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Commit a11e67c2 authored by Richard Kuo's avatar Richard Kuo
Browse files

Hexagon: Signal and return path fixes 



This fixes the return value of sigreturn and moves the work pending check
into a c routine for readability and fixes the loop for multiple pending
signals.  Based on feedback from Al Viro.

Signed-off-by: default avatarRichard Kuo <rkuo@codeaurora.org>
parent 60c4ba99

arch/hexagon/include/uapi/asm/signal.h

+2 −0
Original line number Diff line number Diff line
@@ -21,6 +21,8 @@ 


extern unsigned long __rt_sigtramp_template[2];



void do_signal(struct pt_regs *regs);



#include <asm-generic/signal.h>



#endif

arch/hexagon/kernel/process.c

+41 −0
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ 
#include <linux/tick.h>

#include <linux/uaccess.h>

#include <linux/slab.h>

#include <linux/tracehook.h>



/*

 * Program thread launch.  Often defined as a macro in processor.h,
@@ -202,3 +203,43 @@ int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu) 
{

	return 0;

}





/*

 * Called on the exit path of event entry; see vm_entry.S

 *

 * Interrupts will already be disabled.

 *

 * Returns 0 if there's no need to re-check for more work.

 */



int do_work_pending(struct pt_regs *regs, u32 thread_info_flags)

{

	if (!(thread_info_flags & _TIF_ALLWORK_MASK)) {

		return 0;

	}  /* shortcut -- no work to be done */



	local_irq_enable();



	if (thread_info_flags & _TIF_NEED_RESCHED) {

		schedule();

		return 1;

	}



	if (thread_info_flags & _TIF_SIGPENDING) {

		do_signal(regs);

		return 1;

	}



	if (thread_info_flags & _TIF_NOTIFY_RESUME) {

		clear_thread_flag(TIF_NOTIFY_RESUME);

		tracehook_notify_resume(regs);

		if (current->replacement_session_keyring)

			key_replace_session_keyring();

		return 1;

	}



	/* Should not even reach here */

	panic("%s: bad thread_info flags 0x%08x\n", __func__,

		thread_info_flags);

}

arch/hexagon/kernel/signal.c

+5 −24
Original line number Diff line number Diff line
@@ -199,7 +199,7 @@ static void handle_signal(int sig, siginfo_t *info, struct k_sigaction *ka, 
/*

 * Called from return-from-event code.

 */

static void do_signal(struct pt_regs *regs)

void do_signal(struct pt_regs *regs)

{

	struct k_sigaction sigact;

	siginfo_t info;
@@ -216,8 +216,9 @@ static void do_signal(struct pt_regs *regs) 
	}



	/*

	 * If we came from a system call, handle the restart.

	 * No (more) signals; if we came from a system call, handle the restart.

	 */



	if (regs->syscall_nr >= 0) {

		switch (regs->r00) {

		case -ERESTARTNOHAND:
@@ -240,17 +241,6 @@ static void do_signal(struct pt_regs *regs) 
	restore_saved_sigmask();

}



void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags)

{

	if (thread_info_flags & _TIF_SIGPENDING)

		do_signal(regs);



	if (thread_info_flags & _TIF_NOTIFY_RESUME) {

		clear_thread_flag(TIF_NOTIFY_RESUME);

		tracehook_notify_resume(regs);

	}

}



/*

 * Architecture-specific wrappers for signal-related system calls

 */
@@ -278,21 +268,12 @@ asmlinkage int sys_rt_sigreturn(void) 
	/* Restore the user's stack as well */

	pt_psp(regs) = regs->r29;



	/*

	 * Leave a trace in the stack frame that this was a sigreturn.

	 * If the system call is to replay, we've already restored the

	 * number in the GPR slot and it will be regenerated on the

	 * new system call trap entry. Note that if restore_sigcontext()

	 * did something other than a bulk copy of the pt_regs struct,

	 * we could avoid this assignment by simply not overwriting

	 * regs->syscall_nr.

	 */

	regs->syscall_nr = __NR_rt_sigreturn;

	regs->syscall_nr = -1;



	if (restore_altstack(&frame->uc.uc_stack))

		goto badframe;



	return 0;

	return regs->r00;



badframe:

	force_sig(SIGSEGV, current);

arch/hexagon/kernel/traps.c

+1 −12
Original line number Diff line number Diff line
@@ -356,7 +356,6 @@ long sys_syscall(void) 


void do_trap0(struct pt_regs *regs)

{

	unsigned long syscallret = 0;

	syscall_fn syscall;



	switch (pt_cause(regs)) {
@@ -396,21 +395,11 @@ void do_trap0(struct pt_regs *regs) 
		} else {

			syscall = (syscall_fn)

				  (sys_call_table[regs->syscall_nr]);

			syscallret = syscall(regs->r00, regs->r01,

			regs->r00 = syscall(regs->r00, regs->r01,

				   regs->r02, regs->r03,

				   regs->r04, regs->r05);

		}



		/*

		 * If it was a sigreturn system call, don't overwrite

		 * r0 value in stack frame with return value.

