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From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	npiggin@gmail.com, msuchanek@suse.de
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: [PATCH v4 03/23] powerpc/32: On syscall entry, enable instruction translation at the same time as data
Date: Mon, 25 Jan 2021 14:48:15 +0000 (UTC)	[thread overview]
Message-ID: <2dc1a491c32be486d96a0ed6f8979025c17bbb23.1611585031.git.christophe.leroy@csgroup.eu> (raw)
In-Reply-To: <cover.1611585031.git.christophe.leroy@csgroup.eu>

On 40x and 8xx, kernel text is pinned.
On book3s/32, kernel text is mapped by BATs.

Enable instruction translation at the same time as data translation, it
makes things simpler.

MSR_RI can also be set at the same time because srr0/srr1 are already
saved and r1 is set properly.

On booke, translation is always on, so at the end all PPC32
have translation on early.

This reduces null_syscall benchmark by 13 cycles on 8xx
(296 ==> 283 cycles).

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 arch/powerpc/kernel/head_32.h    | 26 +++++++++-----------------
 arch/powerpc/kernel/head_booke.h |  7 ++-----
 2 files changed, 11 insertions(+), 22 deletions(-)

diff --git a/arch/powerpc/kernel/head_32.h b/arch/powerpc/kernel/head_32.h
index fdc07beab844..4029c51dce5d 100644
--- a/arch/powerpc/kernel/head_32.h
+++ b/arch/powerpc/kernel/head_32.h
@@ -125,9 +125,13 @@
 	lwz	r1,TASK_STACK-THREAD(r12)
 	beq-	99f
 	addi	r1, r1, THREAD_SIZE - INT_FRAME_SIZE
-	LOAD_REG_IMMEDIATE(r10, MSR_KERNEL & ~(MSR_IR | MSR_RI)) /* can take DTLB miss */
-	mtmsr	r10
-	isync
+	LOAD_REG_IMMEDIATE(r10, MSR_KERNEL)		/* can take exceptions */
+	mtspr	SPRN_SRR1, r10
+	lis	r10, 1f@h
+	ori	r10, r10, 1f@l
+	mtspr	SPRN_SRR0, r10
+	rfi
+1:
 	tovirt(r12, r12)
 	stw	r11,GPR1(r1)
 	stw	r11,0(r1)
@@ -141,9 +145,6 @@
 	stw	r10,_CCR(r11)		/* save registers */
 #ifdef CONFIG_40x
 	rlwinm	r9,r9,0,14,12		/* clear MSR_WE (necessary?) */
-#else
-	LOAD_REG_IMMEDIATE(r10, MSR_KERNEL & ~MSR_IR) /* can take exceptions */
-	mtmsr	r10			/* (except for mach check in rtas) */
 #endif
 	lis	r10,STACK_FRAME_REGS_MARKER@ha /* exception frame marker */
 	stw	r2,GPR2(r11)
@@ -180,8 +181,6 @@
 #endif
 
 3:
-	lis	r11, transfer_to_syscall@h
-	ori	r11, r11, transfer_to_syscall@l
 #ifdef CONFIG_TRACE_IRQFLAGS
 	/*
 	 * If MSR is changing we need to keep interrupts disabled at this point
@@ -193,15 +192,8 @@
 #else
 	LOAD_REG_IMMEDIATE(r10, MSR_KERNEL | MSR_EE)
 #endif
-#if defined(CONFIG_PPC_8xx) && defined(CONFIG_PERF_EVENTS)
-	mtspr	SPRN_NRI, r0
-#endif
-	mtspr	SPRN_SRR1,r10
-	mtspr	SPRN_SRR0,r11
-	rfi				/* jump to handler, enable MMU */
-#ifdef CONFIG_40x
-	b .	/* Prevent prefetch past rfi */
-#endif
+	mtmsr	r10
+	b	transfer_to_syscall		/* jump to handler */
 99:	b	ret_from_kernel_syscall
 .endm
 
diff --git a/arch/powerpc/kernel/head_booke.h b/arch/powerpc/kernel/head_booke.h
index 706cd9368992..b3c502c503a0 100644
--- a/arch/powerpc/kernel/head_booke.h
+++ b/arch/powerpc/kernel/head_booke.h
@@ -157,8 +157,6 @@ ALT_FTR_SECTION_END_IFSET(CPU_FTR_EMB_HV)
 	stw	r12,4(r11)
 
