diff options
| author | Marc Zyngier <marc.zyngier@arm.com> | 2017-02-01 11:48:58 +0000 |
|---|---|---|
| committer | Amit Pundir <amit.pundir@linaro.org> | 2018-01-22 13:16:20 +0530 |
| commit | 5db0344a5e6c33ffd0cf9a52ef04e79d32918037 (patch) | |
| tree | d83ebf70f2f6c5a872040af65515a2239757c5db /arch/arm64/kernel | |
| parent | a3a560d6483f91e2df02d014aaf3be0c2e4205e6 (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.
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
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Diffstat (limited to 'arch/arm64/kernel')
| -rw-r--r-- | arch/arm64/kernel/entry.S | 12 | ||||
| -rw-r--r-- | arch/arm64/kernel/traps.c | 19 |
2 files changed, 30 insertions, 1 deletions
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index c09cdc9e6ba5..a33c60262fbf 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -603,7 +603,7 @@ el0_sync: cmp x24, #ESR_ELx_EC_FP_EXC64 // FP/ASIMD exception b.eq el0_fpsimd_exc cmp x24, #ESR_ELx_EC_SYS64 // configurable trap - b.eq el0_undef + b.eq el0_sys cmp x24, #ESR_ELx_EC_SP_ALIGN // stack alignment exception b.eq el0_sp_pc cmp x24, #ESR_ELx_EC_PC_ALIGN // pc alignment exception @@ -731,6 +731,16 @@ el0_undef: mov x0, sp bl do_undefinstr b ret_to_user +el0_sys: + /* + * System instructions, for trapped cache maintenance instructions + */ + enable_dbg_and_irq + ct_user_exit + mov x0, x25 + mov x1, sp + bl do_sysinstr + b ret_to_user el0_dbg: /* * Debug exception handling diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index 6543cd7bcb93..a5fb6f0428a2 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -409,6 +409,25 @@ asmlinkage void __exception do_undefinstr(struct pt_regs *regs) 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) |