[PATCH 07/13] csky: Optimize the trap processing flow
From: guoren
Date: Fri Jul 31 2020 - 21:15:20 EST
From: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>
- Seperate different trap functions
- Add trap_no()
- Remove panic code print
- Redesign die_if_kerenl to die with riscv's
- Print exact trap info for app segment fault
[ 17.389321] gzip[126]: unhandled signal 11 code 0x3 at 0x0007835a in busybox[8000+d4000]
[ 17.393882]
[ 17.393882] CURRENT PROCESS:
[ 17.393882]
[ 17.394309] COMM=gzip PID=126
[ 17.394513] TEXT=00008000-000db2e4 DATA=000dcf14-000dd1ad BSS=000dd1ad-000ff000
[ 17.395499] USER-STACK=7f888e50 KERNEL-STACK=bf130300
[ 17.395499]
[ 17.396801] PC: 0x0007835a (0x7835a)
[ 17.397048] LR: 0x000058b4 (0x58b4)
[ 17.397285] SP: 0xbe519f68
[ 17.397555] orig_a0: 0x00002852
[ 17.397886] PSR: 0x00020341
[ 17.398356] a0: 0x00002852 a1: 0x000f2f5a a2: 0x0000d7ae a3: 0x0000005d
[ 17.399289] r4: 0x000de150 r5: 0x00000002 r6: 0x00000102 r7: 0x00007efa
[ 17.399800] r8: 0x7f888bc4 r9: 0x00000001 r10: 0x000002eb r11: 0x0000aac1
[ 17.400166] r12: 0x00002ef2 r13: 0x00000007 r15: 0x000058b4
[ 17.400531] r16: 0x0000004c r17: 0x00000031 r18: 0x000f5816 r19: 0x000e8068
[ 17.401006] r20: 0x000f5818 r21: 0x000e8068 r22: 0x000f5918 r23: 0x90000000
[ 17.401721] r24: 0x00000031 r25: 0x000000c8 r26: 0x00000000 r27: 0x00000000
[ 17.402199] r28: 0x2ac2a000 r29: 0x00000000 r30: 0x00000000 tls: 0x2aadbaa8
[ 17.402686] hi: 0x00120340 lo: 0x7f888bec
/etc/init.ci/ntfs3g_run: line 61: 126 Segmentation fault gzip -c -9 /mnt/test.bin > /mnt/test_bin.gz
Signed-off-by: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
---
arch/csky/include/asm/bug.h | 3 +-
arch/csky/include/asm/ptrace.h | 1 +
arch/csky/kernel/ptrace.c | 29 +-----
arch/csky/kernel/traps.c | 223 +++++++++++++++++++++++++++--------------
arch/csky/mm/fault.c | 10 +-
5 files changed, 157 insertions(+), 109 deletions(-)
diff --git a/arch/csky/include/asm/bug.h b/arch/csky/include/asm/bug.h
index bd7b323..33ebd16 100644
--- a/arch/csky/include/asm/bug.h
+++ b/arch/csky/include/asm/bug.h
@@ -20,7 +20,8 @@ do { \
struct pt_regs;
-void die_if_kernel(char *str, struct pt_regs *regs, int nr);
+void die(struct pt_regs *regs, const char *str);
void show_regs(struct pt_regs *regs);
+void show_code(struct pt_regs *regs);
#endif /* __ASM_CSKY_BUG_H */
diff --git a/arch/csky/include/asm/ptrace.h b/arch/csky/include/asm/ptrace.h
index 82da5e0..91ceb1b 100644
--- a/arch/csky/include/asm/ptrace.h
+++ b/arch/csky/include/asm/ptrace.h
@@ -24,6 +24,7 @@
#define user_mode(regs) (!((regs)->sr & PS_S))
#define instruction_pointer(regs) ((regs)->pc)
#define profile_pc(regs) instruction_pointer(regs)
+#define trap_no(regs) ((regs->sr >> 16) & 0xff)
static inline void instruction_pointer_set(struct pt_regs *regs,
unsigned long val)
diff --git a/arch/csky/kernel/ptrace.c b/arch/csky/kernel/ptrace.c
index 0de10f7..b06612c 100644
--- a/arch/csky/kernel/ptrace.c
+++ b/arch/csky/kernel/ptrace.c
@@ -347,13 +347,8 @@ asmlinkage void syscall_trace_exit(struct pt_regs *regs)
