kernel/linux.git/arch/powerpc/lib/sstep.c, branch v6.12.80

powerpc/sstep: make emulate_vsx_load and emulate_vsx_store static

2024-12-05T13:02:14+00:00

[ Upstream commit a26c4dbb3d9c1821cb0fc11cb2dbc32d5bf3463b ] These functions are not used outside of sstep.c Fixes: 350779a29f11 ("powerpc: Handle most loads and stores in instruction emulation code") Signed-off-by: Michal Suchanek Signed-off-by: Michael Ellerman Link: https://patch.msgid.link/20241001130356.14664-1-msuchanek@suse.de Signed-off-by: Sasha Levin

powerpc: Use user_mode() macro when possible

2024-02-22T10:55:33+00:00

There is a nice macro to check user mode. Use it instead of open coding anding with MSR_PR to increase readability and avoid having to comment what that anding is for. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://msgid.link/fbf74887dcf1f1ba9e1680fc3247cbb581b00662.1708078228.git.christophe.leroy@csgroup.eu

powerpc/lib: Validate size for vector operations

2023-11-27T11:06:19+00:00

Some of the fp/vmx code in sstep.c assume a certain maximum size for the instructions being emulated. The size of those operations however is determined separately in analyse_instr(). Add a check to validate the assumption on the maximum size of the operations, so as to prevent any unintended kernel stack corruption. Signed-off-by: Naveen N Rao Reviewed-by: Gustavo A. R. Silva Build-tested-by: Gustavo A. R. Silva Signed-off-by: Michael Ellerman Link: https://msgid.link/20231123071705.397625-1-naveen@kernel.org

powerpc/lib: Avoid array bounds warnings in vec ops

2023-11-27T11:05:14+00:00

Building with GCC with -Warray-bounds enabled there are several warnings in sstep.c along the lines of: In function ‘do_byte_reverse’, inlined from ‘do_vec_load’ at arch/powerpc/lib/sstep.c:691:3, inlined from ‘emulate_loadstore’ at arch/powerpc/lib/sstep.c:3439:9: arch/powerpc/lib/sstep.c:289:23: error: array subscript 2 is outside array bounds of ‘u8[16]’ {aka ‘unsigned char[16]’} [-Werror=array-bounds=] 289 | up[2] = byterev_8(up[1]); | ~~~~~~^~~~~~~~~~~~~~~~~~ arch/powerpc/lib/sstep.c: In function ‘emulate_loadstore’: arch/powerpc/lib/sstep.c:681:11: note: at offset 16 into object ‘u’ of size 16 681 | } u = {}; | ^ do_byte_reverse() supports a size up to 32 bytes, but in these cases the caller is only passing a 16 byte buffer. In practice there is no bug, do_vec_load() is only called from the LOAD_VMX case in emulate_loadstore(). That in turn is only reached when analyse_instr() recognises VMX ops, and in all cases the size is no greater than 16: $ git grep -w LOAD_VMX arch/powerpc/lib/sstep.c arch/powerpc/lib/sstep.c: op->type = MKOP(LOAD_VMX, 0, 1); arch/powerpc/lib/sstep.c: op->type = MKOP(LOAD_VMX, 0, 2); arch/powerpc/lib/sstep.c: op->type = MKOP(LOAD_VMX, 0, 4); arch/powerpc/lib/sstep.c: op->type = MKOP(LOAD_VMX, 0, 16); Similarly for do_vec_store(). Although the warning is incorrect, the code would be safer if it clamped the size from the caller to the known size of the buffer. Do that using min_t(). Reported-by: Bagas Sanjaya Closes: https://lore.kernel.org/linuxppc-dev/YpbUcPrm61RLIiZF@debian.me/ Reported-by: Jan-Benedict Glaw Closes: https://lore.kernel.org/linuxppc-dev/20221212215117.aa7255t7qd6yefk4@lug-owl.de/ Reported-by: "Gustavo A. R. Silva" Closes: https://lore.kernel.org/linuxppc-dev/6a8bf78c-aedb-4d5a-b0aa-82a51a17b884@embeddedor.com/ Reviewed-by: "Gustavo A. R. Silva" Build-tested-by: "Gustavo A. R. Silva" Signed-off-by: Michael Ellerman Link: https://msgid.link/20231120235436.1569255-1-mpe@ellerman.id.au

powerpc/step: Mark __copy_mem_out() and __emulate_dcbz() __always_inline

2023-08-16T13:54:48+00:00

objtool reports two folliwng warnings: arch/powerpc/lib/sstep.o: warning: objtool: copy_mem_out+0x3c (.text+0x30c): call to __copy_mem_out() with UACCESS enabled arch/powerpc/lib/sstep.o: warning: objtool: emulate_dcbz+0x70 (.text+0x4dc): call to __emulate_dcbz() with UACCESS enabled Mark __copy_mem_out() and __emulate_dcbz() __always_inline Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://msgid.link/f1d4a15da70190f8c2fcddb377bbc1e09827242c.1687343857.git.christophe.leroy@csgroup.eu

