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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
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: [PATCH v3 30/41] powerpc/32: Only restore non volatile registers when required
Date: Fri, 12 Mar 2021 12:50:40 +0000 (UTC)	[thread overview]
Message-ID: <d1cb12d8023cc6afc1f07150565571373c04945c.1615552867.git.christophe.leroy@csgroup.eu> (raw)
In-Reply-To: <cover.1615552866.git.christophe.leroy@csgroup.eu>

Until now, non volatile registers were restored everytime they
were saved, ie using EXC_XFER_STD meant saving and restoring
them while EXC_XFER_LITE meant neither saving not restoring them.

Now that they are always saved, EXC_XFER_STD means to restore
them and EXC_XFER_LITE means to not restore them.

Most of the users of EXC_XFER_STD only need to retrieve the
non volatile registers. For them there is no need to restore
the non volatile registers as they have not been modified.

Only very few exceptions require non volatile registers restore.

Opencode the few places which require saving of non volatile
registers.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 arch/powerpc/kernel/entry_32.S       |  1 -
 arch/powerpc/kernel/head_40x.S       | 10 ++++++++--
 arch/powerpc/kernel/head_8xx.S       | 24 ++++++++++++++++++++----
 arch/powerpc/kernel/head_book3s_32.S | 17 ++++++++++++++---
 arch/powerpc/kernel/head_booke.h     | 10 ++++++++--
 arch/powerpc/kernel/head_fsl_booke.S | 16 ++++++++++++----
 6 files changed, 62 insertions(+), 16 deletions(-)

diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index 237b753720db..e6adb6882bde 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -358,7 +358,6 @@ _ASM_NOKPROBE_SYMBOL(fast_exception_return)
 
 	.globl	ret_from_except_full
 ret_from_except_full:
-	REST_NVGPRS(r1)
 	/* fall through */
 
 	.globl	ret_from_except
diff --git a/arch/powerpc/kernel/head_40x.S b/arch/powerpc/kernel/head_40x.S
index 7270caff665c..f3e5b462113f 100644
--- a/arch/powerpc/kernel/head_40x.S
+++ b/arch/powerpc/kernel/head_40x.S
@@ -228,12 +228,18 @@ _ASM_NOKPROBE_SYMBOL(\name\()_virt)
 /* 0x0600 - Alignment Exception */
 	START_EXCEPTION(0x0600, Alignment)
 	EXCEPTION_PROLOG 0x600 Alignment handle_dar_dsisr=1
-	EXC_XFER_STD(0x600, alignment_exception)
+	prepare_transfer_to_handler
+	bl	alignment_exception
+	REST_NVGPRS(r1)
+	b	interrupt_return
 
 /* 0x0700 - Program Exception */
 	START_EXCEPTION(0x0700, ProgramCheck)
 	EXCEPTION_PROLOG 0x700 ProgramCheck handle_dar_dsisr=1
-	EXC_XFER_STD(0x700, program_check_exception)
+	prepare_transfer_to_handler
+	bl	program_check_exception
+	REST_NVGPRS(r1)
+	b	interrupt_return
 
 	EXCEPTION(0x0800, Trap_08, unknown_exception, EXC_XFER_STD)
 	EXCEPTION(0x0900, Trap_09, unknown_exception, EXC_XFER_STD)
diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
index c48de97f42fc..86f844eb0e5a 100644
--- a/arch/powerpc/kernel/head_8xx.S
+++ b/arch/powerpc/kernel/head_8xx.S
@@ -131,10 +131,18 @@ instruction_counter:
 /* Alignment exception */
 	START_EXCEPTION(0x600, Alignment)
 	EXCEPTION_PROLOG 0x600 Alignment handle_dar_dsisr=1
-	EXC_XFER_STD(0x600, alignment_exception)
+	prepare_transfer_to_handler
+	bl	alignment_exception
+	REST_NVGPRS(r1)
+	b	interrupt_return
 
 /* Program check exception */
-	EXCEPTION(0x700, ProgramCheck, program_check_exception, EXC_XFER_STD)
+	START_EXCEPTION(0x700, ProgramCheck)
+	EXCEPTION_PROLOG 0x700 ProgramCheck
+	prepare_transfer_to_handler
+	bl	program_check_exception
+	REST_NVGPRS(r1)
+	b	interrupt_return
 
