linux-kernel - [PATCH 4.4 018/266] powerpc/rfi-flush: Make it possible to call setup_rfi

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Date:   Wed, 15 May 2019 12:52:05 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Michael Ellerman <mpe@...erman.id.au>,
        Mauricio Faria de Oliveira <mauricfo@...ux.vnet.ibm.com>
Subject: [PATCH 4.4 018/266] powerpc/rfi-flush: Make it possible to call setup_rfi_flush() again

From: Michael Ellerman <mpe@...erman.id.au>

commit abf110f3e1cea40f5ea15e85f5d67c39c14568a7 upstream.

For PowerVM migration we want to be able to call setup_rfi_flush()
again after we've migrated the partition.

To support that we need to check that we're not trying to allocate the
fallback flush area after memblock has gone away (i.e., boot-time only).

Signed-off-by: Michael Ellerman <mpe@...erman.id.au>
Signed-off-by: Mauricio Faria de Oliveira <mauricfo@...ux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@...erman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 arch/powerpc/include/asm/setup.h |    2 +-
 arch/powerpc/kernel/setup_64.c   |    6 +++++-
 2 files changed, 6 insertions(+), 2 deletions(-)

--- a/arch/powerpc/include/asm/setup.h
+++ b/arch/powerpc/include/asm/setup.h
@@ -36,7 +36,7 @@ enum l1d_flush_type {
 	L1D_FLUSH_MTTRIG	= 0x8,
 };
 
-void __init setup_rfi_flush(enum l1d_flush_type, bool enable);
+void setup_rfi_flush(enum l1d_flush_type, bool enable);
 void do_rfi_flush_fixups(enum l1d_flush_type types);
 
 #endif /* !__ASSEMBLY__ */
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -887,6 +887,10 @@ static void init_fallback_flush(void)
 	u64 l1d_size, limit;
 	int cpu;
 
+	/* Only allocate the fallback flush area once (at boot time). */
+	if (l1d_flush_fallback_area)
+		return;
+
 	l1d_size = ppc64_caches.dsize;
 	limit = min(safe_stack_limit(), ppc64_rma_size);
 
@@ -904,7 +908,7 @@ static void init_fallback_flush(void)
 	}
 }
 
-void __init setup_rfi_flush(enum l1d_flush_type types, bool enable)
+void setup_rfi_flush(enum l1d_flush_type types, bool enable)
 {
 	if (types & L1D_FLUSH_FALLBACK) {
 		pr_info("rfi-flush: Using fallback displacement flush\n");