Techwizz/kernel-fxtec-pro1x
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

Merge branch 'arm64/exception-stack' of git://git.kernel.org/pub/scm/linux/kernel/git/mark/linux into for-next/core

Browse source 
* 'arm64/exception-stack' of git://git.kernel.org/pub/scm/linux/kernel/git/mark/linux:
  arm64: unwind: remove sp from struct stackframe
  arm64: unwind: reference pt_regs via embedded stack frame
  arm64: unwind: disregard frame.sp when validating frame pointer
  arm64: unwind: avoid percpu indirection for irq stack
  arm64: move non-entry code out of .entry.text
  arm64: consistently use bl for C exception entry
  arm64: Add ASM_BUG()
This commit is contained in:
Catalin Marinas 2017-08-09 15:37:49 +01:00
commit 0553896787
17 changed files with 176 additions and 198 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

54
arch/arm64/include/asm/asm-bug.h Normal file
View file

@ -0,0 +1,54 @@
#ifndef __ASM_ASM_BUG_H
/*
* Copyright (C) 2017 ARM Limited
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#define __ASM_ASM_BUG_H
#include <asm/brk-imm.h>
#ifdef CONFIG_DEBUG_BUGVERBOSE
#define _BUGVERBOSE_LOCATION(file, line) __BUGVERBOSE_LOCATION(file, line)
#define __BUGVERBOSE_LOCATION(file, line) \
.pushsection .rodata.str,"aMS",@progbits,1; \
2: .string file; \
.popsection; \
\
.long 2b - 0b; \
.short line;
#else
#define _BUGVERBOSE_LOCATION(file, line)
#endif
#ifdef CONFIG_GENERIC_BUG
#define __BUG_ENTRY(flags) \
.pushsection __bug_table,"aw"; \
.align 2; \
0: .long 1f - 0b; \
_BUGVERBOSE_LOCATION(__FILE__, __LINE__) \
.short flags; \
.popsection; \
1:
#else
#define __BUG_ENTRY(flags)
#endif
#define ASM_BUG_FLAGS(flags) \
__BUG_ENTRY(flags) \
brk BUG_BRK_IMM
#define ASM_BUG() ASM_BUG_FLAGS(0)
#endif /* __ASM_ASM_BUG_H */

11
arch/arm64/include/asm/assembler.h
View file

@ -409,6 +409,17 @@ alternative_endif
.size __pi_##x, . - x; \
ENDPROC(x)
/*
* Annotate a function as being unsuitable for kprobes.
*/
#ifdef CONFIG_KPROBES
#define NOKPROBE(x) \
.pushsection "_kprobe_blacklist", "aw"; \
.quad x; \
.popsection;
#else
#define NOKPROBE(x)
#endif
/*
* Emit a 64-bit absolute little endian symbol reference in a way that
* ensures that it will be resolved at build time, even when building a

35
arch/arm64/include/asm/bug.h
View file

@ -18,41 +18,12 @@
#ifndef _ARCH_ARM64_ASM_BUG_H
#define _ARCH_ARM64_ASM_BUG_H
#include <asm/brk-imm.h>
#include <linux/stringify.h>
#ifdef CONFIG_DEBUG_BUGVERBOSE
#define _BUGVERBOSE_LOCATION(file, line) __BUGVERBOSE_LOCATION(file, line)
#define __BUGVERBOSE_LOCATION(file, line) \
".pushsection .rodata.str,\"aMS\",@progbits,1\n" \
"2: .string \"" file "\"\n\t" \
".popsection\n\t" \
\
".long 2b - 0b\n\t" \
".short " #line "\n\t"
#else
#define _BUGVERBOSE_LOCATION(file, line)
#endif
#ifdef CONFIG_GENERIC_BUG
#define __BUG_ENTRY(flags) \
".pushsection __bug_table,\"aw\"\n\t" \
".align 2\n\t" \
"0: .long 1f - 0b\n\t" \
_BUGVERBOSE_LOCATION(__FILE__, __LINE__) \
".short " #flags "\n\t" \
".popsection\n" \
"1: "
#else
#define __BUG_ENTRY(flags) ""
#endif
#include <asm/asm-bug.h>
#define __BUG_FLAGS(flags) \
asm volatile ( \
__BUG_ENTRY(flags) \
"brk %[imm]" :: [imm] "i" (BUG_BRK_IMM) \
);
asm volatile (__stringify(ASM_BUG_FLAGS(flags)));
#define BUG() do { \
__BUG_FLAGS(0); \

