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Message-Id: <f7e9cb9e9240feec63cb330abf40b67d1aad852f.1604854583.git.christophe.leroy@csgroup.eu>
Date: Sun, 8 Nov 2020 16:57:37 +0000 (UTC)
From: Christophe Leroy <christophe.leroy@...roup.eu>
To: Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Paul Mackerras <paulus@...ba.org>,
Michael Ellerman <mpe@...erman.id.au>
Cc: linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH v2 3/3] powerpc: Remove RFI macro
RFI macro is just there to add an infinite loop past
rfi in order to avoid prefetch on 40x in half a dozen
of places in entry_32 and head_32.
Those places are already full of #ifdefs, so just add a
few more to explicitely show those loops and remove RFI.
Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
---
arch/powerpc/include/asm/ppc_asm.h | 5 -----
arch/powerpc/kernel/entry_32.S | 30 ++++++++++++++++++++++++------
arch/powerpc/kernel/head_32.h | 5 ++++-
3 files changed, 28 insertions(+), 12 deletions(-)
diff --git a/arch/powerpc/include/asm/ppc_asm.h b/arch/powerpc/include/asm/ppc_asm.h
index bedf3eb52ebc..101986d4a29d 100644
--- a/arch/powerpc/include/asm/ppc_asm.h
+++ b/arch/powerpc/include/asm/ppc_asm.h
@@ -498,11 +498,6 @@ END_FTR_SECTION_NESTED(CPU_FTR_CELL_TB_BUG, CPU_FTR_CELL_TB_BUG, 96)
#define MTMSRD(r) mtmsrd r
#define MTMSR_EERI(reg) mtmsrd reg,1
#else
-#ifndef CONFIG_40x
-#define RFI rfi
-#else
-#define RFI rfi; b . /* Prevent prefetch past rfi */
-#endif
#define MTMSRD(r) mtmsr r
#define MTMSR_EERI(reg) mtmsr reg
#endif
diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index e10e1167ffb1..c7c28e8acc10 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -234,7 +234,10 @@ transfer_to_handler_cont:
mtspr SPRN_SRR0,r11
mtspr SPRN_SRR1,r10
mtlr r9
- RFI /* jump to handler, enable MMU */
+ rfi /* jump to handler, enable MMU */
+#ifdef CONFIG_40x
+ b . /* Prevent prefetch past rfi */
+#endif
#if defined (CONFIG_PPC_BOOK3S_32) || defined(CONFIG_E500)
4: rlwinm r12,r12,0,~_TLF_NAPPING
@@ -263,7 +266,10 @@ _ASM_NOKPROBE_SYMBOL(transfer_to_handler_cont)
LOAD_REG_IMMEDIATE(r0, MSR_KERNEL)
mtspr SPRN_SRR0,r12
mtspr SPRN_SRR1,r0
- RFI
+ rfi
+#ifdef CONFIG_40x
+ b . /* Prevent prefetch past rfi */
+#endif
reenable_mmu:
/*
@@ -321,7 +327,10 @@ stack_ovf:
#endif
mtspr SPRN_SRR0,r9
mtspr SPRN_SRR1,r10
- RFI
+ rfi
+#ifdef CONFIG_40x
+ b . /* Prevent prefetch past rfi */
+#endif
_ASM_NOKPROBE_SYMBOL(stack_ovf)
#endif
@@ -470,7 +479,10 @@ syscall_exit_finish:
#endif
mtspr SPRN_SRR0,r7
mtspr SPRN_SRR1,r8
- RFI
+ rfi
+#ifdef CONFIG_40x
+ b . /* Prevent prefetch past rfi */
+#endif
_ASM_NOKPROBE_SYMBOL(syscall_exit_finish)
#ifdef CONFIG_44x
2: li r7,0
@@ -600,7 +612,10 @@ ret_from_kernel_syscall:
#endif
mtspr SPRN_SRR0, r9
mtspr SPRN_SRR1, r10
- RFI
+ rfi
+#ifdef CONFIG_40x
+ b . /* Prevent prefetch past rfi */
+#endif
_ASM_NOKPROBE_SYMBOL(ret_from_kernel_syscall)
/*
@@ -803,7 +818,10 @@ fast_exception_return:
REST_GPR(9, r11)
REST_GPR(12, r11)
lwz r11,GPR11(r11)
- RFI
+ rfi
+#ifdef CONFIG_40x
+ b . /* Prevent prefetch past rfi */
+#endif
_ASM_NOKPROBE_SYMBOL(fast_exception_return)
#if !(defined(CONFIG_4xx) || defined(CONFIG_BOOKE))
diff --git a/arch/powerpc/kernel/head_32.h b/arch/powerpc/kernel/head_32.h
index 7c767765071d..232000742c9a 100644
--- a/arch/powerpc/kernel/head_32.h
+++ b/arch/powerpc/kernel/head_32.h
@@ -222,7 +222,10 @@
#endif
mtspr SPRN_SRR1,r10
mtspr SPRN_SRR0,r11
- RFI /* jump to handler, enable MMU */
+ rfi /* jump to handler, enable MMU */
+#ifdef CONFIG_40x
+ b . /* Prevent prefetch past rfi */
+#endif
99: b ret_from_kernel_syscall
.endm
--
2.25.0
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