From nobody Thu Oct 30 22:49:05 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) client-ip=192.237.175.120; envelope-from=xen-devel-bounces@lists.xenproject.org; helo=lists.xenproject.org; Authentication-Results: mx.zohomail.com; spf=pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org; dmarc=fail(p=none dis=none) header.from=arm.com Return-Path: Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) by mx.zohomail.com with SMTPS id 1753086744593470.9423525437654; Mon, 21 Jul 2025 01:32:24 -0700 (PDT) Received: from list by lists.xenproject.org with outflank-mailman.1051146.1419431 (Exim 4.92) (envelope-from ) id 1udlwQ-0005cG-Cz; Mon, 21 Jul 2025 08:32:10 +0000 Received: by outflank-mailman (output) from mailman id 1051146.1419431; Mon, 21 Jul 2025 08:32:10 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1udlwQ-0005c9-9e; Mon, 21 Jul 2025 08:32:10 +0000 Received: by outflank-mailman (input) for mailman id 1051146; Mon, 21 Jul 2025 08:32:09 +0000 Received: from se1-gles-sth1-in.inumbo.com ([159.253.27.254] helo=se1-gles-sth1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1udlwP-0005Wu-7M for xen-devel@lists.xenproject.org; Mon, 21 Jul 2025 08:32:09 +0000 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by se1-gles-sth1.inumbo.com (Halon) with ESMTP id 2f52f86f-660d-11f0-a31d-13f23c93f187; Mon, 21 Jul 2025 10:32:06 +0200 (CEST) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 160C41595; Mon, 21 Jul 2025 01:32:00 -0700 (PDT) Received: from PWQ0QT7DJ1.arm.com (unknown [10.57.71.32]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 93A2E3F66E; Mon, 21 Jul 2025 01:32:04 -0700 (PDT) X-Outflank-Mailman: Message body and most headers restored to incoming version X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 2f52f86f-660d-11f0-a31d-13f23c93f187 From: Hari Limaye To: xen-devel@lists.xenproject.org Cc: luca.fancellu@arm.com, Stefano Stabellini , Julien Grall , Bertrand Marquis , Michal Orzel , Volodymyr Babchuk Subject: [PATCH v4 1/6] arm/mpu: Find MPU region by range Date: Mon, 21 Jul 2025 09:31:42 +0100 Message-ID: <0ffb340dbfe50f0b3aa0a09c2b6e66cfb55047e3.1753084737.git.hari.limaye@arm.com> X-Mailer: git-send-email 2.42.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ZM-MESSAGEID: 1753086746536116600 Content-Type: text/plain; charset="utf-8" From: Luca Fancellu Implement a function to find the index of a MPU region in the xen_mpumap MPU region array. This function will be used in future commits to implement creating and destroying MPU regions. Signed-off-by: Luca Fancellu Signed-off-by: Hari Limaye Reviewed-by: Michal Orzel --- Changes from v1: - Update commit message - Remove internal _index variable - Simplify logic by disallowing NULL index parameter - Use normal printk - Reorder conditional checks - Update some comments Changes from v2: - Replace conditional with assert - Improve comments regarding base and limit - Space between ( and uint8_t. Changes from v3: - Add Michal's R-b --- xen/arch/arm/include/asm/mpu/mm.h | 29 ++++++++++++++++ xen/arch/arm/mpu/mm.c | 55 +++++++++++++++++++++++++++++++ 2 files changed, 84 insertions(+) diff --git a/xen/arch/arm/include/asm/mpu/mm.h b/xen/arch/arm/include/asm/m= pu/mm.h index a7f970b465..5a2b9b498b 100644 --- a/xen/arch/arm/include/asm/mpu/mm.h +++ b/xen/arch/arm/include/asm/mpu/mm.h @@ -10,6 +10,13 @@ #include #include =20 +#define MPUMAP_REGION_OVERLAP -1 +#define MPUMAP_REGION_NOTFOUND 0 +#define MPUMAP_REGION_FOUND 1 +#define MPUMAP_REGION_INCLUSIVE 2 + +#define INVALID_REGION_IDX 0xFFU + extern struct page_info *frame_table; =20 extern uint8_t max_mpu_regions; @@ -75,6 +82,28 @@ void write_protection_region(const pr_t *pr_write, uint8= _t sel); */ pr_t pr_of_addr(paddr_t base, paddr_t limit, unsigned int flags); =20 +/* + * Checks whether a given memory range is present in the provided table of + * MPU protection regions. + * + * @param table Array of pr_t protection regions. + * @param r_regions Number of elements in `table`. + * @param base Start of the memory region to be checked (inclusiv= e). + * @param limit End of the memory region to be checked (exclusive). + * @param index Set to the index of the region if an exact or incl= usive + * match is found, and INVALID_REGION otherwise. + * @return: Return code indicating the result of the search: + * MPUMAP_REGION_NOTFOUND: no part of the range is present in `ta= ble` + * MPUMAP_REGION_FOUND: found an exact match in `table` + * MPUMAP_REGION_INCLUSIVE: found an inclusive match