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Commit c49bd02f authored by Anshuman Khandual's avatar Anshuman Khandual Committed by Catalin Marinas
Browse files

arm64/mm: Document write abort detection from ESR 



This patch adds an is_write_abort() wrapper and documents the detection
of the abort type on cache maintenance operations.

Cc: Will Deacon <will.deacon@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Acked-by: default avatarMark Rutland <mark.rutland@arm.com>
Signed-off-by: default avatarAnshuman Khandual <anshuman.khandual@arm.com>
[catalin.marinas@arm.com: only keep the is_write_abort() wrapper]
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 8e01076a

arch/arm64/mm/fault.c

+10 −1
Original line number Diff line number Diff line
@@ -435,6 +435,15 @@ static bool is_el0_instruction_abort(unsigned int esr) 
	return ESR_ELx_EC(esr) == ESR_ELx_EC_IABT_LOW;

}



/*

 * Note: not valid for EL1 DC IVAC, but we never use that such that it

 * should fault. EL0 cannot issue DC IVAC (undef).

 */

static bool is_write_abort(unsigned int esr)

{

	return (esr & ESR_ELx_WNR) && !(esr & ESR_ELx_CM);

}



static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,

				   struct pt_regs *regs)

{
@@ -460,7 +469,7 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr, 
	if (is_el0_instruction_abort(esr)) {

		vm_flags = VM_EXEC;

		mm_flags |= FAULT_FLAG_INSTRUCTION;

	} else if ((esr & ESR_ELx_WNR) && !(esr & ESR_ELx_CM)) {

	} else if (is_write_abort(esr)) {

		vm_flags = VM_WRITE;

		mm_flags |= FAULT_FLAG_WRITE;

	}