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s390/unwind: introduce stack unwind API 

Rework the dump_trace() stack unwinder interface to support different
unwinding algorithms. The new interface looks like this:

	struct unwind_state state;
	unwind_for_each_frame(&state, task, regs, start_stack)
		do_something(state.sp, state.ip, state.reliable);

The unwind_bc.c file contains the implementation for the classic
back-chain unwinder.

One positive side effect of the new code is it now handles ftraced
functions gracefully. It prints the real name of the return function
instead of 'return_to_handler'.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Martin Schwidefsky 2019-01-28 08:33:08 +01:00
parent 1c705ad5ef
commit 78c98f9074
16 changed files with 521 additions and 205 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

72
arch/s390/include/asm/processor.h
View File

@ -156,25 +156,6 @@ struct thread_struct {
typedef struct thread_struct thread_struct;
/*
* Stack layout of a C stack frame.
*/
#ifndef __PACK_STACK
struct stack_frame {
unsigned long back_chain;
unsigned long empty1[5];
unsigned long gprs[10];
unsigned int empty2[8];
};
#else
struct stack_frame {
unsigned long empty1[5];
unsigned int empty2[8];
unsigned long gprs[10];
unsigned long back_chain;
};
#endif
#define ARCH_MIN_TASKALIGN 8
#define INIT_THREAD { \
@ -206,11 +187,7 @@ struct mm_struct;
struct seq_file;
struct pt_regs;
typedef int (*dump_trace_func_t)(void *data, unsigned long address, int reliable);
void dump_trace(dump_trace_func_t func, void *data,
struct task_struct *task, unsigned long sp);
void show_registers(struct pt_regs *regs);
void show_cacheinfo(struct seq_file *m);
/* Free all resources held by a thread. */
@ -244,55 +221,6 @@ static __no_kasan_or_inline unsigned short stap(void)
return cpu_address;
}
#define CALL_ARGS_0() \
register unsigned long r2 asm("2")
#define CALL_ARGS_1(arg1) \
register unsigned long r2 asm("2") = (unsigned long)(arg1)
#define CALL_ARGS_2(arg1, arg2) \
CALL_ARGS_1(arg1); \
register unsigned long r3 asm("3") = (unsigned long)(arg2)
#define CALL_ARGS_3(arg1, arg2, arg3) \
CALL_ARGS_2(arg1, arg2); \
register unsigned long r4 asm("4") = (unsigned long)(arg3)
#define CALL_ARGS_4(arg1, arg2, arg3, arg4) \
CALL_ARGS_3(arg1, arg2, arg3); \
register unsigned long r4 asm("5") = (unsigned long)(arg4)
#define CALL_ARGS_5(arg1, arg2, arg3, arg4, arg5) \
CALL_ARGS_4(arg1, arg2, arg3, arg4); \
register unsigned long r4 asm("6") = (unsigned long)(arg5)
#define CALL_FMT_0 "=&d" (r2) :
#define CALL_FMT_1 "+&d" (r2) :
#define CALL_FMT_2 CALL_FMT_1 "d" (r3),
#define CALL_FMT_3 CALL_FMT_2 "d" (r4),
#define CALL_FMT_4 CALL_FMT_3 "d" (r5),
#define CALL_FMT_5 CALL_FMT_4 "d" (r6),
#define CALL_CLOBBER_5 "0", "1", "14", "cc", "memory"
#define CALL_CLOBBER_4 CALL_CLOBBER_5
#define CALL_CLOBBER_3 CALL_CLOBBER_4, "5"
#define CALL_CLOBBER_2 CALL_CLOBBER_3, "4"
#define CALL_CLOBBER_1 CALL_CLOBBER_2, "3"
#define CALL_CLOBBER_0 CALL_CLOBBER_1
#define CALL_ON_STACK(fn, stack, nr, args...) \
({ \
CALL_ARGS_##nr(args); \
unsigned long prev; \
\
asm volatile( \
" la %[_prev],0(15)\n" \
" la 15,0(%[_stack])\n" \
" stg %[_prev],%[_bc](15)\n" \
" brasl 14,%[_fn]\n" \
" la 15,0(%[_prev])\n" \
: [_prev] "=&a" (prev), CALL_FMT_##nr \
[_stack] "a" (stack), \
[_bc] "i" (offsetof(struct stack_frame, back_chain)), \
[_fn] "X" (fn) : CALL_CLOBBER_##nr); \
r2; \
})
/*
* Give up the time slice of the virtual PU.
*/

