signal/alpha: si_trapno is only used with SIGFPE and SIGTRAP TRAP_UNK

While reviewing the signal handlers on alpha it became clear that
si_trapno is only set to a non-zero value when sending SIGFPE and when
sending SITGRAP with si_code TRAP_UNK.

Add send_sig_fault_trapno and send SIGTRAP TRAP_UNK, and SIGFPE with it.

Remove the define of __ARCH_SI_TRAPNO and remove the always zero
si_trapno parameter from send_sig_fault and force_sig_fault.

v1: https://lkml.kernel.org/r/m1eeers7q7.fsf_-_@fess.ebiederm.org
v2: https://lkml.kernel.org/r/20210505141101.11519-7-ebiederm@xmission.com
Link: https://lkml.kernel.org/r/87h7gvxx7l.fsf_-_@disp2133
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

diff --git a/arch/alpha/include/uapi/asm/siginfo.h b/arch/alpha/include/uapi/asm/siginfo.h
index 6e1a2af..e08eae8 100644 (file)
--- a/arch/alpha/include/uapi/asm/siginfo.h
+++ b/arch/alpha/include/uapi/asm/siginfo.h
@@ -2,8 +2,6 @@
 #ifndef _ALPHA_SIGINFO_H
 #define _ALPHA_SIGINFO_H
 
-#define __ARCH_SI_TRAPNO
-
 #include <asm-generic/siginfo.h>
 
 #endif

diff --git a/arch/alpha/kernel/osf_sys.c b/arch/alpha/kernel/osf_sys.c
index d5367a1..bbdb1a9 100644 (file)
--- a/arch/alpha/kernel/osf_sys.c
+++ b/arch/alpha/kernel/osf_sys.c
@@ -876,7 +876,7 @@ SYSCALL_DEFINE5(osf_setsysinfo, unsigned long, op, void __user *, buffer,
                        if (fex & IEEE_TRAP_ENABLE_DZE) si_code = FPE_FLTDIV;
                        if (fex & IEEE_TRAP_ENABLE_INV) si_code = FPE_FLTINV;
 
-                       send_sig_fault(SIGFPE, si_code,
+                       send_sig_fault_trapno(SIGFPE, si_code,
                                       (void __user *)NULL,  /* FIXME */
                                       0, current);
                }

diff --git a/arch/alpha/kernel/signal.c b/arch/alpha/kernel/signal.c
index 948b897..bc077ba 100644 (file)
--- a/arch/alpha/kernel/signal.c
+++ b/arch/alpha/kernel/signal.c
@@ -219,7 +219,7 @@ do_sigreturn(struct sigcontext __user *sc)
 
        /* Send SIGTRAP if we're single-stepping: */
        if (ptrace_cancel_bpt (current)) {
-               send_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *) regs->pc, 0,
+               send_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *) regs->pc,
                               current);
        }
        return;
@@ -247,7 +247,7 @@ do_rt_sigreturn(struct rt_sigframe __user *frame)
 
        /* Send SIGTRAP if we're single-stepping: */
        if (ptrace_cancel_bpt (current)) {
-               send_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *) regs->pc, 0,
+               send_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *) regs->pc,
                               current);
        }
        return;

diff --git a/arch/alpha/kernel/traps.c b/arch/alpha/kernel/traps.c
index 921d4b6..e9e3de1 100644 (file)
--- a/arch/alpha/kernel/traps.c
+++ b/arch/alpha/kernel/traps.c
@@ -227,7 +227,7 @@ do_entArith(unsigned long summary, unsigned long write_mask,
        }
        die_if_kernel("Arithmetic fault", regs, 0, NULL);
 
-       send_sig_fault(SIGFPE, si_code, (void __user *) regs->pc, 0, current);
+       send_sig_fault_trapno(SIGFPE, si_code, (void __user *) regs->pc, 0, current);
 }
 
 asmlinkage void
@@ -268,13 +268,13 @@ do_entIF(unsigned long type, struct pt_regs *regs)
                        regs->pc -= 4;  /* make pc point to former bpt */
                }
 
-               send_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->pc, 0,
+               send_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->pc,
                               current);
                return;
 
              case 1: /* bugcheck */
-               send_sig_fault(SIGTRAP, TRAP_UNK, (void __user *) regs->pc, 0,
-                              current);
+               send_sig_fault_trapno(SIGTRAP, TRAP_UNK,
+                                     (void __user *) regs->pc, 0, current);
                return;
                
              case 2: /* gentrap */
@@ -335,8 +335,8 @@ do_entIF(unsigned long type, struct pt_regs *regs)
                        break;
                }
 