trace_sys_exit(regs, syscall_get_return_value(current, regs));
}
-extern void show_stack(struct task_struct *task, unsigned long *stack, const char *loglvl);
void show_regs(struct pt_regs *fp)
{
- unsigned long *sp;
- unsigned char *tp;
- int i;
-
pr_info("\nCURRENT PROCESS:\n\n");
pr_info("COMM=%s PID=%d\n", current->comm, current->pid);
@@ -400,29 +395,9 @@ void show_regs(struct pt_regs *fp)
fp->regs[0], fp->regs[1], fp->regs[2], fp->regs[3]);
pr_info("r10: 0x%08lx r11: 0x%08lx r12: 0x%08lx r13: 0x%08lx\n",
fp->regs[4], fp->regs[5], fp->regs[6], fp->regs[7]);
- pr_info("r14: 0x%08lx r1: 0x%08lx r15: 0x%08lx\n",
- fp->regs[8], fp->regs[9], fp->lr);
+ pr_info("r14: 0x%08lx r1: 0x%08lx\n",
+ fp->regs[8], fp->regs[9]);
#endif
- pr_info("\nCODE:");
- tp = ((unsigned char *) fp->pc) - 0x20;
- tp += ((int)tp % 4) ? 2 : 0;
- for (sp = (unsigned long *) tp, i = 0; (i < 0x40); i += 4) {
- if ((i % 0x10) == 0)
- pr_cont("\n%08x: ", (int) (tp + i));
- pr_cont("%08x ", (int) *sp++);
- }
- pr_cont("\n");
-
- pr_info("\nKERNEL STACK:");
- tp = ((unsigned char *) fp) - 0x40;
- for (sp = (unsigned long *) tp, i = 0; (i < 0xc0); i += 4) {
- if ((i % 0x10) == 0)
- pr_cont("\n%08x: ", (int) (tp + i));
- pr_cont("%08x ", (int) *sp++);
- }
- pr_cont("\n");
-
- show_stack(NULL, (unsigned long *)fp->regs[4], KERN_INFO);
return;
}
diff --git a/arch/csky/kernel/traps.c b/arch/csky/kernel/traps.c
index fcc3a69..959a917 100644
--- a/arch/csky/kernel/traps.c
+++ b/arch/csky/kernel/traps.c
@@ -15,6 +15,8 @@
#include <linux/rtc.h>
#include <linux/uaccess.h>
#include <linux/kprobes.h>
+#include <linux/kdebug.h>
+#include <linux/sched/debug.h>
#include <asm/setup.h>
#include <asm/traps.h>
@@ -27,6 +29,8 @@
#include <abi/fpu.h>
#endif
+int show_unhandled_signals = 1;
+
/* Defined in entry.S */
asmlinkage void csky_trap(void);
@@ -77,117 +81,184 @@ void __init trap_init(void)
#endif
}
-void die_if_kernel(char *str, struct pt_regs *regs, int nr)
+static DEFINE_SPINLOCK(die_lock);
+
+void die(struct pt_regs *regs, const char *str)
{
- if (user_mode(regs))
- return;
+ static int die_counter;
+ int ret;
+ oops_enter();
+
+ spin_lock_irq(&die_lock);
console_verbose();
- pr_err("%s: %08x\n", str, nr);
+ bust_spinlocks(1);
+
+ pr_emerg("%s [#%d]\n", str, ++die_counter);
+ print_modules();
show_regs(regs);
+ show_stack(current, (unsigned long *)regs->regs[4], KERN_INFO);
+
+ ret = notify_die(DIE_OOPS, str, regs, 0, trap_no(regs), SIGSEGV);
+
+ bust_spinlocks(0);
add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
- do_exit(SIGSEGV);
+ spin_unlock_irq(&die_lock);
+ oops_exit();
+
+ if (in_interrupt())
+ panic("Fatal exception in interrupt");
+ if (panic_on_oops)
+ panic("Fatal exception");
+ if (ret != NOTIFY_STOP)
+ do_exit(SIGSEGV);
}
-void buserr(struct pt_regs *regs)
+void do_trap(struct pt_regs *regs, int signo, int code, unsigned long addr)
{
-#ifdef CONFIG_CPU_CK810
- static unsigned long prev_pc;
+ struct task_struct *tsk = current;
- if ((regs->pc == prev_pc) && prev_pc != 0) {
- prev_pc = 0;
- } else {
- prev_pc = regs->pc;
- return;
