From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: linux-kernel@vger.kernel.org, x86@kernel.org, linux-sgx@vger.kernel.org
Cc: akpm@linux-foundation.org, dave.hansen@intel.com,
sean.j.christopherson@intel.com, nhorman@redhat.com,
npmccallum@redhat.com, serge.ayoun@intel.com,
shay.katz-zamir@intel.com, haitao.huang@intel.com,
andriy.shevchenko@linux.intel.com, tglx@linutronix.de,
kai.svahn@intel.com, bp@alien8.de, josh@joshtriplett.org,
luto@kernel.org, kai.huang@intel.com, rientjes@google.com,
Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Subject: [PATCH v19,RESEND 14/27] x86/sgx: Add functions to allocate and free EPC pages
Date: Wed, 20 Mar 2019 18:21:06 +0200 [thread overview]
Message-ID: <20190320162119.4469-15-jarkko.sakkinen@linux.intel.com> (raw)
In-Reply-To: <20190320162119.4469-1-jarkko.sakkinen@linux.intel.com>
At this time there is no support for reclaiming pages prior to the
owner explicitly freeing the page. As for freeing pages, because
freeing a page is expected to succeed in the vast majority of cases
and because most call sites will not be equipped to handle failure,
provide a variant for freeing a page that warns on failure, e.g. due
to ENCLS[EREMOVE] failing.
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Co-developed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
arch/x86/kernel/cpu/sgx/main.c | 89 ++++++++++++++++++++++++++++++++++
arch/x86/kernel/cpu/sgx/sgx.h | 4 ++
2 files changed, 93 insertions(+)
diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
index 18ce4acdd7ef..f88c8d86c2a8 100644
--- a/arch/x86/kernel/cpu/sgx/main.c
+++ b/arch/x86/kernel/cpu/sgx/main.c
@@ -9,6 +9,7 @@
#include <linux/sched/signal.h>
#include <linux/slab.h>
#include "arch.h"
+#include "encls.h"
#include "sgx.h"
struct sgx_epc_section sgx_epc_sections[SGX_MAX_EPC_SECTIONS];
@@ -23,6 +24,94 @@ static void sgx_section_put_page(struct sgx_epc_section *section,
section->free_cnt++;
}
+static struct sgx_epc_page *sgx_section_get_page(
+ struct sgx_epc_section *section)
+{
+ struct sgx_epc_page *page;
+
+ if (!section->free_cnt)
+ return NULL;
+
+ page = list_first_entry(§ion->page_list,
+ struct sgx_epc_page, list);
+ list_del_init(&page->list);
+ section->free_cnt--;
+ return page;
+}
+
+/**
+ * sgx_alloc_page - Allocate an EPC page
+ *
+ * Try to grab a page from the free EPC page list.
+ *
+ * Return:
+ * a pointer to a &struct sgx_epc_page instance,
+ * -errno on error
+ */
+struct sgx_epc_page *sgx_alloc_page(void)
+{
+ struct sgx_epc_section *section;
+ struct sgx_epc_page *page;
+ int i;
+
+ for (i = 0; i < sgx_nr_epc_sections; i++) {
+ section = &sgx_epc_sections[i];
+ spin_lock(§ion->lock);
+ page = sgx_section_get_page(section);
+ spin_unlock(§ion->lock);
+
+ if (page)
+ return page;
+ }
+
+ return ERR_PTR(-ENOMEM);
+}
+EXPORT_SYMBOL_GPL(sgx_alloc_page);
+
+/**
+ * __sgx_free_page - Free an EPC page
+ * @page: pointer a previously allocated EPC page
+ *
+ * EREMOVE an EPC page and insert it back to the list of free pages.
+ *
+ * Return:
+ * 0 on success
+ * SGX error code if EREMOVE fails
+ */
+int __sgx_free_page(struct sgx_epc_page *page)
+{
+ struct sgx_epc_section *section = sgx_epc_section(page);
+ int ret;
+
+ ret = __eremove(sgx_epc_addr(page));
+ if (ret)
+ return ret;
+
+ spin_lock(§ion->lock);
+ sgx_section_put_page(section, page);
+ spin_unlock(§ion->lock);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(__sgx_free_page);
+
+/**
+ * sgx_free_page - Free an EPC page and WARN on failure
+ * @page: pointer to a previously allocated EPC page
+ *
+ * EREMOVE an EPC page and insert it back to the list of free pages, and WARN
+ * if EREMOVE fails. For use when the call site cannot (or chooses not to)
+ * handle failure, i.e. the page is leaked on failure.
