[REVIEW][PATCH 01/22] signal/alpha: Use send_sig_fault where appropriate

From: Eric W. Biederman
Date: Fri Apr 20 2018 - 10:40:06 EST


Filling in struct siginfo before calling send_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 send_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 send_sig_info.

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

Cc: Richard Henderson <rth@xxxxxxxxxxx>
Cc: Ivan Kokshaysky <ink@xxxxxxxxxxxxxxxxxxxx>
Cc: linux-alpha@xxxxxxxxxxxxxxx
Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
---
arch/alpha/kernel/osf_sys.c | 10 ++-----
arch/alpha/kernel/signal.c | 22 +++-----------
arch/alpha/kernel/traps.c | 71 +++++++++++----------------------------------
3 files changed, 24 insertions(+), 79 deletions(-)

diff --git a/arch/alpha/kernel/osf_sys.c b/arch/alpha/kernel/osf_sys.c
index bb3619118926..6e921754c8fc 100644
--- a/arch/alpha/kernel/osf_sys.c
+++ b/arch/alpha/kernel/osf_sys.c
@@ -871,7 +871,6 @@ SYSCALL_DEFINE5(osf_setsysinfo, unsigned long, op, void __user *, buffer,
send a signal. Old exceptions are not signaled. */
fex = (exc >> IEEE_STATUS_TO_EXCSUM_SHIFT) & swcr;
if (fex) {
- siginfo_t info;
int si_code = FPE_FLTUNK;

if (fex & IEEE_TRAP_ENABLE_DNO) si_code = FPE_FLTUND;
@@ -881,12 +880,9 @@ 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;

- clear_siginfo(&info);
- info.si_signo = SIGFPE;
- info.si_errno = 0;
- info.si_code = si_code;
- info.si_addr = NULL; /* FIXME */
- send_sig_info(SIGFPE, &info, current);
+ send_sig_fault(SIGFPE, si_code,
+ (void __user *)NULL, /* FIXME */
+ 0, current);
}
return 0;
}
diff --git a/arch/alpha/kernel/signal.c b/arch/alpha/kernel/signal.c
index cd306e602313..8c0c4ee0be6e 100644
--- a/arch/alpha/kernel/signal.c
+++ b/arch/alpha/kernel/signal.c
@@ -219,15 +219,8 @@ do_sigreturn(struct sigcontext __user *sc)

/* Send SIGTRAP if we're single-stepping: */
if (ptrace_cancel_bpt (current)) {
- siginfo_t info;
-
- clear_siginfo(&info);
- info.si_signo = SIGTRAP;
- info.si_errno = 0;
- info.si_code = TRAP_BRKPT;
- info.si_addr = (void __user *) regs->pc;
- info.si_trapno = 0;
- send_sig_info(SIGTRAP, &info, current);
+ send_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *) regs->pc, 0,
+ current);
}
return;

@@ -254,15 +247,8 @@ do_rt_sigreturn(struct rt_sigframe __user *frame)

/* Send SIGTRAP if we're single-stepping: */
if (ptrace_cancel_bpt (current)) {
- siginfo_t info;
-
- clear_siginfo(&info);
- info.si_signo = SIGTRAP;
- info.si_errno = 0;
- info.si_code = TRAP_BRKPT;
- info.si_addr = (void __user *) regs->pc;
- info.si_trapno = 0;
- send_sig_info(SIGTRAP, &info, current);
+ send_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *) regs->pc, 0,
+ current);
}
return;

diff --git a/arch/alpha/kernel/traps.c b/arch/alpha/kernel/traps.c
index 242c83d86ace..106a1692fca0 100644
--- a/arch/alpha/kernel/traps.c
+++ b/arch/alpha/kernel/traps.c
@@ -213,7 +213,6 @@ do_entArith(unsigned long summary, unsigned long write_mask,
struct pt_regs *regs)
{
long si_code = FPE_FLTINV;
- siginfo_t info;

if (summary & 1) {
/* Software-completion summary bit is set, so try to
@@ -228,21 +227,14 @@ do_entArith(unsigned long summary, unsigned long write_mask,
}
die_if_kernel("Arithmetic fault", regs, 0, NULL);

- clear_siginfo(&info);
- info.si_signo = SIGFPE;
- info.si_errno = 0;
- info.si_code = si_code;
- info.si_addr = (void __user *) regs->pc;
- send_sig_info(SIGFPE, &info, current);
+ send_sig_fault(SIGFPE, si_code, (void __user *) regs->pc, 0, current);
}

asmlinkage void
do_entIF(unsigned long type, struct pt_regs *regs)
{
- siginfo_t info;
int signo, code;