114
arch/s390/include/asm/stacktrace.h Normal file
View File

@ -0,0 +1,114 @@
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_S390_STACKTRACE_H
#define _ASM_S390_STACKTRACE_H
#include <linux/uaccess.h>
#include <linux/ptrace.h>
#include <asm/switch_to.h>
enum stack_type {
STACK_TYPE_UNKNOWN,
STACK_TYPE_TASK,
STACK_TYPE_IRQ,
STACK_TYPE_NODAT,
STACK_TYPE_RESTART,
};
struct stack_info {
enum stack_type type;
unsigned long begin, end;
};
const char *stack_type_name(enum stack_type type);
int get_stack_info(unsigned long sp, struct task_struct *task,
struct stack_info *info, unsigned long *visit_mask);
static inline bool on_stack(struct stack_info *info,
unsigned long addr, size_t len)
{
if (info->type == STACK_TYPE_UNKNOWN)
return false;
if (addr + len < addr)
return false;
return addr >= info->begin && addr + len < info->end;
}
static inline unsigned long get_stack_pointer(struct task_struct *task,
struct pt_regs *regs)
{
if (regs)
return (unsigned long) kernel_stack_pointer(regs);
if (task == current)
return current_stack_pointer();
return (unsigned long) task->thread.ksp;
}
/*
* Stack layout of a C stack frame.
*/
#ifndef __PACK_STACK
struct stack_frame {
unsigned long back_chain;
unsigned long empty1[5];
unsigned long gprs[10];
unsigned int empty2[8];
};
#else
struct stack_frame {
unsigned long empty1[5];
unsigned int empty2[8];
unsigned long gprs[10];
unsigned long back_chain;
};
#endif
#define CALL_ARGS_0() \
register unsigned long r2 asm("2")
#define CALL_ARGS_1(arg1) \
register unsigned long r2 asm("2") = (unsigned long)(arg1)
#define CALL_ARGS_2(arg1, arg2) \
CALL_ARGS_1(arg1); \
register unsigned long r3 asm("3") = (unsigned long)(arg2)
#define CALL_ARGS_3(arg1, arg2, arg3) \
CALL_ARGS_2(arg1, arg2); \
register unsigned long r4 asm("4") = (unsigned long)(arg3)
#define CALL_ARGS_4(arg1, arg2, arg3, arg4) \
CALL_ARGS_3(arg1, arg2, arg3); \
register unsigned long r4 asm("5") = (unsigned long)(arg4)
#define CALL_ARGS_5(arg1, arg2, arg3, arg4, arg5) \
CALL_ARGS_4(arg1, arg2, arg3, arg4); \
register unsigned long r4 asm("6") = (unsigned long)(arg5)
#define CALL_FMT_0 "=&d" (r2) :
#define CALL_FMT_1 "+&d" (r2) :
#define CALL_FMT_2 CALL_FMT_1 "d" (r3),
#define CALL_FMT_3 CALL_FMT_2 "d" (r4),
#define CALL_FMT_4 CALL_FMT_3 "d" (r5),
#define CALL_FMT_5 CALL_FMT_4 "d" (r6),
#define CALL_CLOBBER_5 "0", "1", "14", "cc", "memory"
#define CALL_CLOBBER_4 CALL_CLOBBER_5
#define CALL_CLOBBER_3 CALL_CLOBBER_4, "5"
#define CALL_CLOBBER_2 CALL_CLOBBER_3, "4"
#define CALL_CLOBBER_1 CALL_CLOBBER_2, "3"
#define CALL_CLOBBER_0 CALL_CLOBBER_1
#define CALL_ON_STACK(fn, stack, nr, args...) \
({ \
CALL_ARGS_##nr(args); \
unsigned long prev; \
\
asm volatile( \
" la %[_prev],0(15)\n" \
" la 15,0(%[_stack])\n" \
" stg %[_prev],%[_bc](15)\n" \
" brasl 14,%[_fn]\n" \
" la 15,0(%[_prev])\n" \
: [_prev] "=&a" (prev), CALL_FMT_##nr \
[_stack] "a" (stack), \
[_bc] "i" (offsetof(struct stack_frame, back_chain)), \
[_fn] "X" (fn) : CALL_CLOBBER_##nr); \
r2; \
})
#endif /* _ASM_S390_STACKTRACE_H */

