linux.git/tools/testing/selftests/sgx, branch v6.9 Linux kernel source tree selftests/sgx: Skip non X86_64 platform 2023-12-08T18:08:17+00:00 Zhao Mengmeng zhaomengmeng@kylinos.cn 2023-12-06T02:56:05+00:00 981cf568a8644161c2f15c02278ebc2834b51ba6 When building whole selftests on arm64, rsync gives an erorr about sgx: rsync: [sender] link_stat "/root/linux-next/tools/testing/selftests/sgx/test_encl.elf" failed: No such file or directory (2) rsync error: some files/attrs were not transferred (see previous errors) (code 23) at main.c(1327) [sender=3.2.5] The root casue is sgx only used on X86_64, and shall be skipped on other platforms. Fix this by moving TEST_CUSTOM_PROGS and TEST_FILES inside the if check, then the build result will be "Skipping non-existent dir: sgx". Fixes: 2adcba79e69d ("selftests/x86: Add a selftest for SGX") Signed-off-by: Zhao Mengmeng <zhaomengmeng@kylinos.cn> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> Link: https://lore.kernel.org/all/20231206025605.3965302-1-zhaomzhao%40126.com 
When building whole selftests on arm64, rsync gives an erorr about sgx:

rsync: [sender] link_stat "/root/linux-next/tools/testing/selftests/sgx/test_encl.elf" failed: No such file or directory (2)
rsync error: some files/attrs were not transferred (see previous errors) (code 23) at main.c(1327) [sender=3.2.5]

The root casue is sgx only used on X86_64, and shall be skipped on other
platforms.

Fix this by moving TEST_CUSTOM_PROGS and TEST_FILES inside the if check,
then the build result will be "Skipping non-existent dir: sgx".

Fixes: 2adcba79e69d ("selftests/x86: Add a selftest for SGX")
Signed-off-by: Zhao Mengmeng <zhaomengmeng@kylinos.cn>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Link: https://lore.kernel.org/all/20231206025605.3965302-1-zhaomzhao%40126.com
selftests/sgx: Remove incomplete ABI sanitization code in test enclave 2023-12-08T18:05:28+00:00 Jo Van Bulck jo.vanbulck@cs.kuleuven.be 2023-10-05T15:38:54+00:00 886c5be0b12e89b2905c26c4f24d50ae91f261da As the selftest enclave is *not* intended for production, simplify the code by not initializing CPU configuration registers as expected by the ABI on enclave entry or cleansing caller-save registers on enclave exit. Signed-off-by: Jo Van Bulck <jo.vanbulck@cs.kuleuven.be> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> Link: https://lore.kernel.org/all/da0cfb1e-e347-f7f2-ac72-aec0ee0d867d@intel.com/ Link: https://lore.kernel.org/all/20231005153854.25566-14-jo.vanbulck%40cs.kuleuven.be 
As the selftest enclave is *not* intended for production, simplify the
code by not initializing CPU configuration registers as expected by the
ABI on enclave entry or cleansing caller-save registers on enclave exit.

Signed-off-by: Jo Van Bulck <jo.vanbulck@cs.kuleuven.be>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Link: https://lore.kernel.org/all/da0cfb1e-e347-f7f2-ac72-aec0ee0d867d@intel.com/
Link: https://lore.kernel.org/all/20231005153854.25566-14-jo.vanbulck%40cs.kuleuven.be
selftests/sgx: Discard unsupported ELF sections 2023-12-08T18:05:28+00:00 Jo Van Bulck jo.vanbulck@cs.kuleuven.be 2023-10-05T15:38:53+00:00 ec44ca1e34bc3a9864a8c1bf8636066ec6d5d2e5 Building the test enclave with -static-pie may produce a dynamic symbol table, but this is not supported for enclaves and any relocations need to happen manually (e.g., as for "encl_op_array"). Thus, opportunistically discard ".dyn*" and ".gnu.hash" which the enclave loader cannot handle. Signed-off-by: Jo Van Bulck <jo.vanbulck@cs.kuleuven.be> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> Link: https://lore.kernel.org/all/20231005153854.25566-13-jo.vanbulck%40cs.kuleuven.be 
Building the test enclave with -static-pie may produce a dynamic symbol
table, but this is not supported for enclaves and any relocations need to
happen manually (e.g., as for "encl_op_array"). Thus, opportunistically
discard ".dyn*" and ".gnu.hash" which the enclave loader cannot handle.

