[REVIEW][PATCH 1/4] signal/arm: Push siginfo generation into arm_notify_die

From: Eric W. Biederman
Date: Mon Sep 24 2018 - 08:12:09 EST

In arm_notify_die call force_sig_fault to let the generic
code handle siginfo generation.

This removes some boiler plate making the code easier to
maintain in the long run.

Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
---
arch/arm/include/asm/bug.h | 4 +--
arch/arm/kernel/swp_emulate.c | 16 ++++-----
arch/arm/kernel/traps.c | 63 ++++++++++-------------------------
arch/arm/mm/fault.c | 18 +++-------
4 files changed, 30 insertions(+), 71 deletions(-)

diff --git a/arch/arm/include/asm/bug.h b/arch/arm/include/asm/bug.h
index 237aa52d8733..36c951dd23b8 100644
--- a/arch/arm/include/asm/bug.h
+++ b/arch/arm/include/asm/bug.h
@@ -62,8 +62,8 @@ do { \
struct pt_regs;
void die(const char *msg, struct pt_regs *regs, int err);

-struct siginfo;
-void arm_notify_die(const char *str, struct pt_regs *regs, struct siginfo *info,
+void arm_notify_die(const char *str, struct pt_regs *regs,
+ int signo, int si_code, void __user *addr,
unsigned long err, unsigned long trap);

#ifdef CONFIG_ARM_LPAE
diff --git a/arch/arm/kernel/swp_emulate.c b/arch/arm/kernel/swp_emulate.c
index 80517f293eb9..a188d5e8ab7f 100644
--- a/arch/arm/kernel/swp_emulate.c
+++ b/arch/arm/kernel/swp_emulate.c
@@ -98,22 +98,20 @@ static int proc_status_show(struct seq_file *m, void *v)
*/
static void set_segfault(struct pt_regs *regs, unsigned long addr)
{
- siginfo_t info;
+ int si_code;

- clear_siginfo(&info);
down_read(&current->mm->mmap_sem);
if (find_vma(current->mm, addr) == NULL)
- info.si_code = SEGV_MAPERR;
+ si_code = SEGV_MAPERR;
else
- info.si_code = SEGV_ACCERR;
+ si_code = SEGV_ACCERR;
up_read(&current->mm->mmap_sem);

- info.si_signo = SIGSEGV;
- info.si_errno = 0;
- info.si_addr = (void *) instruction_pointer(regs);
-
pr_debug("SWP{B} emulation: access caused memory abort!\n");
- arm_notify_die("Illegal memory access", regs, &info, 0, 0);
+ arm_notify_die("Illegal memory access", regs,
+ SIGSEGV, si_code,
+ (void __user *)instruction_pointer(regs),
+ 0, 0);

abtcounter++;
}
diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index badf02ca3693..2d668cff8ef4 100644
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -365,13 +365,14 @@ void die(const char *str, struct pt_regs *regs, int err)
}

void arm_notify_die(const char *str, struct pt_regs *regs,
- struct siginfo *info, unsigned long err, unsigned long trap)
+ int signo, int si_code, void __user *addr,
+ unsigned long err, unsigned long trap)
{
if (user_mode(regs)) {
current->thread.error_code = err;
current->thread.trap_no = trap;

- force_sig_info(info->si_signo, info, current);
+ force_sig_fault(signo, si_code, addr, current);
} else {
die(str, regs, err);
}
@@ -438,10 +439,8 @@ int call_undef_hook(struct pt_regs *regs, unsigned int instr)
asmlinkage void do_undefinstr(struct pt_regs *regs)
{
unsigned int instr;
- siginfo_t info;
void __user *pc;

- clear_siginfo(&info);
pc = (void __user *)instruction_pointer(regs);

if (processor_mode(regs) == SVC_MODE) {
@@ -485,13 +484,8 @@ asmlinkage void do_undefinstr(struct pt_regs *regs)
dump_instr(KERN_INFO, regs);
}
#endif
-
- info.si_signo = SIGILL;
- info.si_errno = 0;
- info.si_code = ILL_ILLOPC;
- info.si_addr = pc;
-
- arm_notify_die("Oops - undefined instruction", regs, &info, 0, 6);
+ arm_notify_die("Oops - undefined instruction", regs,
+ SIGILL, ILL_ILLOPC, pc, 0, 6);
}
NOKPROBE_SYMBOL(do_undefinstr)

@@ -539,9 +533,6 @@ asmlinkage void bad_mode(struct pt_regs *regs, int reason)

static int bad_syscall(int n, struct pt_regs *regs)
{
- siginfo_t info;
-
- clear_siginfo(&info);
if ((current->personality & PER_MASK) != PER_LINUX) {
send_sig(SIGSEGV, current, 1);
return regs->ARM_r0;
@@ -555,13 +546,10 @@ static int bad_syscall(int n, struct pt_regs *regs)
}
#endif