powerpc: add compile-time support for lbarx, lharx

2022-11-24T12:31:47+00:00

ISA v2.06 (POWER7 and up) as well as e6500 support lbarx and lharx. Add a compile option that allows code to use it, and add support in cmpxchg and xchg 8 and 16 bit values without shifting and masking. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220909052312.63916-1-npiggin@gmail.com

powerpc/64: remove system call instruction emulation

2022-05-05T14:00:20+00:00

emulate_step() instruction emulation including sc instruction emulation initially appeared in xmon. It was then moved into sstep.c where kprobes could use it too, and later hw_breakpoint and uprobes started to use it. Until uprobes, the only instruction emulation users were for kernel mode instructions. - xmon only steps / breaks on kernel addresses. - kprobes is kernel only. - hw_breakpoint only emulates kernel instructions, single steps user. At one point, there was support for the kernel to execute sc instructions, although that is long removed and it's not clear whether there were any in-tree users. So system call emulation is not required by the above users. uprobes uses emulate_step and it appears possible to emulate sc instruction in userspace. Userspace system call emulation is broken and it's not clear it ever worked well. The big complication is that userspace takes an interrupt to the kernel to emulate the instruction. The user->kernel interrupt sets up registers and interrupt stack frame expecting to return to userspace, then system call instruction emulation re-directs that stack frame to the kernel, early in the system call interrupt handler. This means the interrupt return code takes the kernel->kernel restore path, which does not restore everything as the system call interrupt handler would expect coming from userspace. regs->iamr appears to get lost for example, because the kernel->kernel return does not restore the user iamr. Accounting such as irqflags tracing and CPU accounting does not get flipped back to user mode as the system call handler expects, so those appear to enter the kernel twice without returning to userspace. These things may be individually fixable with various complication, but it is a big complexity for unclear real benefit. Furthermore, it is not possible to single step a system call instruction since it causes an interrupt. As such, a separate patch disables probing on system call instructions. This patch removes system call emulation and disables stepping system calls. Signed-off-by: Nicholas Piggin [minor commit log edit, and also get rid of '#ifdef CONFIG_PPC64'] Signed-off-by: Naveen N. Rao Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/a412e3b3791ed83de18704c8d90f492e7a0049c0.1648648712.git.naveen.n.rao@linux.vnet.ibm.com

powerpc/sstep: Use bitwise instead of arithmetic operator for flags

2022-05-02T13:02:15+00:00

Fix the following coccinelle warnings: ./arch/powerpc/lib/sstep.c:1090:20-21: WARNING: sum of probable bitmasks, consider | ./arch/powerpc/lib/sstep.c:1115:20-21: WARNING: sum of probable bitmasks, consider | ./arch/powerpc/lib/sstep.c:1134:20-21: WARNING: sum of probable bitmasks, consider | Reported-by: Abaci Robot Signed-off-by: Yang Li Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/1613811455-2457-1-git-send-email-yang.lee@linux.alibaba.com

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

2022-03-25T16:39:36+00:00

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 ...

Merge tag 'asm-generic-5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic

2022-03-24T01:03:08+00:00

Pull asm-generic updates from Arnd Bergmann: "There are three sets of updates for 5.18 in the asm-generic tree: - The set_fs()/get_fs() infrastructure gets removed for good. This was already gone from all major architectures, but now we can finally remove it everywhere, which loses some particularly tricky and error-prone code. There is a small merge conflict against a parisc cleanup, the solution is to use their new version. - The nds32 architecture ends its tenure in the Linux kernel. The hardware is still used and the code is in reasonable shape, but the mainline port is not actively maintained any more, as all remaining users are thought to run vendor kernels that would never be updated to a future release. - A series from Masahiro Yamada cleans up some of the uapi header files to pass the compile-time checks" * tag 'asm-generic-5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic: (27 commits) nds32: Remove the architecture uaccess: remove CONFIG_SET_FS ia64: remove CONFIG_SET_FS support sh: remove CONFIG_SET_FS support sparc64: remove CONFIG_SET_FS support lib/test_lockup: fix kernel pointer check for separate address spaces uaccess: generalize access_ok() uaccess: fix type mismatch warnings from access_ok() arm64: simplify access_ok() m68k: fix access_ok for coldfire MIPS: use simpler access_ok() MIPS: Handle address errors for accesses above CPU max virtual user address uaccess: add generic __{get,put}_kernel_nofault nios2: drop access_ok() check from __put_user() x86: use more conventional access_ok() definition x86: remove __range_not_ok() sparc64: add __{get,put}_kernel_nofault() nds32: fix access_ok() checks in get/put_user uaccess: fix nios2 and microblaze get_user_8() sparc64: fix building assembly files ...