Re: [REVIEW][PATCH 13/22] signal/parisc: Use force_sig_fault where appropriate

From: Helge Deller
Date: Sat Apr 21 2018 - 13:24:40 EST

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In reply to: Eric W. Biederman: "[REVIEW][PATCH 13/22] signal/parisc: Use force_sig_fault where appropriate"
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On 20.04.2018 16:38, Eric W. Biederman wrote:
> 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: James Bottomley <jejb@xxxxxxxxxxxxxxxx>
> Cc: Helge Deller <deller@xxxxxx>
> Cc: linux-parisc@xxxxxxxxxxxxxxx
> Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>

I pulled this whole patch series from your git tree and
booted it on 32- and 64-bit parisc kernels.

Acked-by: Helge Deller <deller@xxxxxx> # parisc

Thanks!
Helge

> ---
> arch/parisc/kernel/ptrace.c | 11 ++------
> arch/parisc/kernel/traps.c | 63 ++++++++++++++----------------------------
> arch/parisc/kernel/unaligned.c | 16 +++--------
> arch/parisc/math-emu/driver.c | 9 ++----
> arch/parisc/mm/fault.c | 25 +++++++----------
> 5 files changed, 39 insertions(+), 85 deletions(-)
>
> diff --git a/arch/parisc/kernel/ptrace.c b/arch/parisc/kernel/ptrace.c
> index b1c12ceb1c88..7aa1d4d0d444 100644
> --- a/arch/parisc/kernel/ptrace.c
> +++ b/arch/parisc/kernel/ptrace.c
> @@ -76,8 +76,6 @@ void user_enable_single_step(struct task_struct *task)
> set_tsk_thread_flag(task, TIF_SINGLESTEP);
>
> if (pa_psw(task)->n) {
> - struct siginfo si;
> -
> /* Nullified, just crank over the queue. */
> task_regs(task)->iaoq[0] = task_regs(task)->iaoq[1];
> task_regs(task)->iasq[0] = task_regs(task)->iasq[1];
> @@ -90,12 +88,9 @@ void user_enable_single_step(struct task_struct *task)
> ptrace_disable(task);
> /* Don't wake up the task, but let the
> parent know something happened. */
> - clear_siginfo(&si);
> - si.si_code = TRAP_TRACE;
> - si.si_addr = (void __user *) (task_regs(task)->iaoq[0] & ~3);
> - si.si_signo = SIGTRAP;
> - si.si_errno = 0;
> - force_sig_info(SIGTRAP, &si, task);
> + force_sig_fault(SIGTRAP, TRAP_TRACE,
> + (void __user *) (task_regs(task)->iaoq[0] & ~3),
> + task);
> /* notify_parent(task, SIGCHLD); */
> return;
> }
> diff --git a/arch/parisc/kernel/traps.c b/arch/parisc/kernel/traps.c
> index 98f9f2f85940..132b09c657ff 100644
> --- a/arch/parisc/kernel/traps.c
> +++ b/arch/parisc/kernel/traps.c
> @@ -297,14 +297,8 @@ void die_if_kernel(char *str, struct pt_regs *regs, long err)
> #define GDB_BREAK_INSN 0x10004
> static void handle_gdb_break(struct pt_regs *regs, int wot)
> {
> - struct siginfo si;
> -
> - clear_siginfo(&si);
> - si.si_signo = SIGTRAP;
> - si.si_errno = 0;
> - si.si_code = wot;
> - si.si_addr = (void __user *) (regs->iaoq[0] & ~3);
> - force_sig_info(SIGTRAP, &si, current);
> + force_sig_fault(SIGTRAP, wot,
> + (void __user *) (regs->iaoq[0] & ~3), current);
> }
>
> static void handle_break(struct pt_regs *regs)
> @@ -488,9 +482,8 @@ void notrace handle_interruption(int code, struct pt_regs *regs)
> {
> unsigned long fault_address = 0;
> unsigned long fault_space = 0;
> - struct siginfo si;
> + int si_code;
>
> - clear_siginfo(&si);
> if (code == 1)
> pdc_console_restart(); /* switch back to pdc if HPMC */
> else
> @@ -573,7 +566,7 @@ void notrace handle_interruption(int code, struct pt_regs *regs)
> case 8:
> /* Illegal instruction trap */
> die_if_kernel("Illegal instruction", regs, code);
> - si.si_code = ILL_ILLOPC;
> + si_code = ILL_ILLOPC;
> goto give_sigill;
>
> case 9:
> @@ -584,7 +577,7 @@ void notrace handle_interruption(int code, struct pt_regs *regs)
> case 10:
> /* Privileged operation trap */
> die_if_kernel("Privileged operation", regs, code);
> - si.si_code = ILL_PRVOPC;
