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* [PATCH] arm64: scs: Drop unused 'tmp' argument to scs_{load, save} asm macros
@ 2021-05-27 10:55 Will Deacon
  2021-05-27 11:03 ` [PATCH] arm64: scs: Drop unused 'tmp' argument to scs_{load,save} " Mark Rutland
  2021-05-27 15:08 ` [PATCH] arm64: scs: Drop unused 'tmp' argument to scs_{load, save} " Sami Tolvanen
  0 siblings, 2 replies; 3+ messages in thread
From: Will Deacon @ 2021-05-27 10:55 UTC (permalink / raw)
  To: linux-arm-kernel; +Cc: kernel-team, Will Deacon, Sami Tolvanen, Mark Rutland

The scs_load and scs_save asm macros don't make use of the mandatory
'tmp' register argument, so drop it and fix up the callers.

Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
---

Applies against for-next/boot

 arch/arm64/include/asm/scs.h | 8 ++++----
 arch/arm64/kernel/entry.S    | 8 ++++----
 arch/arm64/kernel/head.S     | 2 +-
 3 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/arch/arm64/include/asm/scs.h b/arch/arm64/include/asm/scs.h
index eaa2cd92e4c1..8297bccf0784 100644
--- a/arch/arm64/include/asm/scs.h
+++ b/arch/arm64/include/asm/scs.h
@@ -9,18 +9,18 @@
 #ifdef CONFIG_SHADOW_CALL_STACK
 	scs_sp	.req	x18
 
-	.macro scs_load tsk, tmp
+	.macro scs_load tsk
 	ldr	scs_sp, [\tsk, #TSK_TI_SCS_SP]
 	.endm
 
-	.macro scs_save tsk, tmp
+	.macro scs_save tsk
 	str	scs_sp, [\tsk, #TSK_TI_SCS_SP]
 	.endm
 #else
-	.macro scs_load tsk, tmp
+	.macro scs_load tsk
 	.endm
 
-	.macro scs_save tsk, tmp
+	.macro scs_save tsk
 	.endm
 #endif /* CONFIG_SHADOW_CALL_STACK */
 
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 294f24e16fee..3153f1448cdb 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -275,7 +275,7 @@ alternative_else_nop_endif
 
 	mte_set_kernel_gcr x22, x23
 
-	scs_load tsk, x20
+	scs_load tsk
 	.else
 	add	x21, sp, #PT_REGS_SIZE
 	get_current_task tsk
@@ -375,7 +375,7 @@ alternative_if ARM64_WORKAROUND_845719
 alternative_else_nop_endif
 #endif
 3:
-	scs_save tsk, x0
+	scs_save tsk
 
 #ifdef CONFIG_ARM64_PTR_AUTH
 alternative_if ARM64_HAS_ADDRESS_AUTH
@@ -979,8 +979,8 @@ SYM_FUNC_START(cpu_switch_to)
 	mov	sp, x9
 	msr	sp_el0, x1
 	ptrauth_keys_install_kernel x1, x8, x9, x10
-	scs_save x0, x8
-	scs_load x1, x8
+	scs_save x0
+	scs_load x1
 	ret
 SYM_FUNC_END(cpu_switch_to)
 NOKPROBE(cpu_switch_to)
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 070ed53c049d..6a700526b117 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -412,7 +412,7 @@ SYM_FUNC_END(__create_page_tables)
 	stp	xzr, xzr, [sp, #S_STACKFRAME]
 	add	x29, sp, #S_STACKFRAME
 
-	scs_load \tsk, \tmp1
+	scs_load \tsk
 
 	adr_l	\tmp1, __per_cpu_offset
 	ldr	w\tmp2, [\tsk, #TSK_CPU]
-- 
2.31.1.818.g46aad6cb9e-goog


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^ permalink raw reply related	[flat|nested] 3+ messages in thread

* Re: [PATCH] arm64: scs: Drop unused 'tmp' argument to scs_{load,save} asm macros
  2021-05-27 10:55 [PATCH] arm64: scs: Drop unused 'tmp' argument to scs_{load, save} asm macros Will Deacon
@ 2021-05-27 11:03 ` Mark Rutland
  2021-05-27 15:08 ` [PATCH] arm64: scs: Drop unused 'tmp' argument to scs_{load, save} " Sami Tolvanen
  1 sibling, 0 replies; 3+ messages in thread
From: Mark Rutland @ 2021-05-27 11:03 UTC (permalink / raw)
  To: Will Deacon; +Cc: linux-arm-kernel, kernel-team, Sami Tolvanen

On Thu, May 27, 2021 at 11:55:29AM +0100, Will Deacon wrote:
> The scs_load and scs_save asm macros don't make use of the mandatory
> 'tmp' register argument, so drop it and fix up the callers.
> 
> Cc: Sami Tolvanen <samitolvanen@google.com>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Signed-off-by: Will Deacon <will@kernel.org>

I see this has been the case since commit:

  51189c7a7ed1b4ed ("arm64: scs: Store absolute SCS stack pointer value in thread_info")

... so this looks good to me:

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

Mark.