in `table` + * MPUMAP_REGION_OVERLAP: found an overlap with a mapping in `tab= le` + * + * Note: make sure that the range [`base`, `limit`) refers to the memory r= egion + * inclusive of `base` and exclusive of `limit`. + */ +int mpumap_contains_region(pr_t *table, uint8_t nr_regions, paddr_t base, + paddr_t limit, uint8_t *index); + #endif /* __ARM_MPU_MM_H__ */ =20 /* diff --git a/xen/arch/arm/mpu/mm.c b/xen/arch/arm/mpu/mm.c index ccfb37a67b..407264a88c 100644 --- a/xen/arch/arm/mpu/mm.c +++ b/xen/arch/arm/mpu/mm.c @@ -110,6 +110,61 @@ pr_t pr_of_addr(paddr_t base, paddr_t limit, unsigned = int flags) return region; } =20 +int mpumap_contains_region(pr_t *table, uint8_t nr_regions, paddr_t base, + paddr_t limit, uint8_t *index) +{ + ASSERT(index); + *index =3D INVALID_REGION_IDX; + + /* + * The caller supplies a half-open interval [base, limit), i.e. limit = is the + * first byte *after* the region. Require limit strictly greater than = base, + * which is necessarily a non-empty region. + */ + ASSERT(base < limit); + + /* + * Internally we use inclusive bounds, so convert range to [base, limi= t-1]. + * The prior assertion guarantees the subtraction will not underflow. + */ + limit =3D limit - 1; + + for ( uint8_t i =3D 0; i < nr_regions; i++ ) + { + paddr_t iter_base =3D pr_get_base(&table[i]); + paddr_t iter_limit =3D pr_get_limit(&table[i]); + + /* Skip invalid (disabled) regions */ + if ( !region_is_valid(&table[i]) ) + continue; + + /* No match */ + if ( (iter_limit < base) || (iter_base > limit) ) + continue; + + /* Exact match */ + if ( (iter_base =3D=3D base) && (iter_limit =3D=3D limit) ) + { + *index =3D i; + return MPUMAP_REGION_FOUND; + } + + /* Inclusive match */ + if ( (base >=3D iter_base) && (limit <=3D iter_limit) ) + { + *index =3D i; + return MPUMAP_REGION_INCLUSIVE; + } + + /* Overlap */ + printk("Range %#"PRIpaddr" - %#"PRIpaddr" overlaps with the existi= ng region %#"PRIpaddr" - %#"PRIpaddr"\n", + base, limit + 1, iter_base, iter_limit + 1); + return MPUMAP_REGION_OVERLAP; + } + + return MPUMAP_REGION_NOTFOUND; +} + void __init setup_mm(void) { BUG_ON("unimplemented"); --=20 2.34.1 From nobody Thu Oct 30 22:49:05 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) client-ip=192.237.175.120; envelope-from=xen-devel-bounces@lists.xenproject.org; helo=lists.xenproject.org; Authentication-Results: mx.zohomail.com; spf=pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org; dmarc=fail(p=none dis=none) header.from=arm.com Return-Path: Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) by mx.zohomail.com with SMTPS id 1753086751408367.8743389894903; Mon, 21 Jul 2025 01:32:31 -0700 (PDT) Received: from list by lists.xenproject.org with outflank-mailman.1051148.1419441 (Exim 4.92) (envelope-from ) id 1udlwY-0005vQ-Je; Mon, 21 Jul 2025 08:32:18 +0000 Received: by outflank-mailman (output) from mailman id 1051148.1419441; Mon, 21 Jul 2025 08:32:18 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1udlwY-0005vJ-GR; Mon, 21 Jul 2025 08:32:18 +0000 Received: by outflank-mailman (input) for mailman id 1051148; Mon, 21 Jul 2025 08:32:17 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1udlwX-0005OI-Dn for xen-devel@lists.xenproject.org; Mon, 21 Jul 2025 08:32:17 +0000 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by se1-gles-flk1.inumbo.com (Halon) with ESMTP id 34dd4f4e-660d-11f0-b894-0df219b8e170; Mon, 21 Jul 2025 10:32:15 +0200 (CEST) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 47F131595; Mon, 21 Jul 2025 01:32:09 -0700 (PDT) Received: from PWQ0QT7DJ1.arm.com (unknown [10.57.71.32]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 99FC53F66E; Mon, 21 Jul 2025 01:32:13 -0700 (PDT) X-Outflank-Mailman: Message body and most headers restored to incoming version X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 34dd4f4e-660d-11f0-b894-0df219b8e170 From: Hari Limaye To: xen-devel@lists.xenproject.org Cc: luca.fancellu@arm.com, Stefano Stabellini , Julien Grall , Bertrand Marquis , Michal Orzel , Volodymyr Babchuk , Ayan Kumar Halder Subject: [PATCH v4 2/6] xen/arm: Introduce flags_has_rwx helper Date: Mon, 21 Jul 2025 09:31:43 +0100 Message-ID: X-Mailer: git-send-email 2.42.