Rework __vdso_sgx_enter_enclave() to move all input/output params, except
for pass-through GPRs, into a single struct. With the new struct, add
two new features (requested by Nathaniel and Jethro), and fix a
long-standing nit (from Andy).
1. Add an opaque param to pass data from the runtime to its handler.
https://lkml.kernel.org/r/CAOASepOFh-vOrNZEVDFrDSuHs+9GEzzpXUTG-fZMuyjWAkpRWw@xxxxxxxxxxxxxx
2. Allow the runtime to exit the vDSO on interrupts, e.g. for context
switching when doing M:N scheduling of enclave threads.
https://lkml.kernel.org/r/dcebec2e-ea46-48ec-e49b-292b10282373@xxxxxxxxxxxx
3. Use a dedicated exit reason instead of using -EFAULT for "exception"
(and effectively -EINTR for interrupts, too).
https://lkml.kernel.org/r/90D05734-1583-4306-A9A4-18E4A1390F3B@xxxxxxxxxxxxxx
Patch 1 is a bug fix I found by inspection when reworking the code.
Reworking so much of the code this late in the game is a bit scary, but
the alternative is massive param lists for both the vDSO and the handler,
especially if we add both a flags param and an opaque pointer. And IMO,
the result is also a tiny bit cleaner than what we have today, even
without adding @flags and @opaque.
typedef int (*vdso_sgx_enter_enclave_t)(unsigned long rdi, unsigned long rsi,
unsigned long rdx, unsigned int leaf,
unsigned long r8, unsigned long r9,
struct sgx_enclave_run *r);
typedef int (*sgx_enclave_exit_handler_t)(long rdi, long rsi, long rdx,
long ursp, long r8, long r9,
struct sgx_enclave_run *r);
vs.
typedef int (*vdso_sgx_enter_enclave_t)(unsigned long rdi, unsigned long rsi,
unsigned long rdx, unsigned int leaf,
unsigned long r8, unsigned long r9,
void *tcs,
struct sgx_enclave_exception *e,
sgx_enclave_exit_handler_t handler,
unsigned long flags,
unsigned long opaque);
typedef int (*sgx_enclave_exit_handler_t)(long rdi, long rsi, long rdx,
long ursp, long r8, long r9,
void *tcs, int ret,
struct sgx_enclave_exception *e,
unsigned long opaque);
Sean Christopherson (4):
x86/vdso: x86/sgx: Explicitly force 8-byte CMP for detecting user
handler
x86/vdso: x86/sgx: Rework __vdso_sgx_enter_enclave() API
x86/vdso: x86/sgx: Introduce dedicated SGX exit reasons for vDSO
x86/vdso: x86/sgx: Allow the user to exit the vDSO loop on interrupts
arch/x86/entry/vdso/vsgx_enter_enclave.S | 94 +++++++++++++++++------
arch/x86/include/uapi/asm/sgx.h | 96 ++++++++++++++++--------
2 files changed, 135 insertions(+), 55 deletions(-)
--
2.28.0
