linux-kernel - [REVIEW][PATCH 09/22] signal/nds32: Use force_sig

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Date:   Fri, 20 Apr 2018 09:37:58 -0500
From:   "Eric W. Biederman" <ebiederm@...ssion.com>
To:     linux-arch@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org,
        "Eric W. Biederman" <ebiederm@...ssion.com>,
        Greentime Hu <green.hu@...il.com>,
        Vincent Chen <deanbo422@...il.com>
Subject: [REVIEW][PATCH 09/22] signal/nds32: Use force_sig_fault where appropriate

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@...il.com>
Cc: Vincent Chen <deanbo422@...il.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@...ssion.com>
---
 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