> + si_code = ILL_PRVOPC;
> goto give_sigill;
>
> case 11:
> @@ -607,20 +600,16 @@ void notrace handle_interruption(int code, struct pt_regs *regs)
> }
>
> die_if_kernel("Privileged register usage", regs, code);
> - si.si_code = ILL_PRVREG;
> + si_code = ILL_PRVREG;
> give_sigill:
> - si.si_signo = SIGILL;
> - si.si_errno = 0;
> - si.si_addr = (void __user *) regs->iaoq[0];
> - force_sig_info(SIGILL, &si, current);
> + force_sig_fault(SIGILL, si_code,
> + (void __user *) regs->iaoq[0], current);
> return;
>
> case 12:
> /* Overflow Trap, let the userland signal handler do the cleanup */
> - si.si_signo = SIGFPE;
> - si.si_code = FPE_INTOVF;
> - si.si_addr = (void __user *) regs->iaoq[0];
> - force_sig_info(SIGFPE, &si, current);
> + force_sig_fault(SIGFPE, FPE_INTOVF,
> + (void __user *) regs->iaoq[0], current);
> return;
>
> case 13:
> @@ -628,13 +617,11 @@ void notrace handle_interruption(int code, struct pt_regs *regs)
> The condition succeeds in an instruction which traps
> on condition */
> if(user_mode(regs)){
> - si.si_signo = SIGFPE;
> /* Let userspace app figure it out from the insn pointed
> * to by si_addr.
> */
> - si.si_code = FPE_CONDTRAP;
> - si.si_addr = (void __user *) regs->iaoq[0];
> - force_sig_info(SIGFPE, &si, current);
> + force_sig_fault(SIGFPE, FPE_CONDTRAP,
> + (void __user *) regs->iaoq[0], current);
> return;
> }
> /* The kernel doesn't want to handle condition codes */
> @@ -743,14 +730,10 @@ void notrace handle_interruption(int code, struct pt_regs *regs)
> return;
>
> die_if_kernel("Protection id trap", regs, code);
> - si.si_code = SEGV_MAPERR;
> - si.si_signo = SIGSEGV;
> - si.si_errno = 0;
> - if (code == 7)
> - si.si_addr = (void __user *) regs->iaoq[0];
> - else
> - si.si_addr = (void __user *) regs->ior;
> - force_sig_info(SIGSEGV, &si, current);
> + force_sig_fault(SIGSEGV, SEGV_MAPERR,
> + (code == 7)?
> + ((void __user *) regs->iaoq[0]) :
> + ((void __user *) regs->ior), current);
> return;
>
> case 28:
> @@ -764,11 +747,8 @@ void notrace handle_interruption(int code, struct pt_regs *regs)
> "handle_interruption() pid=%d command='%s'\n",
> task_pid_nr(current), current->comm);
> /* SIGBUS, for lack of a better one. */
> - si.si_signo = SIGBUS;
> - si.si_code = BUS_OBJERR;
> - si.si_errno = 0;
> - si.si_addr = (void __user *) regs->ior;
> - force_sig_info(SIGBUS, &si, current);
> + force_sig_fault(SIGBUS, BUS_OBJERR,
> + (void __user *)regs->ior, current);
> return;
> }
> pdc_chassis_send_status(PDC_CHASSIS_DIRECT_PANIC);
> @@ -783,11 +763,8 @@ void notrace handle_interruption(int code, struct pt_regs *regs)
> "User fault %d on space 0x%08lx, pid=%d command='%s'\n",
> code, fault_space,
> task_pid_nr(current), current->comm);
> - si.si_signo = SIGSEGV;
> - si.si_errno = 0;
> - si.si_code = SEGV_MAPERR;
> - si.si_addr = (void __user *) regs->ior;
> - force_sig_info(SIGSEGV, &si, current);
> + force_sig_fault(SIGSEGV, SEGV_MAPERR,
> + (void __user *)regs->ior, current);
> return;
> }
> }
> diff --git a/arch/parisc/kernel/unaligned.c b/arch/parisc/kernel/unaligned.c
> index 30b7c7f6c471..932bfc0b7cd8 100644
> --- a/arch/parisc/kernel/unaligned.c
> +++ b/arch/parisc/kernel/unaligned.c
> @@ -452,10 +452,8 @@ void handle_unaligned(struct pt_regs *regs)
> unsigned long newbase = R1(regs->iir)?regs->gr[R1(regs->iir)]:0;
> int modify = 0;
> int ret = ERR_NOTHANDLED;
> - struct siginfo si;
> register int flop=0; /* true if this is a flop */
>
> - clear_siginfo(&si);
> __inc_irq_stat(irq_unaligned_count);
>
> /* log a message with pacing */
> @@ -691,21 +689,15 @@ void handle_unaligned(struct pt_regs *regs)
>
> if (ret == ERR_PAGEFAULT)
> {
> - si.si_signo = SIGSEGV;
