kernel/arch/powerpc/include/asm/ppc_asm.h, branch linux-rolling-stable

powerpc: Replace ASSEMBLY with ASSEMBLER in non-uapi headers

2025-09-01T07:53:29Z

While the GCC and Clang compilers already define __ASSEMBLER__ automatically when compiling assembler code, __ASSEMBLY__ is a macro that only gets defined by the Makefiles in the kernel. This is bad since macros starting with two underscores are names that are reserved by the C language. It can also be very confusing for the developers when switching between userspace and kernelspace coding, or when dealing with uapi headers that rather should use __ASSEMBLER__ instead. So let's standardize now on the __ASSEMBLER__ macro that is provided by the compilers. This is almost a completely mechanical patch (done with a simple "sed -i" statement), apart from tweaking two comments manually in arch/powerpc/include/asm/bug.h and arch/powerpc/include/asm/kasan.h (which did not have proper underscores at the end) and fixing a checkpatch error about spaces in arch/powerpc/include/asm/spu_csa.h. Signed-off-by: Thomas Huth Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/20250801082007.32904-3-thuth@redhat.com

powerpc/vdso: Fix build of VDSO32 with pcrel

2025-06-13T07:00:15Z

Building vdso32 on power10 with pcrel leads to following errors: VDSO32A arch/powerpc/kernel/vdso/gettimeofday-32.o arch/powerpc/kernel/vdso/gettimeofday.S: Assembler messages: arch/powerpc/kernel/vdso/gettimeofday.S:40: Error: syntax error; found `@', expected `,' arch/powerpc/kernel/vdso/gettimeofday.S:71: Info: macro invoked from here arch/powerpc/kernel/vdso/gettimeofday.S:40: Error: junk at end of line: `@notoc' arch/powerpc/kernel/vdso/gettimeofday.S:71: Info: macro invoked from here ... make[2]: *** [arch/powerpc/kernel/vdso/Makefile:85: arch/powerpc/kernel/vdso/gettimeofday-32.o] Error 1 make[1]: *** [arch/powerpc/Makefile:388: vdso_prepare] Error 2 Once the above is fixed, the following happens: VDSO32C arch/powerpc/kernel/vdso/vgettimeofday-32.o cc1: error: '-mpcrel' requires '-mcmodel=medium' make[2]: *** [arch/powerpc/kernel/vdso/Makefile:89: arch/powerpc/kernel/vdso/vgettimeofday-32.o] Error 1 make[1]: *** [arch/powerpc/Makefile:388: vdso_prepare] Error 2 make: *** [Makefile:251: __sub-make] Error 2 Make sure pcrel version of CFUNC() macro is used only for powerpc64 builds and remove -mpcrel for powerpc32 builds. Fixes: 7e3a68be42e1 ("powerpc/64: vmlinux support building with PCREL addresing") Signed-off-by: Christophe Leroy Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/1fa3453f07d42a50a70114da9905bf7b73304fca.1747073669.git.christophe.leroy@csgroup.eu

powerpc: Replace CONFIG_4xx with CONFIG_44x

2024-06-28T12:28:48Z

Replace 4xx usage with 44x, and replace 4xx_SOC with 44x. Also, as pointed out by Christophe, if 44x || BOOKE can be simplified to just test BOOKE, because 44x always selects BOOKE. Retain the CONFIG_4xx symbol, as there are drivers that use it to mean 4xx || 44x, those will need updating before CONFIG_4xx can be removed. Signed-off-by: Michael Ellerman Link: https://msgid.link/20240628121201.130802-6-mpe@ellerman.id.au

powerpc/64s: Use .machine power4 around dcbt

2024-03-03T12:05:21Z

There are multiple decodings for the "dcbt" mnemonic, so the assembler has to pick one. That requires passing -many to the assembler, which is not recommended. Without -many the clang 14 / binutils 2.38 build fails with: arch/powerpc/kernel/exceptions-64s.S:2976: Error: junk at end of line: `0b01010' clang: error: assembler command failed with exit code 1 (use -v to see invocation) Fix it by adding .machine directives around the use of dcbt to specify which encoding is desired. Acked-by: Segher Boessenkool Signed-off-by: Michael Ellerman Link: https://msgid.link/20240229122521.762431-2-mpe@ellerman.id.au

