kernel.git/arch/mips/math-emu, branch linux-4.19.y

MIPS: math-emu: Write-protect delay slot emulation pages

2019-01-09T16:38:47Z

commit adcc81f148d733b7e8e641300c5590a2cdc13bf3 upstream. Mapping the delay slot emulation page as both writeable & executable presents a security risk, in that if an exploit can write to & jump into the page then it can be used as an easy way to execute arbitrary code. Prevent this by mapping the page read-only for userland, and using access_process_vm() with the FOLL_FORCE flag to write to it from mips_dsemul(). This will likely be less efficient due to copy_to_user_page() performing cache maintenance on a whole page, rather than a single line as in the previous use of flush_cache_sigtramp(). However this delay slot emulation code ought not to be running in any performance critical paths anyway so this isn't really a problem, and we can probably do better in copy_to_user_page() anyway in future. A major advantage of this approach is that the fix is small & simple to backport to stable kernels. Reported-by: Andy Lutomirski Signed-off-by: Paul Burton Fixes: 432c6bacbd0c ("MIPS: Use per-mm page to execute branch delay slot instructions") Cc: stable@vger.kernel.org # v4.8+ Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: Rich Felker Cc: David Daney Signed-off-by: Greg Kroah-Hartman

MIPS: math-emu: Mark fall throughs in switch statements with a comment

2017-12-12T16:20:20Z

Mark intentional fall throughs in switch statements with a consistent comment. In most of the cases, a new comment line containing text "fall through" is inserted. In some of the cases, existing comment contained a variation of the text "fall through" (for example, "FALL THROUGH" or "drop through"). In such cases, the existing comment is modified to contain "fall through". Lastly, in two cases, code segments were described in comments as "fall througs", but were in reality "breaks out" of switch statement. In such cases, existing comments are accordingly modified. Apart from making code easier to follow and debug, this change enables some static code analysers to interpret newly inserted comments as their annotations (and, therefore, not issue warnings of type "fall through in switch statement", which is desireable, since marked fallthroughs are intentional). Signed-off-by: Aleksandar Markovic Cc: Douglas Leung Cc: Goran Ferenc Cc: James Hogan Cc: Maciej W. Rozycki Cc: Manuel Lauss Cc: Miodrag Dinic Cc: Paul Burton Cc: Petar Jovanovic Cc: Raghu Gandham Cc: linux-kernel@vger.kernel.org Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/17588/ Signed-off-by: Ralf Baechle

MIPS: math-emu: Avoid multiple assignment

2017-12-12T16:20:20Z

Replace several instances of multiple assignment with individual assignments. Signed-off-by: Aleksandar Markovic Cc: Douglas Leung Cc: Goran Ferenc Cc: James Hogan Cc: Maciej W. Rozycki Cc: Manuel Lauss Cc: Miodrag Dinic Cc: Paul Burton Cc: Petar Jovanovic Cc: Raghu Gandham Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/17587/ Signed-off-by: Ralf Baechle

MIPS: math-emu: Avoid an assignment within if statement condition

2017-12-12T16:20:20Z

Move invocation of fpu_emu() to be out of if statement condition. This makes code easier to follow and debug, and fixes a checkpatch warning. Signed-off-by: Aleksandar Markovic Cc: Douglas Leung Cc: Goran Ferenc Cc: James Hogan Cc: Maciej W. Rozycki Cc: Miodrag Dinic Cc: Paul Burton Cc: Petar Jovanovic Cc: Raghu Gandham Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/17586/ Signed-off-by: Ralf Baechle

MIPS: math-emu: Declare function srl128() as static

2017-12-12T16:20:19Z

Declare function srl128() as static, since it it used just locally to the source file. This also removes a sparse warning for corresponding file. Signed-off-by: Aleksandar Markovic Cc: Douglas Leung Cc: Goran Ferenc Cc: James Hogan Cc: Miodrag Dinic Cc: Paul Burton Cc: Petar Jovanovic Cc: Raghu Gandham Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/17585/ Signed-off-by: Ralf Baechle

MIPS: math-emu: Avoid definition duplication for macro DPXMULT()

2017-12-12T16:20:19Z

Avoid duplicate definition of macro DPXMULT(). Move its definition to a header. Signed-off-by: Aleksandar Markovic Cc: Douglas Leung Cc: Goran Ferenc Cc: James Hogan Cc: Miodrag Dinic Cc: Paul Burton Cc: Petar Jovanovic Cc: Raghu Gandham Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/17584/ Signed-off-by: Ralf Baechle

MIPS: math-emu: Remove an unnecessary header inclusion

2017-12-12T16:20:19Z

Remove an unnecessary header inclusion of "ieee754dp.h". Signed-off-by: Aleksandar Markovic Cc: Douglas Leung Cc: Goran Ferenc Cc: James Hogan Cc: Miodrag Dinic Cc: Paul Burton Cc: Petar Jovanovic Cc: Raghu Gandham Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/17583/ Signed-off-by: Ralf Baechle

Merge tag 'mips_4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/jhogan/mips

