kernel/linux.git/tools/testing/selftests/rseq, branch v5.4.206

selftests/rseq: Change type of rseq_offset to ptrdiff_t

2022-07-07T15:36:52+00:00

commit 889c5d60fbcf332c8b6ab7054d45f2768914a375 upstream. Just before the 2.35 release of glibc, the __rseq_offset userspace ABI was changed from int to ptrdiff_t. Adapt to this change in the kernel selftests. Signed-off-by: Mathieu Desnoyers Signed-off-by: Peter Zijlstra (Intel) Link: https://sourceware.org/pipermail/libc-alpha/2022-February/136024.html Signed-off-by: Greg Kroah-Hartman

selftests/rseq: x86-32: use %gs segment selector for accessing rseq thread area

2022-07-07T15:36:52+00:00

commit 127b6429d235ab7c358223bbfd8a8b8d8cc799b6 upstream. Rather than use rseq_get_abi() and pass its result through a register to the inline assembler, directly access the per-thread rseq area through a memory reference combining the %gs segment selector, the constant offset of the field in struct rseq, and the rseq_offset value (in a register). Signed-off-by: Mathieu Desnoyers Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20220124171253.22072-16-mathieu.desnoyers@efficios.com Signed-off-by: Greg Kroah-Hartman

selftests/rseq: x86-64: use %fs segment selector for accessing rseq thread area

2022-07-07T15:36:52+00:00

commit 4e15bb766b6c6e963a4d33629034d0ec3b7637df upstream. Rather than use rseq_get_abi() and pass its result through a register to the inline assembler, directly access the per-thread rseq area through a memory reference combining the %fs segment selector, the constant offset of the field in struct rseq, and the rseq_offset value (in a register). Signed-off-by: Mathieu Desnoyers Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20220124171253.22072-15-mathieu.desnoyers@efficios.com Signed-off-by: Greg Kroah-Hartman

selftests/rseq: Fix: work-around asm goto compiler bugs

2022-07-07T15:36:52+00:00

commit b53823fb2ef854222853be164f3b1e815f315144 upstream. gcc and clang each have their own compiler bugs with respect to asm goto. Implement a work-around for compiler versions known to have those bugs. gcc prior to 4.8.2 miscompiles asm goto. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670 gcc prior to 8.1.0 miscompiles asm goto at O1. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103908 clang prior to version 13.0.1 miscompiles asm goto at O2. https://github.com/llvm/llvm-project/issues/52735 Work around these issues by adding a volatile inline asm with memory clobber in the fallthrough after the asm goto and at each label target. Emit this for all compilers in case other similar issues are found in the future. Signed-off-by: Mathieu Desnoyers Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20220124171253.22072-14-mathieu.desnoyers@efficios.com Signed-off-by: Greg Kroah-Hartman

selftests/rseq: Remove arm/mips asm goto compiler work-around

2022-07-07T15:36:52+00:00

commit 94c5cf2a0e193afffef8de48ddc42de6df7cac93 upstream. The arm and mips work-around for asm goto size guess issues are not properly documented, and lack reference to specific compiler versions, upstream compiler bug tracker entry, and reproducer. I can only find a loosely documented patch in my original LKML rseq post refering to gcc < 7 on ARM, but it does not appear to be sufficient to track the exact issue. Also, I am not sure MIPS really has the same limitation. Therefore, remove the work-around until we can properly document this. Signed-off-by: Mathieu Desnoyers Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/lkml/20171121141900.18471-17-mathieu.desnoyers@efficios.com/ Signed-off-by: Greg Kroah-Hartman

selftests/rseq: Fix warnings about #if checks of undefined tokens

2022-07-07T15:36:52+00:00

commit d7ed99ade3e62b755584eea07b4e499e79240527 upstream. Signed-off-by: Mathieu Desnoyers Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20220124171253.22072-12-mathieu.desnoyers@efficios.com Signed-off-by: Greg Kroah-Hartman

selftests/rseq: Fix ppc32 offsets by using long rather than off_t

2022-07-07T15:36:52+00:00

commit 26dc8a6d8e11552f3b797b5aafe01071ca32d692 upstream. The semantic of off_t is for file offsets. We mean to use it as an offset from a pointer. We really expect it to fit in a single register, and not use a 64-bit type on 32-bit architectures. Fix runtime issues on ppc32 where the offset is always 0 due to inconsistency between the argument type (off_t -> 64-bit) and type expected by the inline assembler (32-bit). Signed-off-by: Mathieu Desnoyers Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20220124171253.22072-11-mathieu.desnoyers@efficios.com Signed-off-by: Greg Kroah-Hartman

selftests/rseq: Fix ppc32 missing instruction selection "u" and "x" for load/store