 3:
-	lis	r11, transfer_to_syscall@h
-	ori	r11, r11, transfer_to_syscall@l
 #ifdef CONFIG_TRACE_IRQFLAGS
 	/*
 	 * If MSR is changing we need to keep interrupts disabled at this point
@@ -172,9 +170,8 @@ ALT_FTR_SECTION_END_IFSET(CPU_FTR_EMB_HV)
 	lis	r10, (MSR_KERNEL | MSR_EE)@h
 	ori	r10, r10, (MSR_KERNEL | MSR_EE)@l
 #endif
-	mtspr	SPRN_SRR1,r10
-	mtspr	SPRN_SRR0,r11
-	rfi				/* jump to handler, enable MMU */
+	mtmsr	r10
+	b	transfer_to_syscall	/* jump to handler */
 99:	b	ret_from_kernel_syscall
 .endm
 
-- 
2.25.0


  parent reply	other threads:[~2021-01-26  6:44 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-25 14:48 [PATCH v4 00/23] powerpc/32: Implement C syscall entry/exit Christophe Leroy
2021-01-25 14:48 ` [PATCH v4 01/23] powerpc/32s: Add missing call to kuep_lock on syscall entry Christophe Leroy
2021-01-25 14:48 ` [PATCH v4 02/23] powerpc/32: Always enable data translation " Christophe Leroy
2021-01-25 14:48 ` Christophe Leroy [this message]
2021-01-25 14:48 ` [PATCH v4 04/23] powerpc/32: Reorder instructions to avoid using CTR in " Christophe Leroy
2021-01-25 14:48 ` [PATCH v4 05/23] powerpc/64s: Make kuap_check_amr() and kuap_get_and_check_amr() generic Christophe Leroy
2021-01-25 14:48 ` [PATCH v4 06/23] powerpc/32s: Create C version of kuap_user/kernel_restore() and friends Christophe Leroy
2021-01-25 14:48 ` [PATCH v4 07/23] powerpc/8xx: " Christophe Leroy
2021-01-25 14:48 ` [PATCH v4 08/23] powerpc/irq: Add helper to set regs->softe Christophe Leroy
2021-01-25 14:48 ` [PATCH v4 09/23] powerpc/irq: Rework helpers that manipulate MSR[EE/RI] Christophe Leroy
2021-01-25 14:48 ` [PATCH v4 10/23] powerpc/irq: Add stub irq_soft_mask_return() for PPC32 Christophe Leroy
2021-01-25 14:48 ` [PATCH v4 11/23] powerpc/syscall: Rename syscall_64.c into syscall.c Christophe Leroy
2021-01-26 10:21   ` Nicholas Piggin
2021-01-26 10:28     ` David Laight
2021-01-27 23:50       ` Nicholas Piggin
2021-02-02  6:15         ` Christophe Leroy
2021-02-02  6:38           ` Nicholas Piggin
2021-02-02  6:58             ` Christophe Leroy
2021-02-02 20:10             ` Segher Boessenkool
2021-02-08 17:47     ` Christophe Leroy
2021-01-25 14:48 ` [PATCH v4 12/23] powerpc/syscall: Make syscall.c buildable on PPC32 Christophe Leroy
2021-01-25 14:48 ` [PATCH v4 13/23] powerpc/syscall: Use is_compat_task() Christophe Leroy
2021-01-25 14:48 ` [PATCH v4 14/23] powerpc/syscall: Save r3 in regs->orig_r3 Christophe Leroy
2021-01-26 10:18   ` Nicholas Piggin
2021-02-08 17:47     ` Christophe Leroy
2021-01-25 14:48 ` [PATCH v4 15/23] powerpc/syscall: Change condition to check MSR_RI Christophe Leroy
2021-01-25 14:48 ` [PATCH v4 16/23] powerpc/32: Always save non volatile GPRs at syscall entry Christophe Leroy
2021-01-25 14:48 ` [PATCH v4 17/23] powerpc/syscall: implement system call entry/exit logic in C for PPC32 Christophe Leroy
2021-01-25 14:48 ` [PATCH v4 18/23] powerpc/32: Remove verification of MSR_PR on syscall in the ASM entry Christophe Leroy
2021-01-25 14:48 ` [PATCH v4 19/23] powerpc/syscall: Avoid stack frame in likely part of system_call_exception() Christophe Leroy
2021-01-26 10:14   ` Nicholas Piggin
2021-01-25 14:48 ` [PATCH v4 20/23] powerpc/syscall: Do not check unsupported scv vector on PPC32 Christophe Leroy
2021-01-26 10:16   ` Nicholas Piggin
2021-02-08 17:45     ` Christophe Leroy
2021-01-25 14:48 ` [PATCH v4 21/23] powerpc/syscall: Remove FULL_REGS verification in system_call_exception Christophe Leroy
2021-01-25 14:48 ` [PATCH v4 22/23] powerpc/syscall: Optimise checks in beginning of system_call_exception() Christophe Leroy
2021-01-25 14:48 ` [PATCH v4 23/23] powerpc/syscall: Avoid storing 'current' in another pointer Christophe Leroy

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