		 *

		 * __NR_sigreturn doesn't seem to exist in new unistd.h

		 */



		if (regs->syscall_nr != __NR_rt_sigreturn)

			regs->r00 = syscallret;



		/* allow strace to get the syscall return state  */

		if (unlikely(test_thread_flag(TIF_SYSCALL_TRACE)))

			tracehook_report_syscall_exit(regs, 0);

arch/hexagon/kernel/vm_entry.S

+35 −52
Original line number Diff line number Diff line
@@ -274,6 +274,9 @@ event_dispatch: 
	callr	r1



	/*

	 * Coming back from the C-world, our thread info pointer

	 * should be in the designated register (usually R19)

	 *

	 * If we were in kernel mode, we don't need to check scheduler

	 * or signals if CONFIG_PREEMPT is not set.  If set, then it has

	 * to jump to a need_resched kind of block.
@@ -286,67 +289,43 @@ event_dispatch: 
#endif



	/*  "Nested control path" -- if the previous mode was kernel  */

	{

		R0 = memw(R29 + #_PT_ER_VMEST);

		R16.L = #LO(do_work_pending);

	}

	{

		P0 = tstbit(R0, #HVM_VMEST_UM_SFT);

		if (!P0.new) jump:nt restore_all;

		R16.H = #HI(do_work_pending);

		R0 = #VM_INT_DISABLE;

	}

	/*

	 * Returning from system call, normally coming back from user mode

	 */

return_from_syscall:

	/*  Disable interrupts while checking TIF  */

	R0 = #VM_INT_DISABLE

	trap1(#HVM_TRAP1_VMSETIE)



	/*

	 * Coming back from the C-world, our thread info pointer

	 * should be in the designated register (usually R19)

	 */

#if CONFIG_HEXAGON_ARCH_VERSION < 4

	R1.L = #LO(_TIF_ALLWORK_MASK)

	{

		R1.H = #HI(_TIF_ALLWORK_MASK);

		R0 = memw(THREADINFO_REG + #_THREAD_INFO_FLAGS);

	}

#else

	{

		R1 = ##_TIF_ALLWORK_MASK;

		R0 = memw(THREADINFO_REG + #_THREAD_INFO_FLAGS);

	}

#endif



	/*

	 * Compare against the "return to userspace" _TIF_WORK_MASK

	 * Check also the return from fork/system call, normally coming back from

	 * user mode

	 *

	 * R16 needs to have do_work_pending, and R0 should have VM_INT_DISABLE

	 */

	R1 = and(R1,R0);

	{ P0 = cmp.eq(R1,#0); if (!P0.new) jump:t work_pending;}

	jump restore_all;  /*  we're outta here!  */



work_pending:

check_work_pending:

	/*  Disable interrupts while checking TIF  */

	trap1(#HVM_TRAP1_VMSETIE)

	{

		P0 = tstbit(R1, #TIF_NEED_RESCHED);

		if (!P0.new) jump:nt work_notifysig;

		R0 = R29;  /*  regs should still be at top of stack  */

		R1 = memw(THREADINFO_REG + #_THREAD_INFO_FLAGS);

		callr R16;

	}

	call schedule

	jump return_from_syscall;  /*  check for more work  */



work_notifysig:

	/*  this is the part that's kind of fuzzy.  */

	R1 = and(R0, #(_TIF_SIGPENDING | _TIF_NOTIFY_RESUME));

	{

		P0 = cmp.eq(R1, #0);

		if P0.new jump:t restore_all;

	}

	{

		R1 = R0; 	/* unsigned long thread_info_flags */

		R0 = R29;	/* regs should still be at top of stack  */

		P0 = cmp.eq(R0, #0); if (!P0.new) jump:nt check_work_pending;

		R0 = #VM_INT_DISABLE;

	}

	call do_notify_resume



restore_all:

	/* Disable interrupts, if they weren't already, before reg restore.  */

	R0 = #VM_INT_DISABLE

	/*

	 * Disable interrupts, if they weren't already, before reg restore.

	 * R0 gets preloaded with #VM_INT_DISABLE before we get here.

	 */

	trap1(#HVM_TRAP1_VMSETIE)



	/*  do the setregs here for VM 0.5  */
@@ -371,6 +350,7 @@ restore_all: 
	trap1(#HVM_TRAP1_VMRTE)

	/* Notreached */





	.globl _K_enter_genex

_K_enter_genex:

	vm_event_entry(do_genex)
@@ -390,9 +370,12 @@ _K_enter_machcheck: 


	.globl ret_from_fork

ret_from_fork:

	call schedule_tail

	P0 = cmp.eq(R24, #0);

	if P0 jump return_from_syscall

	R0 = R25;

	callr R24

	jump return_from_syscall
 
	{

		call schedule_tail;

		R16.H = #HI(do_work_pending);

	}

	{

		R16.L = #LO(do_work_pending);

		R0 = #VM_INT_DISABLE;

		jump check_work_pending;

	}