[REVIEW][PATCH 05/22] signal/m68k: Use force_sig_fault where appropriate

From: Eric W. Biederman
Date: Fri Apr 20 2018 - 10:40:50 EST


Filling in struct siginfo before calling force_sig_info a tedious and
error prone process, where once in a great while the wrong fields
are filled out, and siginfo has been inconsistently cleared.

Simplify this process by using the helper force_sig_fault. Which
takes as a parameters all of the information it needs, ensures
all of the fiddly bits of filling in struct siginfo are done properly
and then calls force_sig_info.

In short about a 5 line reduction in code for every time force_sig_info
is called, which makes the calling function clearer.

Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Cc: linux-m68k@xxxxxxxxxxxxxxxxxxxx
Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
---
arch/m68k/kernel/traps.c | 60 ++++++++++++++++++++----------------------------
arch/m68k/mm/fault.c | 25 +++++++++-----------
2 files changed, 36 insertions(+), 49 deletions(-)

diff --git a/arch/m68k/kernel/traps.c b/arch/m68k/kernel/traps.c
index 0a00b476236d..b2fd000b9285 100644
--- a/arch/m68k/kernel/traps.c
+++ b/arch/m68k/kernel/traps.c
@@ -1007,11 +1007,10 @@ void bad_super_trap (struct frame *fp)

asmlinkage void trap_c(struct frame *fp)
{
- int sig;
+ int sig, si_code;
+ void __user *addr;
int vector = (fp->ptregs.vector >> 2) & 0xff;
- siginfo_t info;

- clear_siginfo(&info);
if (fp->ptregs.sr & PS_S) {
if (vector == VEC_TRACE) {
/* traced a trapping instruction on a 68020/30,
@@ -1030,21 +1029,21 @@ asmlinkage void trap_c(struct frame *fp)
/* send the appropriate signal to the user program */
switch (vector) {
case VEC_ADDRERR:
- info.si_code = BUS_ADRALN;
+ si_code = BUS_ADRALN;
sig = SIGBUS;
break;
case VEC_ILLEGAL:
case VEC_LINE10:
case VEC_LINE11:
- info.si_code = ILL_ILLOPC;
+ si_code = ILL_ILLOPC;
sig = SIGILL;
break;
case VEC_PRIV:
- info.si_code = ILL_PRVOPC;
+ si_code = ILL_PRVOPC;
sig = SIGILL;
break;
case VEC_COPROC:
- info.si_code = ILL_COPROC;
+ si_code = ILL_COPROC;
sig = SIGILL;
break;
case VEC_TRAP1:
@@ -1061,76 +1060,74 @@ asmlinkage void trap_c(struct frame *fp)
case VEC_TRAP12:
case VEC_TRAP13:
case VEC_TRAP14:
- info.si_code = ILL_ILLTRP;
+ si_code = ILL_ILLTRP;
sig = SIGILL;
break;
case VEC_FPBRUC:
case VEC_FPOE:
case VEC_FPNAN:
- info.si_code = FPE_FLTINV;
+ si_code = FPE_FLTINV;
sig = SIGFPE;
break;
case VEC_FPIR:
- info.si_code = FPE_FLTRES;
+ si_code = FPE_FLTRES;
sig = SIGFPE;
break;
case VEC_FPDIVZ:
- info.si_code = FPE_FLTDIV;
+ si_code = FPE_FLTDIV;
sig = SIGFPE;
break;
case VEC_FPUNDER:
- info.si_code = FPE_FLTUND;
+ si_code = FPE_FLTUND;
sig = SIGFPE;
break;
case VEC_FPOVER:
- info.si_code = FPE_FLTOVF;
+ si_code = FPE_FLTOVF;
sig = SIGFPE;
break;
case VEC_ZERODIV:
- info.si_code = FPE_INTDIV;
+ si_code = FPE_INTDIV;
sig = SIGFPE;
break;
case VEC_CHK:
case VEC_TRAP:
- info.si_code = FPE_INTOVF;
+ si_code = FPE_INTOVF;
sig = SIGFPE;
break;
case VEC_TRACE: /* ptrace single step */
- info.si_code = TRAP_TRACE;
+ si_code = TRAP_TRACE;
sig = SIGTRAP;
break;
case VEC_TRAP15: /* breakpoint */
- info.si_code = TRAP_BRKPT;
+ si_code = TRAP_BRKPT;
sig = SIGTRAP;
break;
default:
- info.si_code = ILL_ILLOPC;
+ si_code = ILL_ILLOPC;
sig = SIGILL;
break;
}
- info.si_signo = sig;
- info.si_errno = 0;
switch (fp->ptregs.format) {
default:
- info.si_addr = (void *) fp->ptregs.pc;
+ addr = (void __user *) fp->ptregs.pc;
break;
case 2:
- info.si_addr = (void *) fp->un.fmt2.iaddr;
+ addr = (void __user *) fp->un.fmt2.iaddr;
break;
case 7:
- info.si_addr = (void *) fp->un.fmt7.effaddr;
+ addr = (void __user *) fp->un.fmt7.effaddr;
break;
case 9:
- info.si_addr = (void *) fp->un.fmt9.iaddr;
+ addr = (void __user *) fp->un.fmt9.iaddr;
break;
case 10:
- info.si_addr = (void *) fp->un.fmta.daddr;
+ addr = (void __user *) fp->un.fmta.daddr;
break;
case 11:
- info.si_addr = (void *) fp->un.fmtb.daddr;
+ addr = (void __user*) fp->un.fmtb.daddr;
break;
}
- force_sig_info (sig, &info, current);
+ force_sig_fault(sig, si_code, addr, current);
}

