kernel.git/arch/mips/kernel/ptrace.c, branch linux-4.18.y

MIPS: Correct the 64-bit DSP accumulator register size

2018-09-05T07:29:53Z

commit f5958b4cf4fc38ed4583ab83fb7c4cd1ab05f47b upstream. Use the `unsigned long' rather than `__u32' type for DSP accumulator registers, like with the regular MIPS multiply/divide accumulator and general-purpose registers, as all are 64-bit in 64-bit implementations and using a 32-bit data type leads to contents truncation on context saving. Update `arch_ptrace' and `compat_arch_ptrace' accordingly, removing casts that are similarly not used with multiply/divide accumulator or general-purpose register accesses. Signed-off-by: Maciej W. Rozycki Signed-off-by: Paul Burton Fixes: e50c0a8fa60d ("Support the MIPS32 / MIPS64 DSP ASE.") Patchwork: https://patchwork.linux-mips.org/patch/19329/ Cc: Alexander Viro Cc: James Hogan Cc: Ralf Baechle Cc: linux-fsdevel@vger.kernel.org Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Cc: stable@vger.kernel.org # 2.6.15+ Signed-off-by: Greg Kroah-Hartman

Merge tag 'mips_4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux

2018-06-12T19:56:02Z

Pull MIPS updates from James Hogan: "These are the main MIPS changes for 4.18. Rough overview: - MAINTAINERS: Add Paul Burton as MIPS co-maintainer - Misc: Generic compiler intrinsics, Y2038 improvements, Perf+MT fixes - Platform support: Netgear WNR1000 V3, Microsemi Ocelot integrated switch, Ingenic watchdog cleanups More detailed summary: Maintainers: - Add Paul Burton as MIPS co-maintainer, as I soon won't have access to much MIPS hardware, nor enough time to properly maintain MIPS on my own. Miscellaneous: - Use generic GCC library routines from lib/ - Add notrace to generic ucmpdi2 implementation - Rename compiler intrinsic selects to GENERIC_LIB_* - vmlinuz: Use generic ashldi3 - y2038: Convert update/read_persistent_clock() to *_clock64() - sni: Remove read_persistent_clock() - perf: Fix perf with MT counting other threads - Probe for per-TC perf counters in cpu-probe.c - Use correct VPE ID for VPE tracing Minor cleanups: - Avoid unneeded built-in.a in DTS dirs - sc-debugfs: Re-use kstrtobool_from_user - memset.S: Reinstate delay slot indentation - VPE: Fix spelling "uneeded" -> "Unneeded" Platform support: BCM47xx: - Add support for Netgear WNR1000 V3 - firmware: Support small NVRAM partitions - Use __initdata for LEDs platform data Ingenic: - Watchdog driver & platform code improvements: - Disable clock after stopping counter - Use devm_* functions - Drop module remove function - Move platform reset code to restart handler in driver - JZ4740: Convert watchdog instantiation to DT - JZ4780: Fix watchdog DT node - qi_lb60_defconfig: Enable watchdog driver Microsemi: - Ocelot: Add support for integrated switch - pcb123: Connect phys to ports" * tag 'mips_4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux: (30 commits) MAINTAINERS: Add Paul Burton as MIPS co-maintainer MIPS: ptrace: Make FPU context layout comments match reality MIPS: memset.S: Reinstate delay slot indentation MIPS: perf: Fix perf with MT counting other threads MIPS: perf: Use correct VPE ID when setting up VPE tracing MIPS: perf: More robustly probe for the presence of per-tc counters MIPS: Probe for MIPS MT perf counters per TC MIPS: mscc: Connect phys to ports on ocelot_pcb123 MIPS: mscc: Add switch to ocelot MIPS: JZ4740: Drop old platform reset code MIPS: qi_lb60: Enable the jz4740-wdt driver MIPS: JZ4780: dts: Fix watchdog node MIPS: JZ4740: dts: Add bindings for the jz4740-wdt driver watchdog: JZ4740: Drop module remove function watchdog: JZ4740: Register a restart handler watchdog: JZ4740: Use devm_* functions watchdog: JZ4740: Disable clock after stopping counter MIPS: VPE: Fix spelling mistake: "uneeded" -> "unneeded" MIPS: Re-use kstrtobool_from_user() MIPS: Convert update_persistent_clock() to update_persistent_clock64() ...