> - si.si_errno = 0;
> - si.si_code = SEGV_MAPERR;
> - si.si_addr = (void __user *)regs->ior;
> - force_sig_info(SIGSEGV, &si, current);
> + force_sig_fault(SIGSEGV, SEGV_MAPERR,
> + (void __user *)regs->ior, current);
> }
> else
> {
> force_sigbus:
> /* couldn't handle it ... */
> - si.si_signo = SIGBUS;
> - si.si_errno = 0;
> - si.si_code = BUS_ADRALN;
> - si.si_addr = (void __user *)regs->ior;
> - force_sig_info(SIGBUS, &si, current);
> + force_sig_fault(SIGBUS, BUS_ADRALN,
> + (void __user *)regs->ior, current);
> }
>
> return;
> diff --git a/arch/parisc/math-emu/driver.c b/arch/parisc/math-emu/driver.c
> index 0d10efb53361..0590e05571d1 100644
> --- a/arch/parisc/math-emu/driver.c
> +++ b/arch/parisc/math-emu/driver.c
> @@ -81,7 +81,6 @@ int
> handle_fpe(struct pt_regs *regs)
> {
> extern void printbinary(unsigned long x, int nbits);
> - struct siginfo si;
> unsigned int orig_sw, sw;
> int signalcode;
> /* need an intermediate copy of float regs because FPU emulation
> @@ -93,7 +92,6 @@ handle_fpe(struct pt_regs *regs)
> */
> __u64 frcopy[36];
>
> - clear_siginfo(&si);
> memcpy(frcopy, regs->fr, sizeof regs->fr);
> frcopy[32] = 0;
>
> @@ -118,11 +116,8 @@ handle_fpe(struct pt_regs *regs)
>
> memcpy(regs->fr, frcopy, sizeof regs->fr);
> if (signalcode != 0) {
> - si.si_signo = signalcode >> 24;
> - si.si_errno = 0;
> - si.si_code = signalcode & 0xffffff;
> - si.si_addr = (void __user *) regs->iaoq[0];
> - force_sig_info(si.si_signo, &si, current);
> + force_sig_fault(signalcode >> 24, signalcode & 0xffffff,
> + (void __user *) regs->iaoq[0], current);
> return -1;
> }
>
> diff --git a/arch/parisc/mm/fault.c b/arch/parisc/mm/fault.c
> index 51215b0048ef..a80117980fc2 100644
> --- a/arch/parisc/mm/fault.c
> +++ b/arch/parisc/mm/fault.c
> @@ -353,23 +353,22 @@ void do_page_fault(struct pt_regs *regs, unsigned long code,
> up_read(&mm->mmap_sem);
>
> if (user_mode(regs)) {
> - struct siginfo si;
> + int signo, si_code;
>
> - clear_siginfo(&si);
> switch (code) {
> case 15: /* Data TLB miss fault/Data page fault */
> /* send SIGSEGV when outside of vma */
> if (!vma ||
> address < vma->vm_start || address >= vma->vm_end) {
> - si.si_signo = SIGSEGV;
> - si.si_code = SEGV_MAPERR;
> + signo = SIGSEGV;
> + si_code = SEGV_MAPERR;
> break;
> }
>
> /* send SIGSEGV for wrong permissions */
> if ((vma->vm_flags & acc_type) != acc_type) {
> - si.si_signo = SIGSEGV;
> - si.si_code = SEGV_ACCERR;
> + signo = SIGSEGV;
> + si_code = SEGV_ACCERR;
> break;
> }
>
> @@ -377,17 +376,16 @@ void do_page_fault(struct pt_regs *regs, unsigned long code,
> /* fall through */
> case 17: /* NA data TLB miss / page fault */
> case 18: /* Unaligned access - PCXS only */
> - si.si_signo = SIGBUS;
> - si.si_code = (code == 18) ? BUS_ADRALN : BUS_ADRERR;
> + signo = SIGBUS;
> + si_code = (code == 18) ? BUS_ADRALN : BUS_ADRERR;
> break;
> case 16: /* Non-access instruction TLB miss fault */
> case 26: /* PCXL: Data memory access rights trap */
> default:
> - si.si_signo = SIGSEGV;
> - si.si_code = (code == 26) ? SEGV_ACCERR : SEGV_MAPERR;
> + signo = SIGSEGV;
> + si_code = (code == 26) ? SEGV_ACCERR : SEGV_MAPERR;
> break;
> }
> -
> #ifdef CONFIG_MEMORY_FAILURE
> if (fault & (VM_FAULT_HWPOISON|VM_FAULT_HWPOISON_LARGE)) {
> unsigned int lsb = 0;
> @@ -409,12 +407,9 @@ void do_page_fault(struct pt_regs *regs, unsigned long code,
> return;
> }
> #endif
> -
> show_signal_msg(regs, code, address, tsk, vma);
>
> - si.si_errno = 0;
> - si.si_addr = (void __user *) address;
> - force_sig_info(si.si_signo, &si, current);
> + force_sig_fault(signo, si_code, (void __user *) address, current);
> return;
> }
>
>

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