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ZM-MESSAGEID: 1753086752648116600 Content-Type: text/plain; charset="utf-8" From: Luca Fancellu Introduce flags_has_rwx() function that will check if a mapping is both writable and executable when modifying or updating the mapping. This check was already present in pt.c but since it will be used also for MPU systems, it's wrapped into a function now. Signed-off-by: Luca Fancellu Signed-off-by: Hari Limaye Reviewed-by: Ayan Kumar Halder Reviewed-by: Michal Orzel --- Changes from v1: - Add Ayan and Michal's R-b - Fix typos --- xen/arch/arm/include/asm/mm.h | 2 ++ xen/arch/arm/mm.c | 15 +++++++++++++++ xen/arch/arm/mmu/pt.c | 9 +-------- 3 files changed, 18 insertions(+), 8 deletions(-) diff --git a/xen/arch/arm/include/asm/mm.h b/xen/arch/arm/include/asm/mm.h index 011bc1fd30..fb79aeb088 100644 --- a/xen/arch/arm/include/asm/mm.h +++ b/xen/arch/arm/include/asm/mm.h @@ -192,6 +192,8 @@ extern unsigned long frametable_base_pdx; =20 /* Boot-time pagetable setup */ extern void setup_pagetables(void); +/* Check that the mapping flag has no W and X together */ +bool flags_has_rwx(unsigned int flags); /* Map FDT in boot pagetable */ extern void *early_fdt_map(paddr_t fdt_paddr); /* Remove early mappings */ diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c index 0613c19169..77e21f5f29 100644 --- a/xen/arch/arm/mm.c +++ b/xen/arch/arm/mm.c @@ -24,6 +24,21 @@ =20 unsigned long frametable_base_pdx __read_mostly; =20 +bool flags_has_rwx(unsigned int flags) +{ + /* + * The hardware was configured to forbid mapping both writable and + * executable. + * When modifying/creating mapping (i.e _PAGE_PRESENT is set), + * prevent any update if this happen. + */ + if ( (flags & _PAGE_PRESENT) && !PAGE_RO_MASK(flags) && + !PAGE_XN_MASK(flags) ) + return true; + else + return false; +} + void flush_page_to_ram(unsigned long mfn, bool sync_icache) { void *v =3D map_domain_page(_mfn(mfn)); diff --git a/xen/arch/arm/mmu/pt.c b/xen/arch/arm/mmu/pt.c index 4726e713ef..621b47dbf5 100644 --- a/xen/arch/arm/mmu/pt.c +++ b/xen/arch/arm/mmu/pt.c @@ -610,14 +610,7 @@ static int xen_pt_update(unsigned long virt, */ const mfn_t root =3D maddr_to_mfn(READ_SYSREG64(TTBR0_EL2)); =20 - /* - * The hardware was configured to forbid mapping both writeable and - * executable. - * When modifying/creating mapping (i.e _PAGE_PRESENT is set), - * prevent any update if this happen. - */ - if ( (flags & _PAGE_PRESENT) && !PAGE_RO_MASK(flags) && - !PAGE_XN_MASK(flags) ) + if ( flags_has_rwx(flags) ) { mm_printk("Mappings should not be both Writeable and Executable.\n= "); return -EINVAL; --=20 2.34.1 From nobody Thu Oct 30 22:49:05 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) client-ip=192.237.175.120; envelope-from=xen-devel-bounces@lists.xenproject.org; helo=lists.xenproject.org; Authentication-Results: mx.zohomail.com; spf=pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org; dmarc=fail(p=none dis=none) header.from=arm.com Return-Path: Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) by mx.zohomail.com with SMTPS id 1753086760560807.7447220019915; Mon, 21 Jul 2025 01:32:40 -0700 (PDT) Received: from list by lists.xenproject.org with outflank-mailman.1051151.1419451 (Exim 4.92) (envelope-from ) id 1udlwh-0006SF-Rm; Mon, 21 Jul 2025 08:32:27 +0000 Received: by outflank-mailman (output) from mailman id 1051151.1419451; Mon, 21 Jul 2025 08:32:27 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1udlwh-0006S5-OI; Mon, 21 Jul 2025 08:32:27 +0000 Received: by outflank-mailman (input) for mailman id 1051151; Mon, 21 Jul 2025 08:32:27 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1udlwh-0005OI-1w for xen-devel@lists.xenproject.org; Mon, 21 Jul 2025 08:32:27 +0000 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by se1-gles-flk1.inumbo.com (Halon) with ESMTP id 3a7f46fb-660d-11f0-b894-0df219b8e170; Mon, 21 Jul 2025 10:32:25 +0200 (CEST) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id B4EE4153B; Mon, 21 Jul 2025 01:32:18 -0700 (PDT) Received: from PWQ0QT7DJ1.arm.com (unknown [10.57.71.32]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id C6F333F66E; Mon, 21 Jul 2025 01:32:22 -0700 (PDT) X-Outflank-Mailman: Message body and most headers restored to incoming version X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 3a7f46fb-660d-11f0-b894-0df219b8e170 From: Hari Limaye To: xen-devel@lists.xenproject.org Cc: luca.fancellu@arm.com, Penny Zheng , Stefano Stabellini , Julien Grall , Bertrand Marquis , Michal Orzel , Volodymyr Babchuk , Penny Zheng , Wei Chen Subject: [PATCH v4 3/6] arm/mpu: Populate a new region in Xen MPU mapping table Date: Mon, 21 Jul 2025 09:31:44 +0100 Message-ID: <740a990a7579a53f69bb2b27b55a74093fd52d7e.1753084737.git.hari.limaye@arm.com> X-Mailer: git-send-email 2.42.