__vdso_sgx_enter_enclave() gets another rewrite, this time to strip it down to the bare minimum and explicitly break compliance with the x86-64 ABI. Feedback from v4 revealed that __vdso_sgx_enter_enclave() would need to save (a lot) more than just the non-volatile GPRs to be compliant with the x86-64 ABI, at which point breaking from the ABI completely became much more palatable. The non-standard ABI also solves the question of "which GPRs should be marshalled to/from the enclave" by getting out of the way entirely and letting userspace have free reign (except for RSP, which has a big ol' DO NOT TOUCH sign on it). [1] https://lkml.kernel.org/r/cda13cff-1a56-a40f-7d69-f0f1ab752f8e@xxxxxxxxxxxx v1: https://lkml.kernel.org/r/20181205232012.28920-1-sean.j.christopherson@xxxxxxxxx v2: https://lkml.kernel.org/r/20181206221922.31012-1-sean.j.christopherson@xxxxxxxxx v3: https://lkml.kernel.org/r/20181210232141.5425-1-sean.j.christopherson@xxxxxxxxx v4: https://lkml.kernel.org/r/20181213213135.12913-1-sean.j.christopherson@xxxxxxxxx v5: - Strip down __vdso_sgx_enter_enclave() so it only touches RSP and GPRs that are already collateral damage of ENCLU[EENTER/ERESUME]. - Add a 16-byte reserved field to 'struct sgx_enclave_exception' so the struct can grow in a backwards compatible fashion. - Add a blurb at the end of the changelog for patch 1/5 explaining why the vDSO fixup macros look different than the equivalent kernel macros. Sean Christopherson (5): x86/vdso: Add support for exception fixup in vDSO functions x86/fault: Add helper function to sanitize error code x86/fault: Attempt to fixup unhandled #PF on ENCLU before signaling x86/traps: Attempt to fixup exceptions in vDSO before signaling x86/vdso: Add __vdso_sgx_enter_enclave() to wrap SGX enclave transitions arch/x86/entry/vdso/Makefile | 6 +- arch/x86/entry/vdso/extable.c | 37 +++++++++ arch/x86/entry/vdso/extable.h | 29 +++++++ arch/x86/entry/vdso/vdso-layout.lds.S | 9 ++- arch/x86/entry/vdso/vdso.lds.S | 1 + arch/x86/entry/vdso/vdso2c.h | 58 ++++++++++++-- arch/x86/entry/vdso/vsgx_enter_enclave.S | 97 ++++++++++++++++++++++++ arch/x86/include/asm/vdso.h | 5 ++ arch/x86/include/uapi/asm/sgx.h | 18 +++++ arch/x86/kernel/traps.c | 14 ++++ arch/x86/mm/fault.c | 33 +++++--- 11 files changed, 284 insertions(+), 23 deletions(-) create mode 100644 arch/x86/entry/vdso/extable.c create mode 100644 arch/x86/entry/vdso/extable.h create mode 100644 arch/x86/entry/vdso/vsgx_enter_enclave.S -- 2.19.2
