
1162 ret = put_user(tmp, (__u32 __user *)datap);
1163 break;
1164 }
1165
1166 /* Write the word at location addr in the USER area. Only allow
1167 to update segment and debug registers with the upper 32bits
1168 zero-extended. */
1169 case PTRACE_POKEUSR:
1170 ret = -EIO;
1171 if ((addr & (sizeof(data) - 1)) || addr >= sizeof(struct user) ||
1172 addr < offsetof(struct user_regs_struct, cs))
1173 break;
1174
1175 if (addr < sizeof(struct user_regs_struct))
1176 ret = putreg(child, addr, data);
1177 else if (addr >= offsetof(struct user, u_debugreg[0]) &&
1178 addr <= offsetof(struct user, u_debugreg[7])) {
1179 addr -= offsetof(struct user, u_debugreg[0]);
1180 ret = ptrace_set_debugreg(child,
1181 addr / sizeof(data), data);
1182 }
1183 break;
1184
1185 case PTRACE_GETREGS: /* Get all gp regs from the child. */
1186 return copy_regset_to_user(child,
1187 task_user_regset_view(current),
1188 REGSET_GENERAL,
1189 0, sizeof(struct user_regs_struct),
1190 datap);
1191
1192 case PTRACE_SETREGS: /* Set all gp regs in the child. */
1193 return copy_regset_from_user(child,
1194 task_user_regset_view(current),
1195 REGSET_GENERAL,
1196 0, sizeof(struct user_regs_struct),
1197 datap);
1198
1199 case PTRACE_GETFPREGS: /* Get the child FPU state. */
1200 return copy_regset_to_user(child,
1201 task_user_regset_view(current),
1202 REGSET_FP,
1203 0, sizeof(struct user_i387_struct),
1204 datap);
1205
1206 case PTRACE_SETFPREGS: /* Set the child FPU state. */
1207 return copy_regset_from_user(child,
1208 task_user_regset_view(current),
1209 REGSET_FP,
1210 0, sizeof(struct user_i387_struct),
1211 datap);
1212
1213 /* normal 64bit interface to access TLS data.
1214 Works just like arch_prctl, except that the arguments
1215 are reversed. */
1216 case PTRACE_ARCH_PRCTL:
1217 return do_arch_prctl(child, data, addr);
1218
1219 default:
1220 return compat_ptrace_request(child, request, addr, data);
1221 }
1222
1223 return ret;
1224}
1225#endif
1226
1133long compat_arch_ptrace(struct task_struct *child, compat_long_t request, 1227long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
1134 compat_ulong_t caddr, compat_ulong_t cdata) 1228 compat_ulong_t caddr, compat_ulong_t cdata)
1135{ 1229{
@@ -1139,6 +1233,11 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
1139 int ret; 1233 int ret;
1140 __u32 val; 1234 __u32 val;
1141 1235
1236#ifdef CONFIG_X86_X32_ABI
1237 if (!is_ia32_task())
1238 return x32_arch_ptrace(child, request, caddr, cdata);
1239#endif
1240
1142 switch (request) { 1241 switch (request) {
1143 case PTRACE_PEEKUSR: 1242 case PTRACE_PEEKUSR:
1144 ret = getreg32(child, addr, &val); 1243 ret = getreg32(child, addr, &val);
diff --git a/arch/x86/syscalls/syscall_64.tbl b/arch/x86/syscalls/syscall_64.tbl
index 0d778b800884..dd29a9ea27c5 100644
--- a/arch/x86/syscalls/syscall_64.tbl
+++ b/arch/x86/syscalls/syscall_64.tbl
@@ -107,7 +107,7 @@
10798 common getrusage sys_getrusage 10798 common getrusage sys_getrusage
10899 common sysinfo sys_sysinfo 10899 common sysinfo sys_sysinfo
109100 common times sys_times 109100 common times sys_times
110101 common ptrace sys_ptrace 110101 64 ptrace sys_ptrace
111102 common getuid sys_getuid 111102 common getuid sys_getuid
112103 common syslog sys_syslog 112103 common syslog sys_syslog
113104 common getgid sys_getgid 113104 common getgid sys_getgid
@@ -331,7 +331,7 @@
331518 x32 sendmsg compat_sys_sendmsg 331518 x32 sendmsg compat_sys_sendmsg
332519 x32 recvmsg compat_sys_recvmsg 332519 x32 recvmsg compat_sys_recvmsg
333520 x32 execve stub_x32_execve 333520 x32 execve stub_x32_execve
334# 521 available 334521 x32 ptrace compat_sys_ptrace
335522 x32 rt_sigpending sys32_rt_sigpending 335522 x32 rt_sigpending sys32_rt_sigpending
336523 x32 rt_sigtimedwait compat_sys_rt_sigtimedwait 336523 x32 rt_sigtimedwait compat_sys_rt_sigtimedwait
337524 x32 rt_sigqueueinfo sys32_rt_sigqueueinfo 337524 x32 rt_sigqueueinfo sys32_rt_sigqueueinfo