s390/uprobes: architecture backend for uprobes
Signed-off-by: Jan Willeke <willeke@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 47492fc..608adfb 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -58,6 +58,9 @@
config PCI_QUIRKS
def_bool n
+config ARCH_SUPPORTS_UPROBES
+ def_bool 64BIT
+
config S390
def_bool y
select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
diff --git a/arch/s390/include/asm/ptrace.h b/arch/s390/include/asm/ptrace.h
index 55d69dd..be317fe 100644
--- a/arch/s390/include/asm/ptrace.h
+++ b/arch/s390/include/asm/ptrace.h
@@ -161,6 +161,12 @@
return regs->gprs[2];
}
+static inline void instruction_pointer_set(struct pt_regs *regs,
+ unsigned long val)
+{
+ regs->psw.addr = val | PSW_ADDR_AMODE;
+}
+
int regs_query_register_offset(const char *name);
const char *regs_query_register_name(unsigned int offset);
unsigned long regs_get_register(struct pt_regs *regs, unsigned int offset);
diff --git a/arch/s390/include/asm/thread_info.h b/arch/s390/include/asm/thread_info.h
index b833e9c..4d62fd5 100644
--- a/arch/s390/include/asm/thread_info.h
+++ b/arch/s390/include/asm/thread_info.h
@@ -84,11 +84,13 @@
#define TIF_SYSCALL_AUDIT 4 /* syscall auditing active */
#define TIF_SECCOMP 5 /* secure computing */
#define TIF_SYSCALL_TRACEPOINT 6 /* syscall tracepoint instrumentation */
+#define TIF_UPROBE 7 /* breakpointed or single-stepping */
#define TIF_31BIT 16 /* 32bit process */
#define TIF_MEMDIE 17 /* is terminating due to OOM killer */
#define TIF_RESTORE_SIGMASK 18 /* restore signal mask in do_signal() */
#define TIF_SINGLE_STEP 19 /* This task is single stepped */
#define TIF_BLOCK_STEP 20 /* This task is block stepped */
+#define TIF_UPROBE_SINGLESTEP 21 /* This task is uprobe single stepped */
#define _TIF_NOTIFY_RESUME (1<<TIF_NOTIFY_RESUME)
#define _TIF_SIGPENDING (1<<TIF_SIGPENDING)
@@ -97,6 +99,7 @@
#define _TIF_SYSCALL_AUDIT (1<<TIF_SYSCALL_AUDIT)
#define _TIF_SECCOMP (1<<TIF_SECCOMP)
#define _TIF_SYSCALL_TRACEPOINT (1<<TIF_SYSCALL_TRACEPOINT)
+#define _TIF_UPROBE (1<<TIF_UPROBE)
#define _TIF_31BIT (1<<TIF_31BIT)
#define _TIF_SINGLE_STEP (1<<TIF_SINGLE_STEP)
diff --git a/arch/s390/include/asm/uprobes.h b/arch/s390/include/asm/uprobes.h
new file mode 100644
index 0000000..1411dff
--- /dev/null
+++ b/arch/s390/include/asm/uprobes.h
@@ -0,0 +1,42 @@
+/*
+ * User-space Probes (UProbes) for s390
+ *
+ * Copyright IBM Corp. 2014
+ * Author(s): Jan Willeke,
+ */
+
+#ifndef _ASM_UPROBES_H
+#define _ASM_UPROBES_H
+
+#include <linux/notifier.h>
+
+typedef u16 uprobe_opcode_t;
+
+#define UPROBE_XOL_SLOT_BYTES 256 /* cache aligned */
+
+#define UPROBE_SWBP_INSN 0x0002
