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 18/23] powerpc/32: Remove verification of MSR_PR on syscall in the ASM entry
Date: Mon, 25 Jan 2021 14:48:31 +0000 (UTC) [thread overview]
Message-ID: <e309c0030f39fd3d8995beb12cb5d334306e87ac.1611585031.git.christophe.leroy@csgroup.eu> (raw)
In-Reply-To: <cover.1611585031.git.christophe.leroy@csgroup.eu>
system_call_exception() checks MSR_PR and BUGs if a syscall
is issued from kernel mode.
No need to handle it anymore from the ASM entry code.
null_syscall reduction 2 cycles (348 => 346 cycles)
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
arch/powerpc/kernel/entry_32.S | 30 ------------------------------
arch/powerpc/kernel/head_32.h | 3 ---
arch/powerpc/kernel/head_booke.h | 3 ---
3 files changed, 36 deletions(-)
diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index ce5fdb23ed7c..9922a04650f7 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -416,36 +416,6 @@ ret_from_kernel_thread:
li r3,0
b ret_from_syscall
- /*
- * System call was called from kernel. We get here with SRR1 in r9.
- * Mark the exception as recoverable once we have retrieved SRR0,
- * trap a warning and return ENOSYS with CR[SO] set.
- */
- .globl ret_from_kernel_syscall
-ret_from_kernel_syscall:
- mfspr r9, SPRN_SRR0
- mfspr r10, SPRN_SRR1
-#if !defined(CONFIG_4xx) && !defined(CONFIG_BOOKE)
- LOAD_REG_IMMEDIATE(r11, MSR_KERNEL & ~(MSR_IR|MSR_DR))
- mtmsr r11
-#endif
-
-0: trap
- EMIT_BUG_ENTRY 0b,__FILE__,__LINE__, BUGFLAG_WARNING
-
- li r3, ENOSYS
- crset so
-#if defined(CONFIG_PPC_8xx) && defined(CONFIG_PERF_EVENTS)
- mtspr SPRN_NRI, r0
-#endif
- mtspr SPRN_SRR0, r9
- mtspr SPRN_SRR1, r10
- rfi
-#ifdef CONFIG_40x
- b . /* Prevent prefetch past rfi */
-#endif
-_ASM_NOKPROBE_SYMBOL(ret_from_kernel_syscall)
-
/*
* Top-level page fault handling.
* This is in assembler because if do_page_fault tells us that
diff --git a/arch/powerpc/kernel/head_32.h b/arch/powerpc/kernel/head_32.h
index c2aa0d8f1f63..c0de4acbe3f8 100644
--- a/arch/powerpc/kernel/head_32.h
+++ b/arch/powerpc/kernel/head_32.h
@@ -118,8 +118,6 @@
.macro SYSCALL_ENTRY trapno
mfspr r9, SPRN_SRR1
mfspr r10, SPRN_SRR0
- andi. r11, r9, MSR_PR
- beq- 99f
LOAD_REG_IMMEDIATE(r11, MSR_KERNEL) /* can take exceptions */
lis r12, 1f@h
ori r12, r12, 1f@l
@@ -176,7 +174,6 @@
3:
#endif
b transfer_to_syscall /* jump to handler */
-99: b ret_from_kernel_syscall
.endm
.macro save_dar_dsisr_on_stack reg1, reg2, sp
diff --git a/arch/powerpc/kernel/head_booke.h b/arch/powerpc/kernel/head_booke.h
index faff094b650e..7af84e1e717b 100644
--- a/arch/powerpc/kernel/head_booke.h
+++ b/arch/powerpc/kernel/head_booke.h
@@ -106,10 +106,8 @@ ALT_FTR_SECTION_END_IFSET(CPU_FTR_EMB_HV)
#endif
mfspr r9, SPRN_SRR1
BOOKE_CLEAR_BTB(r11)
- andi. r11, r9, MSR_PR
lwz r11, TASK_STACK - THREAD(r10)
rlwinm r12,r12,0,4,2 /* Clear SO bit in CR */
- beq- 99f
ALLOC_STACK_FRAME(r11, THREAD_SIZE - INT_FRAME_SIZE)
stw r12, _CCR(r11) /* save various registers */
mflr r12
@@ -157,7 +155,6 @@ ALT_FTR_SECTION_END_IFSET(CPU_FTR_EMB_HV)
3:
b transfer_to_syscall /* jump to handler */
-99: b ret_from_kernel_syscall
.endm
/* To handle the additional exception priority levels on 40x and Book-E
--
2.25.0
next prev parent reply other threads:[~2021-01-25 15:18 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 ` [PATCH v4 03/23] powerpc/32: On syscall entry, enable instruction translation at the same time as data Christophe Leroy
2021-01-25 14:48 ` [PATCH v4 04/23] powerpc/32: Reorder instructions to avoid using CTR in syscall entry 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 ` Christophe Leroy [this message]
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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