+ if (show_unhandled_signals && unhandled_signal(tsk, signo)
+ && printk_ratelimit()) {
+ pr_info("%s[%d]: unhandled signal %d code 0x%x at 0x%08lx",
+ tsk->comm, task_pid_nr(tsk), signo, code, addr);
+ print_vma_addr(KERN_CONT " in ", instruction_pointer(regs));
+ pr_cont("\n");
+ show_regs(regs);
}
-#endif
- die_if_kernel("Kernel mode BUS error", regs, 0);
+ force_sig_fault(signo, code, (void __user *)addr);
+}
- pr_err("User mode Bus Error\n");
- show_regs(regs);
+static void do_trap_error(struct pt_regs *regs, int signo, int code,
+ unsigned long addr, const char *str)
+{
+ current->thread.trap_no = trap_no(regs);
- force_sig_fault(SIGSEGV, 0, (void __user *)regs->pc);
+ if (user_mode(regs)) {
+ do_trap(regs, signo, code, addr);
+ } else {
+ if (!fixup_exception(regs))
+ die(regs, str);
+ }
}
-asmlinkage void trap_c(struct pt_regs *regs)
-{
- int sig;
- unsigned long vector;
- siginfo_t info;
- struct task_struct *tsk = current;
+#define DO_ERROR_INFO(name, signo, code, str) \
+asmlinkage __visible void name(struct pt_regs *regs) \
+{ \
+ do_trap_error(regs, signo, code, regs->pc, "Oops - " str); \
+}
- vector = (regs->sr >> 16) & 0xff;
+DO_ERROR_INFO(do_trap_unknown,
+ SIGILL, ILL_ILLTRP, "unknown exception");
+DO_ERROR_INFO(do_trap_zdiv,
+ SIGFPE, FPE_INTDIV, "error zero div exception");
+DO_ERROR_INFO(do_trap_buserr,
+ SIGSEGV, ILL_ILLADR, "error bus error exception");
- switch (vector) {
- case VEC_ZERODIV:
- die_if_kernel("Kernel mode ZERO DIV", regs, vector);
- sig = SIGFPE;
- break;
- /* ptrace */
- case VEC_TRACE:
+asmlinkage void do_trap_misaligned(struct pt_regs *regs)
+{
+#ifdef CONFIG_CPU_NEED_SOFTALIGN
+ csky_alignment(regs);
+#else
+ current->thread.trap_no = trap_no(regs);
+ do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->pc,
+ "Oops - load/store address misaligned");
+#endif
+}
+
+asmlinkage void do_trap_bkpt(struct pt_regs *regs)
+{
#ifdef CONFIG_KPROBES
- if (kprobe_single_step_handler(regs))
- return;
+ if (kprobe_single_step_handler(regs))
+ return;
#endif
#ifdef CONFIG_UPROBES
- if (uprobe_single_step_handler(regs))
- return;
+ if (uprobe_single_step_handler(regs))
+ return;
#endif
- info.si_code = TRAP_TRACE;
- sig = SIGTRAP;
- break;
- case VEC_ILLEGAL:
- tsk->thread.trap_no = vector;
+ if (user_mode(regs)) {
+ send_sig(SIGTRAP, current, 0);
+ return;
+ }
+
+ do_trap_error(regs, SIGILL, ILL_ILLTRP, regs->pc,
+ "Oops - illegal trap exception");
+}
+
+asmlinkage void do_trap_illinsn(struct pt_regs *regs)
+{
+ current->thread.trap_no = trap_no(regs);
+
#ifdef CONFIG_KPROBES
- if (kprobe_breakpoint_handler(regs))
- return;
+ if (kprobe_breakpoint_handler(regs))
+ return;
#endif
#ifdef CONFIG_UPROBES
- if (uprobe_breakpoint_handler(regs))
- return;
+ if (uprobe_breakpoint_handler(regs))
+ return;
#endif
- die_if_kernel("Kernel mode ILLEGAL", regs, vector);
#ifndef CONFIG_CPU_NO_USER_BKPT
- if (*(uint16_t *)instruction_pointer(regs) != USR_BKPT)
+ if (*(uint16_t *)instruction_pointer(regs) != USR_BKPT) {
+ send_sig(SIGTRAP, current, 0);
+ return;
+ }
#endif
- {
- sig = SIGILL;
- break;
- }
- /* gdbserver breakpoint */