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ZM-MESSAGEID: 1753086762635116600 Content-Type: text/plain; charset="utf-8" From: Penny Zheng Introduce map_pages_to_xen() that is implemented using a new helper, xen_mpumap_update(), which is responsible for updating Xen MPU memory mapping table(xen_mpumap), including creating a new entry, updating or destroying an existing one, it is equivalent to xen_pt_update in MMU. This commit only implements populating a new entry in Xen MPU memory mapping table(xen_mpumap). Signed-off-by: Penny Zheng Signed-off-by: Wei Chen Signed-off-by: Luca Fancellu Signed-off-by: Hari Limaye Reviewed-by: Michal Orzel --- Changes from v1: - Simplify if condition - Use normal printk - Use %# over 0x% - Add same asserts as in Patch 4 Changes from v2: - Improve clarity in xen_mpumap_alloc_entry comment - Simplify if condition - Remove redundant ASSERT statements - Add check for `base >=3D limit` - Pass virt directly in map_pages_to_xen - Move call to `context_sync_mpu` inside locked section of `xen_mpumap_upda= te` - Move _PAGE_PRESENT check before calling `mpumap_contains_region` Changes from v3: - Add Michal's R-b --- xen/arch/arm/include/asm/mpu/mm.h | 12 ++++ xen/arch/arm/mpu/mm.c | 103 ++++++++++++++++++++++++++++++ 2 files changed, 115 insertions(+) diff --git a/xen/arch/arm/include/asm/mpu/mm.h b/xen/arch/arm/include/asm/m= pu/mm.h index 5a2b9b498b..c32fac8905 100644 --- a/xen/arch/arm/include/asm/mpu/mm.h +++ b/xen/arch/arm/include/asm/mpu/mm.h @@ -64,6 +64,7 @@ static inline void context_sync_mpu(void) * The following API requires context_sync_mpu() after being used to modif= y MPU * regions: * - write_protection_region + * - xen_mpumap_update */ =20 /* Reads the MPU region (into @pr_read) with index @sel from the HW */ @@ -72,6 +73,17 @@ void read_protection_region(pr_t *pr_read, uint8_t sel); /* Writes the MPU region (from @pr_write) with index @sel to the HW */ void write_protection_region(const pr_t *pr_write, uint8_t sel); =20 +/* + * Maps an address range into the MPU data structure and updates the HW. + * Equivalent to xen_pt_update in an MMU system. + * + * @param base Base address of the range to map (inclusive). + * @param limit Limit address of the range to map (exclusive). + * @param flags Flags for the memory range to map. + * @return 0 on success, negative on error. + */ +int xen_mpumap_update(paddr_t base, paddr_t limit, unsigned int flags); + /* * Creates a pr_t structure describing a protection region. * diff --git a/xen/arch/arm/mpu/mm.c b/xen/arch/arm/mpu/mm.c index 407264a88c..d5426525af 100644 --- a/xen/arch/arm/mpu/mm.c +++ b/xen/arch/arm/mpu/mm.c @@ -6,6 +6,7 @@ #include #include #include +#include #include #include #include @@ -29,6 +30,8 @@ DECLARE_BITMAP(xen_mpumap_mask, MAX_MPU_REGION_NR) \ /* EL2 Xen MPU memory region mapping table. */ pr_t __cacheline_aligned __section(".data") xen_mpumap[MAX_MPU_REGION_NR]; =20 +static DEFINE_SPINLOCK(xen_mpumap_lock); + static void __init __maybe_unused build_assertions(void) { /* @@ -165,6 +168,106 @@ int mpumap_contains_region(pr_t *table, uint8_t nr_re= gions, paddr_t base, return MPUMAP_REGION_NOTFOUND; } =20 +/* + * Allocate an entry for a new EL2 MPU region in the bitmap xen_mpumap_mas= k. + * @param idx Set to the index of the allocated EL2 MPU region on succes= s. + * @return 0 on success, otherwise -ENOENT on failure. + */ +static int xen_mpumap_alloc_entry(uint8_t *idx) +{ + ASSERT(spin_is_locked(&xen_mpumap_lock)); + + *idx =3D find_first_zero_bit(xen_mpumap_mask, max_mpu_regions); + if ( *idx =3D=3D max_mpu_regions ) + { + printk(XENLOG_ERR "mpu: EL2 MPU memory region mapping pool exhaust= ed\n"); + return -ENOENT; + } + + set_bit(*idx, xen_mpumap_mask); + + return 0; +} + +/* + * Update the entry in the MPU memory region mapping table (xen_mpumap) fo= r the + * given memory range and flags, creating one if none exists. + * + * @param base Base address (inclusive). + * @param limit Limit address (exclusive). + * @param flags Region attributes (a combination of PAGE_HYPERVISOR_XXX) + * @return 0 on success, otherwise negative on error. + */ +static int xen_mpumap_update_entry(paddr_t base, paddr_t limit, + unsigned int flags) +{ + uint8_t idx; + int rc; + + ASSERT(spin_is_locked(&xen_mpumap_lock)); + + /* Currently only region creation is supported. */ + if ( !(flags & _PAGE_PRESENT) ) + return -EINVAL; + + rc =3D mpumap_contains_region(xen_mpumap, max_mpu_regions, base, limit= , &idx); + if ( rc !