kernel.git/arch/powerpc/kernel/optprobes.c, branch linux-5.13.y

powerpc: Enable OPTPROBES on PPC32

2021-04-21T12:52:32Z

For that, create a 32 bits version of patch_imm64_load_insns() and create a patch_imm_load_insns() which calls patch_imm32_load_insns() on PPC32 and patch_imm64_load_insns() on PPC64. Adapt optprobes_head.S for PPC32. Use PPC_LL/PPC_STL macros instead of raw ld/std, opt out things linked to paca and use stmw/lmw to save/restore registers. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/bad58c66859b2a475c0ad516b53164ae3b4853cd.1618927318.git.christophe.leroy@csgroup.eu

powerpc/inst: ppc_inst_as_u64() becomes ppc_inst_as_ulong()

2021-04-21T12:52:32Z

In order to simplify use on PPC32, change ppc_inst_as_u64() into ppc_inst_as_ulong() that returns the 32 bits instruction on PPC32. Will be used when porting OPTPROBES to PPC32. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/22cadf29620664b600b82026d2a72b8b23351777.1618927318.git.christophe.leroy@csgroup.eu

powerpc/optprobes: Make patch_imm64_load_insns() static

2021-01-30T00:39:29Z

patch_imm64_load_insns() is only used locally in arch_prepare_optimized_kprobe() and does not need to be external. It fixes this W=1 compile error : ../arch/powerpc/kernel/optprobes.c:149:6: error: no previous prototype for ‘patch_imm64_load_insns’ [-Werror=missing-prototypes] 149 | void patch_imm64_load_insns(unsigned int val, kprobe_opcode_t *addr) Signed-off-by: Cédric Le Goater Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20210104143206.695198-12-clg@kaod.org

powerpc/optprobes: Remove unused routine patch_imm32_load_insns()

2021-01-30T00:39:29Z

Commit 650b55b707fd ("powerpc: Add prefixed instructions to instruction data type") removed the use of patch_imm32_load_insns(). Clean it up to fix this W=1 compile error : ../arch/powerpc/kernel/optprobes.c:149:6: error: no previous prototype for ‘patch_imm32_load_insns’ [-Werror=missing-prototypes] 149 | void patch_imm32_load_insns(unsigned int val, kprobe_opcode_t *addr) Fixes: 650b55b707fd ("powerpc: Add prefixed instructions to instruction data type") Signed-off-by: Cédric Le Goater Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20210104143206.695198-11-clg@kaod.org

powerpc: Add ppc_inst_as_u64()

2020-05-26T13:36:57Z

The code patching code wants to get the value of a struct ppc_inst as a u64 when the instruction is prefixed, so we can pass the u64 down to __put_user_asm() and write it with a single store. The optprobes code wants to load a struct ppc_inst as an immediate into a register so it is useful to have it as a u64 to use the existing helper function. Currently this is a bit awkward because the value differs based on the CPU endianness, so add a helper to do the conversion. This fixes the usage in arch_prepare_optimized_kprobe() which was previously incorrect on big endian. Fixes: 650b55b707fd ("powerpc: Add prefixed instructions to instruction data type") Signed-off-by: Michael Ellerman Tested-by: Jordan Niethe Link: https://lore.kernel.org/r/20200526072630.2487363-1-mpe@ellerman.id.au

powerpc: Add prefixed instructions to instruction data type

2020-05-18T14:10:39Z

For powerpc64, redefine the ppc_inst type so both word and prefixed instructions can be represented. On powerpc32 the type will remain the same. Update places which had assumed instructions to be 4 bytes long. Signed-off-by: Jordan Niethe Reviewed-by: Alistair Popple [mpe: Rework the get_user_inst() macros to be parameterised, and don't assign to the dest if an error occurred. Use CONFIG_PPC64 not __powerpc64__ in a few places. Address other comments from Christophe. Fix some sparse complaints.] Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200506034050.24806-24-jniethe5@gmail.com

powerpc/optprobes: Add register argument to patch_imm64_load_insns()

2020-05-18T14:10:38Z

Currently patch_imm32_load_insns() is used to load an instruction to r4 to be emulated by emulate_step(). For prefixed instructions we would like to be able to load a 64bit immediate to r4. To prepare for this make patch_imm64_load_insns() take an argument that decides which register to load an immediate to - rather than hardcoding r3. Signed-off-by: Jordan Niethe Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200516115449.4168796-1-mpe@ellerman.id.au

powerpc: Use a function for reading instructions

2020-05-18T14:10:37Z

Prefixed instructions will mean there are instructions of different length. As a result dereferencing a pointer to an instruction will not necessarily give the desired result. Introduce a function for reading instructions from memory into the instruction data type. Signed-off-by: Jordan Niethe Signed-off-by: Michael Ellerman Reviewed-by: Alistair Popple Link: https://lore.kernel.org/r/20200506034050.24806-13-jniethe5@gmail.com

powerpc: Use a datatype for instructions

2020-05-18T14:10:37Z

Currently unsigned ints are used to represent instructions on powerpc. This has worked well as instructions have always been 4 byte words. However, ISA v3.1 introduces some changes to instructions that mean this scheme will no longer work as well. This change is Prefixed Instructions. A prefixed instruction is made up of a word prefix followed by a word suffix to make an 8 byte double word instruction. No matter the endianness of the system the prefix always comes first. Prefixed instructions are only planned for powerpc64. Introduce a ppc_inst type to represent both prefixed and word instructions on powerpc64 while keeping it possible to exclusively have word instructions on powerpc32. Signed-off-by: Jordan Niethe [mpe: Fix compile error in emulate_spe()] Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200506034050.24806-12-jniethe5@gmail.com

powerpc: Use a macro for creating instructions from u32s

2020-05-18T14:10:36Z

In preparation for instructions having a more complex data type start using a macro, ppc_inst(), for making an instruction out of a u32. A macro is used so that instructions can be used as initializer elements. Currently this does nothing, but it will allow for creating a data type that can represent prefixed instructions. Signed-off-by: Jordan Niethe [mpe: Change include guard to _ASM_POWERPC_INST_H] Signed-off-by: Michael Ellerman Reviewed-by: Alistair Popple Link: https://lore.kernel.org/r/20200506034050.24806-7-jniethe5@gmail.com