diff options
| author | Marc Zyngier <marc.zyngier@arm.com> | 2017-02-01 11:48:58 +0000 |
|---|---|---|
| committer | Mister Oyster <oysterized@gmail.com> | 2018-01-15 22:49:15 +0100 |
| commit | 2ce612f1bf210b32b98e95ed3d64b4b4a4dd529d (patch) | |
| tree | 201453135ff8844778977699f521d44a003303f0 /arch/arm64/kernel/traps.c | |
| parent | ad746344214b9f5da9167490bb1d3903f2d638ce (diff) | |
BACKPORT: arm64: Add CNTVCT_EL0 trap handler
Since people seem to make a point in breaking the userspace visible
counter, we have no choice but to trap the access. Add the required
handler.
Bug: 68266545
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
(cherry picked from commit 6126ce0588eb5a0752d5c8b5796a7fca324fd887)
Change-Id: I0705f47c85a78040df38df18f51a4a22500b904d
Diffstat (limited to 'arch/arm64/kernel/traps.c')
| -rw-r--r-- | arch/arm64/kernel/traps.c | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index b138934fc..1d6e418c4 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -32,8 +32,10 @@ #include <linux/sched.h> #include <linux/syscalls.h> +#include <asm/arch_timer.h> #include <asm/atomic.h> #include <asm/debug-monitors.h> +#include <asm/esr.h> #include <asm/traps.h> #include <asm/stacktrace.h> #include <asm/exception.h> @@ -393,6 +395,25 @@ die_sig: arm64_notify_die("Oops - undefined instruction", regs, &info, 0); } +static void cntvct_read_handler(unsigned int esr, struct pt_regs *regs) +{ + int rt = (esr & ESR_ELx_SYS64_ISS_RT_MASK) >> ESR_ELx_SYS64_ISS_RT_SHIFT; + + if (rt != 31) + regs->regs[rt] = arch_counter_get_cntvct(); + regs->pc += 4; +} + +asmlinkage void __exception do_sysinstr(unsigned int esr, struct pt_regs *regs) +{ + if ((esr & ESR_ELx_SYS64_ISS_SYS_OP_MASK) == ESR_ELx_SYS64_ISS_SYS_CNTVCT) { + cntvct_read_handler(esr, regs); + return; + } + + do_undefinstr(regs); +} + long compat_arm_syscall(struct pt_regs *regs); asmlinkage long do_ni_syscall(struct pt_regs *regs) |