101
arch/s390/include/asm/unwind.h Normal file
View File

@ -0,0 +1,101 @@
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_S390_UNWIND_H
#define _ASM_S390_UNWIND_H
#include <linux/sched.h>
#include <linux/ftrace.h>
#include <asm/ptrace.h>
#include <asm/stacktrace.h>
/*
* To use the stack unwinder it has to be initialized with unwind_start.
* There four combinations for task and regs:
* 1) task==NULL, regs==NULL: the unwind starts for the task that is currently
* running, sp/ip picked up from the CPU registers
* 2) task==NULL, regs!=NULL: the unwind starts from the sp/ip found in
* the struct pt_regs of an interrupt frame for the current task
* 3) task!=NULL, regs==NULL: the unwind starts for an inactive task with
* the sp picked up from task->thread.ksp and the ip picked up from the
* return address stored by __switch_to
* 4) task!=NULL, regs!=NULL: the sp/ip are picked up from the interrupt
* frame 'regs' of a inactive task
* If 'first_frame' is not zero unwind_start skips unwind frames until it
* reaches the specified stack pointer.
* The end of the unwinding is indicated with unwind_done, this can be true
* right after unwind_start, e.g. with first_frame!=0 that can not be found.
* unwind_next_frame skips to the next frame.
* Once the unwind is completed unwind_error() can be used to check if there
* has been a situation where the unwinder could not correctly understand
* the tasks call chain.
*/
struct unwind_state {
struct stack_info stack_info;
unsigned long stack_mask;
struct task_struct *task;
struct pt_regs *regs;
unsigned long sp, ip;
int graph_idx;
bool reliable;
bool error;
};
void __unwind_start(struct unwind_state *state, struct task_struct *task,
struct pt_regs *regs, unsigned long first_frame);
bool unwind_next_frame(struct unwind_state *state);
unsigned long unwind_get_return_address(struct unwind_state *state);
static inline bool unwind_done(struct unwind_state *state)
{
return state->stack_info.type == STACK_TYPE_UNKNOWN;
}
static inline bool unwind_error(struct unwind_state *state)
{
return state->error;
}
static inline void unwind_start(struct unwind_state *state,
struct task_struct *task,
struct pt_regs *regs,
unsigned long sp)
{
sp = sp ? : get_stack_pointer(task, regs);
__unwind_start(state, task, regs, sp);
}
static inline struct pt_regs *unwind_get_entry_regs(struct unwind_state *state)
{
return unwind_done(state) ? NULL : state->regs;
}
#define unwind_for_each_frame(state, task, regs, first_frame) \
for (unwind_start(state, task, regs, first_frame); \
!unwind_done(state); \
unwind_next_frame(state))
static inline void unwind_init(void) {}
static inline void unwind_module_init(struct module *mod, void *orc_ip,
size_t orc_ip_size, void *orc,
size_t orc_size) {}
#ifdef CONFIG_KASAN
/*
* This disables KASAN checking when reading a value from another task's stack,
* since the other task could be running on another CPU and could have poisoned
* the stack in the meantime.
*/
#define READ_ONCE_TASK_STACK(task, x) \
({ \
unsigned long val; \
if (task == current) \
val = READ_ONCE(x); \
else \
val = READ_ONCE_NOCHECK(x); \
val; \
})
#else
#define READ_ONCE_TASK_STACK(task, x) READ_ONCE(x)
#endif
#endif /* _ASM_S390_UNWIND_H */