-               send_sig_fault(signo, code, (void __user *) regs->pc, regs->r16,
-                              current);
+               send_sig_fault_trapno(signo, code, (void __user *) regs->pc,
+                                     regs->r16, current);
                return;
 
              case 4: /* opDEC */
@@ -360,9 +360,9 @@ do_entIF(unsigned long type, struct pt_regs *regs)
                        if (si_code == 0)
                                return;
                        if (si_code > 0) {
-                               send_sig_fault(SIGFPE, si_code,
-                                              (void __user *) regs->pc, 0,
-                                              current);
+                               send_sig_fault_trapno(SIGFPE, si_code,
+                                                     (void __user *) regs->pc,
+                                                     0, current);
                                return;
                        }
                }
@@ -387,7 +387,7 @@ do_entIF(unsigned long type, struct pt_regs *regs)
                      ;
        }
 
-       send_sig_fault(SIGILL, ILL_ILLOPC, (void __user *)regs->pc, 0, current);
+       send_sig_fault(SIGILL, ILL_ILLOPC, (void __user *)regs->pc, current);
 }
 
 /* There is an ifdef in the PALcode in MILO that enables a 
@@ -402,7 +402,7 @@ do_entDbg(struct pt_regs *regs)
 {
        die_if_kernel("Instruction fault", regs, 0, NULL);
 
-       force_sig_fault(SIGILL, ILL_ILLOPC, (void __user *)regs->pc, 0);
+       force_sig_fault(SIGILL, ILL_ILLOPC, (void __user *)regs->pc);
 }
 
 
@@ -964,12 +964,12 @@ give_sigsegv:
                        si_code = SEGV_MAPERR;
                mmap_read_unlock(mm);
        }
-       send_sig_fault(SIGSEGV, si_code, va, 0, current);
+       send_sig_fault(SIGSEGV, si_code, va, current);
        return;
 
 give_sigbus:
        regs->pc -= 4;
-       send_sig_fault(SIGBUS, BUS_ADRALN, va, 0, current);
+       send_sig_fault(SIGBUS, BUS_ADRALN, va, current);
        return;
 }
 

diff --git a/arch/alpha/mm/fault.c b/arch/alpha/mm/fault.c
index 09172f0..eee5102 100644 (file)
--- a/arch/alpha/mm/fault.c
+++ b/arch/alpha/mm/fault.c
@@ -219,13 +219,13 @@ retry:
        mmap_read_unlock(mm);
        /* Send a sigbus, regardless of whether we were in kernel
           or user mode.  */
-       force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *) address, 0);
+       force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *) address);
        if (!user_mode(regs))
                goto no_context;
        return;
 
  do_sigsegv:
-       force_sig_fault(SIGSEGV, si_code, (void __user *) address, 0);
+       force_sig_fault(SIGSEGV, si_code, (void __user *) address);
        return;
 
 #ifdef CONFIG_ALPHA_LARGE_VMALLOC

diff --git a/include/linux/sched/signal.h b/include/linux/sched/signal.h
index 99a9ab2..6657184 100644 (file)
--- a/include/linux/sched/signal.h
+++ b/include/linux/sched/signal.h
@@ -330,6 +330,8 @@ int force_sig_perf(void __user *addr, u32 type, u64 sig_data);
 
 int force_sig_ptrace_errno_trap(int errno, void __user *addr);
 int force_sig_fault_trapno(int sig, int code, void __user *addr, int trapno);
+int send_sig_fault_trapno(int sig, int code, void __user *addr, int trapno,
+                       struct task_struct *t);
 
 extern int send_sig_info(int, struct kernel_siginfo *, struct task_struct *);
 extern void force_sigsegv(int sig);

diff --git a/kernel/signal.c b/kernel/signal.c
index 87a3742..ae06a42 100644 (file)
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1824,6 +1824,23 @@ int force_sig_fault_trapno(int sig, int code, void __user *addr, int trapno)
        return force_sig_info(&info);
 }
 
+/* For the rare architectures that include trap information using
+ * si_trapno.
+ */
+int send_sig_fault_trapno(int sig, int code, void __user *addr, int trapno,
+                         struct task_struct *t)
+{
+       struct kernel_siginfo info;
+
+       clear_siginfo(&info);
+       info.si_signo = sig;
+       info.si_errno = 0;
+       info.si_code  = code;
+       info.si_addr  = addr;
+       info.si_trapno = trapno;
+       return send_sig_info(info.si_signo, &info, t);
+}
+
 int kill_pgrp(struct pid *pid, int sig, int priv)
 {
        int ret;
@@ -3262,6 +3279,10 @@ enum siginfo_layout siginfo_layout(unsigned sig, int si_code)
                        else if (IS_ENABLED(CONFIG_SPARC) &&
                                 (sig == SIGILL) && (si_code == ILL_ILLTRP))
                                layout = SIL_FAULT_TRAPNO;
+                       else if (IS_ENABLED(CONFIG_ALPHA) &&
+                                ((sig == SIGFPE) ||
+                                 ((sig == SIGTRAP) && (si_code == TRAP_UNK))))
+                               layout = SIL_FAULT_TRAPNO;
 #ifdef __ARCH_SI_TRAPNO
                        else if (layout == SIL_FAULT)
                                layout = SIL_FAULT_TRAPNO;