MIPS: ptrace: Fix PTRACE_PEEKUSR requests for 64-bit FGRs

2018-05-24T13:03:14Z

Use 64-bit accesses for 64-bit floating-point general registers with PTRACE_PEEKUSR, removing the truncation of their upper halves in the FR=1 mode, caused by commit bbd426f542cb ("MIPS: Simplify FP context access"), which inadvertently switched them to using 32-bit accesses. The PTRACE_POKEUSR side is fine as it's never been broken and continues using 64-bit accesses. Fixes: bbd426f542cb ("MIPS: Simplify FP context access") Signed-off-by: Maciej W. Rozycki Cc: Ralf Baechle Cc: linux-mips@linux-mips.org Cc: # 3.15+ Patchwork: https://patchwork.linux-mips.org/patch/19334/ Signed-off-by: James Hogan

MIPS: ptrace: Make FPU context layout comments match reality

2018-05-24T12:37:07Z

Correct comments across ptrace(2) handlers about an FPU register context layout discrepancy between MIPS I and later ISAs, which was fixed with `linux-mips.org' (LMO) commit 42533948caac ("Major pile of FP emulator changes."), the fix corrected with LMO commit 849fa7a50dff ("R3k FPU ptrace() handling fixes."), and then broken and fixed over and over again, until last time fixed with commit 80cbfad79096 ("MIPS: Correct MIPS I FP context layout"). NB running the GDB test suite for the relevant ABI/ISA and watching out for regressions is advisable when poking around ptrace(2). Signed-off-by: Maciej W. Rozycki Cc: Ralf Baechle Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/19326/ Signed-off-by: James Hogan

MIPS: Fix ptrace(2) PTRACE_PEEKUSR and PTRACE_POKEUSR accesses to o32 FGRs

2018-05-14T22:54:25Z

Check the TIF_32BIT_FPREGS task setting of the tracee rather than the tracer in determining the layout of floating-point general registers in the floating-point context, correcting access to odd-numbered registers for o32 tracees where the setting disagrees between the two processes. Fixes: 597ce1723e0f ("MIPS: Support for 64-bit FP with O32 binaries") Signed-off-by: Maciej W. Rozycki Cc: Ralf Baechle Cc: linux-mips@linux-mips.org Cc: # 3.14+ Signed-off-by: James Hogan

MIPS: ptrace: Expose FIR register through FP regset

2018-05-14T22:54:25Z

Correct commit 7aeb753b5353 ("MIPS: Implement task_user_regset_view.") and expose the FIR register using the unused 4 bytes at the end of the NT_PRFPREG regset. Without that register included clients cannot use the PTRACE_GETREGSET request to retrieve the complete FPU register set and have to resort to one of the older interfaces, either PTRACE_PEEKUSR or PTRACE_GETFPREGS, to retrieve the missing piece of data. Also the register is irreversibly missing from core dumps. This register is architecturally hardwired and read-only so the write path does not matter. Ignore data supplied on writes then. Fixes: 7aeb753b5353 ("MIPS: Implement task_user_regset_view.") Signed-off-by: James Hogan Signed-off-by: Maciej W. Rozycki Cc: Ralf Baechle Cc: linux-mips@linux-mips.org Cc: # 3.13+ Patchwork: https://patchwork.linux-mips.org/patch/19273/ Signed-off-by: James Hogan

MIPS: Disallow outsized PTRACE_SETREGSET NT_PRFPREG regset accesses

2017-12-12T18:14:12Z

Complement commit c23b3d1a5311 ("MIPS: ptrace: Change GP regset to use correct core dump register layout") and also reject outsized PTRACE_SETREGSET requests to the NT_PRFPREG regset, like with the NT_PRSTATUS regset. Signed-off-by: Maciej W. Rozycki Fixes: c23b3d1a5311 ("MIPS: ptrace: Change GP regset to use correct core dump register layout") Cc: James Hogan Cc: Paul Burton Cc: Alex Smith Cc: Dave Martin Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Cc: stable@vger.kernel.org # v3.17+ Patchwork: https://patchwork.linux-mips.org/patch/17930/ Signed-off-by: Ralf Baechle

