ARM: 9384/2: mm: Make tlbflush routines CFI safe
Instead of avoiding CFI entirely on the TLB flush helpers, reorganize
the code so that the CFI machinery can deal with it. The important
things to take into account are:
- functions in asm called indirectly from C need to be defined using
SYM_TYPED_FUNC_START()
- a reference to the asm function needs to be visible to the compiler,
in order to get it to emit the typeid symbol.
The latter means that defining the cpu_tlb_fns structs is best done from
C code, so that the references in the static initializers will be
visible to the compiler.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
diff --git a/arch/arm/mm/tlb-fa.S b/arch/arm/mm/tlb-fa.S
index def6161..85a6fe7 100644
--- a/arch/arm/mm/tlb-fa.S
+++ b/arch/arm/mm/tlb-fa.S
@@ -15,6 +15,7 @@
*/
#include <linux/linkage.h>
#include <linux/init.h>
+#include <linux/cfi_types.h>
#include <asm/assembler.h>
#include <asm/asm-offsets.h>
#include <asm/tlbflush.h>
@@ -31,7 +32,7 @@
* - mm - mm_struct describing address space
*/
.align 4
-ENTRY(fa_flush_user_tlb_range)
+SYM_TYPED_FUNC_START(fa_flush_user_tlb_range)
vma_vm_mm ip, r2
act_mm r3 @ get current->active_mm
eors r3, ip, r3 @ == mm ?
@@ -46,9 +47,10 @@
blo 1b
mcr p15, 0, r3, c7, c10, 4 @ data write barrier
ret lr
+SYM_FUNC_END(fa_flush_user_tlb_range)
-ENTRY(fa_flush_kern_tlb_range)
+SYM_TYPED_FUNC_START(fa_flush_kern_tlb_range)
mov r3, #0
mcr p15, 0, r3, c7, c10, 4 @ drain WB
bic r0, r0, #0x0ff
@@ -60,8 +62,4 @@
mcr p15, 0, r3, c7, c10, 4 @ data write barrier
mcr p15, 0, r3, c7, c5, 4 @ prefetch flush (isb)
ret lr
-
- __INITDATA
-
- /* define struct cpu_tlb_fns (see <asm/tlbflush.h> and proc-macros.S) */
- define_tlb_functions fa, fa_tlb_flags
+SYM_FUNC_END(fa_flush_kern_tlb_range)
