MIPS: Clear Cause.BD in instruction_pointer_set Clear Cause.BD after we use instruction_pointer_set to override EPC. This can prevent exception_epc check against instruction code at new return address. It won't be considered as "in delay slot" after epc being overridden anyway. Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
ptrace: Introduce exception_ip arch hook On architectures with delay slot, architecture level instruction pointer (or program counter) in pt_regs may differ from where exception was triggered. Introduce exception_ip hook to invoke architecture code and determine actual instruction pointer to the exception. Link: https://lore.kernel.org/lkml/00d1b813-c55f-4365-8d81-d70258e10b16@app.fastmail.com/ Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Revert "MIPS: Add basic support for ptrace single step" This reverts commit 7c86ff9925cbc83e8a21f164a8fdc2767e03531e. There are too many special cases for MIPS not covered by this patch. In the end it might be better to implement single stepping in userland than emulating it in the kernel. Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
MIPS: Add basic support for ptrace single step In the current code, arch_has_single_step() is not defined on MIPS, that means MIPS does not support instruction single-step for user mode. Delve is a debugger for the Go programming language, the ptrace syscall PtraceSingleStep() failed [1] on MIPS and then the single step function can not work well, we can see that PtraceSingleStep() definition returns ptrace(PTRACE_SINGLESTEP) [2]. So it is necessary to support ptrace single step on MIPS. At the beginning, we try to use the Debug Single Step exception on the Loongson 3A4000 platform, but it has no effect when set CP0_DEBUG SSt bit, this is because CP0_DEBUG NoSSt bit is 1 which indicates no single-step feature available [3], so this way which is dependent on the hardware is almost impossible. With further research, we find out there exists a common way used with break instruction in arch/alpha/kernel/ptrace.c, it is workable. For the above analysis, define arch_has_single_step(), add the common function user_enable_single_step() and user_disable_single_step(), set flag TIF_SINGLESTEP for child process, use break instruction to set breakpoint. We can use the following testcase to test it: tools/testing/selftests/breakpoints/step_after_suspend_test.c $ make -C tools/testing/selftests TARGETS=breakpoints $ cd tools/testing/selftests/breakpoints Without this patch: $ ./step_after_suspend_test -n TAP version 13 1..4 # ptrace(PTRACE_SINGLESTEP) not supported on this architecture: Input/output error ok 1 # SKIP CPU 0 # ptrace(PTRACE_SINGLESTEP) not supported on this architecture: Input/output error ok 2 # SKIP CPU 1 # ptrace(PTRACE_SINGLESTEP) not supported on this architecture: Input/output error ok 3 # SKIP CPU 2 # ptrace(PTRACE_SINGLESTEP) not supported on this architecture: Input/output error ok 4 # SKIP CPU 3 # Totals: pass:0 fail:0 xfail:0 xpass:0 skip:4 error:0 With this patch: $ ./step_after_suspend_test -n TAP version 13 1..4 ok 1 CPU 0 ok 2 CPU 1 ok 3 CPU 2 ok 4 CPU 3 # Totals: pass:4 fail:0 xfail:0 xpass:0 skip:0 error:0 [1] https://github.com/go-delve/delve/blob/master/pkg/proc/native/threads_linux.go#L50 [2] https://github.com/go-delve/delve/blob/master/vendor/golang.org/x/sys/unix/syscall_linux.go#L1573 [3] http://www.t-es-t.hu/download/mips/md00047f.pdf Reported-by: Guoqi Chen <chenguoqi@loongson.cn> Signed-off-by: Xingxing Su <suxingxing@loongson.cn> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
MIPS: fix kernel_stack_pointer() MIPS always save kernel stack pointer in regs[29] Signed-off-by: Huang Pei <huangpei@loongson.cn> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
asm-generic: remove ptrace.h No one is using this header anymore. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Paul Burton <paul.burton@mips.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
MIPS: ptrace: Fix regs_return_value for kernel context Currently regs_return_value always negates reg[2] if it determines the syscall has failed, but when called in kernel context this check is invalid and may result in returning a wrong value. This fixes errors reported by CONFIG_KPROBES_SANITY_TEST Fixes: d7e7528bcd45 ("Audit: push audit success and retcode into arch ptrace.h") Signed-off-by: Marcin Nowakowski <marcin.nowakowski@imgtec.com> Cc: linux-mips@linux-mips.org Cc: stable@vger.kernel.org # 3.3+ Patchwork: https://patchwork.linux-mips.org/patch/14381/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
MIPS: Add uprobes support. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
MIPS: OCTEON: Save/Restore wider multiply registers in OCTEON III CPUs The wide multiplier is twice as wide, so we need to save twice as much state. Detect the multiplier type (CPU type) at start up and install model specific handlers. [aleksey.makarov@auriga.com: conflict resolution, support for old compilers] Signed-off-by: David Daney <david.daney@cavium.com> Signed-off-by: Leonid Rosenboim <lrosenboim@caviumnetworks.com> Signed-off-by: Aleksey Makarov <aleksey.makarov@auriga.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/8933/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
MIPS: ptrace: Fix user pt_regs definition, use in ptrace_{get, set}regs() In uapi/asm/ptrace.h, a user version of pt_regs is defined wrapped in ifndef __KERNEL__. This structure definition does not match anything used by any kernel API, in particular it does not match the format used by PTRACE_{GET,SET}REGS. Therefore, replace the structure definition with one matching what is used by PTRACE_{GET,SET}REGS. The format used by these is the same for both 32-bit and 64-bit. Also, change the implementation of PTRACE_{GET,SET}REGS to use this new structure definition. The structure is renamed to user_pt_regs when __KERNEL__ is defined to avoid conflicts with the kernel's own pt_regs. Signed-off-by: Alex Smith <alex@alex-smith.me.uk> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/7457/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