39
arch/arm64/include/asm/irq.h
View file

@ -7,6 +7,7 @@
#ifndef __ASSEMBLER__
#include <linux/percpu.h>
#include <linux/sched/task_stack.h>
#include <asm-generic/irq.h>
#include <asm/thread_info.h>
@ -15,31 +16,6 @@ struct pt_regs;
DECLARE_PER_CPU(unsigned long [IRQ_STACK_SIZE/sizeof(long)], irq_stack);
/*
* The highest address on the stack, and the first to be used. Used to
* find the dummy-stack frame put down by el?_irq() in entry.S, which
* is structured as follows:
*
* ------------
* | | <- irq_stack_ptr
* top ------------
* | x19 | <- irq_stack_ptr - 0x08
* ------------
* | x29 | <- irq_stack_ptr - 0x10
* ------------
*
* where x19 holds a copy of the task stack pointer where the struct pt_regs
* from kernel_entry can be found.
*
*/
#define IRQ_STACK_PTR(cpu) ((unsigned long)per_cpu(irq_stack, cpu) + IRQ_STACK_START_SP)
/*
* The offset from irq_stack_ptr where entry.S will store the original
* stack pointer. Used by unwind_frame() and dump_backtrace().
*/
#define IRQ_STACK_TO_TASK_STACK(ptr) (*((unsigned long *)((ptr) - 0x08)))
extern void set_handle_irq(void (*handle_irq)(struct pt_regs *));
static inline int nr_legacy_irqs(void)
@ -47,14 +23,21 @@ static inline int nr_legacy_irqs(void)
return 0;
}
static inline bool on_irq_stack(unsigned long sp, int cpu)
static inline bool on_irq_stack(unsigned long sp)
{
/* variable names the same as kernel/stacktrace.c */
unsigned long low = (unsigned long)per_cpu(irq_stack, cpu);
unsigned long low = (unsigned long)raw_cpu_ptr(irq_stack);
unsigned long high = low + IRQ_STACK_START_SP;
return (low <= sp && sp <= high);
}
static inline bool on_task_stack(struct task_struct *tsk, unsigned long sp)
{
unsigned long low = (unsigned long)task_stack_page(tsk);
unsigned long high = low + THREAD_SIZE;
return (low <= sp && sp < high);
}
#endif /* !__ASSEMBLER__ */
#endif

1
arch/arm64/include/asm/ptrace.h
View file

@ -137,6 +137,7 @@ struct pt_regs {
u64 orig_addr_limit;
u64 unused; // maintain 16 byte alignment
u64 stackframe[2];
};
static inline bool in_syscall(struct pt_regs const *regs)

1
arch/arm64/include/asm/stacktrace.h
View file

@ -20,7 +20,6 @@ struct task_struct;
struct stackframe {
unsigned long fp;
unsigned long sp;
unsigned long pc;
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
unsigned int graph;

5
arch/arm64/include/asm/traps.h
View file

@ -60,4 +60,9 @@ static inline int in_exception_text(unsigned long ptr)
return in ? : __in_irqentry_text(ptr);
}
static inline int in_entry_text(unsigned long ptr)
{
return ptr >= (unsigned long)&__entry_text_start &&
ptr < (unsigned long)&__entry_text_end;
}
#endif

1
arch/arm64/kernel/asm-offsets.c
View file

@ -75,6 +75,7 @@ int main(void)
DEFINE(S_ORIG_X0, offsetof(struct pt_regs, orig_x0));
DEFINE(S_SYSCALLNO, offsetof(struct pt_regs, syscallno));
DEFINE(S_ORIG_ADDR_LIMIT, offsetof(struct pt_regs, orig_addr_limit));
DEFINE(S_STACKFRAME, offsetof(struct pt_regs, stackframe));
DEFINE(S_FRAME_SIZE, sizeof(struct pt_regs));
BLANK();
DEFINE(MM_CONTEXT_ID, offsetof(struct mm_struct, context.id.counter));