+ */
+void sgx_free_page(struct sgx_epc_page *page)
+{
+ int ret;
+
+ ret = __sgx_free_page(page);
+ WARN(ret > 0, "sgx: EREMOVE returned %d (0x%x)", ret, ret);
+}
+EXPORT_SYMBOL_GPL(sgx_free_page);
+
static __init void sgx_free_epc_section(struct sgx_epc_section *section)
{
struct sgx_epc_page *page;
diff --git a/arch/x86/kernel/cpu/sgx/sgx.h b/arch/x86/kernel/cpu/sgx/sgx.h
index 228e3dae360d..86b4c74b6089 100644
--- a/arch/x86/kernel/cpu/sgx/sgx.h
+++ b/arch/x86/kernel/cpu/sgx/sgx.h
@@ -59,4 +59,8 @@ static inline void *sgx_epc_addr(struct sgx_epc_page *page)
return section->va + (page->desc & PAGE_MASK) - section->pa;
}
+struct sgx_epc_page *sgx_alloc_page(void);
+int __sgx_free_page(struct sgx_epc_page *page);
+void sgx_free_page(struct sgx_epc_page *page);
+
#endif /* _X86_SGX_H */
--
2.19.1
next prev parent reply other threads:[~2019-03-20 16:24 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-20 16:20 [PATCH v19,RESEND 00/27] Intel SGX1 support Jarkko Sakkinen
2019-03-20 16:20 ` [PATCH v19,RESEND 01/27] x86/cpufeatures: Add Intel-defined SGX feature bit Jarkko Sakkinen
2019-03-20 19:41 ` Neil Horman
2019-03-21 14:16 ` Jarkko Sakkinen
2019-03-20 16:20 ` [PATCH v19,RESEND 02/27] x86/cpufeatures: Add SGX sub-features (as Linux-defined bits) Jarkko Sakkinen
2019-03-20 16:20 ` [PATCH v19,RESEND 03/27] x86/msr: Add IA32_FEATURE_CONTROL.SGX_ENABLE definition Jarkko Sakkinen
2019-03-20 16:20 ` [PATCH v19,RESEND 04/27] x86/cpufeatures: Add Intel-defined SGX_LC feature bit Jarkko Sakkinen
2019-03-20 16:20 ` [PATCH v19,RESEND 05/27] x86/msr: Add SGX Launch Control MSR definitions Jarkko Sakkinen
2019-03-20 16:20 ` [PATCH v19,RESEND 06/27] x86/mm: x86/sgx: Add new 'PF_SGX' page fault error code bit Jarkko Sakkinen
2019-03-20 16:20 ` [PATCH v19,RESEND 07/27] x86/mm: x86/sgx: Signal SIGSEGV for userspace #PFs w/ PF_SGX Jarkko Sakkinen
2019-03-20 16:21 ` [PATCH v19,RESEND 08/27] x86/cpu/intel: Detect SGX support and update caps appropriately Jarkko Sakkinen
2019-03-26 12:17 ` Huang, Kai
2019-03-26 14:27 ` Sean Christopherson
2019-03-26 21:25 ` Huang, Kai
2019-03-26 21:57 ` Sean Christopherson
2019-03-26 23:19 ` Huang, Kai
2019-03-20 16:21 ` [PATCH v19,RESEND 09/27] x86/sgx: Add ENCLS architectural error codes Jarkko Sakkinen
2019-03-20 16:21 ` [PATCH v19,RESEND 10/27] x86/sgx: Add SGX1 and SGX2 architectural data structures Jarkko Sakkinen
2019-03-20 16:21 ` [PATCH v19,RESEND 11/27] x86/sgx: Add definitions for SGX's CPUID leaf and variable sub-leafs Jarkko Sakkinen
2019-03-20 16:21 ` [PATCH v19,RESEND 12/27] x86/sgx: Enumerate and track EPC sections Jarkko Sakkinen