MIPS: O32/32-bit: Fix bug which can cause incorrect system call restarts On 32-bit/O32, pt_regs has a padding area at the beginning into which the syscall arguments passed via the user stack are copied. 4 arguments totalling 16 bytes are copied to offset 16 bytes into this area, however the area is only 24 bytes long. This means the last 2 arguments overwrite pt_regs->regs[{0,1}]. If a syscall function returns an error, handle_sys stores the original syscall number in pt_regs->regs[0] for syscall restart. signal.c checks whether regs[0] is non-zero, if it is it will check whether the syscall return value is one of the ERESTART* codes to see if it must be restarted. Should a syscall be made that results in a non-zero value being copied off the user stack into regs[0], and then returns a positive (non-error) value that matches one of the ERESTART* error codes, this can be mistaken for requiring a syscall restart. While the possibility for this to occur has always existed, it is made much more likely to occur by commit 46e12c07b3b9 ("MIPS: O32 / 32-bit: Always copy 4 stack arguments."), since now every syscall will copy 4 arguments and overwrite regs[0], rather than just those with 7 or 8 arguments. Since that commit, booting Debian under a 32-bit MIPS kernel almost always results in a hang early in boot, due to a wait4 syscall returning a PID that matches one of the ERESTART* codes, which then causes an incorrect restart of the syscall. The problem is fixed by increasing the size of the padding area so that arguments copied off the stack will not overwrite pt_regs->regs[{0,1}]. Signed-off-by: Alex Smith <alex.smith@imgtec.com> Cc: <stable@vger.kernel.org> # v3.13+ Reviewed-by: Aurelien Jarno <aurelien@aurel32.net> Tested-by: Aurelien Jarno <aurelien@aurel32.net> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/7454/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
MIPS: MT: Remove SMTC support Nobody is maintaining SMTC anymore and there also seems to be no userbase. Which is a pity - the SMTC technology primarily developed by Kevin D. Kissell <kevink@paralogos.com> is an ingenious demonstration for the MT ASE's power and elegance. Based on Markos Chandras <Markos.Chandras@imgtec.com> patch https://patchwork.linux-mips.org/patch/6719/ which while very similar did no longer apply cleanly when I tried to merge it plus some additional post-SMTC cleanup - SMTC was a feature as tricky to remove as it was to merge once upon a time. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
MIPS: seccomp: Handle indirect system calls (o32) When userland uses syscall() to perform an indirect system call the actually system call that needs to be checked by the filter is on the first argument. The kernel code needs to handle this case by looking at the original syscall number in v0 and if it's NR_syscall, then it needs to examine the first argument to identify the real system call that will be executed. Similarly, we need to 'virtually' shift the syscall() arguments so the syscall_get_arguments() function can fetch the correct arguments for the indirect system call. Signed-off-by: Markos Chandras <markos.chandras@imgtec.com> Reviewed-by: James Hogan <james.hogan@imgtec.com> Reviewed-by: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/6404/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
MIPS: ptrace: Move away from secure_computing_strict MIPS now has the infrastructure for dynamic seccomp-bpf filtering Signed-off-by: Markos Chandras <markos.chandras@imgtec.com> Reviewed-by: James Hogan <james.hogan@imgtec.com> Reviewed-by: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/6400/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
MIPS: Enable HAVE_ARCH_TRACEHOOK. This enables /proc/<pid>/syscall and the ptrace PTRACE_GETREGSET and PTRACE_SETREGSET operations. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
MIPS: Quit exposing Kconfig symbols in uapi headers. The kernel's struct pt_regs has many fields conditional on various Kconfig variables, we cannot be exporting this garbage to user-space. Move the kernel's definition to asm/ptrace.h, and put a uapi only version in uapi/asm/ptrace.h gated by #ifndef __KERNEL__ Signed-off-by: David Daney <david.daney@cavium.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/5305/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
missing user_stack_pointer() instances for the architectures that have usp in pt_regs and do not have user_stack_pointer() already defined. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
MIPS: Switch over to generic sys_execve and kernel_execve. This version contains a few updates by David Daney, in particular it's now using __builtin_frame_address() instead of asm() which depending on personal taste, is slightly more appealing. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
UAPI: (Scripted) Disintegrate arch/mips/include/asm Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Michael Kerrisk <mtk.manpages@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Dave Jones <davej@redhat.com>
Merge branch 'for-linus' of git://git./linux/kernel/git/viro/audit * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit: (29 commits) audit: no leading space in audit_log_d_path prefix audit: treat s_id as an untrusted string audit: fix signedness bug in audit_log_execve_info() audit: comparison on interprocess fields audit: implement all object interfield comparisons audit: allow interfield comparison between gid and ogid audit: complex interfield comparison helper audit: allow interfield comparison in audit rules Kernel: Audit Support For The ARM Platform audit: do not call audit_getname on error audit: only allow tasks to set their loginuid if it is -1 audit: remove task argument to audit_set_loginuid audit: allow audit matching on inode gid audit: allow matching on obj_uid audit: remove audit_finish_fork as it can't be called audit: reject entry,always rules audit: inline audit_free to simplify the look of generic code audit: drop audit_set_macxattr as it doesn't do anything audit: inline checks for not needing to collect aux records audit: drop some potentially inadvisable likely notations ... Use evil merge to fix up grammar mistakes in Kconfig file. Bad speling and horrible grammar (and copious swearing) is to be expected, but let's keep it to commit messages and comments, rather than expose it to users in config help texts or printouts.