122
arch/arm64/kernel/entry.S
View file

@ -111,6 +111,18 @@
mrs x23, spsr_el1
stp lr, x21, [sp, #S_LR]
/*
* In order to be able to dump the contents of struct pt_regs at the
* time the exception was taken (in case we attempt to walk the call
* stack later), chain it together with the stack frames.
*/
.if \el == 0
stp xzr, xzr, [sp, #S_STACKFRAME]
.else
stp x29, x22, [sp, #S_STACKFRAME]
.endif
add x29, sp, #S_STACKFRAME
#ifdef CONFIG_ARM64_SW_TTBR0_PAN
/*
* Set the TTBR0 PAN bit in SPSR. When the exception is taken from
@ -263,14 +275,6 @@ alternative_else_nop_endif
/* switch to the irq stack */
mov sp, x26
/*
* Add a dummy stack frame, this non-standard format is fixed up
* by unwind_frame()
*/
stp x29, x19, [sp, #-16]!
mov x29, sp
9998:
.endm
@ -350,7 +354,8 @@ END(vectors)
mov x0, sp
mov x1, #\reason
mrs x2, esr_el1
b bad_mode
bl bad_mode
ASM_BUG()
.endm
el0_sync_invalid:
@ -447,14 +452,16 @@ el1_sp_pc:
mrs x0, far_el1
enable_dbg
mov x2, sp
b do_sp_pc_abort
bl do_sp_pc_abort
ASM_BUG()
el1_undef:
/*
* Undefined instruction
*/
enable_dbg
mov x0, sp
b do_undefinstr
bl do_undefinstr
ASM_BUG()
el1_dbg:
/*
* Debug exception handling
@ -472,7 +479,8 @@ el1_inv:
mov x0, sp
mov x2, x1
mov x1, #BAD_SYNC
b bad_mode
bl bad_mode
ASM_BUG()
ENDPROC(el1_sync)
.align 6
@ -705,38 +713,6 @@ el0_irq_naked:
b ret_to_user
ENDPROC(el0_irq)
/*
* Register switch for AArch64. The callee-saved registers need to be saved
* and restored. On entry:
* x0 = previous task_struct (must be preserved across the switch)
* x1 = next task_struct
* Previous and next are guaranteed not to be the same.
*
*/
ENTRY(cpu_switch_to)
mov x10, #THREAD_CPU_CONTEXT
add x8, x0, x10
mov x9, sp
stp x19, x20, [x8], #16 // store callee-saved registers
stp x21, x22, [x8], #16
stp x23, x24, [x8], #16
stp x25, x26, [x8], #16
stp x27, x28, [x8], #16
stp x29, x9, [x8], #16
str lr, [x8]
add x8, x1, x10
ldp x19, x20, [x8], #16 // restore callee-saved registers
ldp x21, x22, [x8], #16
ldp x23, x24, [x8], #16
ldp x25, x26, [x8], #16
ldp x27, x28, [x8], #16
ldp x29, x9, [x8], #16
ldr lr, [x8]
mov sp, x9
msr sp_el0, x1
ret
ENDPROC(cpu_switch_to)
/*
* This is the fast syscall return path. We do as little as possible here,
* and this includes saving x0 back into the kernel stack.
@ -779,18 +755,6 @@ finish_ret_to_user:
kernel_exit 0
ENDPROC(ret_to_user)
/*
* This is how we return from a fork.
*/
ENTRY(ret_from_fork)
bl schedule_tail
cbz x19, 1f // not a kernel thread
mov x0, x20
blr x19
1: get_thread_info tsk
b ret_to_user
ENDPROC(ret_from_fork)
/*
* SVC handler.
*/
@ -863,3 +827,49 @@ ENTRY(sys_rt_sigreturn_wrapper)
mov x0, sp
b sys_rt_sigreturn
ENDPROC(sys_rt_sigreturn_wrapper)
/*
* Register switch for AArch64. The callee-saved registers need to be saved
* and restored. On entry:
* x0 = previous task_struct (must be preserved across the switch)
* x1 = next task_struct
* Previous and next are guaranteed not to be the same.
*
*/
ENTRY(cpu_switch_to)
mov x10, #THREAD_CPU_CONTEXT
add x8, x0, x10
mov x9, sp
stp x19, x20, [x8], #16 // store callee-saved registers
stp x21, x22, [x8], #16
stp x23, x24, [x8], #16
stp x25, x26, [x8], #16
stp x27, x28, [x8], #16
stp x29, x9, [x8], #16
str lr, [x8]
add x8, x1, x10
ldp x19, x20, [x8], #16 // restore callee-saved registers
ldp x21, x22, [x8], #16
ldp x23, x24, [x8], #16
ldp x25, x26, [x8], #16
ldp x27, x28, [x8], #16
ldp x29, x9, [x8], #16
ldr lr, [x8]
mov sp, x9
msr sp_el0, x1
ret
ENDPROC(cpu_switch_to)
NOKPROBE(cpu_switch_to)
/*
* This is how we return from a fork.
*/
ENTRY(ret_from_fork)
bl schedule_tail
cbz x19, 1f // not a kernel thread
mov x0, x20
blr x19
1: get_thread_info tsk
b ret_to_user
ENDPROC(ret_from_fork)
NOKPROBE(ret_from_fork)

