diff mbox

[PATCHv4,1/7] arm64: Treat handle_arch_irq as a function pointer

Message ID 1414440752-9411-2-git-send-email-lauraa@codeaurora.org (mailing list archive)
State New, archived
Headers show

Commit Message

Laura Abbott Oct. 27, 2014, 8:12 p.m. UTC
handle_arch_irq isn't actually text, it's just a function pointer.
It doesn't need to be stored in the text section and doing so
causes problems if we ever want to make the kernel text read only.
Declare handle_arch_irq as a proper function pointer stored in
the data section.

Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
---
v4: style comments
---
 arch/arm64/include/asm/irq.h | 1 -
 arch/arm64/kernel/entry.S    | 6 ++----
 arch/arm64/kernel/irq.c      | 2 ++
 3 files changed, 4 insertions(+), 5 deletions(-)

Comments

Ard Biesheuvel Oct. 28, 2014, 8:11 a.m. UTC | #1
On 27 October 2014 21:12, Laura Abbott <lauraa@codeaurora.org> wrote:
> handle_arch_irq isn't actually text, it's just a function pointer.
> It doesn't need to be stored in the text section and doing so
> causes problems if we ever want to make the kernel text read only.
> Declare handle_arch_irq as a proper function pointer stored in
> the data section.
>
> Reviewed-by: Kees Cook <keescook@chromium.org>
> Signed-off-by: Laura Abbott <lauraa@codeaurora.org>

Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

> ---
> v4: style comments
> ---
>  arch/arm64/include/asm/irq.h | 1 -
>  arch/arm64/kernel/entry.S    | 6 ++----
>  arch/arm64/kernel/irq.c      | 2 ++
>  3 files changed, 4 insertions(+), 5 deletions(-)
>
> diff --git a/arch/arm64/include/asm/irq.h b/arch/arm64/include/asm/irq.h
> index e1f7ecd..1eebf5b 100644
> --- a/arch/arm64/include/asm/irq.h
> +++ b/arch/arm64/include/asm/irq.h
> @@ -3,7 +3,6 @@
>
>  #include <asm-generic/irq.h>
>
> -extern void (*handle_arch_irq)(struct pt_regs *);
>  extern void migrate_irqs(void);
>  extern void set_handle_irq(void (*handle_irq)(struct pt_regs *));
>
> diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
> index 726b910..ee27f39 100644
> --- a/arch/arm64/kernel/entry.S
> +++ b/arch/arm64/kernel/entry.S
> @@ -168,7 +168,8 @@ tsk .req    x28             // current thread_info
>   * Interrupt handling.
>   */
>         .macro  irq_handler
> -       ldr     x1, handle_arch_irq
> +       adrp    x1, handle_arch_irq
> +       ldr     x1, [x1, #:lo12:handle_arch_irq]
>         mov     x0, sp
>         blr     x1
>         .endm
> @@ -695,6 +696,3 @@ ENTRY(sys_rt_sigreturn_wrapper)
>         mov     x0, sp
>         b       sys_rt_sigreturn
>  ENDPROC(sys_rt_sigreturn_wrapper)
> -
> -ENTRY(handle_arch_irq)
> -       .quad   0
> diff --git a/arch/arm64/kernel/irq.c b/arch/arm64/kernel/irq.c
> index 071a6ec..240b75c 100644
> --- a/arch/arm64/kernel/irq.c
> +++ b/arch/arm64/kernel/irq.c
> @@ -40,6 +40,8 @@ int arch_show_interrupts(struct seq_file *p, int prec)
>         return 0;
>  }
>
> +void (*handle_arch_irq)(struct pt_regs *) = NULL;
> +
>  void __init set_handle_irq(void (*handle_irq)(struct pt_regs *))
>  {
>         if (handle_arch_irq)
> --
> Qualcomm Innovation Center, Inc.
> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
Mark Rutland Oct. 28, 2014, 10:25 a.m. UTC | #2
On Mon, Oct 27, 2014 at 08:12:26PM +0000, Laura Abbott wrote:
> handle_arch_irq isn't actually text, it's just a function pointer.
> It doesn't need to be stored in the text section and doing so
> causes problems if we ever want to make the kernel text read only.
> Declare handle_arch_irq as a proper function pointer stored in
> the data section.
> 
> Reviewed-by: Kees Cook <keescook@chromium.org>
> Signed-off-by: Laura Abbott <lauraa@codeaurora.org>

This looks good to me, compiles cleanly on v3.18-rc2, and my Juno
continues to boot, so:

Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>

Mark.

