Commit 13840229 authored by Kristina Martsenko's avatar Kristina Martsenko Committed by Catalin Marinas
Browse files

arm64: mops: Handle MOPS exceptions from EL1 



We will soon be using MOPS instructions in the kernel, so wire up the
exception handler to handle exceptions from EL1 caused by the copy/set
operation being stopped and resumed on a different type of CPU.

Add a helper for advancing the single step state machine, similarly to
what the EL0 exception handler does.

Signed-off-by: default avatarKristina Martsenko <kristina.martsenko@arm.com>
Link: https://lore.kernel.org/r/20240930161051.3777828-3-kristina.martsenko@arm.com


Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent c56c599d

arch/arm64/include/asm/debug-monitors.h

+1 −0
Original line number Diff line number Diff line
@@ -105,6 +105,7 @@ void kernel_enable_single_step(struct pt_regs *regs); 
void kernel_disable_single_step(void);

int kernel_active_single_step(void);

void kernel_rewind_single_step(struct pt_regs *regs);

void kernel_fastforward_single_step(struct pt_regs *regs);



#ifdef CONFIG_HAVE_HW_BREAKPOINT

int reinstall_suspended_bps(struct pt_regs *regs);

arch/arm64/include/asm/exception.h

+1 −0
Original line number Diff line number Diff line
@@ -73,6 +73,7 @@ void do_el0_svc_compat(struct pt_regs *regs); 
void do_el0_fpac(struct pt_regs *regs, unsigned long esr);

void do_el1_fpac(struct pt_regs *regs, unsigned long esr);

void do_el0_mops(struct pt_regs *regs, unsigned long esr);

void do_el1_mops(struct pt_regs *regs, unsigned long esr);

void do_serror(struct pt_regs *regs, unsigned long esr);

void do_signal(struct pt_regs *regs);

arch/arm64/kernel/debug-monitors.c

+5 −0
Original line number Diff line number Diff line
@@ -441,6 +441,11 @@ void kernel_rewind_single_step(struct pt_regs *regs) 
	set_regs_spsr_ss(regs);

}



void kernel_fastforward_single_step(struct pt_regs *regs)

{

	clear_regs_spsr_ss(regs);

}



/* ptrace API */

void user_enable_single_step(struct task_struct *task)

{

arch/arm64/kernel/entry-common.c

+12 −0
Original line number Diff line number Diff line
@@ -463,6 +463,15 @@ static void noinstr el1_bti(struct pt_regs *regs, unsigned long esr) 
	exit_to_kernel_mode(regs);

}



static void noinstr el1_mops(struct pt_regs *regs, unsigned long esr)

{

	enter_from_kernel_mode(regs);

	local_daif_inherit(regs);

	do_el1_mops(regs, esr);

	local_daif_mask();

	exit_to_kernel_mode(regs);

}



static void noinstr el1_dbg(struct pt_regs *regs, unsigned long esr)

{

	unsigned long far = read_sysreg(far_el1);
@@ -505,6 +514,9 @@ asmlinkage void noinstr el1h_64_sync_handler(struct pt_regs *regs) 
	case ESR_ELx_EC_BTI:

		el1_bti(regs, esr);

		break;

	case ESR_ELx_EC_MOPS:

		el1_mops(regs, esr);

		break;

	case ESR_ELx_EC_BREAKPT_CUR:

	case ESR_ELx_EC_SOFTSTP_CUR:

	case ESR_ELx_EC_WATCHPT_CUR:

arch/arm64/kernel/traps.c

+7 −0
Original line number Diff line number Diff line
@@ -531,6 +531,13 @@ void do_el0_mops(struct pt_regs *regs, unsigned long esr) 
	user_fastforward_single_step(current);

}



void do_el1_mops(struct pt_regs *regs, unsigned long esr)

{

	arm64_mops_reset_regs(&regs->user_regs, esr);



	kernel_fastforward_single_step(regs);

}



#define __user_cache_maint(insn, address, res)			\

	if (address >= TASK_SIZE_MAX) {				\

		res = -EFAULT;					\