Commit 975e216e authored by Tong Tiangen's avatar Tong Tiangen
Browse files

arm64: add support for machine check error safe 

hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I8M74H


CVE: NA

-------------------------------

For the arm64 kernel, when it processes hardware memory errors for
synchronize notifications(do_sea()), if the errors is consumed within the
kernel, the current processing is panic. However, it is not optimal.

Take uaccess for example, if the uaccess operation fails due to memory
error, only the user process will be affected. Killing the user process and
isolating the corrupt page is a better choice.

This patch only enable machine error check framework and adds an exception
fixup before the kernel panic in do_sea().

Signed-off-by: default avatarTong Tiangen <tongtiangen@huawei.com>
parent 59feaaa0

arch/arm64/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ config ARM64 
	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2

	select ARCH_ENABLE_THP_MIGRATION if TRANSPARENT_HUGEPAGE

	select ARCH_HAS_CACHE_LINE_SIZE

	select ARCH_HAS_COPY_MC if ACPI_APEI_GHES

	select ARCH_HAS_CURRENT_STACK_POINTER

	select ARCH_HAS_DEBUG_VIRTUAL

	select ARCH_HAS_DEBUG_VM_PGTABLE

arch/arm64/include/asm/extable.h

+1 −0
Original line number Diff line number Diff line
@@ -46,4 +46,5 @@ bool ex_handler_bpf(const struct exception_table_entry *ex, 
#endif /* !CONFIG_BPF_JIT */



bool fixup_exception(struct pt_regs *regs);

bool fixup_exception_mc(struct pt_regs *regs);

#endif

arch/arm64/mm/extable.c

+16 −0
Original line number Diff line number Diff line
@@ -76,3 +76,19 @@ bool fixup_exception(struct pt_regs *regs) 


	BUG();

}



bool fixup_exception_mc(struct pt_regs *regs)

{

	const struct exception_table_entry *ex;



	ex = search_exception_tables(instruction_pointer(regs));

	if (!ex)

		return false;



	/*

	 * This is not complete, More Machine check safe extable type can

	 * be processed here.

	 */



	return false;

}

arch/arm64/mm/fault.c

+28 −1
Original line number Diff line number Diff line
@@ -728,6 +728,31 @@ static int do_bad(unsigned long far, unsigned long esr, struct pt_regs *regs) 
	return 1; /* "fault" */

}



static bool arm64_do_kernel_sea(unsigned long addr, unsigned int esr,

				     struct pt_regs *regs, int sig, int code)

{

	if (!IS_ENABLED(CONFIG_ARCH_HAS_COPY_MC))

		return false;



	if (user_mode(regs))

		return false;



	if (apei_claim_sea(regs) < 0)

		return false;



	if (!fixup_exception_mc(regs))

		return false;



	if (current->flags & PF_KTHREAD)

		return true;



	set_thread_esr(0, esr);

	arm64_force_sig_fault(sig, code, addr,

		"Uncorrected memory error on access to user memory\n");



	return true;

}



static int do_sea(unsigned long far, unsigned long esr, struct pt_regs *regs)

{

	const struct fault_info *inf;
@@ -753,6 +778,8 @@ static int do_sea(unsigned long far, unsigned long esr, struct pt_regs *regs) 
		 */

		siaddr  = untagged_addr(far);

	}



	if (!arm64_do_kernel_sea(siaddr, esr, regs, inf->sig, inf->code))

		arm64_notify_die(inf->name, regs, inf->sig, inf->code, siaddr, esr);



	return 0;