x86/traps: Introduce fill_trap_info(), simplify DO_ERROR_INFO()

Extract the fill-siginfo code from DO_ERROR_INFO() into the new helper,
fill_trap_info().

It can calculate si_code and si_addr looking at trapnr, so we can remove
these arguments from DO_ERROR_INFO() and simplify the source code. The
generated code is the same, __builtin_constant_p(trapnr) == T.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>

diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index ab8dad7..1cf8a4c 100644 (file)
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -136,6 +136,33 @@ do_trap_no_signal(struct task_struct *tsk, int trapnr, char *str,
        return -1;
 }
 
+static void fill_trap_info(struct pt_regs *regs, int signr, int trapnr,
+                          siginfo_t *info)
+{
+       unsigned long siaddr;
+       int sicode;
+
+       switch (trapnr) {
+       case X86_TRAP_DE:
+               sicode = FPE_INTDIV;
+               siaddr = regs->ip;
+               break;
+       case X86_TRAP_UD:
+               sicode = ILL_ILLOPN;
+               siaddr = regs->ip;
+               break;
+       case X86_TRAP_AC:
+               sicode = BUS_ADRALN;
+               siaddr = 0;
+               break;
+       }
+
+       info->si_signo = signr;
+       info->si_errno = 0;
+       info->si_code = sicode;
+       info->si_addr = (void __user *)siaddr;
+}
+
 static void __kprobes
 do_trap(int trapnr, int signr, char *str, struct pt_regs *regs,
        long error_code, siginfo_t *info)
@@ -191,30 +218,26 @@ dotraplinkage void do_##name(struct pt_regs *regs, long error_code)       \
        do_error_trap(regs, error_code, str, trapnr, signr, NULL);      \
 }
 
-#define DO_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr)                \
+#define DO_ERROR_INFO(trapnr, signr, str, name)                                \
 dotraplinkage void do_##name(struct pt_regs *regs, long error_code)    \
 {                                                                      \
        siginfo_t info;                                                 \
                                                                        \
-       info.si_signo = signr;                                          \
-       info.si_errno = 0;                                              \
-       info.si_code = sicode;                                          \
-       info.si_addr = (void __user *)siaddr;                           \
-                                                                       \
+       fill_trap_info(regs, signr, trapnr, &info);                     \
        do_error_trap(regs, error_code, str, trapnr, signr, &info);     \
 }
 
-DO_ERROR_INFO(X86_TRAP_DE,     SIGFPE,  "divide error",                        divide_error,                FPE_INTDIV, regs->ip )
-DO_ERROR     (X86_TRAP_OF,     SIGSEGV, "overflow",                    overflow                                          )
-DO_ERROR     (X86_TRAP_BR,     SIGSEGV, "bounds",                      bounds                                            )
-DO_ERROR_INFO(X86_TRAP_UD,     SIGILL,  "invalid opcode",              invalid_op,                  ILL_ILLOPN, regs->ip )
-DO_ERROR     (X86_TRAP_OLD_MF, SIGFPE,  "coprocessor segment overrun", coprocessor_segment_overrun                       )
-DO_ERROR     (X86_TRAP_TS,     SIGSEGV, "invalid TSS",                 invalid_TSS                                       )
-DO_ERROR     (X86_TRAP_NP,     SIGBUS,  "segment not present",         segment_not_present                               )
+DO_ERROR_INFO(X86_TRAP_DE,     SIGFPE,  "divide error",                        divide_error)
+DO_ERROR     (X86_TRAP_OF,     SIGSEGV, "overflow",                    overflow)
+DO_ERROR     (X86_TRAP_BR,     SIGSEGV, "bounds",                      bounds)
+DO_ERROR_INFO(X86_TRAP_UD,     SIGILL,  "invalid opcode",              invalid_op)
+DO_ERROR     (X86_TRAP_OLD_MF, SIGFPE,  "coprocessor segment overrun", coprocessor_segment_overrun)
+DO_ERROR     (X86_TRAP_TS,     SIGSEGV, "invalid TSS",                 invalid_TSS)
+DO_ERROR     (X86_TRAP_NP,     SIGBUS,  "segment not present",         segment_not_present)
 #ifdef CONFIG_X86_32
-DO_ERROR     (X86_TRAP_SS,     SIGBUS,  "stack segment",               stack_segment                                     )
+DO_ERROR     (X86_TRAP_SS,     SIGBUS,  "stack segment",               stack_segment)
 #endif
-DO_ERROR_INFO(X86_TRAP_AC,     SIGBUS,  "alignment check",             alignment_check,             BUS_ADRALN, 0        )
+DO_ERROR_INFO(X86_TRAP_AC,     SIGBUS,  "alignment check",             alignment_check)
 
 #ifdef CONFIG_X86_64
 /* Runs on IST stack */