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Subject[REVIEW][PATCH 20/22] signal/um: 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: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: user-mode-linux-devel@lists.sourceforge.net
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
arch/um/kernel/ptrace.c | 13 +++----------
arch/um/kernel/trap.c | 26 ++++++++------------------
2 files changed, 11 insertions(+), 28 deletions(-)

diff --git a/arch/um/kernel/ptrace.c b/arch/um/kernel/ptrace.c
index bc2a516c190f..1a1d88a4d940 100644
--- a/arch/um/kernel/ptrace.c
+++ b/arch/um/kernel/ptrace.c
@@ -115,17 +115,10 @@ long arch_ptrace(struct task_struct *child, long request,
static void send_sigtrap(struct task_struct *tsk, struct uml_pt_regs *regs,
int error_code)
{
- struct siginfo info;
-
- memset(&info, 0, sizeof(info));
- info.si_signo = SIGTRAP;
- info.si_code = TRAP_BRKPT;
-
- /* User-mode eip? */
- info.si_addr = UPT_IS_USER(regs) ? (void __user *) UPT_IP(regs) : NULL;
-
/* Send us the fake SIGTRAP */
- force_sig_info(SIGTRAP, &info, tsk);
+ force_sig_fault(SIGTRAP, TRAP_BRKPT,
+ /* User-mode eip? */
+ UPT_IS_USER(regs) ? (void __user *) UPT_IP(regs) : NULL, tsk);
}

/*
diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c
index 5f0ff17cd790..48b70dcb6963 100644
--- a/arch/um/kernel/trap.c
+++ b/arch/um/kernel/trap.c
@@ -162,14 +162,9 @@ static void show_segv_info(struct uml_pt_regs *regs)

static void bad_segv(struct faultinfo fi, unsigned long ip)
{
- struct siginfo si;
-
- clear_siginfo(&si);
- si.si_signo = SIGSEGV;
- si.si_code = SEGV_ACCERR;
- si.si_addr = (void __user *) FAULT_ADDRESS(fi);
current->thread.arch.faultinfo = fi;
- force_sig_info(SIGSEGV, &si, current);
+ force_sig_fault(SIGSEGV, SEGV_ACCERR, (void __user *) FAULT_ADDRESS(fi),
+ current);
}

void fatal_sigsegv(void)
@@ -215,13 +210,12 @@ void segv_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs)
unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user,
struct uml_pt_regs *regs)
{
- struct siginfo si;
jmp_buf *catcher;
+ int si_code;
int err;
int is_write = FAULT_WRITE(fi);
unsigned long address = FAULT_ADDRESS(fi);

- clear_siginfo(&si);
if (!is_user && regs)
current->thread.segv_regs = container_of(regs, struct pt_regs, regs);

@@ -241,7 +235,7 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user,

if (SEGV_IS_FIXABLE(&fi))
err = handle_page_fault(address, ip, is_write, is_user,
- &si.si_code);
+ &si_code);
else {
err = -EFAULT;
/*
@@ -273,18 +267,14 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user,
show_segv_info(regs);

if (err == -EACCES) {
- si.si_signo = SIGBUS;
- si.si_errno = 0;
- si.si_code = BUS_ADRERR;
- si.si_addr = (void __user *)address;
current->thread.arch.faultinfo = fi;
- force_sig_info(SIGBUS, &si, current);
+ force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *)address,
+ current);
} else {
BUG_ON(err != -EFAULT);
- si.si_signo = SIGSEGV;
- si.si_addr = (void __user *) address;
current->thread.arch.faultinfo = fi;
- force_sig_info(SIGSEGV, &si, current);
+ force_sig_fault(SIGSEGV, si_code, (void __user *) address,
+ current);
}

out:
--
2.14.1
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