This series reworks arm64's syscall handling to minimize the propagation of user-controlled register values into speculated code paths. As with x86 [1], a wrapper is generated for each syscall, which extracts the argument from a struct pt_regs. During kernel entry from userspace, registers are zeroed. The arm64 kernel code directly invokes some syscalls which the x86 code doesn't, so I've added ksys_* wrappers for these, following the x86 example. The rest of the series is arm64-specific. I've pushed the series out to my arm64/syscall-regs branch [2] on kernel.org. Since v1 [3]: * Rebase atop of arm64 for-next/core (for SSBD conflicts) * Move ksys_personality logic into <linux/syscalls.h> * Move kcompat_sys_* wrappers to <linux/compat.h> * Fix scno bounds check to use unsigned comparison * Fix sve_user_reset() call in el0_svc_handler() * Add BUILD_BUG() to the !CONFIG_ARM64_SVE stubs * Accumulate acked-by / reviewed-by tags Since v2 [4]: * Rebase to v4.18-rc1 * Take upper 32 RES0 bits of SCTLR_ELx into account * Accumulate acks Since v3 [5]: * Rebase to v4.18-rc3 to avoid conflict with FPSIMD/SVE fixes * Accumulate acks / reviewed-by tags * Rework __invoke_syscall() for consistency with do_ni_syscall() * Rename sve_user_reset() to sve_user_discard() * Tidied up comment placement * Typo fixes Thanks, Mark. [1] https://lkml.kernel.org/r/20180330093720.6780-1-linux@xxxxxxxxxxxxxxxxxxxx [2] git://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git [3] https://lkml.kernel.org/r/20180514094640.27569-1-mark.rutland@xxxxxxx [4] https://lkml.kernel.org/r/20180601112441.37810-1-mark.rutland@xxxxxxx [5] https://lkml.kernel.org/r/20180618120310.39527-1-mark.rutland@xxxxxxx Mark Rutland (19): arm64: consistently use unsigned long for thread flags arm64: move SCTLR_EL{1,2} assertions to <asm/sysreg.h> arm64: kill config_sctlr_el1() arm64: kill change_cpacr() arm64: move sve_user_{enable,disable} to <asm/fpsimd.h> arm64: remove sigreturn wrappers arm64: convert raw syscall invocation to C arm64: convert syscall trace logic to C arm64: convert native/compat syscall entry to C arm64: don't restore GPRs when context tracking arm64: don't reload GPRs after apply_ssbd arm64: zero GPRs upon entry from EL0 kernel: add ksys_personality() kernel: add kcompat_sys_{f,}statfs64() arm64: remove in-kernel call to sys_personality() arm64: use {COMPAT,}SYSCALL_DEFINE0 for sigreturn arm64: use SYSCALL_DEFINE6() for mmap arm64: convert compat wrappers to C arm64: implement syscall wrappers arch/arm64/Kconfig | 1 + arch/arm64/include/asm/fpsimd.h | 17 +++- arch/arm64/include/asm/syscall_wrapper.h | 80 ++++++++++++++++ arch/arm64/include/asm/sysreg.h | 30 ++---- arch/arm64/include/asm/unistd32.h | 26 ++--- arch/arm64/kernel/Makefile | 5 +- arch/arm64/kernel/armv8_deprecated.c | 8 +- arch/arm64/kernel/cpu_errata.c | 3 +- arch/arm64/kernel/entry.S | 157 ++++--------------------------- arch/arm64/kernel/entry32.S | 121 ------------------------ arch/arm64/kernel/fpsimd.c | 19 ---- arch/arm64/kernel/signal.c | 5 +- arch/arm64/kernel/signal32.c | 6 +- arch/arm64/kernel/sys.c | 19 ++-- arch/arm64/kernel/sys32.c | 127 ++++++++++++++++++++++--- arch/arm64/kernel/syscall.c | 137 +++++++++++++++++++++++++++ arch/arm64/kernel/traps.c | 18 +--- arch/arm64/mm/fault.c | 2 +- fs/statfs.c | 14 ++- include/linux/compat.h | 11 +++ include/linux/syscalls.h | 11 +++ 21 files changed, 453 insertions(+), 364 deletions(-) create mode 100644 arch/arm64/include/asm/syscall_wrapper.h delete mode 100644 arch/arm64/kernel/entry32.S create mode 100644 arch/arm64/kernel/syscall.c -- 2.11.0