Signed-off-by: Jo Van Bulck <jo.vanbulck@cs.kuleuven.be>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Link: https://lore.kernel.org/all/20231005153854.25566-13-jo.vanbulck%40cs.kuleuven.be
selftests/sgx: Ensure expected location of test enclave buffer 2023-12-08T18:05:27+00:00 Jo Van Bulck jo.vanbulck@cs.kuleuven.be 2023-10-05T15:38:52+00:00 022416496008bd51cb7b33975cc0008749329a86 The external tests manipulating page permissions expect encl_buffer to be placed at the start of the test enclave's .data section. As this is not guaranteed per the C standard, explicitly place encl_buffer in a separate section that is explicitly placed at the start of the .data segment in the linker script to avoid the compiler placing it somewhere else in .data. Signed-off-by: Jo Van Bulck <jo.vanbulck@cs.kuleuven.be> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> Acked-by: Kai Huang <kai.huang@intel.com> Link: https://lore.kernel.org/all/20231005153854.25566-12-jo.vanbulck%40cs.kuleuven.be 
The external tests manipulating page permissions expect encl_buffer to be
placed at the start of the test enclave's .data section. As this is not
guaranteed per the C standard, explicitly place encl_buffer in a separate
section that is explicitly placed at the start of the .data segment in the
linker script to avoid the compiler placing it somewhere else in .data.

Signed-off-by: Jo Van Bulck <jo.vanbulck@cs.kuleuven.be>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Acked-by: Kai Huang <kai.huang@intel.com>
Link: https://lore.kernel.org/all/20231005153854.25566-12-jo.vanbulck%40cs.kuleuven.be
selftests/sgx: Ensure test enclave buffer is entirely preserved 2023-12-08T18:05:27+00:00 Jo Van Bulck jo.vanbulck@cs.kuleuven.be 2023-10-05T15:38:51+00:00 a4c39ef4ed43103caef80029cd30427a9ff342d8 Attach the "used" attribute to instruct the compiler to preserve the static encl_buffer, even if it appears it is not entirely referenced in the enclave code, as expected by the external tests manipulating page permissions. Signed-off-by: Jo Van Bulck <jo.vanbulck@cs.kuleuven.be> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> Acked-by: Kai Huang <kai.huang@intel.com> Link: https://lore.kernel.org/all/a2732938-f3db-a0af-3d68-a18060f66e79@cs.kuleuven.be/ Link: https://lore.kernel.org/all/20231005153854.25566-11-jo.vanbulck%40cs.kuleuven.be 
Attach the "used" attribute to instruct the compiler to preserve the static
encl_buffer, even if it appears it is not entirely referenced in the enclave
code, as expected by the external tests manipulating page permissions.

Signed-off-by: Jo Van Bulck <jo.vanbulck@cs.kuleuven.be>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Acked-by: Kai Huang <kai.huang@intel.com>
Link: https://lore.kernel.org/all/a2732938-f3db-a0af-3d68-a18060f66e79@cs.kuleuven.be/
Link: https://lore.kernel.org/all/20231005153854.25566-11-jo.vanbulck%40cs.kuleuven.be
selftests/sgx: Fix linker script asserts 2023-12-08T18:05:27+00:00 Jo Van Bulck jo.vanbulck@cs.kuleuven.be 2023-10-05T15:38:50+00:00 9fd552ee32c6c1e27c125016b87d295bea6faea7 DEFINED only considers symbols, not section names. Hence, replace the check for .got.plt with the _GLOBAL_OFFSET_TABLE_ symbol and remove other (non-essential) asserts. Signed-off-by: Jo Van Bulck <jo.vanbulck@cs.kuleuven.be> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> Link: https://lore.kernel.org/all/20231005153854.25566-10-jo.vanbulck%40cs.kuleuven.be 
DEFINED only considers symbols, not section names. Hence, replace the
check for .got.plt with the _GLOBAL_OFFSET_TABLE_ symbol and remove other
(non-essential) asserts.