+#define UPROBE_SWBP_INSN_SIZE 2
+
+struct arch_uprobe {
+ union{
+ uprobe_opcode_t insn[3];
+ uprobe_opcode_t ixol[3];
+ };
+ unsigned int saved_per : 1;
+ unsigned int saved_int_code;
+};
+
+struct arch_uprobe_task {
+};
+
+int arch_uprobe_analyze_insn(struct arch_uprobe *aup, struct mm_struct *mm,
+ unsigned long addr);
+int arch_uprobe_pre_xol(struct arch_uprobe *aup, struct pt_regs *regs);
+int arch_uprobe_post_xol(struct arch_uprobe *aup, struct pt_regs *regs);
+bool arch_uprobe_xol_was_trapped(struct task_struct *tsk);
+int arch_uprobe_exception_notify(struct notifier_block *self, unsigned long val,
+ void *data);
+void arch_uprobe_abort_xol(struct arch_uprobe *ap, struct pt_regs *regs);
+unsigned long arch_uretprobe_hijack_return_addr(unsigned long trampoline,
+ struct pt_regs *regs);
+#endif /* _ASM_UPROBES_H */
diff --git a/arch/s390/kernel/Makefile b/arch/s390/kernel/Makefile
index d44245d..3249e1f 100644
--- a/arch/s390/kernel/Makefile
+++ b/arch/s390/kernel/Makefile
@@ -55,6 +55,7 @@
obj-$(CONFIG_FUNCTION_TRACER) += $(if $(CONFIG_64BIT),mcount64.o,mcount.o)
obj-$(CONFIG_FUNCTION_TRACER) += ftrace.o
obj-$(CONFIG_CRASH_DUMP) += crash_dump.o
+obj-$(CONFIG_UPROBES) += uprobes.o
ifdef CONFIG_64BIT
obj-$(CONFIG_PERF_EVENTS) += perf_event.o perf_cpum_cf.o perf_cpum_sf.o \
diff --git a/arch/s390/kernel/entry.h b/arch/s390/kernel/entry.h
index 1aad483..5854163 100644
--- a/arch/s390/kernel/entry.h
+++ b/arch/s390/kernel/entry.h
@@ -45,6 +45,7 @@
void translation_exception(struct pt_regs *regs);
void do_per_trap(struct pt_regs *regs);
+void do_report_trap(struct pt_regs *regs, int si_signo, int si_code, char *str);
void syscall_trace(struct pt_regs *regs, int entryexit);
void kernel_stack_overflow(struct pt_regs * regs);
void do_signal(struct pt_regs *regs);
diff --git a/arch/s390/kernel/entry64.S b/arch/s390/kernel/entry64.S
index f2e674c..7b2e03a 100644
--- a/arch/s390/kernel/entry64.S
+++ b/arch/s390/kernel/entry64.S
@@ -42,7 +42,8 @@
STACK_SIZE = 1 << STACK_SHIFT
STACK_INIT = STACK_SIZE - STACK_FRAME_OVERHEAD - __PT_SIZE
-_TIF_WORK = (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_NEED_RESCHED)
+_TIF_WORK = (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_NEED_RESCHED | \
+ _TIF_UPROBE)
_TIF_TRACE = (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | _TIF_SECCOMP | \
_TIF_SYSCALL_TRACEPOINT)
_CIF_WORK = (_CIF_MCCK_PENDING | _CIF_ASCE)
@@ -265,6 +266,10 @@
jo sysc_mcck_pending
tm __TI_flags+7(%r12),_TIF_NEED_RESCHED
jo sysc_reschedule
+#ifdef CONFIG_UPROBES
+ tm __TI_flags+7(%r12),_TIF_UPROBE
+ jo sysc_uprobe_notify
+#endif
tm __PT_FLAGS+7(%r11),_PIF_PER_TRAP
jo sysc_singlestep