> ---
> v4: style comments
> ---
>  arch/arm64/include/asm/irq.h | 1 -
>  arch/arm64/kernel/entry.S    | 6 ++----
>  arch/arm64/kernel/irq.c      | 2 ++
>  3 files changed, 4 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/arm64/include/asm/irq.h b/arch/arm64/include/asm/irq.h
> index e1f7ecd..1eebf5b 100644
> --- a/arch/arm64/include/asm/irq.h
> +++ b/arch/arm64/include/asm/irq.h
> @@ -3,7 +3,6 @@
>  
>  #include <asm-generic/irq.h>
>  
> -extern void (*handle_arch_irq)(struct pt_regs *);
>  extern void migrate_irqs(void);
>  extern void set_handle_irq(void (*handle_irq)(struct pt_regs *));
>  
> diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
> index 726b910..ee27f39 100644
> --- a/arch/arm64/kernel/entry.S
> +++ b/arch/arm64/kernel/entry.S
> @@ -168,7 +168,8 @@ tsk	.req	x28		// current thread_info
>   * Interrupt handling.
>   */
>  	.macro	irq_handler
> -	ldr	x1, handle_arch_irq
> +	adrp	x1, handle_arch_irq
> +	ldr	x1, [x1, #:lo12:handle_arch_irq]
>  	mov	x0, sp
>  	blr	x1
>  	.endm
> @@ -695,6 +696,3 @@ ENTRY(sys_rt_sigreturn_wrapper)
>  	mov	x0, sp
>  	b	sys_rt_sigreturn
>  ENDPROC(sys_rt_sigreturn_wrapper)
> -
> -ENTRY(handle_arch_irq)
> -	.quad	0
> diff --git a/arch/arm64/kernel/irq.c b/arch/arm64/kernel/irq.c
> index 071a6ec..240b75c 100644
> --- a/arch/arm64/kernel/irq.c
> +++ b/arch/arm64/kernel/irq.c
> @@ -40,6 +40,8 @@ int arch_show_interrupts(struct seq_file *p, int prec)
>  	return 0;
>  }
>  
> +void (*handle_arch_irq)(struct pt_regs *) = NULL;
> +
>  void __init set_handle_irq(void (*handle_irq)(struct pt_regs *))
>  {
>  	if (handle_arch_irq)
> -- 
> Qualcomm Innovation Center, Inc.
> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project
> 
>
diff mbox

Patch

diff --git a/arch/arm64/include/asm/irq.h b/arch/arm64/include/asm/irq.h
index e1f7ecd..1eebf5b 100644
--- a/arch/arm64/include/asm/irq.h
+++ b/arch/arm64/include/asm/irq.h
@@ -3,7 +3,6 @@ 
 
 #include <asm-generic/irq.h>
 
-extern void (*handle_arch_irq)(struct pt_regs *);
 extern void migrate_irqs(void);
 extern void set_handle_irq(void (*handle_irq)(struct pt_regs *));
 
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 726b910..ee27f39 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -168,7 +168,8 @@  tsk	.req	x28		// current thread_info
  * Interrupt handling.
  */
 	.macro	irq_handler
-	ldr	x1, handle_arch_irq
+	adrp	x1, handle_arch_irq
+	ldr	x1, [x1, #:lo12:handle_arch_irq]
 	mov	x0, sp
 	blr	x1
 	.endm
@@ -695,6 +696,3 @@  ENTRY(sys_rt_sigreturn_wrapper)
 	mov	x0, sp
 	b	sys_rt_sigreturn
 ENDPROC(sys_rt_sigreturn_wrapper)
-
-ENTRY(handle_arch_irq)
-	.quad	0
diff --git a/arch/arm64/kernel/irq.c b/arch/arm64/kernel/irq.c
index 071a6ec..240b75c 100644
--- a/arch/arm64/kernel/irq.c
+++ b/arch/arm64/kernel/irq.c
@@ -40,6 +40,8 @@  int arch_show_interrupts(struct seq_file *p, int prec)
 	return 0;
 }
 
+void (*handle_arch_irq)(struct pt_regs *) = NULL;
+
 void __init set_handle_irq(void (*handle_irq)(struct pt_regs *))
 {
 	if (handle_arch_irq)