Signed-off-by: Jo Van Bulck <jo.vanbulck@cs.kuleuven.be>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Link: https://lore.kernel.org/all/20231005153854.25566-10-jo.vanbulck%40cs.kuleuven.be
selftests/sgx: Handle relocations in test enclave 2023-12-08T18:05:27+00:00 Jo Van Bulck jo.vanbulck@cs.kuleuven.be 2023-10-05T15:38:49+00:00 d06978e8e47a348c0d33462a8c2bf8f46d2b7df5 Static-pie binaries normally include a startup routine to perform any ELF relocations from .rela.dyn. Since the enclave loading process is different and glibc is not included, do the necessary relocation for encl_op_array entries manually at runtime relative to the enclave base to ensure correct function pointers. When keeping encl_op_array as a local variable on the stack, gcc without optimizations generates code that explicitly gets the right function addresses and stores them to create the array on the stack: encl_body: /* snipped */ lea do_encl_op_put_to_buf(%rip), %rax mov %rax, -0x50(%rbp) lea do_encl_op_get_from_buf(%rip), %rax mov %rax,-0x48(%rbp) lea do_encl_op_put_to_addr(%rip), %rax /* snipped */ However, gcc -Os or clang generate more efficient code that initializes encl_op_array by copying a "prepared copy" containing the absolute addresses of the functions (i.e., relative to the image base starting from 0) generated by the compiler/linker: encl_body: /* snipped */ lea prepared_copy(%rip), %rsi lea -0x48(%rsp), %rdi mov $0x10,%ecx rep movsl %ds:(%rsi),%es:(%rdi) /* snipped */ When building the enclave with -static-pie, the compiler/linker includes relocation entries for the function symbols in the "prepared copy": Relocation section '.rela.dyn' at offset 0x4000 contains 12 entries: Offset Info Type Symbol /* snipped; "prepared_copy" starts at 0x6000 */ 000000006000 000000000008 R_X86_64_RELATIVE <do_encl_emodpe> 000000006008 000000000008 R_X86_64_RELATIVE <do_encl_eaccept> 000000006010 000000000008 R_X86_64_RELATIVE <do_encl_op_put_to_buf> 000000006018 000000000008 R_X86_64_RELATIVE <do_encl_op_get_from_buf> 000000006020 000000000008 R_X86_64_RELATIVE <do_encl_op_put_to_addr> 000000006028 000000000008 R_X86_64_RELATIVE <do_encl_op_get_from_addr> 000000006030 000000000008 R_X86_64_RELATIVE <do_encl_op_nop> 000000006038 000000000008 R_X86_64_RELATIVE <do_encl_init_tcs_page> Static-pie binaries normally include a glibc "_dl_relocate_static_pie" routine that will perform these relocations as part of the startup. However, since the enclave loading process is different and glibc is not included, we cannot rely on these relocations to be performed. Without relocations, the code would erroneously jump to the _absolute_ function address loaded from the local copy. Thus, declare "encl_op_array" as global and manually relocate the loaded function-pointer entries relative to the enclave base at runtime. This generates the following code: encl_body: /* snipped */ lea encl_op_array(%rip), %rcx lea __encl_base(%rip), %rax add (%rcx,%rdx,8),%rax jmp *%rax Signed-off-by: Jo Van Bulck <jo.vanbulck@cs.kuleuven.be> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> Acked-by: Kai Huang <kai.huang@intel.com> Link: https://lore.kernel.org/all/150d8ca8-2c66-60d1-f9fc-8e6279824e94@cs.kuleuven.be/ Link: https://lore.kernel.org/all/5c22de5a-4b3b-1f38-9771-409b4ec7f96d@cs.kuleuven.be/#r Link: https://lore.kernel.org/all/20231005153854.25566-9-jo.vanbulck%40cs.kuleuven.be 
Static-pie binaries normally include a startup routine to perform any ELF
relocations from .rela.dyn. Since the enclave loading process is different
and glibc is not included, do the necessary relocation for encl_op_array
entries manually at runtime relative to the enclave base to ensure correct
function pointers.