3
arch/s390/kernel/Makefile
View File

@ -39,6 +39,7 @@ CFLAGS_smp.o := -Wno-nonnull
#
CFLAGS_stacktrace.o += -fno-optimize-sibling-calls
CFLAGS_dumpstack.o += -fno-optimize-sibling-calls
CFLAGS_unwind_bc.o += -fno-optimize-sibling-calls
#
# Pass UTS_MACHINE for user_regset definition
@ -51,7 +52,7 @@ obj-y += debug.o irq.o ipl.o dis.o diag.o vdso.o early_nobss.o
obj-y += sysinfo.o lgr.o os_info.o machine_kexec.o pgm_check.o
obj-y += runtime_instr.o cache.o fpu.o dumpstack.o guarded_storage.o sthyi.o
obj-y += entry.o reipl.o relocate_kernel.o kdebugfs.o alternative.o
obj-y += nospec-branch.o ipl_vmparm.o machine_kexec_reloc.o
obj-y += nospec-branch.o ipl_vmparm.o machine_kexec_reloc.o unwind_bc.o
extra-y += head64.o vmlinux.lds

1
arch/s390/kernel/asm-offsets.c
View File

@ -16,6 +16,7 @@
#include <asm/pgtable.h>
#include <asm/gmap.h>
#include <asm/nmi.h>
#include <asm/stacktrace.h>
int main(void)
{

