Commit 6b0ef279 authored by Ard Biesheuvel's avatar Ard Biesheuvel Committed by Russell King (Oracle)
Browse files

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: default avatarArd Biesheuvel <ardb@kernel.org>
Tested-by: default avatarKees Cook <keescook@chromium.org>
Reviewed-by: default avatarSami Tolvanen <samitolvanen@google.com>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: default avatarRussell King (Oracle) <rmk+kernel@armlinux.org.uk>
parent 4cece764

arch/arm/mm/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -62,6 +62,7 @@ obj-$(CONFIG_CPU_TLB_FEROCEON) += tlb-v4wbi.o # reuse v4wbi TLB functions 
obj-$(CONFIG_CPU_TLB_V6)	+= tlb-v6.o

obj-$(CONFIG_CPU_TLB_V7)	+= tlb-v7.o

obj-$(CONFIG_CPU_TLB_FA)	+= tlb-fa.o

obj-y				+= tlb.o



obj-$(CONFIG_CPU_ARM7TDMI)	+= proc-arm7tdmi.o

obj-$(CONFIG_CPU_ARM720T)	+= proc-arm720.o

arch/arm/mm/proc-macros.S

+0 −15
Original line number Diff line number Diff line
@@ -338,21 +338,6 @@ ENTRY(\name\()_cache_fns) 
	.size	\name\()_cache_fns, . - \name\()_cache_fns

.endm



.macro define_tlb_functions name:req, flags_up:req, flags_smp

	.type	\name\()_tlb_fns, #object

	.align 2

ENTRY(\name\()_tlb_fns)

	.long	\name\()_flush_user_tlb_range

	.long	\name\()_flush_kern_tlb_range

	.ifnb \flags_smp

		ALT_SMP(.long	\flags_smp )

		ALT_UP(.long	\flags_up )

	.else

		.long	\flags_up

	.endif

	.size	\name\()_tlb_fns, . - \name\()_tlb_fns

.endm



.macro globl_equ x, y

	.globl	\x

	.equ	\x, \y

arch/arm/mm/tlb-fa.S

+5 −7
Original line number Diff line number Diff line
@@ -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 @@ ENTRY(fa_flush_user_tlb_range) 
	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 @@ ENTRY(fa_flush_kern_tlb_range) 
	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)

arch/arm/mm/tlb-v4.S

+9 −6
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 
 */

#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>
@@ -27,7 +28,7 @@ 
 *	- mm    - mm_struct describing address space

 */

	.align	5

ENTRY(v4_flush_user_tlb_range)

SYM_TYPED_FUNC_START(v4_flush_user_tlb_range)

	vma_vm_mm ip, r2

	act_mm	r3				@ get current->active_mm

	eors	r3, ip, r3				@ == mm ?
@@ -40,6 +41,7 @@ ENTRY(v4_flush_user_tlb_range) 
	cmp	r0, r1

	blo	1b

	ret	lr

SYM_FUNC_END(v4_flush_user_tlb_range)



/*

 *	v4_flush_kern_tlb_range(start, end)
@@ -50,10 +52,11 @@ ENTRY(v4_flush_user_tlb_range) 
 *	- start - virtual address (may not be aligned)

 *	- end   - virtual address (may not be aligned)

 */

#ifdef CONFIG_CFI_CLANG

SYM_TYPED_FUNC_START(v4_flush_kern_tlb_range)

	b	.v4_flush_kern_tlb_range

SYM_FUNC_END(v4_flush_kern_tlb_range)

#else

.globl v4_flush_kern_tlb_range

.equ v4_flush_kern_tlb_range, .v4_flush_kern_tlb_range



	__INITDATA



	/* define struct cpu_tlb_fns (see <asm/tlbflush.h> and proc-macros.S) */

	define_tlb_functions v4, v4_tlb_flags
 
#endif

arch/arm/mm/tlb-v4wb.S

+5 −7
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 
 */

#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>
@@ -27,7 +28,7 @@ 
 *	- mm    - mm_struct describing address space

 */

	.align	5

ENTRY(v4wb_flush_user_tlb_range)

SYM_TYPED_FUNC_START(v4wb_flush_user_tlb_range)

	vma_vm_mm ip, r2

	act_mm	r3				@ get current->active_mm

	eors	r3, ip, r3				@ == mm ?
@@ -43,6 +44,7 @@ ENTRY(v4wb_flush_user_tlb_range) 
	cmp	r0, r1

	blo	1b

	ret	lr

SYM_FUNC_END(v4wb_flush_user_tlb_range)



/*

 *	v4_flush_kern_tlb_range(start, end)
@@ -53,7 +55,7 @@ ENTRY(v4wb_flush_user_tlb_range) 
 *	- start - virtual address (may not be aligned)

 *	- end   - virtual address (may not be aligned)

 */

ENTRY(v4wb_flush_kern_tlb_range)

SYM_TYPED_FUNC_START(v4wb_flush_kern_tlb_range)

	mov	r3, #0

	mcr	p15, 0, r3, c7, c10, 4		@ drain WB

	bic	r0, r0, #0x0ff
@@ -64,8 +66,4 @@ ENTRY(v4wb_flush_kern_tlb_range) 
	cmp	r0, r1

	blo	1b

	ret	lr



	__INITDATA



	/* define struct cpu_tlb_fns (see <asm/tlbflush.h> and proc-macros.S) */

	define_tlb_functions v4wb, v4wb_tlb_flags
 
SYM_FUNC_END(v4wb_flush_kern_tlb_range)