- info.si_signo = SIGILL;
- info.si_errno = 0;
- info.si_code = ILL_ILLTRP;
- info.si_addr = (void __user *)instruction_pointer(regs) -
- (thumb_mode(regs) ? 2 : 4);
-
- arm_notify_die("Oops - bad syscall", regs, &info, n, 0);
+ arm_notify_die("Oops - bad syscall", regs, SIGILL, ILL_ILLTRP,
+ (void __user *)instruction_pointer(regs) -
+ (thumb_mode(regs) ? 2 : 4),
+ n, 0);

return regs->ARM_r0;
}
@@ -607,20 +595,13 @@ do_cache_op(unsigned long start, unsigned long end, int flags)
#define NR(x) ((__ARM_NR_##x) - __ARM_NR_BASE)
asmlinkage int arm_syscall(int no, struct pt_regs *regs)
{
- siginfo_t info;
-
- clear_siginfo(&info);
if ((no >> 16) != (__ARM_NR_BASE>> 16))
return bad_syscall(no, regs);

switch (no & 0xffff) {
case 0: /* branch through 0 */
- info.si_signo = SIGSEGV;
- info.si_errno = 0;
- info.si_code = SEGV_MAPERR;
- info.si_addr = NULL;
-
- arm_notify_die("branch through zero", regs, &info, 0, 0);
+ arm_notify_die("branch through zero", regs,
+ SIGSEGV, SEGV_MAPERR, NULL, 0, 0);
return 0;

case NR(breakpoint): /* SWI BREAK_POINT */
@@ -688,13 +669,10 @@ asmlinkage int arm_syscall(int no, struct pt_regs *regs)
}
}
#endif
- info.si_signo = SIGILL;
- info.si_errno = 0;
- info.si_code = ILL_ILLTRP;
- info.si_addr = (void __user *)instruction_pointer(regs) -
- (thumb_mode(regs) ? 2 : 4);
-
- arm_notify_die("Oops - bad syscall(2)", regs, &info, no, 0);
+ arm_notify_die("Oops - bad syscall(2)", regs, SIGILL, ILL_ILLTRP,
+ (void __user *)instruction_pointer(regs) -
+ (thumb_mode(regs) ? 2 : 4),
+ no, 0);
return 0;
}

@@ -744,9 +722,6 @@ asmlinkage void
baddataabort(int code, unsigned long instr, struct pt_regs *regs)
{
unsigned long addr = instruction_pointer(regs);
- siginfo_t info;
-
- clear_siginfo(&info);

#ifdef CONFIG_DEBUG_USER
if (user_debug & UDBG_BADABORT) {
@@ -757,12 +732,8 @@ baddataabort(int code, unsigned long instr, struct pt_regs *regs)
}
#endif

- info.si_signo = SIGILL;
- info.si_errno = 0;
- info.si_code = ILL_ILLOPC;
- info.si_addr = (void __user *)addr;
-
- arm_notify_die("unknown data abort code", regs, &info, instr, 0);
+ arm_notify_die("unknown data abort code", regs,
+ SIGILL, ILL_ILLOPC, (void __user *)addr, instr, 0);
}

void __readwrite_bug(const char *fn)
diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c
index 3232afb6fdc0..544d2c8c2775 100644
--- a/arch/arm/mm/fault.c
+++ b/arch/arm/mm/fault.c
@@ -554,7 +554,6 @@ asmlinkage void
do_DataAbort(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
{
const struct fsr_info *inf = fsr_info + fsr_fs(fsr);
- struct siginfo info;

if (!inf->fn(addr, fsr & ~FSR_LNX_PF, regs))
return;
@@ -563,12 +562,8 @@ do_DataAbort(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
inf->name, fsr, addr);
show_pte(current->mm, addr);

- clear_siginfo(&info);
- info.si_signo = inf->sig;
- info.si_errno = 0;
- info.si_code = inf->code;
- info.si_addr = (void __user *)addr;
- arm_notify_die("", regs, &info, fsr, 0);
+ arm_notify_die("", regs, inf->sig, inf->code, (void __user *)addr,
+ fsr, 0);
}

void __init
@@ -588,7 +583,6 @@ asmlinkage void
do_PrefetchAbort(unsigned long addr, unsigned int ifsr, struct pt_regs *regs)
{
const struct fsr_info *inf = ifsr_info + fsr_fs(ifsr);
- struct siginfo info;

if (!inf->fn(addr, ifsr | FSR_LNX_PF, regs))
return;
@@ -596,12 +590,8 @@ do_PrefetchAbort(unsigned long addr, unsigned int ifsr, struct pt_regs *regs)
pr_alert("Unhandled prefetch abort: %s (0x%03x) at 0x%08lx\n",
inf->name, ifsr, addr);

- clear_siginfo(&info);
- info.si_signo = inf->sig;
- info.si_errno = 0;
- info.si_code = inf->code;
- info.si_addr = (void __user *)addr;
- arm_notify_die("", regs, &info, ifsr, 0);
+ arm_notify_die("", regs, inf->sig, inf->code, (void __user *)addr,
+ ifsr, 0);
}

/*
--
2.17.1