2019-03-20 16:21 ` [PATCH v19,RESEND 13/27] x86/sgx: Add wrappers for ENCLS leaf functions Jarkko Sakkinen
2019-03-20 16:21 ` Jarkko Sakkinen [this message]
2019-03-20 16:21 ` [PATCH v19,RESEND 15/27] x86/sgx: Add sgx_einit() for initializing enclaves Jarkko Sakkinen
2019-03-20 16:21 ` [PATCH v19,RESEND 16/27] x86/sgx: Add the Linux SGX Enclave Driver Jarkko Sakkinen
2019-03-26 12:01 ` Huang, Kai
2019-03-26 12:40 ` Thomas Gleixner
2019-03-26 14:54 ` Sean Christopherson
2019-03-26 21:11 ` Huang, Kai
2019-03-27 5:02 ` Jarkko Sakkinen
2019-03-20 16:21 ` [PATCH v19,RESEND 17/27] x86/sgx: Add provisioning Jarkko Sakkinen
2019-03-20 16:21 ` [PATCH v19,RESEND 18/27] x86/sgx: Add swapping code to the core and SGX driver Jarkko Sakkinen
2019-03-20 16:21 ` [PATCH v19,RESEND 19/27] x86/sgx: ptrace() support for the " Jarkko Sakkinen
2019-03-20 16:21 ` [PATCH v19,RESEND 20/27] x86/vdso: Add support for exception fixup in vDSO functions Jarkko Sakkinen
2019-03-20 16:21 ` [PATCH v19,RESEND 21/27] x86/fault: Add helper function to sanitize error code Jarkko Sakkinen
2019-03-20 16:21 ` [PATCH v19,RESEND 22/27] x86/fault: Attempt to fixup unhandled #PF in vDSO before signaling Jarkko Sakkinen
2019-03-20 16:21 ` [PATCH v19,RESEND 23/27] x86/traps: Attempt to fixup exceptions " Jarkko Sakkinen
2019-03-20 16:21 ` [PATCH v19,RESEND 24/27] x86/vdso: Add __vdso_sgx_enter_enclave() to wrap SGX enclave transitions Jarkko Sakkinen
2019-03-20 18:30 ` Xing, Cedric
2019-03-20 18:52 ` Andy Lutomirski
2019-03-20 19:57 ` Xing, Cedric
2019-03-20 21:03 ` Sean Christopherson
2019-03-21 0:17 ` Xing, Cedric
2019-03-22 21:20 ` Sean Christopherson
2019-03-21 17:17 ` Andy Lutomirski
2019-03-22 20:31 ` Xing, Cedric
2019-03-20 19:02 ` Jethro Beekman
2019-03-20 20:10 ` Xing, Cedric
2019-03-20 19:13 ` Sean Christopherson
2019-03-20 20:38 ` Xing, Cedric
2019-03-22 21:59 ` Sean Christopherson
2019-03-23 17:36 ` Xing, Cedric
2019-03-23 21:38 ` Andy Lutomirski
2019-03-24 8:59 ` Xing, Cedric
2019-03-25 18:03 ` Sean Christopherson
2019-03-25 23:59 ` Andy Lutomirski
2019-03-26 4:53 ` Xing, Cedric
2019-03-26 17:08 ` Andy Lutomirski
2019-03-28 4:23 ` Xing, Cedric
2019-03-28 19:18 ` Andy Lutomirski
2019-03-28 23:19 ` Xing, Cedric
2019-03-29 9:48 ` Jarkko Sakkinen
2019-03-31 8:43 ` Dr. Greg
2019-04-03 23:03 ` Sean Christopherson
2019-03-25 23:54 ` Andy Lutomirski
2019-03-26 4:16 ` Xing, Cedric
2019-03-20 16:21 ` [PATCH v19,RESEND 25/27] x86/sgx: SGX documentation Jarkko Sakkinen
2019-03-20 16:21 ` [PATCH v19,RESEND 26/27] selftests/x86: Add a selftest for SGX Jarkko Sakkinen
2019-03-20 16:21 ` [PATCH v19,RESEND 27/27] x86/sgx: Update MAINTAINERS Jarkko Sakkinen
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