=3D MPUMAP_REGION_NOTFOUND ) + return -EINVAL; + + /* We are inserting a mapping =3D> Create new region. */ + rc =3D xen_mpumap_alloc_entry(&idx); + if ( rc ) + return -ENOENT; + + xen_mpumap[idx] =3D pr_of_addr(base, limit, flags); + + write_protection_region(&xen_mpumap[idx], idx); + + return 0; +} + +int xen_mpumap_update(paddr_t base, paddr_t limit, unsigned int flags) +{ + int rc; + + if ( flags_has_rwx(flags) ) + { + printk("Mappings should not be both Writeable and Executable\n"); + return -EINVAL; + } + + if ( base >=3D limit ) + { + printk("Base address %#"PRIpaddr" must be smaller than limit addre= ss %#"PRIpaddr"\n", + base, limit); + return -EINVAL; + } + + if ( !IS_ALIGNED(base, PAGE_SIZE) || !IS_ALIGNED(limit, PAGE_SIZE) ) + { + printk("base address %#"PRIpaddr", or limit address %#"PRIpaddr" i= s not page aligned\n", + base, limit); + return -EINVAL; + } + + spin_lock(&xen_mpumap_lock); + + rc =3D xen_mpumap_update_entry(base, limit, flags); + if ( !rc ) + context_sync_mpu(); + + spin_unlock(&xen_mpumap_lock); + + return rc; +} + +int map_pages_to_xen(unsigned long virt, mfn_t mfn, unsigned long nr_mfns, + unsigned int flags) +{ + /* MPU systems have no translation, ma =3D=3D va, so pass virt directl= y */ + return xen_mpumap_update(virt, mfn_to_maddr(mfn_add(mfn, nr_mfns)), fl= ags); +} + void __init setup_mm(void) { BUG_ON("unimplemented"); --=20 2.34.1 From nobody Thu Oct 30 22:49:05 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) client-ip=192.237.175.120; envelope-from=xen-devel-bounces@lists.xenproject.org; helo=lists.xenproject.org; Authentication-Results: mx.zohomail.com; spf=pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org; 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Mon, 21 Jul 2025 10:32:31 +0200 (CEST) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 3D8A3153B; Mon, 21 Jul 2025 01:32:25 -0700 (PDT) Received: from PWQ0QT7DJ1.arm.com (unknown [10.57.71.32]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 4CCB73F66E; Mon, 21 Jul 2025 01:32:29 -0700 (PDT) X-Outflank-Mailman: Message body and most headers restored to incoming version X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 3e6a93c3-660d-11f0-b894-0df219b8e170 From: Hari Limaye To: xen-devel@lists.xenproject.org Cc: luca.fancellu@arm.com, Penny Zheng , Stefano Stabellini , Julien Grall , Bertrand Marquis , Michal Orzel , Volodymyr Babchuk , Penny Zheng , Wei Chen Subject: [PATCH v4 4/6] arm/mpu: Destroy an existing entry in Xen MPU memory mapping table Date: Mon, 21 Jul 2025 09:31:45 +0100 Message-ID: <7050dc0abf9efb69958a8b4fcc1c325d2e937fea.1753084737.git.hari.limaye@arm.com> X-Mailer: git-send-email 2.42.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ZM-MESSAGEID: 1753086766705116600 Content-Type: text/plain; charset="utf-8" From: Penny Zheng This commit expands xen_mpumap_update/xen_mpumap_update_entry to include destroying an existing entry. We define a new helper "disable_mpu_region_from_index" to disable the MPU region based on index. If region is within [0, 31], we could quickly disable the MPU region through PRENR_EL2 which provides direct access to the PRLAR_EL2.EN bits of EL2 MPU regions. Rignt now, we only support destroying a *WHOLE* MPU memory region, part-region removing is not supported, as in worst case, it will leave two fragments behind. Signed-off-by: Penny Zheng Signed-off-by: Wei Chen Signed-off-by: Luca Fancellu Signed-off-by: Hari Limaye Reviewed-by: Michal Orzel --- Changes from v1: - Move check for part-region removal outside if condition - Use normal printk Changes from v2: - Fix assert from `ASSERT(s <=3D e)` -> `ASSERT(s < e)` - Remove call to context_sync_mpu - Use register_t - Improve sanity checking to catch modification & removing non-existent entries - Update check for MPUMAP_REGION_INCLUSIVE to be generic Changes from v3: - Move early return for modifying case above MPUMAP_REGION_INCLUSIVE check - Add bool variable to store `flags & _PAGE_PRESENT` - Remove calls to `virt_to_maddr` --- xen/arch/arm/include/asm/mpu.h | 2 + xen/arch/arm/include/asm/mpu/cpregs.h | 4 ++ xen/arch/arm/mpu/mm.c | 95 ++++++++++++++++++++++++--- 3 files changed, 92 insertions(+), 9 deletions(-) diff --git a/xen/arch/arm/include/asm/mpu.h b/xen/arch/arm/include/asm/mpu.h index 63560c613b..5053edaf63 100644 --- a/xen/arch/arm/include/asm/mpu.h +++ b/xen/arch/arm/include/asm/mpu.h @@ -23,6 +23,8 @@ #define NUM_MPU_REGIONS_MASK (NUM_MPU_REGIONS - 1) #define MAX_MPU_REGION_NR