167
arch/s390/kernel/dumpstack.c
View File

@ -21,95 +21,124 @@
#include <asm/debug.h>
#include <asm/dis.h>
#include <asm/ipl.h>
#include <asm/unwind.h>
/*
* For dump_trace we have tree different stack to consider:
* - the panic stack which is used if the kernel stack has overflown
* - the asynchronous interrupt stack (cpu related)
* - the synchronous kernel stack (process related)
* The stack trace can start at any of the three stacks and can potentially
* touch all of them. The order is: panic stack, async stack, sync stack.
*/
static unsigned long __no_sanitize_address
__dump_trace(dump_trace_func_t func, void *data, unsigned long sp,
unsigned long low, unsigned long high)
const char *stack_type_name(enum stack_type type)
{
struct stack_frame *sf;
struct pt_regs *regs;
while (1) {
if (sp < low || sp > high - sizeof(*sf))
return sp;
sf = (struct stack_frame *) sp;
if (func(data, sf->gprs[8], 0))
return sp;
/* Follow the backchain. */
while (1) {
low = sp;
sp = sf->back_chain;
if (!sp)
break;
if (sp <= low || sp > high - sizeof(*sf))
return sp;
sf = (struct stack_frame *) sp;
if (func(data, sf->gprs[8], 1))
return sp;
}
/* Zero backchain detected, check for interrupt frame. */
sp = (unsigned long) (sf + 1);
if (sp <= low || sp > high - sizeof(*regs))
return sp;
regs = (struct pt_regs *) sp;
if (!user_mode(regs)) {
if (func(data, regs->psw.addr, 1))
return sp;
}
low = sp;
sp = regs->gprs[15];
switch (type) {
case STACK_TYPE_TASK:
return "task";
case STACK_TYPE_IRQ:
return "irq";
case STACK_TYPE_NODAT:
return "nodat";
case STACK_TYPE_RESTART:
return "restart";
default:
return "unknown";
}
}
void dump_trace(dump_trace_func_t func, void *data, struct task_struct *task,
unsigned long sp)
static inline bool in_stack(unsigned long sp, struct stack_info *info,
enum stack_type type, unsigned long low,
unsigned long high)
{
unsigned long frame_size;
if (sp < low || sp >= high)
return false;
info->type = type;
info->begin = low;
info->end = high;
return true;
}
static bool in_task_stack(unsigned long sp, struct task_struct *task,
struct stack_info *info)
{
unsigned long stack;
stack = (unsigned long) task_stack_page(task);
return in_stack(sp, info, STACK_TYPE_TASK, stack, stack + THREAD_SIZE);
}
static bool in_irq_stack(unsigned long sp, struct stack_info *info)
{
unsigned long frame_size, top;
frame_size = STACK_FRAME_OVERHEAD + sizeof(struct pt_regs);
#ifdef CONFIG_CHECK_STACK
sp = __dump_trace(func, data, sp,
S390_lowcore.nodat_stack + frame_size - THREAD_SIZE,
S390_lowcore.nodat_stack + frame_size);
#endif
sp = __dump_trace(func, data, sp,
S390_lowcore.async_stack + frame_size - THREAD_SIZE,
S390_lowcore.async_stack + frame_size);
task = task ?: current;
__dump_trace(func, data, sp,
(unsigned long)task_stack_page(task),
(unsigned long)task_stack_page(task) + THREAD_SIZE);
top = S390_lowcore.async_stack + frame_size;
return in_stack(sp, info, STACK_TYPE_IRQ, top - THREAD_SIZE, top);
}
EXPORT_SYMBOL_GPL(dump_trace);
static int show_address(void *data, unsigned long address, int reliable)
static bool in_nodat_stack(unsigned long sp, struct stack_info *info)
{
if (reliable)
printk(" [<%016lx>] %pSR \n", address, (void *)address);
else
printk("([<%016lx>] %pSR)\n", address, (void *)address);
unsigned long frame_size, top;
frame_size = STACK_FRAME_OVERHEAD + sizeof(struct pt_regs);
top = S390_lowcore.nodat_stack + frame_size;
return in_stack(sp, info, STACK_TYPE_NODAT, top - THREAD_SIZE, top);
}
static bool in_restart_stack(unsigned long sp, struct stack_info *info)
{
unsigned long frame_size, top;
frame_size = STACK_FRAME_OVERHEAD + sizeof(struct pt_regs);
top = S390_lowcore.restart_stack + frame_size;
return in_stack(sp, info, STACK_TYPE_RESTART, top - THREAD_SIZE, top);
}
int get_stack_info(unsigned long sp, struct task_struct *task,
struct stack_info *info, unsigned long *visit_mask)
{
if (!sp)
goto unknown;
task = task ? : current;
/* Check per-task stack */
if (in_task_stack(sp, task, info))
goto recursion_check;
if (task != current)
goto unknown;
/* Check per-cpu stacks */
if (!in_irq_stack(sp, info) &&
!in_nodat_stack(sp, info) &&
!in_restart_stack(sp, info))
goto unknown;
recursion_check:
/*
* Make sure we don't iterate through any given stack more than once.
* If it comes up a second time then there's something wrong going on:
* just break out and report an unknown stack type.
*/
if (*visit_mask & (1UL << info->type)) {
printk_deferred_once(KERN_WARNING
"WARNING: stack recursion on stack type %d\n",
info->type);
goto unknown;
}
*visit_mask |= 1UL << info->type;
return 0;
unknown:
info->type = STACK_TYPE_UNKNOWN;
return -EINVAL;
}
void show_stack(struct task_struct *task, unsigned long *stack)
{
unsigned long sp = (unsigned long) stack;
struct unwind_state state;
if (!sp)
sp = task ? task->thread.ksp : current_stack_pointer();
printk("Call Trace:\n");
dump_trace(show_address, NULL, task, sp);
if (!task)
task = current;
debug_show_held_locks(task);
unwind_for_each_frame(&state, task, NULL, (unsigned long) stack)
printk(state.reliable ? " [<%016lx>] %pSR \n" :
"([<%016lx>] %pSR)\n",
state.ip, (void *) state.ip);
debug_show_held_locks(task ? : current);
}
static void show_last_breaking_event(struct pt_regs *regs)