4
arch/arm64/kernel/head.S
View file

@ -362,6 +362,9 @@ __primary_switched:
ret // to __primary_switch()
0:
#endif
add sp, sp, #16
mov x29, #0
mov x30, #0
b start_kernel
ENDPROC(__primary_switched)
@ -617,6 +620,7 @@ __secondary_switched:
ldr x2, [x0, #CPU_BOOT_TASK]
msr sp_el0, x2
mov x29, #0
mov x30, #0
b secondary_start_kernel
ENDPROC(__secondary_switched)

1
arch/arm64/kernel/perf_callchain.c
View file

@ -162,7 +162,6 @@ void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry,
}
frame.fp = regs->regs[29];
frame.sp = regs->sp;
frame.pc = regs->pc;
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
frame.graph = current->curr_ret_stack;

5
arch/arm64/kernel/process.c
View file

@ -382,15 +382,12 @@ unsigned long get_wchan(struct task_struct *p)
return 0;
frame.fp = thread_saved_fp(p);
frame.sp = thread_saved_sp(p);
frame.pc = thread_saved_pc(p);
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
frame.graph = p->curr_ret_stack;
#endif
do {
if (frame.sp < stack_page ||
frame.sp >= stack_page + THREAD_SIZE ||
unwind_frame(p, &frame))
if (unwind_frame(p, &frame))
goto out;
if (!in_sched_functions(frame.pc)) {
ret = frame.pc;

2
arch/arm64/kernel/ptrace.c
View file

@ -127,7 +127,7 @@ static bool regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
{
return ((addr & ~(THREAD_SIZE - 1)) ==
(kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1))) ||
on_irq_stack(addr, raw_smp_processor_id());
on_irq_stack(addr);
}
/**

1
arch/arm64/kernel/return_address.c
View file

@ -42,7 +42,6 @@ void *return_address(unsigned int level)
data.addr = NULL;
frame.fp = (unsigned long)__builtin_frame_address(0);
frame.sp = current_stack_pointer;
frame.pc = (unsigned long)return_address; /* dummy */
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
frame.graph = current->curr_ret_stack;

57
arch/arm64/kernel/stacktrace.c
View file

@ -42,9 +42,10 @@
*/
int notrace unwind_frame(struct task_struct *tsk, struct stackframe *frame)
{
unsigned long high, low;
unsigned long fp = frame->fp;
unsigned long irq_stack_ptr;
if (fp & 0xf)
return -EINVAL;
if (!tsk)
tsk = current;
@ -53,22 +54,10 @@ int notrace unwind_frame(struct task_struct *tsk, struct stackframe *frame)
* Switching between stacks is valid when tracing current and in
* non-preemptible context.
*/
if (tsk == current && !preemptible())
irq_stack_ptr = IRQ_STACK_PTR(smp_processor_id());
else
irq_stack_ptr = 0;
low = frame->sp;
/* irq stacks are not THREAD_SIZE aligned */
if (on_irq_stack(frame->sp, raw_smp_processor_id()))
high = irq_stack_ptr;
else
high = ALIGN(low, THREAD_SIZE) - 0x20;
if (fp < low || fp > high || fp & 0xf)
if (!(tsk == current && !preemptible() && on_irq_stack(fp)) &&
!on_task_stack(tsk, fp))
return -EINVAL;
frame->sp = fp + 0x10;
frame->fp = READ_ONCE_NOCHECK(*(unsigned long *)(fp));
frame->pc = READ_ONCE_NOCHECK(*(unsigned long *)(fp + 8));
@ -86,34 +75,13 @@ int notrace unwind_frame(struct task_struct *tsk, struct stackframe *frame)
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
/*
* Check whether we are going to walk through from interrupt stack
* to task stack.
* If we reach the end of the stack - and its an interrupt stack,
* unpack the dummy frame to find the original elr.
*
* Check the frame->fp we read from the bottom of the irq_stack,
* and the original task stack pointer are both in current->stack.
* Frames created upon entry from EL0 have NULL FP and PC values, so
* don't bother reporting these. Frames created by __noreturn functions
* might have a valid FP even if PC is bogus, so only terminate where
* both are NULL.
*/
if (frame->sp == irq_stack_ptr) {
struct pt_regs *irq_args;
unsigned long orig_sp = IRQ_STACK_TO_TASK_STACK(irq_stack_ptr);
if (object_is_on_stack((void *)orig_sp) &&
object_is_on_stack((void *)frame->fp)) {
frame->sp = orig_sp;
/* orig_sp is the saved pt_regs, find the elr */
irq_args = (struct pt_regs *)orig_sp;
frame->pc = irq_args->pc;
} else {
/*
* This frame has a non-standard format, and we
* didn't fix it, because the data looked wrong.
* Refuse to output this frame.
*/
return -EINVAL;
}
}
if (!frame->fp && !frame->pc)
return -EINVAL;
return 0;
}
@ -167,7 +135,6 @@ void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
data.no_sched_functions = 0;
frame.fp = regs->regs[29];
frame.sp = regs->sp;
frame.pc = regs->pc;
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
frame.graph = current->curr_ret_stack;
@ -192,12 +159,10 @@ void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
if (tsk != current) {
data.no_sched_functions = 1;
frame.fp = thread_saved_fp(tsk);
frame.sp = thread_saved_sp(tsk);
frame.pc = thread_saved_pc(tsk);
} else {
data.no_sched_functions = 0;
frame.fp = (unsigned long)__builtin_frame_address(0);
frame.sp = current_stack_pointer;
frame.pc = (unsigned long)save_stack_trace_tsk;
}
#ifdef CONFIG_FUNCTION_GRAPH_TRACER