NUM_MPU_REGIONS_MASK =20 +#define PRENR_MASK GENMASK(31, 0) + #ifndef __ASSEMBLY__ =20 /* diff --git a/xen/arch/arm/include/asm/mpu/cpregs.h b/xen/arch/arm/include/a= sm/mpu/cpregs.h index bb15e02df6..9f3b32acd7 100644 --- a/xen/arch/arm/include/asm/mpu/cpregs.h +++ b/xen/arch/arm/include/asm/mpu/cpregs.h @@ -6,6 +6,9 @@ /* CP15 CR0: MPU Type Register */ #define HMPUIR p15,4,c0,c0,4 =20 +/* CP15 CR6: Protection Region Enable Register */ +#define HPRENR p15,4,c6,c1,1 + /* CP15 CR6: MPU Protection Region Base/Limit/Select Address Register */ #define HPRSELR p15,4,c6,c2,1 #define HPRBAR p15,4,c6,c3,0 @@ -82,6 +85,7 @@ /* Alphabetically... */ #define MPUIR_EL2 HMPUIR #define PRBAR_EL2 HPRBAR +#define PRENR_EL2 HPRENR #define PRLAR_EL2 HPRLAR #define PRSELR_EL2 HPRSELR #endif /* CONFIG_ARM_32 */ diff --git a/xen/arch/arm/mpu/mm.c b/xen/arch/arm/mpu/mm.c index d5426525af..2154b3720d 100644 --- a/xen/arch/arm/mpu/mm.c +++ b/xen/arch/arm/mpu/mm.c @@ -189,6 +189,42 @@ static int xen_mpumap_alloc_entry(uint8_t *idx) return 0; } =20 +/* + * Disable and remove an MPU region from the data structure and MPU regist= ers. + * + * @param index Index of the MPU region to be disabled. + */ +static void disable_mpu_region_from_index(uint8_t index) +{ + ASSERT(spin_is_locked(&xen_mpumap_lock)); + ASSERT(index !=3D INVALID_REGION_IDX); + + if ( !region_is_valid(&xen_mpumap[index]) ) + { + printk(XENLOG_WARNING + "mpu: MPU memory region[%u] is already disabled\n", index); + return; + } + + /* Zeroing the region will also zero the region enable */ + memset(&xen_mpumap[index], 0, sizeof(pr_t)); + clear_bit(index, xen_mpumap_mask); + + /* + * Both Armv8-R AArch64 and AArch32 have direct access to the enable b= it for + * MPU regions numbered from 0 to 31. + */ + if ( (index & PRENR_MASK) !=3D 0 ) + { + /* Clear respective bit */ + register_t val =3D READ_SYSREG(PRENR_EL2) & (~(1UL << index)); + + WRITE_SYSREG(val, PRENR_EL2); + } + else + write_protection_region(&xen_mpumap[index], index); +} + /* * Update the entry in the MPU memory region mapping table (xen_mpumap) fo= r the * given memory range and flags, creating one if none exists. @@ -201,27 +237,59 @@ static int xen_mpumap_alloc_entry(uint8_t *idx) static int xen_mpumap_update_entry(paddr_t base, paddr_t limit, unsigned int flags) { + bool flags_has_page_present; uint8_t idx; int rc; =20 ASSERT(spin_is_locked(&xen_mpumap_lock)); =20 - /* Currently only region creation is supported. */ - if ( !(flags & _PAGE_PRESENT) ) + rc =3D mpumap_contains_region(xen_mpumap, max_mpu_regions, base, limit= , &idx); + if ( rc < 0 ) return -EINVAL; =20 - rc =3D mpumap_contains_region(xen_mpumap, max_mpu_regions, base, limit= , &idx); - if ( rc !=3D MPUMAP_REGION_NOTFOUND ) + flags_has_page_present =3D flags & _PAGE_PRESENT; + + /* Currently we don't support modifying an existing entry. */ + if ( flags_has_page_present && (rc >=3D MPUMAP_REGION_FOUND) ) + { + printk("mpu: modifying an existing entry is not supported\n"); return -EINVAL; + } + + /* + * Currently, we only support removing/modifying a *WHOLE* MPU memory + * region. Part-region removal/modification is not supported as in the= worst + * case it will leave two/three fragments behind. + */ + if ( rc =3D=3D MPUMAP_REGION_INCLUSIVE ) + { + printk("mpu: part-region removal/modification is not supported\n"); + return -EINVAL; + } =20 /* We are inserting a mapping =3D> Create new region. */ - rc =3D xen_mpumap_alloc_entry(&idx); - if ( rc ) - return -ENOENT; + if ( flags_has_page_present && (MPUMAP_REGION_NOTFOUND =3D=3D rc) ) + { + rc =3D xen_mpumap_alloc_entry(&idx); + if ( rc ) + return -ENOENT; + + xen_mpumap[idx] =3D pr_of_addr(base, limit, flags); =20 - xen_mpumap[idx] =3D pr_of_addr(base, limit, flags); + write_protection_region(&xen_mpumap[idx], idx); + } + + /* Removing a mapping */ + if ( !flags_has_page_present ) + { + if ( rc =3D=3D MPUMAP_REGION_NOTFOUND ) + { + printk("mpu: cannot remove an entry that does not exist\n"); + return -EINVAL; + } =20 - write_protection_region(&xen_mpumap[idx], idx); + disable_mpu_region_from_index(idx); + } =20 return 0; } @@ -261,6 +329,15 @@ int xen_mpumap_update(paddr_t base, paddr_t limit, uns= igned int flags) return rc; } =20 +int destroy_xen_mappings(unsigned long s, unsigned long e) +{ + ASSERT(IS_ALIGNED(s, PAGE_SIZE)); + ASSERT(IS_ALIGNED(e, PAGE_SIZE)); + ASSERT(s < e); + + return xen_mpumap_update(s, e, 0); +} + int map_pages_to_xen(unsigned long virt, mfn_t mfn, unsigned long nr_mfns, unsigned int