parisc: Add KFENCE support

Signed-off-by: Helge Deller <deller@gmx.de>

diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig
index aee25beb2d00216c954bb29cde6c3f7122273ef9..906187a412ec27b6cb2425dad5a0e111e66366f3 100644 (file)
--- a/arch/parisc/Kconfig
+++ b/arch/parisc/Kconfig
@@ -48,6 +48,7 @@ config PARISC
        select HAVE_ARCH_HASH
        select HAVE_ARCH_JUMP_LABEL
        select HAVE_ARCH_JUMP_LABEL_RELATIVE
+       select HAVE_ARCH_KFENCE
        select HAVE_ARCH_SECCOMP_FILTER
        select HAVE_ARCH_TRACEHOOK
        select HAVE_REGS_AND_STACK_ACCESS_API
@@ -254,11 +255,11 @@ config PARISC_PAGE_SIZE_4KB
 
 config PARISC_PAGE_SIZE_16KB
        bool "16KB"
-       depends on PA8X00 && BROKEN
+       depends on PA8X00 && BROKEN && !KFENCE
 
 config PARISC_PAGE_SIZE_64KB
        bool "64KB"
-       depends on PA8X00 && BROKEN
+       depends on PA8X00 && BROKEN && !KFENCE
 
 endchoice
 

diff --git a/arch/parisc/include/asm/kfence.h b/arch/parisc/include/asm/kfence.h
new file mode 100644 (file)
index 0000000..6259e5a
--- /dev/null
+++ b/arch/parisc/include/asm/kfence.h
@@ -0,0 +1,44 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * PA-RISC KFENCE support.
+ *
+ * Copyright (C) 2021, Helge Deller <deller@gmx.de>
+ */
+
+#ifndef _ASM_PARISC_KFENCE_H
+#define _ASM_PARISC_KFENCE_H
+
+#include <linux/kfence.h>
+
+#include <asm/pgtable.h>
+#include <asm/tlbflush.h>
+
+static inline bool arch_kfence_init_pool(void)
+{
+       return true;
+}
+
+/* Protect the given page and flush TLB. */
+static inline bool kfence_protect_page(unsigned long addr, bool protect)
+{
+       pte_t *pte = virt_to_kpte(addr);
+
+       if (WARN_ON(!pte))
+               return false;
+
+       /*
+        * We need to avoid IPIs, as we may get KFENCE allocations or faults
+        * with interrupts disabled.
+        */
+
+       if (protect)
+               set_pte(pte, __pte(pte_val(*pte) & ~_PAGE_PRESENT));
+       else
+               set_pte(pte, __pte(pte_val(*pte) | _PAGE_PRESENT));
+
+       flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
+
+       return true;
+}
+
+#endif /* _ASM_PARISC_KFENCE_H */

diff --git a/arch/parisc/kernel/traps.c b/arch/parisc/kernel/traps.c
index 747c328fb88627120369aac18f528eb64d3de12b..524781eae4ddef16a623c9e04ee66dc349a1e0c7 100644 (file)
--- a/arch/parisc/kernel/traps.c
+++ b/arch/parisc/kernel/traps.c
@@ -30,6 +30,7 @@
 #include <linux/ratelimit.h>
 #include <linux/uaccess.h>
 #include <linux/kdebug.h>
+#include <linux/kfence.h>
 
 #include <asm/assembly.h>
 #include <asm/io.h>
@@ -787,6 +788,10 @@ void notrace handle_interruption(int code, struct pt_regs *regs)
                /* Clean up and return if in exception table. */
                if (fixup_exception(regs))
                        return;
+               /* Clean up and return if handled by kfence. */
+               if (kfence_handle_page_fault(fault_address,
+                       parisc_acctyp(code, regs->iir) == VM_WRITE, regs))
+                       return;
                pdc_chassis_send_status(PDC_CHASSIS_DIRECT_PANIC);
                parisc_terminate("Kernel Fault", regs, code, fault_address);
            }