2017-11-15T19:36:08Z

Pull MIPS updates from James Hogan: "These are the main MIPS changes for 4.15. Fixes: - ralink: Fix MT7620 PCI build issues (4.5) - Disable cmpxchg64() and HAVE_VIRT_CPU_ACCOUNTING_GEN for 32-bit SMP (4.1) - Fix MIPS64 FP save/restore on 32-bit kernels (4.0) - ptrace: Pick up ptrace/seccomp changed syscall numbers (3.19) - ralink: Fix MT7628 pinmux (3.19) - BCM47XX: Fix LED inversion on WRT54GSv1 (3.17) - Fix n32 core dumping as o32 since regset support (3.13) - ralink: Drop obsolete USB_ARCH_HAS_HCD select Build system: - Default to "generic" (multiplatform) system type instead of IP22 - Use generic little endian MIPS32 r2 configuration as default defconfig instead of ip22_defconfig FPU emulation: - Fix exception generation for certain R6 FPU instructions SMP: - Allow __cpu_number_map to be larger than NR_CPUS for sparse CPU id spaces Miscellaneous: - Add iomem resource for kernel bss section for kexec/kdump - Atomics: Nudge writes on bit unlock - DT files: Standardise "ok" -> "okay" Minor cleanups: - Define virt_to_pfn() - Make thread_saved_pc static - Simplify 32-bit sign extension in __read_64bit_c0_split() - DMA: Use vma_pages() helper - FPU emulation: Replace unsigned with unsigned int - MM: Removed unused lastpfn - Alchemy: Make clk_ops const - Lasat: Use setup_timer() helper - ralink: Use BIT() in MT7620 PCI driver Platform support: BMIPS: - Enable HARDIRQS_SW_RESEND Broadcom BCM63XX: - Add clkdev lookup support - Update clk driver, UART driver, DTs to handle named refclk from DTs - Split apart various clocks to more closely match hardware - Add ethernet clocks Cavium Octeon: - Remove usage of cvmx_wait() in favour of __delay() ImgTec Pistachio: - DT: Drop deprecated dwmmc num-slots property Ingenic JZ4780: - Add NFS root to Ci20 defconfig - Add watchdog to Ci20 DT & defconfig, and allow building of watchdog driver with this SoC Generic (multiplatform): - Migrate xilfpga (MIPSfpga) platform to the generic platform Lantiq xway: - Fix ASC0/ASC1 clocks" * tag 'mips_4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/jhogan/mips: (46 commits) MIPS: Add iomem resource for kernel bss section. MIPS: cmpxchg64() and HAVE_VIRT_CPU_ACCOUNTING_GEN don't work for 32-bit SMP MIPS: BMIPS: Enable HARDIRQS_SW_RESEND MIPS: pci: Make use of the BIT() macro inside the mt7620 driver MIPS: pci: Remove KERN_WARN instance inside the mt7620 driver MIPS: pci: Remove duplicate define in mt7620 driver MIPS: ralink: Fix typo in mt7628 pinmux function MIPS: ralink: Fix MT7628 pinmux MIPS: Fix odd fp register warnings with MIPS64r2 watchdog: jz4780: Allow selection of jz4740-wdt driver MIPS/ptrace: Update syscall nr on register changes MIPS/ptrace: Pick up ptrace/seccomp changed syscalls MIPS: Fix an n32 core file generation regset support regression MIPS: Fix MIPS64 FP save/restore on 32-bit kernels MIPS: page.h: Define virt_to_pfn() MIPS: Xilfpga: Switch to using generic defconfigs MIPS: generic: Add support for MIPSfpga MIPS: Set defconfig target to a generic system for 32r2el MIPS: Kconfig: Set default MIPS system type as generic MIPS: DTS: Remove num-slots from Pistachio SoC ...

MIPS: math-emu: Use preferred flavor of unsigned integer declarations

2017-11-07T18:33:16Z

Fix occurences of unsigned integer variable declarations that are not preferred by standards of checkpatch scripts. This removes a significant number of checkpatch warnings for files in math-emu directory (several files become completely warning-free), and thus makes easier to spot (now and in the future) other, perhaps more significant, checkpatch errors and warnings. Signed-off-by: Aleksandar Markovic Reviewed-by: James Hogan Cc: Ralf Baechle Cc: Douglas Leung Cc: Goran Ferenc Cc: "Maciej W. Rozycki" Cc: Manuel Lauss Cc: Miodrag Dinic Cc: Paul Burton Cc: Petar Jovanovic Cc: Raghu Gandham Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/17582/ Signed-off-by: James Hogan

MIPS: math-emu: Fix final emulation phase for certain instructions

2017-11-07T18:33:15Z

Fix final phase of . emulation. Provide proper generation of SIGFPE signal and updating debugfs FP exception stats in cases of any exception flags set in preceding phases of emulation. CLASS. instruction may generate "Unimplemented Operation" FP exception. . instructions may generate "Inexact", "Unimplemented Operation", "Invalid Operation", "Overflow", and "Underflow" FP exceptions. . instructions can generate "Unimplemented Operation" and "Invalid Operation" FP exceptions. The proper final processing of the cases when any FP exception flag is set is achieved by replacing "break" statement with "goto copcsr" statement. With such solution, this patch brings the final phase of emulation of the above instructions consistent with the one corresponding to the previously implemented emulation of other related FPU instructions (ADD, SUB, etc.). Fixes: 38db37ba069f ("MIPS: math-emu: Add support for the MIPS R6 CLASS FPU instruction") Fixes: e24c3bec3e8e ("MIPS: math-emu: Add support for the MIPS R6 MADDF FPU instruction") Fixes: 83d43305a1df ("MIPS: math-emu: Add support for the MIPS R6 MSUBF FPU instruction") Fixes: a79f5f9ba508 ("MIPS: math-emu: Add support for the MIPS R6 MAX{, A} FPU instruction") Fixes: 4e9561b20e2f ("MIPS: math-emu: Add support for the MIPS R6 MIN{, A} FPU instruction") Signed-off-by: Aleksandar Markovic Cc: Ralf Baechle Cc: Douglas Leung Cc: Goran Ferenc Cc: "Maciej W. Rozycki" Cc: Miodrag Dinic Cc: Paul Burton Cc: Petar Jovanovic Cc: Raghu Gandham Cc: linux-mips@linux-mips.org Cc: # 4.3+ Patchwork: https://patchwork.linux-mips.org/patch/17581/ Signed-off-by: James Hogan