flags) { --=20 2.34.1 From nobody Thu Oct 30 22:49:05 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) client-ip=192.237.175.120; envelope-from=xen-devel-bounces@lists.xenproject.org; helo=lists.xenproject.org; Authentication-Results: mx.zohomail.com; spf=pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org; dmarc=fail(p=none dis=none) header.from=arm.com Return-Path: Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) by mx.zohomail.com with SMTPS id 1753086770496837.02236606163; Mon, 21 Jul 2025 01:32:50 -0700 (PDT) Received: from list by lists.xenproject.org with outflank-mailman.1051163.1419471 (Exim 4.92) (envelope-from ) id 1udlwt-0007LO-Ck; Mon, 21 Jul 2025 08:32:39 +0000 Received: by outflank-mailman (output) from mailman id 1051163.1419471; Mon, 21 Jul 2025 08:32:39 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1udlwt-0007LC-9H; Mon, 21 Jul 2025 08:32:39 +0000 Received: by outflank-mailman (input) for mailman id 1051163; Mon, 21 Jul 2025 08:32:37 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1udlwr-0005OI-KD for xen-devel@lists.xenproject.org; Mon, 21 Jul 2025 08:32:37 +0000 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by se1-gles-flk1.inumbo.com (Halon) with ESMTP id 40d39d8e-660d-11f0-b894-0df219b8e170; Mon, 21 Jul 2025 10:32:35 +0200 (CEST) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 439FD153B; Mon, 21 Jul 2025 01:32:29 -0700 (PDT) Received: from PWQ0QT7DJ1.arm.com (unknown [10.57.71.32]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 9F8713F66E; Mon, 21 Jul 2025 01:32:33 -0700 (PDT) X-Outflank-Mailman: Message body and most headers restored to incoming version X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 40d39d8e-660d-11f0-b894-0df219b8e170 From: Hari Limaye To: xen-devel@lists.xenproject.org Cc: luca.fancellu@arm.com, Stefano Stabellini , Julien Grall , Bertrand Marquis , Michal Orzel , Volodymyr Babchuk , Ayan Kumar Halder Subject: [PATCH v4 5/6] arm/mpu: Implement early_fdt_map support in MPU systems Date: Mon, 21 Jul 2025 09:31:46 +0100 Message-ID: <3326c844f49a94228c1d79fc1afec614691d4a2a.1753084737.git.hari.limaye@arm.com> X-Mailer: git-send-email 2.42.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ZM-MESSAGEID: 1753086772661116600 Content-Type: text/plain; charset="utf-8" From: Luca Fancellu Implement the function early_fdt_map(), which is responsible for mapping the Device Tree Blob in the early stages of the boot process, for MPU systems. We make use of the map_pages_to_xen() and destroy_xen_mappings() APIs. In particular the latter function is necessary in the case that the initial mapping of the fdt_header is insufficient to cover the entire DTB, as we must destroy and then remap the region due to the APIs no providing support for extending the size of an existing region. Signed-off-by: Luca Fancellu Signed-off-by: Hari Limaye Reviewed-by: Ayan Kumar Halder Reviewed-by: Michal Orzel --- Changes from v1: - Add Ayan's R-b Changes from v2: - Rename mapped_fdt_paddr -> mapped_fdt_base - Remove full stops - Add sanity check for MAX_FDT_SIZE - Improve comment regarding early return when DTB already mapped Changes from v3: - Use ASSERT instead of conditional check that `mapped_fdt_base =3D=3D INVALID_PADDR` --- xen/arch/arm/mpu/setup.c | 73 ++++++++++++++++++++++++++++++++++++++-- 1 file changed, 71 insertions(+), 2 deletions(-) diff --git a/xen/arch/arm/mpu/setup.c b/xen/arch/arm/mpu/setup.c index b4da77003f..2ef703757f 100644 --- a/xen/arch/arm/mpu/setup.c +++ b/xen/arch/arm/mpu/setup.c @@ -1,17 +1,86 @@ /* SPDX-License-Identifier: GPL-2.0-only */ =20 +#include #include #include +#include #include +#include #include +#include #include =20 +static paddr_t __initdata mapped_fdt_base =3D INVALID_PADDR; +static paddr_t __initdata mapped_fdt_limit =3D INVALID_PADDR; + void __init setup_pagetables(void) {} =20 void * __init early_fdt_map(paddr_t fdt_paddr) { - BUG_ON("unimplemented"); - return NULL; + /* Map at least a page containing the DTB address, exclusive range */ + paddr_t base =3D round_pgdown(fdt_paddr); + paddr_t limit =3D round_pgup(fdt_paddr + sizeof(struct fdt_header)); + unsigned int flags =3D PAGE_HYPERVISOR_RO; + void *fdt_virt =3D (void *)fdt_paddr; /* virt =3D=3D paddr for MPU */ + int rc; + uint32_t size; + unsigned long nr_mfns; + + /* + * Check whether the physical FDT address is set and meets the minimum + * alignment requirement. Since we are relying on MIN_FDT_ALIGN to be = at + * least 8 bytes so that we always access the magic and size fields + * of the FDT header after mapping the first chunk, double check if + * that is indeed the case. + */ + BUILD_BUG_ON(MIN_FDT_ALIGN < 8); + if ( !fdt_paddr || fdt_paddr % MIN_FDT_ALIGN ) + return NULL; + + /* + * DTB at this address has already been mapped.