1
arch/s390/kernel/irq.c
View File

@ -26,6 +26,7 @@
#include <asm/lowcore.h>
#include <asm/irq.h>
#include <asm/hw_irq.h>
#include <asm/stacktrace.h>
#include "entry.h"
DEFINE_PER_CPU_SHARED_ALIGNED(struct irq_stat, irq_stat);

1
arch/s390/kernel/machine_kexec.c
View File

@ -27,6 +27,7 @@
#include <asm/cacheflush.h>
#include <asm/os_info.h>
#include <asm/set_memory.h>
#include <asm/stacktrace.h>
#include <asm/switch_to.h>
#include <asm/nmi.h>

16
arch/s390/kernel/perf_event.c
View File

@ -21,6 +21,7 @@
#include <asm/lowcore.h>
#include <asm/processor.h>
#include <asm/sysinfo.h>
#include <asm/unwind.h>
const char *perf_pmu_name(void)
{
@ -219,20 +220,13 @@ static int __init service_level_perf_register(void)
}
arch_initcall(service_level_perf_register);
static int __perf_callchain_kernel(void *data, unsigned long address, int reliable)
{
struct perf_callchain_entry_ctx *entry = data;
perf_callchain_store(entry, address);
return 0;
}
void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry,
struct pt_regs *regs)
{
if (user_mode(regs))
return;
dump_trace(__perf_callchain_kernel, entry, NULL, regs->gprs[15]);
struct unwind_state state;
unwind_for_each_frame(&state, current, regs, 0)
perf_callchain_store(entry, state.ip);
}
/* Perf definitions for PMU event attributes in sysfs */

1
arch/s390/kernel/process.c
View File

@ -37,6 +37,7 @@
#include <asm/irq.h>
#include <asm/nmi.h>
#include <asm/smp.h>
#include <asm/stacktrace.h>
#include <asm/switch_to.h>
#include <asm/runtime_instr.h>
#include "entry.h"

1
arch/s390/kernel/setup.c
View File

@ -66,6 +66,7 @@
#include <asm/diag.h>
#include <asm/os_info.h>
#include <asm/sclp.h>
#include <asm/stacktrace.h>
#include <asm/sysinfo.h>
#include <asm/numa.h>
#include <asm/alternative.h>

1
arch/s390/kernel/smp.c
View File

@ -53,6 +53,7 @@
#include <asm/sigp.h>
#include <asm/idle.h>
#include <asm/nmi.h>
#include <asm/stacktrace.h>
#include <asm/topology.h>
#include "entry.h"

