[PATCH] x86/sgx: Replace kmap/kunmap_atomic calls

From: Kristen Carlson Accardi
Date: Thu Sep 29 2022 - 12:08:07 EST


It is not necessary to disable page faults or preemption when
using kmap calls, so replace kmap_atomic() and kunmap_atomic()
calls with more the more appropriate kmap_local_page() and
kunmap_local() calls.

Signed-off-by: Kristen Carlson Accardi <kristen@xxxxxxxxxxxxxxx>
---
arch/x86/kernel/cpu/sgx/encl.c | 12 ++++++------
arch/x86/kernel/cpu/sgx/ioctl.c | 4 ++--
arch/x86/kernel/cpu/sgx/main.c | 8 ++++----
3 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c
index f40d64206ded..63dd92bd3288 100644
--- a/arch/x86/kernel/cpu/sgx/encl.c
+++ b/arch/x86/kernel/cpu/sgx/encl.c
@@ -160,8 +160,8 @@ static int __sgx_encl_eldu(struct sgx_encl_page *encl_page,
return ret;

pginfo.addr = encl_page->desc & PAGE_MASK;
- pginfo.contents = (unsigned long)kmap_atomic(b.contents);
- pcmd_page = kmap_atomic(b.pcmd);
+ pginfo.contents = (unsigned long)kmap_local_page(b.contents);
+ pcmd_page = kmap_local_page(b.pcmd);
pginfo.metadata = (unsigned long)pcmd_page + b.pcmd_offset;

if (secs_page)
@@ -187,8 +187,8 @@ static int __sgx_encl_eldu(struct sgx_encl_page *encl_page,
*/
pcmd_page_empty = !memchr_inv(pcmd_page, 0, PAGE_SIZE);

- kunmap_atomic(pcmd_page);
- kunmap_atomic((void *)(unsigned long)pginfo.contents);
+ kunmap_local(pcmd_page);
+ kunmap_local((void *)(unsigned long)pginfo.contents);

get_page(b.pcmd);
sgx_encl_put_backing(&b);
@@ -197,10 +197,10 @@ static int __sgx_encl_eldu(struct sgx_encl_page *encl_page,

if (pcmd_page_empty && !reclaimer_writing_to_pcmd(encl, pcmd_first_page)) {
sgx_encl_truncate_backing_page(encl, PFN_DOWN(page_pcmd_off));
- pcmd_page = kmap_atomic(b.pcmd);
+ pcmd_page = kmap_local_page(b.pcmd);
if (memchr_inv(pcmd_page, 0, PAGE_SIZE))
pr_warn("PCMD page not empty after truncate.\n");
- kunmap_atomic(pcmd_page);
+ kunmap_local(pcmd_page);
}

put_page(b.pcmd);
diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
index ebe79d60619f..f2f918b8b9b1 100644
--- a/arch/x86/kernel/cpu/sgx/ioctl.c
+++ b/arch/x86/kernel/cpu/sgx/ioctl.c
@@ -221,11 +221,11 @@ static int __sgx_encl_add_page(struct sgx_encl *encl,
pginfo.secs = (unsigned long)sgx_get_epc_virt_addr(encl->secs.epc_page);
pginfo.addr = encl_page->desc & PAGE_MASK;
pginfo.metadata = (unsigned long)secinfo;
- pginfo.contents = (unsigned long)kmap_atomic(src_page);
+ pginfo.contents = (unsigned long)kmap_local_page(src_page);

ret = __eadd(&pginfo, sgx_get_epc_virt_addr(epc_page));

- kunmap_atomic((void *)pginfo.contents);
+ kunmap_local((void *)pginfo.contents);
put_page(src_page);

return ret ? -EIO : 0;
diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
index 515e2a5f25bb..4efda5e8cadf 100644
--- a/arch/x86/kernel/cpu/sgx/main.c
+++ b/arch/x86/kernel/cpu/sgx/main.c
@@ -159,17 +159,17 @@ static int __sgx_encl_ewb(struct sgx_epc_page *epc_page, void *va_slot,
pginfo.addr = 0;
pginfo.secs = 0;

- pginfo.contents = (unsigned long)kmap_atomic(backing->contents);
- pginfo.metadata = (unsigned long)kmap_atomic(backing->pcmd) +
+ pginfo.contents = (unsigned long)kmap_local_page(backing->contents);
+ pginfo.metadata = (unsigned long)kmap_local_page(backing->pcmd) +
backing->pcmd_offset;

ret = __ewb(&pginfo, sgx_get_epc_virt_addr(epc_page), va_slot);
set_page_dirty(backing->pcmd);
set_page_dirty(backing->contents);

- kunmap_atomic((void *)(unsigned long)(pginfo.metadata -
+ kunmap_local((void *)(unsigned long)(pginfo.metadata -
backing->pcmd_offset));
- kunmap_atomic((void *)(unsigned long)pginfo.contents);
+ kunmap_local((void *)(unsigned long)pginfo.contents);

return ret;
}
--
2.37.3