kernel.git/arch/powerpc/kernel/exceptions-64e.S, branch linux-6.1.y

powerpc/64/interrupt: Prevent NMI PMI causing a dangerous warning

2022-10-18T11:46:19Z

NMI PMIs really should not return using the normal interrupt_return function. If such a PMI hits in code returning to user with the context switched to user mode, this warning can fire. This was enough to cause crashes when reproducing on 64s, because another perf interrupt would hit while reporting bug, and that would cause another bug, and so on until smashing the stack. Work around that particular crash for now by just disabling that context warning for PMIs. This is a hack and not a complete fix, there could be other such problems lurking in corners. But it does fix the known crash. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20221014030729.2077151-3-npiggin@gmail.com

powerpc/64e: provide an addressing macro for use with TOC in alternate register

2022-09-28T09:22:12Z

The interrupt entry code carefully saves a minimal number of registers, so in some places the TOC is required, it is loaded into a different register, so provide a macro that can supply an alternate TOC register. This continues to use got addressing because TOC-relative results in "got/toc optimization is not supported" messages by the linker. Having r2 be one of the saved registers and using that for TOC addressing may be the best way to avoid that and switch this to TOC addressing. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220926034057.2360083-6-npiggin@gmail.com

powerpc/64: provide a helper macro to load r2 with the kernel TOC

2022-09-28T09:22:12Z

A later change stops the kernel using r2 and loads it with a poison value. Provide a PACATOC loading abstraction which can hide this detail. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220926034057.2360083-5-npiggin@gmail.com

powerpc/64: use 32-bit immediate for STACK_FRAME_REGS_MARKER

2022-09-28T09:22:12Z

Using a 32-bit constant for this marker allows it to be loaded with two ALU instructions, like 32-bit. This avoids a TOC entry and a TOC load that depends on the r2 value that has just been loaded from the PACA. This changes the value for 32-bit as well, so both have the same value in the low 4 bytes and 64-bit has 0 in the top bytes. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220926034057.2360083-2-npiggin@gmail.com

powerpc/64e: Clarify register saves and clears with {SAVE,ZEROIZE}_GPRS

2022-09-26T13:00:15Z

The common interrupt handler prologue macro and the bad_stack trampolines include consecutive sequences of register saves, and some register clears. Neaten such instances by expanding use of the SAVE_GPRS macro and employing the ZEROIZE_GPR macro when appropriate. Also simplify an invocation of SAVE_GPRS targetting all non-volatile registers to SAVE_NVGPRS. Signed-off-by: Rohan McLure Reported-by: Nicholas Piggin Reviewed-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220921065605.1051927-7-rmclure@linux.ibm.com

powerpc/64e: Remove unnecessary #ifdef CONFIG_PPC_FSL_BOOK3E

2022-09-26T11:00:41Z

CONFIG_PPC_BOOK3E_64 implies CONFIG_PPC_FSL_BOOK3E so no need of additional #ifdefs in files built exclusively for CONFIG_PPC_BOOK3E_64. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/df16255c13b63b0221c9be63b94a6864bed22c12.1663606875.git.christophe.leroy@csgroup.eu

powerpc: flexible GPR range save/restore macros

2021-11-29T12:15:20Z

Introduce macros that operate on a (start, end) range of GPRs, which reduces lines of code and need to do mental arithmetic while reading the code. Signed-off-by: Nicholas Piggin Reviewed-by: Segher Boessenkool Reviewed-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20211022061322.2671178-1-npiggin@gmail.com

powerpc/64e: Get dear offset with _DEAR macro

2021-08-26T11:21:07Z

Use _DEAR to get the offset of dear register in pr_regs for 64e cpus. Signed-off-by: Xiongwei Song Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20210807010239.416055-5-sxwjean@me.com

powerpc/64e: Get esr offset with _ESR macro

2021-08-26T11:21:07Z

Use _ESR to get the offset of esr register in pr_regs for 64e cpus. Signed-off-by: Xiongwei Song Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20210807010239.416055-3-sxwjean@me.com

powerpc/booke: Avoid link stack corruption in several places

2021-08-25T03:35:47Z

Use bcl 20,31,+4 instead of bl in order to preserve link stack. See commit c974809a26a1 ("powerpc/vdso: Avoid link stack corruption in __get_datapage()") for details. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/e9fbc285eceb720e6c0e032ef47fe8b05f669b48.1629791751.git.christophe.leroy@csgroup.eu