 /* Decrementer */
 	EXCEPTION(0x900, Decrementer, timer_interrupt, EXC_XFER_LITE)
@@ -149,7 +157,12 @@ instruction_counter:
 /* On the MPC8xx, this is a software emulation interrupt.  It occurs
  * for all unimplemented and illegal instructions.
  */
-	EXCEPTION(0x1000, SoftEmu, emulation_assist_interrupt, EXC_XFER_STD)
+	START_EXCEPTION(0x1000, SoftEmu)
+	EXCEPTION_PROLOG 0x1000 SoftEmu
+	prepare_transfer_to_handler
+	bl	emulation_assist_interrupt
+	REST_NVGPRS(r1)
+	b	interrupt_return
 
 /*
  * For the MPC8xx, this is a software tablewalk to load the instruction
@@ -348,7 +361,10 @@ DARFixed:/* Return from dcbx instruction bug workaround */
 	EXCEPTION_PROLOG_2 0x1c00 DataBreakpoint handle_dar_dsisr=1
 	mfspr	r4,SPRN_BAR
 	stw	r4,_DAR(r11)
-	EXC_XFER_STD(0x1c00, do_break)
+	prepare_transfer_to_handler
+	bl	do_break
+	REST_NVGPRS(r1)
+	b	interrupt_return
 
 #ifdef CONFIG_PERF_EVENTS
 	START_EXCEPTION(0x1d00, InstructionBreakpoint)
diff --git a/arch/powerpc/kernel/head_book3s_32.S b/arch/powerpc/kernel/head_book3s_32.S
index 2b4875ceaea4..425a4f20ceac 100644
--- a/arch/powerpc/kernel/head_book3s_32.S
+++ b/arch/powerpc/kernel/head_book3s_32.S
@@ -300,7 +300,10 @@ ALT_MMU_FTR_SECTION_END_IFSET(MMU_FTR_HPTE_TABLE)
 	andis.	r0, r5, DSISR_DABRMATCH@h
 	bne-	1f
 	EXC_XFER_LITE(0x300, do_page_fault)
-1:	EXC_XFER_STD(0x300, do_break)
+1:	prepare_transfer_to_handler
+	bl	do_break
+	REST_NVGPRS(r1)
+	b	interrupt_return
 
 
 /* Instruction access exception. */
@@ -336,10 +339,18 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_HPTE_TABLE)
 /* Alignment exception */
 	START_EXCEPTION(0x600, Alignment)
 	EXCEPTION_PROLOG 0x600 Alignment handle_dar_dsisr=1
-	EXC_XFER_STD(0x600, alignment_exception)
+	prepare_transfer_to_handler
+	bl	alignment_exception
+	REST_NVGPRS(r1)
+	b	interrupt_return
 
 /* Program check exception */
-	EXCEPTION(0x700, ProgramCheck, program_check_exception, EXC_XFER_STD)
+	START_EXCEPTION(0x700, ProgramCheck)
+	EXCEPTION_PROLOG 0x700 ProgramCheck
+	prepare_transfer_to_handler
+	bl	program_check_exception
+	REST_NVGPRS(r1)
+	b	interrupt_return
 
 /* Floating-point unavailable */
 	START_EXCEPTION(0x800, FPUnavailable)
diff --git a/arch/powerpc/kernel/head_booke.h b/arch/powerpc/kernel/head_booke.h
index 0f02b970e797..baf10556c587 100644
--- a/arch/powerpc/kernel/head_booke.h
+++ b/arch/powerpc/kernel/head_booke.h
@@ -483,14 +483,20 @@ ALT_FTR_SECTION_END_IFSET(CPU_FTR_EMB_HV)
 	NORMAL_EXCEPTION_PROLOG(0x600, ALIGNMENT);		      \
 	mfspr   r4,SPRN_DEAR;           /* Grab the DEAR and save it */	      \
 	stw     r4,_DEAR(r11);						      \
-	EXC_XFER_STD(0x0600, alignment_exception)
+	prepare_transfer_to_handler;					      \
+	bl	alignment_exception;					      \
+	REST_NVGPRS(r1);						      \
+	b	interrupt_return
 
 #define PROGRAM_EXCEPTION						      \
 	START_EXCEPTION(Program)					      \
 	NORMAL_EXCEPTION_PROLOG(0x700, PROGRAM);		      \
 	mfspr	r4,SPRN_ESR;		/* Grab the ESR and save it */	      \
 	stw	r4,_ESR(r11);						      \
-	EXC_XFER_STD(0x0700, program_check_exception)
+	prepare_transfer_to_handler;					      \
+	bl	program_check_exception;				      \
+	REST_NVGPRS(r1);						      \
+	b	interrupt_return
 