When keeping encl_op_array as a local variable on the stack, gcc without
optimizations generates code that explicitly gets the right function
addresses and stores them to create the array on the stack:

encl_body:
    /* snipped */
    lea    do_encl_op_put_to_buf(%rip), %rax
    mov    %rax, -0x50(%rbp)
    lea    do_encl_op_get_from_buf(%rip), %rax
    mov    %rax,-0x48(%rbp)
    lea    do_encl_op_put_to_addr(%rip), %rax
    /* snipped */

However, gcc -Os or clang generate more efficient code that initializes
encl_op_array by copying a "prepared copy" containing the absolute
addresses of the functions (i.e., relative to the image base starting from
0) generated by the compiler/linker:

encl_body:
    /* snipped */
    lea    prepared_copy(%rip), %rsi
    lea    -0x48(%rsp), %rdi
    mov    $0x10,%ecx
    rep movsl %ds:(%rsi),%es:(%rdi)
    /* snipped */

When building the enclave with -static-pie, the compiler/linker includes
relocation entries for the function symbols in the "prepared copy":

Relocation section '.rela.dyn' at offset 0x4000 contains 12 entries:
  Offset          Info           Type         Symbol
/* snipped; "prepared_copy" starts at 0x6000 */
000000006000  000000000008 R_X86_64_RELATIVE  <do_encl_emodpe>
000000006008  000000000008 R_X86_64_RELATIVE  <do_encl_eaccept>
000000006010  000000000008 R_X86_64_RELATIVE  <do_encl_op_put_to_buf>
000000006018  000000000008 R_X86_64_RELATIVE  <do_encl_op_get_from_buf>
000000006020  000000000008 R_X86_64_RELATIVE  <do_encl_op_put_to_addr>
000000006028  000000000008 R_X86_64_RELATIVE  <do_encl_op_get_from_addr>
000000006030  000000000008 R_X86_64_RELATIVE  <do_encl_op_nop>
000000006038  000000000008 R_X86_64_RELATIVE  <do_encl_init_tcs_page>

Static-pie binaries normally include a glibc "_dl_relocate_static_pie"
routine that will perform these relocations as part of the startup.
However, since the enclave loading process is different and glibc is not
included, we cannot rely on these relocations to be performed. Without
relocations, the code would erroneously jump to the _absolute_ function
address loaded from the local copy.

Thus, declare "encl_op_array" as global and manually relocate the loaded
function-pointer entries relative to the enclave base at runtime. This
generates the following code:

encl_body:
    /* snipped */
    lea    encl_op_array(%rip), %rcx
    lea    __encl_base(%rip), %rax
    add    (%rcx,%rdx,8),%rax
    jmp    *%rax

Signed-off-by: Jo Van Bulck <jo.vanbulck@cs.kuleuven.be>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Acked-by: Kai Huang <kai.huang@intel.com>
Link: https://lore.kernel.org/all/150d8ca8-2c66-60d1-f9fc-8e6279824e94@cs.kuleuven.be/
Link: https://lore.kernel.org/all/5c22de5a-4b3b-1f38-9771-409b4ec7f96d@cs.kuleuven.be/#r
Link: https://lore.kernel.org/all/20231005153854.25566-9-jo.vanbulck%40cs.kuleuven.be
selftests/sgx: Produce static-pie executable for test enclave 2023-12-08T18:05:27+00:00 Jo Van Bulck jo.vanbulck@cs.kuleuven.be 2023-10-05T15:38:48+00:00 f7884e732841450de36c2b1ed49b91e8e854a7d1 The current combination of -static and -fPIC creates a static executable with position-dependent addresses for global variables. Use -static-pie and -fPIE to create a proper static position independent executable that can be loaded at any address without a dynamic linker. When building the original "lea (encl_stack)(%rbx), %rax" assembly code with -static-pie -fPIE, the linker complains about a relocation it cannot resolve: /usr/local/bin/ld: /tmp/cchIWyfG.o: relocation R_X86_64_32S against `.data' can not be used when making a PIE object; recompile with -fPIE collect2: error: ld returned 1 exit status Thus, since only RIP-relative addressing is legit for local symbols, use "encl_stack(%rip)" and declare an explicit "__encl_base" symbol at the start of the linker script to be able to calculate the stack address relative to the current TCS in the enclave assembly entry code. Signed-off-by: Jo Van Bulck <jo.vanbulck@cs.kuleuven.be> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> Acked-by: Kai Huang <kai.huang@intel.com> Link: https://lore.kernel.org/all/f9c24d89-ed72-7d9e-c650-050d722c6b04@cs.kuleuven.be/ Link: https://lore.kernel.org/all/20231005153854.25566-8-jo.vanbulck%40cs.kuleuven.be 
The current combination of -static and -fPIC creates a static executable
with position-dependent addresses for global variables. Use -static-pie
and -fPIE to create a proper static position independent executable that
can be loaded at any address without a dynamic linker.