`start_xen` calls this = twice, + * before and after `setup_page_tables`, which is a no-op on MPU. + */ + if ( mapped_fdt_base =3D=3D fdt_paddr ) + return fdt_virt; + + ASSERT(mapped_fdt_base =3D=3D INVALID_PADDR); + + nr_mfns =3D (limit - base) >> PAGE_SHIFT; + + rc =3D map_pages_to_xen(base, maddr_to_mfn(base), nr_mfns, flags); + if ( rc ) + panic("Unable to map the device-tree\n"); + + mapped_fdt_base =3D fdt_paddr; + mapped_fdt_limit =3D limit; + + if ( fdt_magic(fdt_virt) !=3D FDT_MAGIC ) + return NULL; + + size =3D fdt_totalsize(fdt_virt); + if ( size > MAX_FDT_SIZE ) + return NULL; + + limit =3D round_pgup(fdt_paddr + size); + + /* If the mapped range is not enough, map the rest of the DTB. */ + if ( limit > mapped_fdt_limit ) + { + rc =3D destroy_xen_mappings(base, mapped_fdt_limit); + if ( rc ) + panic("Unable to unmap the device-tree header\n"); + + nr_mfns =3D (limit - base) >> PAGE_SHIFT; + + rc =3D map_pages_to_xen(base, maddr_to_mfn(base), nr_mfns, flags); + if ( rc ) + panic("Unable to map the device-tree\n"); + + mapped_fdt_limit =3D limit; + } + + return fdt_virt; } =20 /* --=20 2.34.1 From nobody Thu Oct 30 22:49:05 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) client-ip=192.237.175.120; envelope-from=xen-devel-bounces@lists.xenproject.org; helo=lists.xenproject.org; Authentication-Results: mx.zohomail.com; spf=pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org; dmarc=fail(p=none dis=none) header.from=arm.com Return-Path: Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) by mx.zohomail.com with SMTPS id 1753086773357180.94844342454098; Mon, 21 Jul 2025 01:32:53 -0700 (PDT) Received: from list by lists.xenproject.org with outflank-mailman.1051168.1419481 (Exim 4.92) (envelope-from ) id 1udlwx-0007hT-Ig; Mon, 21 Jul 2025 08:32:43 +0000 Received: by outflank-mailman (output) from mailman id 1051168.1419481; Mon, 21 Jul 2025 08:32:43 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1udlwx-0007hG-FY; Mon, 21 Jul 2025 08:32:43 +0000 Received: by outflank-mailman (input) for mailman id 1051168; Mon, 21 Jul 2025 08:32:42 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1udlwv-0005OI-Vp for xen-devel@lists.xenproject.org; Mon, 21 Jul 2025 08:32:41 +0000 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by se1-gles-flk1.inumbo.com (Halon) with ESMTP id 437db7ed-660d-11f0-b894-0df219b8e170; Mon, 21 Jul 2025 10:32:40 +0200 (CEST) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id B6E02153B; Mon, 21 Jul 2025 01:32:33 -0700 (PDT) Received: from PWQ0QT7DJ1.arm.com (unknown [10.57.71.32]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 4643C3F66E; Mon, 21 Jul 2025 01:32:38 -0700 (PDT) X-Outflank-Mailman: Message body and most headers restored to incoming version X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 437db7ed-660d-11f0-b894-0df219b8e170 From: Hari Limaye To: xen-devel@lists.xenproject.org Cc: luca.fancellu@arm.com, Stefano Stabellini , Julien Grall , Bertrand Marquis , Michal Orzel , Volodymyr Babchuk Subject: [PATCH v4 6/6] arm/mpu: Implement remove_early_mappings for MPU systems Date: Mon, 21 Jul 2025 09:31:47 +0100 Message-ID: X-Mailer: git-send-email 2.42.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ZM-MESSAGEID: 1753086774605116600 Content-Type: text/plain; charset="utf-8" From: Luca Fancellu Implement remove_early_mappings for MPU systems. Signed-off-by: Luca Fancellu Signed-off-by: Hari Limaye Reviewed-by: Michal Orzel --- Changes from v1: - Add Ayan's R-b Changes from v2: - Remove full stop - Remove sanity check for `mapped_fdt_paddr =3D=3D INVALID_PADDR` Changes from v3: - Drop Ayan's R-b - Add Michals's R-b --- xen/arch/arm/mpu/setup.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/xen/arch/arm/mpu/setup.c b/xen/arch/arm/mpu/setup.c index 2ef703757f..163573b932 100644 --- a/xen/arch/arm/mpu/setup.c +++ b/xen/arch/arm/mpu/setup.c @@ -96,7 +96,11 @@ void __init copy_from_paddr(void *dst, paddr_t paddr, un= signed long len) =20 void __init remove_early_mappings(void) { - BUG_ON("unimplemented"); + int rc =3D destroy_xen_mappings(round_pgdown(mapped_fdt_base), + mapped_fdt_limit); + + if ( rc ) + panic("Unable to unmap the device-tree\n"); } =20 /* --=20 2.34.1