1
arch/arm64/kernel/time.c
View file

@ -50,7 +50,6 @@ unsigned long profile_pc(struct pt_regs *regs)
return regs->pc;
frame.fp = regs->regs[29];
frame.sp = regs->sp;
frame.pc = regs->pc;
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
frame.graph = -1; /* no task info */

34
arch/arm64/kernel/traps.c
View file

@ -143,7 +143,6 @@ static void dump_instr(const char *lvl, struct pt_regs *regs)
void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
{
struct stackframe frame;
unsigned long irq_stack_ptr;
int skip;
pr_debug("%s(regs = %p tsk = %p)\n", __func__, regs, tsk);
@ -154,25 +153,14 @@ void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
if (!try_get_task_stack(tsk))
return;
/*
* Switching between stacks is valid when tracing current and in
* non-preemptible context.
*/
if (tsk == current && !preemptible())
irq_stack_ptr = IRQ_STACK_PTR(smp_processor_id());
else
irq_stack_ptr = 0;
if (tsk == current) {
frame.fp = (unsigned long)__builtin_frame_address(0);
frame.sp = current_stack_pointer;
frame.pc = (unsigned long)dump_backtrace;
} else {
/*
* task blocked in __switch_to
*/
frame.fp = thread_saved_fp(tsk);
frame.sp = thread_saved_sp(tsk);
frame.pc = thread_saved_pc(tsk);
}
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
@ -182,13 +170,12 @@ void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
skip = !!regs;
printk("Call trace:\n");
while (1) {
unsigned long where = frame.pc;
unsigned long stack;
int ret;
/* skip until specified stack frame */
if (!skip) {
dump_backtrace_entry(where);
dump_backtrace_entry(frame.pc);
} else if (frame.fp == regs->regs[29]) {
skip = 0;
/*
@ -203,20 +190,13 @@ void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
ret = unwind_frame(tsk, &frame);
if (ret < 0)
break;
stack = frame.sp;
if (in_exception_text(where)) {
/*
* If we switched to the irq_stack before calling this
* exception handler, then the pt_regs will be on the
* task stack. The easiest way to tell is if the large
* pt_regs would overlap with the end of the irq_stack.
*/
if (stack < irq_stack_ptr &&
(stack + sizeof(struct pt_regs)) > irq_stack_ptr)
stack = IRQ_STACK_TO_TASK_STACK(irq_stack_ptr);
if (in_entry_text(frame.pc)) {
stack = frame.fp - offsetof(struct pt_regs, stackframe);
dump_mem("", "Exception stack", stack,
stack + sizeof(struct pt_regs));
if (on_task_stack(tsk, stack) ||
(tsk == current && !preemptible() && on_irq_stack(stack)))
dump_mem("", "Exception stack", stack,
stack + sizeof(struct pt_regs));
}
}