tm __TI_flags+7(%r12),_TIF_SIGPENDING
@@ -323,6 +328,16 @@
jg do_notify_resume
#
+# _TIF_UPROBE is set, call uprobe_notify_resume
+#
+#ifdef CONFIG_UPROBES
+sysc_uprobe_notify:
+ lgr %r2,%r11 # pass pointer to pt_regs
+ larl %r14,sysc_return
+ jg uprobe_notify_resume
+#endif
+
+#
# _PIF_PER_TRAP is set, call do_per_trap
#
sysc_singlestep:
diff --git a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c
index 5dc7ad9..fe99d6b 100644
--- a/arch/s390/kernel/ptrace.c
+++ b/arch/s390/kernel/ptrace.c
@@ -84,7 +84,8 @@
new.end = thread->per_user.end;
/* merge TIF_SINGLE_STEP into user specified PER registers. */
- if (test_tsk_thread_flag(task, TIF_SINGLE_STEP)) {
+ 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
@@ -93,6 +94,8 @@
new.control |= PER_CONTROL_SUSPENSION;
new.control |= PER_EVENT_TRANSACTION_END;
#endif
+ if (test_tsk_thread_flag(task, TIF_UPROBE_SINGLESTEP))
+ new.control |= PER_EVENT_IFETCH;
new.start = 0;
new.end = PSW_ADDR_INSN;
}
diff --git a/arch/s390/kernel/traps.c b/arch/s390/kernel/traps.c
index c576232..e3e06a4 100644
--- a/arch/s390/kernel/traps.c
+++ b/arch/s390/kernel/traps.c
@@ -58,15 +58,10 @@
return 1;
}
-static void __kprobes do_trap(struct pt_regs *regs,
- int si_signo, int si_code, char *str)
+void do_report_trap(struct pt_regs *regs, int si_signo, int si_code, char *str)
{
siginfo_t info;
- if (notify_die(DIE_TRAP, str, regs, 0,
- regs->int_code, si_signo) == NOTIFY_STOP)
- return;
-
if (user_mode(regs)) {
info.si_signo = si_signo;
info.si_errno = 0;
@@ -90,6 +85,15 @@
}
}
+static void __kprobes do_trap(struct pt_regs *regs, int si_signo, int si_code,
+ char *str)
+{
+ if (notify_die(DIE_TRAP, str, regs, 0,
+ regs->int_code, si_signo) == NOTIFY_STOP)
+ return;
+ do_report_trap(regs, si_signo, si_code, str);
+}
+
void __kprobes do_per_trap(struct pt_regs *regs)
{
siginfo_t info;
@@ -178,6 +182,7 @@
siginfo_t info;
__u8 opcode[6];
__u16 __user *location;
+ int is_uprobe_insn = 0;
int signal = 0;
location = get_trap_ip(regs);
@@ -194,6 +199,10 @@
force_sig_info(SIGTRAP, &info, current);
} else
signal = SIGILL;
+#ifdef CONFIG_UPROBES
+ } else if (*((__u16 *) opcode) == UPROBE_SWBP_INSN) {
+ is_uprobe_insn = 1;
+#endif
#ifdef CONFIG_MATHEMU
} else if (opcode[0] == 0xb3) {
if (get_user(*((__u16 *) (opcode+2)), location+1))
@@ -219,11 +228,13 @@
#endif
} else
signal = SIGILL;
- } else {
- /*
- * If we get an illegal op in kernel mode, send it through the
- * kprobes notifier. If kprobes doesn't pick it up, SIGILL
- */
+ }
+ /*
+ * We got either an illegal op in kernel mode, or user space trapped
+ * on a uprobes illegal instruction. See if kprobes or uprobes picks
+ * it up. If not, SIGILL.