When building the original "lea (encl_stack)(%rbx), %rax" assembly code
with -static-pie -fPIE, the linker complains about a relocation it cannot
resolve:

/usr/local/bin/ld: /tmp/cchIWyfG.o: relocation R_X86_64_32S against
`.data' can not be used when making a PIE object; recompile with -fPIE
collect2: error: ld returned 1 exit status

Thus, since only RIP-relative addressing is legit for local symbols, use
"encl_stack(%rip)" and declare an explicit "__encl_base" symbol at the
start of the linker script to be able to calculate the stack address
relative to the current TCS in the enclave assembly entry code.

Signed-off-by: Jo Van Bulck <jo.vanbulck@cs.kuleuven.be>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Acked-by: Kai Huang <kai.huang@intel.com>
Link: https://lore.kernel.org/all/f9c24d89-ed72-7d9e-c650-050d722c6b04@cs.kuleuven.be/
Link: https://lore.kernel.org/all/20231005153854.25566-8-jo.vanbulck%40cs.kuleuven.be
selftests/sgx: Remove redundant enclave base address save/restore 2023-12-08T18:05:27+00:00 Jo Van Bulck jo.vanbulck@cs.kuleuven.be 2023-10-05T15:38:47+00:00 4f812df8f37463767c2a74c2bd77de94acdb2be6 Remove redundant push/pop pair that stores and restores the enclave base address in the test enclave, as it is never used after the pop and can anyway be easily retrieved via the __encl_base symbol. Signed-off-by: Jo Van Bulck <jo.vanbulck@cs.kuleuven.be> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> Acked-by: Kai Huang <kai.huang@intel.com> Link: https://lore.kernel.org/all/20231005153854.25566-7-jo.vanbulck%40cs.kuleuven.be 
Remove redundant push/pop pair that stores and restores the enclave base
address in the test enclave, as it is never used after the pop and can
anyway be easily retrieved via the __encl_base symbol.

Signed-off-by: Jo Van Bulck <jo.vanbulck@cs.kuleuven.be>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Acked-by: Kai Huang <kai.huang@intel.com>
Link: https://lore.kernel.org/all/20231005153854.25566-7-jo.vanbulck%40cs.kuleuven.be
selftests/sgx: Specify freestanding environment for enclave compilation 2023-12-08T18:05:27+00:00 Jo Van Bulck jo.vanbulck@cs.kuleuven.be 2023-10-05T15:38:46+00:00 304b259e63b94c4f825e0648b33b15f8962955c7 Use -ffreestanding to assert the enclave compilation targets a freestanding environment (i.e., without "main" or standard libraries). This fixes clang reporting "undefined reference to `memset'" after erroneously optimizing away the provided memset/memcpy implementations. Still need to instruct the linker from using standard system startup functions, but drop -nostartfiles as it is implied by -nostdlib. Signed-off-by: Jo Van Bulck <jo.vanbulck@cs.kuleuven.be> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> Acked-by: Kai Huang <kai.huang@intel.com> Link: https://lore.kernel.org/all/20231005153854.25566-6-jo.vanbulck%40cs.kuleuven.be 
Use -ffreestanding to assert the enclave compilation targets a
freestanding environment (i.e., without "main" or standard libraries).
This fixes clang reporting "undefined reference to `memset'" after
erroneously optimizing away the provided memset/memcpy implementations.

Still need to instruct the linker from using standard system startup
functions, but drop -nostartfiles as it is implied by -nostdlib.

Signed-off-by: Jo Van Bulck <jo.vanbulck@cs.kuleuven.be>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Acked-by: Kai Huang <kai.huang@intel.com>
Link: https://lore.kernel.org/all/20231005153854.25566-6-jo.vanbulck%40cs.kuleuven.be