 #define DECREMENTER_EXCEPTION						      \
 	START_EXCEPTION(Decrementer)					      \
diff --git a/arch/powerpc/kernel/head_fsl_booke.S b/arch/powerpc/kernel/head_fsl_booke.S
index bf2730b4e43b..210871b2eb41 100644
--- a/arch/powerpc/kernel/head_fsl_booke.S
+++ b/arch/powerpc/kernel/head_fsl_booke.S
@@ -625,12 +625,20 @@ END_BTB_FLUSH_SECTION
 
 	/* SPE Floating Point Data */
 #ifdef CONFIG_SPE
-	EXCEPTION(0x2030, SPE_FP_DATA, SPEFloatingPointData,
-		  SPEFloatingPointException, EXC_XFER_STD)
+	START_EXCEPTION(SPEFloatingPointData)
+	NORMAL_EXCEPTION_PROLOG(0x2030, SPE_FP_DATA)
+	prepare_transfer_to_handler
+	bl	SPEFloatingPointException
+	REST_NVGPRS(r1)
+	b	interrupt_return
 
 	/* SPE Floating Point Round */
-	EXCEPTION(0x2050, SPE_FP_ROUND, SPEFloatingPointRound, \
-		  SPEFloatingPointRoundException, EXC_XFER_STD)
+	START_EXCEPTION(SPEFloatingPointRound)
+	NORMAL_EXCEPTION_PROLOG(0x2050, SPE_FP_ROUND)
+	prepare_transfer_to_handler
+	bl	SPEFloatingPointRoundException
+	REST_NVGPRS(r1)
+	b	interrupt_return
 #elif defined(CONFIG_SPE_POSSIBLE)
 	EXCEPTION(0x2040, SPE_FP_DATA, SPEFloatingPointData,
 		  unknown_exception, EXC_XFER_STD)
-- 
2.25.0