2022-07-07T15:36:52+00:00

commit de6b52a21420a18dc8a36438d581efd1313d5fe3 upstream. Building the rseq basic test with gcc version 5.4.0 20160609 (Ubuntu 5.4.0-6ubuntu1~16.04.12) Target: powerpc-linux-gnu leads to these errors: /tmp/ccieEWxU.s: Assembler messages: /tmp/ccieEWxU.s:118: Error: syntax error; found `,', expected `(' /tmp/ccieEWxU.s:118: Error: junk at end of line: `,8' /tmp/ccieEWxU.s:121: Error: syntax error; found `,', expected `(' /tmp/ccieEWxU.s:121: Error: junk at end of line: `,8' /tmp/ccieEWxU.s:626: Error: syntax error; found `,', expected `(' /tmp/ccieEWxU.s:626: Error: junk at end of line: `,8' /tmp/ccieEWxU.s:629: Error: syntax error; found `,', expected `(' /tmp/ccieEWxU.s:629: Error: junk at end of line: `,8' /tmp/ccieEWxU.s:735: Error: syntax error; found `,', expected `(' /tmp/ccieEWxU.s:735: Error: junk at end of line: `,8' /tmp/ccieEWxU.s:738: Error: syntax error; found `,', expected `(' /tmp/ccieEWxU.s:738: Error: junk at end of line: `,8' /tmp/ccieEWxU.s:741: Error: syntax error; found `,', expected `(' /tmp/ccieEWxU.s:741: Error: junk at end of line: `,8' Makefile:581: recipe for target 'basic_percpu_ops_test.o' failed Based on discussion with Linux powerpc maintainers and review of the use of the "m" operand in powerpc kernel code, add the missing %Un%Xn (where n is operand number) to the lwz, stw, ld, and std instructions when used with "m" operands. Using "WORD" to mean either a 32-bit or 64-bit type depending on the architecture is misleading. The term "WORD" really means a 32-bit type in both 32-bit and 64-bit powerpc assembler. The intent here is to wrap load/store to intptr_t into common macros for both 32-bit and 64-bit. Rename the macros with a RSEQ_ prefix, and use the terms "INT" for always 32-bit type, and "LONG" for architecture bitness-sized type. Signed-off-by: Mathieu Desnoyers Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20220124171253.22072-10-mathieu.desnoyers@efficios.com Signed-off-by: Greg Kroah-Hartman

selftests/rseq: Fix ppc32: wrong rseq_cs 32-bit field pointer on big endian

2022-07-07T15:36:52+00:00

commit 24d1136a29da5953de5c0cbc6c83eb62a1e0bf14 upstream. ppc32 incorrectly uses padding as rseq_cs pointer field. Fix this by using the rseq_cs.arch.ptr field. Use this field across all architectures. Signed-off-by: Mathieu Desnoyers Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20220124171253.22072-9-mathieu.desnoyers@efficios.com Signed-off-by: Greg Kroah-Hartman

selftests/rseq: Uplift rseq selftests for compatibility with glibc-2.35

2022-07-07T15:36:51+00:00

commit 233e667e1ae3e348686bd9dd0172e62a09d852e1 upstream. glibc-2.35 (upcoming release date 2022-02-01) exposes the rseq per-thread data in the TCB, accessible at an offset from the thread pointer, rather than through an actual Thread-Local Storage (TLS) variable, as the Linux kernel selftests initially expected. The __rseq_abi TLS and glibc-2.35's ABI for per-thread data cannot actively coexist in a process, because the kernel supports only a single rseq registration per thread. Here is the scheme introduced to ensure selftests can work both with an older glibc and with glibc-2.35+: - librseq exposes its own "rseq_offset, rseq_size, rseq_flags" ABI. - librseq queries for glibc rseq ABI (__rseq_offset, __rseq_size, __rseq_flags) using dlsym() in a librseq library constructor. If those are found, copy their values into rseq_offset, rseq_size, and rseq_flags. - Else, if those glibc symbols are not found, handle rseq registration from librseq and use its own IE-model TLS to implement the rseq ABI per-thread storage. Signed-off-by: Mathieu Desnoyers Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20220124171253.22072-8-mathieu.desnoyers@efficios.com Signed-off-by: Greg Kroah-Hartman