From: Guo Ren <guo...@linux.alibaba.com>

 - 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 <guo...@linux.alibaba.com>
Cc: Arnd Bergmann <a...@arndb.de>
---
 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

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