Commit b966f227 authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

powerpc/syscall: Do not check unsupported scv vector on PPC32 



Only book3s/64 has scv. No need to check the 0x7ff0 trap on 32 or 64e.
For that, add a helper trap_is_unsupported_scv() similar to
trap_is_scv().

And ignore the scv parameter in syscall_exit_prepare (Save 14 cycles
346 => 332 cycles)

Signed-off-by: default avatarChristophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/fb87b205ae8eb8c623f33bb316801acf95a831e6.1612898425.git.christophe.leroy@csgroup.eu
parent eb595eca

arch/powerpc/include/asm/ptrace.h

+5 −0
Original line number Diff line number Diff line
@@ -229,6 +229,11 @@ static inline bool trap_is_scv(struct pt_regs *regs) 
	return (IS_ENABLED(CONFIG_PPC_BOOK3S_64) && TRAP(regs) == 0x3000);

}



static inline bool trap_is_unsupported_scv(struct pt_regs *regs)

{

	return IS_ENABLED(CONFIG_PPC_BOOK3S_64) && TRAP(regs) == 0x7ff0;

}



static inline bool trap_is_syscall(struct pt_regs *regs)

{

	return (trap_is_scv(regs) || TRAP(regs) == 0xc00);

arch/powerpc/kernel/interrupt.c

+5 −4
Original line number Diff line number Diff line
@@ -88,7 +88,7 @@ notrace long system_call_exception(long r3, long r4, long r5, 
	local_irq_enable();



	if (unlikely(current_thread_info()->flags & _TIF_SYSCALL_DOTRACE)) {

		if (unlikely(regs->trap == 0x7ff0)) {

		if (unlikely(trap_is_unsupported_scv(regs))) {

			/* Unsupported scv vector */

			_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);

			return regs->gpr[3];
@@ -111,7 +111,7 @@ notrace long system_call_exception(long r3, long r4, long r5, 
		r8 = regs->gpr[8];



	} else if (unlikely(r0 >= NR_syscalls)) {

		if (unlikely(regs->trap == 0x7ff0)) {

		if (unlikely(trap_is_unsupported_scv(regs))) {

			/* Unsupported scv vector */

			_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);

			return regs->gpr[3];
@@ -220,6 +220,7 @@ notrace unsigned long syscall_exit_prepare(unsigned long r3, 
	unsigned long *ti_flagsp = &current_thread_info()->flags;

	unsigned long ti_flags;

	unsigned long ret = 0;

	bool is_not_scv = !IS_ENABLED(CONFIG_PPC_BOOK3S_64) || !scv;



	CT_WARN_ON(ct_state() == CONTEXT_USER);
@@ -234,7 +235,7 @@ notrace unsigned long syscall_exit_prepare(unsigned long r3, 


	ti_flags = *ti_flagsp;



	if (unlikely(r3 >= (unsigned long)-MAX_ERRNO) && !scv) {

	if (unlikely(r3 >= (unsigned long)-MAX_ERRNO) && is_not_scv) {

		if (likely(!(ti_flags & (_TIF_NOERROR | _TIF_RESTOREALL)))) {

			r3 = -r3;

			regs->ccr |= 0x10000000; /* Set SO bit in CR */
@@ -305,7 +306,7 @@ notrace unsigned long syscall_exit_prepare(unsigned long r3, 
	user_enter_irqoff();



	/* scv need not set RI=0 because SRRs are not used */

	if (unlikely(!__prep_irq_for_enabled_exit(!scv))) {

	if (unlikely(!__prep_irq_for_enabled_exit(is_not_scv))) {

		user_exit_irqoff();

		local_irq_enable();

		local_irq_disable();