> ---
> 
> Applies against for-next/boot
> 
>  arch/arm64/include/asm/scs.h | 8 ++++----
>  arch/arm64/kernel/entry.S    | 8 ++++----
>  arch/arm64/kernel/head.S     | 2 +-
>  3 files changed, 9 insertions(+), 9 deletions(-)
> 
> diff --git a/arch/arm64/include/asm/scs.h b/arch/arm64/include/asm/scs.h
> index eaa2cd92e4c1..8297bccf0784 100644
> --- a/arch/arm64/include/asm/scs.h
> +++ b/arch/arm64/include/asm/scs.h
> @@ -9,18 +9,18 @@
>  #ifdef CONFIG_SHADOW_CALL_STACK
>  	scs_sp	.req	x18
>  
> -	.macro scs_load tsk, tmp
> +	.macro scs_load tsk
>  	ldr	scs_sp, [\tsk, #TSK_TI_SCS_SP]
>  	.endm
>  
> -	.macro scs_save tsk, tmp
> +	.macro scs_save tsk
>  	str	scs_sp, [\tsk, #TSK_TI_SCS_SP]
>  	.endm
>  #else
> -	.macro scs_load tsk, tmp
> +	.macro scs_load tsk
>  	.endm
>  
> -	.macro scs_save tsk, tmp
> +	.macro scs_save tsk
>  	.endm
>  #endif /* CONFIG_SHADOW_CALL_STACK */
>  
> diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
> index 294f24e16fee..3153f1448cdb 100644
> --- a/arch/arm64/kernel/entry.S
> +++ b/arch/arm64/kernel/entry.S
> @@ -275,7 +275,7 @@ alternative_else_nop_endif
>  
>  	mte_set_kernel_gcr x22, x23
>  
> -	scs_load tsk, x20
> +	scs_load tsk
>  	.else
>  	add	x21, sp, #PT_REGS_SIZE
>  	get_current_task tsk
> @@ -375,7 +375,7 @@ alternative_if ARM64_WORKAROUND_845719
>  alternative_else_nop_endif
>  #endif
>  3:
> -	scs_save tsk, x0
> +	scs_save tsk
>  
>  #ifdef CONFIG_ARM64_PTR_AUTH
>  alternative_if ARM64_HAS_ADDRESS_AUTH
> @@ -979,8 +979,8 @@ SYM_FUNC_START(cpu_switch_to)
>  	mov	sp, x9
>  	msr	sp_el0, x1
>  	ptrauth_keys_install_kernel x1, x8, x9, x10
> -	scs_save x0, x8
> -	scs_load x1, x8
> +	scs_save x0
> +	scs_load x1
>  	ret
>  SYM_FUNC_END(cpu_switch_to)
>  NOKPROBE(cpu_switch_to)
> diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
> index 070ed53c049d..6a700526b117 100644
> --- a/arch/arm64/kernel/head.S
> +++ b/arch/arm64/kernel/head.S
> @@ -412,7 +412,7 @@ SYM_FUNC_END(__create_page_tables)
>  	stp	xzr, xzr, [sp, #S_STACKFRAME]
>  	add	x29, sp, #S_STACKFRAME
>  
> -	scs_load \tsk, \tmp1
> +	scs_load \tsk
>  
>  	adr_l	\tmp1, __per_cpu_offset
>  	ldr	w\tmp2, [\tsk, #TSK_CPU]
> -- 
> 2.31.1.818.g46aad6cb9e-goog
> 

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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] arm64: scs: Drop unused 'tmp' argument to scs_{load, save} asm macros
  2021-05-27 10:55 [PATCH] arm64: scs: Drop unused 'tmp' argument to scs_{load, save} asm macros Will Deacon
  2021-05-27 11:03 ` [PATCH] arm64: scs: Drop unused 'tmp' argument to scs_{load,save} " Mark Rutland
@ 2021-05-27 15:08 ` Sami Tolvanen
  1 sibling, 0 replies; 3+ messages in thread
From: Sami Tolvanen @ 2021-05-27 15:08 UTC (permalink / raw)
  To: Will Deacon; +Cc: linux-arm-kernel, Android Kernel Team, Mark Rutland