- clear_siginfo(&info);
if ((regs->ps & ~IPL_MAX) == 0) {
if (type == 1) {
const unsigned int *data
@@ -272,31 +264,20 @@ do_entIF(unsigned long type, struct pt_regs *regs)

switch (type) {
case 0: /* breakpoint */
- info.si_signo = SIGTRAP;
- info.si_errno = 0;
- info.si_code = TRAP_BRKPT;
- info.si_trapno = 0;
- info.si_addr = (void __user *) regs->pc;
-
if (ptrace_cancel_bpt(current)) {
regs->pc -= 4; /* make pc point to former bpt */
}

- send_sig_info(SIGTRAP, &info, current);
+ send_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->pc, 0,
+ current);
return;

case 1: /* bugcheck */
- info.si_signo = SIGTRAP;
- info.si_errno = 0;
- info.si_code = TRAP_UNK;
- info.si_addr = (void __user *) regs->pc;
- info.si_trapno = 0;
- send_sig_info(SIGTRAP, &info, current);
+ send_sig_fault(SIGTRAP, TRAP_UNK, (void __user *) regs->pc, 0,
+ current);
return;

case 2: /* gentrap */
- info.si_addr = (void __user *) regs->pc;
- info.si_trapno = regs->r16;
switch ((long) regs->r16) {
case GEN_INTOVF:
signo = SIGFPE;
@@ -354,11 +335,8 @@ do_entIF(unsigned long type, struct pt_regs *regs)
break;
}

- info.si_signo = signo;
- info.si_errno = 0;
- info.si_code = code;
- info.si_addr = (void __user *) regs->pc;
- send_sig_info(signo, &info, current);
+ send_sig_fault(signo, code, (void __user *) regs->pc, regs->r16,
+ current);
return;

case 4: /* opDEC */
@@ -382,11 +360,9 @@ do_entIF(unsigned long type, struct pt_regs *regs)
if (si_code == 0)
return;
if (si_code > 0) {
- info.si_signo = SIGFPE;
- info.si_errno = 0;
- info.si_code = si_code;
- info.si_addr = (void __user *) regs->pc;
- send_sig_info(SIGFPE, &info, current);
+ send_sig_fault(SIGFPE, si_code,
+ (void __user *) regs->pc, 0,
+ current);
return;
}
}
@@ -411,11 +387,7 @@ do_entIF(unsigned long type, struct pt_regs *regs)
;
}

- info.si_signo = SIGILL;
- info.si_errno = 0;
- info.si_code = ILL_ILLOPC;
- info.si_addr = (void __user *) regs->pc;
- send_sig_info(SIGILL, &info, current);
+ send_sig_fault(SIGILL, ILL_ILLOPC, (void __user *)regs->pc, 0, current);
}

/* There is an ifdef in the PALcode in MILO that enables a
@@ -761,11 +733,9 @@ do_entUnaUser(void __user * va, unsigned long opcode,

unsigned long tmp1, tmp2, tmp3, tmp4;
unsigned long fake_reg, *reg_addr = &fake_reg;
- siginfo_t info;
+ int si_code;
long error;

- clear_siginfo(&info);
-
/* Check the UAC bits to decide what the user wants us to do
with the unaliged access. */

@@ -986,34 +956,27 @@ do_entUnaUser(void __user * va, unsigned long opcode,

give_sigsegv:
regs->pc -= 4; /* make pc point to faulting insn */
- info.si_signo = SIGSEGV;
- info.si_errno = 0;

/* We need to replicate some of the logic in mm/fault.c,
since we don't have access to the fault code in the
exception handling return path. */
if ((unsigned long)va >= TASK_SIZE)
- info.si_code = SEGV_ACCERR;
+ si_code = SEGV_ACCERR;
else {
struct mm_struct *mm = current->mm;
down_read(&mm->mmap_sem);
if (find_vma(mm, (unsigned long)va))
- info.si_code = SEGV_ACCERR;
+ si_code = SEGV_ACCERR;
else
- info.si_code = SEGV_MAPERR;
+ si_code = SEGV_MAPERR;
up_read(&mm->mmap_sem);
}
- info.si_addr = va;
- send_sig_info(SIGSEGV, &info, current);
+ send_sig_fault(SIGSEGV, si_code, va, 0, current);
return;

give_sigbus:
regs->pc -= 4;
- info.si_signo = SIGBUS;
- info.si_errno = 0;
- info.si_code = BUS_ADRALN;
- info.si_addr = va;
- send_sig_info(SIGBUS, &info, current);
+ send_sig_fault(SIGBUS, BUS_ADRALN, va, 0, current);
return;
}

--
2.14.1

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