69
arch/s390/kernel/stacktrace.c
View File

@ -11,40 +11,21 @@
#include <linux/stacktrace.h>
#include <linux/kallsyms.h>
#include <linux/export.h>
static int __save_address(void *data, unsigned long address, int nosched)
{
struct stack_trace *trace = data;
if (nosched && in_sched_functions(address))
return 0;
if (trace->skip > 0) {
trace->skip--;
return 0;
}
if (trace->nr_entries < trace->max_entries) {
trace->entries[trace->nr_entries++] = address;
return 0;
}
return 1;
}
static int save_address(void *data, unsigned long address, int reliable)
{
return __save_address(data, address, 0);
}
static int save_address_nosched(void *data, unsigned long address, int reliable)
{
return __save_address(data, address, 1);
}
#include <asm/stacktrace.h>
#include <asm/unwind.h>
void save_stack_trace(struct stack_trace *trace)
{
unsigned long sp;
struct unwind_state state;
sp = current_stack_pointer();
dump_trace(save_address, trace, NULL, sp);
unwind_for_each_frame(&state, current, NULL, 0) {
if (trace->nr_entries >= trace->max_entries)
break;
if (trace->skip > 0)
trace->skip--;
else
trace->entries[trace->nr_entries++] = state.ip;
}
if (trace->nr_entries < trace->max_entries)
trace->entries[trace->nr_entries++] = ULONG_MAX;
}
@ -52,12 +33,18 @@ EXPORT_SYMBOL_GPL(save_stack_trace);
void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
{
unsigned long sp;
struct unwind_state state;
sp = tsk->thread.ksp;
if (tsk == current)
sp = current_stack_pointer();
dump_trace(save_address_nosched, trace, tsk, sp);
unwind_for_each_frame(&state, tsk, NULL, 0) {
if (trace->nr_entries >= trace->max_entries)
break;
if (in_sched_functions(state.ip))
continue;
if (trace->skip > 0)
trace->skip--;
else
trace->entries[trace->nr_entries++] = state.ip;
}
if (trace->nr_entries < trace->max_entries)
trace->entries[trace->nr_entries++] = ULONG_MAX;
}
@ -65,10 +52,16 @@ EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
{
unsigned long sp;
struct unwind_state state;
sp = kernel_stack_pointer(regs);
dump_trace(save_address, trace, NULL, sp);
unwind_for_each_frame(&state, current, regs, 0) {
if (trace->nr_entries >= trace->max_entries)
break;
if (trace->skip > 0)
trace->skip--;
else
trace->entries[trace->nr_entries++] = state.ip;
}
if (trace->nr_entries < trace->max_entries)
trace->entries[trace->nr_entries++] = ULONG_MAX;
}

