@@ -19,6 +19,7 @@ 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
@@ -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
@@ -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;
+}
@@ -700,6 +700,31 @@ 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;
@@ -725,7 +750,9 @@ static int do_sea(unsigned long far, unsigned long esr, struct pt_regs *regs)
*/
siaddr = untagged_addr(far);
}
- arm64_notify_die(inf->name, regs, inf->sig, inf->code, siaddr, esr);
+
+ 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;
}
During the processing of arm64 kernel hardware memory errors(do_sea()), if the errors is consumed in 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, kill the user process and isolate the user page with hardware memory errors is a better choice. This patch only enable machine error check framework, it add exception fixup before kernel panic in do_sea() and only limit the consumption of hardware memory errors in kernel mode triggered by user mode processes. If fixup successful, panic can be avoided. Signed-off-by: Tong Tiangen <tongtiangen@huawei.com> --- arch/arm64/Kconfig | 1 + arch/arm64/include/asm/extable.h | 1 + arch/arm64/mm/extable.c | 16 ++++++++++++++++ arch/arm64/mm/fault.c | 29 ++++++++++++++++++++++++++++- 4 files changed, 46 insertions(+), 1 deletion(-)