MIPS: Also verify sizeof `elf_fpreg_t' with PTRACE_SETREGSET

2017-12-12T18:13:42Z

Complement commit d614fd58a283 ("mips/ptrace: Preserve previous registers for short regset write") and like with the PTRACE_GETREGSET ptrace(2) request also apply a BUILD_BUG_ON check for the size of the `elf_fpreg_t' type in the PTRACE_SETREGSET request handler. Signed-off-by: Maciej W. Rozycki Fixes: d614fd58a283 ("mips/ptrace: Preserve previous registers for short regset write") Cc: James Hogan Cc: Paul Burton Cc: Alex Smith Cc: Dave Martin Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Cc: stable@vger.kernel.org # v4.11+ Patchwork: https://patchwork.linux-mips.org/patch/17929/ Signed-off-by: Ralf Baechle

MIPS: Fix an FCSR access API regression with NT_PRFPREG and MSA

2017-12-12T18:13:12Z

Fix a commit 72b22bbad1e7 ("MIPS: Don't assume 64-bit FP registers for FP regset") public API regression, then activated by commit 1db1af84d6df ("MIPS: Basic MSA context switching support"), that caused the FCSR register not to be read or written for CONFIG_CPU_HAS_MSA kernel configurations (regardless of actual presence or absence of the MSA feature in a given processor) with ptrace(2) PTRACE_GETREGSET and PTRACE_SETREGSET requests nor recorded in core dumps. This is because with !CONFIG_CPU_HAS_MSA configurations the whole of `elf_fpregset_t' array is bulk-copied as it is, which includes the FCSR in one half of the last, 33rd slot, whereas with CONFIG_CPU_HAS_MSA configurations array elements are copied individually, and then only the leading 32 FGR slots while the remaining slot is ignored. Correct the code then such that only FGR slots are copied in the respective !MSA and MSA helpers an then the FCSR slot is handled separately in common code. Use `ptrace_setfcr31' to update the FCSR too, so that the read-only mask is respected. Retrieving a correct value of FCSR is important in debugging not only for the human to be able to get the right interpretation of the situation, but for correct operation of GDB as well. This is because the condition code bits in FSCR are used by GDB to determine the location to place a breakpoint at when single-stepping through an FPU branch instruction. If such a breakpoint is placed incorrectly (i.e. with the condition reversed), then it will be missed, likely causing the debuggee to run away from the control of GDB and consequently breaking the process of investigation. Fortunately GDB continues using the older PTRACE_GETFPREGS ptrace(2) request which is unaffected, so the regression only really hits with post-mortem debug sessions using a core dump file, in which case execution, and consequently single-stepping through branches is not possible. Of course core files created by buggy kernels out there will have the value of FCSR recorded clobbered, but such core files cannot be corrected and the person using them simply will have to be aware that the value of FCSR retrieved is not reliable. Which also means we can likely get away without defining a replacement API which would ensure a correct value of FSCR to be retrieved, or none at all. This is based on previous work by Alex Smith, extensively rewritten. Signed-off-by: Alex Smith Signed-off-by: James Hogan Signed-off-by: Maciej W. Rozycki Fixes: 72b22bbad1e7 ("MIPS: Don't assume 64-bit FP registers for FP regset") Cc: Paul Burton Cc: Dave Martin Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Cc: stable@vger.kernel.org # v3.15+ Patchwork: https://patchwork.linux-mips.org/patch/17928/ Signed-off-by: Ralf Baechle

MIPS: Consistently handle buffer counter with PTRACE_SETREGSET

2017-12-12T18:12:23Z

Update commit d614fd58a283 ("mips/ptrace: Preserve previous registers for short regset write") bug and consistently consume all data supplied to `fpr_set_msa' with the ptrace(2) PTRACE_SETREGSET request, such that a zero data buffer counter is returned where insufficient data has been given to fill a whole number of FP general registers. In reality this is not going to happen, as the caller is supposed to only supply data covering a whole number of registers and it is verified in `ptrace_regset' and again asserted in `fpr_set', however structuring code such that the presence of trailing partial FP general register data causes `fpr_set_msa' to return with a non-zero data buffer counter makes it appear that this trailing data will be used if there are subsequent writes made to FP registers, which is going to be the case with the FCSR once the missing write to that register has been fixed. Fixes: d614fd58a283 ("mips/ptrace: Preserve previous registers for short regset write") Signed-off-by: Maciej W. Rozycki Cc: James Hogan Cc: Paul Burton Cc: Alex Smith Cc: Dave Martin Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Cc: stable@vger.kernel.org # v4.11+ Patchwork: https://patchwork.linux-mips.org/patch/17927/ Signed-off-by: Ralf Baechle