Hi Will,

On Thu, May 27, 2021 at 3:55 AM Will Deacon <will@kernel.org> wrote:
>
> The scs_load and scs_save asm macros don't make use of the mandatory
> 'tmp' register argument, so drop it and fix up the callers.
>
> Cc: Sami Tolvanen <samitolvanen@google.com>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Signed-off-by: Will Deacon <will@kernel.org>
> ---
>
> Applies against for-next/boot
>
>  arch/arm64/include/asm/scs.h | 8 ++++----
>  arch/arm64/kernel/entry.S    | 8 ++++----
>  arch/arm64/kernel/head.S     | 2 +-
>  3 files changed, 9 insertions(+), 9 deletions(-)
>
> diff --git a/arch/arm64/include/asm/scs.h b/arch/arm64/include/asm/scs.h
> index eaa2cd92e4c1..8297bccf0784 100644
> --- a/arch/arm64/include/asm/scs.h
> +++ b/arch/arm64/include/asm/scs.h
> @@ -9,18 +9,18 @@
>  #ifdef CONFIG_SHADOW_CALL_STACK
>         scs_sp  .req    x18
>
> -       .macro scs_load tsk, tmp
> +       .macro scs_load tsk
>         ldr     scs_sp, [\tsk, #TSK_TI_SCS_SP]
>         .endm
>
> -       .macro scs_save tsk, tmp
> +       .macro scs_save tsk
>         str     scs_sp, [\tsk, #TSK_TI_SCS_SP]
>         .endm
>  #else
> -       .macro scs_load tsk, tmp
> +       .macro scs_load tsk
>         .endm
>
> -       .macro scs_save tsk, tmp
> +       .macro scs_save tsk
>         .endm
>  #endif /* CONFIG_SHADOW_CALL_STACK */
>
> diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
> index 294f24e16fee..3153f1448cdb 100644
> --- a/arch/arm64/kernel/entry.S
> +++ b/arch/arm64/kernel/entry.S
> @@ -275,7 +275,7 @@ alternative_else_nop_endif
>
>         mte_set_kernel_gcr x22, x23
>
> -       scs_load tsk, x20
> +       scs_load tsk
>         .else
>         add     x21, sp, #PT_REGS_SIZE
>         get_current_task tsk
> @@ -375,7 +375,7 @@ alternative_if ARM64_WORKAROUND_845719
>  alternative_else_nop_endif
>  #endif
>  3:
> -       scs_save tsk, x0
> +       scs_save tsk
>
>  #ifdef CONFIG_ARM64_PTR_AUTH
>  alternative_if ARM64_HAS_ADDRESS_AUTH
> @@ -979,8 +979,8 @@ SYM_FUNC_START(cpu_switch_to)
>         mov     sp, x9
>         msr     sp_el0, x1
>         ptrauth_keys_install_kernel x1, x8, x9, x10
> -       scs_save x0, x8
> -       scs_load x1, x8
> +       scs_save x0
> +       scs_load x1
>         ret
>  SYM_FUNC_END(cpu_switch_to)
>  NOKPROBE(cpu_switch_to)
> diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
> index 070ed53c049d..6a700526b117 100644
> --- a/arch/arm64/kernel/head.S
> +++ b/arch/arm64/kernel/head.S
> @@ -412,7 +412,7 @@ SYM_FUNC_END(__create_page_tables)
>         stp     xzr, xzr, [sp, #S_STACKFRAME]
>         add     x29, sp, #S_STACKFRAME
>
> -       scs_load \tsk, \tmp1
> +       scs_load \tsk
>
>         adr_l   \tmp1, __per_cpu_offset
>         ldr     w\tmp2, [\tsk, #TSK_CPU]

Looks good to me, thanks for cleaning this up!

Reviewed-by: Sami Tolvanen <samitolvanen@google.com>

Sami

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^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2021-05-27 16:35 UTC | newest]

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2021-05-27 10:55 [PATCH] arm64: scs: Drop unused 'tmp' argument to scs_{load, save} asm macros Will Deacon
2021-05-27 11:03 ` [PATCH] arm64: scs: Drop unused 'tmp' argument to scs_{load,save} " Mark Rutland
2021-05-27 15:08 ` [PATCH] arm64: scs: Drop unused 'tmp' argument to scs_{load, save} " Sami Tolvanen

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