diff options
Diffstat (limited to 'arch/mips/kernel/traps.c')
| -rw-r--r-- | arch/mips/kernel/traps.c | 46 |
1 files changed, 43 insertions, 3 deletions
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c index 94d9141c04c..15fed020215 100644 --- a/arch/mips/kernel/traps.c +++ b/arch/mips/kernel/traps.c @@ -360,6 +360,10 @@ static inline int get_insn_opcode(struct pt_regs *regs, unsigned int *opcode) #define OFFSET 0x0000ffff #define LL 0xc0000000 #define SC 0xe0000000 +#define SPEC3 0x7c000000 +#define RD 0x0000f800 +#define FUNC 0x0000003f +#define RDHWR 0x0000003b /* * The ll_bit is cleared by r*_switch.S @@ -495,6 +499,37 @@ static inline int simulate_llsc(struct pt_regs *regs) return -EFAULT; /* Strange things going on ... */ } +/* + * Simulate trapping 'rdhwr' instructions to provide user accessible + * registers not implemented in hardware. The only current use of this + * is the thread area pointer. + */ +static inline int simulate_rdhwr(struct pt_regs *regs) +{ + struct thread_info *ti = current->thread_info; + unsigned int opcode; + + if (unlikely(get_insn_opcode(regs, &opcode))) + return -EFAULT; + + if (unlikely(compute_return_epc(regs))) + return -EFAULT; + + if ((opcode & OPCODE) == SPEC3 && (opcode & FUNC) == RDHWR) { + int rd = (opcode & RD) >> 11; + int rt = (opcode & RT) >> 16; + switch (rd) { + case 29: + regs->regs[rt] = ti->tp_value; + break; + default: + return -EFAULT; + } + } + + return 0; +} + asmlinkage void do_ov(struct pt_regs *regs) { siginfo_t info; @@ -641,6 +676,9 @@ asmlinkage void do_ri(struct pt_regs *regs) if (!simulate_llsc(regs)) return; + if (!simulate_rdhwr(regs)) + return; + force_sig(SIGILL, current); } @@ -654,11 +692,13 @@ asmlinkage void do_cpu(struct pt_regs *regs) switch (cpid) { case 0: - if (cpu_has_llsc) - break; + if (!cpu_has_llsc) + if (!simulate_llsc(regs)) + return; - if (!simulate_llsc(regs)) + if (!simulate_rdhwr(regs)) return; + break; case 1: |