155
arch/s390/kernel/unwind_bc.c Normal file
View File

@ -0,0 +1,155 @@
/* SPDX-License-Identifier: GPL-2.0 */
#include <linux/sched.h>
#include <linux/sched/task.h>
#include <linux/sched/task_stack.h>
#include <linux/interrupt.h>
#include <asm/sections.h>
#include <asm/ptrace.h>
#include <asm/bitops.h>
#include <asm/stacktrace.h>
#include <asm/unwind.h>
unsigned long unwind_get_return_address(struct unwind_state *state)
{
if (unwind_done(state))
return 0;
return __kernel_text_address(state->ip) ? state->ip : 0;
}
EXPORT_SYMBOL_GPL(unwind_get_return_address);
static bool outside_of_stack(struct unwind_state *state, unsigned long sp)
{
return (sp <= state->sp) ||
(sp + sizeof(struct stack_frame) > state->stack_info.end);
}
static bool update_stack_info(struct unwind_state *state, unsigned long sp)
{
struct stack_info *info = &state->stack_info;
unsigned long *mask = &state->stack_mask;
/* New stack pointer leaves the current stack */
if (get_stack_info(sp, state->task, info, mask) != 0 ||
!on_stack(info, sp, sizeof(struct stack_frame)))
/* 'sp' does not point to a valid stack */
return false;
return true;
}
bool unwind_next_frame(struct unwind_state *state)
{
struct stack_info *info = &state->stack_info;
struct stack_frame *sf;
struct pt_regs *regs;
unsigned long sp, ip;
bool reliable;
regs = state->regs;
if (unlikely(regs)) {
sp = READ_ONCE_TASK_STACK(state->task, regs->gprs[15]);
if (unlikely(outside_of_stack(state, sp))) {
if (!update_stack_info(state, sp))
goto out_err;
}
sf = (struct stack_frame *) sp;
ip = READ_ONCE_TASK_STACK(state->task, sf->gprs[8]);
reliable = false;
regs = NULL;
} else {
sf = (struct stack_frame *) state->sp;
sp = READ_ONCE_TASK_STACK(state->task, sf->back_chain);
if (likely(sp)) {
/* Non-zero back-chain points to the previous frame */
if (unlikely(outside_of_stack(state, sp))) {
if (!update_stack_info(state, sp))
goto out_err;
}
sf = (struct stack_frame *) sp;
ip = READ_ONCE_TASK_STACK(state->task, sf->gprs[8]);
reliable = true;
} else {
/* No back-chain, look for a pt_regs structure */
sp = state->sp + STACK_FRAME_OVERHEAD;
if (!on_stack(info, sp, sizeof(struct pt_regs)))
goto out_stop;
regs = (struct pt_regs *) sp;
if (user_mode(regs))
goto out_stop;
ip = READ_ONCE_TASK_STACK(state->task, regs->psw.addr);
reliable = true;
}
}
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
/* Decode any ftrace redirection */
if (ip == (unsigned long) return_to_handler)
ip = ftrace_graph_ret_addr(state->task, &state->graph_idx,
ip, NULL);
#endif
/* Update unwind state */
state->sp = sp;
state->ip = ip;
state->regs = regs;
state->reliable = reliable;
return true;
out_err:
state->error = true;
out_stop:
state->stack_info.type = STACK_TYPE_UNKNOWN;
return false;
}
EXPORT_SYMBOL_GPL(unwind_next_frame);
void __unwind_start(struct unwind_state *state, struct task_struct *task,
struct pt_regs *regs, unsigned long sp)
{
struct stack_info *info = &state->stack_info;
unsigned long *mask = &state->stack_mask;
struct stack_frame *sf;
unsigned long ip;
bool reliable;
memset(state, 0, sizeof(*state));
state->task = task;
state->regs = regs;
/* Don't even attempt to start from user mode regs: */
if (regs && user_mode(regs)) {
info->type = STACK_TYPE_UNKNOWN;
return;
}
/* Get current stack pointer and initialize stack info */
if (get_stack_info(sp, task, info, mask) != 0 ||
!on_stack(info, sp, sizeof(struct stack_frame))) {
/* Something is wrong with the stack pointer */
info->type = STACK_TYPE_UNKNOWN;
state->error = true;
return;
}
/* Get the instruction pointer from pt_regs or the stack frame */
if (regs) {
ip = READ_ONCE_TASK_STACK(state->task, regs->psw.addr);
reliable = true;
} else {
sf = (struct stack_frame *) sp;
ip = READ_ONCE_TASK_STACK(state->task, sf->gprs[8]);
reliable = false;
}
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
/* Decode any ftrace redirection */
if (ip == (unsigned long) return_to_handler)
ip = ftrace_graph_ret_addr(state->task, &state->graph_idx,
ip, NULL);
#endif
/* Update unwind state */
state->sp = sp;
state->ip = ip;
state->reliable = reliable;
}
EXPORT_SYMBOL_GPL(__unwind_start);

1
arch/s390/mm/maccess.c
View File

@ -16,6 +16,7 @@
#include <linux/cpu.h>
#include <asm/ctl_reg.h>
#include <asm/io.h>
#include <asm/stacktrace.h>
static notrace long s390_kernel_write_odd(void *dst, const void *src, size_t size)
{

22
arch/s390/oprofile/init.c
View File

@ -13,23 +13,17 @@
#include <linux/oprofile.h>
#include <linux/init.h>
#include <asm/processor.h>
static int __s390_backtrace(void *data, unsigned long address, int reliable)
{
unsigned int *depth = data;
if (*depth == 0)
return 1;
(*depth)--;
oprofile_add_trace(address);
return 0;
}
#include <asm/unwind.h>
static void s390_backtrace(struct pt_regs *regs, unsigned int depth)
{
if (user_mode(regs))
return;
dump_trace(__s390_backtrace, &depth, NULL, regs->gprs[15]);
struct unwind_state state;
unwind_for_each_frame(&state, current, regs, 0) {
if (depth-- == 0)
break;
oprofile_add_trace(state.ip);
}
}
int __init oprofile_arch_init(struct oprofile_operations *ops)