+ */
+ if (is_uprobe_insn || !user_mode(regs)) {
if (notify_die(DIE_BPT, "bpt", regs, 0,
3, SIGTRAP) != NOTIFY_STOP)
signal = SIGILL;
diff --git a/arch/s390/kernel/uprobes.c b/arch/s390/kernel/uprobes.c
new file mode 100644
index 0000000..956f4f7
--- /dev/null
+++ b/arch/s390/kernel/uprobes.c
@@ -0,0 +1,332 @@
+/*
+ * User-space Probes (UProbes) for s390
+ *
+ * Copyright IBM Corp. 2014
+ * Author(s): Jan Willeke,
+ */
+
+#include <linux/kprobes.h>
+#include <linux/uaccess.h>
+#include <linux/uprobes.h>
+#include <linux/compat.h>
+#include <linux/kdebug.h>
+#include <asm/switch_to.h>
+#include <asm/facility.h>
+#include <asm/dis.h>
+#include "entry.h"
+
+#define UPROBE_TRAP_NR UINT_MAX
+
+int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm,
+ unsigned long addr)
+{
+ return probe_is_prohibited_opcode(auprobe->insn);
+}
+
+int arch_uprobe_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
+{
+ if (psw_bits(regs->psw).eaba == PSW_AMODE_24BIT)
+ return -EINVAL;
+ if (!is_compat_task() && psw_bits(regs->psw).eaba == PSW_AMODE_31BIT)
+ return -EINVAL;
+ clear_pt_regs_flag(regs, PIF_PER_TRAP);
+ auprobe->saved_per = psw_bits(regs->psw).r;
+ auprobe->saved_int_code = regs->int_code;
+ regs->int_code = UPROBE_TRAP_NR;
+ regs->psw.addr = current->utask->xol_vaddr;
+ set_tsk_thread_flag(current, TIF_UPROBE_SINGLESTEP);
+ update_cr_regs(current);
+ return 0;
+}
+
+bool arch_uprobe_xol_was_trapped(struct task_struct *tsk)
+{
+ struct pt_regs *regs = task_pt_regs(tsk);
+
+ if (regs->int_code != UPROBE_TRAP_NR)
+ return true;
+ return false;
+}
+
+int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
+{
+ int fixup = probe_get_fixup_type(auprobe->insn);
+ struct uprobe_task *utask = current->utask;
+
+ clear_tsk_thread_flag(current, TIF_UPROBE_SINGLESTEP);
+ update_cr_regs(current);
+ psw_bits(regs->psw).r = auprobe->saved_per;
+ regs->int_code = auprobe->saved_int_code;
+
+ if (fixup & FIXUP_PSW_NORMAL)
+ regs->psw.addr += utask->vaddr - utask->xol_vaddr;
+ if (fixup & FIXUP_RETURN_REGISTER) {
+ int reg = (auprobe->insn[0] & 0xf0) >> 4;
+
+ regs->gprs[reg] += utask->vaddr - utask->xol_vaddr;
+ }
+ if (fixup & FIXUP_BRANCH_NOT_TAKEN) {
+ int ilen = insn_length(auprobe->insn[0] >> 8);
+
+ if (regs->psw.addr - utask->xol_vaddr == ilen)
+ regs->psw.addr = utask->vaddr + ilen;
+ }
+ /* If per tracing was active generate trap */
+ if (regs->psw.mask & PSW_MASK_PER)
+ do_per_trap(regs);
+ return 0;
+}
+
+int arch_uprobe_exception_notify(struct notifier_block *self, unsigned long val,
+ void *data)
+{
+ struct die_args *args = data;
+ struct pt_regs *regs = args->regs;
+
+ if (!user_mode(regs))
+ return NOTIFY_DONE;
+ if (regs->int_code & 0x200) /* Trap during transaction */
+ return NOTIFY_DONE;
+ switch (val) {
+ case DIE_BPT:
+ if (uprobe_pre_sstep_notifier(regs))
+ return NOTIFY_STOP;
+ break;
+ case DIE_SSTEP:
+ if (uprobe_post_sstep_notifier(regs))
+ return NOTIFY_STOP;
+ default:
+ break;
+ }
+ return NOTIFY_DONE;
+}
+
+void arch_uprobe_abort_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
+{
+ clear_thread_flag(TIF_UPROBE_SINGLESTEP);
+ regs->int_code = auprobe->saved_int_code;
+ regs->psw.addr = current->utask->vaddr;
+}
+
+unsigned long arch_uretprobe_hijack_return_addr(unsigned long trampoline,
+ struct pt_regs *regs)
+{
+ unsigned long orig;
+
+ orig = regs->gprs[14];
+ regs->gprs[14] = trampoline;
+ return orig;
+}
+
+/* Instruction Emulation */
+
+static void adjust_psw_addr(psw_t *psw, unsigned long len)
+{
+ psw->addr = __rewind_psw(*psw, -len);
+}
+
+#define EMU_ILLEGAL_OP 1
+#define EMU_SPECIFICATION 2
+#define EMU_ADDRESSING 3
+
+#define emu_load_ril(ptr, output) \
+({ \
+ unsigned int mask = sizeof(*(ptr)) - 1; \
+ __typeof__(*(ptr)) input; \
+ int __rc = 0; \
+ \
+ if (!test_facility(34)) \
+ __rc = EMU_ILLEGAL_OP; \
+ else if ((u64 __force)ptr & mask) \
+ __rc = EMU_SPECIFICATION; \
+ else if (get_user(input, ptr)) \
+ __rc = EMU_ADDRESSING; \
+ else \
+ *(output) = input; \
+ __rc; \
+})
+
+#define emu_store_ril(ptr, input) \
+({ \
+ unsigned int mask = sizeof(*(ptr)) - 1; \
+ int __rc = 0; \
+ \
+ if (!test_facility(34)) \
+ __rc = EMU_ILLEGAL_OP; \
+ else if ((u64 __force)ptr & mask) \
+ __rc = EMU_SPECIFICATION; \
+ else if (put_user(*(input), ptr)) \
+ __rc = EMU_ADDRESSING; \
+ __rc; \
+})
+
+#define emu_cmp_ril(regs, ptr, cmp) \
+({ \
+ unsigned int mask = sizeof(*(ptr)) - 1; \
+ __typeof__(*(ptr)) input; \
+ int __rc = 0; \
+ \
+ if (!test_facility(34)) \
+ __rc = EMU_ILLEGAL_OP; \
+ else if ((u64 __force)ptr & mask) \
+ __rc = EMU_SPECIFICATION; \
+ else if (get_user(input, ptr)) \
+ __rc = EMU_ADDRESSING; \
+ else if (input > *(cmp)) \
+ psw_bits((regs)->psw).cc = 1; \
+ else if (input < *(cmp)) \
+ psw_bits((regs)->psw).cc = 2; \
+ else \
+ psw_bits((regs)->psw).cc = 0; \
+ __rc; \
+})
+
+struct insn_ril {
+ u8 opc0;
+ u8 reg : 4;
+ u8 opc1 : 4;
+ s32 disp;
+} __packed;
+
+union split_register {
+ u64 u64;
+ u32 u32[2];
+ u16 u16[4];
+ s64 s64;
+ s32 s32[2];
+ s16 s16[4];
+};
+
+/*
+ * pc relative instructions are emulated, since parameters may not be
+ * accessible from the xol area due to range limitations.
+ */
+static void handle_insn_ril(struct arch_uprobe *auprobe, struct pt_regs *regs)
+{
+ union split_register *rx;
+ struct insn_ril *insn;
+ unsigned int ilen;
+ void *uptr;
+ int rc = 0;
+
+ insn = (struct insn_ril *) &auprobe->insn;
+ rx = (union split_register *) ®s->gprs[insn->reg];
+ uptr = (void *)(regs->psw.addr + (insn->disp * 2));
+ ilen = insn_length(insn->opc0);
+
+ switch (insn->opc0) {
+ case 0xc0:
+ switch (insn->opc1) {
+ case 0x00: /* larl */
+ rx->u64 = (unsigned long)uptr;
+ break;
+ }
+ break;
+ case 0xc4:
+ switch (insn->opc1) {
+ case 0x02: /* llhrl */