powerpc/64s: Move dcbt/dcbtst sequence into a macro

2024-03-03T12:05:21Z

There's an almost identical code sequence to specify load/store access hints in __copy_tofrom_user_power7(), copypage_power7() and memcpy_power7(). Move the sequence into a common macro, which is passed the registers to use as they differ slightly. There also needs to be a copy in the selftests, it could be shared in future if the headers are cleaned up / refactored. Signed-off-by: Michael Ellerman Link: https://msgid.link/20240229122521.762431-1-mpe@ellerman.id.au

powerpc/ps3: Fix lv1 hcall assembly for ELFv2 calling convention

2024-02-21T12:14:52Z

Stack-passed parameters begin at a different offset in the caller's stack in the ELFv2 ABI. Reported-by: Geoff Levand Fixes: 8c5fa3b5c4df ("powerpc/64: Make ELFv2 the default for big-endian builds") Signed-off-by: Nicholas Piggin Tested-by: Geoff Levand Signed-off-by: Michael Ellerman Link: https://msgid.link/20231227072405.63751-2-npiggin@gmail.com

powerpc: merge 32-bit and 64-bit _switch implementation

2023-06-15T04:03:55Z

The _switch stack frame setup are substantially the same, so are the comments. The difference in how the stack and current are switched, and other hardware and software housekeeping is done is moved into macros. Generated code should be unchanged. Signed-off-by: Nicholas Piggin [mpe: Tweak include orer to fix compile errors on some configs] Signed-off-by: Michael Ellerman Link: https://msgid.link/20230606132447.315714-6-npiggin@gmail.com

powerpc/64: modules support building with PCREL addresing

2023-04-20T03:21:42Z

Build modules using PCREL addressing when CONFIG_PPC_KERNEL_PCREL=y. - The module loader must handle several new relocation types: * R_PPC64_REL24_NOTOC is a function call handled like R_PPC_REL24, but does not restore r2 upon return. The external function call stub is changed to use pcrel addressing to load the function pointer rather than based on the module TOC. * R_PPC64_GOT_PCREL34 is a reference to external data. A GOT table must be built by hand, because the linker adds this during the final link (which is not done for kernel modules). The GOT table is built similarly to the way the external function call stub table is. This section is called .mygot because .got has a special meaning for the linker and can become upset. * R_PPC64_PCREL34 is used for local data addressing, but there is a special case where the percpu section is moved at load-time to the percpu area which is out of range of this relocation. This requires the PCREL34 relocations are converted to use GOT_PCREL34 addressing. Signed-off-by: Nicholas Piggin [mpe: Some coding style & formatting fixups] Signed-off-by: Michael Ellerman Link: https://msgid.link/20230408021752.862660-7-npiggin@gmail.com

powerpc/64: vmlinux support building with PCREL addresing

2023-04-20T02:59:21Z

PC-Relative or PCREL addressing is an extension to the ELF ABI which uses Power ISA v3.1 PC-relative instructions to calculate addresses, rather than the traditional TOC scheme. Add an option to build vmlinux using pcrel addressing. Modules continue to use TOC addressing. - TOC address helpers and r2 are poisoned with -1 when running vmlinux. r2 could be used for something useful once things are ironed out. - Assembly must call C functions with @notoc annotation, or the linker complains aobut a missing nop after the call. This is done with the CFUNC macro introduced earlier. - Boot: with the exception of prom_init, the execution branches to the kernel virtual address early in boot, before any addresses are generated, which ensures 34-bit pcrel addressing does not miss the high PAGE_OFFSET bits. TOC relative addressing has a similar requirement. prom_init does not go to the virtual address and its addresses should not carry over to the post-prom kernel. - Ftrace trampolines are converted from TOC addressing to pcrel addressing, including module ftrace trampolines that currently use the kernel TOC to find ftrace target functions. - BPF function prologue and function calling generation are converted from TOC to pcrel. - copypage_64.S has an interesting problem, prefixed instructions have alignment restrictions so the linker can add padding, which makes the assembler treat the difference between two local labels as non-constant even if alignment is arranged so padding is not required. This may need toolchain help to solve nicely, for now move the prefix instruction out of the alternate patch section to work around it. This reduces kernel text size by about 6%. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://msgid.link/20230408021752.862660-6-npiggin@gmail.com

powerpc: add CFUNC assembly label annotation

2023-04-20T02:54:24Z

This macro is to be used in assembly where C functions are called. pcrel addressing mode requires branches to functions with a localentry value of 1 to have either a trailing nop or @notoc. This macro permits the latter without changing callers. Signed-off-by: Nicholas Piggin [mpe: Add dummy definitions to fix selftests build] Signed-off-by: Michael Ellerman Link: https://msgid.link/20230408021752.862660-5-npiggin@gmail.com