void die_if_kernel (char *str, struct pt_regs *fp, int nr)
@@ -1162,13 +1159,6 @@ asmlinkage void fpsp040_die(void)
#ifdef CONFIG_M68KFPU_EMU
asmlinkage void fpemu_signal(int signal, int code, void *addr)
{
- siginfo_t info;
-
- clear_siginfo(&info);
- info.si_signo = signal;
- info.si_errno = 0;
- info.si_code = code;
- info.si_addr = addr;
- force_sig_info(signal, &info, current);
+ force_sig_fault(signal, code, addr, current);
}
#endif
diff --git a/arch/m68k/mm/fault.c b/arch/m68k/mm/fault.c
index 03253c4f8e6a..f2ff3779875a 100644
--- a/arch/m68k/mm/fault.c
+++ b/arch/m68k/mm/fault.c
@@ -21,35 +21,32 @@ extern void die_if_kernel(char *, struct pt_regs *, long);

int send_fault_sig(struct pt_regs *regs)
{
- siginfo_t siginfo;
+ int signo, si_code;
+ void __user *addr;

- clear_siginfo(&siginfo);
- siginfo.si_signo = current->thread.signo;
- siginfo.si_code = current->thread.code;
- siginfo.si_addr = (void *)current->thread.faddr;
- pr_debug("send_fault_sig: %p,%d,%d\n", siginfo.si_addr,
- siginfo.si_signo, siginfo.si_code);
+ signo = current->thread.signo;
+ si_code = current->thread.code;
+ addr = (void __user *)current->thread.faddr;
+ pr_debug("send_fault_sig: %p,%d,%d\n", addr, signo, si_code);

if (user_mode(regs)) {
- force_sig_info(siginfo.si_signo,
- &siginfo, current);
+ force_sig_fault(signo, si_code, addr, current);
} else {
if (fixup_exception(regs))
return -1;

- //if (siginfo.si_signo == SIGBUS)
- // force_sig_info(siginfo.si_signo,
- // &siginfo, current);
+ //if (signo == SIGBUS)
+ // force_sig_fault(si_signo, si_code, addr, current);

/*
* Oops. The kernel tried to access some bad page. We'll have to
* terminate things with extreme prejudice.
*/
- if ((unsigned long)siginfo.si_addr < PAGE_SIZE)
+ if ((unsigned long)addr < PAGE_SIZE)
pr_alert("Unable to handle kernel NULL pointer dereference");
else
pr_alert("Unable to handle kernel access");
- pr_cont(" at virtual address %p\n", siginfo.si_addr);
+ pr_cont(" at virtual address %p\n", addr);
die_if_kernel("Oops", regs, 0 /*error_code*/);
do_exit(SIGKILL);
}
--
2.14.1