From: Christophe Leroy <christophe.leroy@c-s.fr>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-mm@kvack.org
Subject: [PATCH v4 15/16] powerpc/32s: avoid crossing page boundary while changing SRR0/1.
Date: Tue, 26 Nov 2019 12:36:19 +0000 (UTC) [thread overview]
Message-ID: <5bd5ce84265711f7611b028edbca7f0fe9565499.1574771541.git.christophe.leroy@c-s.fr> (raw)
In-Reply-To: <cover.1574771539.git.christophe.leroy@c-s.fr>
Trying VMAP_STACK with KVM, vmlinux was not starting.
This was due to SRR0 and SRR1 clobbered by an ISI due to
the rfi being in a different page than the mtsrr0/1:
c0003fe0 <mmu_off>:
c0003fe0: 38 83 00 54 addi r4,r3,84
c0003fe4: 7c 60 00 a6 mfmsr r3
c0003fe8: 70 60 00 30 andi. r0,r3,48
c0003fec: 4d 82 00 20 beqlr
c0003ff0: 7c 63 00 78 andc r3,r3,r0
c0003ff4: 7c 9a 03 a6 mtsrr0 r4
c0003ff8: 7c 7b 03 a6 mtsrr1 r3
c0003ffc: 7c 00 04 ac hwsync
c0004000: 4c 00 00 64 rfi
Align the 4 instruction block used to deactivate MMU to order 4,
so that the block never crosses a page boundary.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
arch/powerpc/kernel/head_32.S | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S
index 7ec780858299..90ef355e958b 100644
--- a/arch/powerpc/kernel/head_32.S
+++ b/arch/powerpc/kernel/head_32.S
@@ -917,6 +917,8 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_HPTE_TABLE)
ori r4,r4,2f@l
tophys(r4,r4)
li r3,MSR_KERNEL & ~(MSR_IR|MSR_DR)
+
+ .align 4
mtspr SPRN_SRR0,r4
mtspr SPRN_SRR1,r3
SYNC
@@ -1058,6 +1060,8 @@ _ENTRY(update_bats)
rlwinm r0, r6, 0, ~MSR_RI
rlwinm r0, r0, 0, ~MSR_EE
mtmsr r0
+
+ .align 4
mtspr SPRN_SRR0, r4
mtspr SPRN_SRR1, r3
SYNC
@@ -1097,6 +1101,8 @@ mmu_off:
andi. r0,r3,MSR_DR|MSR_IR /* MMU enabled? */
beqlr
andc r3,r3,r0
+
+ .align 4
mtspr SPRN_SRR0,r4
mtspr SPRN_SRR1,r3
sync
--
2.13.3
next prev parent reply other threads:[~2019-11-26 12:36 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-26 12:36 [PATCH v4 00/16] Enable CONFIG_VMAP_STACK on PPC32 Christophe Leroy
2019-11-26 12:36 ` [PATCH v4 01/16] powerpc/32: replace MTMSRD() by mtmsr Christophe Leroy
2019-11-26 12:36 ` [PATCH v4 02/16] powerpc/32: Add EXCEPTION_PROLOG_0 in head_32.h Christophe Leroy
2019-11-26 12:36 ` [PATCH v4 03/16] powerpc/32: save DEAR/DAR before calling handle_page_fault Christophe Leroy
2019-11-26 12:36 ` [PATCH v4 04/16] powerpc/32: move MSR_PR test into EXCEPTION_PROLOG_0 Christophe Leroy
2019-11-26 12:36 ` [PATCH v4 05/16] powerpc/32: add a macro to get and/or save DAR and DSISR on stack Christophe Leroy
2019-11-26 12:36 ` [PATCH v4 06/16] powerpc/32: prepare for CONFIG_VMAP_STACK Christophe Leroy
2019-11-26 12:36 ` [PATCH v4 07/16] powerpc: align stack to 2 * THREAD_SIZE with VMAP_STACK Christophe Leroy
2019-11-26 12:36 ` [PATCH v4 08/16] powerpc/32: Add early stack overflow detection with VMAP stack Christophe Leroy
2019-11-26 12:36 ` [PATCH v4 09/16] powerpc/8xx: Use alternative scratch registers in DTLB miss handler Christophe Leroy
2019-11-26 12:36 ` [PATCH v4 10/16] powerpc/8xx: drop exception entries for non-existing exceptions Christophe Leroy
2019-11-26 12:36 ` [PATCH v4 11/16] powerpc/8xx: move DataStoreTLBMiss perf handler Christophe Leroy
2019-11-26 12:36 ` [PATCH v4 12/16] powerpc/8xx: split breakpoint exception Christophe Leroy
2019-11-26 12:36 ` [PATCH v4 13/16] powerpc/8xx: Enable CONFIG_VMAP_STACK Christophe Leroy
2019-11-26 12:36 ` [PATCH v4 14/16] powerpc/32s: reorganise DSI handler Christophe Leroy
2019-11-26 12:36 ` Christophe Leroy [this message]
2019-11-26 12:36 ` [PATCH v4 16/16] powerpc/32s: Activate CONFIG_VMAP_STACK Christophe Leroy
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