kernel.git/arch/powerpc/include/asm/uaccess.h, branch linux-6.1.y

powerpc/uaccess: Move barrier_nospec() out of allow_read_{from/write}_user()

2026-03-04T12:19:33Z

[ Upstream commit 5fbc09eb0b4f4b1a4b33abebacbeee0d29f195e9 ] Commit 74e19ef0ff80 ("uaccess: Add speculation barrier to copy_from_user()") added a redundant barrier_nospec() in copy_from_user(), because powerpc is already calling barrier_nospec() in allow_read_from_user() and allow_read_write_user(). But on other architectures that call to barrier_nospec() was missing. So change powerpc instead of reverting the above commit and having to fix other architectures one by one. This is now possible because barrier_nospec() has also been added in copy_from_user_iter(). Move barrier_nospec() out of allow_read_from_user() and allow_read_write_user(). This will also allow reuse of those functions when implementing masked user access which doesn't require barrier_nospec(). Don't add it back in raw_copy_from_user() as it is already called by copy_from_user() and copy_from_user_iter(). Fixes: 74e19ef0ff80 ("uaccess: Add speculation barrier to copy_from_user()") Signed-off-by: Christophe Leroy Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/f29612105c5fcbc8ceb7303808ddc1a781f0f6b5.1766574657.git.chleroy@kernel.org Signed-off-by: Sasha Levin

powerpc/atomic: Use YZ constraints for DS-form instructions

2024-10-17T13:21:24Z

[ Upstream commit 39190ac7cff1fd15135fa8e658030d9646fdb5f2 ] The 'ld' and 'std' instructions require a 4-byte aligned displacement because they are DS-form instructions. But the "m" asm constraint doesn't enforce that. That can lead to build errors if the compiler chooses a non-aligned displacement, as seen with GCC 14: /tmp/ccuSzwiR.s: Assembler messages: /tmp/ccuSzwiR.s:2579: Error: operand out of domain (39 is not a multiple of 4) make[5]: *** [scripts/Makefile.build:229: net/core/page_pool.o] Error 1 Dumping the generated assembler shows: ld 8,39(8) # MEM[(const struct atomic64_t *)_29].counter, t Use the YZ constraints to tell the compiler either to generate a DS-form displacement, or use an X-form instruction, either of which prevents the build error. See commit 2d43cc701b96 ("powerpc/uaccess: Fix build errors seen with GCC 13/14") for more details on the constraint letters. Fixes: 9f0cbea0d8cc ("[POWERPC] Implement atomic{, 64}_{read, write}() without volatile") Cc: stable@vger.kernel.org # v2.6.24+ Reported-by: Stephen Rothwell Closes: https://lore.kernel.org/all/20240913125302.0a06b4c7@canb.auug.org.au Tested-by: Mina Almasry Reviewed-by: Segher Boessenkool Signed-off-by: Michael Ellerman Link: https://msgid.link/20240916120510.2017749-1-mpe@ellerman.id.au Signed-off-by: Sasha Levin

powerpc/64: Add support to build with prefixed instructions

2024-10-17T13:21:24Z

[ Upstream commit dc5dac748af9087e9240bd2ae6ae7db48d5360ae ] Add an option to build kernel and module with prefixed instructions if the CPU and toolchain support it. This is not related to kernel support for userspace execution of prefixed instructions. Building with prefixed instructions breaks some extended inline asm memory addressing, for example it will provide immediates that exceed the range of simple load/store displacement. Whether this is a toolchain or a kernel asm problem remains to be seen. For now, these are replaced with simpler and less efficient direct register addressing when compiling with prefixed. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://msgid.link/20230408021752.862660-4-npiggin@gmail.com Stable-dep-of: 39190ac7cff1 ("powerpc/atomic: Use YZ constraints for DS-form instructions") Signed-off-by: Sasha Levin

powerpc/uaccess: Fix build errors seen with GCC 13/14

2024-06-21T12:35:45Z

commit 2d43cc701b96f910f50915ac4c2a0cae5deb734c upstream. Building ppc64le_defconfig with GCC 14 fails with assembler errors: CC fs/readdir.o /tmp/ccdQn0mD.s: Assembler messages: /tmp/ccdQn0mD.s:212: Error: operand out of domain (18 is not a multiple of 4) /tmp/ccdQn0mD.s:226: Error: operand out of domain (18 is not a multiple of 4) ... [6 lines] /tmp/ccdQn0mD.s:1699: Error: operand out of domain (18 is not a multiple of 4) A snippet of the asm shows: # ../fs/readdir.c:210: unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end); ld 9,0(29) # MEM[(u64 *)name_38(D) + _88 * 1], MEM[(u64 *)name_38(D) + _88 * 1] # 210 "../fs/readdir.c" 1 1: std 9,18(8) # put_user # *__pus_addr_52, MEM[(u64 *)name_38(D) + _88 * 1] The 'std' instruction requires a 4-byte aligned displacement because it is a DS-form instruction, and as the assembler says, 18 is not a multiple of 4. A similar error is seen with GCC 13 and CONFIG_UBSAN_SIGNED_WRAP=y. The fix is to change the constraint on the memory operand to put_user(), from "m" which is a general memory reference to "YZ". The "Z" constraint is documented in the GCC manual PowerPC machine constraints, and specifies a "memory operand accessed with indexed or indirect addressing". "Y" is not documented in the manual but specifies a "memory operand for a DS-form instruction". Using both allows the compiler to generate a DS-form "std" or X-form "stdx" as appropriate. The change has to be conditional on CONFIG_PPC_KERNEL_PREFIXED because the "Y" constraint does not guarantee 4-byte alignment when prefixed instructions are enabled. Unfortunately clang doesn't support the "Y" constraint so that has to be behind an ifdef. Although the build error is only seen with GCC 13/14, that appears to just be luck. The constraint has been incorrect since it was first added. Fixes: c20beffeec3c ("powerpc/uaccess: Use flexible addressing with __put_user()/__get_user()") Cc: stable@vger.kernel.org # v5.10+ Suggested-by: Kewen Lin Signed-off-by: Michael Ellerman Link: https://msgid.link/20240529123029.146953-1-mpe@ellerman.id.au Signed-off-by: Greg Kroah-Hartman

work around gcc bugs with 'asm goto' with outputs

2024-02-23T08:12:28Z

commit 68fb3ca0e408e00db1c3f8fccdfa19e274c033be upstream. We've had issues with gcc and 'asm goto' before, and we created a 'asm_volatile_goto()' macro for that in the past: see commits 3f0116c3238a ("compiler/gcc4: Add quirk for 'asm goto' miscompilation bug") and a9f180345f53 ("compiler/gcc4: Make quirk for asm_volatile_goto() unconditional"). Then, much later, we ended up removing the workaround in commit 43c249ea0b1e ("compiler-gcc.h: remove ancient workaround for gcc PR 58670") because we no longer supported building the kernel with the affected gcc versions, but we left the macro uses around. Now, Sean Christopherson reports a new version of a very similar problem, which is fixed by re-applying that ancient workaround. But the problem in question is limited to only the 'asm goto with outputs' cases, so instead of re-introducing the old workaround as-is, let's rename and limit the workaround to just that much less common case. It looks like there are at least two separate issues that all hit in this area: (a) some versions of gcc don't mark the asm goto as 'volatile' when it has outputs: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98619 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110420 which is easy to work around by just adding the 'volatile' by hand. (b) Internal compiler errors: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110422 which are worked around by adding the extra empty 'asm' as a barrier, as in the original workaround. but the problem Sean sees may be a third thing since it involves bad code generation (not an ICE) even with the manually added 'volatile'. The same old workaround works for this case, even if this feels a bit like voodoo programming and may only be hiding the issue. Reported-and-tested-by: Sean Christopherson Link: https://lore.kernel.org/all/20240208220604.140859-1-seanjc@google.com/ Cc: Nick Desaulniers Cc: Uros Bizjak Cc: Jakub Jelinek Cc: Andrew Pinski Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

Merge tag 'powerpc-6.0-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

2022-08-06T23:38:17Z

Pull powerpc updates from Michael Ellerman: - Add support for syscall stack randomization - Add support for atomic operations to the 32 & 64-bit BPF JIT - Full support for KASAN on 64-bit Book3E - Add a watchdog driver for the new PowerVM hypervisor watchdog - Add a number of new selftests for the Power10 PMU support - Add a driver for the PowerVM Platform KeyStore - Increase the NMI watchdog timeout during live partition migration, to avoid timeouts due to increased memory access latency - Add support for using the 'linux,pci-domain' device tree property for PCI domain assignment - Many other small features and fixes Thanks to Alexey Kardashevskiy, Andy Shevchenko, Arnd Bergmann, Athira Rajeev, Bagas Sanjaya, Christophe Leroy, Erhard Furtner, Fabiano Rosas, Greg Kroah-Hartman, Greg Kurz, Haowen Bai, Hari Bathini, Jason A. Donenfeld, Jason Wang, Jiang Jian, Joel Stanley, Juerg Haefliger, Kajol Jain, Kees Cook, Laurent Dufour, Madhavan Srinivasan, Masahiro Yamada, Maxime Bizon, Miaoqian Lin, Murilo Opsfelder Araújo, Nathan Lynch, Naveen N. Rao, Nayna Jain, Nicholas Piggin, Ning Qiang, Pali Rohár, Petr Mladek, Rashmica Gupta, Sachin Sant, Scott Cheloha, Segher Boessenkool, Stephen Rothwell, Uwe Kleine-König, Wolfram Sang, Xiu Jianfeng, and Zhouyi Zhou. * tag 'powerpc-6.0-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (191 commits) powerpc/64e: Fix kexec build error EDAC/ppc_4xx: Include required of_irq header directly powerpc/pci: Fix PHB numbering when using opal-phbid powerpc/64: Init jump labels before parse_early_param() selftests/powerpc: Avoid GCC 12 uninitialised variable warning powerpc/cell/axon_msi: Fix refcount leak in setup_msi_msg_address powerpc/xive: Fix refcount leak in xive_get_max_prio powerpc/spufs: Fix refcount leak in spufs_init_isolated_loader powerpc/perf: Include caps feature for power10 DD1 version powerpc: add support for syscall stack randomization powerpc: Move system_call_exception() to syscall.c powerpc/powernv: rename remaining rng powernv_ functions to pnv_ powerpc/powernv/kvm: Use darn for H_RANDOM on Power9 powerpc/powernv: Avoid crashing if rng is NULL selftests/powerpc: Fix matrix multiply assist test powerpc/signal: Update comment for clarity powerpc: make facility_unavailable_exception 64s powerpc/platforms/83xx/suspend: Remove write-only global variable powerpc/platforms/83xx/suspend: Prevent unloading the driver powerpc/platforms/83xx/suspend: Reorder to get rid of a forward declaration ...

powerpc: Don't include asm/ppc_asm.h in other headers

2022-06-29T06:45:13Z

asm/ppc_asm.h is not needed in any of the header it is included. It is only needed by irq.c. Include it there and remove it from other headers. word-at-a-time.h only need ex_table.h, so include it instead. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/e2d7b96547037f852c7ed164e4f79e8918c2607a.1651828453.git.christophe.leroy@csgroup.eu

No need of likely/unlikely on calls of check_copy_size()

2022-06-07T20:18:08Z

it's inline and unlikely() inside of it (including the implicit one in WARN_ON_ONCE()) suffice to convince the compiler that getting false from check_copy_size() is unlikely. Spotted-by: Jens Axboe Reviewed-by: Christoph Hellwig Reviewed-by: Christian Brauner (Microsoft) Signed-off-by: Al Viro

Merge tag 'powerpc-5.18-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

2022-03-25T16:39:36Z

Pull powerpc updates from Michael Ellerman: "Livepatch support for 32-bit is probably the standout new feature, otherwise mostly just lots of bits and pieces all over the board. There's a series of commits cleaning up function descriptor handling, which touches a few other arches as well as LKDTM. It has acks from Arnd, Kees and Helge. Summary: - Enforce kernel RO, and implement STRICT_MODULE_RWX for 603. - Add support for livepatch to 32-bit. - Implement CONFIG_DYNAMIC_FTRACE_WITH_ARGS. - Merge vdso64 and vdso32 into a single directory. - Fix build errors with newer binutils. - Add support for UADDR64 relocations, which are emitted by some toolchains. This allows powerpc to build with the latest lld. - Fix (another) potential userspace r13 corruption in transactional memory handling. - Cleanups of function descriptor handling & related fixes to LKDTM. Thanks to Abdul Haleem, Alexey Kardashevskiy, Anders Roxell, Aneesh Kumar K.V, Anton Blanchard, Arnd Bergmann, Athira Rajeev, Bhaskar Chowdhury, Cédric Le Goater, Chen Jingwen, Christophe JAILLET, Christophe Leroy, Corentin Labbe, Daniel Axtens, Daniel Henrique Barboza, David Dai, Fabiano Rosas, Ganesh Goudar, Guo Zhengkui, Hangyu Hua, Haren Myneni, Hari Bathini, Igor Zhbanov, Jakob Koschel, Jason Wang, Jeremy Kerr, Joachim Wiberg, Jordan Niethe, Julia Lawall, Kajol Jain, Kees Cook, Laurent Dufour, Madhavan Srinivasan, Mamatha Inamdar, Maxime Bizon, Maxim Kiselev, Maxim Kochetkov, Michal Suchanek, Nageswara R Sastry, Nathan Lynch, Naveen N. Rao, Nicholas Piggin, Nour-eddine Taleb, Paul Menzel, Ping Fang, Pratik R. Sampat, Randy Dunlap, Ritesh Harjani, Rohan McLure, Russell Currey, Sachin Sant, Segher Boessenkool, Shivaprasad G Bhat, Sourabh Jain, Thierry Reding, Tobias Waldekranz, Tyrel Datwyler, Vaibhav Jain, Vladimir Oltean, Wedson Almeida Filho, and YueHaibing" * tag 'powerpc-5.18-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (179 commits) powerpc/pseries: Fix use after free in remove_phb_dynamic() powerpc/time: improve decrementer clockevent processing powerpc/time: Fix KVM host re-arming a timer beyond decrementer range powerpc/tm: Fix more userspace r13 corruption powerpc/xive: fix return value of __setup handler powerpc/64: Add UADDR64 relocation support powerpc: 8xx: fix a return value error in mpc8xx_pic_init powerpc/ps3: remove unneeded semicolons powerpc/64: Force inlining of prevent_user_access() and set_kuap() powerpc/bitops: Force inlining of fls() powerpc: declare unmodified attribute_group usages const powerpc/spufs: Fix build warning when CONFIG_PROC_FS=n powerpc/secvar: fix refcount leak in format_show() powerpc/64e: Tie PPC_BOOK3E_64 to PPC_FSL_BOOK3E powerpc: Move C prototypes out of asm-prototypes.h powerpc/kexec: Declare kexec_paca static powerpc/smp: Declare current_set static powerpc: Cleanup asm-prototypes.c powerpc/ftrace: Use STK_GOT in ftrace_mprofile.S powerpc/ftrace: Regroup PPC64 specific operations in ftrace_mprofile.S ...

powerpc: Fix build errors with newer binutils

2022-03-01T12:51:08Z

Building tinyconfig with gcc (Debian 11.2.0-16) and assembler (Debian 2.37.90.20220207) the following build error shows up: {standard input}: Assembler messages: {standard input}:1190: Error: unrecognized opcode: `stbcix' {standard input}:1433: Error: unrecognized opcode: `lwzcix' {standard input}:1453: Error: unrecognized opcode: `stbcix' {standard input}:1460: Error: unrecognized opcode: `stwcix' {standard input}:1596: Error: unrecognized opcode: `stbcix' ... Rework to add assembler directives [1] around the instruction. Going through them one by one shows that the changes should be safe. Like __get_user_atomic_128_aligned() is only called in p9_hmi_special_emu(), which according to the name is specific to power9. And __raw_rm_read*() are only called in things that are powernv or book3s_hv specific. [1] https://sourceware.org/binutils/docs/as/PowerPC_002dPseudo.html#PowerPC_002dPseudo Cc: stable@vger.kernel.org Co-developed-by: Arnd Bergmann Signed-off-by: Arnd Bergmann Signed-off-by: Anders Roxell Reviewed-by: Segher Boessenkool [mpe: Make commit subject more descriptive] Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220224162215.3406642-2-anders.roxell@linaro.org