+ rc = emu_load_ril((u16 __user *)uptr, &rx->u32[1]);
+ break;
+ case 0x04: /* lghrl */
+ rc = emu_load_ril((s16 __user *)uptr, &rx->u64);
+ break;
+ case 0x05: /* lhrl */
+ rc = emu_load_ril((s16 __user *)uptr, &rx->u32[1]);
+ break;
+ case 0x06: /* llghrl */
+ rc = emu_load_ril((u16 __user *)uptr, &rx->u64);
+ break;
+ case 0x08: /* lgrl */
+ rc = emu_load_ril((u64 __user *)uptr, &rx->u64);
+ break;
+ case 0x0c: /* lgfrl */
+ rc = emu_load_ril((s32 __user *)uptr, &rx->u64);
+ break;
+ case 0x0d: /* lrl */
+ rc = emu_load_ril((u32 __user *)uptr, &rx->u32[1]);
+ break;
+ case 0x0e: /* llgfrl */
+ rc = emu_load_ril((u32 __user *)uptr, &rx->u64);
+ break;
+ case 0x07: /* sthrl */
+ rc = emu_store_ril((u16 __user *)uptr, &rx->u16[3]);
+ break;
+ case 0x0b: /* stgrl */
+ rc = emu_store_ril((u64 __user *)uptr, &rx->u64);
+ break;
+ case 0x0f: /* strl */
+ rc = emu_store_ril((u32 __user *)uptr, &rx->u32[1]);
+ break;
+ }
+ break;
+ case 0xc6:
+ switch (insn->opc1) {
+ case 0x02: /* pfdrl */
+ if (!test_facility(34))
+ rc = EMU_ILLEGAL_OP;
+ break;
+ case 0x04: /* cghrl */
+ rc = emu_cmp_ril(regs, (s16 __user *)uptr, &rx->s64);
+ break;
+ case 0x05: /* chrl */
+ rc = emu_cmp_ril(regs, (s16 __user *)uptr, &rx->s32[1]);
+ break;
+ case 0x06: /* clghrl */
+ rc = emu_cmp_ril(regs, (u16 __user *)uptr, &rx->u64);
+ break;
+ case 0x07: /* clhrl */
+ rc = emu_cmp_ril(regs, (u16 __user *)uptr, &rx->u32[1]);
+ break;
+ case 0x08: /* cgrl */
+ rc = emu_cmp_ril(regs, (s64 __user *)uptr, &rx->s64);
+ break;
+ case 0x0a: /* clgrl */
+ rc = emu_cmp_ril(regs, (u64 __user *)uptr, &rx->u64);
+ break;
+ case 0x0c: /* cgfrl */
+ rc = emu_cmp_ril(regs, (s32 __user *)uptr, &rx->s64);
+ break;
+ case 0x0d: /* crl */
+ rc = emu_cmp_ril(regs, (s32 __user *)uptr, &rx->s32[1]);
+ break;
+ case 0x0e: /* clgfrl */
+ rc = emu_cmp_ril(regs, (u32 __user *)uptr, &rx->u64);
+ break;
+ case 0x0f: /* clrl */
+ rc = emu_cmp_ril(regs, (u32 __user *)uptr, &rx->u32[1]);
+ break;
+ }
+ break;
+ }
+ adjust_psw_addr(®s->psw, ilen);
+ switch (rc) {
+ case EMU_ILLEGAL_OP:
+ regs->int_code = ilen << 16 | 0x0001;
+ do_report_trap(regs, SIGILL, ILL_ILLOPC, NULL);
+ break;
+ case EMU_SPECIFICATION:
+ regs->int_code = ilen << 16 | 0x0006;
+ do_report_trap(regs, SIGILL, ILL_ILLOPC , NULL);
+ break;
+ case EMU_ADDRESSING:
+ regs->int_code = ilen << 16 | 0x0005;
+ do_report_trap(regs, SIGSEGV, SEGV_MAPERR, NULL);
+ break;
+ }
+}
+
+bool arch_uprobe_skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs)
+{
+ if ((psw_bits(regs->psw).eaba == PSW_AMODE_24BIT) ||
+ ((psw_bits(regs->psw).eaba == PSW_AMODE_31BIT) &&
+ !is_compat_task())) {
+ regs->psw.addr = __rewind_psw(regs->psw, UPROBE_SWBP_INSN_SIZE);
+ do_report_trap(regs, SIGILL, ILL_ILLADR, NULL);
+ return true;
+ }
+ if (probe_is_insn_relative_long(auprobe->insn)) {
+ handle_insn_ril(auprobe, regs);
+ return true;
+ }
+ return false;
+}