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[192.237.175.120]) by mx.google.com with ESMTPS id d129si1390085ita.94.2019.05.14.05.13.07 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 14 May 2019 05:13:07 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of xen-devel-bounces@lists.xenproject.org designates 192.237.175.120 as permitted sender) client-ip=192.237.175.120; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of xen-devel-bounces@lists.xenproject.org designates 192.237.175.120 as permitted sender) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1hQWHa-0006GQ-NS; Tue, 14 May 2019 12:11:46 +0000 Received: from us1-rack-dfw2.inumbo.com ([104.130.134.6]) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1hQWHZ-0006FL-GP for xen-devel@lists.xenproject.org; Tue, 14 May 2019 12:11:45 +0000 X-Inumbo-ID: 7023b6cd-7641-11e9-8980-bc764e045a96 Received: from foss.arm.com (unknown [217.140.101.70]) by us1-rack-dfw2.inumbo.com (Halon) with ESMTP id 7023b6cd-7641-11e9-8980-bc764e045a96; Tue, 14 May 2019 12:11:43 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 996F5341; Tue, 14 May 2019 05:11:43 -0700 (PDT) Received: from e108454-lin.cambridge.arm.com (e108454-lin.cambridge.arm.com [10.1.196.50]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 5F89E3F71E; Tue, 14 May 2019 05:11:42 -0700 (PDT) From: Julien Grall To: xen-devel@lists.xenproject.org Date: Tue, 14 May 2019 13:11:27 +0100 Message-Id: <20190514121132.26732-4-julien.grall@arm.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20190514121132.26732-1-julien.grall@arm.com> References: <20190514121132.26732-1-julien.grall@arm.com> Subject: [Xen-devel] [PATCH MM-PART1 v3 3/8] xen/arm: Remove flush_xen_text_tlb_local() X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Oleksandr_Tyshchenko@epam.com, Julien Grall , Stefano Stabellini , Andrii Anisov MIME-Version: 1.0 Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" The function flush_xen_text_tlb_local() has been misused and will result to invalidate the instruction cache more than necessary. For instance, there is no need to invalidate the instruction cache if we are setting SCTLR_EL2.WXN. There is effectively only one caller (i.e free_init_memory() who would need to invalidate the instruction cache. So rather than keeping around the function flush_xen_text_tlb_local() replace it with call to flush_xen_tlb_local() and explicitely flush the cache when necessary. Signed-off-by: Julien Grall Reviewed-by: Andrii Anisov Reviewed-by: Stefano Stabellini --- Changes in v3: - Fix typoes Changes in v2: - Add Andrii's reviewed-by --- xen/arch/arm/mm.c | 17 ++++++++++++++--- xen/include/asm-arm/arm32/page.h | 23 +++++++++-------------- xen/include/asm-arm/arm64/page.h | 21 +++++---------------- 3 files changed, 28 insertions(+), 33 deletions(-) diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c index 93ad118183..dfbe39c70a 100644 --- a/xen/arch/arm/mm.c +++ b/xen/arch/arm/mm.c @@ -610,8 +610,12 @@ void __init remove_early_mappings(void) static void xen_pt_enforce_wnx(void) { WRITE_SYSREG32(READ_SYSREG32(SCTLR_EL2) | SCTLR_WXN, SCTLR_EL2); - /* Flush everything after setting WXN bit. */ - flush_xen_text_tlb_local(); + /* + * The TLBs may cache SCTLR_EL2.WXN. So ensure it is synchronized + * before flushing the TLBs. + */ + isb(); + flush_xen_data_tlb_local(); } extern void switch_ttbr(uint64_t ttbr); @@ -1123,7 +1127,7 @@ static void set_pte_flags_on_range(const char *p, unsigned long l, enum mg mg) } write_pte(xen_xenmap + i, pte); } - flush_xen_text_tlb_local(); + flush_xen_data_tlb_local(); } /* Release all __init and __initdata ranges to be reused */ @@ -1136,6 +1140,13 @@ void free_init_memory(void) uint32_t *p; set_pte_flags_on_range(__init_begin, len, mg_rw); + + /* + * From now on, init will not be used for execution anymore, + * so nuke the instruction cache to remove entries related to init. + */ + invalidate_icache_local(); + #ifdef CONFIG_ARM_32 /* udf instruction i.e (see A8.8.247 in ARM DDI 0406C.c) */ insn = 0xe7f000f0; diff --git a/xen/include/asm-arm/arm32/page.h b/xen/include/asm-arm/arm32/page.h index ea4b312c70..40a77daa9d 100644 --- a/xen/include/asm-arm/arm32/page.h +++ b/xen/include/asm-arm/arm32/page.h @@ -46,24 +46,19 @@ static inline void invalidate_icache(void) } /* - * Flush all hypervisor mappings from the TLB and branch predictor of - * the local processor. - * - * This is needed after changing Xen code mappings. - * - * The caller needs to issue the necessary DSB and D-cache flushes - * before calling flush_xen_text_tlb. + * Invalidate all instruction caches on the local processor to PoU. + * We also need to flush the branch predictor for ARMv7 as it may be + * architecturally visible to the software (see B2.2.4 in ARM DDI 0406C.b). */ -static inline void flush_xen_text_tlb_local(void) +static inline void invalidate_icache_local(void) { asm volatile ( - "isb;" /* Ensure synchronization with previous changes to text */ - CMD_CP32(TLBIALLH) /* Flush hypervisor TLB */ - CMD_CP32(ICIALLU) /* Flush I-cache */ - CMD_CP32(BPIALL) /* Flush branch predictor */ - "dsb;" /* Ensure completion of TLB+BP flush */ - "isb;" + CMD_CP32(ICIALLU) /* Flush I-cache. */ + CMD_CP32(BPIALL) /* Flush branch predictor. */ : : : "memory"); + + dsb(nsh); /* Ensure completion of the flush I-cache */ + isb(); /* Synchronize fetched instruction stream. */ } /* diff --git a/xen/include/asm-arm/arm64/page.h b/xen/include/asm-arm/arm64/page.h index 23d778154d..6c36d0210f 100644 --- a/xen/include/asm-arm/arm64/page.h +++ b/xen/include/asm-arm/arm64/page.h @@ -37,23 +37,12 @@ static inline void invalidate_icache(void) isb(); } -/* - * Flush all hypervisor mappings from the TLB of the local processor. - * - * This is needed after changing Xen code mappings. - * - * The caller needs to issue the necessary DSB and D-cache flushes - * before calling flush_xen_text_tlb. - */ -static inline void flush_xen_text_tlb_local(void) +/* Invalidate all instruction caches on the local processor to PoU */ +static inline void invalidate_icache_local(void) { - asm volatile ( - "isb;" /* Ensure synchronization with previous changes to text */ - "tlbi alle2;" /* Flush hypervisor TLB */ - "ic iallu;" /* Flush I-cache */ - "dsb sy;" /* Ensure completion of TLB flush */ - "isb;" - : : : "memory"); + asm volatile ("ic iallu"); + dsb(nsh); /* Ensure completion of the I-cache flush */ + isb(); } /*