+
+ do_trap_error(regs, SIGILL, ILL_ILLOPC, regs->pc,
+ "Oops - illegal instruction exception");
+}
+
+asmlinkage void do_trap_fpe(struct pt_regs *regs)
+{
+#ifdef CONFIG_CPU_HAS_FP
+ return fpu_fpe(regs);
+#else
+ do_trap_error(regs, SIGILL, ILL_ILLOPC, regs->pc,
+ "Oops - fpu instruction exception");
+#endif
+}
+
+asmlinkage void do_trap_priv(struct pt_regs *regs)
+{
+#ifdef CONFIG_CPU_HAS_FP
+ if (user_mode(regs) && fpu_libc_helper(regs))
+ return;
+#endif
+ do_trap_error(regs, SIGILL, ILL_PRVOPC, regs->pc,
+ "Oops - illegal privileged exception");
+}
+
+asmlinkage void trap_c(struct pt_regs *regs)
+{
+ switch (trap_no(regs)) {
+ case VEC_ZERODIV:
+ do_trap_zdiv(regs);
+ break;
+ case VEC_TRACE:
+ do_trap_bkpt(regs);
+ break;
+ case VEC_ILLEGAL:
+ do_trap_illinsn(regs);
+ break;
case VEC_TRAP1:
- /* jtagserver breakpoint */
case VEC_BREAKPOINT:
- die_if_kernel("Kernel mode BKPT", regs, vector);
- info.si_code = TRAP_BRKPT;
- sig = SIGTRAP;
+ do_trap_bkpt(regs);
break;
case VEC_ACCESS:
- tsk->thread.trap_no = vector;
- return buserr(regs);
-#ifdef CONFIG_CPU_NEED_SOFTALIGN
+ do_trap_buserr(regs);
+ break;
case VEC_ALIGN:
- tsk->thread.trap_no = vector;
- return csky_alignment(regs);
-#endif
-#ifdef CONFIG_CPU_HAS_FPU
+ do_trap_misaligned(regs);
+ break;
case VEC_FPE:
- tsk->thread.trap_no = vector;
- die_if_kernel("Kernel mode FPE", regs, vector);
- return fpu_fpe(regs);
+ do_trap_fpe(regs);
+ break;
case VEC_PRIV:
- tsk->thread.trap_no = vector;
- die_if_kernel("Kernel mode PRIV", regs, vector);
- if (fpu_libc_helper(regs))
- return;
-#endif
+ do_trap_priv(regs);
+ break;
default:
- sig = SIGSEGV;
+ do_trap_unknown(regs);
break;
}
-
- tsk->thread.trap_no = vector;
-
- send_sig(sig, current, 0);
}
diff --git a/arch/csky/mm/fault.c b/arch/csky/mm/fault.c
index 0b9cbf2..b1dce9f 100644
--- a/arch/csky/mm/fault.c
+++ b/arch/csky/mm/fault.c
@@ -183,13 +183,13 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long write,
bad_area_nosemaphore:
/* User mode accesses just cause a SIGSEGV */
if (user_mode(regs)) {
- tsk->thread.trap_no = (regs->sr >> 16) & 0xff;
+ tsk->thread.trap_no = trap_no(regs);
force_sig_fault(SIGSEGV, si_code, (void __user *)address);
return;
}
no_context:
- tsk->thread.trap_no = (regs->sr >> 16) & 0xff;
+ tsk->thread.trap_no = trap_no(regs);
/* Are we prepared to handle this kernel fault? */
if (fixup_exception(regs))
@@ -202,10 +202,10 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long write,
bust_spinlocks(1);
pr_alert("Unable to handle kernel paging request at virtual "
"address 0x%08lx, pc: 0x%08lx\n", address, regs->pc);
- die_if_kernel("Oops", regs, write);
+ die(regs, "Oops");
out_of_memory:
- tsk->thread.trap_no = (regs->sr >> 16) & 0xff;
+ tsk->thread.trap_no = trap_no(regs);
/*
* We ran out of memory, call the OOM killer, and return the userspace
@@ -215,7 +215,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long write,
return;
do_sigbus:
- tsk->thread.trap_no = (regs->sr >> 16) & 0xff;
+ tsk->thread.trap_no = trap_no(regs);
mmap_read_unlock(mm);
--
2.7.4