[REVIEW][PATCH 09/22] signal/nds32: Use force_sig_fault where appropriate

From: Eric W. Biederman
Date: Fri Apr 20 2018 - 10:41:37 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: Greentime Hu <green.hu@xxxxxxxxx>
Cc: Vincent Chen <deanbo422@xxxxxxxxx>
Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
---
arch/nds32/kernel/traps.c | 20 ++++----------------
arch/nds32/mm/fault.c | 19 +++++--------------
2 files changed, 9 insertions(+), 30 deletions(-)

diff --git a/arch/nds32/kernel/traps.c b/arch/nds32/kernel/traps.c
index 46911768f4b5..636d1c7aa895 100644
--- a/arch/nds32/kernel/traps.c
+++ b/arch/nds32/kernel/traps.c
@@ -222,20 +222,13 @@ void die_if_kernel(const char *str, struct pt_regs *regs, int err)

int bad_syscall(int n, struct pt_regs *regs)
{
- siginfo_t info;
-
if (current->personality != PER_LINUX) {
send_sig(SIGSEGV, current, 1);
return regs->uregs[0];
}

- clear_siginfo(&info);
- info.si_signo = SIGILL;
- info.si_errno = 0;
- info.si_code = ILL_ILLTRP;
- info.si_addr = (void __user *)instruction_pointer(regs) - 4;
-
- force_sig_info(SIGILL, &info, current);
+ force_sig_fault(SIGILL, ILL_ILLTRP,
+ (void __user *)instruction_pointer(regs) - 4, current);
die_if_kernel("Oops - bad syscall", regs, n);
return regs->uregs[0];
}
@@ -288,16 +281,11 @@ void __init early_trap_init(void)
void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs,
int error_code, int si_code)
{
- struct siginfo info;
-
tsk->thread.trap_no = ENTRY_DEBUG_RELATED;
tsk->thread.error_code = error_code;

- clear_siginfo(&info);
- info.si_signo = SIGTRAP;
- info.si_code = si_code;
- info.si_addr = (void __user *)instruction_pointer(regs);
- force_sig_info(SIGTRAP, &info, tsk);
+ force_sig_fault(SIGTRAP, si_code
+ (void __user *)instruction_pointer(regs), tsk);
}

void do_debug_trap(unsigned long entry, unsigned long addr,
diff --git a/arch/nds32/mm/fault.c b/arch/nds32/mm/fault.c
index 876ee01ff80a..9bdb7c3ecbb6 100644
--- a/arch/nds32/mm/fault.c
+++ b/arch/nds32/mm/fault.c
@@ -72,16 +72,15 @@ void do_page_fault(unsigned long entry, unsigned long addr,
struct task_struct *tsk;
struct mm_struct *mm;
struct vm_area_struct *vma;
- siginfo_t info;
+ int si_code;
int fault;
unsigned int mask = VM_READ | VM_WRITE | VM_EXEC;
unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;

- clear_siginfo(&info);
error_code = error_code & (ITYPE_mskINST | ITYPE_mskETYPE);
tsk = current;
mm = tsk->mm;
- info.si_code = SEGV_MAPERR;
+ si_code = SEGV_MAPERR;
/*
* We fault-in kernel-space virtual memory on-demand. The
* 'reference' page table is init_mm.pgd.
@@ -162,7 +161,7 @@ void do_page_fault(unsigned long entry, unsigned long addr,
*/

good_area:
- info.si_code = SEGV_ACCERR;
+ si_code = SEGV_ACCERR;

/* first do some preliminary protection checks */
if (entry == ENTRY_PTE_NOT_PRESENT) {
@@ -267,11 +266,7 @@ void do_page_fault(unsigned long entry, unsigned long addr,
tsk->thread.address = addr;
tsk->thread.error_code = error_code;
tsk->thread.trap_no = entry;
- info.si_signo = SIGSEGV;
- info.si_errno = 0;
- /* info.si_code has been set above */
- info.si_addr = (void *)addr;
- force_sig_info(SIGSEGV, &info, tsk);
+ force_sig_fault(SIGSEGV, si_code, (void __user *)addr, tsk);
return;
}

@@ -340,11 +335,7 @@ void do_page_fault(unsigned long entry, unsigned long addr,
tsk->thread.address = addr;
tsk->thread.error_code = error_code;
tsk->thread.trap_no = entry;
- info.si_signo = SIGBUS;
- info.si_errno = 0;
- info.si_code = BUS_ADRERR;
- info.si_addr = (void *)addr;
- force_sig_info(SIGBUS, &info, tsk);
+ force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *)addr, tsk);

return;

--
2.14.1