[RFC 03/12] syscall/x86: Wire up a new system call for memory encryption keys

[Alison Schofield]

encrypt_mprotect() is a new system call to support memory encryption.

It takes the same parameters as legacy mprotect, plus an additional
key serial number that is mapped to an encryption keyid.

Signed-off-by: Alison Schofield <alison.schofield at intel.com>
---
 arch/x86/entry/syscalls/syscall_32.tbl | 1 +
 arch/x86/entry/syscalls/syscall_64.tbl | 1 +
 include/linux/syscalls.h               | 2 ++
 include/uapi/asm-generic/unistd.h      | 4 +++-
 kernel/sys_ni.c                        | 2 ++
 5 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index 3cf7b533b3d1..f41ad857d5c6 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -398,3 +398,4 @@
 384	i386	arch_prctl		sys_arch_prctl			__ia32_compat_sys_arch_prctl
 385	i386	io_pgetevents		sys_io_pgetevents		__ia32_compat_sys_io_pgetevents
 386	i386	rseq			sys_rseq			__ia32_sys_rseq
+387	i386	encrypt_mprotect	sys_encrypt_mprotect		__ia32_sys_encrypt_mprotect
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index f0b1709a5ffb..cf2decfa6119 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -343,6 +343,7 @@
 332	common	statx			__x64_sys_statx
 333	common	io_pgetevents		__x64_sys_io_pgetevents
 334	common	rseq			__x64_sys_rseq
+335	common	encrypt_mprotect	__x64_sys_encrypt_mprotect
 
 #
 # x32-specific system call numbers start at 512 to avoid cache impact
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 3ed377d0c46c..7dc0ed3a182e 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -904,6 +904,8 @@ asmlinkage long sys_statx(int dfd, const char __user *path, unsigned flags,
 			  unsigned mask, struct statx __user *buffer);
 asmlinkage long sys_rseq(struct rseq __user *rseq, uint32_t rseq_len,
 			 int flags, uint32_t sig);
+asmlinkage long sys_encrypt_mprotect(unsigned long start, size_t len,
+				     unsigned long prot, int serial);
 
 /*
  * Architecture-specific system calls
diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
index 42990676a55e..d2cb0af68160 100644
--- a/include/uapi/asm-generic/unistd.h
+++ b/include/uapi/asm-generic/unistd.h
@@ -734,9 +734,11 @@ __SYSCALL(__NR_pkey_free,     sys_pkey_free)
 __SYSCALL(__NR_statx,     sys_statx)
 #define __NR_io_pgetevents 292
 __SC_COMP(__NR_io_pgetevents, sys_io_pgetevents, compat_sys_io_pgetevents)
+#define __NR_encrypt_mprotect 293
+__SYSCALL(__NR_encrypt_mprotect, sys_encrypt_mprotect)
 
 #undef __NR_syscalls
-#define __NR_syscalls 293
+#define __NR_syscalls 294
 
 /*
  * 32 bit systems traditionally used different
diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
index df556175be50..1b48f709c265 100644
--- a/kernel/sys_ni.c
+++ b/kernel/sys_ni.c
@@ -336,6 +336,8 @@ COND_SYSCALL(pkey_mprotect);
 COND_SYSCALL(pkey_alloc);
 COND_SYSCALL(pkey_free);
 
+/* multi-key total memory encryption keys */
+COND_SYSCALL(encrypt_mprotect);
 
 /*
  * Architecture specific weak syscall entries.
-- 
2.14.1