Commit cd074557 authored by Will Deacon's avatar Will Deacon
Browse files

Merge branch 'for-next/entry' into for-next/core 

* for-next/entry:
  arm64: syscall: unmask DAIF earlier for SVCs
parents 0f4f768f f130ac0a

arch/arm64/kernel/entry-common.c

+32 −0
Original line number Diff line number Diff line
@@ -355,6 +355,35 @@ static bool cortex_a76_erratum_1463225_debug_handler(struct pt_regs *regs) 
}

#endif /* CONFIG_ARM64_ERRATUM_1463225 */



/*

 * As per the ABI exit SME streaming mode and clear the SVE state not

 * shared with FPSIMD on syscall entry.

 */

static inline void fp_user_discard(void)

{

	/*

	 * If SME is active then exit streaming mode.  If ZA is active

	 * then flush the SVE registers but leave userspace access to

	 * both SVE and SME enabled, otherwise disable SME for the

	 * task and fall through to disabling SVE too.  This means

	 * that after a syscall we never have any streaming mode

	 * register state to track, if this changes the KVM code will

	 * need updating.

	 */

	if (system_supports_sme())

		sme_smstop_sm();



	if (!system_supports_sve())

		return;



	if (test_thread_flag(TIF_SVE)) {

		unsigned int sve_vq_minus_one;



		sve_vq_minus_one = sve_vq_from_vl(task_get_sve_vl(current)) - 1;

		sve_flush_live(true, sve_vq_minus_one);

	}

}



UNHANDLED(el1t, 64, sync)

UNHANDLED(el1t, 64, irq)

UNHANDLED(el1t, 64, fiq)
@@ -644,6 +673,8 @@ static void noinstr el0_svc(struct pt_regs *regs) 
{

	enter_from_user_mode(regs);

	cortex_a76_erratum_1463225_svc_handler();

	fp_user_discard();

	local_daif_restore(DAIF_PROCCTX);

	do_el0_svc(regs);

	exit_to_user_mode(regs);

}
@@ -783,6 +814,7 @@ static void noinstr el0_svc_compat(struct pt_regs *regs) 
{

	enter_from_user_mode(regs);

	cortex_a76_erratum_1463225_svc_handler();

	local_daif_restore(DAIF_PROCCTX);

	do_el0_svc_compat(regs);

	exit_to_user_mode(regs);

}

arch/arm64/kernel/syscall.c

+0 −33
Original line number Diff line number Diff line
@@ -8,7 +8,6 @@ 
#include <linux/randomize_kstack.h>

#include <linux/syscalls.h>



#include <asm/daifflags.h>

#include <asm/debug-monitors.h>

#include <asm/exception.h>

#include <asm/fpsimd.h>
@@ -101,8 +100,6 @@ static void el0_svc_common(struct pt_regs *regs, int scno, int sc_nr, 
	 * (Similarly for HVC and SMC elsewhere.)

	 */



	local_daif_restore(DAIF_PROCCTX);



	if (flags & _TIF_MTE_ASYNC_FAULT) {

		/*

		 * Process the asynchronous tag check fault before the actual
@@ -153,38 +150,8 @@ static void el0_svc_common(struct pt_regs *regs, int scno, int sc_nr, 
	syscall_trace_exit(regs);

}



/*

 * As per the ABI exit SME streaming mode and clear the SVE state not

 * shared with FPSIMD on syscall entry.

 */

static inline void fp_user_discard(void)

{

	/*

	 * If SME is active then exit streaming mode.  If ZA is active

	 * then flush the SVE registers but leave userspace access to

	 * both SVE and SME enabled, otherwise disable SME for the

	 * task and fall through to disabling SVE too.  This means

	 * that after a syscall we never have any streaming mode

	 * register state to track, if this changes the KVM code will

	 * need updating.

	 */

	if (system_supports_sme())

		sme_smstop_sm();



	if (!system_supports_sve())

		return;



	if (test_thread_flag(TIF_SVE)) {

		unsigned int sve_vq_minus_one;



		sve_vq_minus_one = sve_vq_from_vl(task_get_sve_vl(current)) - 1;

		sve_flush_live(true, sve_vq_minus_one);

	}

}



void do_el0_svc(struct pt_regs *regs)

{

	fp_user_discard();

	el0_svc_common(regs, regs->regs[8], __NR_syscalls, sys_call_table);

}