  parent reply	other threads:[~2021-03-12 12:51 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-12 12:50 [PATCH v3 00/41] powerpc/32: Switch to interrupt entry/exit in C Christophe Leroy
2021-03-12 12:50 ` [PATCH v3 01/41] powerpc/traps: Declare unrecoverable_exception() as __noreturn Christophe Leroy
2021-03-12 12:50 ` [PATCH v3 02/41] powerpc/40x: Don't use SPRN_SPRG_SCRATCH0/1 in TLB miss handlers Christophe Leroy
2021-03-12 12:50 ` [PATCH v3 03/41] powerpc/40x: Change CRITICAL_EXCEPTION_PROLOG macro to a gas macro Christophe Leroy
2021-03-12 12:50 ` [PATCH v3 04/41] powerpc/40x: Save SRR0/SRR1 and r10/r11 earlier in critical exception Christophe Leroy
2021-03-12 12:50 ` [PATCH v3 05/41] powerpc/40x: Reorder a few instructions in critical exception prolog Christophe Leroy
2021-03-12 12:50 ` [PATCH v3 06/41] powerpc/40x: Prepare for enabling MMU " Christophe Leroy
2021-03-12 12:50 ` [PATCH v3 07/41] powerpc/40x: Prepare normal exception handler for enabling MMU early Christophe Leroy
2021-03-12 12:50 ` [PATCH v3 08/41] powerpc/32: Reconcile interrupts in C Christophe Leroy
2021-03-12 12:50 ` [PATCH v3 09/41] powerpc/32: Entry cpu time accounting " Christophe Leroy
2021-03-12 12:50 ` [PATCH v3 10/41] powerpc/32: Handle bookE debugging in C in exception entry Christophe Leroy
2021-03-12 12:50 ` [PATCH v3 11/41] powerpc/32: Use fast instruction to set MSR RI in exception prolog on 8xx Christophe Leroy
2021-03-12 12:50 ` [PATCH v3 12/41] powerpc/32: Remove ksp_limit Christophe Leroy
2021-03-12 12:50 ` [PATCH v3 13/41] powerpc/32: Always enable data translation in exception prolog Christophe Leroy
2021-03-12 12:50 ` [PATCH v3 14/41] powerpc/32: Tag DAR in EXCEPTION_PROLOG_2 for the 8xx Christophe Leroy
2021-03-12 12:50 ` [PATCH v3 15/41] powerpc/32: Enable instruction translation at the same time as data translation Christophe Leroy
2021-03-12 12:50 ` [PATCH v3 16/41] powerpc/32: Statically initialise first emergency context Christophe Leroy
2021-03-12 12:50 ` [PATCH v3 17/41] powerpc/32: Add vmap_stack_overflow label inside the macro Christophe Leroy
2021-03-12 12:50 ` [PATCH v3 18/41] powerpc/32: Use START_EXCEPTION() as much as possible Christophe Leroy
2021-03-12 12:50 ` [PATCH v3 19/41] powerpc/32: Move exception prolog code into .text once MMU is back on Christophe Leroy
2021-03-12 12:50 ` [PATCH v3 20/41] powerpc/32: Provide a name to exception prolog continuation in virtual mode Christophe Leroy
2021-03-12 12:50 ` [PATCH v3 21/41] powerpc/32: Refactor booke critical registers saving Christophe Leroy
2021-03-12 12:50 ` [PATCH v3 22/41] powerpc/32: Perform normal function call in exception entry Christophe Leroy
2021-03-12 12:50 ` [PATCH v3 23/41] powerpc/32: Always save non volatile registers on " Christophe Leroy
2021-03-12 12:50 ` [PATCH v3 24/41] powerpc/32: Replace ASM exception exit by C exception exit from ppc64 Christophe Leroy
2021-03-12 12:50 ` [PATCH v3 25/41] powerpc/32: Don't save thread.regs on interrupt entry Christophe Leroy
2021-03-12 12:50 ` [PATCH v3 26/41] powerpc/32: Set regs parameter in r3 in transfer_to_handler Christophe Leroy
2021-03-12 12:50 ` [PATCH v3 27/41] powerpc/32: Call bad_page_fault() from do_page_fault() Christophe Leroy
2021-03-12 12:50 ` [PATCH v3 28/41] powerpc/32: Save trap number on stack in exception prolog Christophe Leroy
2021-03-12 12:50 ` [PATCH v3 29/41] powerpc/32: Add a prepare_transfer_to_handler macro for exception prologs Christophe Leroy
2021-03-12 12:50 ` Christophe Leroy [this message]
2021-03-12 12:50 ` [PATCH v3 31/41] powerpc/32: Dismantle EXC_XFER_STD/LITE/TEMPLATE Christophe Leroy
2021-07-31 10:12   ` Finn Thain
2021-07-31 15:39     ` Christophe Leroy
2021-08-01  1:21       ` Finn Thain
     [not found]         ` <34e52975-4ab9-4eb4-3501-02376e38a27c@yahoo.com>
2021-08-01 23:48           ` Finn Thain
2021-08-02 15:19         ` LEROY Christophe
2021-08-03  0:43           ` Finn Thain
     [not found]           ` <62d36dbb-4b39-f5bd-7962-4dcfbea729b3@linux-m68k.org>
     [not found]             ` <683c8156-97b0-5ba7-ce31-2e8613089836@yahoo.com>
2021-08-04  4:57               ` Finn Thain
2021-07-31 16:40     ` Christophe Leroy
2021-08-01  1:39       ` Finn Thain
2021-03-12 12:50 ` [PATCH v3 32/41] powerpc/32: Remove the xfer parameter in EXCEPTION() macro Christophe Leroy
2021-03-12 12:50 ` [PATCH v3 33/41] powerpc/32: Refactor saving of volatile registers in exception prologs Christophe Leroy
2021-03-12 12:50 ` [PATCH v3 34/41] powerpc/32: Save remaining registers in exception prolog Christophe Leroy
2021-03-12 12:50 ` [PATCH v3 35/41] powerpc/32: Return directly from power_save_ppc32_restore() Christophe Leroy
2021-03-12 12:50 ` [PATCH v3 36/41] powerpc/32: Only use prepare_transfer_to_handler function on book3s/32 and e500 Christophe Leroy
2021-03-12 12:50 ` [PATCH v3 37/41] powerpc/32s: Move KUEP locking/unlocking in C Christophe Leroy
2021-03-27 17:24   ` Christophe Leroy
2021-03-12 12:50 ` [PATCH v3 38/41] powerpc/64s: Make kuap_check_amr() and kuap_get_and_check_amr() generic Christophe Leroy
2021-03-12 12:50 ` [PATCH v3 39/41] powerpc/32s: Create C version of kuap save/restore/check helpers Christophe Leroy
2021-03-12 12:50 ` [PATCH v3 40/41] powerpc/8xx: " Christophe Leroy
2021-03-12 12:50 ` [PATCH v3 41/41] powerpc/32: Manage KUAP in C Christophe Leroy
2021-03-31  1:09 ` [PATCH v3 00/41] powerpc/32: Switch to interrupt entry/exit " Michael Ellerman

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