linux-kernel - [PATCH RFC v2 19/28] ARM: entry: Remove fast and offset register restore

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Message-Id: <20241029-arm-generic-entry-v2-19-573519abef38@linaro.org>
Date: Tue, 29 Oct 2024 11:52:59 +0100
From: Linus Walleij <linus.walleij@...aro.org>
To: Oleg Nesterov <oleg@...hat.com>, Russell King <linux@...linux.org.uk>, 
 Kees Cook <kees@...nel.org>, Andy Lutomirski <luto@...capital.net>, 
 Will Drewry <wad@...omium.org>, Frederic Weisbecker <frederic@...nel.org>, 
 "Paul E. McKenney" <paulmck@...nel.org>, 
 Jinjie Ruan <ruanjinjie@...wei.com>, Arnd Bergmann <arnd@...db.de>, 
 Ard Biesheuvel <ardb@...nel.org>, Al Viro <viro@...iv.linux.org.uk>
Cc: linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org, 
 Linus Walleij <linus.walleij@...aro.org>
Subject: [PATCH RFC v2 19/28] ARM: entry: Remove fast and offset register
 restore

Now all remaining invocations of restore_user_regs has
fast = 0 and offset = 0 set, so drop these parameters
to the macro.

Signed-off-by: Linus Walleij <linus.walleij@...aro.org>
---
 arch/arm/kernel/entry-armv.S   |  2 +-
 arch/arm/kernel/entry-common.S |  2 +-
 arch/arm/kernel/entry-header.S | 29 +++++++++--------------------
 3 files changed, 11 insertions(+), 22 deletions(-)

diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S
index 09ce1be1f677..bd468d58dc02 100644
--- a/arch/arm/kernel/entry-armv.S
+++ b/arch/arm/kernel/entry-armv.S
@@ -496,7 +496,7 @@ __fiq_usr:
 	mov	r0, sp				@ struct pt_regs *regs
 	bl	handle_fiq_as_nmi
 	get_thread_info tsk
-	restore_user_regs fast = 0, offset = 0
+	restore_user_regs
  UNWIND(.fnend		)
 ENDPROC(__fiq_usr)
 
diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index dddbd6ba1eb9..d27e34d7e97a 100644
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -81,7 +81,7 @@ no_work_pending:
 #ifdef CONFIG_GCC_PLUGIN_STACKLEAK
 	bl	stackleak_erase_on_task_stack
 #endif
-	restore_user_regs fast = 0, offset = 0
+	restore_user_regs
 ENDPROC(ret_to_user_from_irq)
 ENDPROC(ret_to_user)
 
diff --git a/arch/arm/kernel/entry-header.S b/arch/arm/kernel/entry-header.S
index 50c0b55adc74..51c7f93c1ded 100644
--- a/arch/arm/kernel/entry-header.S
+++ b/arch/arm/kernel/entry-header.S
@@ -290,7 +290,7 @@
 	.endm
 
 
-	.macro	restore_user_regs, fast = 0, offset = 0
+	.macro	restore_user_regs
 #if defined(CONFIG_CPU_32v6K) && \
     (!defined(CONFIG_CPU_V6) || defined(CONFIG_SMP))
 #ifdef CONFIG_CPU_V6
@@ -309,8 +309,8 @@ ALT_UP_B(.L1_\@)
 #ifndef CONFIG_THUMB2_KERNEL
 	@ ARM mode restore
 	mov	r2, sp
-	ldr	r1, [r2, #\offset + S_PSR]	@ get calling cpsr
-	ldr	lr, [r2, #\offset + S_PC]!	@ get pc
+	ldr	r1, [r2, S_PSR]			@ get calling cpsr
+	ldr	lr, [r2, S_PC]!			@ get pc
 	tst	r1, #PSR_I_BIT | 0x0f
 	bne	1f
 	msr	spsr_cxsf, r1			@ save in spsr_svc
@@ -318,31 +318,24 @@ ALT_UP_B(.L1_\@)
 	@ We must avoid clrex due to Cortex-A15 erratum #830321
 	strex	r1, r2, [r2]			@ clear the exclusive monitor
 #endif
-	.if	\fast
-	ldmdb	r2, {r1 - lr}^			@ get calling r1 - lr
-	.else
 	ldmdb	r2, {r0 - lr}^			@ get calling r0 - lr
-	.endif
 	mov	r0, r0				@ ARMv5T and earlier require a nop
 						@ after ldm {}^
-	add	sp, sp, #\offset + PT_REGS_SIZE
+	add	sp, sp, #PT_REGS_SIZE
 	movs	pc, lr				@ return & move spsr_svc into cpsr
 1:	bug	"Returning to usermode but unexpected PSR bits set?", \@
 #elif defined(CONFIG_CPU_V7M)
 	@ V7M restore.
 	@ Note that we don't need to do clrex here as clearing the local
 	@ monitor is part of the exception entry and exit sequence.
-	.if	\offset
-	add	sp, #\offset
-	.endif
-	v7m_exception_slow_exit ret_r0 = \fast
+	v7m_exception_slow_exit ret_r0 = 0
 #else
 	@ Thumb mode restore
 	mov	r2, sp
-	load_user_sp_lr r2, r3, \offset + S_SP	@ calling sp, lr
-	ldr	r1, [sp, #\offset + S_PSR]	@ get calling cpsr
-	ldr	lr, [sp, #\offset + S_PC]	@ get pc
-	add	sp, sp, #\offset + S_SP
+	load_user_sp_lr r2, r3, S_SP		@ calling sp, lr
+	ldr	r1, [sp, S_PSR]			@ get calling cpsr
+	ldr	lr, [sp, S_PC]			@ get pc
+	add	sp, sp, S_SP
 	tst	r1, #PSR_I_BIT | 0x0f
 	bne	1f
 	msr	spsr_cxsf, r1			@ save in spsr_svc
@@ -350,11 +343,7 @@ ALT_UP_B(.L1_\@)
 	@ We must avoid clrex due to Cortex-A15 erratum #830321
 	strex	r1, r2, [sp]			@ clear the exclusive monitor
 
-	.if	\fast
-	ldmdb	sp, {r1 - r12}			@ get calling r1 - r12
-	.else
 	ldmdb	sp, {r0 - r12}			@ get calling r0 - r12
-	.endif
 	add	sp, sp, #PT_REGS_SIZE - S_SP
 	movs	pc, lr				@ return & move spsr_svc into cpsr
 1:	bug	"Returning to usermode but unexpected PSR bits set?", \@

-- 
2.46.2