From: "tip-bot2 for Ira Weiny" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: Ira Weiny <ira.weiny@intel.com>, Borislav Petkov <bp@suse.de>,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: [tip: x86/sgx] x86/sgx: Remove unnecessary kmap() from sgx_ioc_enclave_init()
Date: Thu, 25 Mar 2021 09:07:53 -0000 [thread overview]
Message-ID: <161666327367.398.13497317317824782755.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20210324182246.2484875-1-ira.weiny@intel.com>
The following commit has been merged into the x86/sgx branch of tip:
Commit-ID: 633b0616cfe085679471a4c0fae02e8c3a1a9866
Gitweb: https://git.kernel.org/tip/633b0616cfe085679471a4c0fae02e8c3a1a9866
Author: Ira Weiny <ira.weiny@intel.com>
AuthorDate: Wed, 24 Mar 2021 11:22:46 -07:00
Committer: Borislav Petkov <bp@suse.de>
CommitterDate: Thu, 25 Mar 2021 09:50:32 +01:00
x86/sgx: Remove unnecessary kmap() from sgx_ioc_enclave_init()
kmap() is inefficient and is being replaced by kmap_local_page(), if
possible. There is no readily apparent reason why initp_page needs to be
allocated and kmap'ed() except that 'sigstruct' needs to be page-aligned
and 'token' 512 byte-aligned.
Rather than change it to kmap_local_page(), use kmalloc() instead
because kmalloc() can give this alignment when allocating PAGE_SIZE
bytes.
Remove the alloc_page()/kmap() and replace with kmalloc(PAGE_SIZE, ...)
to get a page aligned kernel address.
In addition, add a comment to document the alignment requirements so that
others don't attempt to 'fix' this again.
[ bp: Massage commit message. ]
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210324182246.2484875-1-ira.weiny@intel.com
---
arch/x86/kernel/cpu/sgx/ioctl.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)
diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
index 90a5caf..2e10367 100644
--- a/arch/x86/kernel/cpu/sgx/ioctl.c
+++ b/arch/x86/kernel/cpu/sgx/ioctl.c
@@ -604,7 +604,6 @@ static long sgx_ioc_enclave_init(struct sgx_encl *encl, void __user *arg)
{
struct sgx_sigstruct *sigstruct;
struct sgx_enclave_init init_arg;
- struct page *initp_page;
void *token;
int ret;
@@ -615,11 +614,15 @@ static long sgx_ioc_enclave_init(struct sgx_encl *encl, void __user *arg)
if (copy_from_user(&init_arg, arg, sizeof(init_arg)))
return -EFAULT;
- initp_page = alloc_page(GFP_KERNEL);
- if (!initp_page)
+ /*
+ * 'sigstruct' must be on a page boundary and 'token' on a 512 byte
+ * boundary. kmalloc() will give this alignment when allocating
+ * PAGE_SIZE bytes.
+ */
+ sigstruct = kmalloc(PAGE_SIZE, GFP_KERNEL);
+ if (!sigstruct)
return -ENOMEM;
- sigstruct = kmap(initp_page);
token = (void *)((unsigned long)sigstruct + PAGE_SIZE / 2);
memset(token, 0, SGX_LAUNCH_TOKEN_SIZE);
@@ -645,8 +648,7 @@ static long sgx_ioc_enclave_init(struct sgx_encl *encl, void __user *arg)
ret = sgx_encl_init(encl, sigstruct, token);
out:
- kunmap(initp_page);
- __free_page(initp_page);
+ kfree(sigstruct);
return ret;
}
next prev parent reply other threads:[~2021-03-25 9:08 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-24 18:22 [PATCH] x86/sgx: Remove unnecessary kmap() from sgx_ioc_enclave_init() ira.weiny
2021-03-25 9:07 ` tip-bot2 for Ira Weiny [this message]
2021-03-26 19:45 ` Jarkko Sakkinen
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