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Commit c870f14e authored by Mark Rutland's avatar Mark Rutland Committed by Catalin Marinas
Browse files

arm64: Unify kernel fault reporting 



In do_page_fault(), we handle some kernel faults early, and simply
die() with a message. For faults handled later, we dump the faulting
address, decode the ESR, walk the page tables, and perform a number of
steps to ensure that this data is reported.

Let's unify the handling of fatal kernel faults with a new
die_kernel_fault() helper, handling all of these details. This is
largely the same as the existing logic in __do_kernel_fault(), except
that addresses are consistently padded to 16 hex characters, as would be
expected for a 64-bit address.

The messages currently logged in do_page_fault are adjusted to fit into
the die_kernel_fault() message template.

Acked-by: default avatarWill Deacon <will.deacon@arm.com>
Signed-off-by: default avatarMark Rutland <mark.rutland@arm.com>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 969e61ba

arch/arm64/mm/fault.c

+23 −14
Original line number Diff line number Diff line
@@ -255,6 +255,22 @@ static inline bool is_el1_permission_fault(unsigned int esr, 
	return false;

}



static void die_kernel_fault(const char *msg, unsigned long addr,

			     unsigned int esr, struct pt_regs *regs)

{

	bust_spinlocks(1);



	pr_alert("Unable to handle kernel %s at virtual address %016lx\n", msg,

		 addr);



	mem_abort_decode(esr);



	show_pte(addr);

	die("Oops", regs, esr);

	bust_spinlocks(0);

	do_exit(SIGKILL);

}



static void __do_kernel_fault(unsigned long addr, unsigned int esr,

			      struct pt_regs *regs)

{
@@ -267,8 +283,6 @@ static void __do_kernel_fault(unsigned long addr, unsigned int esr, 
	if (!is_el1_instruction_abort(esr) && fixup_exception(regs))

		return;



	bust_spinlocks(1);



	if (is_el1_permission_fault(esr, regs, addr)) {

		if (esr & ESR_ELx_WNR)

			msg = "write to read-only memory";
@@ -280,15 +294,7 @@ static void __do_kernel_fault(unsigned long addr, unsigned int esr, 
		msg = "paging request";

	}



	pr_alert("Unable to handle kernel %s at virtual address %08lx\n", msg,

		 addr);



	mem_abort_decode(esr);



	show_pte(addr);

	die("Oops", regs, esr);

	bust_spinlocks(0);

	do_exit(SIGKILL);

	die_kernel_fault(msg, addr, esr, regs);

}



static void __do_user_fault(struct siginfo *info, unsigned int esr)
@@ -399,13 +405,16 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr, 
	if (addr < TASK_SIZE && is_el1_permission_fault(esr, regs, addr)) {

		/* regs->orig_addr_limit may be 0 if we entered from EL0 */

		if (regs->orig_addr_limit == KERNEL_DS)

			die("Accessing user space memory with fs=KERNEL_DS", regs, esr);

			die_kernel_fault("access to user memory with fs=KERNEL_DS",

					 addr, esr, regs);



		if (is_el1_instruction_abort(esr))

			die("Attempting to execute userspace memory", regs, esr);

			die_kernel_fault("execution of user memory",

					 addr, esr, regs);



		if (!search_exception_tables(regs->pc))

			die("Accessing user space memory outside uaccess.h routines", regs, esr);

			die_kernel_fault("access to user memory outside uaccess routines",

					 addr, esr, regs);

	}



	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr);