pm24.git/arch/powerpc/kernel/vdso, branch cpufreq-rust

powerpc/Makefile: Allow overriding CPP

2024-11-15T00:59:55Z

Unlike all other arches, powerpc doesn't allow the user to override CPP, because it sets it unconditionally in the arch Makefile. This can lead to strange build failures. Instead add the required flags to KBUILD_CPPFLAGS, which are passed to CPP, CC and AS invocations by the generic Makefile logic. Reported-by: Arnd Bergmann Tested-by: Nathan Chancellor Reviewed-by: Nathan Chancellor Closes: https://lore.kernel.org/all/20240607061629.530301-1-arnd@kernel.org Signed-off-by: Arnd Bergmann [mpe: Rebase, write change log, add Arnd's SoB as communicated privately] Signed-off-by: Michael Ellerman Link: https://patch.msgid.link/20241107112646.32401-1-mpe@ellerman.id.au

powerpc/vdso: Drop -mstack-protector-guard flags in 32-bit files with clang

2024-11-04T06:03:10Z

Under certain conditions, the 64-bit '-mstack-protector-guard' flags may end up in the 32-bit vDSO flags, resulting in build failures due to the structure of clang's argument parsing of the stack protector options, which validates the arguments of the stack protector guard flags unconditionally in the frontend, choking on the 64-bit values when targeting 32-bit: clang: error: invalid value 'r13' in 'mstack-protector-guard-reg=', expected one of: r2 clang: error: invalid value 'r13' in 'mstack-protector-guard-reg=', expected one of: r2 make[3]: *** [arch/powerpc/kernel/vdso/Makefile:85: arch/powerpc/kernel/vdso/vgettimeofday-32.o] Error 1 make[3]: *** [arch/powerpc/kernel/vdso/Makefile:87: arch/powerpc/kernel/vdso/vgetrandom-32.o] Error 1 Remove these flags by adding them to the CC32FLAGSREMOVE variable, which already handles situations similar to this. Additionally, reformat and align a comment better for the expanding CONFIG_CC_IS_CLANG block. Cc: stable@vger.kernel.org # v6.1+ Signed-off-by: Nathan Chancellor Signed-off-by: Michael Ellerman Link: https://patch.msgid.link/20241030-powerpc-vdso-drop-stackp-flags-clang-v1-1-d95e7376d29c@kernel.org

powerpc/vdso: Implement __arch_get_vdso_rng_data()

2024-10-16T00:14:40Z

VDSO time functions do not call any other function, so they don't need to save/restore LR. However, retrieving the address of VDSO data page requires using LR hence saving then restoring it, which can be heavy on some CPUs. On the other hand, VDSO functions on powerpc are not standard functions and require a wrapper function to call C VDSO functions. And that wrapper has to save and restore LR in order to call the C VDSO function, so retrieving VDSO data page address in that wrapper doesn't require additional save/restore of LR. For random VDSO functions it is a bit different. Because the function calls __arch_chacha20_blocks_nostack(), it saves and restores LR. Retrieving VDSO data page address can then be done there without additional save/restore of LR. So lets implement __arch_get_vdso_rng_data() and simplify the wrapper. It starts paving the way for the day powerpc will implement a more standard ABI for VDSO functions. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://patch.msgid.link/a1a9bd0df508f1b5c04684b7366940577dfc6262.1727858295.git.christophe.leroy@csgroup.eu

powerpc/vdso: Add a page for non-time data

2024-10-16T00:08:20Z

The page containing VDSO time data is swapped with the one containing TIME namespace data when a process uses a non-root time namespace. For other data like powerpc specific data and RNG data, it means tracking whether time namespace is the root one or not to know which page to use. Simplify the logic behind by moving time data out of first data page so that the first data page which contains everything else always remains the first page. Time data is in the second or third page depending on selected time namespace. While we are playing with get_datapage macro, directly take into account the data offset inside the macro instead of adding that offset afterwards. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://patch.msgid.link/0557d3ec898c1d0ea2fc59fa8757618e524c5d94.1727858295.git.christophe.leroy@csgroup.eu

powerpc/vdso: allow r30 in vDSO code generation of getrandom

2024-09-30T09:19:43Z

For gettimeofday, -ffixed-r30 was passed to work around a bug in Go code, where the vDSO trampoline forgot to save and restore this register across function calls. But Go requires a different trampoline for every call, and there's no reason that new Go code needs to be broken and add more bugs. So remove -ffixed-r30 for getrandom. Fixes: 8072b39c3a75 ("powerpc/vdso: Wire up getrandom() vDSO implementation on VDSO64") Signed-off-by: Jason A. Donenfeld Signed-off-by: Michael Ellerman Link: https://msgid.link/20240925175021.1526936-2-Jason@zx2c4.com

Merge tag 'powerpc-6.12-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

2024-09-19T06:03:00Z

Pull powerpc updates from Michael Ellerman: - Reduce alignment constraints on STRICT_KERNEL_RWX and speed-up TLB misses on 8xx and 603 - Replace kretprobe code with rethook and enable fprobe - Remove the "fast endian switch" syscall - Handle DLPAR device tree updates in kernel, allowing the deprecation of the binary /proc/powerpc/ofdt interface Thanks to Abhishek Dubey, Alex Shi, Benjamin Gray, Christophe Leroy, Gaosheng Cui, Gautam Menghani, Geert Uytterhoeven, Haren Myneni, Hari Bathini, Huang Xiaojia, Jinjie Ruan, Madhavan Srinivasan, Miguel Ojeda, Mina Almasry, Narayana Murty N, Naveen Rao, Rob Herring (Arm), Scott Cheloha, Segher Boessenkool, Stephen Rothwell, Thomas Zimmermann, Uwe Kleine-König, Vaibhav Jain, and Zhang Zekun. * tag 'powerpc-6.12-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (59 commits) powerpc/atomic: Use YZ constraints for DS-form instructions MAINTAINERS: powerpc: Add Maddy powerpc: Switch back to struct platform_driver::remove() powerpc/pseries/eeh: Fix pseries_eeh_err_inject selftests/powerpc: Allow building without static libc macintosh/via-pmu: register_pmu_pm_ops() can be __init powerpc: Stop using no_llseek powerpc/64s: Remove the "fast endian switch" syscall powerpc/mm/64s: Restrict THP to Radix or HPT w/64K pages powerpc/mm/64s: Move THP reqs into a separate symbol powerpc/64s: Make mmu_hash_ops __ro_after_init powerpc: Replace kretprobe code with rethook on powerpc powerpc: pseries: Constify struct kobj_type powerpc: powernv: Constify struct kobj_type powerpc: Constify struct kobj_type powerpc/pseries/dlpar: Add device tree nodes for DLPAR IO add powerpc/pseries/dlpar: Remove device tree node for DLPAR IO remove powerpc/pseries: Use correct data types from pseries_hp_errorlog struct powerpc/vdso: Inconditionally use CFUNC macro powerpc/32: Implement validation of emergency stack ...

Merge tag 'random-6.12-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random

2024-09-18T13:26:31Z

Pull random number generator updates from Jason Donenfeld: "Originally I'd planned on sending each of the vDSO getrandom() architecture ports to their respective arch trees. But as we started to work on this, we found lots of interesting issues in the shared code and infrastructure, the fixes for which the various archs needed to base their work. So in the end, this turned into a nice collaborative effort fixing up issues and porting to 5 new architectures -- arm64, powerpc64, powerpc32, s390x, and loongarch64 -- with everybody pitching in and commenting on each other's code. It was a fun development cycle. This contains: - Numerous fixups to the vDSO selftest infrastructure, getting it running successfully on more platforms, and fixing bugs in it. - Additions to the vDSO getrandom & chacha selftests. Basically every time manual review unearthed a bug in a revision of an arch patch, or an ambiguity, the tests were augmented. By the time the last arch was submitted for review, s390x, v1 of the series was essentially fine right out of the gate. - Fixes to the the generic C implementation of vDSO getrandom, to build and run successfully on all archs, decoupling it from assumptions we had (unintentionally) made on x86_64 that didn't carry through to the other architectures. - Port of vDSO getrandom to LoongArch64, from Xi Ruoyao and acked by Huacai Chen. - Port of vDSO getrandom to ARM64, from Adhemerval Zanella and acked by Will Deacon. - Port of vDSO getrandom to PowerPC, in both 32-bit and 64-bit varieties, from Christophe Leroy and acked by Michael Ellerman. - Port of vDSO getrandom to S390X from Heiko Carstens, the arch maintainer. While it'd be natural for there to be things to fix up over the course of the development cycle, these patches got a decent amount of review from a fairly diverse crew of folks on the mailing lists, and, for the most part, they've been cooking in linux-next, which has been helpful for ironing out build issues. In terms of architectures, I think that mostly takes care of the important 64-bit archs with hardware still being produced and running production loads in settings where vDSO getrandom is likely to help. Arguably there's still RISC-V left, and we'll see for 6.13 whether they find it useful and submit a port" * tag 'random-6.12-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random: (47 commits) selftests: vDSO: check cpu caps before running chacha test s390/vdso: Wire up getrandom() vdso implementation s390/vdso: Move vdso symbol handling to separate header file s390/vdso: Allow alternatives in vdso code s390/module: Provide find_section() helper s390/facility: Let test_facility() generate static branch if possible s390/alternatives: Remove ALT_FACILITY_EARLY s390/facility: Disable compile time optimization for decompressor code selftests: vDSO: fix vdso_config for s390 selftests: vDSO: fix ELF hash table entry size for s390x powerpc/vdso: Wire up getrandom() vDSO implementation on VDSO64 powerpc/vdso: Wire up getrandom() vDSO implementation on VDSO32 powerpc/vdso: Refactor CFLAGS for CVDSO build powerpc/vdso32: Add crtsavres mm: Define VM_DROPPABLE for powerpc/32 powerpc/vdso: Fix VDSO data access when running in a non-root time namespace selftests: vDSO: don't include generated headers for chacha test arm64: vDSO: Wire up getrandom() vDSO implementation arm64: alternative: make alternative_has_cap_likely() VDSO compatible selftests: vDSO: also test counter in vdso_test_chacha ...

powerpc/vdso: Wire up getrandom() vDSO implementation on VDSO64

2024-09-13T15:28:36Z

Extend getrandom() vDSO implementation to VDSO64. Tested on QEMU on both ppc64_defconfig and ppc64le_defconfig. Results from a Power9 (PowerNV): ~ # ./vdso_test_getrandom bench-single vdso: 25000000 times in 0.787943615 seconds libc: 25000000 times in 14.101887252 seconds syscall: 25000000 times in 14.047475082 seconds Signed-off-by: Christophe Leroy Tested-by: Madhavan Srinivasan Acked-by: Michael Ellerman Signed-off-by: Jason A. Donenfeld

powerpc/vdso: Wire up getrandom() vDSO implementation on VDSO32

2024-09-13T15:28:36Z

To be consistent with other VDSO functions, the function is called __kernel_getrandom() __arch_chacha20_blocks_nostack() fonction is implemented basically with 32 bits operations. It performs 4 QUARTERROUND operations in parallele. There are enough registers to avoid using the stack: On input: r3: output bytes r4: 32-byte key input r5: 8-byte counter input/output r6: number of 64-byte blocks to write to output During operation: stack: pointer to counter (r5) and non-volatile registers (r14-131) r0: counter of blocks (initialised with r6) r4: Value '4' after key has been read, used for indexing r5-r12: key r14-r15: block counter r16-r31: chacha state At the end: r0, r6-r12: Zeroised r5, r14-r31: Restored Performance on powerpc 885 (using kernel selftest): ~# ./vdso_test_getrandom bench-single vdso: 25000000 times in 62.938002291 seconds libc: 25000000 times in 535.581916866 seconds syscall: 25000000 times in 531.525042806 seconds Performance on powerpc 8321 (using kernel selftest): ~# ./vdso_test_getrandom bench-single vdso: 25000000 times in 16.899318858 seconds libc: 25000000 times in 131.050596522 seconds syscall: 25000000 times in 129.794790389 seconds This first patch adds support for VDSO32. As selftests cannot easily be generated only for VDSO32, and because the following patch brings support for VDSO64 anyway, this patch opts out all code in __arch_chacha20_blocks_nostack() so that vdso_test_chacha will not fail to compile and will not crash on PPC64/PPC64LE, allthough the selftest itself will fail. Signed-off-by: Christophe Leroy Acked-by: Michael Ellerman Signed-off-by: Jason A. Donenfeld

powerpc/vdso: Refactor CFLAGS for CVDSO build

2024-09-13T15:28:36Z

In order to avoid two much duplication when we add new VDSO functionnalities in C like getrandom, refactor common CFLAGS. Signed-off-by: Christophe Leroy Acked-by: Michael Ellerman Signed-off-by: Jason A. Donenfeld